Cystatin C as Marker of Cardiorenal Syndrome and Poor Prognosis in Patients Hospitalized with Acute Heart Failure and Normal Renal Function

Background: The development of renal dysfunction in patients hospitalized for acute heart failure is known as cardiorenal syndrome type 1 (CRS). Worsening renal function (WRF) during hospitalization is associated with poor prognosis. Cystatin C has emerged as an alternative renal function marker to creatinine. Objective: The aim of this study was to demonstrate the usefulness of cystatin C as predictor of WRF and prognostic factor in pa-tients with acute heart failure and normal renal function assessed by creatinine level on admission.Methods: A prospective, observational study was performed on consecutive patients with acute heart failure and normal renal func-tion defined as serum creatinine <1.3 mg/dL on admission. Cystatin C was measured on admission. The primary endpoint was WRF, and secondary endpoints were in-hospital mortality, total mortality and rehospitalization for heart failure.Results: A total of 166 patients were included in the study. Median age was 85 years (IQR 77.7- 89 years). The incidence of WRF was 29.7%, with in-hospital mortality of 3.1% and total mortality of 24.4%. Median follow-up was 193 days. Serum cystatin C was signifi-cantly higher in patients who developed WRF (1.72±0.58 mg/dL vs. 1.51±0.41 mg/dL, p=0.03) and in patients who died during fol-low up (1.76±0.49 vs. 1.51±0.46, p=0.004). Multivariate analysis showed that cystatin C was an independent predictor of mortality (OR 3.03, 95% CI 1.22-7.47) and WRF (OR 2.38, 95% CI 1.02-5.5). The optimal cystatin C cutoff point was 1.6 mg/dL, with 61.22% sensitivity and 60.34% specificity for the development of WRF, and 61.54% sensitivity and 61.98% specificity for total mortality. Conclusions: Cystatin C on admission is a predictor of in-hospital WRF and increased mortality in this population hospitalized with acute heart failure and preserved renal function.