TY - JOUR T1 - The PROactive instruments to measure physical activity in patients with chronic obstructive pulmonary disease JF - European Respiratory Journal JO - Eur Respir J DO - 10.1183/09031936.00183014 SP - ERJ-01830-2014 AU - Elena Gimeno-Santos AU - Yogini Raste AU - Heleen Demeyer AU - Zafeiris Louvaris AU - Corina de Jong AU - Roberto A. Rabinovich AU - Nicholas S. Hopkinson AU - Michael I. Polkey AU - Ioannis Vogiatzis AU - Maggie Tabberer AU - Fabienne Dobbels AU - Nathalie Ivanoff AU - Willem I. de Boer AU - Thys van der Molen AU - Karoly Kulich AU - Ignasi Serra AU - Xavier Basagaña AU - Thierry Troosters AU - Milo A. Puhan AU - Niklas Karlsson AU - Judith Garcia-Aymerich Y1 - 2015/05/28 UR - http://erj.ersjournals.com/content/early/2015/05/28/09031936.00183014.abstract N2 - No current patient-centred instrument captures all dimensions of physical activity in chronic obstructive pulmonary disease (COPD). Our objective was item reduction and initial validation of two instruments to measure physical activity in COPD.Physical activity was assessed in a 6-week, randomised, two-way cross-over, multicentre study using PROactive draft questionnaires (daily and clinical visit versions) and two activity monitors. Item reduction followed an iterative process including classical and Rasch model analyses, and input from patients and clinical experts.236 COPD patients from five European centres were included. Results indicated the concept of physical activity in COPD had two domains, labelled “amount” and “difficulty”. After item reduction, the daily PROactive instrument comprised nine items and the clinical visit contained 14. Both demonstrated good model fit (person separation index >0.7). Confirmatory factor analysis supported the bidimensional structure. Both instruments had good internal consistency (Cronbach's α>0.8), test–retest reliability (intraclass correlation coefficient ≥0.9) and exhibited moderate-to-high correlations (r>0.6) with related constructs and very low correlations (r<0.3) with unrelated constructs, providing evidence for construct validity.Daily and clinical visit “PROactive physical activity in COPD” instruments are hybrid tools combining a short patient-reported outcome questionnaire and two activity monitor variables which provide simple, valid and reliable measures of physical activity in COPD patients.Both PROactive hybrid tools are simple, valid, and reliable measures of physical activity in COPD patients http://ow.ly/LJqP8 ER -