MARCH 14, 2005
Two Courts: A Differential Diagnosis Without a Medical
Basis Is a Prescription for Failure
Tenth Circuit - Experts Must Address Negative Epidemiology
The U.S. Court of Appeals for the Tenth Circuit recently upheld excluding the testimony of
two experts proffered by a plaintiff because the experts “ignored or discounted” all contrary
epidemiology studies that found no reliable link between silicon breast implants and systemic
disease and did not offer a reliable basis for their contrary opinion. Norris v. Baxter Healthcare
Corp., 10th Cir., No. 03-1471, 2/8/05. The consequence of this decision was that summary
judgment for the defendant was affirmed.
Although epidemiological evidence may not always be required in a toxic tort case, the court
held that, “where there is a large body of contrary epidemiological evidence,” an expert must
“at least address [the contrary evidence] with evidence that is based on medically reliable and
scientifically valid methodology.” Because plaintiff’s experts could not summon any
supporting evidence summary judgment was affirmed in favor of the manufacturer.
Plaintiff’s experts relied solely on differential diagnosis and case studies to support their belief
that silicone gel breast implants can cause systemic disease. The epidemiological studies,
however, were “flatly contrary” to all of the evidence set forth by the experts. Because the
experts did not address the contrary epidemiological proof, the court concluded their
methodology was not valid under Daubert. The court explained, “[w]e are unable to find a
single case in which differential diagnosis that is flatly contrary to all of the available
epidemiological evidence is both admissible and sufficient to defeat a defendant’s motion for
summary judgment.”
Plaintiff Claims That a Silicone Gel Breast Implant Caused Her Systemic Disease
In 1970, plaintiff underwent bilateral breast augmentation surgery with silicone gel implants.
Four years later, the left implant was removed and replaced with another silicone gel implant.
In 1978, plaintiff had both implants replaced after a rupture of her right implant. Dr. Vasey,
one of plaintiff’s experts, diagnosed plaintiff as having connective tissue disease caused by
silicone that leaked from breast implants.
Plaintiff proffered two experts, both highly credentialed in the field of rheumatology. Both
conducted physical examinations of the plaintiff and both opined that silicone gel breast
implants could cause systemic autoimmune diseases. The experts, however, did not rely on
any epidemiological studies. Instead, they relied on individual case studies and differential
diagnoses for their opinions that silicone gel breast implants can cause systemic disease. The
experts completely ignored the numerous epidemiological studies that do not establish a link
between silicone gel breast implants and any systemic disease. Without explanation, they
opined that plaintiff’s particular disease had either “escaped study” or that “no study ha[d]
been designed to specifically address atypical connective tissue disease.”
Colorado District Court - Summary Judgment for Baxter
The U.S. District Court for the District of Colorado granted summary judgment in favor of
Baxter Healthcare, explaining that in silicone breast implant litigation plaintiffs must show
both general and specific causation. While epidemiological studies are not the only admissible
evidence to prove general causation, the district court concluded that plaintiff needed
epidemiological evidence to overcome Baxter’s motion for summary judgment in this case.
The court noted that Baxter had proffered a significant body of epidemiology to support its
conclusion that silicone implants do not cause systemic disease. Medical science, through
epidemiological studies, has shown that a causal connection between silicone breast implants
and systemic disease does not exist. Plaintiff’s experts’ contrary conclusions based on
differential diagnosis and case studies, the court concluded, were not scientifically reliable and,
hence, inadmissible.
On appeal, the Tenth Circuit agreed, stressing that “where there is a large body of contrary
epidemiological evidence, it is necessary to at least address [the contrary studies] with evidence
that is based on medically reliable and scientifically valid methodology.” In addressing the
contrary epidemiology, the court cautioned that Daubert considerations must also be accounted
for, including whether the expert’s opinions are peer-reviewed, are developed independent of
litigation, and are generally accepted by the relevant scientific community.
The Tenth Circuit also advised that differential diagnosis is only an appropriate method to
demonstrate specific causation when general causation has already been established. As the
Tenth Circuit properly explained, a differential diagnosis is one of exclusion. A physician
begins by ruling in all possible causes of a patient’s signs and symptoms. To be ruled in, there
must be proof that the substance or pathogen in question has been shown to cause the
particular disease in humans. After “ruling in” all potential causes, the physician then begins
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to rule out potential causes, either through testing or exposure opportunity. If any known
cause cannot be ruled out, then the physician may conclude that the substance or pathogen
which could not be ruled out is the cause-in-fact of the patient’s condition.
A New York District Court Explores a Corollary
The District Court for the Southern District of New York, in In re: Rezulin Products Liability
Litigation, 2004 U.S. Dist. LEXIS 25038, 12/9/04, held that an expert’s opinion of causation,
based on differential diagnosis, was inadmissible because the expert could not point to any
studies published in the medical or scientific literature that demonstrated the use of the
medication in question was generally capable of causing the injury in question. While
recognizing the qualifications of the witness, the court focused on whether there was a reliable
scientific or medical basis for the expert’s opinion. Without the general causation studies to
“rule in” the exposure to the medication as a cause of the condition at issue, the specific
causation relationship could not be made, avoiding the fallacy that often plagues this
discussion.
Conclusion
Taken together, these cases are channel markers for a coherent discussion about the
admissibility of expert opinions based upon purported differential diagnoses:
1.
There must be support in the medical and scientific literature, preferably
epidemiological studies, that support the general cause and effect relationship
between exposure and condition;
2.
To disregard significant contrary epidemiological support for the lack of a
causal relationship, there must be reliable medical evidence, preferably an
opposing study, on which the expert can rely; and
3.
Finally, the talismanic use of the term “differential diagnosis” is not sufficient
to overcome the medical, scientific, and logical shortcomings of the plaintiff’s
proof.
We welcome your questions and comments. For more information, please contact:
Joseph J. Leghorn
Vivian M. Quinn
Samuel Goldblatt
Fred Kelly
Joseph Ortego
Benjamin R. Dwyer
Jacob J. Herstek
Tracey B. Ehlers
[email protected]
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