HbA1c variability as an independent risk factor for diabetic retinopathy: results from a screening program

Aims To investigate the independent association between long-term glycemic variability, measured as the coefficient of variation (CV) of HbA1c, and the presence of diabetic retinopathy (DR) in a cohort of adults with diabetes within a systematic eye screening program. Methods This study screened 379 adults with type 1 and type 2 diabetes. Long-term glycemic variability was calculated as the CV of serial HbA 1c measurements. DR was assessed via dilated fundus photography. The association between HbA 1c CV and DR was analyzed using multivariable logistic regression adjusting for confounders. Results DR incidence of 12.4%, mostly mild non-proliferative. The median HbA 1c CV was 7.0% (53 mmol/mol). In unadjusted bivariate analysis, the incidence of mild DR was higher in the low- glycemic variability group (CV < 5%) compared to the high- glycemic variability group. However, the multivariable logistic regression analysis revealed that higher HbA 1c CV was independently associated with the presence of DR (β = 0.643, P = 0.042), alongside diabetes duration (P < 0.001) and age (P < 0.001). Conclusions In conclusion, in a cohort of individuals with both type 1 and type 2 diabetes and a low incidence of DR, long-term glycemic variability, estimated as HbA 1c CV, was independently associated with an increased risk of this complication.