On the proper use of the crossover design in clinical trials: part 18 of a series on evaluation of scientific publications.

Deutsches Ärzteblatt International
Stefan Wellek, Maria Blettner

Abstract

Many clinical trials have a crossover design. Certain considerations that are relevant to the crossover design, but play no role in standard parallel-group trials, must receive adequate attention in trial planning and data analysis for the results to be of scientific value. The authors present the basic statistical methods required for the analysis of crossover trials, referring to standard statistical texts. In the simplest and most common scenario, a crossover trial involves two treatments which are consecutively administered in each patient recruited in the study. The main purpose served by the design is to provide a basis for separating treatment effects from period effects. This is achieved via computing the treatment effects separately in two sequence groups formed via randomization. The differences between treatment effects can be assessed by means of a standard t-test for independent samples using the intra-individual differences between the outcomes in both periods as the raw data. The existence of carryover effects must be ruled out for this method to be valid. This assumption is usually checked using a pre-test, which is also described in this article. Finally, we briefly discuss the use of nonparametric tests instea...Continue Reading

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Citations

Jun 29, 2017·Journal of Sports Sciences·Florian BeaudouinAnne Hecksteden
Nov 23, 2017·Comprehensive Child and Adolescent Nursing·Ludwy HandhayantiTri Budiati
Aug 11, 2017·Journal of Athletic Training·Gino PanzaJeffrey E Edwards
Nov 18, 2017·Statistical Methods in Medical Research·P J Godolphin, E J Godolphin
Aug 20, 2019·The Journals of Gerontology. Series A, Biological Sciences and Medical Sciences·Shao Feng MokDavid J Handelsman
Jul 25, 2019·Brazilian Dental Journal·Heloisa Sousa GomesLuciane Rezende Costa
Jan 17, 2020·International Journal of Sport Nutrition and Exercise Metabolism·James A BettsGreg Atkinson
Sep 18, 2017·Archives of Disease in Childhood. Fetal and Neonatal Edition·Daniel KlotzHans Fuchs
Jun 23, 2015·Annals of Neurology·Lynn Marie TrottiDavid B Rye
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Jul 11, 2019·EuroIntervention : Journal of EuroPCR in Collaboration with the Working Group on Interventional Cardiology of the European Society of Cardiology·Ahmed ElghamazKeith Oldroyd
Jun 15, 2016·CPT: Pharmacometrics & Systems Pharmacology·G SmaniaM Cella
Nov 20, 2019·Biometrics·Crystal T NguyenMichael R Kosorok
Aug 2, 2019·BMJ : British Medical Journal·Kerry DwanDiana Elbourne
Sep 22, 2018·Clinical Journal of the American Society of Nephrology : CJASN·Jessica KendrickMichel Chonchol
Nov 30, 2019·Applied Physiology, Nutrition, and Metabolism = Physiologie Appliquée, Nutrition Et Métabolisme·Nicholas PreobrazenskiBrendon J Gurd
Jan 31, 2020·Journal of the American Society of Nephrology : JASN·Dominique M BovéeEwout J Hoorn
Aug 26, 2020·Cognitive, Affective & Behavioral Neuroscience·John P PowersKevin S LaBar
Apr 22, 2016·Journal of Diabetes·Tao WangWilliam J Huster
Aug 23, 2019·Deutsches Ärzteblatt International·Stefan WellekMaria Blettner

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