New research suggests moderate to severe depression could up depression risk five-fold in patients also suffering from heart failure.

The increases death risk encompasses death from all causes, and it is independent of risks associated with comorbidities and severity of heart failure, the European Society of Cardiology reported. The findings suggest heart failure patients who were not depressed had an 80 percent reduced risk of death.

"Patients with heart failure are at high risk of recurrent hospital admissions and death. Approximately 25 [percent] of patients admitted to hospital with heart failure are readmitted for a variety of reasons within one month. Within one year, most patients will have had one or more readmissions and almost half will have died," said professor John Cleland, chief investigator of OPERA-HF and professor of cardiology at Imperial College London and the University of Hull.

"OPERA-HF was designed to investigate in a more holistic fashion than previously the predictors of and reasons for readmission and death amongst patients with heart failure. This included social, mental and physical frailty, as well as comorbidities and the severity of heart failure. Depression has been reported to predict death in patients with heart failure but until now it was thought that this could be because depressed patients have more severe heart failure and more comorbidities," Cleland said.

The study looked at 150 patients, 103 of which were depressed. Out of this group, 27 with mild depression and 24 had moderate to severe depression. Over a mean follow up of 302 days, 27 patients died. Depression levels were assessed using the Hospital Anxiety and Depression Scale (HADS-D) questionnaire and comorbidity was examined using the Charlson Comorbidity Index (CCI).

"We know that depression is common in heart failure and affects [20 to 40 percent] of patients.1 Depression is often related to loss of motivation, loss of interest in everyday activities, lower quality of life, loss of confidence, sleep disturbances and change in appetite with corresponding weight change. This could explain the association we found between depression and mortality," Cleland said. 

The findings of the OPERA-HF study will be presented at Heart Failure 2015, which is the main annual meeting of the Heart Failure Association (HFA) of the European Society of Cardiology (ESC).