BACKGROUND: The prevalence of depression is 4- to 5-fold higher in heart failure patients than in the general population. We examined the influence of depression on all-cause mortality in patients with heart failure.

METHODS AND RESULTS: Using Danish medical registries, this nationwide population-based cohort study included all patients with a first-time hospitalization for heart failure (1995-2014). All-cause mortality risks and 19-year mortality rate ratios were estimated based on Cox regression analysis, adjusting for age, sex, time period, comorbidity, and socioeconomic status. The analysis included 9636 patients with and 194 887 patients without a diagnosis of depression. Compared with patients without a history of depression, those with depression had higher 1-year (36% versus 33%) and 5-year (68% versus 63%) mortality risks. Overall, the adjusted mortality rate ratio was 1.03 (95% CI 1.01-1.06). Compared with no depression, the adjusted mortality rate ratios for mild, moderate, and severe depression, as defined by diagnostic codes, were 1.06 (95% CI 1.00-1.13), 1.03 (95% CI 0.99-1.08), and 1.02 (95% CI 0.96-1.09), respectively. In a subcohort of patients, the mortality rate ratios were modified by left ventricular ejection fraction, with adjusted mortality rate ratios of 1.17 (95% CI, 1.05-1.31) for ≤35%, 0.98 (95% CI 0.81-1.18) for 36% to 49%, and 0.96 (95% CI 0.74-1.25) for ≥50%. Results were consistent after adjustment for alcohol abuse and smoking.

CONCLUSIONS: A history of depression was an adverse prognostic factor for all-cause mortality in heart failure patients with left ventricular ejection fraction ≤35% but not for other heart failure patients.