Elderly patients' understanding of their drug therapy: the effect of cognitive function.

The relationship between cognitive function and knowledge about drug therapy and its risks was examined in 207 elderly patients attending a geriatric outpatient clinic. The patients' reports of their therapy were compared with those of their clinic doctor. Patient-doctor agreement on the number of drugs taken per patient fell with increasing age independently of change in cognitive function. However, knowledge about drugs was related to cognitive function. Many patients taking some of the potentially more dangerous drugs were ignorant of possible side-effects of their treatment. Doctors need to be trained more effectively in communicating with elderly patients about their treatment and its risks.