Table 2 Prevalence of registration among published randomized trials according to trial size
From: Registration of published randomized trials: a systematic review and meta-analysis
Reference | Sample size | Number of trials | Number of registered trials | Proportion of registered trials (95% CI) | p value* |
|---|---|---|---|---|---|
Jones [48] | < 100 | 48 | 17 | 0.35 (0.22; 0.51) | 0.009 |
100–199 | 36 | 14 | 0.39 (0.23; 0.57) | ||
200–499 | 30 | 21 | 0.70 (0.51; 0.85) | ||
≥ 500 | 9 | 5 | 0.56 (0.21; 0.86) | ||
Mann [53] | < 100 | 71 | 33 | 0.46 (0.35; 0.59) | 0.0009 |
100–499 | 117 | 83 | 0.71 (0.62; 0.79) | ||
500–999 | 13 | 10 | 0.77 (0.46; 0.95) | ||
≥ 1000 | 15 | 12 | 0.80 (0.52; 0.96) | ||
McGee [54] | < 200 | 235 | 40 | 0.17 (0.12; 0.22) | < 0.0001 |
≥ 200 | 72 | 34 | 0.47 (0.35; 0.59) | ||
Pinto [61] | ≤ 25 | 34 | 5 | 0.15 (0.05; 0.31) | < 0.0001 |
26–50 | 53 | 13 | 0.25 (0.14; 0.38) | ||
51–100 | 61 | 19 | 0.31 (0.20; 0.44) | ||
101–499 | 42 | 23 | 0.55 (0.39; 0.70) | ||
≥ 500 | 10 | 7 | 0.70 (0.35; 0.93) | ||
Reveiz [62] | ≤ 100 | 442 | 59 | 0.13 (0.10; 0.17) | < 0.0001 |
> 100 | 84 | 30 | 0.36 (0.26; 0.47) |