Table 2.
A modified Newcastle-Ottawa scale for quality assessment of included studies.
| Study | Selection (0–1) |
Comparabilitya (0–2) |
Outcome (0–1) |
Total (7) | ||||
|---|---|---|---|---|---|---|---|---|
| Representativeness of exposed cohort | Selection of non-exposed cohort | Ascertainment of exposure | Comparability of cohorts on the basis of the design or analysis | Assessment of outcome | Adequate of follow-up | |||
| Chen SJ 2013 | 1 | 1 | 1 | 2 | 1 | 1 | 7 | |
| Chen DY, et al. (2016) | 0 | 1 | 0 | 2 | 0 | 1 | 4 | |
| Im SI, et al. (2018) | 1 | 1 | 0 | 1 | 0 | 0 | 3 | |
| Chang Y, et al. (2020) | 1 | 1 | 1 | 0 | 1 | 1 | 5 | |
| Sen S, et al. (2021) | 1 | 1 | 1 | 2 | 1 | 1 | 7 | |
a
Comparability were assessed as followed: 1 point when the exposed subjects were matched with non-exposed subjects, 2 points if the study also adjusted for age, sex, and comorbidities.