Bariatric surgery may reduce diabetic retinopathy (DR) among some patients with type 2 diabetes mellitus (T2DM), according to findings published in the American Journal of Ophthalmology. 

Researchers performed a systematic review and meta-analysis of 14 studies in the MEDLINE, EMBASE and CENTRAL databases, which included a total of 110,300 surgical patients and 252,289 controls, of whom 0.45% and 1.03%, respectively, experienced DR initially. Researchers sought to discover the prevalence of all DR and sight-threatening DR after surgery, as well as worsening DR within and beyond 12 months.  

Results of the analysis show that, for surgical patients, the prevalence of all DR and sight-threatening DR were statistically significantly lower than the nonsurgical group. Additionally, although early worsening and progression of DR to sight-threatening was more common among those with more severe initial DR, the researchers found that significantly fewer patients (RR = .29) had worsened DR beyond 12 months of having bariatric surgery.


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The study explains that 35.4% of people with T2DM experience DR, and that within 10 years, 17% progress from having existing DR to proliferative retinopathy. The researchers say that many patients with T2DM and obesity seek bariatric surgery due to its effectiveness in leading to diabetes remission and improved glucose control. However, they say, past evidence of improving DR has conflicted, and in general, some important outcome measures have never been sought. 

“Although the incidence of bariatric surgery has doubled over the last decade in the United States, no current evidence-based guidelines exist regarding ophthalmologic screening before surgery and follow-up post-surgery,” the study explains.

Additionally, the current analysis looked to compare the short- and long-term effects of bariatric surgery vs no surgery on patients with T2DM and obesity specifically. The researchers explain that prior reviews of this nature either fail to include either non-surgical controls or cohort studies, which would have shed more light on these effects.

The study explains that there are several limitations to this analysis. First, 12 of the 14 studies were observational, and therefore subject to selection bias. Also, only 3 studies used either fluorescein angiography or OCT for the diagnosis of DR, and furthermore, since the prevalence of DR was low across all studies, there was limited outcome data available for analysis.

Reference

Yu CW, Park LJ, Pinto A, et al., The impact of bariatric surgery on diabetic retinopathy: a systematic review and meta- analysis. Am J Ophthalmol. Published online January 8, 2021. doi:10.1016/j.ajo.2020.12.033