Structural validity and construct validity of the Dutch-Flemish PROMIS® physical function-upper extremity version 2.0 item bank in Dutch patients with upper extremity injuries

Introduction: Aim of this study was to validate the Dutch–Flemish Patient-Reported Outcomes Measurement Information System Physical Function–Upper Extremity version 2.0 item bank in patients with upper extremity injuries. Materials and methods: Cross-sectional study. Structural validity was assessed using Confirmatory Factor Analysis examining unidimensionality. In addition, a bi-factor model was fitted. Internal consistency was assessed by Cronbach’s alpha. Construct validity was examined by assessing correlations with legacy instruments Disability of Arm Shoulder and Hand, Patient Reported Wrist Evaluation and Michigan Hand Questionnaire subscale Activities in Daily Life. Results: A total of 303 patients (144 female) with mean age of 50 years (standard deviation 18) were included. Confirmatory Factor Analysis showed Comparative Fit Index of 0.94, a Tucker Lewis Index of 0.93, a Root Mean Square Error of Approximation of 0.12 and a Standardized Root Mean Residual of 0.09. Factor loadings were all above 0.70. Bifactor analysis showed an omega-H of 0.79 and Explained Common Variance of 0.67. The correlations with the legacy instruments were as expected or higher than expected. Conclusion: The Dutch-Flemish Patient-Reported Outcomes Measurement Information System Physical Function–Upper Extremity version 2.0 item bank measures a unidimensional trait and sufficient construct validity was found.IMPLICATIONS FOR REHABILITATION Completing Patient Reported Outcomes is time-consuming for patients and interpretability of outcomes is sometimes unclear due to some variation in psychometric properties. Computerized Adaptive Testing reduces the burden for patients by using an algorithm which decreases the amount of questions that need to be answered to 4 to 7 items. The Dutch-Flemish Patient-Reported Outcomes Measurement Information System Physical Function–Upper Extremity version 2.0 item bank measures a unidimensional trait and has sufficient structural validity, internal consistency and construct validity. After calibration of the Patient-Reported Outcomes Measurement Information System Physical Function–Upper Extremity version 2.0, the item bank is operable to use with Computerized Adaptive Testing.