Table A2.
Risk of Bias assessment according to SIGN methodology checklist.
| Author | 1. Question | 1. Selection | 1. Assessment | 1. Confounding | 1. Statistical Analysis | 2. Quality | Notes |
|---|---|---|---|---|---|---|---|
| Dahan et al. [18] | 1.1 = Yes | 1.2 = Yes | 1.7 = Yes | 1.13 = Yes | 1.14 = Yes | 2.1 = High | |
| 1.5 = 7% | 1.10 = Yes | 2.2 = Yes | |||||
| 1.6 = Yes | 1.11 = Yes | 2.3 = Yes | |||||
| Kabukçu et al. [19] | 1.1 = Yes | 1.2 = Yes | 1.7 = Yes | 1.13 = Yes | 1.14 = No | 2.1 = Acceptable | Went from high to acceptable quality, because of missing confidence intervals. |
| 1.5 = 10% | 1.10 = Yes | 2.2 = Yes | |||||
| 1.6 = Yes | 1.11 = Yes | 2.3 = Yes | |||||
| Agarwal et al. [20] | 1.1 = Yes | 1.2 = Yes | 1.7 = Yes | 1.13 = Yes | 1.14 = Yes | 2.1 = Low | n = 7, therefore low quality. |
| 1.5 = Not reported | 1.10 = Yes | 2.2 = No | |||||
| 1.6 = NA | 1.11 = Yes | 2.3 = Yes | |||||
| Borges et al. [21] | 1.1 = Yes | 1.2 = Yes | 1.7 = Yes | 1.13 = Yes | 1.14 = Yes | 2.1 = High | |
| 1.5 = 0% | 1.10 = Yes | 2.2 = Yes | |||||
| 1.6 = NA | 1.11 = Yes | 2.3 = Yes | |||||
| Vahidi et al. [22] | 1.1 = Yes | 1.2 = Yes | 1.7 = Yes | 1.13 = Yes | 1.14 = No | 2.1 = Acceptable | Went from high to acceptable quality, because of missing confidence intervals. |
| 1.5 = 0% | 1.10 = Yes | 2.2 = Yes | |||||
| 1.6 = NA | 1.11 = Yes | 2.3 = Yes | |||||
| Comar et al. [23] | 1.1 = Yes | 1.2 = Yes | 1.7 = Yes | 1.13 = Yes | 1.14 = Yes | 2.1 = High | |
| 1.5 = 0% | 1.10 = Yes | 2.2 = Yes | |||||
| 1.6 = NA | 1.11 = Yes | 2.3 = Yes | |||||
| Uppangala et al. [24] | 1.1 = Yes | 1.2 = Yes | 1.7 = Yes | 1.13 = Yes | 1.14 = No | 2.1 = Acceptable | Missing confidence intervals. |
| 1.5 = Not reported | 1.10 = Yes | 2.2 = Yes | |||||
| 1.6 = NA | 1.11 = Yes | 2.3 = Yes | |||||
| Sánchez-Martín et al. [25] | 1.1 = Yes | 1.2 = Yes | 1.7 = Yes | 1.13 = No | 1.14 = No | 2.1 = Low | Both insufficient confounding assessment and missing confidence intervals. |
| 1.5 = Not reported | 1.10 = Yes | 2.2 = Yes | |||||
| 1.6 = NA | 1.11 = Yes | 2.3 = Yes | |||||
| Scarselli et al. [26] | 1.1 = Yes | 1.2 = Yes | 1.7 = Yes | 1.13 = Yes | 1.14 = No | 2.1 = Acceptable | Went from high to acceptable quality, because of missing confidence intervals. |
| 1.5 = 0% | 1.10 = Yes | 2.2 = Yes | |||||
| 1.6 = NA | 1.11 = Yes | 2.3 = Yes | |||||
| Shen et al. [27] | 1.1 = Yes | 1.2 = Yes | 1.7 = Yes | 1.13 = Yes | 1.14 = No | 2.1 = Acceptable | Went from high to acceptable quality, because of missing confidence intervals. |
| 1.5 = Not reported | 1.10 = Yes | 2.2 = Yes | |||||
| 1.6 = NA | 1.11 = Yes | 2.3 = Yes | |||||
| Gosálvez et al. [28] | 1.1 = Yes | 1.2 = Yes | 1.7 = Yes | 1.13 = Can’t say | 1.14 = No | 2.1 = Acceptable | Went from high to acceptable quality, because of missing confidence intervals. |
| 1.5 = Not reported | 1.10 = Yes | 2.2 = Yes | |||||
| 1.6 = NA | 1.11 = Yes | 2.3= Yes | |||||
| Jurema et al. [29] | 1.1 = Yes | 1.2 = Yes | 1.7 = Yes | 1.13 = Can’t say | 1.14 = No | 2.1 = Acceptable | Retrospective design. |
| 1.5 = NA retrospective | 1.10 = Yes | 2.2 = Yes | |||||
| 1.6 = NA | 1.11 = Yes | 2.3 = Yes | |||||
| Mayorga-Torres et al. [30] | 1.1 = Yes | 1.2 = Yes | 1.7 = Yes | 1.13 = Yes | 1.14 = No | 2.1 = Low | n = 6, therefore low quality. |
| 1.5 = 0% | 1.10 = Yes | 2.2 = No | |||||
| 1.6 = NA | 1.11 = Yes | 2.3 = Yes | |||||
| Jonge et al. [31] | 1.1 = Yes | 1.2 = Yes | 1.7 = Yes | 1.13 = Yes | 1.14 = No | 2.1 = Low | n = 11, therefore low quality. |
| 1.5 = 30% | 1.10 = Yes | 2.2 = No | |||||
| 1.6 = Yes | 1.11 = Can’t say | 2.3 = Yes | |||||
| Kulkarni et al. [32] | 1.1 = Yes | 1.2 = Yes | 1.7 = Yes | 1.13 = Yes | 1.14 = No | 2.1 = Acceptable | |
| 1.5 = not reported | 1.10 = Yes | 2.2 = Yes | |||||
| 1.6 = NA | 1.11 = Yes | 2.3 = Yes | |||||
| Marshburn et al. [33] | 1.1 = Yes | 1.2 = Yes | 1.7 = Yes | 1.13 = Can’t say | 1.14 = No | 2.1 = Acceptable | Retrospective design. |
| 1.5 = NA retrospective | 1.10 = Yes | 2.2 = Yes | |||||
| 1.6 = NA | 1.11 = Yes | 2.3 = Yes | |||||
| Barbagallo et al. [34] | 1.1 = Ýes | 1.2 = Can’t say | 1.7 = Yes | 1.13 = Yes | 1.14 = No | 2.1 = Acceptable | |
| 1.5 = Not reported | 1.10 = Yes | 2.2 = Yes | |||||
| 1.6 = NA | 1.11 = Yes | 2.3 = Yes | |||||
| Kably-Ambe et al. [35] | 1.1 = Yes | 1.2 = Yes | 1.7 = Yes | 1.13 = Can’t say | 1.14 = No | 2.1 = Acceptable | Retrospective design. |
| 1.5 = NA retrospective | 1.10 = Yes | 2.2 = Yes | |||||
| 1.6 = NA | 1.11 = Yes | 2.3 = Yes | |||||
| Gupta et al. [36] | 1.1 = Yes | 1.2 = Yes | 1.7 = Yes | 1.13 = Yes | 1.14 = Yes | 2.1 = Acceptable | High quality study but cannot rate higher than acceptable because of retrospective study design. |
| 1.5 = NA retrospective | 1.10 = Yes | 2.2 = Yes | |||||
| 1.6 = NA | 1.11 = Yes | 2.3 = Yes | |||||
| Manna et al. [37] | 1.1 = Yes | 1.2 = Yes | 1.7 = Yes | 1.13 = Yes | 1.14 = No | 2.1 = Acceptable | Went from high to acceptable quality, because of missing confidence intervals. |
| 1.5 = 1.5% | 1.10 = Yes | 2.2 = Yes | |||||
| 1.6 = NA | 1.11 = Yes | 2.3 = Yes | |||||
| Azizi et al. [38] | 1.1 = Yes | 1.2 = Yes | 1.7 = Yes | 1.13 = Yes | 1.14 = Yes | 2.1 = Acceptable | High quality study but cannot rate higher than acceptable because of retrospective study design. |
| 1.5 = NA retrospective | 1.10 = Yes | 2.2 = Yes | |||||
| 1.6 = NA | 1.11 = Yes | 2.3 = Yes | |||||
| Welliver et al. [39] | 1.1 = Yes | 1.2 = Yes | 1.7 = Yes | 1.13 = Can’t say | 1.14 = No | 2.1 = Acceptable | |
| 1.5 = 5% | 1.10 = Yes | 2.2 = Yes | |||||
| 1.6 = Can’t say | 1.11 = Yes | 2.3 = Yes | |||||
| Periyasamy et al. [40] | 1.1 = Yes | 1.2 = Yes | 1.7 = Yes | 1.13 = Yes | 1.14 = Yes | 2.1 = Acceptable | High quality study but cannot rate higher than acceptable because of retrospective study design. |
| 1.5 = NA retrospective | 1.10 = Yes | 2.2 = Yes | |||||
| 1.6 = NA | 1.11 = Yes | 2.3 = Yes | |||||
| Lee et al. [41] | 1.1 = Yes | 1.2 = Yes | 1.7 = Yes | 1.13 = Yes | 1.14 = No | 2.1 = Acceptable | Retrospective design. |
| 1.5 = NA retrospective | 1.10 = Yes | 2.2 = Yes | |||||
| 1.6 = NA | 1.11 = Yes | 2.3 = Yes |
NA: not applicable. Questions that were not relevant for our study were removed. In the selection section 1.3 and 1.4 were not applicable and in the assessment section 1.8, 1.9 and 1.12 were not applicable.