Prospective Association between Diabetic Retinopathy and Cardiovascular Disease-A Systematic Review and Meta-analysis of Cohort Studies.

BACKGROUND: Diabetic retinopathy (DR) is linked to increased risk of cardiovascular (CV) disease. However, the effect size of the association was not consistent. In this study, we performed a systematic review and meta-analysis of available cohort studies to determine the association between DR and CV disease, and to investigate the factors that influence the association.

METHODS: Terms related to DR and CV disease were searched from MEDLINE and EMBASE database. High-quality articles (Newcastle-Ottawa scales above 6) conducted in cohort studies reporting the association between DR and CV disease were identified. Study-specific estimates were pooled using random effects with inverse variance meta-analysis. Subgroup analysis was performed according to diabetes types. Heterogeneity of included studies was assessed using the I(2) test. The cause of the heterogeneity was examined using metaregression analyses.

RESULTS: A total of 13 studies representing 17,611 patients without CV disease at baseline were included. At follow-up, there were 1457 CV disease-related incidences. Overall, DR was associated with increased risk of CV disease (relative risk [RR]: 2.42, 95% confidence interval [CI]: 1.77-3.31) in diabetes. Specifically, the RR was 3.59 (95% CI: 1.79-7.20) for type 1 diabetes and 1.81 (95% CI: 1.47-2.23) for type 2 diabetes. Significant heterogeneity was found in studies with type 1 diabetes. Metaregression analysis showed that baseline systolic blood pressure was a key factor leading to the heterogeneity.

CONCLUSION: In conclusion, DR is significantly associated with CV disease incidence and CV disease-related mortality in diabetes. Patients with DR may need more intensive management to control future CV disease attacks.