The impact of an inverse correlation between plasma B-type natriuretic peptide levels and insulin resistance on the diabetic condition in patients with heart failure

Background. A diabetic state is causally related to heart failure (HF); therefore, there should be a close correlation between the severity of diabetes and HF. However, a direct relationship between these conditions has rarely been reported and remains unclear. This study was designed to precisely examine this relationship, taking into consideration the possible association between natriuretic peptide (NP) levels and insulin resistance. Material and methods. We examined various hemodynamic parameters and simultaneously performed blood biochemical analyses of consecutive patients who underwent cardiac catheterization at our institution (n = 840). Results. Simple regression analyses showed that hemoglobin A1c (HbA1c) levels were not significantly changed by the left ventricular end-diastolic pressure (LVEDP) and left ventricular ejection fraction (LVEF), which were correlated with a low cardiac index. Rather, there was a negative correlation between the HbA1c levels and plasma BNP levels as a marker of HF. A multivariate analysis showed no correlations between the HbA1c levels and cardiac functional parameters (LVEDP, LVEF or the plasma BNP levels), suggesting that the trend toward high HbA1c levels in HF cases is likely to be limited for unknown reasons. To search for an explanation of this finding, we examined the potential biological interactions between BNP and insulin resistance. A multivariate analysis revealed that the plasma BNP levels were positively correlated with age, creatinine levels and LVEDP and inversely correlated with the male gender, body mass index and HOMA-IR (homeostasis model assessment-insulin resistance) (P < 0.001, respectively), but not HbA1c levels. This analysis indicated a close correlation between plasma BNP levels and insulin effectiveness in HF. Conclusions. HF and diabetes tend to worsen with each other; however, the appearance of an association between them was likely blunted due to the considerable effect of NP in counteracting insulin resistance, even during the metabolically harmful condition of HF. (C) 2015 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).