Characteristics | Categories | Trials with significant results reported (N = 844) | Trials with non statistically significant results or no treatment effect estimate or p-value reported (N = 1979) | p-value |
---|---|---|---|---|
Phase of the study | Phase 3 | 622 (74) | 1054 (53) | <0.0001 |
Phase 4 | 222 (26) | 925 (47) | ||
Intervention type | Drug | 675 (80) | 1427 (72) | <0.0001 |
Mixed interventions | 97 (11) | 231 (12) | ||
Biological | 29 (3) | 115 (6) | ||
Device | 22 (3) | 115 (6) | ||
Other | 21 (2) | 91 (5) | ||
Control group | Placebo or no treatment | 543 (64) | 795 (40) | <0.0001 |
Active treatment | 301 (36) | 1184 (60) | ||
Sponsorship | Industry totally or partly | 744 (88) | 1473 (74) | <0.0001 |
Academic only | 100 (12) | 506 (26) | ||
Countries | Single country | 361 (43) | 1267 (64) | <0.0001 |
Multiple countries | 353 (42) | 507 (26) | ||
Not reported | 130 (15) | 205 (10) | ||
Location | At least one site in the USA | 493 (59) | 1175 (59) | 0.003 |
No site in the USA | 221 (26) | 599 (30) | ||
Not reported | 130 (15) | 205 (10) | ||
Subject to the FDAAA | Yes | 588 (70) | 1206 (61) | <0.0001 |
No | 201 (24) | 732 (37) | ||
Not reported | 55 (6) | 41 (2) | ||
Centers | Multicenter | 581 (69) | 1044 (53) | <0.0001 |
Single center | 133 (16) | 730 (37) | ||
Not reported | 130 (15) | 205 (10) | ||
Sample size | Median (Q1-Q3) | 305 (139–541) | 179 (62–405) | <0.0001 |
Time to results first received at ClinicalTrials.gov (month) | Median (Q1-Q3) | 13.0 (11.6–26.3) | 16.5 (12.0–30.9) | <0.0001 |