Serum beta2-microglobulin concentration as a novel marker to distinguish levels of risk in acute heart failure patients

Background: Recently, serum beta2-microglobulin, an endogenous marker for renal function, has been shown to be an independent predictor of mortality in older adults. However, the prognostic role of beta2-microglobulin in heart failure has not been elucidated. Methods: We prospectively evaluated serum beta2-microglobulin and creatinine concentrations, creatinine-based renal parameters (estimated glomerular filtration rate and creatinine clearance), and echocardiographic data in 131 patients with acute heart failure and creatinine concentrations <= 3.0 mg/dL admitted to our hospitals. Results: During 2.3 +/- 1.3 years, 42 patients died of cardiovascular causes and 12 died of non-cardiac causes. Cardiovascular events were observed in 63 patients: 53 were readmitted due to worsening heart failure, 5 readmitted for cerebral embolism, and 5 died from sudden cardiac death. According to multivariate stepwise Cox proportional hazard analysis, higher baseline serum beta2-microglobulin concentrations (X(2) = 16, p < 0.0001), previous congestive heart failure (X(2) = 11, p < 0.001), presence of chronic obstructive pulmonary disease (X(2) = 8, p < 0.01), and tower diastolic blood pressure (X(2) = 6, p < 0.05) were independent predictors of increased cardiovascular events. Also, higher baseline serum beta2-microglobulin (X(2) = 20, p < 0.0001), lower systolic blood pressure (X(2) = 11, p < 0.001), higher relative left ventricular wall thickness (X(2) = 6, p < 0.05), and tower body mass index (X(2) = 5, p < 0.05) were independent predictors of increased cardiac mortality. The adjusted hazard ratio for cardiovascular events increased with baseline serum beta2-microglobulin above 2.1 mg/L: 2.9 with beta2-microglobulin of 2.2-2.6 mg/L (95%CI 1.2-6.9, p < 0.05), 2.9 with beta2-microglobulin of 2.7-3.9 mg/L (95%CI 1.2-7.2, p < 0.05), and 4.7 with beta2-microglobulin of >= 4.0 mg/L (95%CI 2.0-11, p < 0.001). Conclusions: Higher baseline serum beta2-microglobulin concentration could be a promising risk marker in acute heart failure patients with creatinine <= 3.0 mg/dL. (C) 2009 Japanese College of Cardiology. Published by Elsevier Ireland Ltd. All rights reserved.