Study of The Relationship between Diabetic Retinopathy, Basal Insulin Therapy (Glargine Or NPH) And Insulin-Like Growth Factor 1 Serum Level

Background: Globally, the leading cause of avoidable blindness is diabetic retinopathy (DR). Diabetes mellitus (DM) type 1 (T1DM) individuals are more likely to develop DR, a microvascular consequence of the disease. As an autoimmune condition that causes insulin insufficiency, T1DM patients need basal insulin therapy throughout the duration of their treatment to achieve optimum glycemic control. An essential growth factor involved in angiogenesis and cell proliferation is insulin-like growth factor 1 (IGF-1). IGF-1 has a strong correlation with DR development, according to a wealth of data. In contrast to the intermediate-acting NPH insulin, insulin glargine is a long-acting insulin analogue that is peak-free and less hypoglycemic. The enhanced affinity of glargine for the IGF-1 receptor has sparked questions regarding its potential involvement in the development of DR. There is ongoing discussion on the connection between IGF-1 blood levels, basal insulin treatment, and diabetic retinopathy. Objective: We wanted to assess the frequency and severity of DR in T1DM patients on basal insulin treatment (Glargine or NPH) and its relationship with blood IGF-1 levels. Patients and Methods: A cross-sectional comparative study that included 88 patients conducted at Ain Shams University Hospital, Diabetology Clinic. It was conducted from October 2021 till February 2022. Subjects were divided into 44 T1DM patients on baseline insulin therapy with glargine and Actarapid (Group A) and 44 on insulin NPH and Actarapid (Group B). Results: Regarding the fundus examination results between the two groups under study, there was no statistically significant difference (P value = 0.429). Serum IGF-1 and diabetic retinopathy did not significantly correlate (P =0.080, mean±SD of serum IGF-1 level in cases with normal fundus 14.8±11 vs. those with diabetic retinopathy 21.3±16.9). Diabetes duration and diabetic retinopathy were statistically significantly correlated (P value <0.05, mean±SD of diabetes duration in patients with DR 17.7 ± 6.9 vs. those with normal fundus 14.6 ± 5.6). The mean ± standard deviation of age in Group B regimen was 28.4 ± 6.7, while in Group A, it was 25.5 ± 4.9. This difference was statistically significant. Conclusion: There was no statistically significant difference in serum IGF-1 levels between patients with normal fundus or DR, or between individuals on glargine or NPH. In individuals with T1DM, the severity and frequency of diabetic retinopathy are closely correlated with the duration of the condition. There is no discernible difference in the alterations in diabetic retinopathy between glargine and NPH patients receiving basal insulin treatment.