The Reha-Toolbox Project: Linking Item Subsets of 3 Established Rehabilitation PROMs to 9 Domains of the Patient-Reported Outcomes Measurement Information System (PROMIS)

Objective: The overarching goal of the patient-reported outcomes measurement information system (PROMIS) is to standardize patient-reported outcomes across settings and health conditions globally. Following this purpose, the Reha-Toolbox study aimed to link item subsets of the World Health Organization Disability Assessment Schedule 2.0 (WHODAS 2.0), the Indicators of Rehabilitation Status (IRES-3), and the Hamburg Modules for the Assessment of Psychosocial Health (HEALTH-49) to the standardized metrics provided by PROMIS.

Design: Cross-sectional, single-group linking study.

Setting: Online survey.

Participants: Experts (N=5) mapped items from the 3 rehabilitation measures to PROMIS scales. Data were collected online from a general population sample (N=1000). Items from the rehabilitation measures and their corresponding PROMIS short forms were administered to facilitate item linkage.

Interventions: Not applicable.

Main outcome measures: WHODAS 2.0, IRES-3, HEALTH-49, and PROMIS scales.

Results: Overall, 96 of 171 outcome items (56%) from the legacy measures and 1 additional IRES-3 item were mapped to 9 PROMIS domains, including pain interference, physical function, dyspnea, fatigue, depression, anxiety, cognitive function, ability to participate in social roles and activities, and satisfaction with participation in social roles and activities. Ninety-five items fulfilled the linking assumptions of construct similarity, unidimensionality, and measurement invariance. The legacy items were successfully calibrated on the corresponding PROMIS metrics using graded-response models. The range and precision of the measures varied, depending on the number of items in each domain. Domains that were assessed with 4 or more items achieved sufficient reliability for group-based analyses. Crosswalk tables were created for each measure and domain. We discussed the reasons for and implications of the fact that the rehabilitation measures were only partially linked to the PROMIS metrics.

Conclusions: The study achieved robust linking between subsets of WHODAS 2.0, IRES-3, HEALTH-49 items, and 9 PROMIS scales.