Risk of bias for studies included in the systematic review
| Study, year | Domain 1: Study participation | Domain 2: Study attrition | Domain 3: Prognostic factor measurement | Domain 4: Outcome measurement | Domain 5: Study confounding | Domain 6: Statistical analysis and reporting | Overall risk of bias |
|---|---|---|---|---|---|---|---|
| Barnes et al., (21) 2008 | High | Low | Low | Low | Moderate | Low | High |
| Moss et al., (1) 2008 | Low | Low | Low | Low | Moderate | Low | Moderate |
| Cohen et al., (20) 2010 | High | Low | Low | Low | Moderate | Low | High |
| Moss et al., (26) 2010 | Moderate | Low | Low | Low | Low | Low | Moderate |
| Da Silva Gane et al., (30) 2013 | Low | Low | Low | Low | Moderate | Low | Moderate |
| Pang et al., (22) 2013 | Low | Moderate | Low | Low | Moderate | Low | Moderate |
| Reilly et al., (23) 2013 | Moderate | Low | Low | Low | Moderate | Low | Moderate |
| Khan et al., (24) 2014 | Low | Low | Low | Low | Moderate | Low | Moderate |
| Moroni et al., (25) 2014 | Moderate | Low | Low | Low | Low | Low | Moderate |
| Feyi et al., (27) 2015 | Low | Low | Low | Moderate | High | Low | High |
| Vick et al., (28) 2015 | Moderate | Moderate | Low | Low | Low | Low | Moderate |
| Gerlach et al., (33) 2016 | Low | Low | Low | Low | Low | Low | Low |
| Amro et al., (31) 2016 | Low | Low | Low | Low | Moderate | Low | Moderate |
| Lefkowits et al., (35) 2016 | Low | Low | Low | Low | Low | Low | Low |
| Carmen et al., (32) 2016 | Low | Low | Low | Low | Moderate | Low | Moderate |
| Lakin et al., (34) 2016 | High | Low | Low | Low | Low | Low | High |
Note: Appendix 1 (available at www.cmaj.ca/lookup/suppl/doi:10.1503.cmaj.160775/-/DC1) provides the details of how judgments were made for the individual domains.