Background: Biomarkers play an important role in the risk stratification of patients with heart failure (HF). Recent studies have shown that soluble suppression of tumorigenicity 2 (sST2), a member of the interleukin 1 receptor family, is associated with disease prognosis in acute and chronic HF. In this study we aimed to investigate the relation between sST2 level and functional capacity in outpatients with systolic HF.
Patients and methods: This study included 120 HF patients with reduced ejection fraction (HFrEF; EF ≤ 40%). The mean age of patients was 66 ± 11 years. Advanced HF (New York Heart Association [NYHA] functional class III-IV) was observed in 35 patients (29%).
Results: sST2 levels were on average higher in patients with NYHA functional classes III and IV than in patients with NYHA functional classes I and II (51 [9-198] vs. 25 ng/ml [9-118], p < 0.001). In a multiple logistic regression model, sST2 level (OR: 1.044, p = 0.004, 95% CI: 1.014-1.075), hemoglobin level (OR: 0.590, p = 0.001, 95% CI: 0.433-0.805), total cholesterol level (OR: 0.977, p = 0.004, 95% CI: 0.962-0.993), and age (OR: 1.066, p = 0.047, 95% CI: 1.001-1.136) were associated with poor functional capacity. In receiver operating characteristic (ROC) curve analysis, the optimal cut-off value of sST2 for predicting poor functional capacity was >42 ng/ml, with 63% sensitivity and 88% specificity (AUC: 0.810, 95% CI: 0.728- 0.875).
Conclusion: Higher sST2 levels were strongly associated with poor NYHA functional class, independent of cardiac risk factors, in outpatients with HFrEF.
Keywords: Biomarkers; Exercise tolerance; Hospitalization; Outpatients; Systolic heart failure.