BACKGROUND: Bariatric surgery for obese type 2 diabetes mellitus has obtained better effects in Mainland China, but there is no clear report about bariatric surgery for non-obese type 2 diabetes mellitus.
OBJECTIVE: To assess the clinical effectiveness of bariatric surgery for non-obese type 2 diabetes mellitus in Mainland China.
METHODS: We searched the Cochrane Central Register of Controlled Trials (Issue 2, 2012), MEDLINE (1990 to February 2012), EMbase (1990 to February 2012), CBMdisc (1990 to February 2012) and CNKI (1990 to February 2012). Manual search of relevant journals and conference proceedings was also performed. Clinical trials in which bariatric surgery (gastric bypass) was used to treat patients with type 2 diabetes mellitus in Mainland China were collected. Then we screened the retrieved studies according to predefined inclusion and exclusion criteria, evaluated the quality of the included studies, and performed meta-analyses by RevMan 5.1.0 software.
RESULTS AND CONCLUSION: A total of 30 articles were found and seven articles involving 307 patients were finally included. All these articles were regarded as low quality (grade C). We chose the random-effect model to conduct meta-analysis because significant heterogeneities were found among these articles. The results of meta-analysis showed that after treatment with bariatric surgery, there were significant reductions in fasting plasma glucose [3 months: mean difference (MD)= -2.84, 95% confidence interval (CI) (-3.60, –2.08), P < 0.000 01; 6 months: MD= -3.79, 95%CI (–4.56, –3.02), P < 0.000 01], glycated hemoglobin [3 months: MD= -1.52, 95%CI (-2.14, -0.89), P < 0.000 01; 6 months: MD= -1.90, 95%CI (-2.46, -1.34), P < 0.000 01] and insulin resistance index [6 months: MD= –1.80, 95%CI (–2.68, –0.91), P < 0.000 1]. Sensitivity analysis indicates that results were credible and stable. Funnel-plots display non-symmetrical figures, indicating publication bias. Bariatric surgery is effective for non-obese type 2 diabetes mellitus in Mainland China. However, due to lack of quality in the included studies, more studies with high-quality large-size samples should be conducted.