Sustained Moderate Visual Loss as a Predictive End Point for Visual Loss in Non-Proliferative Diabetic Retinopathy
Year of Publication
Girach, A; Aiello, L; Milton, R; Davis, M; Danis, R; Zhi, X; Sheetz, M; Vignati, L; PKC-DRS2 Study Group
Diabetic Retinopathy; Double-Blind Method; Enzyme Inhibitors; Indoles; Maleimides; Research Non-US Gov; ruboxistaurin; Treatment Outcome; Vision Disorders
PURPOSE: In PKC-DRS2, the efficacy of the oral PKC-beta inhibitor, ruboxistaurin 32 mg/day, was measured by the primary end point of sustained moderate visual loss (SMVL: a > or = 15 letter decrease from baseline on the ETDRS (Early Treatment Diabetic Retinopathy Study) chart sustained at least for the last 6 months of study participation). We now evaluate whether SMVL is more accurate than moderate visual loss (MVL: a single occurrence of a decrease from baseline of > or = 15 ETDRS letters) for predicting future visual loss. METHODS: Study eyes with moderately severe to very-severe non-proliferative diabetic retinopathy, best-corrected visual acuity of at least 45 letters on the ETDRS chart (approximately Snellen 20/125), and no prior pan retinal photocoagulation were evaluated in 506 patients (869 eyes) who completed 36 months of treatment. RESULTS: Sixty-five percentage (26/40) of study eyes with the onset of SMVL within 24 months of enrollment still had SMVL at study completion (36 months). In comparison, only 24% (30/126) with MVL within 24 months had SMVL at study completion. Analyses based on data from 6, 12, and 18 months of treatment were similar. CONCLUSIONS: SMVL is a more predictable measure of subsequent visual loss than is a single time point measure of MVL.