| Author | Random sequence generation | Allocation scheme hiding | Blind method | Blind method evaluation of the outcome | Result data integrity | Selective reporting of research findings | Other sources of bias | The Jadad score |
| Zhang 2017 [8] | Random number table, low | Dimness | Dimness | Dimness | Dimness | No, low | Low | 2 | Zheng 2014 [9] | The order of visits was random and low | Dimness | Dimness | Dimness | Dimness | No, low | Low | 2 | Zhang 2015 [10] | Random number table, low | Dimness | Dimness | Dimness | Complete, low | No, low | Low | 3 | Zhang 2017 [11] | Yes, dimness | Dimness | Dimness | Dimness | Complete, low | No, low | Low | 2 | Dong 2012 [12] | The order of visits was random and low | Dimness | Dimness | Dimness | Dimness | No, low | Low | 2 | Zhang 2019 [13] | Random number table, low | Dimness | Dimness | Dimness | Complete, low | No, low | Low | 3 | Lin 2018 [14] | Random number table, low | Dimness | Dimness | Dimness | Complete, low | No, low | Low | 3 | Shi 2020 [15] | Random number table, low | Dimness | Dimness | Dimness | Complete, low | No, low | Low | 3 | Gong 2019 [16] | Yes, dimness | Dimness | Dimness | Dimness | Dimness | No, low | Low | 1 | Li 2017 [17] | Yes, dimness | Dimness | Dimness | Dimness | Dimness | No, low | Low | 1 | Zhu 2016 [18] | Random number table, low | Dimness | Dimness | Dimness | Complete, low | No, low | Low | 3 |
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