Table 2 Quality Assessment Using the Newcastle–Ottawa Quality Assessment Scale for Each Non-Randomized Controlled Trial
Variable | Heo [15] | Kim [21] | Kang [8] | Gatam [16] | Zhu [14] | Ni [20] | Jiang [19] | Song [12] | Kong [11] | Song [9] | Huang [10] | Heo [17] | Yu [18] | Yang [13] |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Selection | ||||||||||||||
Representativeness of exposed cohort | 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 |
Ascertainment of exposure | 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 | Â | Â | 1 | Â | Â | 1 | 1 | Â | Â | 1 | 1 | 1 | Â |
Comparability | ||||||||||||||
Study controlled for age or gender | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
Study controlled for any additional factor | 1 | 1 | 1 | Â | Â | Â | Â | 1 | 1 | 1 | Â | 1 | Â | 1 |
Outcome | ||||||||||||||
Assessment of outcome | 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 |
Adequacy of follow-up of cohort | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
Total | 9 | 8 | 8 | 8 | 7 | 7 | 8 | 9 | 8 | 8 | 8 | 9 | 8 | 8 |