Opinion ID: 2829186
Heading Depth: 1
Heading Rank: 2

Heading: Legal Sufficiency of Expert Testimony

Text: Producing cause was the only issue submitted to the jury at trial. Because this is an appeal of a Workers’ Compensation Commission award of death benefits, Transcontinental acknowledges that it had the burden to prove that the May 2000 injury was not a producing cause of Crump’s death. See Tex. Lab. Code § 410.303 (“The party appealing the decision [of the appeals panel] on an issue [regarding compensability or eligibility for or the amount of income or death benefits] has the burden of proof by a preponderance of the evidence.”); Morales v. Liberty Mut . Ins. Co. , 241 S.W.3d 514, 516–17 (Tex. 2007) (discussing the avenues of judicial review). Thus, Transcontinental, the insurance carrier, was the plaintiff at trial; Crump, the claimant, was the defendant. The trial court asked the jury whether Crump’s injury was a producing cause of his death, but to properly allocate the burden of proof, the court instructed the jury to answer “yes” unless they found by a preponderance of the evidence that the answer should be “no.” In answering “yes,” the jury thus failed to find that Crump’s injury did not cause his death. On appeal, Transcontinental asserts that it conclusively established the lack of causality and is therefore entitled to judgment in its favor as a matter of law. At trial, Transcontinental’s expert, Hunt, testified that the natural complications of being immunosuppressed for twenty-five years had caused Crump’s death—not the May 2000 injury. Crump’s expert and treating physician, Daller , testified that the wound site of the May 2000 work-related injury became infected, the infection caused Crump’s already-weakened organs to fail, and his organ failure in turn caused his death. Transcontinental objected to the admission of Daller’s testimony on the ground that it was unreliable, but the trial court overruled that objection. Here, Transcontinental reasserts that Daller’s testimony was unreliable and therefore legally insufficient evidence of causation. Without Daller’s testimony, Transcontinental argues, Hunt’s testimony establishes the lack of causation. Accordingly, we must decide whether Daller’s testimony was reliable and, if so, whether it was some evidence of causation. “An expert witness may testify regarding ‘scientific, technical, or other specialized’ matters if the expert is qualified and if the expert’s opinion is relevant and based on a reliable foundation.” Mack Trucks, Inc. v. Tamez , 206 S.W.3d 572, 578 (Tex. 2006) (citing Tex. R. Evid. 702). In determining whether expert testimony is reliable, a court should consider the factors we set out in E.I. du Pont de Nemours & Co. v. Robinson , 923 S.W.2d 549, 557 (Tex. 1995), 2 as well as the expert’s experience, knowledge, and training. See Gammill v. Jack Williams Chevrolet, Inc. , 972 S.W.2d 713, 726–27 (Tex. 1998) (deeming expert testimony based on the latter considerations unreliable when “there is simply too great an analytical gap between the data and the opinion proffered” (citing Gen. Elec. Co. v. Joiner , 552 U.S. 136, 146 (1997)); see also Tex. R. Evid. 702 (providing for witnesses qualified as experts “by knowledge, skill, experience, training, or education”). [I]n very few cases will the evidence be such that the trial court’s reliability determination can properly be based only on the experience of a qualified expert to the exclusion of factors such as those set out in Robinson , or, on the other hand, properly be based only on factors such as those set out in Robinson to the exclusion of considerations based on a qualified expert’s experience. Whirlpool Corp. v. Camacho , 298 S.W.3d 631, 638 (Tex. 2009); see also Mack Trucks , 206 S.W.3d at 579 (“[T]he criteria for assessing reliability must vary depending on the nature of the evidence.”). Here, we are considering the reliability of a treating physician’s opinion based on a particular diagnostic methodology—differential diagnosis. This is a routine diagnostic method used in internal medicine whereby a treating physician formulates a hypothesis as to likely causes of a patient’s presented symptoms and eliminates unlikely causes by a deductive process of elimination. See, e.g. , Coastal Tankships , U.S.A., Inc. v. Anderson , 87 S.W.3d 591, 604–05 & n.24 (Tex. App.—Houston [1st Dist.] 2002, pet. denied) (en banc) (“[Differential diagnosis] is a clinical process whereby a doctor determines which of several potential diseases or injuries is causing the patient’s symptoms by ruling out possible causes—by comparing the patient’s symptoms to symptoms associated with known diseases, conducting physical examinations, collecting data on the patient’s history and illness, and analyzing that data—until a final diagnosis for proper treatment is reached.”). If the physician’s treatment of the suspected cause alleviates the patient’s symptoms, the disease or condition treated can be said to have been the internal cause of the eliminated symptoms. See id. If the patient’s symptoms remain after treatment of the suspected disease or condition, the physician rules out the suspected disease or condition as the internal cause of the patient’s symptoms and formulates a new hypothesis as to the possible culprit. See id. Crump asserts that because differential diagnosis is a reliable medical technique, the application of the Robinson factors is tempered, or less strict, when a treating physician using that technique is involved. This is the approach adopted by the court of appeals below, which refused to apply Robinson at all. See 274 S.W.3d at 96–97. We have held the opposite to be true: “[T]he relevance and reliability requirements of Rule 702 [apply] to all expert evidence offered under that rule, even though the criteria for assessing relevance and reliability must vary, depending on the nature of the evidence.” Gammill , 972 S.W.2d at 727; see also Camacho , 298 S.W.3d at 638. The mere fact that differential diagnosis was used does not exempt the foundation of a treating physician’s expert opinion from scrutiny—it is to be evaluated for reliability as carefully as any other expert’s testimony. Both the Robinson and Gammill analyses are appropriate in this context. See generally Guinn v. AstraZeneca Pharm. LP , 602 F.3d 1245, 1254 (11th Cir. 2010) (per curiam ); Meister v. Med. Eng’g Corp. , 267 F.3d 1123, 1129 (D.C. Cir. 2001); Westberry v. Gislaved Gummi AB , 178 F.3d 257, 263–65 (4th Cir. 1999); Heller v. Shaw Indus., Inc. , 167 F.3d 146, 153–54 (3d Cir. 1999); Moore v. Ashland Chem. Inc. , 151 F.3d 269, 275–78 (5th Cir. 1998) (en banc). Several of the Robinson factors apply to differential diagnosis as a method or technique, as well as its application and the conclusions reached in a particular case. “Differential diagnosis 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.” Coastal Tankships , 87 S.W.3d at 604 (citations omitted). While these endorsements of the technique may hold “generally,” we cannot say that they will always apply in every case in which a treating physician bases his opinion on differential diagnosis. Here, though, Daller’s diagnostic methodology certainly had non-judicial uses in that it was used to treat Crump, write prescriptions, and perform surgery. Cf. Robinson , 923 S.W.2d at 559 (“[O]pinions formed solely for the purpose of testifying are more likely to be biased toward a particular result.”). Hunt, Transcontinental’s expert, acknowledged that differential diagnosis was used to treat Crump. Although Hunt would have reached different conclusions regarding Crump’s infection, he stated that he agreed with the treatment methodology Daller employed. See Robinson , 923 S.W.2d at 557 (noting that the Robinson reliability inquiry focuses “solely on the underlying principles and methodology, not on the conclusions they generate”); cf. TXI Transp. Co. v. Hughes , 306 S.W.3d 230, 235 (Tex. 2010) (“Rather than focus entirely on the reliability of the underlying technique used to generate the challenged opinion, as in Robinson , we have found it appropriate . . . [to] determine whether there are any significant analytical gaps in the expert’s opinion that undermine its reliability.”) ( citations omitted). Moreover, there is no practical way peers could conduct objective, randomized experiments to test the validity of Daller’s specific conclusion regarding Crump’s injury. Thus, these factors support the reliability of Daller’s expert testimony in this case. Moving to the other Robinson factors, we note that, in some cases, 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. Related to these factors, Transcontinental contends that Daller’s diagnostic technique is not reliable because he did not exclude the other possible causes of Crump’s death with reasonable medical probability. See TXI Transp. Co. , 306 S.W.3d at 237 (“An expert’s failure to rule out alternative causes of an incident may render his opinion unreliable.”); Robinson , 923 S.W.2d at 559 (“An expert who is trying to find a cause of something should carefully consider alternative causes. [An expert’s] failure to rule out other causes of the damage renders his opinion little more than speculation.” ( citation omitted)); see also Burroughs Wellcome Co. v. Crye , 907 S.W.2d 497, 500 (Tex. 1995) (“[T]o constitute evidence of causation, an expert opinion must rest in reasonable medical probability.”). Yet a medical causation expert need not “ disprov [e] or discredit[ ] every possible cause other than the one espoused by him.” Viterbo v. Dow Chem. Co. , 826 F.2d 420, 424 (5th Cir. 1987). 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.” Merrell Dow Pharm., Inc. v. Havner , 953 S.W.2d 706, 720 (Tex. 1997) (emphases added); see also Robinson , 923 S.W.2d at 558–59 (concluding that the trial court did not abuse its discretion by excluding testimony by an expert who “conducted no testing to exclude other possible causes . . . even though he admitted in his deposition that many of the symptoms could be caused by” other specific conditions). We conclude that Daller’s testimony adequately excluded, with reasonable medical certainty, the other plausible causes raised by the evidence. Hunt testified that, in his opinion, Crump died from a combination of kidney failure, cirrhosis of the liver, and a fungal infection in the lungs exacerbated by preexisting diabetes and a history of immunosuppressant drug usage. There is no dispute that these conditions, except the fungal infection, all preceded Crump’s May 2000 work-related injury. All of these were other plausible causes of Crump’s death. But there was evidence that despite his long-term health problems dating from his kidney transplant twenty-five years earlier, 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. Even Hunt acknowledged that Crump’s infection was a “co-morbid condition” that made his other health conditions “more difficult to deal with.” Hunt disputed any connection between Crump’s injury and the infection, and he believed that the injury contributed nothing toward Crump’s death. He concluded that Crump would have died on January 23, 2001, regardless of the work-related injury of May 2000. But objective evidence of Crump’s good health before his injury, his contraction of an infection at the site shortly afterward, and the deleterious effect of the infection on his health reasonably ruled out the possibility that he died solely from the other conditions he suffered. Based on Daller’s experience and training as a transplant specialist and surgeon, his dealings with infection-susceptible immunosuppressed patients, and his direct dealings with Crump—which included taking cultures directly from the wound site for diagnostic purposes—he concluded that Crump’s wound became infected, that the infection weakened his organs, and that the natural progression of these events caused his death. See Crye , 907 S.W.2d at 500 (“Reasonable [medical] probability is determined by the substance and context of the opinion, and does not turn on semantics or on the use of a particular term or phrase.”). In other words, Daller’s medical causation opinion provided a cause that excluded, with reasonable medical certainty, Hunt’s suggested causes of death. The evidence was not conclusive, but it was not required to be. It was sufficiently reliable to be considered by the jury. Once Daller effectively responded to Hunt’s other plausible causes of death with reliable testimony, the question was no longer one of legal sufficiency, but rather one of competing evidence to be weighed by the jury. See Ford Motor Co. v. Ledesma , 242 S.W.3d 32, 40–41 (Tex. 2007) . In addition to applying the Robinson factors, Gammill also informs our reliability inquiry. There we concluded that the Robinson factors could not be applied to the plaintiffs’ experts, “even though mechanical engineering, the expertise claimed by the witnesses, is scientific in nature.” Gammill , 972 S.W.2d at 727 . In that situation, we asked further whether there was “simply too great an analytical gap between the data and the opinion proffered.” Id. “The ‘analytical gap’ between the data . . . and [the expert]’s opinion was not shown to be due to his techniques in assessing the vehicle restraint system. . . . Rather, the ‘gap’ in [the expert]’s analysis was his failure to show how his observations, assuming they were valid, supported his conclusions that [the passenger] was wearing her seat belt or that it was defective.” Id. The analysis set out in Gammill lends support to the reliability of Daller’s expert opinion testimony in this case. Daller is board-certified in general surgery and critical care, specializes in multiple-organ transplantation, and has worked as a clinician in teaching hospitals across the country—including the University of Texas Medical Branch at Galveston, where he treated Crump. His educational and clinical qualifications to treat post-transplantation, immunosuppressed patients, such as Crump, are not in dispute. As explained above in addressing the Robinson factors, an analytical gap between the data and opinion is not shown here because of Daller’s “techniques in assessing” Crump. See id. Rather, there must be “failure to show how his observations, assuming they were valid, supported his conclusions.” Id. He directly treated or oversaw Crump’s treatment on repeated occasions after Crump’s work-related knee injury. Daller observed that Crump’s wound was located in the same spot as the injury and that the wound site became symptomatic as being infected in a predictable time and manner after the injury for an immunosuppressed patient such as Crump. 3 He observed that, in his words, the wound infection tilted Crump’s “seesaw” away from an immunosuppressed patient’s “relative balance” between immunosuppression and infection toward systemic infection. 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. Daller observed that Crump—despite being a kidney transplant recipient with diabetes and undiagnosed hepatitis C—had no medical history of organ problems from the period after the transplant in 1975 until after the work-related injury in 2000. Daller observed the problems with Crump’s organ function and concluded that “the worsening of those organs’ functions was caused by the infection.” From these observations, Daller concluded: Q. Doctor, do you have an opinion regarding the cause of Mr. Crump’s death?
Q. And what is that opinion, sir? A. My opinion is that his death resulted from a natural sequence of events that began at the time of his knee injury. Q. Doctor, would you please elaborate as to what was the cause of the death as it related to the injury? A. Mr. Crump had had [sic] a renal transplant approximately 25 years prior, I believe. He also had what is known as compensated cirrhosis from hepatitis C. At the time that he experienced the injury, that injury caused a progression of his hepatic insufficiency, and because of his inability to fight off infections and also because of his overall medical condition, it caused a series of events that led to his death. Q. Dr. Daller , is it your opinion that the infection which Mr. Crump developed was a producing cause of his death? A. It was the trigger cause of a sequence of events that then occurred. Thus, we cannot conclude that there was “too great an analytical gap” between the observed data and the proffered opinion. See Gammill , 972 S.W.2d at 727 . At this point, any “gaps” that remain between the data and the conclusion drawn from it go to the weight of Daller’s testimony—not its reliability. See Ledesma , 242 S.W.3d at 40–41 . We conclude that Daller’s testimony was based on a sufficiently reliable foundation under the standards set out in Robinson and Gammill . Because Daller’s expert medical causation testimony is based on a reliable foundation, it was admissible at trial as evidence to prove that the May 2000 injury was a producing cause of Crump’s death. See Tex. R. Evid . 702. Consequently, on legal sufficiency review, we conclude that reasonable jurors could have believed his testimony. See City of Keller v. Wilson , 168 S.W.3d 802, 827 (Tex. 2005). Because Daller’s expert testimony was sufficient evidence to support the jury’s verdict on causation, we cannot disturb the jury’s finding against Transcontinental on the issue of producing cause. Accordingly, Transcontinental’s legal sufficiency challenge is denied.