Sample Size Calculations in Acute Stroke Trials: A Systematic Review of Their Reporting, Characteristics, and Relationship With Outcome
Abstract
Background and purpose Only a few randomized controlled trials in acute stroke have shown a treatment-related benefit. Inadequate trial design, especially low sample size, may partly explain this failure. We investigated sample size calculations (SSCs) in a systematic review of acute stroke trials. Methods Full reports of nonconfounded randomized controlled trials that recruited patients within 1 week of stroke onset and were published before the end of 2001 were identified from the Cochrane Library and other bibliographic databases. Information on the SSC and outcome event rates was collected for each trial. Results Of 189 identified trial reports, 57 (30%) reported > or =1 components of the SSC, phase II 14/129 (11%) versus phase III 43/60 (72%) (P Conclusions Too few trial publications report the assumptions underlying their SSC. Most trials were underpowered, ie, power <0.90, used inappropriate assumptions for event rates, and were grossly overoptimistic in their expectation of treatment effect. These deficiencies will together have resulted in trials being far too small and reduced their chance of being able to detect real treatment effects.
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Standard methods exist for the calculation of sample size required for a given significance and power.
“Standard methods exist for the calculation of sample size required for a given significance and power.”
From Statistical Analysis of the Primary Outcome in Acute Stroke Trials (2012) · cites this paper as [44]
Standard sample-size methods are well described for both dichotomous and continuous analyses.
“These are well described for both dichotomous and continuous analyses.”
From Statistical Analysis of the Primary Outcome in Acute Stroke Trials (2012) · cites this paper as [44]
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- Authors
- Weaver, C. S., Leonardi-Bee, J., Bath-Hextall, F. J., & Bath, P. M. W.
- Affiliations
- University of Nottingham (GB)
- From Institute of Neurosciences (C.S.W., P.M.W.B.), Institute of Clinical Research (J.L.-B.), and School of Nursing (F.J.B.-H.), University of Nottingham, UK.
- Venue
- Stroke
- Published
- 2004-05
- Volume
- 35
- Issue
- 5
- Pages
- 1216-1224
- ISSN
- 0039-2499 (ISSN-L)
- 1524-4628
- OpenAlex
- W2074204558
- Cited by
- 67
- References
- 0
- Citations by year
- 2026: 2 · 2025: 5 · 2024: 1 · 2023: 3 · 2021: 3 · 2019: 2 · 2018: 2 · 2017: 3 · 2016: 2 · 2015: 5 · 2014: 7 · 2013: 4 · 2012: 3
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- Stroke (publishedVersion)
- PubMed (publishedVersion)
- Funders
- Stroke Association
- Topics
- Physical Sciences › Mathematics › Statistics and Probability › Statistical Methods in Clinical Trials
- Social Sciences › Decision Sciences › Statistics, Probability and Uncertainty › Meta-analysis and systematic reviews
- Physical Sciences › Mathematics › Statistics and Probability › Statistical Methods in Epidemiology
- Keywords
- sample size determination, acute stroke, randomized controlled trials, trial design, statistical power, case fatality, trial reporting quality, treatment effect estimation, stroke prevention
- MeSH terms
- Algorithms, Humans, Mathematics, Publishing, Research Design, Randomized Controlled Trials as Topic, Treatment Outcome, Outcome Assessment, Health Care, Sample Size, Patient Selection, Internet, Stroke
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