TABLE 3.
Assessment of risk of bias for randomized controlled trials
| Study ID | A | B | C | D | E | F |
|---|---|---|---|---|---|---|
| Peng (2010) | Probably low | Probably low | Probably high | Low | Probably high | Low |
| Yan et al. (2012) | Probably low | Probably low | Probably high | Probably low | Probably high | Low |
| Song et al. (2013) | Probably low | Probably low | Probably high | Low | Probably high | Low |
| Ma et al. (2014) | Low | Probably low | Probably high | Probably low | Probably high | Low |
| Wang et al. (2014) | Low | Probably low | Probably high | Low | Probably high | Low |
| Li et al. (2015) | Probably low | Probably low | Probably high | Low | Probably high | Low |
| Wei (2017) | Probably low | Probably low | Probably high | Low | Probably high | Low |
| Ma et al. (2018) | Low | Probably low | Probably high | Low | Probably high | Low |
| Zhang et al. (2018) | Low | Probably low | Probably high | Low | Probably high | Low |
| Li et al. (2018) | Low | Low | Low | Probably low | Probably high | Low |
| Liu et al. (2019) | Probably low | Probably low | Probably high | Probably low | Probably high | Low |
| Han (2019) | Low | Probably low | Probably high | Probably low | Probably high | Low |
Note: “A” was the allocation sequence adequately generated?; “B” was the allocation adequately concealed?; “C” blinding was knowledge of the allocated interventions adequately prevented?; “D” was loss to follow‐up (missing outcome data) infrequent?; “E” are reports of the study free of selective outcome reporting?; “F” was the study apparently free of other problems that could put it at a risk of bias?; Low, low risk of bias; Probably low, Probably low risk of bias; Probably high, Probably high risk of bias.