Risk of Dementia after initiation of GLP-1 RA versus long-acting insulin in patients with type 2 Diabetes mellitus

Background Recent studies suggest a decreased risk of dementia in patients treated with glucagon-like peptide-1 receptor agonist (GLP-1 RA). In this study, we compare the risk of dementia associated with GLP-1 RA versus long-acting insulin in adults aged over 50 years with type 2 diabetes (T2DM) using real-world administrative data from a large Taiwan cohort Design A population-based retrospective cohort study Setting We analyzed 10,783 propensity score-matched pairs of adults with T2DM who initiated either GLP-1 RA or long-acting insulin from Taiwan's National Health Insurance Research Database (2011-2021). Measurements Primary outcome was new-onset dementia; secondary outcomes included dementia requiring treatment and specific dementia subtypes (Alzheimer's disease, vascular dementia, and unspecified dementia). Hazard ratios (HRs) were estimated using Cox models. Results : Analysis of matched pairs identified 375 cases of newly diagnosed dementia. The incidence rate was 4.86 per 1,000 person-years in GLP-1 RA users versus 7.56 in insulin users. GLP-1 RA use was associated with significantly lower risk of overall dementia (HR 0.64, 95% CI 0.46-0.89, P=0.0072) and unspecified dementia (HR 0.41, 95% CI 0.24-0.68, P=0.0006), but not for Alzheimer's disease (HR 1.48, 95% CI 0.61-3.63, P=0.3867) or vascular dementia (HR 1.66, 95% CI 0.21-13.03, P=0.6324). Among GLP-1 RAs, both liraglutide (HR 0.40, 95% CI 0.20-0.80, P=0.0091) and dulaglutide (HR 0.42, 95% CI 0.19-0.92, P=0.0311) showed significant protective effects against unspecified dementia. Conclusions GLP-1 RA use was associated with lower dementia risk versus long-acting insulin in T2DM patients, especially with liraglutide and dulaglutide. As observational, causality requires confirmation from randomized controlled trials.