1,5-Anhydroglucitol and Time in Range as Complementary Markers for Diabetic Retinopathy in Type 2 Diabetes

The potential benefit of integrating continuous glucose monitoring (CGM) data with conventional glycaemic indicators in diabetes care remains to be determined. This study aimed to investigate the association between 1,5-anhydroglucitol (1,5-AG), a 1-2 weeks glycaemic marker with monitoring duration comparable to CGM, and diabetic retinopathy (DR).

The cross-sectional study included 5491 adults with type 2 diabetes. Participants were stratified by serum 1,5-AG levels (< 6.0 μg/mL, 6.0-10.0 μg/mL, and ≥ 10.0 μg/mL). Time in range (TIR) and glucose variability measures, including standard deviation (SD), coefficient of variation (CV), and mean amplitude of glycaemic excursions (MAGE), were calculated from CGM data.

Overall, the median serum 1,5-AG level was 3.4 (1.7-7.1) μg/mL, with a DR prevalence of 25.3% (n = 1387). The prevalence of DR increased with descending 1,5-AG levels (p for trend < 0.001). Compared to patients with 1,5-AG levels ≥ 10.0 μg/mL (reference), the adjusted odds ratio (OR) for DR was 1.64 (95% CI 1.35-2.01) in individuals with 1,5-AG < 6.0 μg/mL. In subgroup analyses stratified by TIR tertiles (< 58%, 58%-80%, and ≥ 80%), low 1,5-AG levels remained significantly associated with an elevated risk of DR in both the highest (OR = 1.44, 95% CI 1.09-1.91) and middle TIR tertiles (OR = 1.64, 95% CI 1.13-2.42). Regarding CGM-derived glucose variability metrics, while CV and SD were associated with DR in the overall population, none of MAGE, CV, or SD was significantly associated with DR in the highest TIR tertile.

Serum 1,5-AG is significantly associated with the prevalence of DR in type 2 diabetes. For patients with TIR ≥ 80%, 1,5-AG may reveal additional risk of DR.