Sixteen studies were included (n=7,041), comprising six RCTs (n=3,546) and 10 observational studies (n=3,495).
Two RCTs scored 5 on the Jadad scale, one scored 4, one scored 3 and two scored 2 points. One RCT was a post-hoc analysis. Most of the observational studies met five or six of the seven quality criteria.
For RCTs, there was no significant difference in the development of atrial fibrillation between statins and control, RR 0.76 (95% CI: 0.55, 1.05; p=0.09). Significant heterogeneity was observed (p=0.0008, I2 =74%). The only sensitivity analyses to alter the main results was a significant decrease in atrial fibrillation when detected by Holter or continuous monitoring (RR 0.50, 95% CI: 0.93, 0.64; three studies, n=328; p<0.0000); no significant heterogeneity was observed (p=0.14, I2 =49%).
Observational studies showed that statins were associated with a statistically significant reduction in the risk of developing atrial fibrillation compared to control, RR 0.77 (95% CI: 0.70, 0.85; p<0.00001). The reduction in risk of atrial fibrillation was greatest in postoperative in-hospital studies, RR 0.61 (95% CI: 0.49, 0.76; three studies; p<0.0001). No significant heterogeneity was observed for either analysis.
Funnel plots for both RCTs and observational studies appeared asymmetrical suggesting the potential for publication bias.