Preoperative Fasting Plasma C-Peptide Levels as Predictors of Remission of Type 2 Diabetes Mellitus after Bariatric Surgery: A Systematic Review and Meta-Analysis.

AIMS: The study evaluated the predictive role of preoperative fasting C-peptide, hemoglobin (Hb)A1c, fasting plasma glucose (FPG), and body mass index (BMI) levels on diabetes remission in patients with type 2 diabetes following bariatric surgery.

METHODS: Medline, PubMed, Central, and Google Scholar databases of up to September 7, 2016 were searched using the following terms: type 2 diabetes mellitus, gastric bypass, Roux-en-Y, anastomosis, C-peptide, weight loss, HbA/HbA1c, predictive/predictor.

RESULTS: Meta-analysis of the pooled data indicated that fasting C-peptide was predictive of increased chance of remission of type 2 diabetes (pooled difference in means = 0.93, 95% confidence interval [CI] = 0.61 to 1.25, p < .001). The analysis also found that FPG (pooled standardized mean difference = -0.42, 95% CI: -0.64 to -0.20, p < .004) and HbA1c levels (pooled difference in means = -1.05, 95% CI: -1.48 to -0.62, p < .001) were associated with reduced odds of type 2 diabetes remission. BMI was not found to be associated with remission (pooled difference in means = 0.29, 95% CI: 0.30 to 0.88, p = .343). In general, subgroup analysis, which evaluated the pooled data from the retrospective and prospective studies separately, gave similar results.

CONCLUSIONS: Preoperative fasting plasma C-peptide was associated with increased type 2 diabetes remission after bariatric surgery, whereas baseline HbA1c and FPG levels were associated with reduced chance of remission. These parameters may be used as a guideline in weighing the risks and benefits for surgical intervention in patients with type 2 diabetes.