Supplemental Table.
Risk of bias of studies based on the domains of the QUIPs tool (14)
| First author, year | Study participation | Study attrition | Prognostic (predictive) factor measurement | Outcome measurement | Study confounding | Statistical analyses & reporting |
|---|---|---|---|---|---|---|
| Ananthakrishnan, 2012 (18) | Moderate | High | Low | High | High | High |
| Bao, 2017 (28) | Moderate | High | High | High | Moderate | Moderate |
| Cao, 2014 (19) | Moderate | Low | Moderate | Moderate | High | High |
| Cao, 2017 (27) | Low | Low | Moderate | Moderate | High | High |
| Fay, 2013 (20) | High | Low | High | High | High | Moderate |
| Hecht, 2011 (21) | High | Moderate | High | High | High | Moderate |
| Kirpalani, 2014 (22) | Low | Low | High | High | High | Moderate |
| Lee, 2013 (23) | Low | Low | Low | Low | High | Moderate |
| Liapi, 2005 (24) | High | Low | Moderate | Moderate | High | High |
| Noda, 2015 (25) | High | Low | Moderate | Moderate | Moderate | Moderate |
| Sutter, 2016 (26) | Low | Low | Moderate | Moderate | High | Moderate |