Psychometric evaluation of the PROMIS parent proxy mobility item bank for use in Duchenne muscular dystrophy.

Only caregivers of ambulatory boys aged 4 to 12 years at one neuromuscular clinic were included, so it may not apply to girls, older children, non-ambulatory patients, or other care settings. The analysis excluded patients aged 13 years and older because loss of ambulation was likely, so the measure was not tested near the transition to wheelchair use. Sociodemographic information was not collected to avoid identifying patients, so the authors could not check whether items behave differently across background groups. Differential item functioning could not be properly investigated, and the age-group signal for one item was not treated as definitive. The measure had a gap at high mobility levels, so it may not differentiate children with the best mobility. No comparison with directly relevant PROMIS parent proxy mobility literature was available.

The authors declared no conflicts of interest. The work was funded by Sarepta Therapeutics, Inc.

Do not conclude that the revised measure is ready for all children with Duchenne muscular dystrophy. It was analysed in one clinic in ambulatory boys aged 4 to 12 years, and the authors call for validation in another independent sample.