Comparison of Digital and Film Grading of Diabetic Retinopathy Severity in the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications Study

Larry D. Hubbard
2011 Archives of Ophthalmology  
Objective: To compare diabetic retinopathy (DR) severity as evaluated by digital and film images in a long-term multicenter study, as the obsolescence of film forced the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications Study (DCCT/ EDIC) to transition to digital after 25 years. Methods: At 20 clinics from 2007 through 2009, 310 participants with type 1 diabetes with a broad range of DR were imaged, per the Early Treatment Diabetic Retinopathy
more » ... y (ETDRS) protocol, with both film and digital cameras. Severity of DR was assessed centrally from film and tonally standardized digital cameras. For retinopathy outcomes with greater than 10% prevalence, we had 85% or greater power to detect an agreement of 0.7 or lower from our target of 0.9. Results: Comparing DR severity, digital vs film yielded a weighted of 0.74 for eye level and 0.73 for patient level ("substantial"). Overall, digital grading did not systematically underestimate or overestimate severity (McNemar bias test, P = .14). For major DR outcomes (Ն3-step progression on the ETDRS scale and disease presence at ascending thresholds), digital vs film values ranged from 0.69 to 0.96 ("substantial" to "nearly perfect"). Agreement was 86% to 99%; sensitivity, 75% to 98%; and specificity, 72% to 99%. Major conclusions were similar with digital vs film gradings (odds reductions with intensive diabetes therapy for proliferative DR at EDIC years 14 to 16: 65.5% digital vs 64.3% film). Conclusion: Digital and film evaluations of DR were comparable for ETDRS severity levels, DCCT/EDIC design outcomes, and major study conclusions, indicating that switching media should not adversely affect ongoing studies.
doi:10.1001/archophthalmol.2011.136 pmid:21670338 fatcat:xagfyfxu4vfo7bayegowepmiha