Table 5.
Descriptors in the study design/masking field in the analysed registered trial protocols on ClinicalTrials.gov (N=157)
| Blinding terminology used in analysed registered clinical trial protocols | N |
| Quadruple (participant, care provider, investigator, outcomes assessor) | 39 |
| None (open label) | 22 |
| Single (participant) | 15 |
| Double (participant, investigator) | 14 |
| Double (participant, outcomes assessor) | 14 |
| Triple (participant, investigator, outcomes assessor) | 13 |
| Triple (participant, care provider, investigator) | 12 |
| Single (outcomes assessor) | 8 |
| Single (investigator) | 6 |
| Double (participant, care provider) | 5 |
| Triple (participant, care provider, outcomes assessor) | 4 |
| Study described as observational, without information about blinding/masking | 2 |
| Double (investigator, outcomes assessor) | 1 |
| Masking: triple (participant, care provider, investigator) | 1 |
| Single (care provider) | 1 |