DECAF: Caffeine Consumption Does Not Increase, May Improve Atrial Fibrillation Risk

Adult patients treated for atrial fibrillation (AF) who drank a cup of coffee daily exhibited 39% less risk of irregular heart rhythm episodes than those who avoided all caffeine, according to a new study.1

Data from the Does Eliminating Coffee Avoid Fibrillation (DECAF) trial was presented at the American Heart Association’s Scientific Sessions 2025 in New Orleans, Louisiana, by Christopher Wong, MBBS, MPH, PhD, professor of cardiology at the University of Adelaide and lead study author. DECAF was an investigator-initiated, prospective, open-label, international, multicenter, randomized clinical trial studying whether coffee is proarrhythmic.2

“An accurate understanding of any effect of caffeinated coffee on AF would be of great interest to patients and physicians alike,” Christopher Wong, MPH, MBBS, PhD, professor of cardiology at the University of Adelaide, and colleagues wrote. “Thus, the current randomized clinical trial compared caffeinated coffee consumption versus abstinence from coffee and caffeine in patients with AF.”2

Wong and colleagues included patients ≥21 years or older with sustained AF, planned direct current electrical cardioversion, coffee consumption of ≥1 cup per day sometime in the past 5 years, willingness to adhere to coffee abstinence or continuation, and life expectancy of ≥6 months. Patients who were not currently drinking coffee but met these criteria were eligible. Patients who had an established or adverse reaction to coffee, AF ablation or cardiothoracic surgery within 3 months, or pregnancy or desire to conceive within 6 months were excluded.2

Patients were followed up at 1, 3, and 6 months, at which point investigators determined caffeine consumption, medical history, medication inventory, recurrence of AF or atrial flutter, and adverse events. The primary endpoint of the study was clinically detected AF or atrial flutter recurrence lasting ≥30 seconds. Prespecified secondary endpoints included recurrence of AF and atrial flutter separately and adverse events including myocardial infarction, stroke, heart failure exacerbation, hospitalization, and death.2

A total of 1965 patients were initially screened, after which 1739 were excluded. An additional 427 were not willing to abstain from coffee or caffeine, and another 427 were unwilling to consume ≥1 cup per day or did not drink coffee. Another 26 patients were excluded due to unsuccessful cardioversion, leaving 200 patients to be randomly assigned in a 1:1 ratio to consumption of or abstinence from caffeinated coffee.2

At 6 month follow-up, investigators had noted a recurrence of AF or atrial flutter in 56% of patients (n = 111), including 47 patients in the consumption group and 64 in the abstinence group. In a primary intention-to-treat analysis, the time to recurrence was longer in the consumption group than the abstinence group, resulting in a 39% lower hazard ratio of recurrence with coffee consumption (HR, 0.61; 95% CI, 0.42-0.89; P = .01).2

Ultimately, investigators found a benefit for caffeinated coffee consumption which appeared consistent across most analyses of subgroup save for ablation history. However, investigators noted that this was not adjusted for multiplicity and encouraged cautious interpretation of these data.2

“It is reasonable for health care professionals to let their atrial fibrillation patients consider experimenting with naturally caffeinated substances that they may enjoy, such as caffeinated tea and coffee,” Gregory Marcus, MD, professor of medicine at the University of California and senior study author, said in a statement. “However, some people may still find that caffeine or caffeinated coffee triggers or worsens their atrial fibrillation.”1

References

1. Astle K. Cup of coffee a day may not be harmful for some adults with AFib and could lower episodes. Heart.org. November 9, 2025. Accessed November 9, 2025. https://newsroom.heart.org/news/cup-of-coffee-a-day-may-not-be-harmful-for-some-adults-with-afib-and-could-lower-episodes

2. Wong C, Cheung C, Montenegro G, et al. Caffeinated Coffee Consumption or Abstinence to Reduce Atrial Fibrillation: The DECAF Randomized Clinical Trial. JAMA. November 9, 2025. Accessed November 9, 2025. https://jamanetwork.com/journals/jama/fullarticle/2841253