Reasons why patients suffering from chronic heart failure at very low risk for mortality die

Background A proper prognostic stratification is crucial for organizing an effective clinical management and treatment decision-making in patients with chronic heart failure (CHF). In this study, we selected and characterized a sub-group of CHF patients at very low risk for death aiming to assess predictors of death in subjects with an expected probability of 1-year mortality near to 5%. Methods We used the Cardiac and Comorbid Conditions HF (3C-HF) Score to identify CHF patients with the best mid-term prognosis. We selected patients belonging to the lowest quartile of 3C-HF score (≤ 9 points). Results We recruited 1777 consecutive CHF patients at 3 Italian Cardiology Units (age 76 ± 10 years, 43% female, 32% with preserved ejection fraction). Subjects belonging to the lowest quartile of 3C-HF score were 609. During a median follow-up of 21 [12–40] months, 48 of these patients (8%) died, and 561 (92%) survived. The variables that contributed to death prediction by Cox regression multivariate analysis were older age (HR 1.03[CI 1.00–1.07]; p = 0.04), male gender (HR 2.93[CI 1.50–5.51]; p = 0.002) and a higher degree of renal dysfunction (HR 0.96[CI 0.94–0.98]; p < 0.001). Conclusions The prognostic stratification of CHF patients by 3C-HF score allows one to select patients at different outcome and to identify the factors associated with death in outliers with a very low mortality risk at mid-term follow-up. The reasons why these patients do not outlive the matching part of subjects who expectedly survive are related to a declined renal function and unmodifiable conditions including older age and male gender.