Table 1 Information about the six trials
Study | Year | Country | Blinding | Randomization | Random sequence generation | Withdrawals and dropouts | Allocation concealment | Jadad score |
|---|---|---|---|---|---|---|---|---|
Oláh et al. [26] | 2002 | Hungary | Unclear | Yes | Unclear | 0/0 | Unclear | 2 |
Li et al. [25] | 2007 | China | None | Yes | Unclear | Unclear | Unclear | 1 |
Oláh et al. [27] | 2007 | Hungary | Double-blinded | Yes | Unclear | 0/0 | Yes | 3 |
Besselink et al. [23] | 2008 | Netherlands | Double-blinded | Yes | Computer-generated, permuted-block sequence | 2/5 | Yes | 5 |
Plaudis et al. [28] | 2012 | Latvia | Unclear | Unclear | Unclear | 0/0 | Unclear | 1 |
Cui et al. [24] | 2013 | China | None | Yes | Unclear | Unclear | Unclear | 1 |