A severity index study of long-term prognosis in patients with chronic heart failure

Abstract

Aims: The present study describes the derivation and validation of the Chronic Heart Failure Severity Index (CHFSI).

Main methods: The CHFSI was derived using data obtained from a single-center prospective cohort study (2000-2014) that enrolled 756 patients. Logistic regression was used to identify independent predictors of mortality and quality of life over a 15-year follow-up period.

Key findings: The score was validated at the first 5-year (n = 644), second 5-year (n = 364), and third 5-year (n = 262). Independent predictors of mortality were older age (OR = 2.04, P < 0.001), etiology score (OR = 2.61, P < 0.001), faster heart rate (OR = 1.46, P = 0.027), higher systolic blood pressure (OR = 2.35, P < 0.001), and left ventricular ejection fraction ≤45% (OR = 1.97, P = 0.018). The derived CHFSI predicted the mortality, and the AUC for the logistic model was 0.78 (95% confidence interval = 0.74-0.81, P < 0.001). Based on the logistic model, an integer scoring system was derived. Patients were classified into three groups: low risk (0-7 points), intermediate risk (8-11 points) and high risk (≥12 points) groups. The cumulative mortality for 15 years was 45.5% (125/275), 84.0% (204/243), and 100% (99/99), respectively (P < 0.001). The 6-min walk test revealed a significant difference in quality of life among patients in the low, medium and high risk groups (all, P < 0.0001).

Significance: The CHFSI is a very useful clinical predictive tool that identifies patients at risk of future mortality and their quality of life across healthcare systems.

Keywords: 6-min walk test; Heart failure; Mortality; Quality of life.