Development and Validation of a Photonumeric Scale for Evaluation of Volume Deficit of the Hand.

ABSTRACT

BACKGROUND: A validated scale is needed for objective and reproducible comparisons of hand appearance before and after treatment in practice and clinical studies. OBJECTIVE: To describe the development and validation of the 5-point photonumeric Allergan Hand Volume Deficit Scale. METHODS: The scale was developed to include an assessment guide, verbal descriptors, morphed images, and real-subject images for each grade. The clinical significance of a 1-point score difference was evaluated in a review of image pairs representing varying differences in severity. Interrater and intrarater reliability was evaluated in a live-subject validation study (N = 296) completed during 2 sessions occurring 3 weeks apart. RESULTS: A score difference of ≥1 point was shown to reflect a clinically significant difference (mean [95% confidence interval] absolute score difference, 1.12 [0.99-1.26] for clinically different image pairs and 0.45 [0.33-0.57] for not clinically different pairs). Intrarater agreement between the 2 validation sessions was almost perfect (mean weighted kappa = 0.83). Interrater agreement was almost perfect during the second session (0.82, primary end point). CONCLUSION: The Allergan Hand Volume Deficit Scale is a validated and reliable scale for physician rating of hand volume deficit.