Aims: STRONG-HF showed that rapid up-titration of guideline-recommended medical therapy (GRMT), in a high intensity care (HIC) strategy, was associated with better outcomes compared with usual care. The aim of this study was to assess the role of N-terminal pro-B-type natriuretic peptide (NT-proBNP) at baseline and its changes early during up-titration., Methods and Results: A total of 1077 patients hospitalized for acute heart failure (HF) and with a >10% NT-proBNP decrease from screening (i.e. admission) to randomization (i.e. pre-discharge), were included. Patients in HIC were stratified by further NT-proBNP changes, from randomization to 1 week later, as decreased (≥30%), stable (<30% decrease to ≤10% increase), or increased (>10%). The primary endpoint was 180-day HF readmission or death. The effect of HIC vs. usual care was independent of baseline NT-proBNP. Patients in the HIC group with stable or increased NT-proBNP were older, with more severe acute HF and worse renal and liver function. Per protocol, patients with increased NT-proBNP received more diuretics and were up-titrated more slowly during the first weeks after discharge. However, by 6 months, they reached 70.4% optimal GRMT doses, compared with 80.3% for those with NT-proBNP decrease. As a result, the primary endpoint at 60 and 90 days occurred in 8.3% and 11.1% of patients with increased NT-proBNP vs. 2.2% and 4.0% in those with decreased NT-proBNP (P = 0.039 and P = 0.045, respectively). However, no difference in outcome was found at 180 days (13.5% vs. 13.2%; P = 0.93)., Conclusion: Among patients with acute HF enrolled in STRONG-HF, HIC reduced 180-day HF readmission or death regardless of baseline NT-proBNP. GRMT up-titration early post-discharge, utilizing increased NT-proBNP as guidance to increase diuretic therapy and reduce the GRMT up-titration rate, resulted in the same 180-day outcomes regardless of early post-discharge NT-proBNP change., Competing Interests: Conflict of interest: A.M. has received grants from Roche Diagnostics, Abbott Laboratories, 4TEEN4, and Windtree Therapeutics; honoraria for lectures from Roche Diagnostics, Bayer, and MSD; is a consultant for Corteria Pharmaceuticals, S-form Pharma, FIRE-1, Implicity, 4TEEN4, and Adrenomed; and is coinventor of a patent on combination therapy for patients having acute or persistent dyspnoea. G.C. is employee of Momentum Research, which has received grants for research from Abbott Laboratories, Amgen, Celyad, Cirius Therapeutics, Corteria Pharmaceuticals, Heart Initiative, Sanofi, Windtree Therapeutics, and XyloCor Therapeutics. .G.C. is director of Heart Initiative, a non-profit organization. B.D. is employee of Momentum Research, which has received grants for research from Abbott Laboratories, Amgen, Celyad, Cirius Therapeutics, Corteria Pharmaceuticals, Heart Initiative, Sanofi, Windtree Therapeutics, and XyloCor Therapeutics. B.D. is director of Heart Initiative, a non-profit organization. A.C.S. has received honoraria for lectures or consultancy from AstraZeneca, Novartis, Vifor, Bayer, Merck, Sanofi, Abbott, and Boehringer Ingelheim. M.M. has received personal fees from Amgen, Livanova, and Vifor Pharma as a member of executive committees of sponsored clinical trials and from AstraZeneca, Bayer, Boehringer Ingelheim, Edwards Lifesciences, and Roche Diagnostics for participation to advisory boards or for speaking at sponsored meetings. C.E. is employee of Momentum Research, which has received grants for research from Abbott Laboratories, Amgen, Celyad, Cirius Therapeutics, Corteria Pharmaceuticals, Heart Initiative, Sanofi, Windtree Therapeutics, and XyloCor Therapeutics. O.C. received grants from Servier. R.D. has received supporting fees for coordination of STRONG-HF trial activities. G.F. has received lecture fees or was a committee member for trials and registries sponsored by Bayer, Vifor, Boehringer Ingelheim, Medtronic, Servier, and Amgen. K.S. has received grants from Medtronic, Servier, and Amylam and honoraria from MSD, Novartis, and Sanofi. A.A.V. has received consultancy fees or research support from AstraZeneca, Bayer, BMS, Boehringer Ingelheim, Cytokinetics, Myocardia, Merck, Novartis, Novo Nordisk, and Roche Diagnostics. MN is employee of Momentum Research, which has received grants for research from Abbott Laboratories, Amgen, Celyad, Cirius Therapeutics, Corteria Pharmaceuticals, Heart Initiative, Sanofi, Windtree Therapeutics, and XyloCor Therapeutics. KT is employee of Momentum Research, which has received grants for research from Abbott Laboratories, Amgen, Celyad, Cirius Therapeutics, Corteria Pharmaceuticals, Heart Initiative, Sanofi, Windtree Therapeutics, and XyloCor Therapeutics. A.D. works for the Faculty of Medicine, Eduardo Mondlane University (Maputo, Mozambique), which received research grants from the Heart Initiative for their participation in this study. P.S.P. has received grants or research contracts from American Heart Association, Roche, Siemens, Ortho Diagnostics, Abbott, Beckman Coulter, and Siemens; consulting fees from Roche; honoraria from WebMD; and he has financial interest in The Heart Course. J.C. has received personal fees from Novartis, AstraZeneca, Boehringer Ingelheim, Roche Diagnostics, and Pfizer. C.S.P.L. is supported by a Clinician Scientist Award from the National Medical Research Council of Singapore; has received research support from Bayer and Roche Diagnostics; has served as consultant or on the Advisory Board/Steering Committee/Executive Committee for Actelion, Alleviant Medical, Allysta Pharma, Amgen, AnaCardio AB, Applied Therapeutics, AstraZeneca, Bayer, Boehringer Ingelheim, Boston Scientific, Cytokinetics, Darma Inc., EchoNous Inc, Eli Lilly, Impulse Dynamics, Intellia Therapeutics, Ionis Pharmaceutical, Janssen Research & Development LLC, Medscape/WebMD Global LLC, Merck, Novartis, Novo Nordisk, Prosciento Inc, Radcliffe Group Ltd., Redcardio Inc, ReCor Medical, Roche Diagnostics, Sanofi, Siemens Healthcare Diagnostics and Us2.ai; and serves as co-founder and non-executive director of Us2.ai. M.P. has received personal fees from Abbott Laboratories, AstraZeneca, Boehringer Ingelheim and Vifor Pharma. MA has received speaker fees from Abbott Vascular and Medtronic. M.B. is employee of Momentum Research, which has received grants for research from Abbott Laboratories, Amgen, Celyad, Cirius Therapeutics, Corteria Pharmaceuticals, Heart Initiative, Sanofi, Windtree Therapeutics, and XyloCor Therapeutics. The other authors have no conflicts to report., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)