Objective: To evaluate if anger expression affects sleep quality in patients with coronary heart disease (CHD). Research has indicated that poor sleep quality independently predicts adverse outcomes in patients with CHD. Risk factors for poor sleep quality include older age, socioeconomic factors, medical comorbidities, lack of exercise, and depression.
Methods: We sought to examine the association of anger expression with sleep quality in 1020 outpatients with CHD from the Heart and Soul Study. We assessed anger-in, anger-out, and anger temperament, using the Spielberger State-Trait Anger Expression Inventory 2, and measured sleep quality, using items from the Cardiovascular Health Study and Pittsburgh Sleep Quality Index. We used multivariate analysis of variance to examine the association between anger expression and sleep quality, adjusting for potential confounding variables.
Results: Each standard deviation (SD) increase in anger-in was associated with an 80% greater odds of poor sleep quality (odds ratio (OR) = 1.8, 95% Confidence Interval (CI) = 1.6-2.1; p < .0001). This association remained strong after adjusting for demographics, comorbidities, lifestyle factors, medications, cardiac function, depressive symptoms, anger-out, and anger temperament (adjusted OR = 1.4, 95% CI = 1.5-1.7; p = .001). In the same model, each SD increase in anger-out was associated with a 21% decreased odds of poor sleep quality (OR = 0.79, 95% CI = 0.64-0.98; p = .03). Anger temperament was not independently associated with sleep quality.
Conclusions: Anger suppression is associated with poor sleep quality in patients with CHD. Whether modifying anger expression can improve sleep quality or reduce cardiovascular morbidity and mortality deserves further study.