Impact of age and renal function on usefulness of NT-proBNP to diagnose heart failure

Aims: NT-proBNP is a useful biomarker for heart failure (HF) diagnosis. We aimed to determine NT-proBNP's ability to diagnose HF by age and renal function. Materials and methods: We analyzed 3,699 consecutive and unique adults admitted for dyspnea at the Emergency Unit of St. Joseph St. Luc Hospital, Lyon, France, from December 1, 2012 to June 30, 2016, who had concomitant measurement of NT-proBNP and serum creatinine. We excluded patients with acute coronary syndrome and dialysis patients. Receiving operating characteristic (ROC) analysis assessed ability and cutoff points of NT-proBNP to diagnose HF. Results: Mean age was 79.1 +/- 13.0 years. Mean estimated glomerular filtration rate (eGFR, CKD EPI formula) was 64 +/- 26 mL/min/1.73m(2). The ROC area under the curve (AUC) was 0.813 on average, optimal NT-proBNP cut-off point was 1,896 ng/L. AUC decreased (0.882, 0.813, 0.767) by age class (18 -69, 70 -84, 85+ years, respectively), and optimal cut-off points increased (1,041, 1,902, 2,321 ng/L). AUC decreased (0.881, 0.830, 0.783, 0.781, 0.705) by eGFR class (>= 90, 60 -89, 45 -59, 30 -44, < 30 mL/min/1.73m(2)), and cut-off points increased (757, 1,362, 2,283, 4,108, 7,288 ng/L). The lowest value of cut-off points associated with highest sensitivity and specificity was detected in young patients with eGFR >= 90 (597 ng/L) while the worst value was found in age 85+ patients with eGFR < 30 (7,288 ng/L). AUC decreased below 0.8 in age 70+ patients with eGFR < 45 mL/min/1.73m(2). Conclusion: The ability of NT-proBNP to diagnose HF decreased strongly with age and renal function. NT-proBNP's usefulness in diagnosing HF in age 70+ patients with eGFR < 45 mL/min/1.73m(2) remains uncertain.