Does the low prevalence affect the sample size of interventional clinical trials of rare diseases? An analysis of data from the Aggregate Analysis of ClinicalTrials.gov Hee, Siew Wana email:
[email protected] Willis, Adrianb email:
[email protected] Tudur Smith, Catrinc email:
[email protected] Day, Simond email:
[email protected] Miller, Franke email:
[email protected] Madan, Jasonb email:
[email protected] Posch, Martinf email:
[email protected] Zohar, Sarahg email:
[email protected] and Stallard, Nigela email:
[email protected] aStatistics and Epidemiology Unit, Division of Health Sciences, Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK bWarwick Clinical Trials Unit, Division of Health Sciences, Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK; cNorth West Hub for Trials Methodology Research, Department of Biostatistics, Liverpool L69 3GL, UK dClinical Trials Consulting and Training Limited, Buckingham, UK eDepartment of Statistics, Stockholm University, Sweden fSection of Medical Statistics, CeMSIIS, Medical University of Vienna, Austria gINSERM, U1138, team 22, Centre de Recherche des Cordeliers, Université Paris 5, Université Paris 6, Paris, France Corresponding author Dr Siew Wan Hee, Statistics and Epidemiology Unit, Division of Health Sciences, Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK. Email:
[email protected]. 1 Abstract Background Clinical trials are typically designed using the classical frequentist framework to constrain type I and II error rates. Sample sizes required in such designs typically range from hundreds to thousands of patients which can be challenging for rare diseases.