Risk of stroke in patients with diabetic retinopathy: A systematic review and meta-analysis

Objective: Diabetic retinopathy (DR) is a microvascular complication of diabetes that occurs at high frequencies (more than 20%) during the course of the disease. Therefore, we conducted a meta-analysis of the incidence of stroke in DR to determine whether DR is associated with stroke. Methods: The PubMed, Embase and Cochrane databases were systematically searched from their inception to December 1, 2022. Randomized controlled trials (RCTs) that reported DR and stroke events were included. The pooled risk ratio and 95% confidence interval (CI) were calculated. For the incidences of DR and stroke, risk difference and standard error were measured. Sensitivity analysis was performed to assess whether any single study could affect the overall outcome. Results: Nine RCTs involving 46,599 patients with diabetes were included in this meta-analysis. The incidence of DR in all patients was 0.29 (95% CI 0.20-0.38). The incidence of any stroke in all patients was 0.03 (95% CI 0.03-0.04). The incidence of any stroke in patients with DR was 0.05 (95% CI 0.04-0.07), significant higher than that in all diabetes patients. The pooled risk ratio of stroke in patients with DR was 2.04 (95% CI 1.25-3.32). The estimated risk ratio of stroke in patients with DR without additional conditions was 1.70 (95% CI 1.43-2.03), which was lower than that in patients with DR with additional conditions (2.29, 95% CI 0.93-5.65). Conclusion: The presence of DR is associated with an increased risk of stroke. Our findings indicate that DR is an important biomarker for the prediction of stroke, and periodic eye examinations should be conducted for stroke prevention.