Stratifying the Optimal Thresholds of Point-Of-Care Testing NT-proBNP as Acute Heart Failure Marker in Elder Patients with Impaired Kidney Function

Background: Ageing is characterized by progressive renal dysfunction to varying degrees, but its effect on N-terminal pro-brain natriuretic peptide (NT-proBNP) is vague. We hypothesized that the thresholds of NT-proBNP for heart failure are stratified in elders with different stages of chronic kidney disease (CKD).Methods: In this cross-sectional study, elders aged > 65 with an estimated glomerular filtration rate (eGFR) <60 ml/min for >= 3 months were included. Heart failure with reduced ejection fraction (HFrEF) is defined as a left ventricular ejection fraction (LVEF) is 40% or less and is accompanied by progressive left ventricular dilatation and adverse cardiac remodeling. The receiver operating characteristic (ROC) curves were used to assess the optimal thresholds of NT-proBNP for diagnosing HFrEF.Results: This study analyzed a cohort comprising 1009 patients with CKD (222 cases of stage 3,257 cases of stage 4, and 530 cases of stage 5). Of the subjects, 475 were with HFrEF and 534 without HFrEF. Mean NT-proBNP levels are 3060 pg/ml, 4360 pg/ml, and 16030 pg/ml for CKD stage 3, stage 4, and stage 5 patient groups, respectively. Mean NT-proBNP levels in the HFrEF group were about 4-fold higher compared to the non-HFrEF group. Optimal NT-proBNP cut-offs of HFrEF diagnosis for CKD stage 3, stage 4, and stage 5 were 1420 pg/ml, 2540 pg/ml, and 19800 pg/ml, respectively.Conclusions: NT-proBNP was elevated in advance staged CKD even in the absence of HFrEF, and the magnitude of increase in NT-proBNP was significant in the elderly population. Using higher thresholds according to CKD stages, NT-proBNP can help diagnose HFrEF.Copyright (c) 2023, Taiwan Society of Geriatric Emergency & Critical Care Medicine.