Hip flexion weakness is associated with impaired mobility in oculopharyngeal muscular dystrophy: A retrospective study with implications for trial design

Sarah Youssof, Ronald Schrader, David Bear, Leslie Morrison

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

Oculopharyngeal muscular dystrophy (OPMD) is a rare myopathy for which validated outcome measures are lacking, posing a barrier to clinical trials. Our goal was to identify factors associated with impaired mobility in OPMD in order to guide development of surrogate endpoints in future clinical trials. One hundred forty-four individuals with OPMD were included in this retrospective, single-center study. We made novel use of parametric time-to-event analysis to model age at initial use of assistive device for ambulation. We hypothesized that limb weakness and other markers of disease severity are associated with earlier use of assistive devices. 23.6% of individuals (34/144) progressed to use of assistive devices (mean age 66.0 ± 9.6 y). Earlier age at assistive device was associated with hip flexion Medical Research Council grade ≤3 (. p <. 0.0001), earlier disease onset (. p <. 0.0001), and lack of blepharoptosis surgery (. p = 0.011). Markers of dysphagia severity were not associated with earlier progression to assistive devices. Our study is the first to show a statistical association between hip flexion weakness and impaired mobility in OPMD, indicating that hip flexion strength could be explored as a surrogate endpoint for use in clinical trials. Since severity of disease features may be discordant within individuals, composite outcome measures are warranted.

Original languageEnglish (US)
Pages (from-to)238-246
Number of pages9
JournalNeuromuscular Disorders
Volume25
Issue number3
DOIs
StatePublished - Mar 1 2015
Externally publishedYes

Keywords

  • Mobility impairment
  • Natural history
  • Oculopharyngeal muscular dystrophy
  • Outcome measures
  • Time-to-event analysis

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health
  • Neurology
  • Clinical Neurology
  • Genetics(clinical)

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