Background: There is a need for better noninvasive remote monitoring solutions that prevent hospitalizations through the early prediction and management of heart failure (HF). SurveillanCe and Alert-Based Multiparameter Monitoring to ReducE Worsening Heart Failure Events (SCALE-HF 1) evaluated the performance of a novel congestion index that alerts to fluid accumulation preceding HF events., Methods and Results: SCALE-HF 1 was a multicenter, prospective, observational study investigating HF event prediction using data from the cardiac scale. Participants with HF took measurements at home by standing barefoot on the scale for approximately 20 seconds each day. The congestion index was applied retrospectively, and an alert was generated when the index exceeded a fixed threshold established in prior studies. HF events were defined as unplanned administration of IV diuretics or admissions with a primary diagnosis of HF. Sensitivity was defined as the ratio of correctly identified HF events to the total number of HF events. We enrolled 329 participants (mean age 64 ± 14 years; 43% women; 32% Black; 56% with reduced ejection fraction) across 8 sites with 238 participant-years of follow-up and 69 usable HF events. The congestion index predicted 48 of the 69 HF events (70%) at 2.58 alerts per participant-year. In contrast, the standard weight rule (weight gain of >3 lb in 1 day or >5 lb in 7 days) predicted only 24 of the 69 HF events (35%) at 4.18 alerts per participant-year. The congestion index alerts had a significantly higher sensitivity (P < .01) at a lower alert rate than the standard weight rule., Conclusions: The congestion index alerts demonstrated sensitive prediction of HF events at a low alert rate, significantly exceeding the performance of weight-based monitoring., Gov Identifier: NCT04882449., Competing Interests: Disclosures Dr. Fudim was supported by the National Heart, Lung, and Blood Institute (NHLBI) (K23HL151744), the American Heart Association (20IPA35310955), the Doris Duke Foundation, Bayer, Bodyport, and Verily. He receives consulting fees from Abbott, Alio Health, Alleviant, Audicor, AxonTherapies, Bayer, Bodyguide, Bodyport, Boston Scientific, Cadence, Coridea, CVRx, Daxor, Deerfield Catalyst, Edwards LifeSciences, EKO, Feldschuh Foundation, Fire1, Gradient, Intershunt, Medtronic, NIMedical, NXT Biomedical, Pharmacosmos, PreHealth, ReCor, Shifamed, Splendo, Sumacor, SyMap, Verily, Vironix, Viscardia, and Zoll. Dr. Sauer reports consulting for Bodyport, Abbott, Amgen, Bayer, Medtronic, Edwards Lifesciences, Boston Scientific, Impulse Dynamics, Acorai, Story Health, 35Pharma, Regeneron, and General Prognostics. Dr. Sauer also reports significant research funding from Abbott, Bayer, CSL Vifor, Pfizer, Rivus, Story Health, General Prognostics, and Impulse Dynamics and serves on clinical trial steering committees for Rivus, Bayer, Boston Scientific, Biotronik, Abbott, Impulse Dynamics, Story Health, and General Prognostics. Dr. Sauer also owns stock in ISHI, a privately held digital health company, for his role as a senior advisor. Dr. Lopes reports research grants or contracts from Amgen, Bristol-Myers Squibb, GlaxoSmithKline, Medtronic, Pfizer, and Sanofi-Aventis; funding for educational activities or lectures from Pfizer, Daiichi Sankyo, and Novo Nordisk; and funding for consulting or other services from Bayer, Boehringer Ingelheim, Bristol-Myers Squibb, and Novo Nordisk. Dr. Ozonat is a current employee at Bodyport Inc. Sarah Smith and Corey Centen are founders and employees of Bodyport Inc. Dr. Pandit is a clinical advisor to Bodyport. Dr. DeVore reports research funding through his institution from the American Heart Association, Biofourmis, Bodyport, Cytokinetics, American Regent, Inc., the NHLBI, Novartis, and Story Health. He also provides consulting services for and/or receives honoraria from Abiomed, AstraZeneca, Cardionomic, InnaMed, LivaNova, Natera, Novartis, Procyrion, Story Health, Vifor, and Zoll. He has also received nonfinancial support from Abbott for educational and research activities., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)