Incidence of diabetic retinopathy in newly diagnosed subjects with type 2 diabetes mellitus over 5 years: Contribution of B-cell function

Aims Identifying and modulating risk factors is essential to prevent visual impairment due to diabetic retinopathy (DR). This study examines incident DR with metabolic and hormonal factors in newly-diagnosed, treatment naïve, individuals with Type2 Diabetes Mellitus (T2DM), over a 5 year period from diagnosis. Methods 233 T2DM subjects underwent serial DR screening using digital photography and standardised Meal Tolerance Tests at diagnosis and after 1, 2 and 5 years. Subjects (179) with no DR throughout the 5-year study period were compared with those who developed DR (54). Results Of 233 subjects, 54(23.2%) developed DR by 5 years, background DR in 50(93%) and exudative maculopathy in 4(7%) individuals. Of these subjects, 12(22%) developed DR after 1 year, 15(28%) after 2 years and 27(50%) after 5 years. At baseline, those with DR at 5 years had higher HbA1c (p = 0.017), higher fasting plasma glucose (PG) (p = 0.031) and postprandial PG (p = 0.009). They were associated with reduced basal β-cell secretory function (M0) (p = 0.025), lower (p = 0.000) postprandial β-cell responsiveness (M1) and β-cell function (HOMA-B) (p = 0.044). Conclusions There is an independent association between glycaemic control and β-cell dysfunction at the time of diagnosis of T2DM, with incident DR over a follow-up period of 5 years