Long-term HbA1c Variability and Treatment Outcomes of Intravitreal Injection in Diabetic Macular Edema

Abstract

Purpose: To evaluate the association between long-term glycated hemoglobin A (HbA1c) variability and treatment outcomes of anti-vascular endothelial growth factor (VEGF) injection in diabetic macular edema patients. Methods: The medical records of 49 eyes (38 patients) that received anti-VEGF injection for diabetic macular edema were reviewed retrospectively. Best-corrected visual acuity (BCVA) and central macular thickness (CMT) before injection and at one month and six months after injection were analyzed. HbA1c variability (HbA1c coefficient of variation [CV]) was calculated using the HbA1c results from the year prior to (before) and the year after injection and compared with clinical results. Results: In the group with a low mean HbA1c level before injection, the group with lower HbA1c CV showed greater reduction in macular edema one month after injection (low HbA1c CV, 122.4 ± 123.2 μm versus high HbA1c CV, 5.2 ± 37.0 μm, p = 0.027). In the group with high mean HbA1c, there was no significant difference between HbA1c variability and clinical features. In a multivariate analysis, the factor related to the reduction of macular edema was initial CMT (one month adjusted hazard ratio (aHR) 0.5, p < 0.001; six months aHR 0.3, p = 0.023). The factor associated with visual gain was initial visual acuity (LogMAR) (one month aHR 0.4, p < 0.001; six months aHR 0.4, p < 0.001). The association between mean HbA1c or HbA1c variability and clinical outcome was not significant. Conclusions: Unlike initial CMT or BCVA, mean HbA1c and HbA1c variability were not significantly associated with clinical outcomes of anti-VEGF injection in diabetic macular edema patients.