Validation of a Limitations in Daily Activities Scale for Chronic Pain.

Limitations in physical function and participation are important domains of assessment in chronic pain. In 1995, the International Association for the Study of Pain distributed a self-report measure of functional limitations. Although the questionnaire has been used in research studies, it has never been subjected to a thorough investigation of its measurement properties. In this study, 941 patients with chronic pain completed the 16-item Limitations in Daily Activities Scale (LIDAS) at 2 pretreatment and 1 post-treatment assessment points. Individual item analysis favored a 13-item scale. This 13-item LIDAS had a confirmed 3-factor structure consisting of limitations in personal care, global participation, and specific tasks. Reliability analyses for the total scale (α = .90), as well as for each factor individually (αs = .82-.84), indicated good internal consistency, test-retest reliability (intraclass correlations = .65-.88 over varying time intervals), and responsiveness to change with treatment. LIDAS scores correlated as expected with measures of pain intensity, pain cognitions, and depression, as well as with other self-report and clinician-administered measures of functional performance. Using patient global ratings as anchors, a minimal clinically important difference of 5 points was established as a criterion for meaningful individual improvement after treatment. In conclusion, the LIDAS is a reliable, valid, and clinically relevant option for assessing limitations in physical function and participation in patients with chronic pain.

PERSPECTIVE: Physical function and participation comprise a core dimension in the assessment of chronic pain. This study demonstrates that the LIDAS is a reliable and valid measure of this dimension, with good applicability for documenting clinically important change with treatment.