Diabetic eye disease: A UK Incidence and Prevalence Study

Title: Diabetic eye disease: A UK Incidence and Prevalence Study

Author: Rohini Mathur et al. (London School of Hygiene and Tropical Medicine), Publisher: RNIB

This research report investigates trends into the prevalence and incidence of diabetic retinopathy in the UK.

Background

Diabetic retinopathy is one of the leading causes of sight loss and blindness in the UK, particularly among working age people. In the UK, within 20 years of diagnosis, nearly all people with Type 1 and almost two thirds of people with Type 2 diabetes have some degree of retinopathy. Prior to this research, there were no UK-wide population-based measures of incidence and prevalence.

To enhance our understanding of diabetic retinopathy in the UK, RNIB commissioned the London School of Hygiene and Tropical Medicine to estimate the incidence and prevalence of diabetic retinopathy.

Aims

The aims of the research were to analyse a large patient database with millions of records and ascertain:

• the prevalence and incidence of diabetic retinopathy in the UK by sub group
• whether diabetic retinopathy is more or less common in specific groups of people; specifically whether incidence and prevalence varies with age, sex, geographical location, ethnicity and socio-economic status
• an estimated time it takes to develop sight loss following onset of diabetic retinopathy.

Key Findings

• In 2014, the prevalence of diabetic retinopathy was 54.6% in people with Type 1 diabetes and 30.0% in people with Type 2 diabetes.
• The overall prevalence of diabetic retinopathy has been increasing steadily over the last 10 years. The increase is likely to be related to increasing prevalence of Type 2 diabetes and potentially increased ascertainment through nationwide screening programs.
• Higher rates of deprivation and minority ethnic groups were found to be associated with a higher risk of severe diabetic retinopathy amongst patients with Type 2 diabetes, confirming findings from previous studies.
• The research shows evidence of significant regional disparities in the spread of the condition. It could be that these differences are related to variations in screening program delivery, and therefore diagnoses across the country.

Publications

Results from the study have been published as an article in the peer reviewed British Medical Journal.

Notes on version

There are a number of slight differences between this report and the British Medical Journal paper ‘Population trends in the 10-year incidence and prevalence of diabetic retinopathy in the UK: a cohort study in the Clinical Practice Research Datalink 2004–2014’.

These differences are as follows:

1.   The report includes information on the crude incidence and prevalence of diabetic retinopathy in key population subgroups. The paper presents age-standardized incidence and prevalences. These figures are standardized against the mid-2014 UK population estimates from the Office for National Statistics - and thus take account for the age structure of the UK population (Figure 1 and table 2 in the paper).

2.   Severe diabetic retinopathy in the report includes codes for severe pre-proliferative retinopathy. In the paper, severe retinopathy is defined as proliferative retinopathy - and thus the severe DR population is slightly smaller in the paper compared to the report.

3.   Risk of developing retinopathy is presented as crude hazard ratios in the report- stratified by gender, age, ethnic group, calendar year, geographical region, and deprivation. (Tables 13 and 14). In the paper, the risk of developing retinopathy is presented as an adjusted hazard ratio, which takes into account age, gender, ethnic group, deprivation, geographic region, and additionally, duration of diabetes) This is figure 2 in the paper.