Table 2.
Quality assessment based on the Newcastle–Ottawa scale.
| Study | Representativeness of the patient | Selection of the controls | Ascertainment Of intervention | Demonstration that outcome of interest was not present at the start of the study | Comparability-age and gender | Comparability-Other factors | Assessment of outcome | Was follow-up long enough for outcomes to occur | Adequacy of follow-up of cohorts | Total |
|---|---|---|---|---|---|---|---|---|---|---|
| 1. Hua et al. (17) | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 8 |
| 2. Molina-Lerma et al. (18) | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 8 |
| 3. Qian et al. (19) | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 9 |
| 4. Sheng et al. (20) | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 8 |
| 5. Vijayaraman (21) | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 9 |
| 6. Wu (22) | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 9 |
| 7. Hou et al. (15) | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 9 |
Average score: 8.57.