Two-year recall for people with no diabetic retinopathy: a multiethnic population-based retrospective cohort study using real-world data to quantify the effect
Authors: Olvera-Barrios Abraham , Rudnicka Alicja R , Anderson John , Bolter Louis , Chambers Ryan , Warwick Alasdair N , Welikala Roshan , Fajtl Jiri , Barman Sarah , Remagnino Paolo , Wu Yue , Lee Aaron , Chew Emily Y , Ferris Frederick L. , Hingorani Aroon D , Sofat Reecha , Egan Catherine , Tufail Adnan , Owen Christopher G 
Published: June 2023

AbstractBackground/AimsThe English Diabetic Eye Screening Programme (DESP) offers people living with diabetes (PLD) annual screening. Less frequent screening has been advocated among PLD without diabetic retinopathy (DR), but evidence for each ethnic group is limited. We examined the potential effect of biennial vs annual screening on the detection of sight-threatening diabetic retinopathy (STDR) and proliferative diabetic retinopathy (PDR) among PLD without DR from a large urban-multi-ethnic English DESP.MethodsPLD in North-East London DESP (Jan-2012 to Dec-2021) with no DR on two prior consecutive screening visits with up to eight years of follow-up were examined. Annual STDR and PDR incidence rates, overall, and by ethnicity were quantified. Delays in identification of STDR and PDR events had 2-year screening intervals been used were determined.FindingsAmong 82,782 PLD (37% white, 36% South Asian, and 16% black people), there were 1,788 incident STDR cases over mean 4.3 (SD 2.4) years (STDR rate 0.51, 95%CI 0.47-0.55 per 100-person-years). STDR incidence rates per 100-person-years by ethnicity were 0.55 (95% CI 0.48-0.62) for South Asian, 0.34 (0.29-0.40) for white, and 0.77 (0.65-0.90) for black people. Biennial screening would have delayed diagnosis by 1-year for 56.3% (1,007/1,788) with STDR and 43.6% (45/103) with PDR. Standardised cumulative rates of delayed STDR per-100,000 for each ethnic group were 1904 (95%CI 1683-2154) for black, 1276 (1153-1412), and 844 (745-955) for white people.InterpretationBiennial screening would have delayed detection of some STDR and PDR by one-year especially among those of black ethnic origin, leading to healthcare inequalities.Key messagesWhat is already known on this topic?The UK National Screening Committee currently recommends annual eye screening for diabetic retinopathy among people living with diabetes at high risk of sight loss, but biennial screening among those at low risk of sight loss.Ethnic differences in diabetes and the development of sight-threatening diabetes complications have been reported.The effect of biennial vs annual diabetic eye screening among different ethnic groups at low risk of complications has not been quantified in large multi-ethnic diabetic eye screening programmes in the UK.What this study adds?We provide incidence rates for the development of new sight-threatening diabetic retinopathy and proliferative diabetic retinopathy in a low-risk group, overall and by different ethnic and age groups, in this diverse sociodemographic population without previous diabetic retinopathy.Implementation of biennial screening in this population would have delayed referral to hospital eye services by a year in near half of those with sight-threatening diabetes (56%) and proliferative retinopathy (44%), but higher absolute rates of delay were observed among the youngest and oldest compared with middle aged and pre-retirement age groups, and those of black ethnic origin compared with other ethnic groups. Higher hazards of STDR were observed in younger people.While the absolute number delayed is small relative to the size of the overall cohort, age and ethnic inequalities in delayed identification of complications were apparent.How this study might affect research, practice or policy?National implementation of a 2-year diabetic eye screening interval for people with low-risk diabetic retinopathy grades does not affect all population sub-groups equally with respect to delays in the detection and referral of the most serious eye disease. Younger people and people of black and Asian ethnicities are affected more than other groups with potential effects on vision and treatment outcomes.