Background: N-terminal pro-B-type natriuretic peptides (NT-proBNPs) are guideline-recommended biomarkers for risk stratification in patients with heart failure. However, NT-proBNP levels are often elevated in chronic kidney disease, introducing uncertainty about their prognostic relevance in persons across a broad range of estimated glomerular filtration rate (eGFR)., Objectives: The aim of this study was to assess the association of NT-proBNP with cardiovascular and mortality outcomes in patients with heart failure and mildly reduced or preserved ejection fraction, stratified by baseline kidney function., Methods: A pooled analysis was conducted of participants with NT-proBNP and eGFR measured at baseline in the I-PRESERVE (Irbesartan in Heart Failure and Preserved Ejection Fraction), TOPCAT (Americas region) (Aldosterone Antagonist Therapy for Adults With Heart Failure and Preserved Systolic Function), PARAGON (Prospective Comparison of ARNI with ARB Global Outcomes in HF With Preserved Ejection Fraction), and DELIVER (Dapagliflozin Evaluation to Improve the LIVEs of Patients With PReserved Ejection Fraction Heart Failure) trials. The relationship between NT-proBNP and eGFR was assessed using piecewise linear regression. Using multivariable Cox and Poisson regression models, the association of NT-proBNP with outcomes across a range of eGFR was evaluated. The primary outcome was hospitalization for heart failure or cardiovascular death., Results: Among 14,831 participants (mean age: 72.1 years; 50.3% female; mean eGFR: 63.3 mL/min/1.73 m 2 , and median NT-proBNP: 840 pg/mL) followed up for a median 33.5 months, there were 3,092 primary outcomes. NT-proBNP levels increased by 9%, 8%, and 23% per 10 mL/min/1.73 m 2 lower eGFR in patients with baseline eGFR ≥60, 45-<60, and <45 mL/min/1.73 m 2 , respectively (P for nonlinearity < 0.001). Each doubling in NT-proBNP was associated with a 37% relative increase in the primary outcome (HR: 1.37; 95% CI: 1.34-1.41), consistent across different eGFR categories (P for interaction = 0.42). For the same incidence of the primary outcome, NT-proBNP levels were approximately 2.5- to 3.5-fold lower in patients with eGFR <45 mL/min/1.73 m 2 , compared with patients with eGFR ≥60 mL/min/1.73 m 2 . Similar patterns were observed across all outcomes studied, including cardiovascular and noncardiovascular death., Conclusions: The same NT-proBNP concentration predicts a substantially higher absolute risk of adverse outcomes for people with heart failure and reduced kidney function, compared with those with preserved kidney function. These data call into question proposals for higher NT-proBNP references ranges in people with CKD, and suggest that reduced kidney function per se should not be a reason to disregard higher NT-proBNP levels., Competing Interests: Funding Support and Author Disclosures Dr Neuen is supported by an Australian National Health and Medical Research Council Emerging Leader Investigator Grant (grant number 2026621) and a Ramaciotti Foundation Health Investment Grant (grant number 2023HIG69). The funders had no role in the writing of the manuscript or decision to submit for publication. Dr Neuen has received fees for travel support, advisory boards, and scientific presentations from AstraZeneca, Bayer, Boehringer and Ingelheim, Cambridge Healthcare Research, Cornerstone Medical Education, the Limbic, Janssen, Medscape, Novo Nordisk, and Travere Therapeutics; and has served on clinical trial committees for studies sponsored by AstraZeneca, Bayer, and CSL Behring. Dr Vaduganathan has received research grant support, served on advisory boards, or had speaker engagements with American Regent, Amgen, AstraZeneca, Bayer AG, Baxter Healthcare, BMS, Boehringer Ingelheim, Chiesi, Cytokinetics, Fresenius Medical Care, Idorsia Pharmaceuticals, Lexicon Pharmaceuticals, Merck, Milestone Pharmaceuticals, Novartis, Novo Nordisk, Pharmacosmos, Relypsa, Roche Diagnostics, Sanofi, and Tricog Health; and has participated on clinical trial committees for studies sponsored by AstraZeneca, Galmed, Novartis, Bayer AG, Occlutech, and Impulse Dynamics. Dr Claggett has received consulting fees from Alnylam, Cardior, Cardurion, Corvia, CVRx, Cytokinetics, Intellia, Rocket, and Valo. Dr Beldhuis is supported by the Junior clinical scientist grant by the Dutch Heart Foundation; her employer is supported by an unrestricted medical grant by Novartis. Dr Myhre has served on advisory boards or had speaker engagements with Amarin, AmGen, AstraZeneca, Bayer, Boehringer-Ingelheim, Bristol Myers Squibb, Novartis, Novo Nordisk, Pharmacosmos, Roche, Sanofi, US2.ai, and Vifor. Dr Desai has received honoraria for consulting or speaking from Abbott, AstraZeneca, Alnylam, Avidity Biopharma, Axon Therapeutics, Bayer, Biofourmis, Boston Scientific, GlaxoSmithKline, Medpace, Medtronic, Merck, New Amsterdam Pharma, Novartis, Parexel, Regeneron, River2Renal, Roche, scPharmaceuticals, Verily, Veristat, and Zydus; and has received institutional research grant support from Abbott, Alnylam, AstraZeneca, Bayer, Novartis, and Pfizer. Dr Mc Causland has received research funding from the National Institute of Diabetes and Digestive and Kidney Diseases, Satellite Healthcare, Fifth Eye, Novartis, and Lexicon, which is paid directly to his institution; and he has received consulting fees from GlaxoSmithKline and Zydus Therapeutics. Dr McGrath has received research funding from Lexicon Pharmaceuticals and has served as a consultant to Alexion. Dr Anand has received consultancy fees from Amgen, ARCA, AstraZeneca, Boehringer Ingelheim, Boston Scientific, LivaNova, Novartis, Rockwell Medical, and Zensun. Dr Zile has received research funding from Novartis; and has served as a consultant for Novartis, Abbott, Boston Scientific, CVRx, EBR, Endotronix, Ironwood, Merck, Medtronic, and Myokardia V Wave. Dr Pfeffer has received research grant support (via institution) from Lexicon and Novartis; has been a consultant to Alnylam Pharmaceuticals, Apnimed, AstraZeneca, Boehringer Ingelheim, Eli Lilly Alliance, DalCor, Intellia, National Heart, Lung, and Blood Institute CONNECTs (Master Protocol Committee), Novartis, and Novo Nordisk; and holds equity in DalCor. Dr McMurray has received payments through Glasgow University from work on clinical trials, consulting, and other activities from Amgen, AstraZeneca, Bayer, Cardurion, Cytokinetics, GlaxoSmithKline, KBP Biosciences, and Novartis; has received personal consultancy fees from Alnylam Pharma, Bayer, BMS, George Clinical PTY, Ionis Pharma, Novartis, Regeneron Pharma, and River 2 Renal Corporation; has received personal lecture fees from Abbott, Alkem Metabolics, AstraZeneca, Blue Ocean Scientific Solutions, Boehringer Ingelheim, Canadian Medical and Surgical Knowledge, Emcure Pharma, Eris Lifesciences, European Academy of Continuing Medical Education, Hikma Pharmaceuticals, Imagica health, Intas Pharma, JB Chemicals and Pharma, Lupin Pharma, Medscape or Heart.Org, ProAdWise Communications, Radcliffe Cardiology, Sun Pharma, The Corpus, Translation Research Group, and Translational Medicine Academy; and is a director of Global Clinical Trial Partners. Dr Solomon has received research grants from Actelion, Alnylam, Amgen, AstraZeneca, Bellerophon, Bayer, Bristol Myers Squibb, Celladon, Cytokinetics, Eidos, Gilead, GlaxoSmithKline, Ionis, Lilly, Mesoblast, MyoKardia, National Institutes of Health/NHLBI, Neurotronik, Novartis, Novo Nordisk, Respicardia, Sanofi Pasteur, Theracos, and US2.AI; and has consulted for Abbott, Action, Akros, Alnylam, Amgen, Arena, AstraZeneca, Bayer, Boehringer Ingelheim, Bristol Myers Squibb, Cardior, Cardurion, Corvia, Cytokinetics, Daiichi-Sankyo, GlaxoSmithKline, Lilly, Merck, Myokardia, Novartis, Roche, Theracos, Quantum Genomics, Cardurion, Janssen, Cardiac Dimensions, Tenaya, Sanofi-Pasteur, Dinaqor, Tremeau, CellPro-Thera, Moderna, American Regent, and Sarepta. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2025 The Authors. Published by Elsevier Inc. All rights reserved.)