Alcohol Increases Ischemic Stroke Risk in Newly Diagnosed Atrial Fibrillation

Among patients newly diagnosed with atrial fibrillation (AF), current alcohol consumption was associated with higher risk for ischemic stroke compared with patients who never drank alcohol or stopped drinking after their diagnosis, according to a population-based cohort study published in the European Heart Journal.

For the study, investigators analyzed patient data from the Korean National Health Insurance Service (KNHIS) and from the National Health Screening database linked to the KNHIS. The study included patients aged 20 years and older who were newly diagnosed with AF from January 1, 2010 through December 31, 2016 and had undergone a health examination within 2 years before and after their diagnosis.

Investigators separated patients into 3 groups of alcohol consumption based on patient-reported questionnaires during the 2 health examinations: nondrinkers; abstainers from alcohol after AF diagnosis; and current drinkers, including sustained drinkers and new drinkers after the AF diagnosis. Investigators collected data on the amount of alcohol consumption per week using patient questionnaires, and classified alcohol consumption as mild (0 to <105 g), moderate (105 to <210 g), and heavy (210 g or more).

The primary outcome was the incidence of ischemic stroke during the follow-up period. Investigators followed up with patients from the second health examination within 2 years after their AF diagnosis until the occurrence of ischemic stroke, death, or the end of the study period on December 31, 2017, whichever came first.

Of 97,869 patients newly diagnosed with AF included in the study, 51% were nondrinkers, 13% were abstainers, and 36% were current drinkers. The mean age was 61.3 years and 62.4% were men. During 310,926 person-years of follow-up, 3120 patients (10 per 1000 person-years) were diagnosed with incident ischemic stroke. At 5 years of follow-up, abstainers and nondrinkers were associated with a lower risk of ischemic stroke than current drinkers, with an incidence rate difference (after inverse probability of treatment weighting [IPTW]) of −2.03 (−3.25 to −0.82) for abstainers and −2.98 (−3.81 to −2.15) for nondrinkers per 1000 person-years; and incidence rate ratios (after IPTW) of 0.75 (0.70 to 0.81) for nondrinkers and 0.83 (0.74 to 0.93) for abstainers vs current drinkers.

Among the current drinkers, 58.8% were mild drinkers, 23.5% were moderate drinkers, and 17.8% were heavy drinkers at the second health examination. Previously heavy drinkers had a significantly higher risk of ischemic stroke compared with nondrinkers, even if they had stopped drinking after their AF diagnosis (adjusted hazard ratio [aHR], 1.433; 95% CI, 1.122-1.831).

All current drinkers had a significantly higher risk of ischemic stroke compared with nondrinkers, regardless of the amount of alcohol they consumed weekly, and there was a linear dose-response relationship between the amount of current alcohol intake and ischemic stroke risk.

In light of the substantial number of newly diagnosed AF patients who remained current drinkers in this study (36%), and given the research linking alcohol consumption with stroke incidence in AF, the study authors promoted including “lifestyle changes in the management of patients with AF,” with a focus on “proactive reduction and abstinence from alcohol consumption.”

The study was limited by its focus on ischemic stroke and not hemorrhagic stroke due to the way data were reported in the source databases.

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures. 

Reference

Lee SR, Choi EK, Jung JH, Han KD, Oh S, Lip GYH. Lower risk of stroke after alcohol abstinence in patients with incident atrial fibrillation: a nationwide population-based cohort study. Published online June 7, 2021. Eur Heart J. doi:10.1093/eurheartj/ehab315