Table 1. Comparison of characteristics of registered protocols in ClinicalTrials.gov a and IRCT .
| Characteristics | ClinicalTrials.gov ( N=119,840) | IRCT ( N=1751) | P-value | |
| Randomization | <0.001 b | |||
| Non-randomized | 41266 (34.4%) | 44 (2.5%) | ||
| Randomized | 74313 (62.0%) | 1541 (88%) | ||
| N/A | 0 | 166 (9.5%) | ||
| Allocation missing | 4261 (3.6%) | 0 | ||
| Blinding | <0.001 b | |||
| Open label | 64222 (53.6%) | 578 (33%) | ||
| Single blind | 6383 (5.3%) | 322 (18.4%) | ||
| Double blind | 45094 (37.6%) | 753 (43%) | ||
| Triple blind | 0 | 98 (5.6%) | ||
| Masking missing | 4141 (3.5%) | 0 | ||
| Study centers | <0.001 b | |||
| Multi-center | 44775 (37.4%) | 212 (12.1%) | ||
| Single-center | 75065 (62.6%) | 1539 (87.9%) | ||
| Median sample size (IQR) f | 60 (26-157) | 66 (45-100) | <0.001 b | |
| <100 | 74780 (62.4%) | 1247 (71.2%) | ||
| ≥100 | 45059 (37.6%) | 485 (27.7%) | ||
| Study duration (days) Median (IQR) f | 701.0 (335-1,218) | 177.5 (90-364) | - | |
| Funding: f | <0.001 b | |||
| Industry | 62556 (52.2%) | 37 (2.1%) | ||
| Public | 13541 (11.3%) | 1529 (87.3%) | ||
| Others | 43741 (36.5%) | 185 (10.6%) | ||
| Purpose | <0.001 b | |||
| Treatment | 94074 (78.5%) | 1022 (58.4%) | ||
| Prevention | 10306 (8.6%) | 360 (20.6%) | ||
| Number of study groups | <0.001 b | |||
| Single group | 42902 (35.8%) | 146 (8.3%) | ||
| Controlled group | 76937 (64.2%) | 1605 (91.7%) | ||
| Phase II-IV trials published in scientific journal | 8338 (29.9%) d | 160 (47.7%) e | - | |
| Scientometric measures | ||||
| CiteScore | 3.01 (2.28-4.46) | 1.44 (0.88-2.22) | <0.001 c | |
| SNIP | 1.32 (0.98-2) | 0.83 (0.59-1.01) | <0.001c | |
| SJR | 1.67 (1.1-3.23) | 0.58 (0.34-0.91) | <0.001c |
aData is reported by Magdalena Zwierzyna et alb P-values are calculated using chi squared test; cP-values are calculated using Mann-Whitney U test; d Of 27835 phase II-IV registered protocols in ClinicalTrials.gov; e Of 335 phase II-IV of registered protocols in IRCT; fmissing values are less than 1.5% in IRCT