TORTINI

For your delectation and delight, desultory dicta on the law of delicts.

Meta-Analysis of Observational Studies in Non-Pharmaceutical Litigations

February 26th, 2012

Yesterday, I posted on several pharmaceutical litigations that have involved meta-analytic studies.   Meta-analytic studies have also figured prominently in non-pharmaceutical product liability litigation, as well as in litigation over videogames, criminal recidivism, and eyewitness testimony.  Some, but not all, of the cases in these other areas of litigation are collected below.  In some cases, the reliability or validity of the meta-analyses were challenged; in some cases, the court fleetingly referred to meta-analyses relied upon the parties.  Some of the courts’ treatments of meta-analysis are woefully inadequate or erroneous.  The failure of the Reference Manual on Scientific Evidence to update its treatment of meta-analysis is telling.  See The Treatment of Meta-Analysis in the Third Edition of the Reference Manual on Scientific Evidence” (Nov. 14, 2011).

 

Abortion (Breast Cancer)

Christ’s Bride Ministries, Inc. v. Southeastern Pennsylvania Transportation Authority, 937 F.Supp. 425 (E.D. Pa. 1996), rev’d, 148 F.3d 242 (3d Cir. 1997)

Asbestos

In re Joint E. & S. Dist. Asbestos Litig., 827 F. Supp. 1014, 1042 (S.D.N.Y. 1993)(“adding a series of positive but statistically insignificant SMRs [standardized mortality ratios] together does not produce a statistically significant pattern”), rev’d, 52 F.3d 1124 (2d Cir. 1995).

In Re Asbestos Litigation, Texas Multi District Litigation Cause No. 2004-03964 (June 30, 2005)(Davidson, J.)(“The Defendants’ response was presented by Dr. Timothy Lash.  I found him to be highly qualified and equally credible.  He largely relied on the report submitted to the Environmental Protection Agency by Berman and Crump (“B&C”).  He found the meta-analysis contained in B&C credible and scientifically based.  B&C has not been published or formally accepted by the EPA, but it does perform a valuable study of the field.  If the question before me was whether B&C is more credible than the Plaintiffs’ studies taken together, my decision might well be different.”)

Jones v. Owens-Corning Fiberglas, 288 N.J. Super. 258, 672 A.2d 230 (1996)

Berger v. Amchem Prods., 818 N.Y.S.2d 754 (2006)

Grenier v. General Motors Corp., 2009 WL 1034487 (Del.Super. 2009)

Benzene

Knight v. Kirby Inland Marine, Inc., 363 F. Supp. 2d 859 (N.D. Miss. 2005)(precluding proffered opinion that benzene caused bladder cancer and lymphoma; noting without elaboration or explanation, that meta-analyses are “of limited value in combining the results of epidemiologic studies based on observation”), aff’d, 482 F.3d 347 (5th Cir. 2007)

Baker v. Chevron USA, Inc., 680 F.Supp. 2d 865 (S.D. Ohio 2010)

Diesel Exhaust Exposure

King v. Burlington Northern Santa Fe Ry. Co., 277 Neb. 203, 762 N.W.2d 24 (2009)

Kennecott Greens Creek Mining Co. v. Mine Safety & Health Admin., 476 F.3d 946 (D.C. Cir. 2007)

Eyewitness Testimony

State of New Jersey v. Henderson, 208 N.J. 208, 27 A.3d 872 (2011)

Valle v. Scribner, 2010 WL 4671466 (C.D. Calif. 2010)

People v. Banks, 16 Misc.3d 929, 842 N.Y.S.2d 313 (2007)

Lead

Palmer Asarco Inc., 510 F.Supp.2d 519 (N.D. Okla. 2007)

PCBs

In re Paoli R.R. Yard PCB Litigation, 916 F.2d 829, 856-57 (3d Cir.1990) (‘‘There is some evidence that half the time you shouldn’t believe meta-analysis, but that does not mean that meta-analyses are necessarily in error. It means that they are, at times, used in circumstances in which they should not be.’’) (internal quotation marks and citations omitted), cert. denied, 499 U.S. 961 (1991)

Repetitive Stress

Allen v. International Business Machines Corp., 1997 U.S. Dist. LEXIS 8016 (D. Del. 1997)

Tobacco

Flue-Cured Tobacco Cooperative Stabilization Corp. v. United States Envt’l Protection Agency, 4 F.Supp.2d 435 (M.D.N.C. 1998), vacated by, 313 F.3d 852 (4th Cir. 2002)

Tocolytics – Medical Malpractice

Hurd v. Yaeger, 2009 WL 2516874 (M.D. Pa. 2009)

Toluene

Black v. Rhone-Poulenc, Inc., 19 F.Supp.2d 592 (S.D.W.Va. 1998)

Video Games (Violent Behavior)

Brown v. Entertainment Merchants Ass’n, ___ U.S.___, 131 S.Ct. 2729 (2011)

Entertainment Software Ass’n v. Blagojevich, 404 F.Supp.2d 1051 (N.D. Ill. 2005)

Entertainment Software Ass’n v. Hatch, 443 F.Supp.2d 1065 (D. Minn. 2006)

Video Software Dealers Ass’n v. Schwarzenegger, 556 F.3d 950 (9th Cir. 2009)

Vinyl Chloride

Taylor v. Airco, 494 F. Supp. 2d 21 (D. Mass. 2007)(permitting opinion testimony that vinyl chloride caused intrahepatic cholangiocarcinoma, without commenting upon the reasonableness of reliance upon the meta-analysis cited)

Welding

Cooley v. Lincoln Electric Co., 693 F.Supp.2d 767 (N.D. Ohio. 2010)

Meta-Analysis in Pharmaceutical Cases

February 25th, 2012

The Third Edition of the Reference Manual on Scientific Evidence attempts to cover a lot of ground to give the federal judiciary guidance on scientific, medical, and statistical, and engineering issues.  It has some successes, and some failures.  One of the major problems in coverage in the new Manual is its inconsistent, sparse, and at points out-dated treatment of meta-analysis.   See The Treatment of Meta-Analysis in the Third Edition of the Reference Manual on Scientific Evidence” (Nov. 14, 2011).

As I have pointed out elsewhere, the gaps and problems in the Manual‘s coverage are not “harmless error,” when some courts have struggled to deal with methodological and evaluative issues in connection with specific meta-analyses.  SeeLearning to Embrace Flawed Evidence – The Avandia MDL’s Daubert Opinion” (Jan. 10, 2011).

Perhaps the reluctance to treat meta-analysis more substantively comes from a perception that the technique for analyzing multiple studies does not come up frequently in litigation.  If so, let me help dispel the notion.  I have collected a partial list of drug and medical device cases that have confronted meta-analysis in one form or another.  In some cases, such as the Avandia MDL, a meta-analysis was a key, or the key, piece of evidence.  In other cases, meta-analysis may have been treated more peripherally.  Still, there are over 20 pharmaceutical cases in the last two decades that have dealt with the statistical techniques involved in meta-analysis.  In another post, I will collect the non-pharmaceutical cases as well.

 

Aredia – Zometa

Deutsch v. Novartis Pharm. Corp., 768 F. Supp. 2d 420 (E.D.N.Y. 2011)

 

Avandia

In re Avandia Marketing, Sales Practices and Product Liability Litigation, 2011 WL 13576, *12 (E.D. Pa. 2011)

Avon Pension Fund v. GlaxoSmithKline PLC, 343 Fed.Appx. 671 (2d Cir. 2009)

 

Baycol

In re Baycol Prods. Litig., 532 F.Supp. 2d 1029 (D. Minn. 2007)

 

Bendectin

Daubert v. Merrell Dow Pharm., 43 F.3d 1311 (9th Cir. 1995) (on remand from Supreme Court)

DePyper v. Navarro, 1995 WL 788828 (Mich.Cir.Ct. 1995)

 

Benzodiazepine

Vinitski v. Adler, 69 Pa. D. & C.4th 78, 2004 WL 2579288 (Phila. Cty. Ct. Common Pleas 2004)

 

Celebrex – Bextra

In re Bextra & Celebrex Marketing Sales Practices & Prod. Liab. Litig., 524 F.Supp.2d 1166 (2007)


E5 (anti-endotoxin monoclonal antibody for gram-negative sepsis)

Warshaw v. Xoma Corp., 74 F.3d 955 (1996)

 

Excedrin vs. Tylenol

McNeil-P.C.C., Inc. v. Bristol-Myers Squibb Co., 938 F.2d 1544 (2d Cir. 1991)

 

Fenfluramine, Phentermine

In re Diet Drugs Prod. Liab. Litig., 2000 WL 1222042 (E.D.Pa. 2000)

 

Fosamax

In re Fosamax Prods. Liab. Litig., 645 F.Supp.2d 164 (S.D.N.Y. 2009)

 

Gadolinium

In re Gadolinium-Based Contrast Agents Prod. Liab. Litig., 2010 WL 1796334 (N.D. Ohio 2010)

 

Neurontin

In re Neurontin Marketing, Sales Pracices, and Products Liab. Litig., 612 F.Supp.2d 116 (D. Mass. 2009)

 

Paxil (SSRI)

Tucker v. Smithkline Beecham Corp., 2010 U.S. Dist. LEXIS 30791 (S.D.Ind. 2010)

 

Prozac (SSRI)

Rimberg v. Eli Lilly & Co., 2009 WL 2208570 (D.N.M.)

 

Seroquel

In re Seroquel Products Liab. Litig., 2009 WL 3806434 *5 (M.D. Fla. 2009)

 

Silicone – Breast Implants

Allison v. McGhan Med. Corp., 184 F.3d 1300, 1315 n. 12 (11th Cir. 1999)(noting, in passing that the district court had found a meta-analysis (the “Kayler study”) unreliable “because it was a re-analysis of other studies that had found no statistical correlation between silicone implants and disease”)

Thimerosal – Vaccine

Salmond v. Sec’y Dep’t of Health & Human Services, 1999 WL 778528 (Fed.Cl. 1999)

Hennessey v. Sec’y Dep’t Health & Human Services, 2009 WL 1709053 (Fed.Cl. 2009)

 

Trasylol

In re Trasylol Prods. Liab. Litig., 2010 WL 1489793 (S.D. Fla. 2010)

 

Vioxx

Merck & Co., Inc. v. Ernst, 296 S.W.3d 81 (Tex. Ct. App. 2009)
Merck & Co., Inc. v. Garza, 347 S.W.3d 256 (Tex. 2011)

 

X-Ray Contrast Media (Nephrotoxicity of Visipaque versus Omnipaque)

Bracco Diagnostics, Inc. v. Amersham Health, Inc., 627 F.Supp.2d 384 (D.N.J. 2009)

Zestril

E.R. Squibb & Sons, Inc. v. Stuart Pharms., 1990 U.S. Dist. LEXIS 15788 (D.N.J. 1990)(Zestril versus Squibb’s competing product,
Capote)

 

Zoloft (SSRI)

Miller v. Pfizer, Inc., 356 F.3d 1326 (10th Cir. 2004)

 

Zymar

Senju Pharmaceutical Co. Ltd. v. Apotex Inc., 2011 WL 6396792 (D.Del. 2011)

 

Zyprexa

In re Zyprexa Products Liab. Litig., 489 F.Supp.2d 230 (E.D.N.Y. 2007) (Weinstein, J.)

The MDL Pocket Guide

February 22nd, 2012

Multi-district litigation is the way that the great bulk of products liability cases are now handled in the federal courts.  Once the Judicial Panel on Multi-District Litigation decides that MDL treatment is appropriate, the district courts, around the country, where cases have been filed, transfer their cases to the single district court judge for pre-trial consolidation.  Along with the products cases, the districts will transfer related cases, such as consumer and securities fraud and medical monitoring class actions to the transferee court.

The Federal Judicial Center has recently published a “pocket guide” to describe the process of managing an MDL for products liability cases:   Barbara J. Rothstein and Catherine R. Borden, Managing Multidistrict Litigation in Products Liability Cases: A Pocket Guide for Transferee Judges (2011).  Link or download  The guide weighs in at 53 pages with some standard, and some non-standard, guidance for judges managing MDL products liability cases.  Judge Rothstein, a veteran judge in MDL products litigation, recently stepped down as head of the Federal Judicial Center.

Because there is a significant risk that your MDL judge will read the Pocket Guide, this pamphlet should be on your and your clients’ reading list.  Much of the pamphlet is unexceptional, but there is some non-standard guidance, which you may want to flag for the MDL judge in early briefings.  What follows are just some brief comments on the Guide.

Expert Discovery

Much of the Guide‘s discussion on expert discovery is hornbook law, but the following passage gives some novel, dubious guidance:

“You should be aware of the possibility that not only the parties’ testifying experts, but also the published research on which the experts rely, may be subject to charges of bias. For example, where parties directly or indirectly fund authors of research articles and studies that are relied upon by testifying experts, such funding may be discoverable as relevant to the issue of bias.48  In cases involving disputed evidence on causation, there will often be ongoing scientific studies addressing the disputed issue. You may need to establish procedures for discovery regarding such studies. Generally, courts protect researchers from disclosure of data or opinions relating to an ongoing unpublished study. By contrast, courts generally allow discovery into party-sponsored studies.49

Pocket Guide at § 9.e (citations omitted). The Guide suggests that courts protect researchers from compulsory process to obtain data from “ongoing unpublished” studies, but this begs the question what should be done for studies that already have been published and are being relied upon by the parties, one side, or the other, or both, in litigation.  More troubling is the Guide’s suggestion that an MDL court should unleash discovery against authors of published works for evidence of bias, with a citation to a case that ordered parties to produce lists of payments to authors of articles relied upon by expert witnesses.

The case-law support for the suggested approach is thin – just one case – and it involves serious problems.  For instance, expert witnesses must itemize all studies, publications, data, and the like, which they have “considered.”  The expert witnesses’ reports must give a detailed recitation of their opinions and the bases for their opinions.  Does the mere appearance of an article on an expert witness’s “consideration” list trigger this invasive discovery?  The Guide‘s language and citation suggest so, but there is little reason or logic to support such an inquiry.  The authors of a study relied upon might appear to be more appropriate targets for this inquiry, but sometimes studies cut different ways, and an expert witness for one side or the other might reasonably rely upon some data and analyses and not others from a single study.  The process contemplated by the Guide appears to dichotomize, in a simple-minded way, the entire body of research that might bear upon scientific questions in a litigation.

Second, the discovery exercise described in pamphlet raises concerns about the confidentiality of consultations made with experts who were never considered for a testifying role in litigation. These consultations may have been made with the understanding that the fact and the substance of the consultation would be confidential. Some consultants, on both sides of litigations, may be concerned about powerful superiors in their universities who are allied with litigants or their regulatory allies on one side or the other.

Third, both sides in MDL cases are likely to speak to a good number of experts in the field. The parties on all sides will generally interview experts based upon their reported views or their interest in issues that are relevant to the litigation. Before courts create lists of “tainted” scientific papers, they might well consider the timing of the authorship and whether the payments were made before or after the author in question wrote the article that is relied upon.

Fourth, there is an unfair asymmetry involved in this exercise. Many MDL cases involve one or a few defendants, and it is generally feasible for those defendants and their counsel to trace all payments made to scientists, for whatever reason. Plaintiffs’ counsel, serving on a Steering Committee, may express an inability to contact every plaintiffs’ counsel who has taken state or federal cases related to the MDL, or who has considered taking cases, and who has spoken to experts as part of their research or representations.  While that claimed inability may well be real (or not), it leaves the reporting on one side incomplete, and creates prejudice to the side (usually the defense) that has the ability to provide a definitive list.

Fifth, the scope of the disclosure exercise cannot be easily and fairly circumscribed. The defendants or the Plaintiffs’ Steering Committee may not have paid any money to scientists who has worked with other litigants in other litigations. Those scientists, who are not financially tied to the parties in the particular MDL, may still have substantial biases as a result of having worked with counsel – indeed, they may be the same counsel as are involved in the MDL – but the disclosure rules obscure their biases and create an imbalanced view of who is “interested,” and who is “disinterested.”  For instance, a prominent plaintiffs’ counsel on the MDL’s Plaintiffs’ Steering Committee may have worked with an expert, and even may have encouraged that expert to publish on a topic that would affect a wide array of litigations, including the MDL where discovery is proposed into the expert’s “biases.”  If the expert, however, had no engagement for the MDL itself, the association with plaintiffs’ counsel in other cases would appear to immunize this expert from discovery into payments and biases.

Sixth, the suggested procedure will not bring in information from plaintiffs’ counsel, whose cases are filed only in state courts, and who are thus not subject to orders of the MDL court.  The state court plaintiffs could work up any number of consulting expert witnesses, and have them publish extensively on the MDL issues, but the federal MDL court’s discovery will not reveal the subterfuge.  The practice of the state court consultations will be “privileged” under most states’ rules on expert witnesses.  The defendants, of course, will be in both state and federal courts, and thus all their consulting expert witnesses will be subject to discovery.

The Guide‘s suggestion does not appear to have been thought through very carefully.

 

Attorney Fees

Who can be against attorney’s fees, but common-benefit funds raise some thorny cy pres problems when the MDL has wound down:

“In a large MDL, many courts appoint common benefit fee committees, charged either with auditing and recommending common benefit compensation requests, or determining the final allocation of a common benefit fee award among the competing common benefit attorneys.”

Pocket Guide at § 4.b.

The discussion of common-benefit funds could benefit from discussing some of the mechanics of ensuring that monies in the funds are returned to claimants at the conclusion of the litigation to avoid improprieties, such as have been seen in MDL 926, In re Silicone Gel Breast Implants Litigation.  See SKAPP A LOT (April 30, 2010).

 

Name that MDL

The Pocket Guide has no suggestions about how to name the MDL, but while I am whining, here is another complaint:  why are product MDLs typically given names like:  In re Widget Products Liability Litigation?  Doesn’t this prejudge the issue in a way unfairly to the defendant?  Every videotaped deposition will begin with a statement from the videographer to the effect that the deposition is being taken in the Widget liability litigation, or something like that.  Why aren’t these MDLs named:  In re Widget Safety Litigation?  Or, In re Widget Alleged Product Liability Litigation?  The names are already a mouthful; they should at least be fair.

Unreported Decisions on Expert Witness Opinion in New Jersey

February 21st, 2012

In New Jersey, as in other states, unpublished opinions have a quasi-outlaw existence.  According to the New Jersey Rules of Court, unpublished opinions are not precedential.  By court fiat, the court system has declared that it can act a certain way in a given case, and not have to follow its own lead in other cases:

No unpublished opinion shall constitute precedent or be binding upon any court. Except for appellate opinions not approved for publication that have been reported in an authorized administrative law reporter, and except to the extent required by res judicata, collateral estoppel, the single controversy doctrine or any other similar principle of law, no unpublished opinion shall be cited by any court. No unpublished opinion shall be cited to any court by counsel unless the court and all other parties are served with a copy of the opinion and of all contrary unpublished opinions known to counsel.

New Jersey Rule of Court 1:36-3 (Unpublished Opinions).

Litigants down the road may feel that they are not being given the equal protection of the law, but never mind.  Res judicata and collateral estoppel are in, but stare decisis is out.  Consistency and coherence are so difficult, surely it is better to be free from having from these criteria of rationality unless we decide to “opt in” by publishing opinions with our decisions.  As many other scholars and commentators have noted, rules of this sort allow decisions from other states, and even other countries, to be potentially persuasive, whereas by court rule and fiat, an unpublished decision of the deciding court can not have any precedential value.  Why then permit unpublished cases to be cited at all?

Having tracked decisions, published and un-, in New Jersey for many years, I am left with an impression that the Appellate Division has a tendency to refuse to publish opinions of decisions in which it has reversed the trial court’s refusal to exclude expert witness testimony, or in which it has affirmed the trial court’s exclusion of expert testimony.  Opinions that explain the affirmance of a denial of expert witness exclusion or the reversal of a trial court’s grant of exclusion appear to be published more often.  Stated as a four-fold table:

  Trial Court Permits Expert Trial Court Bars Expert
Appellate Court Affirms Published Not Published
Appellate Court Reverses Not Published Publish

My impression is that there is an institutional bias against creating a body of law that illuminates the criteria for admission and for exclusion of expert witness opinion testimony. This is only an impression, and I do not have statistics, descriptive or inferential on these judicial behaviors.  From a jurisprudential perspective, the affirmance of an exclusion below, or the reversal of a denial of exclusion below, should be at least as important as publishing the reversal of an exclusion below.  The goal of announcing to the Bar and to trial judges the criteria for inclusion and exclusion would seem to suggest greater publication of the opinions, from the two unpublished cells, in the contingency table, above.

No citation and no precedent rules are deeply problematic, and have attracted a great deal of scholarly attention.  See Erica Weisgerber, “Unpublished Opinions: A Convenient Means to an Unconstitutional End,” 97 Georgetown L.J. 621 (2009);  Rafi Moghadam, “Judge Nullification: A Perception of Unpublished Opinions,” 62 Hastings L.J. 1397 (2011);  Norman R. Williams, “The failings of Originalism:  The Federal Courts and the Power of Precedent,” 37 U.C.. Davis L. Rev. 761 (2004);  Dione C. Greene, “The Federal Courts of Appeals, Unpublished Decisions, and the ‘No-Citation Rule,” 81 Indiana L.J. 1503 (2006);  Vincent M. Cox, “Freeing Unpublished Opinions from Exile: Going Beyond the Citation Permitted by Proposed Federal Rule of Appellate Procedure 32.1,” 44 Washburn L.J. 105 (2004);  Sarah E. Ricks, “The Perils of Unpublished Non-Precedential Federal Appellate Opinions: A Case Study of The Substantive Due Process State-Created Danger Doctrine in One Circuit,” 81 Wash. L.Rev. 217 (2006);  Michael J. Woodruff, “State Supreme Court Opinion Publication in the Context of Ideology and Electoral Incentives.” New York University Department of Politics (March 2011);   Michael B. W. Sinclair, “Anastasoff versus Hart: The Constitutionality and Wisdom of Denying Precedential Authority to Circuit Court Decisions.”  See generally The Committee for the Rule of Law (website) (collecting scholarship and news on the issue of unpublished and supposedly non-precedential opinions).

What would be useful is an empirical analysis of the New Jersey Appellate Division’s judicial behavior in deciding whether or not to publish decisions for each of the four cells, in the four-fold table, above.  If my impression is correct, the suggestion of institutional bias would give further support to the abandonment of N.J. Rule of Court 1:36-3.

When There Is No Risk in Risk Factor

February 20th, 2012

Some of the terminology of statistics and epidemiology is not only confusing, but it is misleading.  Consider the terms “effect size,” “random effects,” and “fixed effect,” which are all used to describe associations even if known to be non-causal.  Biostatisticians and epidemiologists know that the terms are about putative or potential effects, but the sloppy, short-hand nomenclature can be misleading.

Although “risk” has a fairly precise meaning in scientific parlance, the usage for “risk factor” is fuzzy, loose, and imprecise.  Journalists and plaintiffs’ lawyers use “risk factor,” much as they another frequently abused term in their vocabulary:  “link.”  Both “risk factor” and “link” sound as though they are “causes,” or at least as though they have something to do with causation.  The reality is usually otherwise.

The business of exactly what “risk factor” means is puzzling and disturbing.  The phrase seems to have gained currency because it is squishy and without a definite meaning.  Like the use of “link” by journalists, the use of “risk factor” protects the speaker against contradiction, but appears to imply a scientifically valid conclusion.  Plaintiffs’ counsel and witnesses love to throw this phrase around precisely because of its ambiguity.  In journal articles, authors sometimes refer to any exposure inquired about in a case-control study to be a “risk factor,” regardless of the study result.  So a risk factor can be merely an “exposure of interest,” or a possible cause, or a known cause.

The author’s meaning in using the phrase “risk factor” can often be discerned from context.  When an article reports a case-control study, which finds an association with an exposure to some chemical the article will likely report in the discussion section that the study found that chemical to be a risk factor.  The context here makes clear that the chemical was found to be associated with the outcome, and that chance was excluded as a likely explanation because the odds ratio was statistically significant.  The context is equally clear that the authors did not conclude that the chemical was a cause of the outcome because they did not rule out bias or confounding; nor did they do any appropriate analysis to reach a causal conclusion and because their single study would not have justified reaching a causal association.

Sometimes authors qualify “risk factor” with an adjective to give more specific meaning to their usage.  Some of the adjectives used in connection with the phrase include:

– putative, possible, potential, established, well-established, known, certain, causal, and causative

The use of the adjective highlights the absence of a precise meaning for “risk factor,” standing alone.  Adjectives such as “established,” or “known” imply earlier similar findings, which are corroborated by the study at hand.  Unless “causal” is used to modify “risk factor,” however, there is no reason to interpret the unqualified phrase to imply a cause.

Here is how the phrase “risk factor” is described in some noteworthy texts and treatises.

Legal Treatises

Professor David Faigman, and colleagues, with some understatement, note that the term “risk factor is loosely used”:

Risk Factor An aspect of personal behavior or life-style, an environmental exposure, or an inborn or inherited characteristic, which on the basis of epidemiologic evidence is known to be associated with health-related condition(s) considered important to prevent. The term risk factor is rather loosely used, with any of the following meanings:

1. An attribute or exposure that is associated with an increased probability of a specified outcome, such as the occurrence of a disease. Not necessarily a causal factor.

2. An attribute or exposure that increases the probability of occurrence of disease or other specified outcome.

3. A determinant that can be modified by intervention, thereby reducing the probability of occurrence of disease or other specified outcomes.”

David L. Faigman, Michael J. Saks, Joseph Sanders, and Edward Cheng, Modern Scientific Evidence:  The Law and Science of Expert Testimony 301, vol. 1 (2010)(emphasis added).

The Reference Manual on Scientific Evidence (2011) (RMSE3d) does not offer much in the way of meaningful guidance here.  The chapter on statistics in the third edition provides a somewhat circular, and unhelpful definition.  Here is the entry in that chapter’s glossary:

risk factor. See independent variable.

RMSE3d at 295.  If the glossary defined “independent variable” as a simply a quantifiable variable that was being examined for some potential relationship with the outcome, or dependent, variable, the RMSE would have avoided error.  Instead the chapter’s glossary, as well as its text, defines independent variables as “causes,” which begs the question why do a study to determine whether the “independent variable” is even a candidate for a causal factor?  Here is how the statistics chapter’s glossary defines independent variable:

“Independent variables (also called explanatory variables, predictors, or risk factors) represent the causes and potential confounders in a statistical study of causation; the dependent variable represents the effect. ***. “

RMSE3d at 288.  This is surely circular.  Studies of causation are using independent variables that represent causes?  There would be no reason to do the study if we already knew that the independent variables were causes.

The text of the RMSE chapter on statistics propagates the same confusion:

“When investigating a cause-and-effect relationship, the variable that represents the effect is called the dependent variable, because it depends on the causes.  The variables that represent the causes are called independent variables. With a study of smoking and lung cancer, the independent variable would be smoking (e.g., number of cigarettes per day), and the dependent variable would mark the presence or absence of lung cancer. Dependent variables also are called outcome variables or response variables. Synonyms for independent variables are risk factors, predictors, and explanatory variables.”

FMSE3d at 219.  In the text, the identification of causes with risk factors is explicit.  Independent variables are the causes, and a synonym for an independent variable is “risk factor.”  The chapter could have avoided this error simply by the judicious use of “putative,” or “candidate” in front of “causes.”

The chapter on epidemiology exercises more care by using “potential” to modify and qualify the risk factors that are considered in a study:

“In contrast to clinical studies in which potential risk factors can be controlled, epidemiologic investigations generally focus on individuals living in the community, for whom characteristics other than the one of interest, such as diet, exercise, exposure to other environmental agents, and genetic background, may distort a study’s results.”

FMSE3d at 556 (emphasis added).

 

Scientific Texts

Turning our attention to texts on epidemiology written for professionals rather than judges, we find that sometimes the term “risk factor” with a careful awareness of its ambiguity.

Herbert I. Weisberg is a statistician whose firm, Correlation Research Inc., specializes in the applied statistics in legal issues.  Weisberg recently published an interesting book on bias and causation, which is recommended reading for lawyers who litigate claimed health effects.  Weisberg’s book defines “risk factor” as merely an exposure of interest in a study that is looking for associations with a harmful outcome.  He insightfully notes that authors use the phrase “risk factor” and similar phrases to avoid causal language:

“We will often refer to this factor of interest as a risk factor, although the outcome event is not necessarily something undesirable.”

Herbert I. Weisberg, Bias and Causation:  Models and Judgment for Valid Comparisons 27 (2010).

“Causation is discussed elliptically if at all; statisticians typically employ circumlocutions such as ‘independent risk factor’ or ‘explanatory variable’ to avoid causal language.”

Id. at 35.

Risk factor : The risk factor is the exposure of interest in an epidemiological study and often has the connotation that the outcome event is harmful or in some way undesirable.”

Id. at 317.   This last definition is helpful in illustrating a balanced, fair definition that does not conflate risk factor with causation.

*******************

Lemuel A. Moyé is an epidemiologist who testified in pharmaceutical litigation, mostly for plaintiffs.  His text, Statistical Reasoning in Medicine:  The Intuitive P-Value Primer, is in places a helpful source of guidance on key concepts.  Moyé puts no stock in something’s being a risk factor unless studies show a causal relationship, established through a proper analysis.  Accordingly, he uses “risk factor” to signify simply an exposure of interest:

4.2.1 Association versus Causation

An associative relationship between a risk factor and a disease is one in which the two appear in the same patient through mere coincidence. The occurrence of the risk factor does not engender the appearance of the disease.

Causal relationships on the other hand are much stronger. A relationship is causal if the presence of the risk factor in an individual generates the disease. The causative risk factor excites the production of the disease. This causal relationship is tight, containing an embedded directionality in the relationship, i.e., (1) the disease is absence in the patient, (2) the risk factor is introduced, and (3) the risk factor’s presence produces the disease.

The declaration that a relationship is causal has a deeper meaning then the mere statement that a risk factor and disease are associated. This deeper meaning and its implications for healthcare require that the demonstration of a causal relationship rise to a higher standard than just the casual observation of the risk factor and disease’s joint occurrence.

Often limited by logistics and the constraints imposed by ethical research, the epidemiologist commonly cannot carry out experiments that identify the true nature of the risk factor–disease relationship. They have therefore become experts in observational studies. Through skillful use of observational research methods and logical thought, epidemiologists assess the strength of the links between risk factors and disease.”

Lemuel A. Moyé, Statistical Reasoning in Medicine:  The Intuitive P-Value Primer 92 (2d ed. 2006)

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In A Dictionary of Epidemiology, which is put out by the International Epidemiology Association, a range of meanings is acknowledged, although the range is weighted toward causality:

“RISK FACTOR (Syn: risk indicator)

1. An aspect of personal behavior or lifestyle, an environmental exposure, or an inborn or inherited characteristic that, on the basis of scientific evidence, is known to be associated with meaningful health-related condition(s). In the twentieth century multiple cause era, a synonymous with determinant acting at the individual level.

2. An attribute or exposure that is associated with an increased probability of a specified outcome, such as the occurrence of a disease. Not necessarily a causal factor: it may be a risk marker.

3. A determinant that can be modified by intervention, thereby reducing the probability of occurrence of disease or other outcomes. It may be referred to as a modifiable risk factor, and logically must be a cause of the disease.

The term risk factor became popular after its frequent use by T. R. Dawber and others in papers from the Framingham study.346 The pursuit of risk factors has motivated the search for causes of chronic disease over the past half-century. Ambiguities in risk and in risk-related concepts, uncertainties inherent to the concept, and different legitimate meanings across cultures (even if within the same society) must be kept in mind in order to prevent medicalization of life and iatrogenesis.124–128,136,142,240

Miquel Porta, Sander Greenland, John M. Last, eds., A Dictionary of Epidemiology 218-19 (5th ed. 2008).  We might add that the uncertainties inherent in risk concepts should be kept in mind to prevent overcompensation for outcomes not shown to be caused by alleged tortogens.

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One introductory text uses “risk factor” as a term to describe the independent variable, while acknowledging that the variable does not become a risk factor until after the study shows an association between factor and the outcome of interest:

“A case-control study is one in which the investigator seeks to establish an association between the presence of a characteristic (a risk factor).”

Sylvia Wassertheil-Smoller, Biostatistics and Epidemiology: A Primer for Health and Biomedical Professionals 104 (3d ed. 2004).  See also id. at 198 (“Here, also, epidemiology plays a central role in identifying risk factors, such as smoking for lung cancer”).  Although it should be clear that much more must happen in order to show a risk factor is causally associated with an outcome, such as lung cancer, it would be helpful to spell this out.  Some texts simply characterize risk factor as associations, not necessarily causal in nature.  Another basic text provides:

“Analytical studies examine an association, i.e. the relationship between a risk factor and a disease in detail and conduct a statistical test of the corresponding hypothesis … .”

Wolfgang Ahrens & Iris Pigeot, eds., Handbook of Epidemiology 18 (2005).  See also id. at 111 (Table describing the reasoning in a case-control study:    “Increased prevalence of risk factor among diseased may indicate a causal relationship.”)(emphasis added).

These texts, both legal and scientific, indicate a wide range of usage and ambiguity for “risk factor.”  There is a tremendous potential for the unscrupulous expert witness, or the uneducated lawyer, to take advantage of this linguistic latitude.  Courts and counsel must be sensitive to the ambiguity and imprecision in usages of “risk factor,” and the mischief that may result.  The Reference Manual on Scientific Evidence needs to sharpen and update its coverage of this and other statistical and epidemiologic issues.

When Is Risk Really Risk?

February 14th, 2012

The term “risk” has a fairly precise meaning in scientific parlance.  The following is a typical definition:

RISK The probability that an event will occur, e.g., that an individual will become ill or die within a stated period of time or by a certain age. Also, a nontechnical term encompassing a variety of measures of the probability of a (generally) unfavorable outcome. See also probability.

Miquel Porta, ed., A Dictionary of Epidemiology 212-18 (5th ed. 2008)(sponsored by the Internat’l Epidemiological Ass’n).

In other words, a risk is an ex ante cause.  The probability is not a qualification about whether there is a causal relationship, but rather whether any person at risk will develop the outcome of interest.  Such is the nature of stochastic risks.

Regulatory agencies often use the term “risk” metaphorically, as a fiction to justify precautionary regulations.  Although there may be nothing wrong with such precautionary initiatives, regulators often imply a real threat of harm from what can only be a hypothetical harm.  Why?  If for no other reason, regulators operate with a “wish bias” in favor of the reality of the risk they wish to avert if risk it should be.  We can certainly imagine the cognitive slippage that results from the need to motivate the regulated actors to comply with regulations, and at times, to prosecute the noncompliant.

Plaintiffs’ counsel in personal injury and class action litigation have none of the regulators’ socially useful motives for engaging in distortions of the meaning of the word “risk.”  In the context of civil litigation, plaintiffs’ counsel use the term “risk,” borrowed from the Humpty-Dumpty playbook:

“When I use a word,” Humpty Dumpty said, in rather a scornful tone, “it means just what I choose it to mean—neither more nor less.”
“The question is,” said Alice, “whether you can make words mean so many different things.”
“The question is,” said Humpty Dumpty, “which is to be master — that’s all.”

Lewis Carroll, Through the Looking-Glass 72 (Raleigh 1872).

Undeniably, the word mangling and distortion have had some success with weak-minded judges, but Humpty-Dumpty linguistics had a fall recently in the Third Circuit.  Others have written about it, but I am only just getting around to read the analytically precise and insightful decision in Gates v. Rohm and Haas Co., 655 F.3d 255 (3d Cir. 2011).  See Sean Wajert, “Court of Appeals Rejects Medical Monitoring Class Action” (Aug. 31, 2011); Carl A. Solano, “Appellate Court Consensus on Medical Monitoring Class Actions Solidifies” (Sept. 12, 2011).

Gates was an attempted class action, in which the district court denied plaintiffs’ motion for certification of a medical monitoring and property damage class.  265 F.R.D. 208 (E.D.Pa. 2010)(Pratter, J.).  Plaintiffs contended that they were exposed to varying amounts of vinyl chloride exposure in air, and perhaps in water at levels too low to detect. Gates, 655 F.3d at 258-59.   The class’s request for medical monitoring foundered because plaintiffs were unable to prove that they were all exposed to a level of vinyl chloride that created a significant risk of serious latent disease for all class members. Id. at 267-68.

With no scientific evidence in hand, the plaintiffs tried to maintain that they were “at risk” on the basis of EPA regulations, which set a very low, precautionary threshold, but the district and circuit courts rebuffed this use of regulatory “risk” language:

The court identified two problems with the proposed evidence. First, it rejected the plaintiffs’ proposed threshold—exposure above 0.07µ/m3, developed as a regulatory threshold by the EPA for mixed populations of adults and children—as a proper standard for determining liability under tort law. Second, the court correctly noted, even if the 0.07 µ/m3 standard were a correct measurement of the aggregate threshold, it would not be the threshold for each class member who may be more or less susceptible to diseases from exposure to vinyl chloride.18 Although the positions of regulatory policymakers are relevant, their risk assessments are not necessarily conclusive in determining what risk exposure presents to specified individuals. See Federal Judicial Center, Reference Manual on Scientific Evidence 413 (2d ed.2000) (“While risk assessment information about a chemical can be somewhat useful in a toxic tort case, at least in terms of setting reasonable boundaries as to the likelihood of causation, the impetus for the development of risk assessment has been the regulatory process, which has different goals.”); id. at 423 (“Particularly problematic are generalizations made in personal injury litigation from regulatory positions…. [I]f regulatory standards are discussed in toxic tort cases to provide a reference point for assessing exposure levels, it must be recognized that  there is a great deal of variability in the extent of evidence required to support different regulations.”).

Thus, plaintiffs could not carry their burden of proof for a class of specific persons simply by citing regulatory standards for the population as a whole. Cf. Wright v. Willamette Indus., Inc., 91 F.3d 1105, 1107 (8th Cir.1996) (“Whatever may be the considerations that ought to guide a legislature in its determination of what the general good requires, courts and juries, in deciding cases, traditionally make more particularized inquiries into matters of cause and effect.”).

Plaintiffs have failed to propose a method of proving the proper point where exposure to vinyl chloride presents a significant risk of developing a serious latent disease for each class member.

Plaintiffs propose a single concentration without accounting for the age of the class member being exposed, the length of exposure, other individual factors such as medical history, or showing the exposure was so toxic that such individual factors are irrelevant. The court did not abuse its discretion in concluding individual issues on this point make trial as a class unfeasible, defeating cohesion.

Id. at 268.  For class actions, the inability to invoke a low threshold of “permissible” exposure may be the death knell of medical monitoring and personal injury class actions.  The implications of the Gates court’s treatment of “regulatory risk” is, however, more far reaching.  Sometimes risk is not really risk at all.  The ambiguity of the risk in risk assessment has confused judges from the lowest magistrate up to Supreme Court justices.  It is time to disambiguate.  See General Electric v. Joiner, 522 U.S. 136, 153-54 (1997) (Stevens, J., dissenting in part) (erroneously assuming that plaintiffs’ expert witness was justified in relying upon a weight-of-evidence methodology because such methodology is often used in risk assessment).

Two Articles of Interest in JAMA – Nocebo Effects; Medical Screening

February 12th, 2012

Two articles in this week’s Journal of the American Medical Association (JAMA) are of interest to lawyers who litigate, or counsel about, health effects.

One article deals with the nocebo effect, which is the dark side of the placebo effect.  Placebos can induce beneficial outcomes because of the expectation of useful therapy; nocebos can induce harmful outcomes because of the expectation of injury. The viewpoint article in JAMA points out that nocebo effects, like placebo effects, result from the “psychosocial context or therapeutic environment” affecting a patient’s perception of his state of health or illness.  Luana Colloca, MD, PhD, and Damien Finniss, MSc Med., “Nocebo Effects, Patient-Clinician Communication, and Therapeutic Outcomes,” 307 J. Am. Med. Ass’n 567, 567 (2012).

The authors discuss how clinicians can inadvertently prejudice health outcomes by how they frame outcome information to patients.  Importantly, Colloca and Finniss also note that the negative expectations created by the nocebo communication can take place in the process of obtaining informed consent.

The litigation significance is substantial because the creation of negative expectations is not the exclusive domain of clinicians.  Plaintiffs’ counsel, support and advocacy groups, and expert witnesses, even when well meaning, can similarly create negative expectations for health outcomes.  These actors often enjoy undeserved authority among their audience of litigants or claimants.  The extremely high rate of psychogenic illness found in many litigations is the result.  The harmful communications, however, are not limited to plaintiffs’ lawyers and their auxiliaries.  As Colloca and Finniss point out, nocebo effects can be induced by well-meaning warnings and disclosure of information from healthcare providers to patients.  Id. at 567.  The potential to induce negative harms in this way has the obvious consequence for the tort system:  more warnings are not always beneficial.  Indeed, warnings themselves can bring about harm.  This realization should temper courts’ enthusiasms for the view that more warnings are always better.  Warnings about adverse health outcomes should be based upon good scientific bases.

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The other article from this week’s issue of JAMA addresses the harms of screening.  Steven H. Woolf, MD, MPH, and Russell Harris, MD, MPH, “The Harms of Screening: New Attention to an Old Concern,” 307 J. Am. Med. Ass’n 565 (2012).    As I pointed out on these pages, screening for medical illnesses carries significant health risks to patients and ethical risks for the healthcare providers.  SeeEthics and Daubert: The Scylla and Charybdis of Medical Monitoring” (Feb. 1, 2012).  Bayes’ Theorem teaches us that even very high likelihood ratios for screening tests will yield true positive cases swamped by false positive cases when the baseline prevalence is low.  See Jonathan Deeks and Douglas Altman, “Diagnostic tests 4: likelihood ratios,” 329 Brit. Med. J. 168 (2004) (Providing a useful nomogram to illustrate how even highly accurate tests, with high likelihood ratios, will produce more false than true positive cases when the baseline prevalence of disease is low).

The viewpoint piece by Woolf and Harris emphasizes the potential iatrogenic harms from screening:

  • physical injury from the test itself (as in colonic perforations from colonoscopy);
  • cascade of further testing, with further risk of harm, both physical and emotional;
  • anxiety and emotional distress over abnormal results;
  • overdiagnosis; and
  • the overtreatment of conditions that are not substantial threats to patients’ health

These issues should have an appropriately chilling effect on judicial enthusiasm for medical monitoring and surveillance claims.  Great care is required to fashion a screening plan for patients or claimants.  Of course, there are legal risks as well, as when plaintiffs’ counsel fail to obtain the necessary prescriptions or permits to conduct radiological screenings.  See Schachtman “State Regulators Impose Sanction for Unlawful Silicosis Screenings,” 17(13) Wash. Leg. Fdtn. Legal Op. Ltr. (May 25, 2007).  Caveat litigator.

Interstitial Doubts About the Matrixx

February 6th, 2012

Statistics professors are excited that the United States Supreme Court issued an opinion that ostensibly addressed statistical significance.  One such example of the excitement is an article, in press, by Joseph B. Kadane, Professor in the Department of Statistics, in Carnegie Mellon University, Pittsburgh, Pennsylvania.  See Joseph B. Kadane, “Matrixx v. Siracusano: what do courts mean by ‘statistical significance’?” 11[x] Law, Probability and Risk 1 (2011).

Professor Kadane makes the sensible point that the allegations of adverse events did not admit of an analysis that would imply statistical significance or its absence.  Id. at 5.  See Schachtman, “The Matrixx – A Comedy of Errors” (April 6, 2011)”;  David Kaye, ” Trapped in the Matrixx: The U.S. Supreme Court and the Need for Statistical Significance,” BNA Product Safety and Liability Reporter 1007 (Sept. 12, 2011).  Unfortunately, the excitement has obscured Professor Kadane’s interpretation of the Court’s holding, and has led him astray in assessing the importance of the case.

In the opening paragraph of his paper, Professor Kadane quotes from the Supreme Court’s opinion that “the premise that statistical significance is the only reliable indication of causation … is flawed,” Matrixx Initiatives, Inc. v. Siracusano, ___ U.S. ___, 131 S.Ct. 1309 (2011).  The quote is accurate, but Professor Kadane proceeds to claim that this quote represents the holding of the Court. Kadane, supra at 1. The Court held no such thing.

Matrixx was a security fraud class action suit, brought by investors who claimed that the company misled them when they spoke to the market about the strong growth prospects of the company’s product, Zicam cold remedy, when they had information that raised concerns that might affect the product’s economic viability and its FDA license.  The only causation required for the plaintiffs to show was an economic loss caused by management’s intentional withholding of “material” information that should have been disclosed under all the facts and circumstances.  Plaintiffs do not have to prove that the medication causes the harm alleged in personal injury actions.  Indeed, it might turn out to be indisputable that the medication does not cause the alleged harm, but earlier, suggestive studies would provoke regulatory intervention and even a regulatory decision to withdraw the product from the market.  Investors obviously could be hurt under this scenario as much as, if not more than, if the medication caused the harms alleged by personal-injury plaintiffs. 

Kadane’s assessment goes awry in suggesting that the Supreme Court issued a holding about facts that were neither proven nor necessary for it to reach its decision.  Court can, and do, comment, note, and opine about many unnecessary facts or allegations in reaching a holding, but these statements are obiter dicta, if they are not necessary to the disposition of the case. Because medical causation was not required for the Supreme Court to reach its decision, its presence or absence was not, and could not, be part of the Court’s holding. 

Kadane makes a similar erroneous statement that the lower appellate courts, which earlier had addressed “statistical significance,” properly or improperly understood, found that “statistical significance in the strict sense [was] neither necessary … nor sufficient … to require action to remove a drug from the market.”  Id. at 6.  The earlier appellate decisions addressed securities fraud, however, not regulatory action of withdrawal of a product.  Kadane’s statement mistakes what was at issue, and what was decided, in all the cases discussed.

Kadane seems at least implicitly to recognize that medical causation is not at issue when he states that “the FDA does not require proof of causation but rather reasonable evidence of an association before a warning is issued.”  Id. at 7 (internal citation omitted).  All that had to have happened for the investors to have been harmed by the Company’s misleading statements was for Matrixx Initiatives to boast about future sales, and to claim that there were no health issues that would lead to regulatory intervention, when they had information raising doubts about their claim of no health issues. See FDA Regulations, 21 U.S.C. § 355(d), (e)(requiring drug sponsor to show adequate testing, labeling, safety, and efficacy); see also 21 C.F.R. § 201.57(e) (requiring warnings in labeling “as there is reasonable evidence of an association of a serious hazard with a drug; a causal relationship need not have been proved.”); 21 C.F.R. § 803.3 (adverse event reports address events possibly related to the drug or the device); 21 C.F.R. § 803.16 (adverse event report is not an admission of causation).

Kadane’s analysis of the case goes further astray when he suggests that the facts were strong enough for the case to have survived summary judgment.  Id. at 9.  The Matrixx case was a decision on the adequacy of the pleadings, not of the adequacy of the facts proven.  Elsewhere, Kadane acknowledges the difference between a challenge to the pleadings and the legal sufficiency of the facts, id. at 7 & n.8, but Kadane asserts, without explanation, that the difference is “technical” and does not matter.”  Not true.  The motion to dismiss is made upon receipt of the plaintiffs’ complaint, but the motion for summary judgment is typically made at the close of discovery, on the eve of trial.  The allegations can be conclusory, and they need have only plausible support in other alleged facts to survive a motion to dismiss.  The case, however, must have evidence of all material facts, as well as expert witness opinion that survives judicial scrutiny for scientific validity under Rule 702, to survive a motion for summary judgment, which comes much later in the natural course of any litigated case.

Kadane appears to try to support the conflation of dismissals on the pleadings and summary judgments by offering a definition of summary judgment that is not quite accurate, and potentially misleading:  “The idea behind summary judgment is that, even if every fact alleged by the opposing party were found to be true, the case would still fail for legal reasons.” Id. at 2.  The problem is that at the summary judgment stage, as opposed to the pleading stage, the party with the burden of proof cannot rest upon his allegations, but must come forward with facts, not allegations, to support every essential element of his case.  A plaintiff in a personal injury action (not a securities fraud case), for example, may easily survive a motion to dismiss by alleging medical causal connection, but at the summary judgment stage, that plaintiff must serve a report of an appropriately qualified expert witness, who in turn has presented a supporting opinion, reliably ground in science, to survive both evidentiary challenges and a dispositive motion.

Kadane concludes that the Matrixx decision’s “fact-based consideration” is consistent with a “Bayesian decision-theoretic approach that models how to make rational decisions under uncertainty.”  Id. at 9.  I am 99.99999% certain that Justice Sotomayor would not have a clue about what Professor Kadane was saying.  Although statistical significance may have played no role in the Court’s holding, and in Kadane’s Bayesian decision-theoretic approach, I am 100% certain that the irrelevance of statistical significance to the Court’s and Prof. Kadane’s approaches is purely coincidental.

Federal Rule of Evidence 702 Requires Perscrutations — Samaan v. St. Joseph Hospital (2012)

February 4th, 2012

After the dubious decision in Milward, the First Circuit would seem an unlikely forum for perscrutations of expert witness opinion testimony.  Milward v. Acuity Specialty Products Group, Inc., 639 F.3d 11 (1st Cir. 2011), cert. denied, ___ U.S.___ (2012).  SeeMilwardUnhinging the Courthouse Door to Dubious Scientific Evidence” (Sept. 2, 2011).  Late last month, however, a First Circuit panel of the United States Court of Appeals held that Rule 702 required perscrutation of expert witness opinion, and then proceeded to perscrutate perspicaciously, in Samaan v. St. Joseph Hospital, 2012 WL 34262 (1st Cir. 2012).

The plaintiff, Mr. Samaan suffered an ischemic stroke, for which he was treated by the defendant hospital and physician.  Plaintiff claimed that the defendants’ treatment deviated from the standard of care by failing to administer intravenous tissue plasminogen activator (t-PA).  Id. at *1.  The plaintiff’s only causation expert witness, Dr. Ravi Tikoo, opined that the defendants’ failure to administer t-PA caused plaintiffs’ neurological injury.  Id. at *2.   Dr. Tikoo’s opinions, as well as those of the defense expert witness, were based in large part upon data from a study done by one of the National Institutes of Health:  The National Institute of Neurological Disorders and Stroke rt-PA Stroke Study Group, “Tissue Plasminogen Activator for Acute Ischemic Stroke,” 333 New Engl. J. Med. 1581 (1995).

Both the District Court and the Court of Appeals noted that the problem with Dr. Tikoo’s opinions lay not in the unreliability of the data, or in the generally accepted view that t-PA can, under certain circumstances, mitigate the sequelae of ischemic stroke; rather the problem lay in the analytical gap between those data and Dr. Tikoo’s conclusion that the failure to administer t-PA caused Mr. Samaan’s stroke-related injuries.

The district court held that Dr. Tikoo’s opinion failed to satisfy the requirements of Rule 702. Id. at *8 – *9.  Dr. Tikoo examined odds ratios from the NINDS study, and others, and concluded that a patient’s chances of improved outcome after stroke increased 50% with t-PA, and thus Mr. Samaan’s healthcare providers’ failure to provide t-PA had caused his poor post-stroke outcome.  Id. at *9.  The appellate court similarly rejected the inference from an increased odds ratio to specific causation:

“Dr. Tikoo’s first analysis depended upon odds ratios drawn from the literature. These odds ratios are, as the term implies, ratios of the odds of an adverse outcome, which reflect the relative likelihood of a particular result.FN5 * * * Dr. Tikoo opined that the plaintiff more likely than not would have recovered had he received the drug.”

Id. at *10.

The Court correctly identified the expert witness’s mistake in inferring specific causation from an odds ratio of about 1.5, without any additional information.  The Court characterized the testimonial flaw as one of “lack of fit,” but it was equally an unreliable inference from epidemiologic data to a conclusion about specific causation.

While the Court should be applauded for rejecting the incorrect inference about specific causation, we might wish that it had been more careful about important details.  The Court misinterpreted the meaning of an odds ratio to be a relative risk.  The NINDS study reported risk ratio results both as an odds ratio and as a relative risk.  The Court’s sloppiness should be avoided; the two statistics are different, especially when the outcome of interest is not particularly rare.

Still, the odds ratio is interesting and important as an approximation for the relative risk, and neither measure of risk can substitute for causation, especially when the magnitude of the risk is small, and less than two-fold.  The First Circuit recognized and focused in on this gap between risk and causal attribution in an individual’s case:

“[Dr. Tikoo’s] reasoning is structurally unsound and leaves a wide analytical gap between the results produced through the use of odds ratios and the conclusions drawn by the witness. When a person’s chances of a better outcome are 50% greater with treatment (relative to the chances of those who were not treated), that is not the same as a person having a greater than 50% chance of experiencing the better outcome with treatment. The latter meets the required standard for causation; the former does not.  To illustrate, suppose that studies have shown that 10 out of a group of 100 people who do not eat bananas will die of cancer, as compared to 15 out of a group of 100 who do eat bananas. The banana-eating group would have an odds ratio of 1.5 or a 50% greater chance of getting cancer than those who eschew bananas. But this is a far cry from showing that a person who eats bananas is more likely than not to get cancer.

Even if we were to look only at the fifteen persons in the banana-eating group who did get cancer, it would not be likely that any particular person in that cohort got it from the consumption of bananas. Correlation is not causation, and a substantial number of persons with cancer within the banana-eating group would in all probability have contracted the disease whether or not they ate bananas.FN6

We think that this example exposes the analytical gap between Dr. Tikoo’s methods and his conclusions.  Although he could present figures ranging higher than 50%, those figures were not responsive to the question of causation. Let us take the “stroke scale” figure from the NINDS study as an example. This scale measures the neurological deficits in different parts of the nervous system. Twenty percent of patients who experienced a stroke and were not treated with t-PA had a favorable outcome according to this scale, whereas that figure escalated to 31% when t-PA was administered.

Although this means that the patients treated with t-PA had over a 50% better chance of recovery than they otherwise would have had, 69% of those patients experienced the adverse outcome (stroke-related injury) anyway.FN7  The short of it is that while the odds ratio analysis shows that a t-PA patient may have a better chance of recovering than he otherwise would have had without t-PA, such an analysis does not show that a person has a better than even chance of avoiding injury if the drug is administered. The odds ratio, therefore, does not show that the failure to give t-PA was more likely than not a substantial factor in causing the plaintiff’s injuries. The unavoidable conclusion from the studies deemed authoritative by Dr. Tikoo is that only a small number of patients overall (and only a small fraction of those who would otherwise have experienced stroke-related injuries) experience improvement when t-PA is administered.”

*11 and n.6 (citing Milward).

The court in Samaan thus suggested, but did not state explicitly, that the study would have to have shown better than a 100% increase in the rate of recovery for attributability to have exceeded 50%.  The Court’s timidity is regrettable. Yes, Dr. Tikoo’s confusing the percentage increased risk with the percentage of attributability was quite knuckleheaded.  I doubt that many would want to subject themselves to Dr. Tikoo’s quality of care, at least not his statistical care.  The First Circuit, however, stopped short of stating what magnitude increase in risk would permit an inference of specifc causation for Mr. Samaan’s post-stroke sequelae.

The Circuit noted that expert witnesses may present epidemiologic statistics in a variety of forms:

“to indicate causation. Either absolute or relative calculations may suffice in particular circumstances to achieve the causation standard. See, e.g., Smith v. Bubak, 643 F.3d 1137, 1141–42 (8th Cir.2011) (rejecting relative benefit testimony and suggesting in dictum that absolute benefit “is the measure of a drug’s overall effectiveness”); Young v. Mem’l Hermann Hosp. Sys., 573 F.3d 233, 236 (5th Cir.2009) (holding that Texas law requires a doubling of the relative risk of an adverse outcome to prove causation), cert. denied, ___ U.S. ___, 130 S.Ct. 1512, 176 L.Ed.2d 111 (2010).”

 Id. at *11.

Although the citation to Texas law with its requirement of a doubling of a relative risk is welcome and encouraging, the Court seems to have gone out of its way to muddle its holding.  First, the Young case involved t-PA and a claimed deviation from the standard of care in a stroke case, and was exactly on point.  The Fifth Circuit’s reliance upon Texas substantive law left unclear to what extent the same holding would have been required by Federal Rule of Evidence 702.

Second, the First Circuit, with its banana hypothetical, appeared to confuse an odds ratio with a relative risk.  The odds ratio is different from a relative risk, and typically an odds ratio will be higher than the corresponding relative risk, unless the outcome is rare.  See Michael O. Finkelstein & Bruce Levin, Statistics for Lawyers at 37 (2d ed. 2001). In studies of medication efficacy, however, the benefit will not be particularly rare, and the rare disease assumption cannot be made.

Third, risk is not causation, regardless of magnitude.  If the magnitude of risk is used to infer specific causation, then what is the basis for the inference, and how large must the risk be?  In what way can epidemiologic statistics be used “to indicate” specific causation?  The opinion tells us that Dr. Tivoo’s reliance upon an odds ratio of 1.5 was unhelpful, but why?  The Court, which spoke so clearly and well in identifying the fallacious reasoning of Dr. Tivoo, faltered in identifying what use of risk statistics would permit an inference of specific causation in this case, where general causation was never in doubt.

The Fifth Circuit’s decision in Young, supra, invoked a greater than doubling of risk required by Texas law.  This requirement is nothing more than a logical, common-sense recognition that risk is not causation, and that small risks alone cannot support an inference of specific causation.  Requiring a relative risk greater than two makes practical sense despite the apoplectic objections of Professor Sander Greenland.  SeeRelative Risks and Individual Causal Attribution Using Risk Size” (Mar. 18, 2011).

Importantly, the First Circuit panel in Samaan did not engage in the hand-waving arguments that were advanced in Milward, and stuck to clear, transparent rational inferences.  In footnote 6, the Samaan Court cited its earlier decision in Milward, but only with double negatives, and for the relevancy of odds ratios to the question of general causation:

“This is not to say that the odds ratio may not help to prove causation in some instances.  See, e.g., Milward v. Acuity Specialty Prods. Group, Inc., 639 F.3d 11, 13–14, 23–25 (1st Cir.2011) (reversing exclusion of expert prepared to testify as to general rather than specific causation using in part the odds ratio).”

Id. at n.6.

The Samaan Court went on to suggest that inferring specific causation from the magnitude of risk was “theoretically possible”:

Indeed, it is theoretically possible that a particular odds ratio calculation might show a better-than-even chance of a particular outcome. Here, however, the odds ratios relied on by Dr. Tikoo have no such probative force.

Id. (emphasis added).  But why and how? The implication of the Court’s dictum is that when the risk ratio is small, less than or equal to two, the ratio cannot be taken to have supported the showing of “better than even chance.” In Milward, one of the key studies relied upon by plaintiff’s expert witness reported an increased risk of only 40%.  Although Milward presented primarily a challenge on general causation, the Samaan decision suggests that the low-dose benzene exposure plaintiffs are doomed, not by benzene, but by the perscrutation required by Rule 702.

Ethics and Daubert: The Scylla and Charybdis of Medical Monitoring

February 1st, 2012

Build a courtroom and they will come. The floodgates argument, all too quickly rejected by the judiciary, proved all too true in West Virginia. West Virginia built a courtroom that would entertain multiple claims from virtually every West Virginian. This jurisprudential hospitality offers medical monitoring that requires no predicate present injury. Bower v. Westinghouse Electric Corp., 522 S.E.2d 424 (W.Va. 1999).

Everyone is exposed to hazardous substances and to medications with potential side effects. In West Virginia, almost everyone is a potential plaintiff in a medical monitoring case.

Universal health care may be attainable, after all, funded by the manufacturers of predominately beneficial products. Almost heaven West Virginia, indeed. Type 2 diabetes mellitus, or adult-onset diabetes, is a devastating disease that results from uncontrolled blood sugars. The medical complications of diabetes are extensive and well known: blindness, gangrene, kidney failure, heart attack, stroke, liver disease, and others. The costs of this medical care are staggering, and diabetics are among the neediest patients in our health care system. Imagine if the “compensation goals” of the tort system could be subverted to provide medical monitoring to diabetic patients. If possible anywhere, it would seem West Virginia would be the most likely candidate.

Between March 1997 and March 2000, many Type 2 diabetics achieved control of their blood sugars with the help of a new oral medication, Troglitazone (Rezulin®).  Troglitazone modifies the Type 2 diabetic patient’s resistance to insulin. The drug effectively reduces blood sugar, and it avoids the need for exogenous insulin. Most life-saving drugs have side effects, and Troglitazone is no exception. Physicians, knowledgeable about Troglitazone’s efficacy and its potential for rare, idiosyncratic liver toxicity, prescribed the drug to help their patients gain control over their blood sugar levels and to avoid the serious complications of diabetes. In March 2000, the manufacturer of Troglitazone voluntarily withdrew the drug from the market. Adverse publicity over liver toxicity and the availability of two other more recent glitazones, which initially had the appearance of a safer adverse event profile, had shifted the risk-benefit balance against Troglitazone.

No one can be surprised that Rezulin plaintiffs sought class certification in West Virginia state court; nor can anyone, in view of Bower, be surprised that asymptomatic plaintiffs sought medical monitoring as a remedy, within the context of the class action. Observers unfamiliar with the weakness of the Rezulin plaintiffs’ scientific proofs might, however, be surprised at the plaintiffs’ failure, initially at the trial court level, to win class certification in West Virginia, for a medical monitoring class. In re West Virginia Rezulin Litigation, W.Va. Cir.Ct., Civil Action No. 00-C-1180H, Amended Order Denying Class Certification (Dec. 12, 2001) (Hutchison, J.), 2001 WL 1818442 (Dec 13, 2001).

The West Virginia trial court’s rejection of the proposed Rezulin medical monitoring class is remarkable for many reasons. Some commentators regard West Virginia law as the outer limits of medical monitoring jurisprudence.  In the Rezulin case, however, Judge John Hutchison delivered a thorough, analytical opinion, which demonstrated that the liberal West Virginia criteria for a medical monitoring remedy cannot be satisfied as easily as once thought. Among the notable holdings were the trial court’s insistence that:

(1) the monitoring proponents adduce epidemiologic evidence that the exposure at issue can actually cause the latent injury for which monitoring is sought;

(2) the proponents of monitoring identify highly sensitive tests, which when deployed on the exposed population that has a relatively high prevalence of the latent injury, will have a high predictive value; and

(3) the proposed monitoring will allow for early preventive care.

In determining whether the class plaintiffs had met the criteria for medical monitoring, Judge Hutchison did not face any significant evidentiary gatekeeping responsibility. The trial court did not have to ponder the contours of any reliable epidemiologic studies. The court found no epidemiologic studies to show that Rezulin can cause latent injury months or years after the drug is discontinued.

Similarly, the court did not have to delve into any evidentiary thicket of contradictory scientific proof to determine whether the proposed medical monitoring program was based upon reliable scientific and medical methods. The court found that most of the proposed tests had low sensitivity, and that there were no diagnostic tests that can determine whether any liver injury was caused by Rezulin. Given the many other causes of liver diseases among the plaintiff class members, there was no evidence of any prevalence of latent injury from Rezulin. Without an assessment of prevalence of latent injury, any proposed test would have little or no positive predictive value. The proposed program failed for lack of substantial evidentiary support.

The court was further impressed by the riskiness of the proposed monitoring program. The proposed tests, lacking sensitivity and specificity, were likely to result in many “false positives,” which in turn would lead to liver biopsies.  (Indeed, false positives would likely swamp any true positives if any there should be). Liver biopsies, however, are painful, invasive, and carry a small, but definite, risk of death. Furthermore, the court found that the proposed tests would not facilitate medical interventions that could prevent or resolve the detected problem.

This failure to obtain class certification for medical monitoring is noteworthy for more than the narrow case holdings. There is intriguing obiter dictum. The court noted that one of the plaintiffs’ expert witnesses admitted that the proposed monitoring program was an “experiment.” The court found this admission directly relevant to the plaintiffs’ failure to produce epidemiologic evidence that the substance at issue could actually cause latent injury. Apparently, the plaintiffs’ witness was advocating implementation of the monitoring program so it might yield the evidence that the class must proffer before it could obtain the monitoring remedy. The court readily dismissed this Alice in Wonderland insistence upon “[s]entence first—verdict afterwards.” The court showed little patience for the “stuff and nonsense” of trying to satisfy the criterion of epidemiologic evidence with the anticipated results that would come from the proposed monitoring program itself.

Implicit in the trial court’s rejection of evidentiary bootstrapping is a larger, ethical concern. There is something unsettling about a court-ordered medical monitoring program that is an “experiment.” Class certification decisions are complicated enough without having to endorse experimentation on human beings. Perhaps the suggestion of human experimentation chilled any residual enthusiasm for the notion that medical monitoring might otherwise be a suitable judicial remedy for achieving corrective justice in a mass tort case.

And yet there is an “experimental” aspect to many, if not most, proposed monitoring programs. Little or no clinical experience is available to support the claimed benefits of many proposed large, lifelong monitoring regimes. Indeed, such programs are not wholly benign. The potential harms of monitoring, some of which were acknowledged in Judge Hutchison’s opinion, are significant.

The imposition of potentially harmful monitoring should, indeed, trouble our courts and cause their reticence in embracing monitoring as a remedy. Courts need to confront the ethical implications that flow from the experimental nature of many medical monitoring proposals.

Proposals for monitoring differ from expert witness opinion that is typically offered in personal injury cases involving present injuries. Physician witnesses, at the request of the parties, usually examine claimants, evaluate and diagnose their conditions, and opine about prognosis and etiology. Although such witnesses use their medical experience, training, and knowledge, they generally are not acting within the context of a patient-physician relationship. Adams v. Harron, 191 F.3d 447, 1999 WL 710326 (4th Cir. 1999). In the usual personal injury case, physician witnesses are not advocating medical interventions; at most, they are endorsing or criticizing the reasonable medical necessity of medical plans of treating physicians.  In medical monitoring class actions, however, physician expert witnesses advocate medical interventions for people they have often never met and have never evaluated.

Recommendations for preventive health measures carry risks of harm, and these risks must provoke ethical scrutiny of the proposed monitoring. The offering of an opinion that a plaintiff, or a class of plaintiffs, should receive medical monitoring is the practice of medicine. As part of medical practice, the presentation of such opinions is subject to ethical constraints, which courts should observe and foster. Medico-legal opinions that recommend preventive interventions represent a significant involvement in the claimant’s actual medical care. Screening or monitoring recommendations must acknowledge and avoid the highly individualized risks of harm and the essential need for informed consent to protect individual autonomy.

Physicians who prepare medical monitoring litigation plans cannot absolve themselves of ethical and professional responsibility by disclaiming the existence of physician-patient relationships. Such physicians are not practicing mere courthouse medicine; they are engaged in medical practice, as defined by the American Medical Association, AMA Policy H-265.993, and in the sense that they are seeking to control future medical interventions for the class members.  Physicians who propose medical monitoring or screening for claimants thus operate under the ethical constraints of avoiding harm, providing benefits, and respecting individual patient autonomy. The medical community recognizes that good intentions notwithstanding, monitoring can be harmful. “[P]reventive therapies can give rise to anticipatory anxiety, side effects, the stress of false-positive results and an unhealthy preoccupation with disease.” Huston, “The Perils of Prevention,” 154 Canadian Med. Ass’n J. 1463 (1996). Other potential adverse effects of monitoring include deriving false assurances of health and being labeled as “sick.” Marshall, “Prevention. How Much Harm? How Much Benefit? 3. Physical, Psychological and Social Harm,” 155 Canadian Med. Ass’n J. 169 (1996).

Furthermore, some screening programs will detect true-positive results with little or no clinical significance.  For example, in cancer screening, some nodules detected will be benign. Other nodules may be extremely indolent malignancies, which would never become aggressive, metastatic growths. Indeed, such masses, picked up in screening, might regress before they would have been otherwise detectable. Screening programs must come to grips with the vagaries of the diseases and conditions that are the subject of the monitoring. The potential for harm, from monitoring, may be increased by the litigation setting, in which people are encouraged to become invested in illness seeking behaviors.

Given the potential for harm, physician witnesses who advocate monitoring face ethical and evidentiary burdens to establish the efficacy and benefit of the planned screening. At a minimum, class members will have to be properly advised, and will have to be given informed consent. The process of obtaining consent must accommodate the intensely personal and individualized judgments about the risks of monitoring.

Well-established criteria for evaluating public health interventions are available and employed by such agencies and groups as the United States Preventive Task Force, the Canadian Task Force on the Periodic Health Examination, the Cochrane Collaboration, and others.  The existence of generally accepted evaluative criteria has obvious implications for determining the admissibility of monitoring proposals under either Daubert or Frye standards. Expert witnesses, in this ethically sensitive area, must be held to the same intellectual rigor that would be employed to evaluate monitoring or screening programs in the field of public health. Pitfalls, fallacies, and methodological error are abundant in the field of preventive medicine. Marshall, “Prevention. How Much Harm? How Much Benefit? 2. Ten Potential Pitfalls in Determining the Clinical Significance of Benefits,” 154 Canadian Med. Ass’n J. 1837 (1996). Even well-intentioned advice, such as counseling routine mammography in women, has been the subject of heated controversy and intense methodological debate. Ernster, “Mammograms and Personal Choice,” The New York Times (Feb. 14, 2002).   Courts must acknowledge that if a proposed preventive program does not satisfy generally accepted criteria for medical interventions and does not have proven benefits that clearly outweigh the potential harms, medical monitoring becomes a court-sanctioned human experiment.

The guiding principles and corollaries for human experimental research can be found in several sources, including The Nuremberg Code, Permissible Medical Experiments, World Medical Association, “Declaration of Helsinki’s Ethical Principles for Medical Research Involving Human Subjects,” 284 J. Am. Med. Ass’n 3043 (Dec. 20, 2000), as restated on several occasions, regulations of the Food and Drug Administration, Protection of Human Subjects, 21 C.F.R. § 50.25; and the Department of Health and Human Services, 45 C.F.R. § 46.

Informed consent is the absolute requirement for any human medical experimentation. Regulations and guidelines of various federal and state agencies and medical organizations, however, place further limitations on the course of permissible experimental design.  The Declaration of Helsinki, for instance, requires that the research design be clearly set out in an experimental protocol, which has been approved by an independent ethical review committee. The proposed medical research

“must conform to generally scientific principles, [and] be based on a thorough knowledge of the scientific literature….”

Declaration of Helsinki, ¶11 (2000). Permissible Medical Experiments, supra. Daubert and Frye thus become ethical imperatives, as well as legal requirements, before any serious consideration can be given to a medical monitoring program.

In all likelihood, no court, if it really thought about the matter, would want to serve as an Institutional Review Board, and to sit in judgment of an experimental protocol. The realization that the proposed remedy is itself an experiment should suffice to quash any advocacy for the result. Indeed, an awareness of the ethical problems entailed by poorly supported medical monitoring programs must guide and propel courts to be vigilant in their gatekeeping responsibilities.  Much of the earlier case law on monitoring developed before the principles and implications of Daubert could be realized in monitoring cases, and these older judgments must be questioned in the light of these ethical and evidentiary concerns.

Judge Hutchison’s decision to deny certification for a Rezulin medical monitoring class obviated consideration of the ethical and evidentiary problems posed by monitoring remedies. The clear absence of proof to support the remedy for the Rezulin plaintiffs avoided debate over how to protect the informed consent process when the personal perception of the risks of monitoring will be perceived differently by each class member.

The paradisiacal Appalachian dream, however, did not last very long.

The Supreme Court of West Virginia did not appear to be concerned by the ethics of human experimentation or the need for showing a basis in evidence for the reliability or accuracy of screening tests.  Chief Justice Starcher, writing for a unanimous court, reversed and remanded the case to proceed as a class action.  The Supreme Court’s opinion was a mechanical recitation of class action rules, interpreted to disallow any preliminary inquiry into the merits of the suit. In re West Virginia Rezulin Litig., 585 S.E.2d 52 (W.Va. 2003).  The word “ethics” does not appear in the Supreme Court’s opinion. The Nuremberg Code was nowhere in sight.

Perhaps most medical monitoring class action battles are now behind us, given that federal courts have come to their senses and have generally disallowed class actions for this remedy.  The cases on the book, however, represent ethically dubious judgments, which call for condemnation from the medical and legal community.  Courts must take stock of the certainty that many medical monitoring schemes will produce far more false positive cases than true positive cases, and widespread fear, anxiety, and harm from unnecessary medical interventions.  See generally Christopher P. Guzelian, Bruce E. Hillner, and Philip S. Guzelian, “A Quantitative Methodology for Determining the Need for Exposure-Prompted Medical Monitoring,” 79 Indiana L. J. 57 (2004).

[An earlier version of this post was published under the same title in Industrywide Liability News (Spring 2002)]

The opinions, statements, and asseverations expressed on Tortini are my own, or those of invited guests, and these writings do not necessarily represent the views of clients, friends, or family, even when supported by good and sufficient reason.