Poor sleep increases the prospective risk for recurrent events in middle-aged women with coronary disease. The Stockholm Female Coronary Risk Study

Objective: We investigated the prognostic impact of sleep complaints in women with CHD and also examined whether the association between sleep problems and cardiac events could be explained by depression.

Methods: All women patients, aged 65 or under who were admitted with an acute coronary syndrome between 1991 and 1994 in Stockholm, were followed for 5 years for recurrent coronary events. Sleep complaints and depression were measured at baseline using standardized questionnaires. Quality of sleep, restorative function of sleep, and snoring were assessed by the Karolinska Sleep Questionnaire (KSQ), and depressive symptoms by a questionnaire developed by Pearlin.

Results: Poor sleep quality was associated with recurrent cardiac events. After multivariate adjustment for age, and standard risk factors, the hazard ratio (HR) for women with poor as compared with good sleep quality was 2.5 (95% CI: 1.2-5.2). Controlling for depression did not change this result substantial. Not waking up well-rested yielded a similarly increased risk (HR = 2.4; 95% CI: 1.2-4.6). Women with both poor sleep quality and depression had a worse prognosis than women free from these complaints (HR = 2.6; 95% CI: 1.0-6.4). Heavy snoring was not related to prognosis.

Conclusions: Our results indicate that poor sleep and sleep without a restorative function are associated with poor prognosis in female coronary patients. This association is not explained by depressive symptoms or by standard coronary risk factors.