Serum ST2 and hospitalization rates in Caucasian and African American outpatients with heart failure

Abstract

BackgroundLimited data exist on the association between circulating suppression of tumorigenicity 2 (ST2) and recurrent hospitalizations and emergency department (ED) encounters in outpatients with heart failure (HF). In addition, data on ST2 in African American patients with HF are scarce. MethodsWe evaluated 307 outpatients with HF (age, 57 ± 12 years; 64.2% men; 51.5% Caucasian, 45.6% African American; median ejection fraction, 35%; ischemic etiology, 41.4%). Median ST2 was 37.8 ng/mL (29.6–51.4). ResultsAfter a median of 3.1 years, there were 584 hospitalizations (224 for HF) and 335 ED visits (80 for HF). Patients (N = 176; 57.3%) with elevated (>35 ng/mL) ST2 had 2-fold higher hospitalization rates in adjusted models (rate ratio [RR] 1.97; 95% CI 1.38–2.82; P < 0.001), driven by 3.5-fold higher HF hospitalization rates (adjusted RR 3.56; 95% CI 1.69–7.49; P < 0.001). These associations persisted after adjusting for baseline B-type natriuretic peptide levels. Findings were similar for elevated ST2 and ED visit rates. Elevated ST2 was associated with the composite of death or HF hospitalization (109 patients; 3-year estimate: 35.4%); risk was 5-fold higher in the first 6 months but declined gradually. The higher hospitalization rates and composite endpoint risk associated with elevated ST2 was similar in African Americans and Caucasians. In landmark analyses in a subset of patients, 6-month (N = 112) and 12-month (N = 149) changes in ST2 levels from baseline added prognostic information. ConclusionsElevated ST2 in outpatients with HF portends higher healthcare resources utilization and higher risk for accelerated disease progression, regardless of race, especially in the first 6 months.