Medical Malpractice Causation Revisited

By Alex Stein

Evidence law requires the plaintiff to prove every element of her suit by a preponderance of the evidence.  Under this requirement, an aggrieved patient will not succeed in her suit against the doctor unless she adduces persuasive evidence of causation. This evidence must demonstrate that it is more probable than not that the doctor’s malpractice caused the patient’s damage. Satisfying this requirement is difficult because doctors can virtually always blame the patient’s damage on her preexisting medical condition. This factor makes causation in a medical malpractice case an extremely complex issue. In the absence of special legal rules, this issue could present an insurmountable evidentiary obstacle for many wronged patients. Courts responded to this problem by relaxing the causation requirements for medical malpractice suits. They have developed what I call the “relaxed causation” doctrine: see Toward a Theory of Medical Malpractice, 97 Iowa L. Rev. 1201, 1216-26 (2012). The doctrine’s idea is to close the exit from liability for negligent doctors: these doctors should not go scot free because of the patient’s preexisting condition that complicates the causation issue.

This doctrine was at play in a recent case Klein v. Aronchick, — A.3d —-, 2014 WL 46648 (Pa. Super. 2014).

This case involved a patient whose doctor treated her chronic constipation with Visicol. The doctor was the inventor and patent-holder of Visicol – a drug that was tested and approved as a preparation to cleanse the colon for a colonoscopy. The doctor’s prescription of Visicol for the patient’s treatment of chronic constipation thus was an off-label use. The patient developed a kidney disease, which she attributed to Visicol. Her expert testified that Visicol was contraindicated and that its prolonged use by the patient caused the disease. The doctor’s experts attributed he disease to the patient’s medical history that included bulimia, hypertension, and an extensive use of non-steroidal anti-inflammatory drugs (aspirin, ibuprofen, etc.). The jury found the doctor negligent but decided that the patient failed to prove causation and dismissed the suit.

Pennsylvania’s governing precedent on relaxed causation, Hamil v. Bashline, 392 A.2d 1280 (Pa. 1978), holds that jurors can (but do not have to) deem causation established whenever they find that the negligent doctor substantially increased the patient’s risk of illness or injury. Another decision, Mitzelfelt v. Kamrin, 584 A.2d 888 (Pa. 1990), indicated that the “increased risk” theory of recovery will only be available to an aggrieved patient who has no sustainable claim of direct causation because of her preexisting condition. Direct causation and “increased risk” thus came to be understood as mutually exclusive theories of recovery. Based on that understanding, the trial judge declined to give the jurors the “increased risk” instruction.

The appellate court, however, has decided that the trial judge was wrong. The court held that an aggrieved patient with a preexisting condition is entitled to both instructions. Put differently, the patient can try to prove causation directly, and if she fails, she could still prove it under the “increased risk” theory.

This is an important and correct decision. For various policy reasons, articulated in the above-cited article, courts should narrow doctors’ entry into “negligence” but a negligent doctor’s exit from liability should be narrow as well. Courts across the United States follow this policy with remarkable and commendable unanimity.

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About Alex Stein

Alex Stein is a Professor of Law at Brooklyn Law School. Before joining Brooklyn, Alex was a Professor of Law at Cardozo Law School (2004-2016) and served for more than a decade at the Hebrew University of Jerusalem Faculty of Law (1991-2004). He also held visiting professorial appointments at Alabama, Columbia, Miami, and Yale Law Schools. In Fall 2016, he visited Harvard Law School, where he taught Torts and a seminar on Medical Malpractice. Alex's specialty areas include Torts, Medical Malpractice, Evidence, as well as general legal theory and economic analysis of law. He authors three books, An Analytical Approach to Evidence (with Ronald J. Allen et al.) (6th ed. 2016); Foundations of Evidence Law (2005) and Tort Liability under Uncertainty (2001, with Ariel Porat), and over sixty articles of which many have appeared in leading journals. Alex was one of the founding editors of Theoretical Inquiries in Law and is on the editorial board of the International Journal of Evidence & Proof. In 2013, he launched an e-journal STEIN on Medical Malpractice,, that covers all significant developments in medical malpractice laws across the United States. He graduated from the Hebrew University of Jerusalem and earned a Ph.D. from the University of London.

2 thoughts on “Medical Malpractice Causation Revisited

  1. This is a thoughtful and understandable explanation of the important reasons why doctors who are negligent should be liable for creating an increased risk of harm to their patients.

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