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

Purpose:

The increasing diabetes prevalence and advent of new treatments for its major visual-threatening complications (diabetic macular edema [DME] and proliferative diabetic retinopathy [PDR]), which require frequent life-long follow-up, have increased hospital demands markedly. Subsequent delays in patient's evaluation and treatment are causing sight loss. Strategies to increase capacity are needed urgently. The retinopathy (EMERALD) study tested diagnostic accuracy, acceptability, and costs of a new health care pathway for people with previously treated DME or PDR.

Design:
Prospective, multicenter, case-referent, cross-sectional, diagnostic accuracy study undertaken in 13 hospitals in the United Kingdom.

Participants:
Adults with type 1 or 2 diabetes previously successfully treated DME or PDR who, at the time of enrollment, had active or inactive disease.

Methods:
A new health care pathway entailing multimodal imaging (spectral-domain OCT for DME, and 7-field Early Treatment Diabetic Retinopathy Study [ETDRS] and ultra-widefield [UWF] fundus images for PDR) interpreted by trained nonmedical staff (ophthalmic graders) to detect reactivation of disease was compared with the current standard care (face-to-face examination by ophthalmologists).

Main Outcome Measures:
Primary outcome: sensitivity of the new pathway. Secondary outcomes: specificity; agreement between pathways; costs; acceptability; proportions requiring subsequent ophthalmologist assessment, unable to undergo imaging, and with inadequate images or indeterminate findings.

Results:
The new pathway showed sensitivity of 97% (95% confidence interval [CI], 92%–99%) and specificity of 31% (95% CI, 23%–40%) to detect DME. For PDR, sensitivity and specificity using 7-field ETDRS images (85% [95% CI, 77%–91%] and 48% [95% CI, 41%–56%], respectively) or UWF images (83% [95% CI, 75%–89%] and 54% [95% CI, 46%–61%], respectively) were comparable. For detection of high-risk PDR, sensitivity and specificity were higher when using UWF images (87% [95% CI, 78%–93%] and 49% [95% CI, 42%–56%], respectively, for UWF versus 80% [95% CI, 69–88%] and 40% [95% CI, 34%–47%], respectively, for 7-field ETDRS images). Participants preferred ophthalmologists’ assessments; in their absence, they preferred immediate feedback by graders, maintaining periodic ophthalmologist evaluations. When compared with the current standard of care, the new pathway could save £1390 per 100 DME visits and between £461 and £1189 per 100 PDR visits.

Conclusions:
The new pathway has acceptable sensitivity and would release resources. Users’ suggestions should guide implementation.