Defensive medicine, also called defensive medical decision making, refers to the practice of recommending a diagnostic test or treatment that is not necessarily the best option for the patient, but an option that mainly serves the function to protect the physician against the patient as potential plaintiff. Defensive medicine is a reaction to the rising costs of malpractice insurance premiums and patients’ biases on suing for missed or delayed diagnosis or treatment but not for being overdiagnosed. U.S. physicians are at highest risk of being sued, and overtreatment is common. The number of lawsuits against physicians in the USA has increased within the last decades and has had a substantial impact on the behavior of physicians and medical practice. Physicians order tests and avoid treating high-risk patients in order to reduce their exposure to lawsuits, or are forced to discontinue practicing because of overly high insurance premiums. This behavior has become known as defensive medicine, "a deviation from sound medical practice that is indicated primarily by a threat of liability."
Forms of defensive medicine
Defensive medicine takes two main forms: assurance behavior and avoidance behavior. Assurance behavior involves the charging of additional, unnecessary services in order to a) reduce adverse outcomes, b) deter patients from filing medical malpractice claims, or c) provide documented evidence that the practitioner is practicing according to the standard of care, so that if, in the future, legal action is initiated, liability can be pre-empted. Avoidance behavior occurs when providers refuse to participate in high risk procedures or circumstances.
In 2004, the case of Dr. Daniel Merenstein triggered an intensive debate in scientific journals and media on defensive medicine (e.g.,) Following the guidelines of several well-respected national organizations, Merenstein had explained the pros and cons of prostate-specific antigen (PSA) testing to a patient, rather than simply ordering the test. He then documented the shared decision not to order the test. Later, the patient was diagnosed with incurable advanced prostate cancer, and Merenstein and his residency were sued for not ordering the test. Although Merenstein was acquitted, his residency was found liable for $1 million. Ever since this ordeal, he regards his patients as potential plaintiffs: ‘I order more tests now, am more nervous around patients: I am no longer the doctor I should be’. In a study with 824 US surgeons, obstetricians, and other specialists at high risk of litigation, 93% reported practicing defensive medicine, such as ordering unnecessary CTs, biopsies, and MRIs, and prescribing more antibiotics than medically indicated. In Switzerland, where litigation is less common, 41% of general practitioners and 43% of internists, reported that they sometimes or often recommend PSA tests for legal reasons. The practice of defensive medicine also expresses itself in discrepancies between what treatments doctors recommend to patients, and what they recommend to their own families. In Switzerland, for instance, the rate of hysterectomy in the general population is 16%, whereas among doctors’ wives and female doctors it is only 10%.
Financial consequences of defensive medical decision making
Defensive medical decision making has spread to many areas of clinical medicine and is seen as a major factor in the increase in health care costs, estimated at tens of billions of dollars annually in the USA. An analysis of a random sample of 1452 closed malpractice claims from five U.S. liability insurers showed that the average time between injury and resolution was 5 years. Indemnity costs were $376 million, and defense administration cost $73 million, resulting in total costs of $449 million. The system’s overhead costs were exorbitant: 35% of the indemnity payments went to the plaintiffs’ attorneys, and together with defense costs, the total costs of litigation amounted to 54% of the compensation paid to plaintiffs.
Consequences for patient care
Theoretical arguments based on utilitarianism conclude that defensive medicine is, on average, harmful to patients. Malpractice suits are often seen as a mechanism to improve the quality of care, but with custom-based liability, they actually impede the translation of evidence into practice, harming patients and decreasing the quality of care. Tort law in many countries and jurisdictions not only discourages but actively penalizes physicians who practice evidence-based medicine.
Defensive decision making in other domains
Defensive decision making do not only occur in health care but also in business and politics. For instance, managers of large international companies report making defensive decisions in one third to half of all cases, on average.  That means, these managers pursue options that are second best for their company but protect themselves in case something goes wrong.
- Studdert, D. M., Mello, M. M., Sage, W. M., DesRoches, C. M., Peugh, J., Zapert, K. & Brennan, T. A. (2005) Defensive medicine among high-risk specialist physicians in a volatile malpractice environment. JAMA, 293 (21), 2609–2617.
- Hurwitz, B. (2004) How does evidence based guidance influence determinations of medical negligence? British Medical Journal, 329 (7473), 1024–1028.
- Atkins, D., Siegel, J. & Slutsky, J. (2005) Making policy when the evidence is in dispute. Health Affairs, 24 (1), 102–113.
- Merenstein, D. (2004) Apiece of my mind. Winners and losers. JAMA, 291 (1), 15–16.
- Lapp, T. (2005) Clinical guidelines in court: it’s a tug of war. American Academy of Family Physicians Report, 2005. Available at: http:// www.aafp.org/x33422.xml (last accessed 12 February 2008).
- Steurer, J., Held, U., Schmidt, M., Gigerenzer, G., Tag, B., & Bachmann L. M. (2009). Legal concerns trigger PSA testing. Journal of Evaluation in Clinical Practice, 15, 390-392.
- Domenighetti, G., Casabianca, A., Gutzwiller, F., & Martinoli, S. (1993). Revisiting the most informed consumer of surgical services: The physician-patient. International Journal of Technology Assessment in Health Care, 9, 505–513.
- Anderson, R. E. (1999) Billions for defense: the pervasive nature of defensive medicine. Archives of Internal Medicine, 159 (20), 2399–2402.
- Studdert, D. M., Mello, M.M., Gawande, A. A., Gandhi, T.K., Kachalia, A., Yoon, C., Puopolo, A. L. & Brennan, T.A. (2006). Claims, errors, and compensation payments in medical malpractice litigation. New England Journal of Medicine, 354, 2024-33.
- DeKay ML, Asch DA. Is the defensive use of diagnostic tests good for patients, or bad? Med Decis Making. 1998;18:19-28.
- Monahan, J. (2007). Statistical literacy. A prerequisite for evidence-based medicine. Psychological Science in the Public Interest, 8, i-ii.
- Gigerenzer, G. (2014) Risk savvy: How to make good decisions. New York: Viking.