- Methodology of randomized-controlled trials in countries* under Gulf Cooperation Councils from 1990 to 2018 (n=406).
| Characteristics | n | % |
|---|---|---|
| Randomization ratio | ||
| None | 369 | 90.9 |
| 1:1 | 30 | 7.4 |
| 1:1:1 | 2 | 0.5 |
| 1:1:1:1 | 1 | 0.2 |
| 2:1 | 1 | 0.2 |
| 2:2:1 | 1 | 0.2 |
| 3:1 | 1 | 0.2 |
| 5:1 | 1 | 0.2 |
| Use of block randomization | ||
| No | 369 | 90.9 |
| Yes | ||
| Single-block size | 16 | 3.9 |
| Multi-block size | 4 | 0.9 |
| Not disclosed block size | 17 | 4.3 |
| Type of design | ||
| Parallel | 357 | 87.7 |
| Cross-over | 31 | 7.6 |
| Cluster-based | 7 | 1.7 |
| Single group assignment | 6 | 1.5 |
| Split-mouth | 4 | 1.0 |
| Split-face | 1 | 0.2 |
| Intention-to-treat (ITT) and per protocol (PP) analyses | ||
| ITT | 292 | 71.8 |
| PP | 96 | 23.7 |
| ITT and PP | 8 | 2.0 |
| NA | 10 | 2.5 |
| Reported overall rate of loss-to-follow up | ||
| Yes | 69 | 17.0 |
| No | 329 | 80.8 |
| NA | 8 | 2.2 |
*Saudi Arabia, Bahrain, United Arab of Emirates, Kuwait, Oman, and Qatar, NA: not applicable, ITT: intention-to-treat analysis, PP: per protocol analysis