Background/Purpose: Women with SLE have an increased risk of cardiovascular disease (CVD) and premature death. In the general population, moderate alcohol intake is associated with a cardioprotective effect. However, there is no data on the effect of alcohol intake in women with SLE, and it is unclear whether providers should advise SLE patients to avoid drinking. We examined the impact of alcohol consumption on risk of myocardial infarction (MI) and all-cause mortality in women with SLE in a general population setting. As a control lifestyle exposure, we also investigated the impact of current smoking on these endpoints.

Methods: We conducted a population-based cohort study of female patients with SLE using a medical record database representative of the general population of the UK. The exposure of interest was alcohol intake at cohort entry. Outcomes were incident cases of MI and all-cause mortality. We estimated hazard ratios (HR) of each outcome according to alcohol intake categories (i.e., 0, 1-14 [light-moderate drinking], and 15+ [heavy drinking] UK alcohol units/week [1 unit = 8 mg]). Multivariable Cox-proportional hazard models adjusted for age, smoking status, body mass index, duration of SLE, comorbidity index, and medication use.

Results: Among 2625 individuals with SLE (mean age 53.2 years), 1262 were non-drinkers, 1199 were light-moderate drinkers and 164 were heavy drinkers. Of each group by alcohol intake, 20.2%, 26.2% and 46.3% were current smokers, respectively. The mean duration of SLE at cohort entry was 9.3 years for non-drinkers, 8.8 years for light-moderate drinkers, and 8.2 years for heavy drinkers. Over mean follow up of 6.8 years, the overall mortality rates were 23.9, 12.8, and 19.5 deaths/1000 person-years (PY) for the non-drinkers, light-moderate drinkers, and heavy drinkers, respectively. Compared with non-drinkers, the multivariable HR of overall mortality for light-moderate alcohol intake was 0.69 (95% CI, 0.53-0.89). The multivariable HR of incident MI for light-moderate alcohol consumption was 0.53 (95% CI 0.28-1.00) relative to non-drinkers. In contrast, for current smokers, the multivariable HRs were 1.93 (95% CI 1.44-2.58) for mortality and 1.59 (95% CI 0.77-3.29) for incident MI.

Conclusion: These findings provide population-based evidence that women with SLE who consume light-moderate alcohol intake have lower incidence of MI and overall mortality when compared with non-drinkers. This protective effect from light-moderate alcohol use is seen in contrast with an increased risk of mortality associated with smoking, another lifestyle factor that correlates with alcohol intake including in this study population. For their cardioprotection and improved survival, women with SLE with light-moderate alcohol consumption may be advised that they do not need to refrain from alcohol intake, whereas smoking cessation should be strongly implemented.