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QUALITY OF SAMPLE SIZE ESTIMATION IN TRIALS OF MEDICAL DEVICES: HIGH-RISK DEVICES FOR NEUROLOGICAL CONDITIONS AS EXAMPLE

Published online by Cambridge University Press:  15 May 2017

Britta Olberg ,
Matthias Perleth ,
Katja Felgentraeger ,
Sandra Schulz  and
Reinhard Busse
Britta Olberg
Affiliation:
Medical Consultancy Department, German Federal Joint Committee, Department of Health Care Management, Berlin University of Technologyb.olberg@campus.tu-berlin.de
Matthias Perleth
Affiliation:
Medical Consultancy Department, German Federal Joint Committee
Katja Felgentraeger
Affiliation:
Medical Consultancy Department, German Federal Joint Committee
Sandra Schulz
Affiliation:
Medical Consultancy Department, German Federal Joint Committee
Reinhard Busse
Affiliation:
Department of Health Care Management, Berlin University of Technology
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Abstract

Background: The aim of this study was to assess the quality of reporting sample size calculation and underlying design assumptions in pivotal trials of high-risk medical devices (MDs) for neurological conditions.

Methods: Systematic review of research protocols for publicly registered randomized controlled trials (RCTs). In the absence of a published protocol, principal investigators were contacted for additional data. To be included, trials had to investigate a high-risk MD, registered between 2005 and 2015, with indications stroke, headache disorders, and epilepsy as case samples within central nervous system diseases. Extraction of key methodological parameters for sample size calculation was performed independently and peer-reviewed.

Results: In a final sample of seventy-one eligible trials, we collected data from thirty-one trials. Eighteen protocols were obtained from the public domain or principal investigators. Data availability decreased during the extraction process, with almost all data available for stroke-related trials. Of the thirty-one trials with sample size information available, twenty-six reported a predefined calculation and underlying assumptions. Justification was given in twenty and evidence for parameter estimation in sixteen trials. Estimates were most often based on previous research, including RCTs and observational data. Observational data were predominantly represented by retrospective designs. Other references for parameter estimation indicated a lower level of evidence.

Conclusions: Our systematic review of trials on high-risk MDs confirms previous research, which has documented deficiencies regarding data availability and a lack of reporting on sample size calculation. More effort is needed to ensure both relevant sources, that is, original research protocols, to be publicly available and reporting requirements to be standardized.

Keywords

Medical devicesRandomized controlled trialsSample size calculationNeurological
Type
Assessments
Information
International Journal of Technology Assessment in Health Care , Volume 33 , Issue 1 , 2017 , pp. 103 - 110
Copyright
Copyright © Cambridge University Press 2017 

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