Influence of Glycosylated Hemoglobin on the Efficacy of Ranibizumab for Diabetic Macular Edema: A Post Hoc Analysis of the RIDE/RISE Trials

Abstract

To investigate the influence of glycosylated hemoglobin (HbA1c) on treatment outcomes in patients with diabetic macular edema (DME) receiving intravitreal ranibizumab. Post hoc analysis of 2 identical phase III clinical trials assessing the efficacy and safety of intravitreal ranibizumab in DME over 36 months (RIDE: NCT00473382/RISE: NCT00473330). A total of 483 adults with vision loss from DME treated with ranibizumab were included in this analysis from RIDE/RISE. Participants received monthly intravitreal ranibizumab (0.3 or 0.5 mg). Differences in visual and anatomic outcomes, and diabetic retinopathy (DR) severity score, between subgroups of patients with baseline HbA1c ≤7% versus HbA1c >7% at 36 months. There were 195 patients in RIDE/RISE who were treated with ranibizumab with a baseline HbA1c ≤7% and 288 patients with a baseline HbA1c >7% included in this analysis. The mean improvement in visual acuity (VA) at 36 months was +13 Early Treatment Diabetic Retinopathy Study (ETDRS) letters in patients with baseline HbA1c ≤7% compared with +11 ETDRS letters in the patients with a baseline HbA1c >7% (P = 0.17). After adjustment for baseline central foveal thickness (CFT) and duration of diabetes, the mean CFT reduction was -268 μm in patients with a baseline HbA1c ≤7% and -269 μm in patients with a baseline HbA1c >7% (P = 0.98; 95% confidence interval, -22.93 to 23.54). The proportion of patients with a ≥2-step improvement in DR severity score was 38% in patients with baseline HbA1c ≤7% compared with 41% in the patients with a baseline HbA1c >7% (P = 0.53). There was no correlation of baseline HbA1c with any visual or anatomic parameter. The improvement in VA, anatomic reduction of macular edema, and improvement in DR severity score with ranibizumab treatment seem to be independent of baseline HbA1c.