Table 7.
Comparison of the current review with three previous reviews in terms of successful recruitment to target sample size and extensions to recruitment
| Review | McDonald et al7 | Sully et al5 | Walters et al8 | This study | This study |
| Recruitment period | 1994–2002 | 2002–2008 | 2004–2016 | 2017–2020 | 1997–2020 |
| No of trials in the study | N=122 | N=73 | N=151 | N=174 | N=388 |
| Recruited 100% of original target | 38 of 122 (31%) | 40 of 73 (55%) | 61 of 151 (40%) | 107 of 174 (61%) | 207 of 388 (53%) |
| Original target was revised | 42 of 122 (34%) | 14 of 73 (19%) | 52 of 151 (34%) | 54 of 174 (31%) | 118 of 388 (30%) |
| Original target revised upward | 6 of 42 (14%) | 5 of 14 (36%) | 11 of 52 (21%) | 23 of 54 (43%) | 39 of 118 (33%) |
| Original target revised downward | 36 of 42 (86%) | 9 of 14 (64%) | 41 of 52 (79%) | 31 of 54 (57%) | 79 of 118 (67%) |
| Recruited 80% of original target | 67 of 122 (55%) | 57 of 73 (78%) | 95 of 151 (63%) | 139 of 174 (80%) | 288 of 388 (74%) |
| Recruited 100% of revised target | 19 of 42 (45%) | 10 of 14 (71%) | 28 of 52 (54%) | 35 of 54 (65%) | 80 of 118 (68%) |
| Recruited 80% of revised target | 34 of 42 (80%) | 13 of 14 (93%) | 48 of 52 (92%) | 48 of 54 (89%) | 107 of 118 (91%) |
| Extended their recruitment | 65 of 122 (54%) | 33 of 73 (45%) | 49 of 151 (32%) | 65 of 174 (37%) | 128 of 388 (33%) |