Traditional Chinese Patent Medicine for Treating Impaired Glucose Tolerance: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Introduction/Aim: To assess the effectiveness and safety of Traditional Chinese patent medicines (TCPMs) for managing impaired glucose tolerance (IGT). Methods: Seven databases were searched to identify eligible trials published from incepting to May 1, 2016. Randomized controlled trials (RCTs) involving TCPM for IGT with a minimum follow-up duration of 6 months were included for analysis. Data extraction and quality assessment were performed by two reviewers independently. Data synthesis was analyzed using Review Manager 5.3 software. Subgroup analysis was carried out to assess the robustness of results of meta-analysis. Results: Eighteen trials with a total of 3172 participants met the inclusion criteria. The methodological quality of the RCTs was variable. Comparing with receiving lifestyle modification (LM) alone, TCPM plus LM was significantly better at reducing the incidence of diabetes (risk ratio [RR] 0.45; 95% confidence interval [CI] 0.36-0.57, p<0.00001) and normalizing the blood glucose (RR 0.72; 95% CI 0.64-0.82, p<0.00001). TCPM plus LM was superior in decreasing the levels of 2hPG, body mass index (BMI), fasting insulin, and 2h insulin compared with LM alone (2hPG: mean difference [MD] -1.13; 95% CI -1.68 to -0.58, p<0.0001; BMI: MD -0.42; 95% CI -0.71 to -0.14, p=0.004; fasting insulin: MD -2.44; 95% CI -3.79 to -1.09, p=0.0004; and 2h insulin: MD -8.26; 95% CI -8.47 to -8.05, p<0.00001). Compared with placebo plus LM, TCPM plus LM was superior in reducing diabetes (RR 0.54; 95% CI 0.42-0.69, p<0.00001) and normalizing blood glucose (RR 0.55; 95% CI 0.41-0.73, p<0.00001; the interventions were also associated with a decline in the two-hour postprandial blood glucose (2hPG) levels (MD -1.45; 95% CI -2.11 to -0.79, p<0.0001) and BMI levels (MD -1.12; 95% CI -2.00 to -0.24, p<0.0001). There were no significant differences in adverse events between two groups. Subgroup analysis found no significant difference in overall effects among all study characteristics, indicating that the overall effects were stable. Conclusions: The study indicated that TCPM combined with moderate lifestyle modification had significant effect on IGT. Further studies are needed to provide more reliable evidence. The PROSPERO registration is No. CRD42016039312.