Obese and Nonobese Patients With Essential Hypertension Show Similar N-terminal proBNP Plasma Levels

BACKGROUND: Multiple studies have focused on the influence of obesity on natriuretic peptide levels. However, the effect of obesity on amino-terminal propeptide of B-type natriuretic peptide (NT-proBNP) levels in hypertensive (HT) patients remains uncertain. METHODS: We studied 252 asymptomatic patients (60 +/- 13 years, 136 men) with essential HT. A routine physical examination, anthropometry, laboratory analyses, echo-Doppler study, and NT-proBNP level determination were performed. RESULTS: NT-proBNP levels were similar in both obese and nonobese HT (median 56 (25-130) pg/ml vs. median 51 (26-129) pg/ml, P = 0.488). No significant differences were found in obese or nonobese patients with left ventricular hypertrophy (LVH) (median 135 (73-425) pg/ml vs. median 151 (64-274) pg/ml, P = 0.597). The area under the curve was 0.89 +/- 0.03 for NT-proBNP to diagnose LVH in the obese HT patients and 0.88 +/- 0.03 in the nonobese. A logistic regression analysis showed that age, gender, and left ventricular mass index (LVMI) were independent predictors of NT-proBNP levels. Body mass index (BMI) was not significantly associated with NT-proBNP in LVH HT patients. CONCLUSIONS: Obesity is not statistically associated with NT-proBNP levels in HT asymptomatic patients. The same results were observed in our group of patients with LVH. These data are in contrast with those previously found in heart failure, and raise questions about the role of obesity per se as primary cause of decreased NT-proBNP levels in other pathophysiological conditions.