Aims: Patients with coronary artery disease (CAD) and patients with peripheral artery disease (PAD) are at risk for major adverse cardiovascular events (MACE) and major adverse limb events (MALE). There are limited data regarding dietary patterns and the risk of recurrent MACE and MALE in CAD and PAD patients. We aimed to identify dietary patterns associated with MACE and MALE in patients with CAD and/or PAD., Methods and Results: We analysed data collected from patients enrolled into the Cardiovascular Outcomes for People Using Anticoagulation Strategies (COMPASS) trial, in which diet was assessed by a short food frequency questionnaire (FFQ) at baseline. Two dietary pattern scores, the modified Alternate Healthy Eating Index (mAHEI) and Mediterranean Diet Score (mMDS), were calculated. We tested the association between mAHEI and mMDS and the incidence of MACE and/or MALE. The mean mAHEI score was 23.0 ± 7.7 (out of 70) overall and was similar comparing CAD and PAD patients. The incidence of MACE or MALE was 6.3% in the lowest diet quality quartile (as assessed by mAHEI) compared with 4.2% in the highest quartile over 30 months. In the fully adjusted model, the hazard ratio of a low diet quality (Quartile 1) compared with the highest (Quartile 4) for MACE or MALE was 1.27 (95% CI: 1.08-1.49; P = 0.004, Q1 vs. Q4). This excess hazard was primarily driven by higher MACE in both the CAD and PAD cohorts., Conclusions: Poor diet quality as assessed by the mAHEI is independently associated with a higher risk of recurrent MACE and MALE in patients with chronic CAD and/or PAD., Competing Interests: Conflict of interest: D.W. has received honoraria from Amgen Canada, HLS Therapeutics Inc., and Sanofi–Aventis Canada. M.D. has no disclosures. R.d.S. has received grants from the Canadian Foundation for Dietetic Research, the Canadian Institutes of Health Research, the Hamilton Health Sciences Corporation, and the Population Health Research Institute; receiving personal and/or travel fees from Health Canada, McMaster Children’s Hospital, the University of Toronto, and the World Health Organization; serving as a member of the Nutrition Science Advisory Committee to Health Canada and the Scientific Advisory Committee on Nutrition Subgroup on the Framework for the Evaluation of Evidence (Public Health England); serving as an external resource person to the World Health Organization Nutrition Guidelines Advisory Group on trans fats, saturated fats, and polyunsaturated fats; and serving as an independent director of the Helderleigh Foundation outside the submitted work. C.R. has no disclosures. J.E. reports grants and personal fees from Bayer, Boehringer Ingelheim, Bristol–Myers Squibb/Pfizer, and Daiichi Sankyo, during the conduct of the study, and grants and personal fees from Bayer, Boehringer Ingelheim, Bristol–Myers Squibb/Pfizer, Daiichi Sankyo, Janssen, Astra Zeneca, Eli Lilly, Glaxo Smith Kline, and Sanofi Aventis, outside the submitted work. J.B. has no disclosures. A.M. reports personal fees from Novartis, Bayer, Fresenius, and Cardiorentis. D.B. discloses the following relationships—Advisory Board: AngioWave, Bayer, Boehringer Ingelheim, Cardax, CellProthera, Cereno Scientific, Elsevier Practice Update Cardiology, Janssen, Level Ex, Medscape Cardiology, Merck, MyoKardia, NirvaMed, Novo Nordisk, PhaseBio, PLx Pharma, Regado Biosciences, and Stasys; Board of Directors: AngioWave (stock options), Boston VA Research Institute, Bristol Myers Squibb (stock options), DRS.LINQ (stock options), Society of Cardiovascular Patient Care, and TobeSoft; Chair: Inaugural Chair, American Heart Association Quality Oversight Committee; data monitoring committees: Acesion Pharma, Assistance Publique–Hôpitaux de Paris, Baim Institute for Clinical Research (formerly Harvard Clinical Research Institute, for the PORTICO trial, funded by St. Jude Medical, now Abbott), Boston Scientific (Chair, PEITHO trial), Cleveland Clinic (including for the ExCEED trial, funded by Edwards), Contego Medical (Chair, PERFORMANCE 2), Duke Clinical Research Institute, Mayo Clinic, Mount Sinai School of Medicine (for the ENVISAGE trial, funded by Daiichi Sankyo; for the ABILITY-DM trial, funded by Concept Medical), Novartis, Population Health Research Institute, and Rutgers University (for the NIH-funded MINT Trial); honoraria: American College of Cardiology (Senior Associate Editor, Clinical Trials and News, ACC.org; Chair, ACC Accreditation Oversight Committee), Arnold and Porter law firm (work related to Sanofi/Bristol–Myers Squibb clopidogrel litigation), 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), Canadian Medical and Surgical Knowledge Translation Research Group (clinical trial steering committees), Cowen and Company, 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), K2P (Co-Chair, interdisciplinary curriculum), Level Ex, Medtelligence/ReachMD (CME steering committees), MJH Life Sciences, Oakstone CME (Course Director, Comprehensive Review of Interventional Cardiology), Piper Sandler, 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), and Wiley (steering committee); other: Clinical Cardiology (Deputy Editor), NCDR–ACTION Registry Steering Committee (Chair), VA CART Research and Publications Committee (Chair); research funding: Abbott, Acesion Pharma, Afimmune, Aker BioMarine, Amarin, Amgen, AstraZeneca, Bayer, Beren, Boehringer Ingelheim, Boston Scientific, Bristol–Myers Squibb, Cardax, CellProthera, Cereno Scientific, Chiesi, CSL Behring, Eisai, Ethicon, Faraday Pharmaceuticals, Ferring Pharmaceuticals, Forest Laboratories, Fractyl, Garmin, HLS Therapeutics, Idorsia, Ironwood, Ischemix, Janssen, Javelin, Lexicon, Lilly, Medtronic, Merck, Moderna, MyoKardia, NirvaMed, Novartis, Novo Nordisk, Owkin, Pfizer, PhaseBio, PLx Pharma, Recardio, Regeneron, Reid Hoffman Foundation, Roche, Sanofi, Stasys, Synaptic, The Medicines Company, 89Bio; royalties: Elsevier (Editor, Braunwald’s Heart Disease); Site Co-Investigator: Abbott, Biotronik, Boston Scientific, CSI, Endotronix, St. Jude Medical (now Abbott), Philips, Svelte; Trustee: American College of Cardiology; unfunded research: FlowCo, Takeda. S.Y. has received research grants, honoraria, and travel expenses for lectures from Bayer, Boehringer Ingelheim, Bristol–Myers Squibb, and AstraZeneca. S.A. has received speaking honoraria and consulting fees from Bayer and speaking fees from Janssen., (© 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.)