Table 3.
Designs of 61 observational trials registered on ClinicalTrial.gov.
| Characteristics | Number | Percentage (%) | |
|---|---|---|---|
| Observational model | |||
| Case-control | 8 | 13.11 | |
| Case-only | 9 | 14.75 | |
| Case-crossover | 1 | 1.64 | |
| Cohort | 35 | 57.38 | |
| Other | 6 | 9.84 | |
| Unknown | 2 | 3.28 | |
| Time perspective | |||
| Prospective | 42 | 68.85 | |
| Retrospective | 14 | 22.95 | |
| Cross-sectional | 2 | 3.28 | |
| Other | 2 | 3.28 | |
| Unknown | 1 | 1.64 | |
| Enrollment | |||
| 0–100 | 14 | 22.95 | |
| 100–500 | 25 | 40.98 | |
| >500 | 21 | 34.43 | |
| Unknown | 1 | 1.64 | |
| Participant gender | |||
| Female only | 2 | 3.28 | |
| Both | 59 | 96.72 | |
| Participant age (year) | |||
| <18 | 3 | 4.92 | |
| ≥18 | 49 | 80.33 | |
| Both | 9 | 14.75 | |
| Status | |||
| Not recruiting | 14 | 22.95 | |
| Recruiting | 15 | 24.59 | |
| Completed | 23 | 37.70 | |
| Terminated/withdrawn | 3 | 4.92 | |
| Unknown | 6 | 9.84 | |
| Results | |||
| Has results | 0 | 0.00 | |
| No results available | 61 | 100.00 | |
| Sponsor | |||
| University | 20 | 32.79 | |
| Hospital | 27 | 44.26 | |
| Industry/company | 6 | 9.84 | |
| Other | 8 | 13.11 | |
| Funding source | |||
| Industry | 7 | 11.48 | |
| Other | 54 | 88.52 | |
| Location | |||
| America | 16 | 26.23 | |
| Europe | 30 | 49.18 | |
| Asia | 5 | 8.20 | |
| Unknown | 10 | 16.39 | |