Does Eliminating Coffee Avoid Fibrillation? (DECAF)

A Randomized Controlled Trial to Assess Abstinence of Coffee Compared to Continued Consumption on Recurrent Atrial Fibrillation Following Cardioversion

Given both the increasing population impact of atrial fibrillation (AF) and the widespread consumption of coffee in society, determining an associated benefit or risk of coffee consumption on AF is of great clinical relevance. This study will evaluate the effect of randomly assigning participants undergoing cardioversion to coffee abstinence or coffee continuation over a 6 month period. This study will provide the first, randomized evaluation of coffee on AF outcomes and will provide important information on whether or not coffee has any effect on AF recurrence.

Study Overview

• Status: Completed
• Conditions: Atrial Fibrillation; Coffee
• Intervention / Treatment: Other: Avoid coffee; Other: Consume coffee

Detailed Description

The purpose of this study is to assess how abstinence of coffee compared to continued consumption affects recurrent atrial fibrillation (AF) following cardioversion. As one of the most consumed beverages in the world, whether coffee has any effect on health outcomes is of considerable interest to physicians, scientists, and individual consumers. While significant data exist on the potential impact of coffee on many cardiometabolic parameters, there is conflicting data on any role of coffee on AF.

Most studies so far have been observational in nature, limiting how much insight there is on the role of coffee on AF. This study proposes to directly compare AF outcomes for patients with AF that abstain from coffee versus those that continue coffee consumption.

A total of 200 AF patients undergoing cardioversion will be enrolled in this study (100 per arm), and followed for up to 6 months post cardioversion. Differences in AF recurrence and symptoms will be compared between the two groups.

• Study Type: Interventional
• Enrollment (Actual): 200
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Australia
  • Adelaide, Australia
    • Royal Adelaide Hospital
• Canada
  • Toronto, Canada
    • Sunnybrook Health Science Centre
• United States
  • California
    • San Francisco, California, United States, 94143
      • UCSF Parnassus

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 21 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Men or women ≥ 21 years of age
• Sustained AF or atrial flutter (provided patient has a history of AF)
• Planned/scheduled direct current electrical cardioversion
• Consumption greater than or equal to one cup of coffee per day sometime in the past 5 years
• Willing and able to comply with coffee abstinence or continuation for at least 6 months
• Life expectancy of at least 6 months
• Willing and able to return and comply with scheduled phone follow up visits
• Willing and able to provide written informed consent

Exclusion Criteria:

• Established allergy or adverse reaction to coffee
• Stated inability to comply with coffee abstinence or continuation
• AF ablation in preceding 3 months or planned in next 3 months
• Recent cardiothoracic surgery in preceding 3 months
• Pregnancy or desire to get pregnant within next 6 months.
• Current enrollment in an investigation or study of a cardiovascular device or investigational drug that would interfere with this study
• Any other criteria, which would make the patient unsuitable to participate in this study as determined by the Principal Investigator (e.g., an uncontrolled drug and/or alcohol addiction)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Avoid; Patients will undergo this intervention for up to 6 months, or whenever their AF or atrial flutter returns, whichever comes first.	Other: Avoid coffee; Abstain from coffee and other caffeinated products
Experimental: Consume; Patients will undergo this intervention for up to 6 months, or whenever their AF or atrial flutter returns, whichever comes first.	Other: Consume coffee; Drink coffee regularly (recommend at least 1 cup of caffeinated coffee or one shot of espresso per day)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of participants with first confirmed clinical recurrence of AF or atrial flutter, or device-detected recurrence lasting longer than 30 seconds, analyzed as a time-to-event outcome	The number and rate of AF or atrial flutter recurrence following cardioversion in the coffee abstinence group and the continued coffee group will be compared	6 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Adverse events	Any change in the number and rate of adverse events before censorship, including myocardial infarction, stroke or transient ischaemic attack, heart failure exacerbation, syncope, emergency department visit, hospitalization, and death, will be compared	6 months
Recurrent atrial flutter or AF separately	Any change in the number and rate of recurrent atrial flutter or AF separately as incident outcomes will be compared	6 months

Collaborators and Investigators

• Sponsor: University of California, San Francisco
• Investigators: Principal Investigator: Gregory M Marcus, MD, MAS, University of California, San Francisco; Principal Investigator: Christopher X Wong, MBBS, PhD, University of Adelaide; Principal Investigator: Christopher C Cheung, MD, MPH, Sunnybrook Health Sciences Centre

Publications and helpful links

General Publications

• Wong CX, Cheung CC, Montenegro G, Oo HH, Pena IJ, Tang JJ, Tu SJ, Wall G, Dewland TA, Moss JD, Gerstenfeld EP, Tseng ZH, Hsia HH, Lee RJ, Olgin JE, Vedantham V, Scheinman MM, Lee C, Sanders P, Marcus GM. Caffeinated Coffee Consumption or Abstinence to Reduce Atrial Fibrillation: The DECAF Randomized Clinical Trial. JAMA. 2025 Nov 9:e2521056. doi: 10.1001/jama.2025.21056. Online ahead of print.

Study record dates

Study Major Dates

• Study Start (Actual): October 20, 2021
• Primary Completion (Actual): June 5, 2025
• Study Completion (Actual): October 20, 2025

Study Registration Dates

• First Submitted: October 26, 2021
• First Submitted That Met QC Criteria: November 4, 2021
• First Posted (Actual): November 16, 2021

Study Record Updates

• Last Update Posted (Actual): November 26, 2025
• Last Update Submitted That Met QC Criteria: November 24, 2025
• Last Verified: November 1, 2025

More Information

Terms related to this study

• Keywords: atrial fibrillation; coffee; afib
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Pathologic Processes; Heart Diseases; Arrhythmias, Cardiac; Pathological Conditions, Signs and Symptoms; Atrial Fibrillation
• Other Study ID Numbers: 21-35115

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No