Table 2 Comparison of HPV vaccine clinical study reports with trial register entries and journal publications: inclusion of protocol and reporting of trial design aspects including PICO criteria
Inclusion of protocol and reporting of trial design aspects including PICO criteria | Clinical study reports: N = 24 | Trial register entries: N = 24 | Publications: N = 23 |
|---|---|---|---|
Protocol | |||
Included in study document | 10 (42%) | 0 (0%) | 2 (9%) |
- Prespecified outcomes | 10 (100%) | Not applicable | 2 (100%) |
- Included statistical analysis plan | 10 (100%) | Not applicable | 2 (100%) |
Reporting of six major design-related biases defined by the Cochrane Handbooka | |||
Randomization method was explicitly specified | 24 (100%) | 0 (0%) | 22 (96%) |
Allocation concealment was explicitly specified | 24 (100%) | 0 (0%) | 17 (74%) |
Blinding of outcome assessors was explicitly specified | 24 (100%) | 23 (96%) | 17 (74%) |
Blinding of personnel was explicitly specified | 24 (100%) | 11 (46%) | 12 (52%) |
Blinding of participants was explicitly specified | 24 (100%) | 23 (96%) | 12 (52%) |
Loss to follow-up (attrition) was explicitly accounted for | 24 (100%) | 20 (83%) | 23 (100%) |
Population | |||
Specified inclusion criteria | 24 (100%) | 24 (100%) | 22 (96%) |
- Mean number of inclusion criteria | 7.0 | 5.8 | 4.0 |
Specified exclusion criteria | 24 (100%) | 24 (100%) | 20 (87%) |
- Mean number of exclusion criteria | 17.8 | 11.7 | 5.0 |
Intervention | |||
Specified HPV vaccine antigens | 24 (100%) | 18 (75%) | 23 (100%) |
Specified HPV vaccine adjuvants | 24 (100%) | 8 (33%) | 23 (100%) |
Specified dose | 24 (100%) | 6 (25%) | 21 (91%) |
Comparator | |||
Specified content | 24 (100%) | 8 (33%) | 23 (100%) |
Specified dose | 24 (100%) | 6 (25%) | 21 (91%) |
Reported active comparator as a ‘placebo’b | 14 (58%) | 13 (54%) | 17 (74%) |
Outcomes | |||
Primary outcomes explicitly specified | 24 (100%) | 24 (100%) | 18 (78%) |
- Mean number of primary outcomes | 1.6 | 3.5 | 1.2 |
Secondary outcomes explicitly specified | 24 (100%) | 24 (100%) | 14 (61%) |
- Mean number of secondary outcomes | 8.8 | 13.0 | 3.2 |