Twenty trials were included (32,311 participants). All studies were randomised, 11 were double-blind placebo controlled, one was single-blind placebo controlled and eight were open-label.
Statins were effective in preventing atrial fibrillation (OR 0.59, 95% CI 0.45 to 0.76; 20 trials, Ι²=71%). Very similar results were seen after seven trials that did not have atrial fibrillation as a prespecified endpoint were excluded from the analysis.
Subgroup analyses found that statins were effective in primary prevention (OR 0.67, 95% CI 0.51 to 0.88; 14 trials, Ι²=66%) and secondary prevention (OR 0.40, 95% CI 0.20 to 0.83; six trials, Ι²=77%). Atorvastatin was the more effective treatment overall (OR 0.43, 95% CI 0.27 to 0.66; 11 trials, Ι²=65%) and for the subgroup of atorvastatin doses of 10 to 40mg/day (OR 0.29, 95% CI 0.19 to 0.45; eight trials, Ι²=23%).
There was some evidence of publication bias overall and for the atorvastatin studies.