Schizophrenia, but not depression or bipolar affective disorder, adds additional risk of aspiration pneumonia among stroke survivors: A national cohort study in Taiwan.

ABSTRACT

OBJECTIVE: Few studies have assessed the sex-specific and age-specific risk of aspiration pneumonia (AP) in patients with stroke and evaluated whether mental disorders may increase this risk. In this population-based cohort study, we investigated the sex-specific and age-specific risk of AP in association with stroke and the joint effects of stroke and mental disorders on the risk of AP. METHODS: We included 23,288 patients with incident stroke admitted between 2005 and 2017 and 68,675 matched nonstroke controls. Information on mental disorders was obtained from medical claims data within the 3 years before the stroke incidence. Cox proportional hazards models considering death as a competing risk event were constructed to estimate the hazard ratio of AP incidence by the end of 2018 associated with stroke and selected mental disorders. RESULTS: After ≤14 years of follow-up, AP incidence was higher in the patients with stroke than in the controls (11.30/1000 vs. 1.51/1000 person-years), representing a covariate-adjusted subdistribution hazard ratio (sHR) of 3.64, with no significant sex difference. The sHR significantly decreased with increasing age in both sexes. Stratified analyses indicated schizophrenia but not depression or bipolar affective disorder increased the risk of AP in the patients with stroke. CONCLUSION: Compared with their corresponding counterparts, the patients with schizophrenia only, stroke only, and both stroke and schizophrenia had a significantly higher sHR of 4.01, 5.16, and 8.01, respectively. The risk of AP was higher in younger stroke patients than those older than 60 years. Moreover, schizophrenia was found to increase the risk of AP in patients with stroke.