Antipsychotics have been associated with increased pneumonia risk, but although persons with dementia are particularly susceptible to pneumonia, only one small study assessed the risk of pneumonia in relation to antipsychotic use among persons with Alzheimer’s disease (AD).
We investigated whether incident antipsychotic use, or specific antipsychotics are related to higher risk of hospitalisation or death due to pneumonia in the MEDALZ cohort. The cohort includes all persons with AD who received a clinically verified AD diagnosis in Finland in 2005-2011 (N=60,584, n with incident pneumonia 12,225). A matched comparison cohort without AD (N=60,584, n with incident pneumonia 6,195) was used to compare the magnitude of risk. Results were adjusted for a propensity score derived from comorbidities, concomitant medications and sociodemographic characteristics. Sensitivity analyses with case-crossover design were conducted.
Antipsychotic use was associated with higher pneumonia risk (adjusted hazard ratio, 95% confidence interval (CI) 2.01, 1.90-2.13) in the AD cohort and somewhat higher risk in the non-AD cohort (3.43, 2.99-3.93). Similar results were observed with case-crossover analyses (odds ratio 2.02, 95% CI 1.75-2.34 in the AD cohort, 2.59, 1.77-3.79 in the non-AD cohort). The three most commonly used antipsychotics (quetiapine, risperidone, haloperidol) had similar associations with pneumonia risk.
Regardless of applied study design, treatment duration, or the choice of drug, antipsychotic use was associated with higher risk of pneumonia. With observational data we cannot fully rule out a shared causality between pneumonia and antipsychotic use, but the risk-benefit balance should be considered when antipsychotics are prescribed.