Alcohol consumption and risk of cardiovascular outcomes and bleeding in patients with established atrial fibrillation

1. Low to moderate alcohol intake was not significantly associated with risk of stroke or other cardiovascular outcomes in patients with atrial fibrillation.

Evidence Rating Level: 2 (Good)

“Holiday heart syndrome” describes the association found between excessive alcohol intake and incidence of atrial arrhythmias. Even low amounts of regular alcohol intake have been associated with an increased risk of incident atrial fibrillation (AF). With alcohol consumption associated with an increased stroke risk in patients without AF and likely to increase bleed risk, many physicians recommend patients with AF, who are already at an elevated stroke risk and taking anticoagulants, to abstain from alcohol. However, the effects of alcohol intake on the risk of adverse events in patients with AF has been poorly studied. Results from two comparable prospective cohort studies conducted in Switzerland, BEAT-AF and Swiss-AF,  were combined, following a total of 3 852 patients with AF (mean age 71 + 10 years, 28% women, 85% on anticoagulants) for a median of 3.0 years. Data was collected from yearly follow-up visits and hospital records, and standardized case report forms were used to collect baseline personal characteristics. Analyses were conducted using time-updated multivariable-adjusted Cox proportional hazards models, which included adjustments first for age and sex, then for social factors, comorbidities, health behaviours, type of AF, as well as health perception. For the primary outcome, a composite endpoint of stroke and systemic embolism incidence, 136 strokes and systemic embolisms were reported. Patients were categorized into cohorts of nondrinkers, those who consumed >0 to <1 drinks/day, 1-<2 drinks/day, and >2 drinks/day. Drinking from any cohort was not significantly associated with a higher incidence of the primary outcome compared to nondrinkers (aHR: 0.87 (95% CI 0.55-1.37), 0.70 (95% CI 0.39-1.25), 0.96 (95% CI 0.56-1.6) respectively). Neither was any association found between alcohol consumption and incidence of bleeding. However, there was a nonlinear association between alcohol consumption and hospital admission for heart failure (p for quadratic trend=0.01) and myocardial infarction (p for quadratic trend=0.007). Those drinking 1 to <2 drinks/day were also nonlinearly associated with having the lowest risk of death (p for quadratic trend=0.001). Limitations of this study include its observational nature, the sample population was mostly white, that drinking was measured by self-reporting and may have been underreported, and the lack of heavy or binge drinkers in the study population, to which these results may not be as applicable. Overall, as there was no significant association found between low to moderate alcohol intake with stroke risk, other cardiovascular events, or increased bleed risk, these findings do not support any special recommendations for AF patients regarding alcohol consumption.

Click to read the study in CMAJ

Image: PD

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