NT-proBNP in the very old population: reference values and heart failure specificity from the AugUR-study

High NT-proBNP is an established marker of heart failure. However, old individuals have elevated values even when cardiovascularly healthy. Reference values remain scarce.

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).

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.

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.

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.