Under Texas law, doctor’s opinions regarding causation of injuries or diseases are subject to the rules regarding reliability of expert opinions set forth in the Texas Supreme Court case, E.I. duPont & Co. v. Robinson, 923 S.W.2d 549 (Tex. 1995). Any doubt about this was put to rest by the Supreme Court in Transcontinental Insurance Co. v. Crump, 330 S.W.3d 211 (Tex. 2010). In Crump, the Court was faced with a causation question involving the death of an employee (a transplant recipient who was infection susceptible because of anti-rejection drugs) after an on the job injury, which was a wound that became infected, ultimately resulting in his death. The treating doctor opined that the wound had become infected because of the drugs lowering resistance.
The treating doctor used the time honored method of medical diagnosis referred to as “differential diagnosis”. The Court held that even this method is subject to the applicable Robinson factors for determining reliability. The Court stated that the method is the “basic method of internal medicine and enjoys widespread acceptance in the medical community.” “Generally speaking, when properly conducted the technique has important non-judicial uses, is generally accepted as valid by the medical community, and has been subjected to use, peer review, and testing.”
The Court did state that “opinions formed solely for the purpose of testifying are more likely to be biased toward a particular result.” The Court stated that it should be determined whether there are any significant analytical gaps in the expert’s opinions that undermine its reliability. The Court noted that “in some case, a physician’s differential diagnosis may be too dependent upon the physician’s subjective guesswork or produce too great a rate of error- for example, when there are several consistent, possible causes for a particular set of symptoms.” “An expert’s failure to rule out alternative causes of an incident may render his opinion unreliable.” “An expert who is trying to find a cause of something should carefully consider alternative causes.” However, the Court also stated that, “…a medical causation expert need not disprove or discredit every possible cause other than the one espoused by him. Few expert opinions would be reliable if the rule were otherwise. Still, if evidence presents other plausible causes of the injury or condition that could be negated, the [proponent of the testimony] must offer evidence excluding those causes with reasonable certainty.”
In the Crump case, the Court held that Crump adequately excluded the other plausible causes raised by the evidence. The defense expert’s opinion was that Crump’s death was unrelated to the work related injury and that he would have died anyway from the infection regardless of the injury. The defense expert testified that Crump died from a combination of kidney failure, cirrhosis of the liver, and a fungal infection exacerbated by preexisting diabetes and the use of immunosuppresant drugs. The Court acknowledged that this was a plausible other cause of Crump’s death. But, the Court significantly took into account the fact that Crump was generally in good health before his injury at work, and that within days after the injury he contracted an infection at the site of the injury. The Court considered and gave great weight to Crump’s doctor’s opinion based on his experience and training with immunosupressed patients and direct dealings with Crump. Based on this, the Court concluded that Crump’s doctor medical causation opinion provided a cause that excluded, with reasonable medical certainty, the defense’s suggested causes of death. The Court stated that, “the evidence was not conclusive, but it was not required to be. It was sufficiently reliable to be considered by the jury. Once [the treating doctor] effectively responded to [the defense] other plausible casues of death with reliable testimony, the question was no longer one of legal sufficiency, but one of competing evidence to be weighed by the jury.”
The Court also used the factor from the Gammill case (972 S.W.2d at 727) of whether there was too great of an “analytical gap” between the data and the expert’s opinion. The gap in the expert’s analysis is whether the expert failed to show how his observations supported his conclusions. In applying this test to the Crump case, the Court stated that there was not too great a gap because of the treating doctor’s “techniques in assessing” Crump (there must be a failure to show how his observations supported his conclusions). The Court stated that Crump’s doctor directly treated or oversaw Crump’s treatment. He took cultures from the wound site and performed surgery to diagnose and to assist healing of the wound. The cultures allowed the observation that Crump’s wound was infected with the same agent as the infectious agent that had become systemic in Crump. Further, the doctor observed that Crump-despite being a kidney transplant recipient with diabetes- had no medical history of organ problems from the period after the transplant in 1975 until after the work related injury in 2000. The Court stated that temporal proximity alone does not meet the standard of scientific reliability and does not, by itself, support an inference of medical causation. “Nevertheless, when combined with other causation evidence, evidence that conditions exhibited themselves or were diagnosed shortly after an event may be probative in determining causation.”
Therefore, the Court stated that, “we cannot conclude that there was ‘too great an analytical gap’ between the observed data and the proferred opinion…At this point, any ‘gaps’ that remain between the data and the conclusion drawn from it go to the weight of [the doctor’s] testimony– not its reliability.” The Court then held that Crump’s doctor’s opinion was based on a sufficiently reliable foundation under the standards set out in Robinson and Gammill and was admissible at trial as evidence to prove that the job injury was a producing cause of Crump’s death.