Glycated haemoglobin in the first year after diagnosis of type 1 diabetes is an independent risk factor for diabetic retinopathy: The IMDIAB 25 years follow-up study

Background: Intensive glycemic control reduces the risk of diabetic retinopathy (DR) in people with type 1 diabetes (T1D) . However, the impact of glycemic control during the peri-diagnostic period on the long-term risk of DR is not known.Aim: To evaluate the association between the glycemic control obtained within the first year after T1D diagnosis and the long-term risk of DR. Methods: We retrospectively studied a cohort of 150 subjects enrolled within 1 year of T1D diagnosis in intervention trials conducted by the IMmunotherapy DIABetes (IMDIAB) group between 1994 and 20 and still attending follow-up visits in one of the IMDIAB centers. Data regarding clinical and biochemical features at T1D onset and during the first year of the disease were collected at the time of enrollment in the IMDIAB studies. Follow-up data about clinical features including presence of chronic complications were collected between January 2020 and January 2021 through the consultation of medical records. Results: After a median follow-up of 25 [25th-75th percentiles: 22-28] years, 26 (17.3%) people had developed DR. People with DR showed significantly higher updated first-year HbA1c (6.8 [6.2-7.8] % vs. 6.3 [5.7-7.2] %, p=0.037) and higher HbA1c at follow-up (8.0 [6.9-8.9]% vs. 7.2 [6.5-7.8]%, p=0.005) compared to people free from DR. Higher updated first-year HbA1c was also a significant predictor of higher HbA1c at follow-up (beta-coefficient: 0.24, p=0.015) . The association between the updated first-year HbA1c and DR did not significantly change after adding HbA1c at follow-up and disease duration in the multivariate model. Conclusion: Glycemic control obtained during the very first year after T1D onset is associated with long-term risk of diabetic retinopathy independently from subsequent glycemic control and other confounders. Disclosure E.Maddaloni: Consultant; Merck KGaA, Speaker's Bureau; Abbott, Medical Technology & Devices, PIKDARE S.p.A. C.Moretti: None. N.Visalli: Consultant; Sanofi. F.Tramontana: None. A.Crino: None. R.Schiaffini: Advisory Panel; Abbott, Sanofi. R.Buzzetti: Board Member; Lilly, Novo Nordisk, Sanofi, Speaker's Bureau; Abbott, AstraZeneca. P.Pozzilli: Advisory Panel; Dompé, Consultant; Abbott, Speaker's Bureau; Dompé, Lilly Diabetes, Medtronic, Sanofi. Imdiab study group: n/a. A.Carlone: None. D.Pitocco: None. G.Leanza: None. C.Suraci: None. M.Altomare: None. M.G.Cavallo: Advisory Panel; Eli Lilly and Company, Board Member; Novo Nordisk, Speaker's Bureau; AstraZeneca, Sanofi. I.Barchetta: None. S.Morano: None. Funding Italian Ministry of University and Research (PRIN 2017: 20175L9H7H)