Mortality of patients with obstructive sleep apnea in Korea

Obstructive sleep apnea (OSA) is associated with diverse health risks, including death. However, the role of OSA as a risk factor for death has never been studied in Asians. This study is aimed at evaluating the influence of OSA on the mortality in Korean sleep clinic population.

A total of 2,240 patients who underwent in-laboratory full-night polysomnography due to snoring or sleep apnea were included. The patients were categorized based on apnea-hypopnea index (AHI)/hour. Death records were provided from the Statistics Korea. A Cox-proportional hazard regression model and Kaplan-Meier survival curve were used for analysis and demonstration of the all-cause mortality and cardiovascular mortality.

The all-cause mortality risk adjusted for age, sex, body mass index, diabetes, hypertension, cardiovascular diseases, and previous history of stroke was significantly associated with the increased severity of OSA. The adjusted hazard ratio (HR) for all-cause mortality in the severe OSA group (AHI ≥ 30) vs. reference group (5 < AHI) was 2.47 (95% confidence interval [CI], 1.09-5.57) and the adjusted HR for cardiovascular mortality was 4.66 (CI 1.03-21.08). After adjusting for whether the patients were treated or untreated, the HR for all-cause and cardiovascular mortality in the severe OSA group vs. reference group were 2.14 (p = 0.079) and 4.19 (p = 0.076), respectively.

The present study showed that the increased mortality was also associated with the increased severity of OSA in Koreans as shown in the studies performed in the Western countries.