Atrial fibrillation and its association with type 2 diabetes and hypertension in a Swedish community

Aim: To explore the prevalence of atrial fibrillation in patients with hypertension and type 2 diabetes and to identify possible mechanisms for the development of atrial fibrillation. Methods: A community-based, cross-sectional observational study was conducted in the primary health care in Skara, Sweden, and 1739 subjects (798 men, 941 women) were surveyed. Patients were categorized as those with hypertension only (n = 597); those with both hypertension and type 2 diabetes (n = 171), and those with type 2 diabetes only (n = 147). In the reference population, 824 normotensive subjects without diabetes were identified and used as controls. Participants were examined for cardiovascular risk factors including fasting blood glucose, serum insulin, blood pressure, lipids and anthropometric measures. Resting electrocardiogram (ECG) was recorded and Minnesota-coded. Insulin resistance was measured by the homeostasis model assessment (HOMA). Results: Age-adjusted prevalence of atrial fibrillation was 2% in patients with hypertension only, 6% in patients with both hypertension and type 2 diabetes, 4% in patients with type 2 diabetes only and 2% in controls, respectively. Age and sex adjusted odds ratios (OR) (95% CI) were; hypertension 0.7 (0.30-1.5), combined hypertension and type 2 diabetes 3.3 (1.6-6.7), and type 2 diabetes 2.0 (0.9-4.7). The association with combined hypertension and type 2 diabetes remained significant when adjusted for cardiovascular disease (CVD) risk factors and body mass index (BMI), was attenuated with adjustment for ischemic ECG; 2.4 (1.1-5.0) and lost significance with adjustment for insulin resistance; 1.3 (0.5-3.1). Conclusions: Atrial fibrillation is associated with the combined occurrence of type 2 diabetes and hypertension. Insulin resistance may be a common underlying mechanism.