Worry and rumination predict insomnia in patients with coronary heart disease: a cross-sectional study with long-term follow-up.

STUDY OBJECTIVES Insomnia is highly prevalent and associated with anxiety and depression in coronary heart disease (CHD) patients. The development of effective psychological interventions is needed. Worry and rumination are potential risk factors for the maintenance of insomnia, anxiety and depression that may be modified by psychological treatment grounded in the Self-Regulatory Executive Function model. However, the relationships between worry, rumination, anxiety and depression and insomnia are not known. Therefore, we investigated these relationships both cross-sectionally and longitudinally among CHD patients. METHODS A cross-sectional study consecutively included 1082 patients in 2014-15, and 686 were followed up after mean of 4.7 years. Data were gathered from hospital records and self-report questionnaires comprising assessment of worry (Penn State Worry Questionnaire), rumination (Ruminative Responses Scale), anxiety and depression (Hospital Anxiety and Depression Scale) and insomnia (Bergen Insomnia Scale). RESULTS Insomnia correlated moderately with all other psychological variables (R 0.18-0.50, all p-values <0.001). After adjustments for anxiety and depression, Odds Ratios for insomnia at baseline were 1.27 (95% CI 1.08-1-50) and 1.60 (95% CI 1.31-1.94) per 10 points increase of worry and rumination, respectively. Corresponding Odds Ratios for insomnia at follow-up were 1.28 (95% CI 1.05-1.55) and 1.38 (95% CI 1.09-1.75). Depression was no longer significantly associated with insomnia after adjustments for worry and rumination, but anxiety remained significant. CONCLUSIONS Worry and rumination predicted insomnia both cross-sectionally and prospectively, even after controlling for anxiety and depression, although anxiety remained significant. Future studies may test psychological interventions targeting these factors in CHD patients with insomnia.