Cases of Legal Blindness and Visual Impairment Avoided Using Ranibizumab for Diabetic Macular Edema in the United States

Abstract

Purpose: : To estimate the magnitude of legal blindness and visual impairment avoided with monthly ranibizumab treatment for center-involved diabetic macular edema (DME) with vision impairment among non-Hispanic white and Hispanic individuals in the United States (US).

Methods: : A model was constructed to simulate visual acuity outcomes over 2 years following diagnosis and treatment of DME patients ≥45 years of age for whom ranibizumab has been shown to be beneficial. Visual outcomes included legal blindness defined as visual acuity (VA) letter score ≤38 in the better-seeing eye (approximate Snellen equivalent 20/200 or worse) and visual impairment defined as VA letter score ≤68 in the better-seeing eye (approximate Snellen equivalent worse than 20/40). Incident cases of DME were estimated based on: the US population size in 2011, the prevalence of diagnosed diabetes, and the 1-year incidence rate of clinically significant DME with vision impairment. The fellow eye was assumed not to have DME requiring treatment at the time of incident DME but could develop incident DME within the 2 years. Only patients with health insurance were included. VA changes with and without ranibizumab were based on the RISE and RIDE clinical trials. Baseline VA of the treated cohort was assumed to be similar to baseline VA of patients enrolled in RISE and RIDE.

Results: : The model predicted 17,007 incident cases of DME with visual impairment in 2011. Excluding individuals who do not have health insurance, 15,627 were eligible for ranibizumab treatment. Without ranibizumab, 281 (95% confidence interval, 72 to 655) cases of legal blindness were expected over 2 years. Monthly ranibizumab treatment reduced the cases of legal blindness by 81% (77% to 84%) to 54 (14 to 127) cases, with 227 (59 to 531) cases avoided. Without ranibizumab, 4,055 (1,028 to 9,428) cases of visual impairment were predicted in 2 years. Monthly ranibizumab reduced the cases of vision impairment by 38% (35% to 40%) to 2,517 (640 to 5,838), with 1,538 (394 to 3,578) cases avoided.

Conclusions: : In this model, monthly ranibizumab substantially reduced legal blindness and visual impairment within 2 years after diagnosis and treatment of non-Hispanic white and Hispanic patients with DME involving the center of the macula with vision impairment.

Clinical Trial: : http://www.clinicaltrials.gov NCT00473330

Keywords: clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials • low vision • diabetic retinopathy