AIM: To evaluate the effect of statins on reducing new-onset atrial fibrillation (AF) in a large real-world post-myocardial infarction (MI) population. Subsequently, to test if different statin doses, various types and compliance affected the incidence of new-onset AF post MI.

METHODS: All patients with first-time acute MI between 1997 and 2009 in Denmark and claimed prescriptions of statins after discharge were identified from the Danish nationwide administrative registers. Patients with a history of AF were excluded. Risk of new-onset AF according to statin use were analysed by multivariable time-dependent Cox regressions models adjusted for age, gender, year, concomitant medication, and comorbidity, and additionally in a propensity score-matched analysis.

RESULTS: A total of 89,703 patients with average follow up of 5.0 ± 3.5 years were included in this study. In the 56,044 patients receiving statins, 5698 (10%) had new-onset AF vs. 5010 (15%) in the 33,659 patients serving as controls. The adjusted Cox regression analysis showed significant reduction in new-onset AF (HR 0.83, 95% CI 0.80-0.87, p < 0.001) in statin users. Adjustment for propensity score yielded nearly identical results (HR 0.82, 95% CI 0.78-0.85, p < 0.001). Furthermore, patients compliant to statin treatment had significant reduction in new-onset AF (HR 0.84, 95% CI 0.80-0.87, p < 0.001). Finally, simvastatin and atorvastatin were significantly more effective than pravastatin (both p < 0.01) in reducing new-onset AF.

CONCLUSIONS: Statin therapy was significantly associated with less new-onset AF in a nationwide cohort of post-MI patients. Furthermore, statins showed a type-dependent effect in preventing new-onset AF. These results support the beneficial effect of statin therapy beyond lipid lowering in patients with MI and underline the importance of statin adherence and choice of statin type.