Response to anti-VEGF therapy in patients with diabetic macular edema is not affected by insulin use

Abstract

Purpose : Intravitreal anti-vascular endothelial growth factor (anti-VEGF) injections are the first-line therapy for the treatment of diabetic macular edema (DME). However, many patients with DME do not respond optimally. Insulin therapy is well established in diabetes care, but few studies have explored whether insulin use affects anti-VEGF treatment outcomes in patients with DME. This study sought to assess whether patients requiring exogenous insulin therapy responded functionally and anatomically differently to anti-VEGF therapy when compared to patients who were not treated with insulin.

Methods : This was a retrospective, single center study of 121 patients (189 eyes) who received anti-VEGF treatment for DME between 2014 and 2022 with at least 12 months of follow up. Eyes were classified by insulin used (n=155) or insulin naïve (n=34). Data was collected from the electronic medical record and optical coherence tomography machines over 24 months from DME diagnosis. Logarithm of minimal angle of resolution (logMAR) was used to analyze best corrected visual acuity (BCVA). Primary outcome measures were changes in BCVA, central foveal thickness (CFT), and macular volume (MV). Linear mixed models were used for data analysis.

Results : Baseline demographic and ocular characteristics were comparable between groups except baseline HbA1c (p=0.04) and age (p=0.002). After controlling for HbA1c and age, there was no significant difference in response to anti-VEGF therapy between groups. The average change in BCVA over 12 months was -0.067 (insulin used) vs. 0.041 logMAR (insulin naïve) (p=0.83) and over 24 months was -0.027 (insulin used) vs. 0.22 logMAR (insulin naïve) (p=0.18). The average change in CFT over 12 months was -73.5 (insulin used) vs. -80.2 μm (insulin naïve) (p=0.88) and over 24 months was -61.9 (insulin used) vs. -69.2 μm (insulin naïve) (p=0.87). The average change in MV over 12 months was -0.70 (insulin used) vs. -1.2 mm³ (insulin naïve) (p=0.40) and over 24 months was -0.52 (insulin used) vs. -0.75 mm³ (insulin naïve) (p=0.74).

Conclusions : These results suggest that insulin therapy does not affect functional and anatomic outcomes in patients receiving anti-VEGF for DME, supporting limited existing data. Further research is needed to understand factors that are affecting responsiveness to anti-VEGF therapy in patients with DME.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.