Table 4.
Trial participant, intervention, and other descriptors in registry (Data source: ClinicalTrials.gov, N = 1988).
| Item | N (%) |
|---|---|
| Participant Sex | |
| Female only | 225 (11.3%) |
| Male only | 29 (1.5%) |
| Both | 1730 (87%) |
| Missing | 4 (0.2%) |
| Participant Age * | |
| Children (< 18) only | 268 (13.5%) |
| Senior (65+) only | 72 (3.6%) |
| Mixed ages | 1617 (81.3%) |
| Missing | 31 (1.6%) |
| Phase (categories as in ClinicalTrials.gov) | |
| Early Phase 1 | 12 (0.6%) |
| Phase 1 | 9 (0.5%) |
| Phase 1/Phase 2 | 15 (0.8%) |
| Phase 2 | 63 (3.2%) |
| Phase 2/Phase 3 | 38 (1.9%) |
| Phase 3 | 208 (10.5%) |
| Phase 4 | 244 (12.3%) |
| Phase N/A | 1368 (68.8%) |
| Missing | 31 (1.6%) |
| Type of intervention (categories as in ClinicalTrials.gov)Ψ | |
| Behavioral | 903 (45.4%) |
| Biological | 41 (2.1%) |
| Device | 155 (7.8%) |
| Dietary | 53 (2.7%) |
| Drug | 324 (16.3%) |
| Procedure | 128 (6.4%) |
| Radiation | 10 (0.5%) |
| Other | 635 (31.9%) |
| Missing | 14 (0.7%) |
| Primary purpose (categories as in ClinicalTrials.gov) | |
| Treatment | 746 (37.5%) |
| Prevention | 500 (25.2%) |
| Health Services Research | 342 (17.2%) |
| Supportive Care | 158 (7.9%) |
| Screening | 53 (2.7%) |
| Basic Science | 8 (0.4%) |
| Diagnostic | 66 (3.3%) |
| Education/Counseling | 1 (0.1%) |
| Other | 38 (1.9%) |
| Missing | 76 (3.8%) |
| Number of primary outcomes | |
| Min, Max | 1, 20 |
| Median (Q1–Q3) | 1 (1–1) |
| Mean (SD) | 1.46 (1.21) |
| 1 | 1516 (76.2%) |
| 2 | 279 (14%) |
| 3 or more | 186 (9.4%) |
| Missing | 7 (0.4%) |
| Masking | |
| None | 1005 (50.6%) |
| Single | 588 (29.5%) |
| Double | 172 (8.6%) |
| Triple | 72 (3.6%) |
| Quadruple | 106 (5.3%) |
| Missing | 45 (2.3%) |
| Number of facilities | |
| Min, Max | 1, 916 |
| Median (Q1–Q3) | 1 (1–2) |
| Mean (SD) | 8.6 (45.4) |
| 1 | 1203 (61%) |
| > 1 | 619 (31.1%) |
| Missing | 166 (8.4%) |
*
Using the minimum and maximum ages a potential participant must be to be eligible for the study, we established whether a trial solely involved children or infants (applying an upper threshold of 18 years using the maximum age category, and applying no minimum threshold), an older population (applying a lower threshold of 65 years using the minimum listed age for participants and no maximum age limit), or included a mix of ages.
Ψ
Does not sum to 100% as trials may have multiple interventions.