Clinical characteristics of diabetes and diabetic retinopathy in an ageing population - NICOLA study

Abstract

Purpose : To examine the prevalence diabetic retinopathy (DR) among people with diabetes from the Northern Ireland Cohort of the Longitudinal Study of Aging (NICOLA Study) participants.

Methods : The Northern Ireland Cohort of the Longitudinal Study of Aging (NICOLA Study) is a multidisciplinary longitudinal population-based study of ageing. Retinal imaging at the NICOLA study health assessment included stereo colour fundus photography (Canon CX-1, Tokyo, Japan), spectral domain optical coherence tomography (SD-OCT) ((HRA+OCT; Heidelberg Engineering, Heidelberg, Germany). These were graded by NetwORC UK Ophthalmic Reading Centre. Medical history including medication was obtained during a home interview. A blood sample was used to assess HbA1C and non-fasting glucose level. WHO criteria were used for interpretation of HBA1C to diagnose Diabetes Mellitus (DM) (6-6.4=impaired glucose tolerance,>6.5=DM). Descriptive statistics were used to describe the prevalence of DR.

Results : Of the 3616 participants that completed a health assessment, 196 were home health assessments, a further 27 participants refused retinal imaging. Imaging from 3393 participants were available for analysis. Mean age of the sample was 63.44 (sd. 9.013 range. 36-99). The prevalence of diabetes was analysed through multiple measures including HbA1C, self-report, medication use and blood glucose level. According to the WHO classification 327 participants had diabetes (11.8%) and 310 had impaired glucose regulation (11.1%). Of the 327 participants only 167 (51.1) reported that they had the condition in response to questions in both the home interview and at the health assessment.
DR prevalence for those with DM was 11.3% (n=37). The prevalence of maculopathy was 8.3% (n=12). The number of individuals that fall into the categories background retinopathy, pre-proliferative, stable proliferative and active proliferative were 26, 4, 5 and 2 respectively.

Conclusions : This is the largest epidemiological study to date examining the burden of DM or DR in Northern Ireland and one of a few worldwide that has included OCT grading of maculopathy. Findings from this study will have implications for professionals working in the diabetes and sight loss sectors. The relatively large number of participants with high HbA1c who did not appear to be aware they had the condition is of particular concern.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.