Background
High NT-proBNP is an established marker of heart failure. However, old individuals have elevated values even when cardiovascularly healthy. Reference values remain scarce.
Objectives
We sought to provide reference values of NT-proBNP for the healthy old and very old population and the proportion above the AHA- and ESC-recommended rule-out cut-off for heart failure diagnosis in a non-acute setting (≥ 125 pg/mL).
Methods
We analyzed cross-sectional data from the population-based AugUR study of inhabitants ≥ 70 years of age. NT-proBNP was determined in serum. Cardiac morphology and function were evaluated by echocardiography.
Results
A total of 2304 subjects aged 70 to 95 years were analyzed (52% women; 35% ≥ 80 years). Median NT-proBNP increased by age group (70–74/75–79/80–84/ ≥ 85 years: 153.0/176.9/228.5/395.0 and 116.1/171.5/217.6/437.0 pg/mL for women or men, respectively); 68% had NT-proBNP ≥ 125 pg/mL. In a subgroup free of cardiovascular risk factors, renal failure, coronary artery disease, and atrial fibrillation (n = 685), 50% (70–79 years) and 70% (≥ 80 years) had NT-proBNP ≥ 125 pg/mL; 97.5% quantiles were considerably higher than 125 pg/mL (70–79 years: 559.5 or 424.5 for women or men; 80–95 years: 809.2 or 722.0 pg/mL for women or men). When further restricting to normal left ventricular mass, E/e′ ratio, and ejection fraction (n = 65), 53% of subjects (70–79 years) or 50% (≥ 80 years) had NT-proBNP ≥ 125 pg/mL.
Conclusions
NT-proBNP levels continue to rise in the very old population. More than 50% of healthy subjects aged 70 years and older have NT-proBNP values above the decision-making cut-off at 125 pg/mL, potentially causing unnecessary further diagnostics and referrals.