Darcy Ummels

24 | Chapter 2 Remoortel et al. 18 recently published a literature review regarding validity and reliability of activity trackers in people with a chronic disease. It was confirmed that most commercially available activity trackers have been studied in healthy populations 17,19 ‐ 21 , and little is known about which types of activity trackers provide valid results in people with chronic diseases. In their review, they found that only 12 of the 134 studies on validity of activity trackers included people with a chronic disease. 18 Of the 12 identified studies, only 3 evaluated activities of daily living (free living or an activity protocol) in people with a chronic disease 22 ‐ 24 ; however, these studies only tested noncommercially available activity trackers and mainly evaluated energy expenditure instead of step count. Results from other studies with participants with chronic diseases are not generalizable to daily practice because they did not have step count as the primary outcome (e.g., mostly energy expenditure) 25 ‐ 31 , involved only walking and no other activities of daily living 32 ‐ 35 , or free living conditions were not protocoled (e.g., cardiac patients 36 and patients with COPD 37 or cancer 38 ). As stated before, for both people with a chronic disease and their therapists, insight into physical activity level and patterns outside of therapy are very relevant. Since no article was found that matched our criteria, we decided to validate 9 potential trackers ourselves in people with a chronic disease. The main aim of this study was to investigate the validity of 9 selected commercially available activity trackers for measuring step count in people with a chronic disease receiving physiotherapy during a selected set of activities of daily living. Results from this study should provide guidance in choosing the right activity tracker for people with a chronic disease. Methods Study design A cross ‐ sectional validity study with 9 activity trackers was performed in patients with chronic diseases. The data collection took place over a 1 ‐ year period. All participants provided written informed consent. This study was approved by the local ethics boards (Atrium ‐ Orbis ‐ Zuyd Medical Ethical Committee, 15 ‐ N ‐ 48; Adelante Medical Ethical Committee, MEC ‐ 15 ‐ 07). Participants Participants were recruited from 2 physiotherapy practices (Fysiotherapie Schaesberg and ParaMedisch Centrum Zuid) and a rehabilitation center (Adelante Zorggroep) in the