Table 5.
Assessment the methodological quality of included studies
| Author (yr) | Sample size calculation | Generation of allocation sequence | Allocation concealment | Deviations, withdrawals and dropouts | Efficacy of randomization | Blinding | Definition of outcome parameters |
| Figueras et al (2005) | Yes | No description | Sealed envelope | Yes | Yes | No description | Yes |
| Wu et al (2002) | No description | No description | Sealed envelope | No description | Yes | No description | Yes |
| Yuan et al (2010) | Yes | Yes | Sealed envelope | Yes | Yes | Single-blinded | No description |
| Liang et al (2009) | No description | No description | No description | Yes | Yes | No description | Yes |