Predicting Mortality Among Patients Hospitalized for Heart Failure: Derivation and Validation of a Clinical Model

Abstract

CONTEXT: A predictive model of mortality in heart failure may be useful for clinicians to improve communication with and care of hospitalized patients. OBJECTIVES: To identify predictors of mortality and to develop and to validate a model using information available at hospital presentation. DESIGN, SETTING, AND PARTICIPANTS: Retrospective study of 4031 community-based patients presenting with heart failure at multiple hospitals in Ontario, Canada (2624 patients in the derivation cohort from 1999-2001 and 1407 patients in the validation cohort from 1997-1999), who had been identified as part of the Enhanced Feedback for Effective Cardiac Treatment (EFFECT) study. MAIN OUTCOME MEASURES: All-cause 30-day and 1-year mortality. RESULTS: The mortality rates for the derivation cohort and validation cohort, respectively, were 8.9% and 8.2% in hospital, 10.7% and 10.4% at 30 days, and 32.9% and 30.5% at 1 year. Multivariable predictors of mortality at both 30 days and 1 year included older age, lower systolic blood pressure, higher respiratory rate, higher urea nitrogen level (all P<.001), and hyponatremia (P<.01). Comorbid conditions associated with mortality included cerebrovascular disease (30-day mortality odds ratio [OR], 1.43; 95% confidence interval [CI], 1.03-1.98; P =.03), chronic obstructive pulmonary disease (OR, 1.66; 95% CI, 1.22-2.27; P =.002), hepatic cirrhosis (OR, 3.22; 95% CI, 1.08-9.65; P =.04), dementia (OR, 2.54; 95% CI, 1.77-3.65; P<.001), and cancer (OR, 1.86; 95% CI, 1.28-2.70; P =.001). A risk index stratified the risk of death and identified low- and high-risk individuals. Patients with very low-risk scores (< or =60) had a mortality rate of 0.4% at 30 days and 7.8% at 1 year. Patients with very high-risk scores (>150) had a mortality rate of 59.0% at 30 days and 78.8% at 1 year. Patients with higher 1-year risk scores had reduced survival at all times up to 1 year (log-rank, P<.001). For the derivation cohort, the area under the receiver operating characteristic curve for the model was 0.80 for 30-day mortality and 0.77 for 1-year mortality. Predicted mortality rates in the validation cohort closely matched observed rates across the entire spectrum of risk. CONCLUSIONS: Among community-based heart failure patients, factors identifiable within hours of hospital presentation predicted mortality risk at 30 days and 1 year. The externally validated predictive index may assist clinicians in estimating heart failure mortality risk and in providing quantitative guidance for decision making in heart failure care.