Extension Reports in Clinical Trials: A Systematic Review and Consequent Guidance
Authors' conclusion
This first systematic investigation into the reporting of extension studies found a great diversity in practice, noting several issues that need more adequate consideration.
Study context
- Population
- Extension reports of CV trials published Jan 2019–Oct 2023 in 7 high-impact medical journals
- Participants
- 69 participants64 trials
- Outcome
- Characteristics of extension reports of CV trials
Methodological details2 reviewers, standard proforma
- 2 reviewers
- Standard proforma
Pooled result
As reported in the abstract
- Extension reports identified (of 1,388 papers screened), across 64 trials
- 69
- CHD topic (most common)
- 20
- Original 1-year report with extension at 2, 3, 5 or 10 years (most common)
- 20
- Superiority hypothesis
- 68
- Same primary outcome as original publication
- 53
- Nonrandomized open-label extensions (no concurrent control arm)
- 7
- Treatment crossovers permitted during extension
- 18
- Alternatives to ITT analysis used
- 16
- Prespecified extension studies
- 38
- Dedicated protocols or statistical analysis plans
- 10
- Landmark analyses (not based on original randomized groups)
- 39
- Loss to follow-up >10% (of 50 reports with clear reporting)
- 10
Original publication
Extension Reports in Clinical Trials: A Systematic Review and Consequent Guidance. J Am Coll Cardiol. Published 11 February 2026. doi:10.
Composed by AI from the published abstract and checked against it. How Briefs are made →