The Impact of Bariatric Surgery on Diabetic Retinopathy: A Systematic Review and Meta-Analysis.

Abstract Purpose While bariatric surgery induces remission of type 2 diabetes mellitus and reduces other microvascular complications, its impact on diabetic retinopathy (DR) is unclear. Some trials suggest early worsening of DR post-surgery due to rapid hyperglycemia improvements. This meta-analysis sought to estimate the impact of bariatric surgery on DR for obese patients in comparison to medical treatment. Design Systematic review and meta-analysis Methods MEDLINE, EMBASE, and CENTRAL databases were searched to March 2020. Primary studies comparing DR in patients undergoing bariatric surgery to medical management were included. Results were meta-analyzed using a random-effects model. Primary outcomes included prevalence of all DR and sight-threatening DR after surgery. Secondary outcomes included worsening of DR within and beyond 12 months. Results Overall, 14 studies comprised of 110,300 surgical and 252,289 control patients were included. Surgical patients had statistically significantly lower post-operative prevalence of all DR (RR 0.17 [95% CI, 0.13, 0.22]) and sight-threatening DR (RR 0.47 [95% CI 0.27, 0.82]). Early worsening of DR and progression to sight-threatening DR had occurred more often in those with more severe DR initially. However, beyond 12 months, bariatric surgery resulted in significantly fewer patients with worsened DR (RR 0.29 [95% CI 0.16, 0.54]). Overall risk of bias was low; estimates of relative effects had low to moderate certainty of evidence. Conclusion While bariatric surgery was associated with fewer cases of all and sight-threatening DR, early worsening was more severe in patients with existing sight-threatening DR. These findings argue for frequent monitoring during the first post-operative year.