Modal preferences predict elderly patients' life-sustaining treatment choices as well as patients' chosen surrogates do

The purpose of this study was to compare the accuracy of an actuarial metho d of predicting patients' preferences for life-sustaining treatment with th e accuracy of surrogate decision makers. 401 outpatients 65 years old or ol der (mean = 73 years) and their self-designated surrogate decision makers r ecorded preferences for four life-sustaining medical treatments in nine hyp othetical illness scenarios. The surrogates did not predict the patients' p references more accurately than did an actuarial model using modal preferen ces. Surrogates' accuracy was not influenced by the use of an advance direc tive (AD) or discussion of life-sustaining treatment choices. In clinical p ractice, an actuarial model could assist surrogate decision makers when a p atient has no AD, an AD is unavailable, a patient's AD is vague or describe s treatment choices for only extreme or unlikely disease states, no proxy d ecision maker has been designated, or a patient was never competent.