DESIGN: Cross-sectional interview-based and questionnaire-based survey.

SETTING: Two university general internal medicine practices, two Department of Veterans Affairs general internal medicine practices, and one university-based geriatrics practice, in two different cities.

PATIENTS: Fifty-six patients of primary care internists.

INTERVENTION: Physicians discussed “advance directives” (ADs) with one randomly selected patient during an outpatient visit.

MEASUREMENTS AND MAIN RESULTS: After the discussions, physicians identified the patient’s proxy and predicted the patient’s preferences for treatment in 20 scenarios. Patients provided treatment preferences in the 20 scenarios, the name of their preferred surrogate decision maker, and their understanding of cardiopulmonary resuscitation and mechanical ventilation. Of the 39 patients who discussed resuscitation, 43% were able to identify two important characteristics; 26% identified none; 66% did not know that most patients need mechanical ventilation after undergoing resuscitation. None of the 43 patients who had a discussion about mechanical ventilation had a good understanding of it; 67% did not know that patients generally cannot talk while on ventilators; 46% expressed serious misconceptions about ventilators. There was poor agreement between physicians and their patients regarding treatment preferences in 18 of 20 scenarios (κ −0.04 to 0.31). Physicians correctly identified the proxy 89% of the time (κ 0.78).

CONCLUSIONS: Patients leave routine AD discussions with serious misconceptions about life-sustaining treatments. Physicians are unable to predict treatment preferences but do learn about patients’ preferences for surrogate decision makers.