Consistency of Physician Judgments of Capacity to Consent in Mild Alzheimer's Disease

Abstract

Competency judgements of physicians showed high agreement for controls but low agreement for AD patients. Physicians as a group achieved 98% judgment agreement for the controls but only 56% judgment agreement for the mild AD patients. The physician group kappa for controls was 1.00 (P < .0001) and differed significantly (P < .0001) from the physician group kappa of .14 (P = .44) for AD patients, indicative of a real difference in the ability of the study physicians to judge consistently competency across the two groups. Similarly, logistic regression analysis showed significant variability in physician judgements for the AD group (chi 2 = 63.8, P < .0001) but not for the control group (chi 2 = 4.1, P = 1.00). Within the Ad group, pairwise analyses revealed significant judgment disagreement (P < .01) for seven of the 10 physician pairs.