Obstructive sleep apnea and risk of suicide and self-harm: a Danish Nationwide Cohort Study

Study Objectives In this nationwide study, we used the unique Danish registries to estimate the risk of suicide and deliberate self-harm in patients with obstructive sleep apnea (OSA). Methods We identified all Danish citizens receiving a diagnosis of OSA between 1995 and 2015. As a reference cohort, we randomly selected 10 citizens for each patient, matched by sex and birth year. Using the Fine and Gray competing risk regression, we estimated the cumulative incidences of suicide, and Cox proportional regression analysis was used to compare the risk of suicide and deliberate self-harm in patients with OSA with the reference cohort. Results We identified 48 168 patients with OSA. A total of 135 patients had died by suicide, compared with 999 suicides in the reference cohort. Patients with OSA had an increased risk of dying by suicide when compared with the reference cohort (hazard ratio, 1.29; 95% CI = 1.07% to 1.55%; and subhazard ratio, 1.23; 95% CI = 1.10% to 1.45%). We identified 1004 events of self-harm among patients with OSA, and 5270 events in the reference group. The overall risk of self-harm was increased in patients with OSA when compared with the reference group (hazard ratio, 1.28; 95% CI = 1.19% to 1.37%). Conclusions This is the first study to estimate the risk of suicide and deliberate self-harm in patients with OSA. We found that patients with OSA have an increased risk of both suicide and deliberate self-harm when compared with a large reference cohort, thereby highlighting the importance of a mental health screening in these patients.