Diabetes mellitus as a risk factor for retinal vein occlusion

Retinal vein occlusion (RVO) is the second most common etiology for vision loss. There is contrasting evidence on the association between diabetes mellitus (DM) and the risk of RVO. We performed a meta-analysis of published articles before October 31, 2019, to estimate a pooled odds ratio for the association between DM and RVO, including central and branch RVO by a fixed or random effects model. We identified 37 publications from 38 studies (1 publication was from 2 studies), published between 1985 and 2019. In total, 148,654 cases and 23,768,820 controls were included in this meta-analysis. The results of pooled analysis for all 37 publications (or 38 studies) showed a significant association between DM and the risk of RVO (OR = 1.68, 95% CI: 1.43-1.99). Subgroup analysis indicated that DM was significantly associated with CRVO (OR = 1.98, 95% CI: 1.29-3.03, I = 67.9%), but not significantly associated with BRVO (OR = 1.22, 95% CI: 0.95-1.56, I = 64.1%). In conclusion, the result of present meta-analysis suggested that DM is a risk factor for RVO. More well-designed studies on the relationship between RVO and DM should be undertaken in the future.