Factors Affecting a Short-Term Response to Anti-VEGF Therapy in Diabetic Macular Edema

Abstract

Diabetic macular edema (DME) is a common cause of visual impairment in patients with diabetes. Although intravitreal anti-vascular endothelial growth factor (VEGF) injections were efficacious in clinical trials, several patients exhibited a poor response. This study aimed to compare clinical features between patients who were susceptible to intravitreal anti-VEGF injections for DME and those who were not. A single-center, retrospective study of 102 such patients was conducted (123 eyes; mean ± standard deviation age, 63.4 ± 10.8 years; 57.8% males). Systemic and ocular data, assessed at baseline and after a month, were compared between good (>20% decrease in central macular thickness (CMT)) and poor (≤20% decrease in CMT) responders using the Mann-Whitney U test/Fisher's exact test. Eighty-one eyes (65.9%) were good responders. The glycosylated hemoglobin level was higher (p = 0.011) in poor (7.5% ± 0.94%) than in good (7.04% ± 1.19%) responders. The foveal avascular zone was larger (p = 0.0003) in poor (0.67 ± 0.33 μm²) than in good (0.47 ± 0.23 μm²) responders. The number of microaneurysms in the pericapillary network was higher (p = 0.0007) in poor (2.7 ± 2.2) than in good (1.4 ± 2.0) responders. Baseline glycemic control and macular ischemia may be associated with the short-term response to intravitreal anti-VEGF injections.

Keywords: aflibercept; anatomical response; diabetic macular edema; fluorescein angiography; optical coherence tomography; ranibizumab; systemic factors.

Figure 1

Diabetic macular edema (DME) morphology. (a) Representative optical coherence tomography images of four types of DME morphology; (b) representative fundus photography (left) and fluorescein angiography images of DME (middle and right). The area colored in green indicates the foveal avascular zone and the red arrows indicate microaneurysms in the pericapillary network.

Figure 2

(a) The correlation between foveal avascular zone (FAZ) size and the number of microaneurysms (MAs) in the pericapillary network (PCN) (r = 0.42, p < 0.0001); (b) the FAZ size in each diabetic macular edema type; (c) the number of MAs in the PCN in each diabetic macular edema type; (d) the FAZ size among CME eyes that were good and poor responders; (e) the number of MAs in the PCN among CME eyes that were good and poor responders. * p < 0.05, ** p < 0.01, *** p < 0.001. The error bars indicate standard deviation. CME, cystoid macular edema; SDRT, sponge-like diffuse retinal thickening; SRD, serous retinal detachment; FULL, combination of CME, SDRT, and SRD.