From: A review of reporting of participant recruitment and retention in RCTs in six major journals
 | Screened and eligible | Eligible and randomised | Randomised and outcome assessed | ||||||
---|---|---|---|---|---|---|---|---|---|
Factor & level | Median | IQR | Number of studies | Median | IQR | Number of studies | Median | IQR | Number of studies |
Study size | Â | Â | Â | Â | Â | Â | Â | Â | Â |
<200 | 78 | 63, 95 | 25 | 90 | 79, 100 | 26 | 92 | 86, 94 | 32 |
200–449 | 71 | 56, 95 | 18 | 93 | 78, 99 | 21 | 92 | 86, 99 | 29 |
450–749 | 51 | 33, 64 | 15 | 86 | 66, 97 | 15 | 93 | 84, 98 | 23 |
750+ | 71 | 41, 80 | 13 | 91 | 85, 100 | 13 | 97 | 89, 100 | 29 |
 |  |  | p = 0.026 |  |  | p = 0.99 |  |  | p = 0.24 |
Number of arms | Â | Â | Â | Â | Â | Â | Â | Â | Â |
2 | 72 | 48, 93 | 56 | 90 | 78, 100 | 59 | 94 | 88, 99 | 89 |
3+ | 68 | 51, 79 | 15 | 89 | 70, 97 | 16 | 86 | 76, 94 | 24 |
 |  |  | p = 0.33 |  |  | p = 0.75 |  |  | p = 0.0035 |
Multi-centre? | Â | Â | Â | Â | Â | Â | Â | Â | Â |
Yes | 75 | 42, 86 | 44 | 92 | 73, 99 | 47 | 94 | 85, 99 | 79 |
No | 64 | 50, 94 | 27 | 87 | 78, 100 | 28 | 93 | 88, 96 | 34 |
 |  |  | p = 0.91 |  |  | p = 0.70 |  |  | p = 0.64 |
Treatment focus | Â | Â | Â | Â | Â | Â | Â | Â | Â |
Drug | 71 | 53, 86 | 29 | 94 | 73, 100 | 30 | 94 | 86, 99 | 56 |
Surgery | 75 | 48, 99 | 10 | 89 | 63, 100 | 10 | 99 | 92, 100 | 17 |
Allied | 67 | 50, 88 | 17 | 91 | 81, 99 | 18 | 90 | 85, 94 | 18 |
Other | 64 | 44, 86 | 15 | 86 | 79, 93 | 17 | 92 | 84, 96 | 22 |
 |  |  | p = 0.89 |  |  | p = 0.56 |  |  | p = 0.014 |
Control | Â | Â | Â | Â | Â | Â | Â | Â | Â |
Active | 70 | 51, 86 | 30 | 88 | 74, 95 | 32 | 92 | 85, 98 | 52 |
Placebo | 68 | 49, 88 | 41 | 94 | 77, 100 | 43 | 93 | 86, 99 | 61 |
 |  |  | p = 0.82 |  |  | p = 0.24 |  |  | p = 0.46 |
Time to assessment | Â | Â | Â | Â | Â | Â | Â | Â | Â |
0 to 4 weeks | 8 | 33, 86 | 10 | 83 | 63, 94 | 11 | 99 | 93, 100 | 26 |
>4 weeks to 6 months | 7 | 51, 78 | 23 | 91 | 81, 100 | 24 | 92 | 87, 94 | 30 |
>6 to 18 months | 74 | 40, 93 | 20 | 94 | 72, 99 | 21 | 88 | 79, 98 | 31 |
>18 months | 75 | 63, 93 | 16 | 91 | 83, 100 | 16 | 95 | 86, 100 | 23 |
 |  |  | p = 0.087 |  |  | p = 0.242 |  |  | p = 0.075 |
Funding | Â | Â | Â | Â | Â | Â | Â | Â | Â |
Pharma | 74 | 54, 93 | 28 | 94 | 83, 100 | 29 | 93 | 85, 99 | 56 |
Government/charity | 67 | 48, 86 | 38 | 85 | 70, 97 | 40 | 93 | 86, 96 | 49 |
Internal/unstated | 56 | 51, 56 | 5 | 98 | 94, 100 | 6 | 95 | 91, 100 | 8 |
 |  |  | p = 0.51 |  |  | p = 0.048 |  |  | P = 0.50 |