Which condition tends to lower BNP/NT-proBNP levels, potentially masking heart failure?

• A. Obesity lowers BNP/NT-proBNP levels.
• B. Atrial fibrillation lowers BNP levels.
• C. Renal failure lowers BNP levels.
• D. Age lowers BNP levels.

Answer: (A)

BNP and NT-proBNP rise with ventricular wall stress and help diagnose heart failure, but obesity tends to lower these peptide levels. The reason is that adipose tissue has more natriuretic peptide clearance receptors (NPR-C) and may also promote greater peptide degradation, so circulating BNP gets cleared more quickly in individuals with higher body fat. This can blunt the expected rise in BNP/NT-proBNP even when heart failure is present, masking the diagnosis. In contrast, conditions like atrial fibrillation or advancing age usually increase BNP because they add to wall stress or baseline peptide production, while renal failure tends to raise BNP due to reduced clearance. So obesity is the factor that most commonly lowers BNP/NT-proBNP levels and can mask heart failure.