Risk of cerebrovascular events in elderly users of antipsychotics.

It has been shown that elderly patients with dementia treated with atypical and conventional antipsychotics have a twofold increased risk of cerebrovascular adverse events (CVAEs). To investigate the temporal relationship between exposure to antipsychotics and the risk of CVAE, a case-control analysis nested within a cohort of 26,157 community-dwelling patients (mean age 76 +/- 9.7) with at least one antipsychotic prescription was conducted. Data were used from Dutch community pharmacies and hospital discharge records. Five hundred and eighteen cases of hospital admission for CVAE were identified. For each case, four randomly selected controls matched by sex and age were sampled from the cohort. To evaluate the temporal relationship between antipsychotic use and the occurrence of CVAE, two measures were used: the first being a current, recent or past user, and the second for the current users, the duration of use up to the index date. In addition, the cumulative exposure was assessed. Current and recent exposure to antipsychotics were associated with an increased risk of CVAE compared with non-users (odds ratio [OR] 1.7, CI 1.4-2.2). A strong temporal relationship was found; the OR for a history of use less than a week is 9.9 (5.7-17.2). The risk decreases in time and is comparable to non-users after 3 months of use (OR 1.0, CI 0.7-1.3). Cumulative exposure was not associated with an increase in risk. The risk of CVAE in elderly patients associated with antipsychotics is elevated especially during the first weeks of treatment. This risk decreases over time and is back on base level after 3 months of treatment. Chronic use is not associated with CVAE.