The Association Between Mean Glycated Haemoglobin or Glycaemic Variability and the Development of Retinopathy in People with Diabetes: A Retrospective Observational Cohort Study.

Introduction: To determine the association between mean glycated haemoglobin (HbA) or glycaemic variability and the development of diabetic retinopathy (DR) in people with diabetes.

Methods: An observational cohort study with people registered with a DR eye screening service between October 2012 and October 2017. Those who had no DR at the start of the study were followed for a maximum of 5 years. HbA measures were used to calculate HbA variability and mean HbA to assess any relationship between these and the risk of developing new onset DR.

Results: A total of 2511 individuals were followed up for up to 5 years. Of these, 542 (21.6%) developed DR. After adjustment, HbA variability was not significantly associated with the development of DR (p = 0.3435). However, the mean HbA was (p < 0.0001). Those with type 1 diabetes had an odds of 1.63 (95% CI 1.11-2.40) of a retinopathy diagnosis compared to those with type 2 diabetes.

Conclusions: We have shown that mean HbA is associated with an increased risk of developing diabetic retinopathy. However, after adjustment for sex, age, diabetes type and the mean, the HbA variability no longer remained significant. Our data suggest that optimizing long-term glycaemic control remains paramount.