Table 1 Trial characteristics
Trials included in the review (N = 30) | ||
|---|---|---|
n/N | % | |
Interim analysis details | ||
Number of interim analyses planned | ||
1 | 28/30 | 93.3 |
2 | 2/30 | 6.7 |
Timing of the first interim analysis1 (% of initially planned sample size) | ||
Median (IQR) | 60.0 | (41.1, 72.6) |
Status of information at the first interim analysis | ||
Completed data collection (primary outcome) | 14/23 | 60.9 |
Recruited | 5/23 | 21.7 |
Events occurred | 4/23 | 17.4 |
Result at first interim analysis | ||
Continue | 4/13 | 30.8 |
Stop | 2/13 | 15.4 |
SSR | 7/13 | 53.8 |
Maximum sample size percentage increase2 | ||
Median (IQR) | 50.0 | (35.3, 100.0) |
Actual sample size percentage increase3 | ||
Median (IQR) | 11.56 | (1.12, 42.3) |
Stopping boundaries?4 | ||
Yes | 15/21 | 71.4 |
If yes, type of stopping boundary | ||
Efficacy | 4/15 | 26.7 |
Futility | 5/15 | 33.3 |
Efficacy and futility | 4/15 | 26.7 |
Not specified | 2/15 | 13.3 |
General trial characteristics | ||
Primary outcome type | ||
Binary | 16/33 | 48.5 |
Continuous | 10/33 | 30.3 |
Time-to-event | 7/33 | 21.2 |
Time to primary outcome | ||
0–3 days | 5/30 | 16.7 |
1–6 weeks | 6/30 | 20.0 |
8–12 weeks | 6/30 | 20.0 |
5–6 months | 4/30 | 13.3 |
1–5 years | 9/30 | 30.0 |
Number of groups | ||
2 | 29/30 | 96.7 |
4 | 1/30 | 3.3 |
Study design | ||
Cluster | 1/30 | 3.3 |
Crossover | 1/30 | 3.3 |
Parallel group | 28/30 | 93.3 |
Phase6 | ||
I | 1/20 | 5.0 |
II | 6/20 | 30.0 |
III | 13/20 | 65.0 |
Disease area | ||
Cardiovascular | 5/30 | 16.7 |
Diabetes | 4/30 | 13.3 |
Neurology | 7/30 | 23.3 |
Oncology | 5/30 | 16.7 |
GI | 2/30 | 6.7 |
Others**** | 7/30 | 23.3 |
Progress | ||
In progress | 12/30 | 40.0 |
In analysis | 3/30 | 10.0 |
Completed | 15/30 | 50.0 |
Funder type | ||
Industry | 17/30 | 56.7 |
Non-industry | 13/30 | 43.3 |