Objective:
To determine the efficacy of statin treatment in atrial fibrillation (AF) prevention in women.

Design:
Cohort study using data obtained in the Heart and Estrogen/Progestin Replacement Study (HERS).

Setting:
Secondary analysis of a multicentre, randomised controlled clinical trial.

Patients:
2673 Postmenopausal women with coronary disease.

Main outcome measures:
AF prevalence at baseline and incident AF over a mean follow-up of 4.1 years.

Results:
88 Women with AF were identified: 29 at baseline and 59 during follow-up. Women with AF were significantly less likely to be taking a statin at study enrolment than those without AF (22% vs 37%, p=0.003). Baseline statin use was associated with a 65% lower odds of having AF at baseline after controlling for age, race, history of myocardial infarction or revascularisation and history of heart failure (odds ratio 0.35, 95% confidence interval (CI) 0.13 to 0.93, p=0.04). The risk of developing AF during the study among those free from AF at baseline, adjusted for the same covariates, was 55% less for those receiving statin treatment (hazard ratio 0.45, 95% CI 0.26 to 0.78, p=0.004).

Conclusions:
Statin treatment is associated with a lower prevalence and incidence of AF after adjustment for potential confounders in postmenopausal women with coronary disease (Fig 2).

 Figure 2: Incidence of atrial fibrillation at follow-up based on presence of predictors. Points display hazard ratios, with adjustment for potential confounders. Bars represent 95% confidence intervals. Age, 10-year increase in age; race, Causcasian compared with all others; MI/revasc, history of myocardial infarction or revascularisation. (Reprinted from Pellegrini CN, Vittinghoff E, Lin F, et al. Statin use is associated with lower risk of atrial fibrillation in women with coronary disease: the HERS trial. Heart. 2009;95:704-708, with permission from the BMJ Publishing Group, Ltd.)