Physicians' and spouses' predictions of elderly patients' resuscitation preferences.

"Substituted judgment," in which surrogate decisionmakers approximate patients' wishes, has been recommended for decision making for mentally incapacitated patients. To test understanding of patients' preferences by potential surrogate decisionmakers, we studied primary care physicians' (n = 105) and spouses' (n = 90) predictions of elderly outpatients' (n = 258) preferences for cardiopulmonary resuscitation (CPR) and CPR plus ventilator (CPR + V), assuming three baseline health states: current health, stroke, and chronic lung disease. Although more than three-quarters of physicians and spouses surveyed believed their predictions of patients' preferences were accurate, the accuracy of physicians' and spouses' predictions did not exceed that expected due to chance alone in 5 of 6, and 3 of 6 decisions, respectively. Physicians significantly underestimated patients' preferences for resuscitation in the stroke and chronic lung disease scenarios (p less than .01), and significantly overestimated them in the current health/CPR decision (p less than .05). Spouses overestimated patients' preferences for resuscitation in all decisions, significantly so in the three CPR + V decisions (p less than .05). These results suggest physicians and spouses often do not understand elderly outpatients' resuscitation preferences. Under these circumstances they are unlikely to provide accurate substituted judgments.