Bias and methodologic quality of the systematic reviews included in this review
| Study | Design of the included studies | Quality assessment | Reason(s) for downgrading (if applicable) |
|---|---|---|---|
| Campbell et al. 2001 (45) | RCT | +++○ Moderate | Indirectness |
| Covarrubias-Gomez 2008 (48)* | Unclear | Not enough information | |
| Deshpande et al. 2015 (41) | RCT | ++○○ Low | Risk of bias, indirectness |
| Fitzcharles et al. 2016 (42) | RCT | ++○○ Low | Risk of bias, indirectness |
| Hwang et al. 2016 (32) | RCT | ++○○ Low | Risk of bias, inconsistency |
| Khaiser et al. 2016 (33) | Observational | +○○○ Very low | Risk of bias, indirectness |
| Kung et al. 2011 (49)* | RCT | Not enough information | |
| Lynch and Ware 2015 (46) | RCT | +++○ Moderate | Risk of bias |
| MacFarlane et al. 2011 (47) | RCT | +++○ Moderate | Publication bias |
| Martín-Sánchez et al. 2009 (43) | RCT | ++○○ Low | Risk of bias, indirectness |
| Stevens and Higgins 2017 (44) | RCT | ++○○ Low | Inconsistency, indirectness |
| Wang et al. 2008 (40) | Observational | +○○○ Very low | Risk of bias, inconsistency, indirectness |
RCT = randomized controlled trial.
↵* Abstract only.