A study of measurement properties of the Life-Space Assessment questionnaire in older adults with chronic obstructive pulmonary disease

Objective: To test the measurement properties (reliability, interpretability, and validity) of the Life-Space Assessment questionnaire for older adults with chronic obstructive pulmonary disease. Design: Clinimetric study. Setting: Pneumology service, ambulatory care, Sao Paulo, SP, Brazil. Participants: Consecutive sample of older adults (n=62; 38 (61%) men, 24 (39%) women) with chronic obstructive pulmonary disease. Interventions: Not applicable. Main outcome measures: Life-Space Assessment questionnaire assesses five space levels visited by the older adult in four weeks prior to the assessment. We tested the following measurement properties of this questionnaire: reliability (reproducibility assessed by a type-2,1 intraclass correlation coefficient (ICC2,1); internal consistency assessed by the Cronbach's alpha; measurement error by determining the standard error of measurement (SEM)), interpretability (minimum detectable change with 90% confidence (MDC90); ceiling and floor effects by calculating the proportion of participants who achieved the minimum and maximum scores), and validity by Pearson's correlation test between the Life-Space Assessment questionnaire scores and number of daily steps assessed by accelerometry. Results: Reproducibility (ICC2,1) was 0.90 (95% confidence interval (CI): 0.84-0.94), and internal consistency (Cronbach's alpha) was 0.80 (range=0.76-0.80 for each item deleted). SEM was 3.65 points (3%), the MDC90 was 0.20 points, and we observed no ceiling (2%) or floor (6%) effects. We observed an association between the score of the Life-Space Assessment questionnaire and daily steps (r=0.43; P=0.01). Conclusion: Life-Space Assessment questionnaire shows adequate measurement properties for the assessment of life-space mobility in older adults with chronic obstructive pulmonary disease.