Sleep problems associated with long-term mortality in acute coronary syndrome: Effects of depression comorbidity and treatment

Objectives: The effects of sleep disturbance and its treatment on the prognosis of patients with acute coronary syndrome (ACS) are not well understood. This study investigated the impact of sleep disturbance on long-term all-cause mortality, according to depression comorbidity and treatment, in patients with ACS. Methods: A cross-sectional baseline study and a nested 24-week double-blind escitalopram-placebo controlled trial were carried out from May 2007 to March 2013; 5-12-year follow-up for all-cause mortality was conducted. A total of 1152 patients with ACS were stratified by baseline depression comorbidity and treatment allocation into four groups: no depression (N = 706), depression on escitalopram (N = 149), depression on placebo (N = 151), and depression on medical care as usual (CAU; N = 146). Sleep disturbance was evaluated by the Leeds Sleep Evaluation Questionnaire. During the 5-12-year follow-up, Kaplan-Meyer event rates for all-cause mortality were calculated; hazard ratios (HRs) using Cox regression models were estimated after adjustment for a range of covariates. Results: Worse sleep states at baseline increased long-term all-cause mortality in all patients (HRs 1.08-1.59). The associations between worse sleep states and long-term all-cause mortality were significant in patients without depression and in patients with depression who received CAU, but not in patients with depression who participated in the 24-week trial. Conclusions: Routine evaluations of sleep disturbance in ACS and further treatment allocation may contribute to reducing long-term mortality associated with the disease.