Mechanisms of the association between depressive symptoms and long-term mortality in heart failure

Background: The long-term prognostic influence of depression on patients hospitalized for heart failure (HF) is unknown. No previous study has examined systematically the mechanisms of the relationship between depression and mortality in HF.

Methods: Prospective study of 433 patients hospitalized for HF-related emergencies in 4 Spanish hospitals. Baseline depressive symptoms were assessed with the 10-item Geriatric Depression Scale (GDS). The association between depressive symptoms and mortality was summarized with hazard ratios (HRs) obtained from Cox regression, with sequential adjustment for possible mechanisms of the association.

Results: Of the 433 study participants, 103 (23.8%) had major depression (GDS-10 > or =5) at baseline. During a mean follow-up of 5.7 years, 305 deaths (70%) occurred. Compared with those who were not depressed, subjects with major depression showed higher mortality (age and sex-adjusted HR 1.52, 95% CI 1.15-2.01). Subsequent adjustment for comorbidity reduced the HR to 1.45 (95% CI 1.10-1.93). Additional adjustment for severity of cardiac lesion and for lifestyles, foremost physical inactivity, led to a HR of 1.27 (95% CI 0.95-1.70). After further adjustment for pharmacologic treatment of HF and particularly for disability in instrumental activities of daily living, the HR dropped almost to the null value (HR 1.10, 95% CI 0.82-1.49).

Conclusions: Depressive symptoms in patients hospitalized for HF are associated with higher long-term mortality; this association is largely explained by the frequent comorbidity, physical inactivity, and disability of these patients.