Data extraction
Two authors (Q.Y.Q. and W.K.E.) independently reviewed studies to
extract potentially eligible studies. Any discrepancies were resolved by
consensus with the corresponding author (X.Z.H). The main outcomes
(reduction of FPG and HbA1c) for each study were extracted or
calculated, and the adverse events (AEs) were collected. For
consistency, we collected all per-protocol analysis data. In addition,
the clinical characteristics of each study were also summarized.