Increased risk of chronic obstructive pulmonary disease in patients with schizophrenia: a population-based study

We investigated the prevalence and incidence of chronic obstructive pulmonary disease (COPD) among patients with schizophrenia in Taiwan.

From the database provided by the National Health Research Institute, we obtained a random sample of 766,427 subjects aged ≥18 years in 2005. Subjects with a primary or secondary diagnosis of COPD during 2005 were identified. We compared the prevalence of COPD in schizophrenic patients with that in the general population. We also detected new cases of COPD from 2006 to 2008.

The prevalence of COPD in patients with schizophrenia was higher than that in the general population (3.83% vs. 2.88%, odds ratio [OR] 1.66; 95% confidence interval [CI]),1.42-1.94) in 2005. Compared with the general population, patients with schizophrenia had a higher prevalence of COPD in individuals <50 years old and ≥70 years old; among both sexes, and among insurance amount of a fixed premium and an amount less than US$640. Patients with schizophrenia had a higher annual incidence of COPD than that in the general population (2.21% vs. 1.43%, risk ratio 1.83; 95% CI, 1.62-2.07). The higher incidence of COPD in patients with schizophrenia was associated with increased age and male sex.

Patients with schizophrenia had a higher prevalence and incidence of COPD than individuals in the general population in Taiwan. Younger adults and men with schizophrenia had a much higher prevalence of COPD compared with those groups in the general population, a result deserving further study.