Adverse events in elderly users of antipsychotic pharmacotherapy in the province of Manitoba: a retrospective cohort study.

Background: Antipsychotic medications have been widely used in elderly patients for treatment of a variety of diagnoses. The aim of our study was to compare the incidence of cerebrovascular and cardiac events as well as mortality in elderly persons treated with second-generation antipsychotics (SGAs) with that of elderly persons treated with conventional first-generation agents (FGAs) in the province of Manitoba.

Methods: A population-based retrospective cohort study of all residents of Manitoba aged 65 and older, who were dispensed antipsychotic medications for the first time during the period from April 1, 2000, to March 31, 2007, was conducted using Manitoba Health administrative databases. Cox proportional hazards models were used to compare risks of adverse events in FGA and SGA users.

Results: After controlling for potential confounders (demographics, comorbidity, and medication use), SGA use was not associated with a significantly greater risk of cerebrovascular events, cardiac arrhythmia, and congestive heart failure compared to FGA use (adjusted hazard ratios [HR], respectively: 1.136; 95% CI, 0.961-1.344; 0.865; 95% CI, 0.336-2.232; 1.127, 95% CI, 0.902-1.409). Second-generation antipsychotics users were found to be at a lower risk of mortality (adjusted HR, 0.683; 95% CI, 0.577-0.809), but at a higher risk of myocardial infarction (adjusted HR, 1.614; 95% CI, 1.024-2.543) compared to FGA users.

Conclusions: Among elderly users of antipsychotic medications, the risk of cerebrovascular events, cardiac arrhythmia, and congestive heart failure was similar in FGA and SGA users. Whereas SGA users were at a higher risk of nonfatal myocardial infarction, the use of FGAs was associated with an increased risk of death. Antipsychotic pharmacotherapy in older persons needs to be chosen with careful consideration of all risks and benefits.