Table 2.
Quality assessment of six cross-sectional studies.
| Chan et al. (27) | Liu et al. (28) | Tajima et al. (23) | Kim and Shin (25) | Li et al. (33) | Du et al. (31) | |
|---|---|---|---|---|---|---|
| Define the source of information (survey, record review) | 1 | 1 | 1 | 1 | 1 | 1 |
| List inclusion and exclusion criteria for exposed and unexposed subjects (cases and controls) or refer to previous publications. | 1 | 1 | 1 | 1 | 1 | 1 |
| Indicate time period used for identifying patients. | 1 | 1 | 1 | 1 | 1 | 1 |
| Indicate whether or not subjects were consecutive if not population-based. | 1 | 1 | 1 | 1 | 1 | 1 |
| Indicate if evaluators of subjective components of study were masked to other aspects of the status of the participants. | 1 | 1 | 1 | 1 | 1 | 1 |
| Describe any assessments undertaken for quality assurance purposes (e.g., test/retest of primary outcome measurements). | 1 | 1 | 1 | 1 | 1 | 1 |
| Explain any patient exclusions from analysis. | 0 | 0 | 0 | 0 | 0 | 0 |
| Describe how confounding was assessed and/or controlled. | 1 | 1 | 1 | 1 | 1 | 1 |
| If applicable, explain how missing data were handled in the analysis. | 1 | 1 | 1 | 1 | 1 | 1 |
| Summarize patient response rates and completeness of data collection. | 1 | 1 | 1 | 1 | 1 | 1 |
| Clarify what follow-up, if any, was expected and the percentage of patients for which incomplete data or follow-up was obtained. | 1 | 1 | 1 | 1 | 1 | 1 |
| Total score | 10 | 10 | 10 | 10 | 10 | 10 |