Impact of intensive glycemic control on the incidence of atrial fibrillation and associated cardiovascular outcomes in patients with type 2 diabetes mellitus (from the Action to Control Cardiovascular Risk in Diabetes Study).

Atrial fibrillation (AF) is prevalent in patients with type 2 diabetes mellitus (DM) and is associated with markers of poor glycemic control; however, the impact of glycemic control on incident AF and outcomes is unknown. The aims of this study were to prospectively evaluate if intensive glycemic control in patients with DM affects incident AF and to evaluate morbidity and mortality in patients with DM and incident AF. A total of 10,082 patients with DM from the Action to Control Cardiovascular Risk in Diabetes (ACCORD) cohort were studied in a randomized, double-blind fashion. Participants were randomized to an intensive therapeutic strategy targeting a glycated hemoglobin level of <6.0% or a standard strategy targeting a glycated hemoglobin level of 7.0% to 7.9%. Incident AF occurred in 159 patients (1.58%) over the follow-up period, at a rate of 5.9 per 1,000 patient-years in the intensive-therapy group and a rate of 6.37 per 1,000 patient-years in the standard-therapy group (p = 0.52). In a multivariate model, predictors of incident AF were age, weight, diastolic blood pressure, heart rate, and heart failure history. Patients with DM and new-onset AF had a hazard ratio of 2.65 for all-cause mortality (95% confidence interval 1.8 to 3.86, p <0.0001), a hazard ratio of 2.1 for myocardial infarction (95% confidence interval 1.33 to 3.31, p = 0.0015), and a hazard ratio of 3.80 for the development of heart failure (95% confidence interval 2.48 to 5.84, p <0.0001). In conclusion, intensive glycemic control did not affect the rate of new-onset AF. Patients with DM and incident AF had an increased risk for morbidity and mortality compared with those without AF.