Bruynesteyn K, Wanders A, Landewé R, van der Heijde D. How the type of risk reduction influences required sample sizes in randomised clinical trials.
Ann Rheum Dis 2004;
63:1368-71. [PMID:
15231507 PMCID:
PMC1754827 DOI:
10.1136/ard.2003.014035]
[Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
To increase change between groups, randomised clinical trials (RCT) often include patients with high risk for a particular outcome, by inclusion criteria that select predictors for that outcome. This increases the statistical power, and fewer patients are required for that RCT. The way in which patient selection influences the power, and thus sample size required, depends on how an intervention reduces the individual risk: by an absolute or relative risk reduction model.
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