Dipeptidyl peptidase-4 inhibitors (DPP-4i) are one of the most widely used antihyperglycemic therapeutic classes in type 2 diabetes mellitus management. In April 2016 and August 2017, the US Food and Drug Administration (FDA) introduced sequential labelling requirements regarding heart failure risk related to DPP-4i. We explored longitudinal trends in prescription of DPP-4i before and after these FDA warnings in a multicenter health system. We identified all first-time prescriptions of DPP4i or their combinations across the Partners HealthCare system (Boston, MA) from October 2006 (FDA approval of first DPP-4i) to December 2018. Overall, 11,830 patients were newly prescribed DPP-4i during the study period. Primary care physicians (31.5%) were the most common prescribing specialty. Overall, 8.4%, 20.4%, and 11.6% had heart failure, atherosclerotic cardiovascular disease, and chronic kidney disease, respectively. Median number of background antihyperglycemic therapies was 2 [25th to 75th percentiles 1 to 2], commonly metformin (65.4%) and/or insulin (36.4%). The vast majority of prescriptions were sitagliptin (85.7%), followed by linagliptin (9.5%), saxagliptin (4.7%), and alogliptin (0.2%). Quarterly prescriptions rose gradually from 2006 to mid-2016, and have decreased consistently since then for each of the 4 DPP-4i. Declines in DPP-4i among high-risk groups and those initiated by endocrinologists were most pronounced. In conclusion, although DPP-4i remain a dominant oral antihyperglycemic therapy in clinical practice, new prescriptions have declined recently. These data may reflect relatively swift health system response to broad FDA safety communications regarding heart failure risk, which appeared to impact the entire DPP-4i class, including specific drugs that have not demonstrated any increased risk of heart failure., Competing Interests: Disclosures Dr. Vaduganathan is supported by the KL2/Catalyst Medical Research Investigator Training award from Harvard Catalyst (NIH/NCATS Award UL 1TR002541), serves on advisory boards for Amgen, AstraZeneca, Bayer AG, Baxter Healthcare, Boehringer Ingelheim, Cytokinetics, & Relypsa, and participates on clinical endpoint committees for studies sponsored by Novartis and the NIH. Dr. Singh reports no disclosures. Dr. Sharma has received support from Bayer-Canadian Cardiovascular Society, Alberta Innovates Health Solution, Bristol-Myers Squibb-Pfizer, Boehringer Ingelheim, Roche Diagnostics, and Takeda. Dr. Januzzi is supported in part by the Hutter Family Professorship; has received grant support from Abbott, Cleveland Heart Labs, Singulex, and Prevencio; has received consulting income from Roche Diagnostics, Critical Diagnostics, and Novartis; and has participated in clinical endpoint committees/data or safety monitoring boards for Novartis, Amgen, GE, Janssen, Pfizer, and Boehringer Ingelheim. Dr. Scirica reports research grants via Brigham and Women's Hospital from AstraZeneca, Eisai, Novartis, and Merck. Consulting fees from AstraZeneca, Biogen Idec, Boehringer Ingelheim, Covance, Dr. Reddy's Laboratory, Eisai, Elsevier Practice Update Cardiology, GlaxoSmithKline, Lexicon, Merck, NovoNordisk, Sanofi, St. Jude's Medical, and equity in Health [at] Scale. Dr. Butler has received research support from the NIH and European Union; and has been a consultant for Amgen, AstraZeneca, Bayer, Boehringer Ingelheim, Bristol-Myers Squibb, CVRx, Janssen, Luitpold Pharmaceuticals, Medtronic, Merck, Novartis, Relypsa, Vifor Pharma, and ZS Pharma. Dr. Zannad reports personal fees from Janssen Research & Development LLC and Bayer during the conduct of the study; personal fees from AstraZeneca, Boehringer Ingelheim, LivaNova, GE Healthcare, Amgen, Novartis, Quantum Genomics, Cardior Pharmaceuticals, CardioRenal, CVCT, Merck, CVRx, Vifor Fresenius Medical Care Renal Pharma, NovoNordisk, and MundiPharma outside the submitted work; fees for serving on a steering committee or a safety and data monitoring board from Actelion, Amgen, Bayer, Boehringer Ingelheim, Boston Scientific, CVRx, GE Healthcare, Janssen Research & Development LLC, Novartis, and ResMed; and consulting fees from AstraZeneca, Cardior Pharmaceuticals, CardioRenal, Quantum Genomics, and Vifor Fresenius Medical Care Renal Pharma. Dr. McGuire reports honoraria for trial leadership from Astra Zeneca, Sanofi Aventis, Janssen, Boehringer Ingelheim, Merck & Co, Pfizer, Novo Nordisk, Lexicon, Eisai, GlaxoSmithKline, Esperion, Lilly US; and honoraria for consulting for Astra Zeneca, Sanofi Aventis, Lilly US, Astra Zeneca, Boehringer Ingelheim, Merck & Co, Pfizer, Novo Nordisk, Metavant, Applied Therapeutics. Dr. Cannon reports research grants from (all >10K) Amgen, Boehringer-Ingelheim, Bristol-Myers Squibb (BMS), Daiichi Sankyo, Janssen, Merck; and consulting fees from Alnylam, Amarin, Amgen, Boehringer-Ingelheim, BMS, Eisai, Janssen, Kowa, Merck, Pfizer, Regeneron, and Sanofi. Dr. Bhatt discloses the following relationships - Advisory Board: Cardax, Cereno Scientific, Elsevier Practice Update Cardiology, Medscape Cardiology, PhaseBio, PLx Pharma, Regado Biosciences; Board of Directors: Boston VA Research Institute, Society of Cardiovascular Patient Care, TobeSoft; Chair: American Heart Association Quality Oversight Committee; Data Monitoring Committees: Baim Institute for Clinical Research (formerly Harvard Clinical Research Institute, for the PORTICO trial, funded by St. Jude Medical, now Abbott), Cleveland Clinic (including for the ExCEED trial, funded by Edwards), Duke Clinical Research Institute, Mayo Clinic, Mount Sinai School of Medicine (for the ENVISAGE trial, funded by Daiichi Sankyo), Population Health Research Institute; Honoraria: American College of Cardiology (Senior Associate Editor, Clinical Trials and News, ACC.org; Vice-Chair, ACC Accreditation Committee), Baim Institute for Clinical Research (formerly Harvard Clinical Research Institute; RE-DUAL PCI clinical trial steering committee funded by Boehringer Ingelheim; AEGIS-II executive committee funded by CSL Behring), Belvoir Publications (Editor in Chief, Harvard Heart Letter), Duke Clinical Research Institute (clinical trial steering committees, including for the PRONOUNCE trial, funded by Ferring Pharmaceuticals), HMP Global (Editor in Chief, Journal of Invasive Cardiology), Journal of the American College of Cardiology (Guest Editor; Associate Editor), Medtelligence/ReachMD (CME steering committees), MJH Life Sciences, Population Health Research Institute (for the COMPASS operations committee, publications committee, steering committee, and USA national co-leader, funded by Bayer), Slack Publications (Chief Medical Editor, Cardiology Today's Intervention), Society of Cardiovascular Patient Care (Secretary/Treasurer), WebMD (CME steering committees); Other: Clinical Cardiology (Deputy Editor), NCDR-ACTION Registry Steering Committee (Chair), VA CART Research and Publications Committee (Chair); Research Funding: Abbott, Afimmune, Amarin, Amgen, AstraZeneca, Bayer, Boehringer Ingelheim, Bristol-Myers Squibb, Cardax, Chiesi, CSL Behring, Eisai, Ethicon, Ferring Pharmaceuticals, Forest Laboratories, Fractyl, Idorsia, Ironwood, Ischemix, Lexicon, Lilly, Medtronic, Pfizer, PhaseBio, PLx Pharma, Regeneron, Roche, Sanofi Aventis, Synaptic, The Medicines Company; Royalties: Elsevier (Editor, Cardiovascular Intervention: A Companion to Braunwald's Heart Disease); Site Co-Investigator: Biotronik, Boston Scientific, CSI, St. Jude Medical (now Abbott), Svelte; Trustee: American College of Cardiology; Unfunded Research: FlowCo, Merck, Novo Nordisk, Takeda., (Copyright © 2020 Elsevier Inc. 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