First author (year) | Internal validity (Cochrane Collaboration’s tool for assessing risk of bias) | External validity | Precision | Overall quality | ||||||
Selection bias | Performance bias | Detection bias | Attrition bias | Reporting bias | Other | |||||
Random sequence generation | Allocation concealment | Blinding of patients and staff | Blinding of outcome measures | Completeness of outcome data | Selective reporting | |||||
Gatz (2020)37 | Low | Low | High | High | Low | High | Low | Low | Low | Poor |
Clifford (2019)17 | Low | Low | High | High | Low | High | High | Low | High | Poor |
Holden (2020)22 | Low | Low | Low | High | Low | Low | Low | Low | Low | Good |
Vuvan (2020)34 | Low | Low | High | Low | Low | Low | Low | Low | Low | Good |
Dupuis (2018)31 | Low | Low | Low | Low | Low | Low | High | Low | Low | Good |
Parle (2017)32 | Low | Low | High | Low | Low | Low | High | Low | High | Poor |
Rio (2017)35 | Low | Low | High | High | High | Low | High | High | High | Poor |
Stasinopoulos (2017)33 | Low | ? | High | Low | Low | Low | ? | High | High | Poor |
van Ark (2015)36 | Low | Low | High | High | High | Low | High | High | High | Poor |
Rio (2015)20 | Low | Low | High | ? | Low | Low | High | High | High | Poor |
?: unclear risk of bias.