What’s New? Brief Reports on Clinical Research
Kofi Cox (London, UK) Antoni Martínez-Rubio (Sabadell, Spain)
This article published by Voskoboinik A., et al. in the NEJM provides an interesting insight into the effects of alcohol consumption and abstinence on the recurrence of Atrial Fibrillation (AF). The article details a prospective, open label, randomised, controlled clinical trial performed across 6 hospitals in Australia and provides some convincing evidence for a decrease in AF recurrence and burden with reduced alcohol consumption.
Inclusion criteria for the trial included: being aged 18-85 years, having paroxysmal AF or symptomatic persistent AF with a rhythm control strategy and consuming more than 10 drinks/120g alcohol a week. Exclusion criteria included: Alcohol dependence or abuse, left ventricular systolic dysfunction, clinically significant non-cardiac illness or psychiatric disorders. The researchers screened a group of 697 patients from which 140 met the inclusion criteria. These 140 were randomly assigned from March 2016 – February 2018 to either the control group (70), who continued drinking as usual, and to an abstinence group (70), who were encouraged to cease their alcohol consumption for 6 months of the trial. Researchers defined 1 drink as a beverage containing 12g or pure alcohol; the beverage of choice was beer/wine for most of the participants. Time to recurrence and AF burden were determined across the 6 months using implantable devices such as pacemakers or implantable loop recorders or through the AliveCor mobile phone application. Patients also submitted ECG recordings twice a day (or more if symptomatic) or used 7-day Holder monitoring – data was then given in a blind fashion to 2 cardiologists to interpret with regard to the primary end points.
The authors present several important results. The abstinence group reduced their alcohol intake from 16.8±7.7 to 2.1±3.7 drinks per week over the 6 months, an 87.5% reduction (95% CI 12.7-16.7). The control group also slightly reduced their alcohol intake 16.4±6.9 to 13.2±6.5 drinks per week, a 19.5% reduction (95% CI 1.9-4.4).
With regard to the primary end points, the trial found that at 6 months a recurrence of AF of >30 seconds (after a 2-week blanking period) was documented in 37 patients (53%) in the abstinence group and in 51 patients (73%) in the control group. They also found that the time taken for the AF to recur was longer in the abstinence group with a hazard ratio of 0.55 (95% CI 0.36-0.84, P<0.005 by the log-rank test). The median percentage of time spent in AF (burden of AF) in the abstinence group was 0.5% (Interquartile range 0.0-3.0). In the control group the median percentage time spent in AF was much longer at 1.2% (Interquartile range 0.0-10.3). These results point to a marked reduction in both the primary end points, recurrence of AF and burden of AF, with the abstinence groups when compared to the control.
The trial had several secondary end points: AF related hospital admissions, weight change, scores on the modified European Heart Rhythm Association classification of AF at 6 months and some incomplete data regarding blood pressure, quality of life and mood of the trial participants at 6 months. Six participants were admitted to hospital in the abstinence group (9%) whereas the number of patients admitted to hospital in the drinking group for AF related reasons was 14 (20%). Regarding weight change, data was available for 84% of the abstinence group and 20% of the control at 6 months and after adjustment for baseline weight the abstinence group had a mean difference of -3.7 kg (95% CI, -4.8 to -2.5) when compared to the control. Concerning the European Heart Rhythm Association classification, data was available for 99% of the abstinence and 97% of the control. At 6 months only 10% of the abstinence reported moderate or severe symptoms of AF versus 32% in the control. The researchers recognise that their own data should be ‘interpreted with caution’ concerning Blood pressure, Quality-of-life scores and depression owing to missing data for 35% of the participants.
Limitations of the trial included: the use of different methods of arrythmia detection, the fact that only a small number of the abstinence group fully abstained from drinking, the bias of relying on the participants for reporting their own alcohol consumption, the lack of data for secondary outcomes and the fact that Sleep-disordered breathing may have been a confounding variable yet wasn’t assessed. They also recognised that differences in rhythm controlling therapy after the first recurrence of AF may have reduced the difference in AF burden between the groups.
The paper has some very significant implications for the link between AF and alcohol consumption. The researchers reference in their discussion 2 other papers quoting AF as the most common sustained arrhythmia1 and that most US adults drink alcohol2 and therefore a potentially very modifiable risk factor for AF, and the conditions secondary to it, would be reduced alcohol consumption.
As a conclusion, the manuscript data suggest that regular alcohol consumption is a potentially modifiable risk factor for atrial fibrillation. Thus, abstinence or a significant reduction in alcohol consumption resulted in a reduction of AF recurrence risk and AF burden.
Paper summarised:
Voskoboinik A, Kalman JM, De Silva A, Nicholls T, Costello B, Nanayakkara S, et al. Alcohol Abstinence in Drinkers with Atrial Fibrillation, N Engl J Med. [Internet]. 2020 Jan [cited 2020 Apr 8]; 382:20-28. Available from: https://www.nejm.org/doi/full/10.1056/NEJMoa1817591 doi: 10.1056/NEJMoa1817591
References
- Chugh SS, Havmoeller R, Narayanan K, Singh D, Rienstra M, Benjamin EJ, et al. Worldwide epidemiology of atrial fibrillation: a Global Burden of Disease 2010 Study. Circulation [Internet] 2014 Feb [cited 2020 Apr 8];129 (8) :837-847. doi: 10.1161/CIRCULATIONAHA.113.005119.
- Center for Behavioral Health Statistics and Quality. Behavioral health trends in the United States: results from the 2014 National Survey on Drug Use and Health. Rockville, MD: Substance Abuse and Mental Health Services Administration, 2015.