Efficacy
Among these included trails, five trails19-23 provided the main outcome of FPG after 2-120 days of treatment. As shown inFigure 2 , GKAs reduced the FPG compared with the placebo group (mean difference -0.71, 95% CI: -1.11 to -0.31, P=0.0005). And we performed a subgroup analysis based on whether metformin was included in the treatment regimen. As shown in Figure 3 , we found that GKAs with metformin reduced the FPG compared with the placebo group (mean difference -0.72, 95% CI: -1.12 to -0.31, P=0.0006), but GKAs without metformin did not affect the FPG significantly (mean difference -0.52, 95% CI: -2.57 to 1.53, P=0.62).
Besides, four trails14,19-21 reported the decrease of HbA1c after 60-120 days, which indicates the stability of blood glucose control during the study period. As shown in Figure 4 , the efficacy of oral GKAs on the HbA1c was comparable between GSK and placebo groups(difference in means -0.65, 95% CI: -0.82 to -0.48, P <0.00001). These data indicate that GKAs has a relatively stable efficacy on blood glucose control during the study period.