Relationship of Hemoglobin A1C and Outcomes of Treatment of Diabetic Macular Edema

Aims: To evaluate the relationship between Hemoglobin A1c (HbA1c) and visual and anatomical outcomes in eyes following treatment with intravitreal anti vascular endothelial growth factor (VEGF) agents and corticosteroids for diabetic macular edema (DME).

Study Design: Retrospective observational case series.

Place and Duration of Study: Michael E. DeBakey Veterans Affairs Medical Center in Houston, Texas between January 2012 and November 2014.

Methodology: Case series from a single institution of 194 eyes from 134 consecutive patients with DME in the absence of concurrent retinal disease treated with at least 3 intravitreal injections of bevacizumab, ranibizumab, or aflibercept with at least 6 months of follow-up.

Results: On multivariate analysis, initial HbA1c and initial BCVA were each associated to predict final visual outcome (p = 0.003 and p =0.001, respectively). Subgroup analysis demonstrated no statistical difference in improvement in mean BCVA (p=0.11) or mean CSMT (p=0.11) among patients whose hemoglobin A1c stayed stable, increased during the study or decreased during the study, however the mean number of injections required were respectively 6.5, 9.0 and 8.1 (p=0.02).

Conclusions: The visual outcome following intravitreal bevacizumab, ranibizumab, or aflibercept with or without adjunctive triamcinolone acetonide are weakly related to glycemic control at initiation of treatment. Patients with stable glycemic control during treatment require fewer injections to treat diabetic macular edema compared to patients with improvement or worsening in glycemic control.