- Quality evaluation of the included articles using the Newcastle-Ottawa scale.
| Authors | Types of study | Research object selection (0-4) | Intergroup comparability (0-2) | Outcome indicators (0-3) | Total (0-9) |
|---|---|---|---|---|---|
| Lin et al16 | Retrospective | **** | ** | * | 7 |
| Lee et al17 | Retrospective | **** | ** | * | 7 |
| Kitamura et al18 | Retrospective | **** | ** | * | 7 |
| Kitamura et al19 | Retrospective | **** | ** | * | 7 |
| Harada et al20 | Retrospective | **** | ** | * | 7 |
One star for each point, maximum of 9 stars.