Assessment of the influence of glycemic variability on the central retinal thickness as an early marker of diabetic retinopathy: results of the Brazilian Diabetes study

• Grant number: 21/11436-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: November 01, 2021
• End date: October 31, 2023
• Field of knowledge: Health Sciences - Medicine
• Principal Investigator: Andrei Carvalho Sposito
• Grantee: Daniel Campos de Jesus
• Host Institution: Faculdade de Ciências Médicas (FCM). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Associated research grant: 13/07607-8 - OCRC - Obesity and Comorbidities Research Center, AP.CEPID

Abstract

Diabetic Retinopathy (DR) affects one-third of patients with type 2 Diabetes (DM2), as the main reversible cause of blindness and loss of quality of life in this population. The development of new retinal assessment techniques, in particular optical coherence tomography to measure the central retinal thickness (CRT), stands out as a non-invasive method for detecting patients with early stages of the disease, which timely intervention offers the better potential of therapeutic success. Furthermore, it's known that in diabetics without macular edema, the pathophysiology of diabetes - which involves microvascular disfunction, activation of apoptosis pathways, and systemic inflammatory response - courses with retinal degeneration that promotes CRT reduction. Clinically, patients with reduced CRT are more likely to progress to loss of visual acuity due to retinopathy. In this context, it was previously evidenced that not only poor glycemic control, but also the amplitude of glycemic variability (GV) is related to loss of visual acuity in diabetics. Therefore, the present project was formulated to investigate, in patients with DM2 with preserved visual acuity, whether or not the exposure to greater GV is also related to lower CRT as an early marker of DR. Methods: This project will be a cross-sectional analysis of prospective cohort data from patients involved in the Brazilian Diabetes Study, conducted by the Clinical Research Center at Unicamp. All patients who are associated with a retinal evaluation with CRT measurement at least 2 HbA1c measurements will be included. The GV will be obtained as a mean amplitude of glycemic excursions (MAGE). For comparison purposes, patients above and below the median MAGE to our sample will be classified as high GV (GV +) and low GV (GV -). Consequently, the groups will be used as an independent variable of the ordinal regression model, in which they will have the CRT tertiles as a dependent variable. Thus, the odds ratio between the groups of presenting themselves in the lower tertile of CRT will be explored, using the lower tertile of CRT as reference. This study was approved by the Research Ethics Committee of medical science college (FCM - Unicamp). (AU)