PORTHOS: NT-proBNP-afkapwaarden onbetrouwbaar bij obese patiënten — risico op gemiste hartfalendiagnose

Background: Obesity is linked to heart failure, particularly with preserved ejection fraction, but is associated with lower natriuretic peptide levels, potentially leading to underdiagnosis. Aims: 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. Methods: 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. Results: 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). Conclusions: 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.