CRAVE: Coffee does not trigger atrial arrhythmias

The first results of the CRAVE (The Coffee and Real-Time Atrial and Ventricular Ectopy) study bringing good news to all coffee drinkers around the world were presented during the virtual American Heart Association (AHA) scientific sessions in November 2021. Despite the fact that coffee is the most commonly consumed beverage in the world, the majority of previous coffee-related research has been observational and focused on its long-term effects rather than immediate consequences.

In the CRAVE study, one-hundred consenting adults were fitted with a continuously recording ECG device (iRhythm, San Francisco, CA), a wrist-worn Fitbit (San Francisco, CA), a continuous glucose monitor (Dexcom, San Diego, CA), and downloaded a smartphone mobile application to collect geolocation data (Eureka, UCSF). The study used an N-of-1 design. Participants consumed as much coffee as they wanted for 1 day and avoided all caffeine the next, alternating the assignment in 2-day blocks over 2 weeks. They used a smartphone app to receive daily coffee assignments and reminders. To assess adherence, participants were asked to press a button for every coffee drink and were queried daily regarding actual coffee consumption the previous day. Date-stamped receipts for coffee purchases were reimbursed, and smartphone geolocation was used to track coffee shop visits.

Participants were a mean 38 ± 13 years old, 51% were women.  Adherence assessments revealed compliance with randomization assignment by every metric employed (each p<0.01). In intention-to-treat (ITT) analyses, there was no evidence of a relationship between coffee consumption and daily PAC counts (RR, 1.09; 95% CI, 0.98 - 1.20; P = 0.10). In contrast, participants had an average of 54% more PVCs on days randomized to coffee by ITT (RR, 1.54; 95% CI, 1.19 - 2.00; P = .001) and, per protocol, those consuming more than 2 cups of coffee per day had a doubling of PVCs (RR, 2.20; 95% CI, 1.24 - 3.92; P = 0.007). No relationship was observed with coffee consumption and SVT episodes in ITT analyses (RR, 0.84; 95% CI, 0.69 - 1.03; P = 0.10). The same was true for T episodes, which were admittedly rare.

In ITT analyses that adjusted for day of the week, participants took an average of 1058 more steps on days they drank coffee (95% CI, 441 - 1675 steps; P = 0.001) but slept 36 fewer minutes (95% CI, 22 - 50 minutes; P < 0.001). No significant differences in glucose levels were observed.

The genetic analyses of caffeine metabolism-related single nucleotide polymorphisms revealed 2 significant interactions: fast coffee metabolizers had a heightened risk for PVCs and slow metabolizers experienced more sleep deprivation.


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