Increased rates of respiratory disease in schizophrenia: A systematic review and meta-analysis including 619,214 individuals with schizophrenia and 52,159,551 controls

Despite respiratory disease being a major cause of excess mortality in people with schizophrenia, the prevalence of respiratory conditions in this population is poorly defined. A systematic review and meta-analysis were conducted to establish the prevalence and association of respiratory diseases in people with schizophrenia. Major electronic databases were searched from inception to 27 April 2020 for articles reporting respiratory disease (asthma, chronic obstructive pulmonary disease [COPD], pneumonia, and tuberculosis) in people with schizophrenia and, where possible, a control group. A random-effects meta-analysis was conducted. The study was registered with PROSPERO (CRD42018115137). Of 1569 citations, 21 studies consisting of 619,214 individuals with schizophrenia and 52,159,551 controls were included in the meta-analysis. Compared to the general population, people with schizophrenia had significantly higher rates of COPD (odds ratio [OR]: 1.82, 95% CI: 1.28–2.57), asthma (OR: 1.70, 95% CI: 1.02–2.83), and pneumonia (OR: 2.62, 95% CI: 1.10–6.23). In people with schizophrenia, the prevalence of COPD was 7.7% (95% CI: 4.0–14.4), asthma 7.5% (95% CI: 4.9–11.3), pneumonia 10.3% (95% CI 5.4–18.6), and tuberculosis 0.3% (95% CI 0.1 –0.8). After adjusting for publication bias, the prevalence of COPD increased to 19.9% (95% CI: 9.6–36.7). All respiratory diseases examined were significantly more prevalent in people with schizophrenia compared with the general population. Future studies should focus on improving the prevention and management of respiratory disease in this group to reduce associated excess mortality.