BACKGROUND: Dyspnea and fatigue frequently impair the ability to perform activities of daily living (ADL) in patients with chronic obstructive pulmonary disease. Questionnaires and scales have been used to assess limitations in ADL. The London Chest Activity of Daily Living (LCADL) scale is responsive to intervention to a higher extent when compared with other tools. However, the minimal detectable change (MDC) for this scale remains unknown. The aim of this study was to determine the MDC for functional status improvement measured by the LCADL scale in patients with chronic obstructive pulmonary disease.
METHODS: Forty patients (20 men, 66 ± 7 years, forced expired volume in 1 second 44 ± 16% predicted) participated in a 3-month high-intensity exercise training program. Before and after the protocol, participants complete the LCADL scale and the Saint George Respiratory Questionnaire. To calculate the MDC, we used the standard error of measurement and the effect size (distribution-based estimates).
RESULTS: There was improvement in the LCADL self-care, domestic and leisure domains, and total score after the training program, with a strong trend for improvement in the physical activity domain. The MDC estimated for the LCADL were 0.89, 2.60, 0.44, 0.58, and 3.88 points for self-care, domestic, physical, and leisure domains, and total score, respectively. Correlations between changes in LCADL and in the Saint George Respiratory Questionnaire were weak (r < 0.4 for all).
CONCLUSION: This study provided the MDC for the domains and total score of the LCADL. A change of 4 points in the total score of the LCADL can be interpreted as a meaningful change.