Impaired cognitive function and compliance with antihypertensive drugs in elderly: the Rotterdam Study

To our knowledge, there are no epidemiologic studies on the association between cognitive impairment and noncompliance with antihypertensive therapy. We studied compliance with antihypertensive treatment in elderly patients with cognitive impairment.

The Rotterdam Study is a prospective community-based cohort study of 7983 residents > or = 55 years old. We studied 1979 participants in the study who had 2 consecutive Mini Mental State Examination (MMSE) assessments in the period from 1991 to 1996, who did not have dementia at baseline, and who had received 3 or more consecutive antihypertensive prescriptions for at least 6 months. We compared persons with MMSE scores < or = 25 on both assessments to persons with MMSE scores > 25 on both occasions. Compliance was estimated by dividing the number of days the subjects took antihypertensive drugs by the follow-up period in days, and it was expressed as a ratio between 0 and 1. We defined patients as compliant if they had a compliance ratio > or = 0.80 and as noncompliant if they had a compliance ratio < or = 0.50 during the study period.

We followed-up on 1573 patients (mean age, 68 years) during an average period of 1609 days. The risk of noncompliance in cognitively impaired elderly subjects was 2.0 (95% confidence interval, 1.4 to 2.8) after adjustment for age, sex, education, income, living situation, and smoking. Stratification by living situation showed that the risk increase predominantly occurred in those who lived alone (odds ratio, 2.9; 95% confidence interval, 1.2 to 7.5).

Cognitive function is an independent predictor of compliance with antihypertensive drugs in elderly patients who are living alone.