Epidemiology of moderately severe and severe non-proliferative diabetic retinopathy in South West England.

ABSTRACT

AIMS: To estimate the incidence of early treatment diabetic retinopathy study (ETDRS) level 47 and 53 and progression to treatment with panretinal photocoagulation (PRP) for proliferative DR (PDR). METHODS: Log-linear regression was used to estimate the incidence of level 47-53 or worse for 33,009 people with diabetes (PWD) in Gloucestershire during 2013-2016 by calendar year and diabetes type, based on the first recording. Progression was analysed in Gloucestershire and Bristol with a parametric survival analysis examining the association of baseline and time-varying demographic and clinical factors on time to PRP after the first recording of level 47-53. RESULTS: Incidence decreased from 0.57 (95% confidence intervals (CI) 0.48-0.67) per 100 PWD in 2013 to 0.35 (95% CI 0.29-0.43) in 2016 (p < 0.001). For progression, 338 eligible PWD from Gloucestershire and 418 from Bristol were followed for a median of 1.4 years; 78 and 83% had Type 2 diabetes and a median (interquartile range) of 15 (10-22) and 17 (11-25) years duration of diagnosed diabetes respectively. Three years from the incident ETDRS 47-53, 18.9% and 17.2% had received PRP respectively. For Gloucestershire, severe IRMA and updated mean HbA1c were associated with an increase in the risk of initiating PRP (hazard ratio 3.14 (95% CI 1.60-6.15) and 1.21 (95% CI 1.06-1.38 per 10 mmol/mol) respectively). CONCLUSION: This study provides additional understanding of this population and shows that a high proportion of patients with ETDRS levels 47-53 need to be monitored as they are at high risk of progressing to PDR.