Background: Diabetic retinopathy (DR) is the leading cause of blindness in working-age patients. Although prior studies revealed hyperglycemia as an imperative marker of diabetic retinopathy risk, whether glycemic variability imposes an increased risk of retinopathy remains unclear. As retinopathy is often diagnosed at later stages, when the potential benefit of intervention is significantly attenuated, assessing glycemic variability as an added source when selecting diabetes patients for earlier referral for ophthalmological evaluation may assist in preventing disability. To evaluate this hypothesis, this study investigated the relationship between glycemic variability parameters and diabetic retinopathy using data from a local cohort of patients with type 2 diabetes.
Basic procedures. This study included cohort members aged 18 years and older who had undergone ophthalmological examinations, including retinography and visual acuity testing, and who had at least two glycemic hemoglobin measurements throughout their participation in the study. The Early Treatment Diabetic Retinopathy Study (ETDRS)criteria were used to classify diabetic retinopathy. Using validated methods, glycemic variability was calculated as the standard deviation and mean amplitude of glycemic excursions.
Main findings: In the studied included 238 patients, 22% of individuals with type 2 diabetes mellitus (T2DM) had DR. Each 1% increase in baseline HbA1c was related to a 44% greater risk of diabetic retinopathy (OR 1.44, 95% CI 1.190–1.754, p 0.001). A one-unit increase in the standard deviation of HbA1c was associated with a 74% increased risk of DR (OR 1.74, 95% CI 1.067–2.847; p 0.027).
Principal conclusions: Glycated hemoglobin variability, measured as the standard deviation of repeated measures, was independently related to diabetic retinopathy risk (Clinicaltrials.gov: NCT04949152).