Background: N-terminal prohormone of brain natriuretic peptide (NT-proBNP) is known to be correlated with functional capacity of heart failure patients. While the utility of NT-proBNP in asymptomatic apparently healthy population is not well-established, there have been studies on the role of NT-proBNP in screening asymptomatic left ventricular (LV) dysfunction.
Purpose: To evaluate the relationship between cardiorespiratory fitness and NT-proBNP in asymptomatic population.
Methods: The subjects of the study were adults with no history of clinical cardiovascular diseases who had undergone health screening. Those with findings as follows were excluded: abnormal exercise test results, atrial fibrillation on electrocardiogram and left ventricular systolic dysfunction or finding suggestive of cardiomyopathy on echocardiogram. Cardiopulmonary function test was done by modified Bruce protocol and peak oxygen consumptom (VO2peak) was obtained.
Results: Total 9475 men and women were available for analysis. Mean age was 51 ± 7 years, 82% were male, mean VO2peak was 31 ± 5 ml/kg/min, median NT-proBNP was 22.1 (interquartile range 12.8 - 38.9) ng/L. Higher NT-proBNP was associated with older age, female sex, low body mass index, low glomerular filtration rate, low hemoglobin level and hypertension. The negative correlation between log NT-proBNP and VO2peak was significant (r = -0.23, p < 0.001) in bivariate analysis. In multiple regression model, log NT-proBNP was a significant predictor of VO2peak after adjustment for age, gender, hypertension, diabetes, body mass index, lean body mass, hemoglobin, LV mass index, left atrial volume index, E/E` and LV ejection fraction (p < 0.001, R2 = 0.4).
Conclusions: Cardiorespiratory fitness in asymptomatic population was associated with NT-proBNP, which may reflex cardiac dysfunction which is not apparent on echocardiogram but significant enough to influence exercise capacity.