A comparison of NT-proBNP and albuminuria for predicting cardiac events in patients with diabetes mellitus

Aims: Cardiovascular events are the most relevant events in patients with diabetes mellitus. We aimed to compare the predictive values of N-terminal pro-brain natriuretic peptide (NT-proBNP) and the state-of-the-art marker, albuminuria, for cardiac events in diabetic patients. Methods: In this prospective observational study we recruited 1071 patients with diabetes mellitus. NT-proBNP and albuminuria - defined as a urinary albumin/creatinine ratio >30 mg/g - were measured at baseline. Patients were followed during a mean observation period of 33.1 months. A total of 103 patients reached the defined endpoint (unplanned hospitalization due to a cardiac event or death). Results: The mean duration of diabetes was 15 +/- 12 years and the mean HbA(1c) was 7.5 +/- 3.1%. At baseline, 23.7% of the patients presented with albuminuria and 36.6% had plasma NT-proBNP values > 125 pg/ml. Multiple Cox regression analysis including age, gender, duration of diabetes HbA(1c), albuminuria, and lnNT-proBNP revealed that lnNT-proBNP (hazard ratio 2.314; 95% CI 1.914-2.798, p < 0.001) was a better predictor than albuminuria (HR 1.544; 95% CI 1.007-2.368, p = 0.047) or age (HR 1.030; 95% CI 1.008-1.053, p = 0.007). Calculating different Cox-models with (A) albuminuria, (B) NT-proBNP, or (C) both in the model revealed that the C-index was best if NT-proBNP was entered in the model (C-index for A 0.735, for B 0.809, and for C 0.786). Kaplan-Meier analysis demonstrated that albuminuria does not add substantial information if NT-proBNP is entered into the model. Conclusion: NT-proBNP was superior to albuminuria for predicting cardiac events.