BACKGROUND Atrial fibrillation (AF) frequently coexists with diabetes mellitus (DM), leading to a worse prognosis if both are present. Steatotic liver disease (SLD) may also predispose to DM, but its impact among AF patients is unclear. We aimed to determine whether metabolic dysfunction-associated SLD (MASLD), MASLD with increased alcohol intake (MetALD), or alcohol-related liver disease (ALD) elevates DM risk in AF.

METHODS Non-diabetic individuals who developed AF between 2010 and 2018 from the Korean National Health Insurance Service database were included. Patients with a fatty liver index (FLI) < 30 were classified as non-SLD, whereas those with FLI ≥ 30 and at least one cardiometabolic risk factors were categorized as MASLD, MetALD, or ALD based on daily alcohol intake. Incident DM hazard ratios (HRs) were estimated with Cox regression models.

RESULTS Among 195,195 patients (mean age 64.4 ± 13.0 years, 57.5% male); 108,918 (55.8%) in non-SLD, 71,795 (36.8%) in MASLD, 7644 (3.9%) in MetALD, and 6838 (3.5%) in ALD, respectively. Over a mean follow-up of 6.0 ± 2.9 years, 25,632 (13.0%) developed DM. Compared with non-SLD, the adjusted HRs with 95% confidence intervals (CIs) for incident DM were 1.930 (1.879-1.983), 1.789 (1.682-1.904), and 1.932 (1.817-2.054) for MASLD, MetALD, and ALD, respectively. In the age 20-39 years group, adjusted HRs with 95% CIs were 5.844 (4.501-7.587), 5.354 (3.681-7.787), and 7.033 (4.660-10.615), respectively.

CONCLUSION SLD confers an increased risk of new-onset DM in AF patients, especially in younger adults. Implementing management strategies to prevent DM in AF patients with SLD might mitigate the risk of DM and its potential impact on AF-related outcomes.