Effect of comorbidity on the risk of death associated with antipsychotic use among community-dwelling older adults.

Background: Antipsychotics are associated with adverse events and mortality among older adults with dementia. The objective of this study was to evaluate the risk of death associated with antipsychotic use among community-dwelling older adults with a range of comorbidities. Methods: This was a population-based cohort study of all 2,224 residents of Leppavirta, Finland, aged ≥65 years on 1 January 2000. Records of all reimbursed drug purchases were extracted from the Finnish National Prescription Register and diagnostic data were obtained from the Special Reimbursement Register. All-cause mortality was evaluated over a nine-year follow-up period. Time-dependent Cox proportional hazard models were used to compute unadjusted and adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) of mortality of antipsychotic use compared to non-use. Results: In total, 332 residents used antipsychotics between 2000 and 2008. The unadjusted HR for risk of death associated with antipsychotic use was 2.71 (95% CI = 2.3–3.2). After adjusting for baseline age, sex, antidepressant use, and diagnostic confounders, the HR was 2.07 (95% CI = 1.73–2.47). The adjusted HR was the highest among antipsychotic users with baseline respiratory disease (HR = 2.21, 95% CI = 1.30–3.76). Conclusions: The increased risk of death associated with antipsychotic use was similar across diagnostic categories, the highest being among those with baseline respiratory disease. However, the results should be interpreted with caution, as the overall sample size of antipsychotic users was small. As in other observational studies, residual confounding may account for the higher mortality observed among antipsychotic users. Further research is needed to confirm these findings.