NPPB and obesity due to melanocortin 4 receptor deficiency: This may be due to the high prevalence of obesity in HFpEF populations, as disproportionately low BNP and NT-proBNP levels have been reported in obese patients, which may be related to the mechanisms involving natriuretic peptide degradation in adipose tissue, insulin resistance, and enhanced pericardial restraint (32, 34–37).