Incidence of diabetic retinopathy in newly diagnosed subjects with type 2 diabetes mellitus over 5 years: Contribution of Β-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 HbA (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 (M) (p = 0.025), lower (p = 0.000) postprandial β-cell responsiveness (M) 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.