Associations between prediabetes, type 2 diabetes and incident atrial fibrillation in patients with hypertension: Results from the Swedish Primary Care Cardiovascular Database

To study associations between prediabetes, type 2 diabetes (T2D) and insulin resistance with incident atrial fibrillation (AF) in patients with hypertension. Patients with hypertension but no AF between 2006 and 2010 were identified in the Swedish Primary Care Cardiovascular Database. Patients with type 1 diabetes or pre-existing cardiovascular disease were excluded. Patients were categorized into normoglycemia, prediabetes or T2D and followed until 2023 or incident AF. Insulin resistance was assessed using triglyceride–glucose (TyG) index and TyG–BMI index. Associations with incident AF and mortality were evaluated using multivariable models. Among 15 715 patients (64 ± 11 years, 55% women), 60% were normoglycemic, 17% had prediabetes and 23% T2D. During a median follow-up of 14.7 years, AF occurred in 18%, 21% and 20%, respectively. Neither prediabetes (HR 0.99, 95% CI 0.87-1.13) nor T2D (HR 1.00, 95% CI 0.89-1.11) was associated with incident AF compared with normoglycemia. In contrast, the TyG index demonstrated a U-shaped association with incident AF, whereas the TyG-BMI index showed a positive association. Both prediabetes and T2D were associated with increased all-cause mortality (HR 1.17, 95% CI 1.06-1.30 and HR 1.62, 95% CI 1.50-1.75, respectively). Prediabetes and T2D were not independently associated with AF in hypertensive patients. Our findings suggest a potential role for BMI and insulin resistance in AF risk, independent of glycemic category, warranting further prospective investigation.