Evaluation of a new model of care for people with complications of diabetic retinopathy: The EMERALD Study

Noemi Lois, Jonathan A Cook, Ariel Wang, Stephen Aldington, Hema Mistry, Mandy Maredza, Danny McAuley, Tariq Aslam, Clare Bailey, Victor Chong, Faruque Ganchi, Peter Scanlon, Sobha Sivaprasad, David H Steel, Caroline Styles, Augusto Azuara-Blanco, Lindsay Prior, Norman Waugh, EMERALD Study Group

Research output: Contribution to journalArticle


Objectives: The increasing diabetes prevalence and advent of new treatments for its majorvisual-threatening complications (diabetic macular edema [DME] and proliferative diabeticretinopathy [PDR]), which require frequent and life-long follow-up, have markedly increasedhospital demands. Resulting delays in the evaluation/treatment of patients are leading tosight loss. Strategies to increase capacity of medical retina clinics are urgently needed.EMERALD tested diagnostic accuracy, acceptability and costs of a new health care pathwayfor people with previously treated DME/PDR.Design: Prospective, multicentric, case-referent, cross-sectional, diagnostic accuracy study,undertaken in 13 hospitals in the United Kingdom.Participants: Adults with type 1 or 2 diabetes and previously successfully treated DME/PDRwho, at the time of enrolment, had active or inactive disease.Methods: A new health care pathway entailing multimodal imaging (spectral domain opticalcoherence tomography [SD-OCT] for DME, and 7-field Early Treatment DiabeticRetinopathy Study [ETDRS] and ultra-wide-field fundus images [UWF] for PDR) interpretedby trained non-medical staff (ophthalmic graders) to detect re-activation of disease wascompared with the current standard care (ophthalmologists face-to-face examination).Main outcome measures: Primary outcome: sensitivity of the new pathway. Secondaryoutcomes: specificity; agreement between pathways; costs; acceptability; proportionsrequiring subsequent ophthalmologist assessment, unable to undergo imaging, withinadequate images/indeterminate findings.Results: The new pathway had sensitivity of 97% (95% confidence interval [CI] 92-99%)and specificity of 31% (95% CI 23-40%) to detect DME. For PDR, sensitivity and specificityusing 7-field ETDRS (85%, 95% CI 77-91%; 48%; 95% CI 41-56%, respectively) or UWF(83%, 95% CI 75-89%; 54%; 95% CI 46-61%, respectively) were comparable. For detection 5of high risk PDR sensitivity and specificity were higher when using UWF images (87%, 95%CI 78-93%; 49% 95% CI 42-56%, respectively for UWF, versus 80%, 95% CI 69-88%; 40%CI 34-47%, respectively, for 7-field ETDRS). Participants preferred ophthalmologist’sassessments; in their absence, wished immediate feedback by graders, maintaining periodicophthalmologist evaluations. When compared with the current standard care, the newpathway could save £1,390/100 DME visits and between £461-£1,189/100 PDR visits.Conclusion: The new ophthalmic grader pathway has acceptable sensitivity and wouldrelease resources. Users’ suggestions should guide implementation. 
Original languageEnglish
Publication statusPublished - 29 Oct 2020

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