Common Belief to Quit Coffee Overturned: Group Drinking About 1 Cup a Day Had 39% Lower Risk of Atrial Fibrillation Recurrence

Contrary to the common belief that caffeinated coffee brings on arrhythmia, patients with atrial fibrillation (AF) who drank coffee had fewer recurrences, according to randomised trial results published in JAMA. The DECAF trial, led by researchers at the University of California San Francisco (UCSF), is the first randomised trial to directly assign coffee consumption and compare AF recurrence.

200 people compared over 6 months

At 5 hospitals in the United States, Canada and Australia, the researchers enrolled 200 patients (average age 69) with persistent atrial fibrillation or atrial flutter who were about to undergo electrical cardioversion. They were assigned 1:1 to a group that kept drinking coffee or a group that abstained from coffee and caffeine. Participants were people who usually drank coffee, and the design was open-label. Intake during follow-up was 7 cups a week versus 0 cups.

Over 6 months, recurrence of atrial fibrillation or flutter was 47% in the coffee group and 64% in the abstinence group, a 39% lower risk of recurrence in the coffee group (hazard ratio 0.61). Adverse events did not differ between the two groups. The researchers interpret this to mean there is weak basis for telling every patient with a coffee habit to quit.

However, the sample was small, participants knew their assignment, and only people who already drank coffee were included, so it is not grounds for newly recommending coffee to people who did not drink it. The results correspond to an intake of about 1 cup a day on average.