Prevalence of Diabetic Retinopathy in Screening-detected Diabetes mellitus: Results from the Gutenberg Health Study (GHS)

Abstract

Purpose: Type 2 diabetes mellitus (T2D) is characterised by a long asymptomatic period of hyperglycaemia. Therefore, complications such as diabetic retinopathy (DR) and diabetic maculopathy (DMac) may be present even at the time of diagnosis. The GHS is the first population-based study to collect data on the prevalence of DR and DMac in newly diagnosed (detected in screening) T2D.

Methods: GHS is a population-based, prospective, observational cohort study in midwestern Germany with a total of 15010 participants aged between 35 and 74. Participants underwent a standardized protocol including an ophthalmic examination and a complete general examination focused on cardiovascular parameters. The analyses of the fundus photographs were carried out at Moorfields Eye Hospital Reading Center by two certified graders according to the recommendations of the Early Treatment Diabetic Retinopathy Study. The sample was stratified by gender and decades of age. Percentages are given after reweighting according to the population structure of the recruitment area.

Results: Of 14,948 participants included into this analysis 1,377 had T2D (males 9.3% / females 6.2%). Of these, 25% (247/1377) had newly diagnosed T2D (screening-detected, defined by HbA1C ≥ 6.5%). The total prevalence of newly diagnosed T2D was 2.0% (males: 2.4% / females: 1.7%; < 65 years 1.6% / ≥ 65 years 3.7%). The fundus photographs of at least one eye of 283 participants with T2D were eligible for analysis. The overall prevalence of DR in screening detected T2D was 12.9%, whereas it was 12.0%, 0.6%, and 0.3% for mild or moderate non-proliferative, and for proliferative DR, respectively. No case of DMac was observed.<br /> The prevalence of DR in subjects younger than 65 years was 13.5% (13.0% for mild non-proliferative DR, 0% for moderate non-proliferative DR and 0.5% for proliferative DR), whereas it was 11.8% (10.1%, 1.7%, 0%) in those aged ≥ 65 years.

Conclusions: In this population-based study the prevalence of screening-detected T2D was low but one of eight of these newly diagnosed diabetics had evidence of diabetic retinopathy. In view of the high rate of microvascular complications at time of diagnosis, screening for diabetes is recommended. Community awareness and physician coordination should be emphasized to increase the eye examination rate in these individuals.