Table 3 Quality assessment using the Newcastle–Ottawa quality assessment scale for each non-randomized controlled trial
Variable | Lan et al. [7] | Vaishnav et al. [8] | Wei et al. [11] | He et al. [16] | Noh et al. [17] | Lee et al. [18] | Son et al. [19] | Wang et al. [21] | Wang et al. [23] | Yan et al. [24] | Li et al. [25] | Shao et al. [27] | Yi et al. [28] | Wang et al. [29] | Sun et al. [31] | Hu et al. [32] | Sha et al. [33] | Chang et al. [9] | Ruan et al. [34] | Zhu et al. [35] | Zhang et al. [36] | Gou et al. [10] | Luo et al. [37] |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Selection | |||||||||||||||||||||||
Representativeness of exposed cohort | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
Selection of non-exposed cohort | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
Ascertainment of exposure | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
Demonstration that outcome of interest was not present at start of study | 1 | 1 | 1 | 1 | 1 | 1 | |||||||||||||||||
Comparability | |||||||||||||||||||||||
Study controlled for age or gender | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
Study controlled for any additional factor | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | ||
Outcome | |||||||||||||||||||||||
Assessment of outcome | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
Follow-up long enough for outcomes to occur | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
Adequacy of follow-up of cohort | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |||||
Total | 8 | 8 | 9 | 8 | 7 | 7 | 8 | 8 | 8 | 8 | 8 | 9 | 9 | 6 | 8 | 8 | 7 | 8 | 8 | 9 | 8 | 8 | 8 |