The Australian/Canadian osteoarthritis hand index in a community-dwelling population of older adults: reliability and validity.

OBJECTIVE: To assess the acceptability and measurement properties of the Australian/Canadian Osteoarthritis Hand Index (AUSCAN) applied to a community-dwelling population of older adults with hand problems.
METHODS: Data were obtained from 2 related sources: 2,113 responders to a 2-stage cross-sectional postal survey who reported hand problems in the previous 12-months, and 55 participants with hand problems completing a clinical assessment. The AUSCAN subscales were assessed for data quality and scaling properties. Test-retest reliability was assessed in clinical participants reporting no change in their hand condition at 1 month. Construct and criterion validity were evaluated using other data from the survey and clinical assessment. Internal consistency of the subscales was tested using Cronbach's alpha and item-total correlations.
RESULTS: AUSCAN subscales had high completion rates in the survey (missing data: 2.3-2.7%). Subscale scores covered the possible range but were skewed towards lower pain, stiffness, and functional problems. Test-retest reliability estimates supported the use of the pain and stiffness subscales (rho > 0.7), with the estimate for stiffness being slightly lower (rho = 0.64). The subscales demonstrated both construct validity (significantly higher subscale scores in participants reporting a recent general practitioner consultation for their hand problems and high correlations with hand function performance measures) and criterion validity (high correlations with generic health measures and disease-specific measures).
CONCLUSION: The AUSCAN is a valid and reliable measure of hand problems in a community-dwelling population of older adults. The AUSCAN performs well both in terms of its internal reliability and its relationship with external constructs.