POS-368 DOES NT-PROBNP VARIABILITY PREDICT RENAL AND CARDIOVASCULAR ADVERSE EVENTS IN PATIENTS WITH CKD STAGE G4-5?

Abstract

NT-proBNP levels correlate with fluid overload and cardiac dysfunction in CKD patients. While baseline NT-proBNP levels are associated with adverse renal and cardiovascular (CV) events, whether the variability of this biomarker over time influences risk prediction in patients with advanced CKD remains to be determined. We thus aimed to characterise the association between NT-proBNP variability and major adverse events. We measured NT-proBNP in patients with CKD G4-5 at two consecutive advanced kidney care clinic appointments and followed them for a minimum of one year. Participants were categorised according to whether a change in NT-proBNP levels occurred between baseline and the follow-up visit (Group 1, decrease ≥10%; Group 2, stable levels; Group 3, increase ≥10%). The primary outcome was a composite of renal (≥40% estimated glomerular filtration rate decline, need for replacement therapy or death from renal causes) and CV (myocardial infarction, hospitalisation for heart failure, stroke or CV death) events, starting from the date of the second NT-proBNP measurement. Cox proportional hazard regressions adjusted for baseline NT-proBNP level were used. We included 127 participants with CKD G4-5 and a median follow-up of 11.1 (IQR 6.8-12.5) months (or 101 patient-years). The median baseline eGFR and NT-proBNP level were 19 (15-23) mL/min/1.73m2 and 1125 (IQR 398-3217) ng/L, respectively. Baseline characteristics were similar across the tree exposure groups. Major adverse events occurred in 20 (51%) of the 39 patients in Group 1 (decreasing levels), 7 (29%) of the 24 in Group 2 (stable levels) and 23 (36%)of the 64 in Group 3 (increasing levels). Compared to patients in Group 2, those in Groups 1 and 3 had similar risks of adverse events [HR 2.02 (95% CI 0.85-4.82), p=0.11 and HR 1.50 (95% CI 0.61-3.69), p=0.38, respectively]. In patients with CKD stage G4-5, variability in NT-proBNP levels was not associated with an increased risk of renal or cardiovascular adverse events. albeit this study may not have sufficient power to detect such a difference. Whether NT-proBNP levels monitoring can improve the management of advanced CKD remains to be determined.