Inclusion body myositis functional rating scale: a reliable and valid measure of disease severity

Muscle Nerve. 2008 Apr;37(4):473-6. doi: 10.1002/mus.20958.


We developed a disease-specific, 10-point functional rating scale for patients with inclusion body myositis (IBMFRS). The IBMFRS was utilized as a secondary outcome measure in a multicenter pilot trial of the clinical safety and tolerability of high-dose beta interferon-1a. In this trial, 28 IBM patients completed the IBMFRS at baseline and monthly for 6 months. The IBMFRS showed statistically significant correlations (P < 0.001) with maximal voluntary isometric contraction, manual muscle testing, handgrip dynamometry, and the amyotrophic lateral sclerosis (ALS) functional rating scale (ALSPRS). Compared to these other outcome measures, the IBMFRS was also the most sensitive measure of change over the course of the study.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial
  • Validation Study

MeSH terms

  • Activities of Daily Living
  • Disability Evaluation*
  • Humans
  • Myositis, Inclusion Body / physiopathology*
  • Pilot Projects
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Severity of Illness Index*