The dutch functional performance inventory: Validity and reliability in patients with chronic obstructive lung disease

Background: Performing activities of daily living (ADLs) is an important outcome measure in chronic obstructive pulmonary disease (COPD). The functional performance inventory (FPI) can be used to measure ADL performance in people with COPD. Objective: The aims are to report translation of the FPI into the Dutch language and evaluate the validity and reliability of the translated version in a Dutch COPD population.

Methods: The FPI was translated, after which validation and test-retest reliability studies were conducted. The Consensus-Based Standards for Selection of Health Status Measurement Instruments checklist was used. The Clinical COPD Questionnaire (CCQ), the self-administered Chronic Respiratory Questionnaire-Standardized, and the Medical Research Council Dyspnea Scale were used in the validation study. Test-retest reliability was estimated across 2 weeks in patients with stable COPD.

Results: Participants were patients with COPD from the Netherlands who took part in either the validation (n = 90) or reliability study (n = 60). The validity analyses showed that, as hypothesized, the household maintenance and physical exercise subscales of the Dutch version of the FPI had high correlations with the CCQ functional status domain; the total FPI had a correlation of .44, with CCQ functional status domain. Across the subscales, score reliability estimated with Cronbach's alpha ranged from .55 (Body Care) to .97 (Household Maintenance); total score alpha was .98. Intraclass correlations (ICCs) ranged from .84 (Social Activities) to .97 (Body Care and Household Maintenance); total scale ICC was .98. Recreation and Spiritual Activity subscales varied significantly on retesting at 2 weeks.

Discussion: Scores on the Dutch FPI were reliable and reproducible. Evidence for validity was reasonable, but less strong than that reported in studies from other populations.