Reliability, validity, and responsiveness of the Japanese version of the patient-rated elbow evaluation

BACKGROUND The patient-rated elbow evaluation (PREE) is a joint-specific, self-administered questionnaire consisting of a pain scale (PREE-P) and a functional scale (PREE-F), the latter consisting of specific function (PREE-SF) and usual function (PREE-UF). The purpose of this study was to cross-culturally adapt the PREE into Japanese (PREE-J) and to test its reliability, validity, and responsiveness. METHODS A consecutive series of 74 patients with elbow disorder completed the PREE-J, the Japanese version of the disabilities of the arm, shoulder, and hand (DASH-JSSH) questionnaire, and the official Japanese version of the 36-Item Short-Form Health Survey (SF-36). Of the 74 patients, 53 were reassessed for test-retest reliability 1 or 2 weeks later. Reliability was investigated in terms of reproducibility and internal consistency. The validity of the PREE-J was examined by factor analysis, and correlation coefficients were obtained using the PREE-J, DASH-JSSH, and SF-36. Responsiveness was examined by calculating the standardized response mean (SRM) and effect size after elbow surgery in 53 patients. RESULTS Cronbach's α coefficients for PREE-P, PREE-F, and PREE were 0.92, 0.97, and 0.97, respectively, and the corresponding intraclass correlation coefficients were 0.92, 0.93, and 0.94, respectively. Unidimensionality of PREE-P and PREE-F was confirmed by factor analysis. The coefficients of correlation between PREE-P and PREE-F or DASH-JSSH were 0.81 and 0.74, respectively; that between PREE-F and DASH-JSSH was 0.86, and those between DASH-JSSH and PREE-SF or PREE-UF were 0.85 and 0.82, respectively. Moderate correlation was observed in "physical functioning" for SF-36 and PREE-F (r = -0.69) or PREE (r = -0.68). The SRMs/effect sizes of PREE-P (1.31/1.32) or PREE (1.28/1.12) were more responsive than the DASH-JSSH (0.99/0.85), "bodily pain" (-1.15/-1.43), and "physical functioning" (-0.70/-0.44) in SF-36. CONCLUSION The PREE-J represents a reliable, valid, and responsive instrument and has evaluation capacities equivalent to those of the original PREE.