NONMEDICAL INFLUENCES ON MEDICAL DECISION-MAKING

Background. The influence of non-medical factors on physicians' decisi on-making has been documented in many observational studies, but rarel y in an experimental setting capable of demonstrating cause and effect . We conducted a controlled factorial experiment to assess the influen ce of non-medical factors on the diagnostic and treatment decisions ma de by practitioners of internal medicine in two common medical situati ons. Methods. One hundred and ninety-two white male internists individ ually viewed professionally produced video scenarios in which the acto r-patient, presenting with either chest pain or dyspnea, possessed var ious balanced combinations of sex, race, age, socioeconomic status, an d health insurance coverage. Physician subjects were randomly drawn fr om lists of internists in private practice, hospital-based practice, a nd HMO's, at two levels of experience. Results. The most frequent diag noses for both chest pain and dyspnea were psychogenic origin and card iac problems. Smoking cessation was the most frequent treatment recomm endation for both conditions. Younger patients (all other factors bein g the same) were significantly more likely to receive the psychogenic diagnosis. Older patients were more likely to receive the cardiac diag nosis for chest pain, particularly if they were insured. HMO-based phy sicians were more likely to recommend a follow-up visit for chest pain . Several interactions of patient and physician factors were significa nt in addition to the main effects. Conclusions. The variability in de cision-making evidenced by physicians in this experiment was not entir ely accounted for by strictly rational Bayesian inference (the common prescriptive model for medical decision-making), in-as-much as non-med ical factors significantly affected the decisions that they made. Ther e is a need to supplement idealized medical schemata with consideratio ns of social behavior in any comprehensive theory of medical decision- making.