β-Trace Protein and Cystatin C as Predictors of Long-Term Outcomes in Patients With Acute Heart Failure

Objectives The purpose of this study was to evaluate the prognostic importance of novel markers of renal dysfunction among patients with acutely destabilized heart failure (ADHF). Background beta-trace protein (BTP) and cystatin C are newer biomarkers for renal dysfunction; the prognostic importance of these tests, particularly BTP, relative to standard measures of renal function remains unclear. Methods A total of 220 consecutive hospitalized patients with ADHF were prospectively studied. Blood samples were collected on presentation. In-hospital worsening renal function, as well as mortality and/or heart failure (HF) hospitalization, over a median follow-up period of 500 days was examined as a function of BTP or cystatin C concentrations; results were compared with creatinine, estimated glomerular filtration rate, and blood urea nitrogen. Results Neither BTP nor cystatin C was associated with worsening renal function during the index hospitalization. A total of 116 patients (53%) either died or were hospitalized for HF during follow-up. Those with adverse outcomes had higher BTP (1.04 mg/l [range 0.80 to 1.49 mg/l] vs. 0.88 mg/l [range 0.68 to 1.17 mg/l], p = 0.003) and cystatin C (1.29 mg/l [range 1.00 to 1.71 mg/l] vs. 1.03 mg/l [range 0.86 to 1.43 mg/l], p = 0.001). After multivariable adjustment, both BTP (hazard ratio: 1.41, 95% confidence interval: 1.06 to 1.88; p = 0.018) and cystatin C (hazard ratio: 1.50, 95% confidence interval: 1.13 to 2.01; p = 0.006) were significant predictors of death/HF hospitalization, whereas serum creatinine, estimated glomerular filtration rate, and blood urea nitrogen were no longer significant. In patients with an estimated glomerular filtration rate >60 ml/min/1.73 m(2), elevated concentrations of BTP and cystatin C were still associated with significantly higher risk of adverse clinical events (p < 0.05). Net reclassification index analysis suggested cystatin C and BTP deliver comparable information regarding prognosis. Conclusions Among patients hospitalized with ADHF, BTP and cystatin C predict risk of death and/or HF hospitalization and are superior to standard measures of renal function for this indication. (J Am Coll Cardiol 2011; 57: 849-58) (C) 2011 by the American College of Cardiology Foundation