Incidence and progression of diabetic retinopathy within a private diabetes mellitus clinic in South Africa

  • Rebecca Louise Thomas
  • Larry Distiller Centre for Diabetes and Endocrinology
  • V J Melville Centre for Diabetes and Endocrinology
  • S Roy Chowdhury Cardiff University
  • B Kramer Centre for Diabetes and Endocrinology
  • D R Owens Swansea University
Keywords: diabetes mellitus, diabetic retinopathy, epidemiology, incidence, risk factors, South Africa

Abstract

Objective: The study objective was to examine the influence of glycaemic control and ethnic variations on the incidence and progression of diabetic retinopathy (DR). Design, subjects and setting: Eight hundred and ninety-two persons with type 1 diabetes mellitus, and 1 998 persons with type 2 diabetes mellitus, who were enrolled in a private diabetes mellitus management programme in South Africa, participated in the study. Survival analyses were conducted to assess the relationship between the risk factors and the incidence of DR and referable DR, and the progression of DR. Outcome measures: Cumulative incidence of diabetic retinopathy and referable diabetic retinopathy. Results: The seven-year cumulative incidence of DR and referable DR was 536 and 50 cases per 1 000 persons with type 1 diabetes mellitus without DR at baseline, and 351 and 47 cases per 1 000 persons with type 2 diabetes mellitus. The seven-year cumulative incidence of referable DR was 332 cases per 1 000 persons with type 1 diabetes mellitus with background DR at baseline, and 360 cases with type 2 diabetes mellitus, representing a seven- and eightfold increase compared to no DR at baseline. After controlling for known risk factors for DR, a high baseline haemoglobin A1c (HbA1c) and non-caucasian ethnicity were associated with the incidence of referable DR in patients with type 1 and type 2 diabetes mellitus. Conclusion: It was revealed in the first study to report on the incidence and progression of DR in South Africa that a high baseline HbA1c, ethnicity, and the presence of background DR increased the risk of the development of referable DR. (Full text available online at www.medpharm.tandfonline.com/oemd) Journal of Endocrinology, Metabolism and Diabetes of South Africa 2015; DOI: 10.1080/16089677.2015.1090159

Author Biographies

Rebecca Louise Thomas
Diabetes Reseach Unit, Cymru Research Officer
Larry Distiller, Centre for Diabetes and Endocrinology
Centre for Diabetes and Endocrinology Johannesburg
V J Melville, Centre for Diabetes and Endocrinology
Centre for Diabetes and Endocrinology Johannesburg
S Roy Chowdhury, Cardiff University
Institute of Molecular and Experimental Medicine Cardiff University Cardiff
B Kramer, Centre for Diabetes and Endocrinology
Centre for Diabetes and Endocrinology Johannesburg
D R Owens, Swansea University
Diabetes Research Unit Swansea University Swansea
Published
2015-12-10
Section
Research Articles