Prevalence of referable, sight-threatening retinopathy in type 1 diabetes and its relationship to diabetes duration and systemic risk factors

PurposeThe purpose of the study was to provide contemporary estimates for diabetic retinopathy (DR) prevalence in a well-defined UK cohort of patients with type 1 diabetes (T1DM) and investigate potential risk factors for proliferative diabetic retinopathy (PDR) and diabetic maculopathy.Patients and MethodsFour hundred and sixty four T1DM patients in North Hampshire had T1DM duration, demographic and systemic risk factor data evaluated retrospectively alongside their DR status in 2010 using logistic regression analysis.ResultsOverall prevalence of any retinopathy, PDR, and maculopathy was 71.5%, 6.5%, and 10.8%, respectively. PDR and maculopathy prevalence were 0 and 0.7% for <10 years T1DM duration. PDR prevalence was 4%, 8%, and 16% for 10-19.9 years, 20-29.9, years and ≥30 years duration, respectively. Maculopathy prevalence was 15.6%, 18%, and 11% for 10-19.9 years, 20-29.9 years, and ≥30 years duration, respectively. In univariate analysis, PDR was associated with T1DM duration (odds ratio (OR) 1.07/year), age (OR 1.03/year), systolic blood pressure (OR 1.03/mmHg), and antihypertensive therapy (OR 10.63), while maculopathy was associated with duration (OR 1.03/year) and statin therapy (OR 2.83). In multivariate analysis, disease duration (OR 1.07/year) and antihypertensive therapy (OR 6.87) remained significantly associated with PDR, and maculopathy with statin therapy (OR 2.27).ConclusionThis study confirms T1DM duration is a strong risk factor for sight-threatening DR. Maculopathy and PDR prevalence within 10 years of T1DM diagnosis is very low. PDR prevalence at 10-20 years was 4% and then doubled for every 10-year interval thereafter up to 16% with ≥30 years duration. Antihypertensive therapy and statin therapy were strongly associated with PDR and maculopathy, respectively.