Timing and Duration of Glucagon-like Peptide-1 Receptor Agonist Use and Risk of Nonarteritic Anterior Ischemic Optic Neuropathy

PurposeTo investigate the association between glucagon-like peptide-1 receptor agonist (GLP-1RA) use and nonarteritic anterior ischaemic optic neuropathy (NAION) in type 2 diabetes, examining treatment recency and cumulative duration. MethodsThis nationwide registry-based nested case-control study utilised Danish health registries (1996-2023). Among 201,776 metformin-treated adults initiating second-line antihyperglycaemic therapy, 123 incident NAION cases were matched to 4,920 controls by birth year and sex (incidence-density sampling). Conditional logistic regression estimated adjusted hazard rate ratios (HRs) for GLP-1RA exposure by recency (current 0-90 days; recent 91-365 days) and cumulative duration, adjusting for socioeconomic factors, hypertension, hypercholesterolaemia, sleep apnoea, and diabetes duration. ResultsGLP-1RA use occurred in 63/123 cases (51.2%) and 1,688/4,920 controls (34.3%). Ever use was associated with a higher NAION rate than other second-line therapies (HR 2.13, 95% CI 1.43-3.18). Current use was associated with elevated rates (HR 2.28, 95% CI 1.49-3.48), whereas the estimate for recent use was imprecise (HR 1.69, 95% CI 0.88-3.25). By cumulative duration, no clear evidence of an increase was seen within 0-[1/2] years (HR 0.80, 95% CI 0.32-2.05), and rates were highest at [1/2]-1 year (HR 3.63, 95% CI 2.06-6.40) and 1-1[1/2] years (HR 3.52, 95% CI 1.73-7.17). Findings were consistent after HbA1c adjustment and in a new-user analysis. ConclusionGLP-1RA use is associated with a higher NAION rate in type 2 diabetes. This association appears time-dependent, being most pronounced during current treatment and peaking after 6-18 months of cumulative exposure.