Abstract Background N-terminal pro-B-type natriuretic peptide (NT-proBNP) is a biomarker used for the diagnosis of heart failure. There is a relationship between NT-proBNP levels and body mass index (BMI). The study aimed to explore the impact of BMI on NT-proBNP concentrations and to examine whether other factors independent of or combined with BMI affect NT-proBNP values in patients with heart failure. Results A total of 293 participants were recruited. The mean age was 68.9 ± 13.2 years, males accounted for 46.4% of the total cohort, the mean BMI was 23.1 ± 4.0 kg/m2, and the median NT-proBNP level was 3776 (1672–8806) pg/ml. There was an inverse relationship between BMI and log NT-proBNP (r = − 0.29; p