PORTHOS (Portugal, population-based, age ≥50, n=2,498) shows NT-proBNP is systematically lower in obesity — ~50 pg/mL lower per 5 kg/m² BMI increase. Obese participants with NT-proBNP <125 pg/mL had higher odds of HF symptoms (OR 1.97) and echo abnormalities (OR 3.63) than lean participants above the cut-off, despite being 9 years younger and having 4x lower NT-proBNP (59 vs 235 pg/mL). Fixed cut-offs miss HF in obesity; primary-care screening pathways need adjustment.
Obesity is linked to heart failure, particularly with preserved ejection fraction, but is associated with lower natriuretic peptide levels, potentially leading to underdiagnosis.
To examine the association between adiposity measures — body mass index, waist circumference, and waist-to-height ratio — and N-terminal pro-B-type natriuretic peptide levels, and to determine if lower cut-offs should be used to rule out heart failure in individuals with obesity.
PORTHOS is a 2023 population-based study in Portugal including adults aged 50 years or older. Participants underwent NT-proBNP screening, followed by clinical and echocardiographic assessment in those with levels ≥125 pg/mL, self-reported heart failure, or a 5% random sample with levels <125 pg/mL.
Among 2,498 participants, obesity prevalence ranged from 25% using body mass index ≥30 kg/m² to >70% using waist-to-height ratio ≥0.6. Body mass index showed a strong inverse association with NT-proBNP, with approximately 50 pg/mL lower levels per 5 kg/m² increase. Individuals with obesity and NT-proBNP <125 pg/mL had higher odds of heart-failure symptoms (OR 1.97, 95% CI 1.15–3.38) and echocardiographic abnormalities (OR 3.63, 95% CI 1.27–10.4) than lean participants with NT-proBNP ≥125 pg/mL — despite being 9 years younger and having fourfold lower median NT-proBNP (59 vs 235 pg/mL).
Obesity is associated with lower NT-proBNP levels despite a higher burden of symptoms and structural abnormalities. Fixed cut-offs do not reliably exclude heart failure in individuals with obesity.
