Table 3.
Risk of bias assessment
| Study | Year | Participant selection | Confounding | Measurement of exposure | Blinding | Incomplete outcome data | Total |
|---|---|---|---|---|---|---|---|
| Abdolreza et al27 | 2011 | 1 | 1 | 1 | 1 | 1 | 5 |
| Al Assaad et al28 | 2018 | 2 | 1 | 2 | 1 | 1 | 7 |
| Al-Hadramy et al22 | 1997 | 1 | 1 | 2 | 1 | 1 | 6 |
| Al Mahayni et al20 | 2018 | 1 | 1 | 2 | 1 | 1 | 6 |
| Basiri et al23 | 2004 | 1 | 1 | 2 | 1 | 1 | 6 |
| Cevik et al24 | 2016 | 2 | 2 | 2 | 1 | 1 | 8 |
| Habib et al25 | 2014 | 1 | 1 | 1 | 1 | 1 | 5 |
| Hodgkinson et al26 | 1976 | 1 | 1 | 1 | 1 | 1 | 5 |
| Miladipour et al19 | 2012 | 1 | 1 | 1 | 1 | 1 | 5 |
| Sagy et al21 | 2017 | 2 | 2 | 2 | 1 | 1 | 8 |
Adapted from the RoBANS tool.39 A score of “1” indicates low-risk, “2” indicates high-risk, and “0’ is unclear.