Efficacy and safety of Gegen Qinlian decoction for normalizing hyperglycemia in diabetic patients: A systematic review and meta-analysis of randomized clinical trials

Objectives: A systematic review and meta-analysis was conducted to evaluate the efficacy and safety of Gegen Qinlian decoction (GQD) for normalizing hyperglycemia in T2DM patients by pooling all available RCTs. Methods: All relevant RCTs were searched using the keywords: "GQD", "T2DM", "hyperglycemia" and "insulin" from the electronic databases including PubMed, EMBASE, Cochrane Library, Korean databases, Chinese medical databases, and Indian scientific database. Each RCT included the control (metformin) and experimental (GQD + metformin) groups. The outcome measures were the assessments of changes in the severity of diabetic symptoms such as "markedly effective" and "effective" (fasting plasma glucose levels: < 7 and 7-9, respectively; 2 h postprandial glucose levels: < 8.3 and 8.3-10.5 mmol/L, respectively) after 8 weeks of treatment in each RCT. Results: There were 186 articles selected from the initial searches and 181 irrelevant and duplicate articles were removed. Finally, 5 relevant RCTs involving 499 patients were included in this review. The meta-analysis showed the odds ratio of favorable GQD effect on the marked effectiveness of glycemia (n = 499, OR: 2.34, 95% CI: 1.63-3.37, P < 0. In a subgroup analysis by GQD composition, 4 RCTs with original GQD composition also showed the odds ratio of the original GQD effect on the marked effectiveness of glycemia (n = 339, OR: 2.58; 95% CI = 1.65-4.02, P < 0.0001) in comparison to the control group. All five studies used an appropriate method for randomization of the subjects but some of them included allocation concealment and blinding of patients and practitioners. There was no significant publication bias in the meta-analysis. Conclusion: The GQD and metformin had a synergistic effect on glycemic control in comparison to metformin alone as a T2DM therapy. More rigorous and larger studies are needed to confirm the therapeutic efficacy of GQD for hyperglycemia due to the moderate to high risk of bias in the 5 RCTs.