Table 1 Characteristics of included articles by registration status (n = 137)
| Characteristic |
Prior registration N = 54 |
No Prior Registration N = 83 |
|---|---|---|
| Publication characteristics | ||
| Peer reviewed | 53 (98%) | 76 (92%) |
| Year of publication | ||
| 1996-2002 | 0 (0%) | 29 (35%) |
| 2003-2004 | 12 (22%) | 28 (34%) |
| 2005-2006 | 14 (26%) | 19 (23%) |
| 2007-2008 | 28 (52%) | 7 (8%) |
| Impact factor, median (interquartile range)* | 15.5 (10.9-34.8) | 5.8 (4.0-10.5) |
| First or main report | 45 (83%) | 70 (84%) |
| Study design characteristics | ||
| Comparison group | ||
| Placebo | 40 (74%) | 32 (39%) |
| Active treatment only | 14 (26%) | 51 (62%) |
| Non-inferiority trial - Yes | 2 (4%) | 9 (11%) |
| Primary efficacy outcome = survival | 21 (39%) | 9 (11%) |
| Stringent blinding (2/3 points) | 16 (30%) | 20 (24%) |
| Sample size, median (interquartile range) | 696 (150-923) | 283 (99-565) |
| Statistical significance of primary outcome | ||
| Favorable to test drug | 36 (67%) | 44 (53%) |
| Inconclusive | 18 (33%) | 37 (45%) |
| Unfavorable | 0 (%) | 2 (2%) |
| Conclusion | ||
| Favorable to test drug | 43 (80%) | 55 (66%) |
| About equal | 10 (18%) | 22 (27%) |
| Unfavorable | 1 (2%) | 6 (7%) |
| Sponsored by test drug maker | 47 (87%) | 62 (75%) |