Not All “Negatives” Are Created Equal — Understanding the Impact of Body Mass Index on B-Type Natriuretic Peptide Interpretation in Heart Failure

Heart failure (HF) is a significant cause of morbidity and mortality in the USA with an increasing economic burden. Recent data show an increased incidence of death and hospitalizations related to HF.¹ Concomitantly, advances in HF diagnosis have led to the ability to identify HF earlier in the disease process. Secreted by cardiac myocytes in response to increased wall stress, B-type natriuretic peptide (BNP) can provide valuable information in the diagnosis of suspected HF.^2‐4 However, multiple variables have been shown to modify BNP levels and complicate its interpretation. Female sex, older age, renal disease, and atrial fibrillation have all been independently associated with increased BNP levels.^5,6 Additionally, body mass index (BMI) has been found to have an inverse relationship with BNP, though the mechanism is unclear. Several postulations include increased glomerular filtration rate and increased clearance by adipose tissue, though without definitive evidence.^6,7 Correct application of the BNP test characteristics in patients with high BMI can be challenging. …