Psychometric evaluation of a patient-reported outcome measurement information system for use in Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is a rare disease that causes muscle weakness and impairs an individual's ability to move. DMD mainly affects males, with symptoms getting worse over time. Healthcare professionals use patient-reported outcomes (questionnaires filled out by patients or their caregivers about the patient's health status) to better understand the impact of a disease from the patient's point of view. When patients are too young to report their own symptoms or status, caregivers may answer on their behalf using proxy versions of the questionnaires.

The Patient-Reported Outcomes Measurement Information System Parent Proxy (PROMIS PP) Mobility item bank is a generic questionnaire that contains 23 items aimed at assessing a patients' ability to move. In this study, the goal was to evaluate how well the PROMIS PP Mobility item bank can assess the ability to move in ambulatory males with DMD.

The PROMIS PP Mobility item bank was completed by caregivers of males between 4 years and 12 years of age who have DMD. The study utilized a Rasch analysis, which is a method used to evaluate how well a questionnaire works and how it may be improved for the disease being studied.

The Rasch analysis identified several items from the PROMIS PP Mobility item bank that were not relevant for measuring mobility in the population of patients with DMD. In addition, the analysis identified some response options that could be regrouped to make the item bank more reliable and precise in assessing mobility in males with DMD. This resulted in a customized PROMIS PP Mobility item bank that is able to differentiate between patients with different mobility levels. This customized PROMIS PP Mobility item bank may be helpful for healthcare professionals in assessing mobility in males with DMD and may also be useful in both clinical research and guiding clinical care.