The AUSCAN and PRWHE Demonstrate Comparable Internal Consistency and Validity in Patients With Early Thumb Carpometacarpal Osteoarthritis

Abstract

Background: The Australian/Canadian Osteoarthritis Hand Index (AUSCAN) and Patient-Rated Wrist-Hand Evaluation (PRWHE) are 2 patient-related outcome measures to assess pain and disability in patients with osteoarthritis (OA). The purpose of this study was to evaluate the AUSCAN and PRWHE in a large-scale, longitudinal cohort of patients with early thumb carpometacarpal (CMC) OA. Methods: We obtained baseline data on 135 individuals (92 with early CMC OA participants and 43 asymptomatic controls) and at follow-up (year 1.5) on 83 individuals. We assessed the internal consistency using Cronbach alpha, and construct and criterion validity using other pain scales and objective measures of strength, respectively. We also examined the correlation between the AUSCAN and PRWHE and correlation coefficients at baseline and follow-up, as well as the correlation between changes in these instruments over the follow-up period. Results: Internal consistency was high for both AUSCAN and PRWHE totals and subscales (Cronbach α > 0.70). Both instruments demonstrated construct validity compared with the Verbal Rating Scale ( r = 0.52-0.60, P < .01), an assessment of pain, and moderate criterion validity compared with key pinch and grip strength ( r = −.24 to −.33, P < .05). These instruments were highly correlated with each other at baseline and follow-up time points ( r = 0.76−.94, P < .01), and changes in a patient’s total scores over time were also correlated ( r = 0.83, P < .01). Conclusions: The AUSCAN and PRWHE are both valid assessments for pain and/or disability in patients with early thumb CMC OA.