Measuring free-living activity in clinical trials


In many clinical trials, improvements in physical activity and mobility are important secondary outcomes.  These are often estimated using in-clinic controlled assessments of exercise capacity such as treadmill tests and corridor circuits including the six minute walking test.  Many drug treatments that improve symptoms, may also enable increased activity and mobility with corresponding improvements in quality of life.  These improvements may be better examined by measuring free-living activity, and in less active patient populations this may include measuring increased participation in discretionary non-essential tasks requiring levels of physical activity.

While activity monitors have been used in clinical trials, some researchers consider a number of perceived barriers limiting their use.  These include: (i) regulatory acceptance of the validity of devices and the data management assumptions made; (ii) scientific understanding of the data recorded and how to derive meaningful summary outcome measures; and (iii) a lack of standards for implementing activity data collection in clinical trial protocols.  

With reference to the study of less active patient populations, this open access article published in Contemporary Clinical Trials addresses these issues and importantly provides recommended standards for implementing activity monitors in study protocols, standards for data management of activity data, and recommended endpoints for study.  While exploring COPD specifically, the recommendations would equally apply to other less active patient populations.

In their review article (Byrom and Rowe, 2016), Dr. Bill Byrom, Senior Director of Product Innovation at ICON, alongside Dr. David Rowe, Reader in Exercise Science in the School of Psychological Sciences and Health at Strathclyde University, develop trial protocol standards for implementing activity monitors including the number of days monitors should be worn, the number of wear-hours per day, and rules to handle missing data to gain reliable estimates of overall activity.  

They focus on a set of pertinent outcome measures important in characterizing activity in less active patients, that may be sensitive to detecting treatment-related changes.  These include measures of sedentary behavior, light to moderate activity and overall activity.  Recommendations are graded with a green-amber-red traffic light system based on the strength of research evidence that support them, and indicate where additional research would be valuable.

The aim of this work is to attempt to take a positive step forward in defining acceptable standards for use of activity monitors in regulatory clinical trials with an aim to eliminating the perceived barriers to wide scale adoption.

The published open access article is available here:
B. Byrom and D.A. Rowe.  (2016) Measuring free-living physical activity in COPD patients: deriving methodology standards for clinical trials through a review of research studies.  Contemporary Clinical Trials; 47:172-184.
Link: http://www.contemporaryclinicaltrials.com/article/S1551-7144(16)30005-2/abstract

ICON’s innovation team contains scientific experts in the area of actigraphy including Marie McCarthy who joined ICON from Phillips Respironics in 2014, Dr. Willie Muehlhausen, Head of Product Innovation, and Dr. Bill Byrom, the co-author of this article.  Our scientific experts can assist with all aspects of study design and activity monitor implementation, including device vendor selection, oversight and management; protocol definition and implementation approach; data management considerations; derived outcome measure definition and selection; and key opinion leader involvement.

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