LAUSR

BACKGROUND Participation in life roles is a critical patient-centred health outcome associated with morbidity and mortality in older adults but it is not routinely measured in people with chronic obstructive pulmonary disease (COPD). We aimed to validate a participation measure, the Late Life Disability Instrument (LLDI), in people with COPD. RESEARCH QUESTION To what extent does the LLDI demonstrate test-retest measurement error and reliability, internal consistency, construct and face validity, and floor/ceiling effects when applied to people with COPD? STUDY DESIGN and Methods: Cross-sectional study. LLDI scores were compared to scores on measures of theoretically-related constructs and between groups based on symptom severity, prognosis and frailty. A subsample (n=36) completed the LLDI a second time over the phone within one week. Participants and healthcare professionals (HCPs) were asked about the relevance, comprehensiveness and comprehensibility of the LLDI. Floor/ceiling effects were explored and the internal consistency (Cronbach's alpha) of the LLDI was calculated. RESULTS Ninety-six older adults with COPD participated. The frequency (LLDI-F) and limitation (LLDI-L) domains of the LLDI had excellent test-retest reliability (ICC2,1 0.90, SEM 1.74 points and ICC2,1 0.90, SEM 3.16 points, respectively). Both domains had fair correlations with physical function, depression, and quality of life (r = 0.38 to 0.59). The relationship with anxiety was poor for LLDI-F (r = -0.21) and fair for LLDI-L (r = -0.45). Both domains discriminated between people with different symptom severity, prognosis and frailty (p ≤ 0.026). Neither domain showed floor/ceiling effects and Cronbach's alpha was 0.69 and 0.91 for LLDI-F and LLDI-L, respectively. All HCPs and most participants agreed that the LLDI measures participation (79%) and that the items were relevant (81%). INTERPRETATION The LLDI shows test-retest reliability, internal consistency and construct and face validity in people with COPD. The LLDI can be used to assess participation in this population.