B-type natriuretic peptide levels and insulin resistance in patients with severe ischemic myocardial dysfunction.

B-type natriuretic peptide (BNP) is an important clinical parameter of severity in congestive heart failure (CHF). Recent findings suggest a close relation between lipid and glucose metabolism and the natriuretic peptide axis, even if conflicting data exist on the relationship between natriuretic peptide levels and insulin resistance (IR). Thus, we sought to investigate potential relations between BNP level and IR in 134 patients with severe ischemic myocardial dysfunction [mean+/-SD: age =64.8+/-9.6 yr, male/female =104/30; body mass index (BMI) =25.5+/-4.05 kg/m2, 26.1% diabetics; ejection fraction (EF) = 30.2+/-7.7%]. In univariate analysis, an inverse relationship between BNP levels and EF% was observed (R=-0.43, p=0.0006). Moreover, we found an inverse association between BNP levels and BMI (R=-0.27, p=0.036), and also between BNP and homeostasis model assessment of insulin resistance (HOMA-IR) (R=-0.27, p=0.039). In multivariate analysis, EF% and HOMA-IR were significantly and independently associated with logarithmically transformed BNP levels (beta=-0.40, p=0.019 and beta=-0.26, p=0.042, respectively; R2=0.36). In conclusion, in patients with severe ischemic myocardial dysfunction EF and IR are independently associated with BNP levels explaining about 1/3 of the variability of this parameter. Multiple potential mechanisms may underlie this association, but it seems now clinically important to take into account also metabolic features when interpreting plasma natriuretic peptide concentrations obtained for diagnostic or prognostic purposes.