Table 2 Summary characteristics of trials in the three registries
Description | ISRCTN, N (%) | CTG, N (%) | PACTR, N (%) |
|---|---|---|---|
Number of trials registered | 507 | 2622 | 1501 |
Number of studies completed | 386 (76.1) | 1469 (56.0) | - |
Number of completed with results | 224 (44.2) | 243 (9.3) | 40 (2.6) |
Overall trial status | |||
Completed | 386 (76.1) | 1469 (56.0) | - |
Ongoing/active | 103 (20.3) | 278 (10.6) | - |
Not yet recruiting/pending | 15 (3.0) | 147 (5.6) | 443 (29.5) |
Recruiting | 49 (9.7) | 429 (16.4) | 324 (21.6) |
Stopped/terminated | 2 (0.4) | 65 (2.5) | - |
Suspended | 16 (3.2) | 18 (0.7) | - |
Withdrawn | - | 34 (1.3) | - |
Other/unknown | - | 183 (7.0) | - |
Prospective/retrospective | |||
Prospectively registered | 228 (45.0) | - | - |
Retrospectively registered | 279 (55.0) | - | - |
Study design | |||
Allocation | |||
Randomised | 450 (88.8) | 2090 (79.7) | 1319 (87.9) |
Non-randomised | 50 (9.9) | 224 (8.5) | 175 (11.7) |
N/A | 3 (0.6) | 300 (11.4) | 7 (0.5) |
Intervention model | |||
Parallel assignment | - | 1919 (73.2) | 1003 (66.8) |
Single group assignment | - | 414 (15.8) | 49 (3.3) |
Cross-over assignment | - | 113 (4.3) | 95 (6.3) |
Factorial assignment | - | 107 (4.1) | 341 (22.9) |
Sequential assignment | - | 60 (2.3) | - |
None (open label) | - | 7 (0.3) | - |
Masking | |||
None | - | 1577 (60.1) | - |
Single | - | 348 (13.3) | - |
Double | - | 224 (8.5) | - |
Triple | - | 146 (5.6) | - |
Quadruple | - | 312 (11.9) | - |
Phase | |||
Not applicable | 149 (29.4) | 1426 (54.4) | 1301 (86.7) |
Not specified | 10 (2.0) | ||
Phase 0/early phase 1 | - | 11 (0.4) | 43 (2.9) |
Phase I | 4 (0.8) | 169 (6.4) | 43 (2.9) |
Phase I/II | 3 (0.6) | 109 (4.2) | |
Phase II | 27 (5.3) | 371 (14.1) | 52 (3.5) |
Phase II/III | 10 (2.0) | 113 (4.3) | |
Phase III | 57 (11.2) | 423 (16.1) | 60 (4.0) |
Phase III/IV | 2 (0.4) | ||
Sponsor | |||
University | 262 (51.7) | 1618 (61.7) | 496 (33.3) |
Industry/INGOa | 16 (3.2) | 288 (11.0) | 27 (1.8) |
Research institution | 105 (20.7) | 1190 (45.4) | 164 (10.9) |
Government | 56 (11.0) | ||
Charity | 38 (7.5) | ||
Hospital/clinic | 16 (3.2) | 437 (16.7) | 94 (6.3) |
Private individuals | 116 (7.7) | ||
Sex | |||
Both | 413 (81.5) | 1961 (74.8) | 1074 (71.6) |
Female | 88 (17.4) | 553 (21.1) | 360 (24.0) |
Male | 5 (1.0) | 108 (4.1) | 67 (4.5) |
Target number of participants | |||
Min, maxa | 0, 2,000,000 | 0, 650,000 | 0, 497,379 |
Mean (SD)a | 73,780 (338,098) | 5298 (32,513) | 1322 (15,010) |
Median (IQR)a | 902 (2,004,000) | 348 (1,001,233) | 140 (60,400) |