Patients with type 1 diabetes, especially women, may be at higher risk for atrial fibrillation than the general population, a prospective case-control study found.
Using Swedish diabetes and population registries, researchers matched individuals with type 1 diabetes each with five randomly chosen controls for age, sex, and county of residence. They followed 36,258 patients with type 1 diabetes for a median of 9.7 years and 179,980 controls for a median of 10.2 years and obtained information on atrial fibrillation diagnoses from a national patient registry. Results of the industry-funded trial were published online Aug. 21 by The Lancet Diabetes & Endocrinology.
Overall, 749 (2%) of those with type 1 diabetes and 2,882 (2%) controls were diagnosed with atrial fibrillation. There were significant differences in atrial fibrillation risk between those with and without diabetes. In men, patients with type 1 diabetes had an adjusted hazard ratio for atrial fibrillation of 1.13 (95% CI, 1.01 to 1.25; P=0.029), and in women, the adjusted hazard ratio was 1.50 (95% CI, 1.30 to 1.72; P<0.0001).
Risk of atrial fibrillation increased with worse glycemic control and renal complications. Among patients with type 1 diabetes and normoalbuminuria, researchers found no excess risk of atrial fibrillation in men who had an HbA1c less than 9.7% or in women who had an HbA1c less than 8.8%.
The authors noted limitations to the study, such as the difficulty of determining onset of atrial fibrillation and the possibility that patients with diabetes have more clinic visits than the general population and therefore may have a greater chance of being diagnosed.
“Given the relation of diabetes duration and diabetic complications with atrial fibrillation and its complications, atrial fibrillation could be viewed as yet another manifestation of end-organ damage in diabetes,” an accompanying commentary said. For now, risk management of cardiovascular disease should be similar for patients with type 1 and type 2 diabetes, the editorialists recommended.