Evaluation of the Content Validity Index of the Australian/Canadian Osteoarthritis Hand Index, the Patient-Rated Wrist/Hand Evaluation and the Thumb Disability Exam in People with Hand Arthritis

Abstract

BackgroundThe Australian/Canadian Osteoarthritis Hand Index (AUSCAN), the Patient-Rated Wrist/Hand Evaluation (PRWHE) and the Thumb Disability Exam (TDX) are patient-reported outcome measures (PROM) used to assess pain and hand function in patients with hand arthritis. This study evaluated the content validity of PRWHE, AUSCAN and TDX. MethodsThis study enrolled participants with hand arthritis to rate the items of all 3 PROM in terms of relevance and clarity. The Content Validity Index (CVI) was computed for each item in each scale (I-CVI) as well as for the overall scale (S-CVI). Kappa was used to determine the inter-rater agreement among the raters. ResultsOverall, 64 individuals with hand arthritis (27% with OA, 67% with rheumatoid arthritis and 6% with psoriatic arthritis) participated in the study. The I-CVI for all items and all scales was very high (I-CVI > 0.76) and the modified Kappa agreement among the raters demonstrated excellent agreement (k>0.76).The S-CVI for all PROMs was found very high for relevance (PRWHE = 0.85, 95% CI 0.82 to 0.88; TDX = 0.87, 95% CI 0.85 to 0.89 and AUSCAN = 0.92, 95% CI 0.90 to 0.94) and for clarity (PRWHE = 0.95, 95% CI 0.93 to 0.97; TDX = 0.91, 95% CI 0.89 to 0.94 and AUSCAN = 0.99, 95% CI 0.98 to 1.00) respectively. ConclusionsThis study demonstrated very high content validity indices for the PRWHE, AUSCAN, and TDX; with strong consensus across raters. This augments prior statistical evidence supporting statistical measurement properties, to provide support for the content validity.