Dopamine treatment delays diabetic retinopathy onset in a retrospective study

Abstract

Purpose : Diabetic retinopathy (DR) is a leading cause of blindness, and world-wide prevalence is expected to increase. Dopamine treatment protects against early neuronal dysfunction in DR in both animal models and people and acts as an anti-angiogenic in models of acute lung injury, cancer, and irritable bowel syndrome. Whether dopamine functions as an anti-angiogenic to reduce clinically-recognized vascular pathology in DR is unknown. Here, we used a retrospective study of Veterans with diabetes to determine whether taking L-DOPA or dopamine agonists delayed DR onset.

Methods : A retrospective analysis of medical records was used to identify patients diagnosed with diabetes, with or without a history of treatment with levodopa or dopamine agonists. The primary outcome was the time interval between initial diabetes diagnosis and DR diagnosis. Patients with >100 days of dopamine prescriptions during the time period between diagnoses (dopamine group, n=424) were compared against patients with no history of dopamine prescriptions (untreated group, n=9952). Other factors compared across groups were age at diabetes diagnosis, gender, race, tobacco usage, co-morbidities, blood sugar control, and insulin/hypoglycemic usage with unpaired t-tests for continuous variables and Chi-square tests for categorical variables. A multivariate linear model was utilized to assess the relative impact of dopamine treatment and other factors on the time to develop DR in Veterans with diabetes. Statistical assessments were performed using RStudio version 1.4.

Results : Dopamine treatment delayed DR onset in Veterans with diabetes by 1.5 years (6.802 vs. 8.381 years, p<0.001). On average, the dopamine group was older (55.01 vs. 57.24, p<0.001), with a higher proportion of female patients (female: 6.4% vs. 3.8%, p<0.001) and a higher Elixhauser co-morbidity score with van Walraven weighting (5.552 vs. 3.338, p<0.001). There was no difference in average HbA_1c between groups. The primary dopamine drugs taken included D2-like agonists (77.4%), dopamine precursors (20.7%), and dopamine degradation enzyme inhibitors (1.9%).

Conclusions : Veterans with diabetes who took L-DOPA and dopamine agonists showed delayed onset of vascular pathology associated with DR. This research demonstrates the value of long-term dopamine treatment for DR. Future research will include a prospective study to examine the protective effects of L-DOPA on vascular pathology in DR.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.