Independent Contribution of Diabetes to Increased Prevalence and Incidence of Atrial Fibrillation

OBJECTIVE Diabetes has long been recognized as a risk factor for atrial fibrillation, but its independent contribution to atrial fibrillation has not been fully evaluated. We sought to compare the prevalence and incidence of atrial fibrillation in age- and sex-matched patients with and without type 2 diabetes. RESEARCH DESIGN AND METHODS Using an observational cohort design, we selected 10,213 members of an HMO diabetes registry as of 1 January 1999 plus 7,159 patients who entered the registry by 31 December 2004 and matched them to patients without diabetes on year of birth and sex. All patients were followed until they died, left the health plan, or until 31 December 2008. We compared the baseline prevalence of atrial fibrillation and then followed patients without atrial fibrillation to compare atrial fibrillation incidence while controlling for known risk factors. RESULTS Atrial fibrillation prevalence was significantly greater among patients with diabetes (3.6 vs. 2.5%, P < 0.0001). Over a mean follow-up of 7.2 +/- 2.8 years, diabetic patients without atrial fibrillation at baseline developed atrial fibrillation at an age- and sex-adjusted rate of 9.1 per 1,000 person-years (95% CI 8.6-9.7) compared with a rate of 6.6 (6.2-7.1) among nondiabetic patients. After full adjustment for other risk factors, diabetes was associated with a 26% increased risk of atrial fibrillation among women (hazard ratio 1.26 [95% CI 1.08-1.46]), but diabetes was not a statistically significant factor among men (1.09 [0.96-1.24]). CONCLUSIONS In this population, diabetes was an independent determinant of atrial fibrillation prevalence but predicted incidence only among women. These findings have potential public health implications and emphasize the need for further investigation of the mechanistic links between diabetes and atrial fibrillation.