ObjectivesTo compare the effects of different bariatric surgeries on reducing hemoglobin A1c (HbA1c) in overweight/obese patients with type 2 diabetes.MethodsRandomized controlled trials (RCTs) of bariatric surgery were systematically searched in PubMed, EMbase, The Cochrane Library, ClinicalTrials.gov, CNKI, WanFang Data and VIP databases from inception to February 20th, 2019. Two reviewers independently screened literature, extracted data and assessed risk of bias of included studies, then, meta-analysis was performed by using Stata 14.0 software and R 3.6.2 software.ResultsA total of 24 RCTs were included. Compared with non-surgical treatments, 5 out of 9 procedures significantly reduced HbA1c, and the probability order for the effect was as follows: sleeve gastrectomy with transit bipartition (SGTB) (MD=?3.60%, 95%CI ?5.89 to ?1.31, P=0.002), mini-gastric bypass (MGB) (MD=?2.36%, 95%CI ?4.13 to ?0.58, P=0.009), duodenal-jejunal bypass liner (DJBL) (MD=?1.85%, 95%CI ?2.75 to ?1.96, P<0.000 01), sleeve gastrectomy (SG) (MD=?1.48%, 95%CI ?2.49 to ?0.47, P=0.004), and Roux-en-Y gastric bypass (RYGB) (MD=?1.31%, 95%CI ?2.02 to ?0.59, P=0.003). The effects of biliopancreatic diversion with duodenal switch and gastric plication were uncertain. Adjustable gastric banding and Roux-en-Y gastrojejunostomy had no significant effects on HbA1c. Because of the limitations of small sample size and high risk of bias, the results of SGTB requires further validation. ConclusionsThe current evidence suggests that the bariatric surgeries that have relatively beneficial effects for lowering HbA1c treatment are MGB, DJB, SG and RYGB in sequence.
