A novel method to predict the proportional risk of sudden cardiac death in heart failure: Derivation of the Seattle Proportional Risk Model

Abstract

Background: Patients with heart failure are at increased risk of both sudden death and pump failure death. Strategies to better identify those who have greatest net benefit from implantable cardioverter-defibrillator (ICD) implantation could reduce morbidity and maximize cost-effectiveness of ICDs.

Objective: We aimed to identify baseline variables in patients with cardiomyopathy that are independently associated with a disproportionate fraction of mortality risk attributable to sudden death vs nonsudden death.

Methods: We used data from 9885 patients with heart failure without ICDs, of whom 2552 died during an average follow-up of 2.3 years. Using commonly available baseline clinical and demographic variables, we developed a multivariate regression model to identify variables associated with a disproportionate risk of sudden death.

Results: We confirmed that lower ejection fraction and better functional class were associated with a greater proportion of mortality due to sudden death. Younger age, male sex, and higher body mass index were independently associated with a greater proportional risk of sudden death, while diabetes mellitus, hyper/hypotension, higher creatinine level, and hyponatremia were associated with a disproportionately lower risk of sudden death. The use of several heart failure medications, left ventricular end-diastolic dimension, or NT-pro brain natriuretic peptide concentrations were not associated with a disproportionate risk of sudden death.

Conclusion: Several easily obtained baseline demographic and clinical variables, beyond ejection fraction and New York Heart Association functional class, are independently associated with a disproportionately increased risk of sudden death. Further investigation is needed to assess whether this novel predictive method can be used to target the use of lifesaving therapies to populations who will derive greatest mortality benefit .

Keywords: Heart failure; ICD; ICD benefit; Nonsudden death; Proportional risk; Regression analysis; Seattle Proportional Risk Model (SPRM); Sudden death.