Table 2.
Quality assessment of individual study
| Study | Allocation sequence generation | Allocation concealment | Blinding | Loss to follow‐up | Calculation of sample size | Statistical analysis | Intention‐to‐treat analysis | Level of quality |
|---|---|---|---|---|---|---|---|---|
| Itoh et al. 21 | A | B | B | 0 | Yes | Student's t‐test or Mann–Whitney U‐test and the χ2 test | Yes | B |
| Rathi et al. 23 | A | A | A | 0 | Yes | Student's t‐test or Mann–Whitney U‐test and the χ2 test | Yes | A |
| Kumar et al. 5 | A | A | A | 6 | Yes | Bonferroni or Kruskal–Wallis test, and Mann–Whitney U test | Yes | A |
| Imperatore et al. 20 | A | A | B | 0 | Yes | Student's t‐test and the χ2 test | Yes | B |
| Itoh et al. 22 | A | B | B | 0 | Yes | Student's t‐test or Mann–Whitney U‐test and χ2 test | Yes | B |
| Gupta et al. [24] | A | A | A | 0 | Yes | Student's t‐test and χ2 test | Yes | A |
| Sur et al. 25 | A | A | A | 6 | Yes | Logistic regression, or Wilcoxon test and Kaplan–Meier analysis | Yes | A |
| Dell'Atti et al. 26 | A | B | A | 0 | Yes | Mann–Whitney and the Wilcoxon tests, or χ2 test | Yes | B |
A all quality criteria met (adequate): low risk of bias. B one or more of the quality criteria only partly met (unclear): moderate risk of bias.
C one or more criteria not met (inadequate or not used): high risk of bias.