Table 1.
Risk of bias of the included studies.
| Study | Random sequence generation | Allocation concealment | Blinding | Incomplete outcome data | Selective reporting | Other bias | |
|---|---|---|---|---|---|---|---|
| Patient/doctor blinding | Outcome assessor blinding | ||||||
| Ballegaard et al. [26] | Uncertain | Uncertain | Low risk | Low risk | Uncertain | Uncertain | Uncertain |
| Chang [27] | Uncertain | Uncertain | Uncertain | Uncertain | Low risk | Uncertain | Uncertain |
| Deng et al. [28] | Uncertain | Uncertain | Uncertain | Uncertain | Low risk | Uncertain | Uncertain |
| Diao et al. [29] | Uncertain | Uncertain | Uncertain | Uncertain | Low risk | Uncertain | Uncertain |
| Fan et al. [30] | Central randomization | Low risk | Uncertain | Low risk | Low risk | Uncertain | Uncertain |
| He et al. [31] | Uncertain | Uncertain | Uncertain | Uncertain | Low risk | Uncertain | Uncertain |
| Jie et al. [32] | Clinical record number | High risk | Uncertain | Uncertain | Low risk | Uncertain | Uncertain |
| Huang et al. [14] | Random number table | Uncertain | Uncertain | Uncertain | Low risk | Uncertain | Uncertain |
| Dan et al. [33] | Uncertain | Uncertain | Uncertain | Uncertain | Uncertain | Uncertain | Uncertain |
| Li and Li [34] | Random number table | Uncertain | Uncertain | Uncertain | Low risk | Uncertain | Uncertain |
| Li et al. [35] | Random number table | Uncertain | Uncertain | Uncertain | Low risk | Uncertain | Uncertain |
| Lin et al. [36] | Uncertain | Uncertain | Uncertain | Uncertain | Low risk | Uncertain | Uncertain |
| Liu et al. [12] | Uncertain | Uncertain | Uncertain | Uncertain | Low risk | Uncertain | Uncertain |
| Liu and Zhang [37] | Random number table | High risk | Uncertain | Uncertain | Low risk | Uncertain | Uncertain |
| Ma et al. [38] | Uncertain | Uncertain | Uncertain | Uncertain | Low risk | Uncertain | Uncertain |
| Jiang et al. [39] | Clinical record number | High risk | Low risk | Uncertain | Low risk | Uncertain | Uncertain |
| Youfa and Chen [40] | Uncertain | Uncertain | Uncertain | Uncertain | Low risk | Uncertain | Uncertain |
| Rlchter Jhaah et al. [41] | Uncertain | Uncertain | Uncertain | Uncertain | Uncertain | Uncertain | Uncertain |
| Wang et al. [42] | Random number table | High risk | Uncertain | Low risk | Low risk | Uncertain | Uncertain |
| Shen et al. [43] | Random number | Uncertain | Uncertain | Uncertain | Low risk | Uncertain | Uncertain |
| Pingchang and Shizhao [44] | Random number table | High risk | Uncertain | Uncertain | Low risk | Uncertain | Uncertain |
| Yang [45] | Uncertain | Uncertain | Uncertain | Uncertain | Uncertain | Uncertain | Uncertain |
| Yang et al. [46] | Random number | Low risk | Uncertain | Low risk | Low risk | Uncertain | Uncertain |
| Zhang [47] | Uncertain | Uncertain | Uncertain | Uncertain | Low risk | Uncertain | Uncertain |
| Zhang et al. [16] | Random number | High risk | Uncertain | Low risk | Low risk | Uncertain | Uncertain |
| Zhang et al. [48] | Random number | High risk | Uncertain | Low risk | Low risk | Uncertain | Uncertain |
| Zhao et al. [13] | Central randomization | Low risk | Low risk | Low risk | Low risk | High risk | High risk |