Risk of Hospitalization for Hip Fracture and Pneumonia Associated with Antipsychotic Prescribing in the Elderly

Abstract

Antipsychotics are commonly used in the elderly to treat the behavioural symptoms of dementia. Randomized controlled trial data on the safety of antipsychotics are limited and little is known about the long-term effects of these medicines. Observational studies have investigated the risk of hip fracture and pneumonia associated with the use of antipsychotics, but varying results may be due to lack of control for unmeasured confounding. The aim of the study was to investigate the risk of hospitalization for hip fracture and pneumonia in elderly subjects exposed to antipsychotic medication using the self-controlled case-series design to control for unmeasured confounding. The source of data for this study was the Australian Government Department of Veterans' Affairs Health Care Claims Database. A self-controlled case-series design was used to measure the excess risk of hospitalization for hip fracture and pneumonia after antipsychotic exposure compared with no-exposure over the 4-year period from 2005 to 2008. There was a significantly increased risk of hip fracture 1 week after exposure to typical antipsychotics, and the risk remained significantly raised with >12 weeks of continuous exposure (incidence rate ratio [IRR] 2.19; 95% CI 1.62, 2.95). The risk of hip fracture was highest in the first week after initiation of atypical antipsychotics (IRR 2.17; 95% CI 1.54, 3.06). The risk then declined with longer-term treatment; however, it remained significantly raised with >12 weeks of continuous exposure (IRR 1.43; 95% CI 1.23, 1.66). The risk of hospitalization for pneumonia was raised in all post-exposure periods for both typical and atypical antipsychotics. Antipsychotic use in the elderly is associated with an increased risk of hospitalization for hip fracture and pneumonia. Given the increased risks of morbidity and mortality associated with these outcomes, practitioners should consider these additional risks when prescribing antipsychotics to treat behavioural symptoms of dementia in the elderly.