TABLE 2.
Characteristics of Completed and Discontinued RCTs
| All Trials (n = 559), n (%) | Completed Trials (n = 455), n (%) | Discontinued Trials (n = 104), n (%) | P | |
|---|---|---|---|---|
| Intervention | .81 | |||
| Behavioral | 55 (9.8) | 47 (10) | 8 (7.7) | |
| Drug/Biologic | 379 (67.8) | 304 (66.8) | 75 (72.1) | |
| Device/Procedure | 37 (6.6) | 32 (7.0) | 5 (4.8) | |
| Dietary supplement | 45 (8.1) | 37 (8.1) | 8 (7.7) | |
| Other | 43 (7.7) | 35 (7.7) | 8 (7.7) | |
| Age of study participants | .60 | |||
| Preterm, newborn, and infant | 145 (25.9) | 119 (26.2) | 26 (25.0) | |
| Toddler and preschool | 119 (21.3) | 101 (22.2) | 18 (17.3) | |
| School age | 68 (12.2) | 57 (12.5) | 11 (10.6) | |
| Adolescent | 60 (10.7) | 46 (10.1) | 14 (13.5) | |
| Mixed ages | 167 (29.9) | 132 (29.0) | 35 (33.7) | |
| Primary funding source | .044 | |||
| Academic institution | 245 (43.8) | 188 (41.3) | 57 (54.8) | |
| Industry | 272 (48.7) | 231 (50.8) | 41 (39.4) | |
| Other | 42 (7.5) | 36 (7.9) | 6 (5.8) | |
| Year registered | .84 | |||
| 2008 | 199 (35.6) | 161 (35.4) | 38 (36.5) | |
| 2009 | 202 (36.1) | 163 (35.8) | 39 (37.5) | |
| 2010 | 158 (28.3) | 131 (28.8) | 27 (26.0) | |
| Trial phasea | .16 | |||
| Phase 1 | 29 (5.2) | 26 (5.7) | 3 (2.9) | |
| Phase 2 | 115 (20.6) | 89 (19.6) | 26 (25.0) | |
| Phase 3 | 186 (33.3) | 159 (35.0) | 27 (26.0) | |
| Phase 4 | 81 (14.5) | 61 (13.4) | 20 (19.2) | |
| Unknown | 148 (26.5) | 120 (26.4) | 28 (26.9) | |
| Masking | .22 | |||
| Open label | 187 (33.5) | 155 (34.1) | 32 (30.8) | |
| Single blind | 77 (13.8) | 67 (14.7) | 10 (9.6) | |
| Double bind | 295 (52.8) | 233 (51.2) | 62 (59.6) | |
| Planned sample size | <.001 | |||
| <100 participants | 212 (37.9) | 161 (35.4) | 51 (49.0) | |
| 100–499 participants | 227 (40.6) | 182 (40.0) | 45 (43.3) | |
| >500 participants | 120 (21.5) | 112 (24.6) | 8 (7.7) |
a
Phase 0 trials (n = 5) included as phase 1. Trials described as phase 1/2 (n = 17) were categorized as phase 2, and trials described as phase 2/3 (n = 18) were categorized as phase 3.