Title: Effectiveness of Multimodal imaging for the Evaluation of Retinal oedema And new vesseLs in Diabetic retinopathy (EMERALD)
Funder: Health and Social Care Research and Development Division (HSC R&D) of Public Health Agency, Northern Ireland

Abstract: Title: “Effectiveness of Multimodal imaging for the Evaluation of Retinal Oedema And new vesseLs in Diabetic Retinopathy (EMERALD)” Background: Diabetic macular oedema (DMO) and proliferative diabetic retinopathy (PDR) are major causes of sight loss in UK. Following successful treatment, patients require close monitoring as reactivation may occur. With increasing prevalence of diabetes, new technologies and multiple monitoring visits the burden to the NHS is rising. Identifying efficient methods of surveillance is essential. Purpose: To evaluate performance, acceptability and cost-effectiveness of surveillance of patients with stable DMO/PDR using multimodal imaging and subsequent review by adequately trained staff and compare it with standard practice. Design: Prospective, case-referent cross-sectional diagnostic study. Setting: 10 HES in UK. Target population: People with previously successfully treated DMO/PDR. Inclusion criteria: Adults with type 1 or 2 diabetes previously successfully treated for DMO or PDR. Exclusion criteria: Unable to provide informed consent. Clinical pathways assessed (see Flow Chart): New pathway: Patients will undergo multimodal imaging with subsequent review by a trained photographer/imaging technician; if active disease or uncertain they would be referred to the ophthalmologist, if stable they will remain under this model of surveillance. Standard care: Ophthalmologist examining patients in clinic with imaging tests used in current practice. Primary outcome: Sensitivity of the new pathway to detect active DMO/PDR. Secondary outcomes: Specificity, positive/negative likelihood ratios, concordance, cost-effectiveness, patient acceptability, proportion of patients requiring subsequent clinical assessment by ophthalmologist, proportion of patients unable to undergo imaging and with images of inadequate quality for interpretation. Measures of costs & outcomes: The hypothesis to be tested is that the new pathway will be as sensitive as the standard but at less cost. If sensitivity of the new pathway is as good as the standard, the economic analysis will be cost-minimisation/cost-consequence analysis including assessment of ophthalmologist time released by the new pathway. Results in DMO and PDR will be assessed separately. If there was marginal loss in sensitivity, cost-effectiveness analysis will be carried out. Sample size: To be able to detect if the sensitivity of the new pathway was 10% away from the 80% target set would require 93 participants with each DMO/ PDR who have reactivated, with 2-sided 5% significance level and 90% power. The same number of participants who have not reactivated would enable to detect a specificity of 12% away from a 70% target. A 95% confidence interval for the new pathway sensitivity and specificity would have width of 8-14% depending on the observed level. Allowing for 10% missing/indeterminate results, 104 individuals who have re-activated and 104 who have not re-activated are required (208 each for DMO and PDR). Timetable: Setting up, training of photographers/imaging technicians: 6m; recruitment: 18m; data analysis: 4m; report writing: 2m.Total=30 months. Team’s expertise: Ophthalmologists experts in diabetic retinopathy (DR); experts on DR screening and training of graders; health economists; experts in health technology and qualitative assessments; methodologist with expertise in diagnostic studies; statistician; CTU; users.

Lay abstract: Diabetes is a major cause of blindness. There are two main reasons why diabetes can cause sight loss: by producing swelling (build up of fluid) of the macula, the area responsible for fine vision (called diabetic macular oedema); and by the growth of abnormal new blood vessels on the back of the eye which can bleed or pull the retina detaching it from the wall of the eye (called proliferative diabetic retinopathy). Patients with diabetic macular oedema are treated with laser or drugs injected into the eye which help to dry the macula; patients with proliferative diabetic retinopathy are treated with a different laser treatment to make the new vessels disappear. Once treated, patients are followed long-term as the fluid in diabetic macular oedema and new vessels in proliferative diabetic retinopathy could come back. Currently, in the NHS, eye doctors (ophthalmologists) assess patients at follow-up visits in hospital eye services. Often scans of the back of the eye (OCTs) are done to see if there is diabetic macular oedema. OCT is done by a photographer/imaging technician and results reviewed by the ophthalmologist looking after the patient in the clinic. In the follow-up of patients with proliferative diabetic retinopathy, an ophthalmologist most often examine the back of the eye (retina) of the patient to see if the disease is active or inactive, without getting photographs. Photographs could be taken and used to look for new blood vessels during follow-up but this is not usually done. Standard cameras are not able to photograph the whole retina with one photograph so several photographs are needed. In recent years new “wide-angle” cameras have been built and are available; these can photograph nearly all of retina with a single shot. This may be better for patients and may reduce the time required to obtain images. Given the increasing number of people with diabetes, the new treatments and the need for patients to be seen often, the workload related to diabetic macular oedema and proliferative diabetic retinopathy has increased making it difficult for the NHS to cope with the demand, specially related to shortage of ophthalmologists. This may lead to delays on patient’s reviews and treatments. If we could find new safe and acceptable ways to reduce the need for stable patients to be seen by ophthalmologists that would help patients and the NHS. This study is about how to follow-up patients with diabetic macular oedema and proliferative diabetic retinopathy that have been treated successfully and are stable. Can they be followed without seeing an ophthalmologist? We will find out whether a trained photographer/imaging technician can, not only obtain photographs but also decide whether the disease is active or inactive. If the disease is active (or if the photographer is not sure), patients would be referred to an ophthalmologist. If the disease is not active, the patient would return at a later date when the tests would be repeated. We will see if this new model of care is safe, accurate and efficient; we will compare it with the standard care (patient being examined by an ophthalmologist). We will find out if this new model of care is acceptable to patients. The key result will be whether the new model of care might miss patients with active disease needing treatment. We will also compare costs. The research team has expert clinicians (eye doctors), researchers and people with diabetes who will be actively involved in the project.

Research activity codes: 4.2 EVALUATION OF MARKERS AND TECHNOLOGIES
Health categories: EYE;METABOLIC AND ENDOCRINE