Prognostic role of B-type natriuretic peptide levels in patients with type 2 diabetes mellitus

OBJECTIVES We hypothesized that B-type natriuretic peptide (BNP) levels can predict cardiac mortality in diabetic patients. BACKGROUND Detection of cardiovascular disease in diabetics can be difficult until overt events occur. METHODS A total of 482 diabetics (majority male with type 2 diabetes) at the Veterans Affairs Medical Center San Diego were divided into two groups: 1) referred patients for echocardiogram on the basis of clinical suspicion of cardiac dysfunction (referred [R], n = 180); 2) patients randomly selected from the diabetic clinic without any suspicion of cardiac dysfunction (not referred [N-R], n = 302). We examined cardiac events and all-cause mortality in relation to initial BNP levels during the follow-up. RESULTS A total of 71 (14.7%) patients died during this period: 52 of 180 (29%) in the R group (30 of 52 [58%] cardiac, 10 of 52 [19%] non-cardiac, 2 of 52 [4%] renal, 10 of 52 [19%] unknown cause) and 19 of 302 (6%) in N-R group (6 of 19 [32%] cardiac). The median BNP level in the R and N-R groups who died of cardiac, non-cardiac, and unknown cause was 537 and 87, 80 and 53, and 343 and 38 pg/ml, respectively. The receiver-operating characteristic (ROC) values for mortality in two groups in relation to BNP revealed the area under the curve to be 0.720 and 0.691, respectively (p < 0.01 in both). Among commonly used prognostic indicators in diabetics, only the ROC for triglycerides was significant. The most accurate cut-point in both the N-R group (87%) and R group (61%) was 120 pg/ml of BNP. Cox regression analysis showed BNP to be the most significant predictor of all-cause mortality in the R group. There was a marked decrease in survival in the patient group with BNP >120 pg/ml. CONCLUSIONS B-type natriuretic peptide appears to be a reliable predictor of future cardiac and all-cause mortality in diabetic patients. (C) 2004 by the American College of Cardiology Foundation.