The risk of dry and wet age-related macular degeneration (AMD) based on fasting glucose levels and disease duration of type 2 diabetes was investigated.

Using a health insurance claims database and the results of health examinations in South Korea, we conducted a retrospective, population-based cohort study of 2,103,604 adults ≥ 45 years of age who were AMD-free based on health checkups in 2009 and observed from January 1, 2011, to December 31, 2018. Glycemic status was classified into five groups: normal, impaired fasting glucose, new-onset diabetes (fasting glucose level ≥ 126 mg/dl but no diabetes diagnosis or diabetes medication), diabetes diagnosis < 5 years, and diabetes ≥ 5 years. According to the presence and absence of choroidal neovascularization, AMD was classified as wet AMD and dry AMD, respectively. Adjusted hazard ratios (HRs) of AMD occurrence were estimated in each category.

For dry AMD (n = 36,271, 1.72%), the HR was 1.192 (1.141–1.245) among subjects with diabetes < 5 years and 1.294 (1.242–1.349) among subjects with diabetes ≥ 5 years compared with subjects with normal glycemic status after adjusting for age, sex, body mass index, lifestyle, and medical history. For wet AMD (n = 12,912, 0.61%), the HR was 1.103 (1.011–1.203) among subjects with new-onset diabetes, 1.252 (1.167–1.344) among subjects with diabetes < 5 years, and 1.506 (1.413–1.605) among subjects with diabetes ≥ 5 years. The HR of AMD was significantly increased among participants ≤ 65 years old and those who did not have hypertension.

The incidence of dry and wet AMD increased among diabetes patients compared to the normal glycemic status group. These risks increased when the duration of diabetes was 5 years or more. The risk of wet AMD was increased among new-onset diabetes patients. These results suggest that high blood glucose levels without treatment might induce the vision-threatening condition of wet AMD, emphasizing the importance of early blood glucose management.