How does an Alzheimer's disease patient's role in medical decision making change over time?

As persons with Alzheimer's disease (AD) lose their ability to make decisions, someone else has to make decisions for them. We performed a prospective cohort study of 77 AD patient-caregiver dyads to examine when this transition occurs. When dementia severity surpassed a threshold marked by a Mini-Mental State Examination (MMSE) score less than 20, the level of caregiver-reported patient involvement in the medical decision-making process declined (Moderate [MMSE = 19-12]: Odds Ratio [OR] = 2.35, 95% confidence interval [95% CI] = 1.01-5.49; P =.048; Severe [MMSE < 12]: OR = 29.38, 95% CI = 5.98-144.25, P <.001). Furthermore, older patients (OR = 1.06, 95% CI = 1.00-1.12, P =.049) and mounting caregiver burden (OR = 1.12, 95% CI = 1.04-1.26, P =.003) were significant independent predictors of transitions to the caregiver-dominated medical decision-making process. These results provide clinicians with prognostic information that can help caregivers understand how their role in decision making will change over the course of a patient's dementing illness.