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>Journals >Gaceta Médica de México >Year 2018, Issue 3

Loria A
Sample size in clinical protocols
Gac Med Mex 2018; 154 (3)

Language: Español
References: 3
Page: 409-412
PDF: 190.95 Kb.

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Sample size calculation in clinical protocols submitted to the review board of the Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán frequently has three types of problems: insufficient data for sample size recalculation, use of obsolete equations that do not take the beta error into account, and use of equations that do not correspond to the study design. In this document, we discuss the four data that should be included in the clinical protocols of randomized controlled trials that compare drugs versus placebo in superiority trials, and versus active controls in non-inferiority studies.

Key words: Sample size, Ethics, Clinical research, Non-inferiority trials.


  1. Dickersin K, Chalmers I. Recognizing, investigating and dealing with incomplete and biased reporting of clinical research: from Francis Bacon to the WHO. J R Soc Med. 2011;104:532-538.

  2. Clark T, Berger U, Mansmann U. Sample size determinations in original research protocols for randomised clinical trials submitted to UK research ethics committees: review. Brit Med J. 2013;346:f1135.

  3. Flight L, Julious SA. Practical guide to sample size calculations: non-inferiority and equivalence trials. Pharmaceutical Stat. 2016;15:80-88. - Figura 1. IC 95 % de cinco estudios (A-E). Diferencia de tratamiento nuevo menos control activo.

>Journals >Gaceta Médica de México >Year 2018, Issue 3

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