Background and objective: Exercise limitation is a common finding in chronic obstructive pulmonary disease (COPD) patients and has an important role in disease prognosis and the use of health care services. There are no questionnaires in Spanish language that evaluate the impact of the disease in the activities of daily living in these patients. Our objective was to adapt and validate the Spanish versions of 2 standard questionnaires for assessment of physical activity: the London Chest Activity of Daily Living scale (LCADL) and the Modified Baecke Physical Activity Questionnaire (modified Baecke).
Patients and method: After carrying out the translation and back-translation, the 2 questionnaires were administered to 55 patients with COPD (mean age [standard deviation]: 66  years; forced expiratory volume in 1 s: 1.2 [0.5] l, 38 %) in 2 occasions and a conventional exercise test was performed.
Results: Cronbach's alpha coefficient was very high (0.98 and 0.97 for LCADL and modified Baecke, respectively; p < 0.0001 each). Intraclass correlation coefficients of the test re-test reliability was also very high (0.97 and 0.96, respectively). Mean values of the questionnaires in the 2 administrations were 20 (11) vs 19 (11) for LCADL (p = 0.26), and 15 (9) vs 14 (9) for modified Baecke (p = 0.51). The 2 questionnaires showed a significant correlation with quality of life (St. George's Respiratory Questionnaire), dyspnea score (Medical Research Council scale) and 6 min walk test.
Conclusions: The Spanish versions of these 2 questionnaires to assess physical activity are relibale and they display the expected association with health related quality of life, dyspnea score, and the 6 min walk test, confirming their validity. Therefore, we propose its use to complement the assessment of physical activity in those patients with COPD in whom direct measurements of this variable are not available.