TABLE 5.
Characteristics of Published and Unpublished RCTs 24 and 36 Months After Trial Completion
| Published at 24 mo (n = 262), n (%) | Unpublished at 24 mo (n = 193), n (%) | P | Published at 36 moa (n = 354), n (%) | Unpublished at 36 moa (n = 95), n (%) | P | |
|---|---|---|---|---|---|---|
| Intervention | .01 | .11 | ||||
| Behavioral | 34 (13.0) | 13 (6.7) | 41 (11.6) | 5 (5.3) | ||
| Drug/biologic | 159 (60.7) | 145 (75.1) | 226 (63.8) | 73 (76.8) | ||
| Device/procedure | 24 (9.2) | 8 (4.2) | 29 (8.2) | 3 (3.2) | ||
| Dietary supplement | 23 (8.8) | 14 (7.3) | 30 (8.5) | 7 (7.4) | ||
| Other | 22 (8.4) | 13 (6.7) | 28 (7.9) | 7 (7.4) | ||
| Age of study participants | .60 | .64 | ||||
| Preterm, newborn, and infant | 67 (25.6) | 52 (26.9) | 87 (24.6) | 31 (32.6) | ||
| Toddler and preschool | 64 (24.4) | 37 (19.2) | 80 (22.6) | 19 (20.0) | ||
| School age | 34 (13.0) | 23 (11.9) | 46 (13.0) | 11 (11.6) | ||
| Adolescent | 23 (8.8) | 23 (11.9) | 37 (10.5) | 9 (9.5) | ||
| Mixed ages | 74 (28.2) | 58 (30.1) | 104 (29.4) | 25 (26.3) | ||
| Primary funding source | <.001 | <.001 | ||||
| Academic institution | 130 (49.6) | 58 (30.1) | 164 (46.3) | 22 (23.2) | ||
| Industry | 110 (42.0) | 121 (62.7) | 162 (45.8) | 66 (69.5) | ||
| Other | 22 (8.4) | 14 (7.3) | 28 (7.9) | 7 (7.4) | ||
| Trial phaseb | .16 | .06 | ||||
| Phase 1 | 14 (5.3) | 12 (6.2) | 18 (5.1) | 7 (7.4) | ||
| Phase 2 | 53 (20.2) | 36 (18.7) | 67 (18.9) | 20 (21.1) | ||
| Phase 3 | 81 (30.9) | 78 (40.4) | 120 (33.9) | 38 (40.0) | ||
| Phase 4 | 35 (13.4) | 26 (13.5) | 44 (12.4) | 16 (16.8) | ||
| Unknown | 79 (30.2) | 41 (21.2) | 105 (29.7) | 14 (3.1) | ||
| Masking | .29 | .19 | ||||
| Open label | 94 (35.9) | 61 (31.6) | 124 (35.0) | 29 (30.5) | ||
| Single blind | 42 (16.0) | 25 (13.0) | 56 (15.8) | 10 (10.5) | ||
| Double blind | 126 (48.1) | 107 (55.4) | 174 (49.2) | 56 (59.0) | ||
| Actual sample size | .07 | .64 | ||||
| <100 participants | 109 (41.6) | 60 (31.1) | 134 (37.9) | 32 (33.7) | ||
| 100–499 participants | 96 (36.6) | 85 (44.0) | 138 (39.0) | 42 (44.2) | ||
| >500 participants | 57 (21.8) | 48 (24.9) | 82 (23.2) | 21 (22.1) |
a
Six trials were excluded from this analysis because 36 mo had not elapsed between completion date and time that publication search was conducted.
b
Phase 0 trials (n = 5) were included as Phase 1. Trials described as phase 1/2 (n = 15) were categorized as phase 2, and trials described as phase 2/3 (n = 15) were categorized as phase 3.