Sleep apnea and risk of pneumonia: a nationwide population-based study.

BACKGROUND Evidence evaluating the risk of pneumonia in patients with obstructive sleep apnea is limited and mostly focuses on patients who receive continuous positive airway pressure (CPAP) therapy or on pediatric patients. We aimed to explore the risk of incident pneumonia among adults with sleep apnea, either with or without the need of CPAP therapy. METHODS From Jan. 1, 2000, we identified adult patients with sleep apnea from the Taiwan National Health Insurance Research Database. A control cohort without sleep apnea, matched for age, sex and comorbidities, was selected for comparison. The 2 cohorts were followed until Dec. 31, 2010, and observed for occurrence of pneumonia. RESULTS Of the 34,100 patients (6816 study patients and 27,284 matched controls), 2757 (8.09%) had pneumonia during a mean follow-up period of 4.50 years, including 638 (9.36%) study patients and 2119 (7.77%) controls. Kaplan-Meier analysis showed a higher incidence of pneumonia among patients with sleep apnea (log rank test, p < 0.001). After multivariate adjustment, patients with sleep apnea experienced a 1.20-fold (95% confidence interval 1.10-1.31) increase in incident pneumonia. The risk was even higher among patients who received CPAP therapy. INTERPRETATION Sleep apnea appeared to confer a higher risk for future pneumonia, possibly in a severity-dependent manner.