CHADS₂ score, statin therapy, and risks of atrial fibrillation

Objective: Little is known about the effectiveness of statins on primary prevention of atrial fibrillation in elderly patients. This study aimed to evaluate the efficacy of statin treatment for atrial fibrillation prevention in elderly patients with hypertension, and to determine if comorbidity or CHADS₂ (Congestive heart failure, Hypertension, Age ≥75 years, Diabetes mellitus, prior Stroke or transient ischemic attack) score can predict the effectiveness of statin treatment. Methods: Patients aged ≥65 years with hypertension were identified from a National Health Insurance research database (a systemic sampling from 2000 to 2009 with a total of 1,000,000 subjects). Medical records of 27,002 patients were used in this study, in which 2400 (8.9%) were receiving statin therapy. Risk of new-onset atrial fibrillation in statin users and nonusers was analyzed. Results: During the 9-year follow-up period, 2241 patients experienced new-onset atrial fibrillation. Statin users were younger than nonusers (72.4 vs 73.4 years) but had a higher prevalence of ischemic heart disease, diabetes mellitus, stroke, and chronic renal disease. Overall, statin therapy reduced the risk of atrial fibrillation by 19% (adjusted hazard ratio 0.81; 95% confidence interval, 0.69-0.95; P =.009). Subgroup analysis showed that statin use was beneficial in patients with or without a particular comorbidity. The effectiveness of statins was significant in patients with CHADS₂ score ≥2 (adjusted hazard ratio 0.69; 95% confidence interval, 0.57-0.85; P <.001). However, statin therapy was not as beneficial in hypertensive patients without other cardiovascular comorbidities (CHADS ₂ score =1). Conclusion: Statin therapy in elderly patients with hypertension reduces the risk of new-onset atrial fibrillation. Statins are more beneficial in patients with CHADS₂ score ≥2 than in those with score of 1.