Psychometric validation of a patient-reported measure of physical functioning in sporadic inclusion body myositis.

Journal Article (Journal Article)

INTRODUCTION: To assess self-reported physical functioning in patients with sporadic inclusion body myositis (sIBM), the sIBM Physical Functioning Assessment (sIFA) was developed. This research establishes the validity, reliability, and responsiveness of the sIFA in patients with sIBM. METHODS: Data from 3 small, noninterventional, observational studies were analyzed. Several measures of physical function were included to assess validity. Reliability (Cronbach alpha, test-retest intraclass correlations), construct validity (correlations, analyses of variance), and responsiveness (effect size estimates) were evaluated. RESULTS: Cronbach alphas (range = 0.86-0.91) and test-retest reliability (0.91) were highly satisfactory. Correlations with other measures provided evidence of convergent validity. sIBM patients able to walk without assistive devices scored significantly better on the sIFA (means = 36.0-47.05) than those who required power mobility or wheelchairs (means = 54.9-71.5), demonstrating the discriminating ability of the sIFA. Effect size estimates of responsiveness suggested mild functional progression. CONCLUSIONS: Psychometric analyses of the sIFA demonstrate satisfactory reliability, validity, and responsiveness. Muscle Nerve 54: 658-665, 2016.

Full Text

Duke Authors

Cited Authors

  • Williams, V; Coles, T; Gnanasakthy, A; Demuro, C; Yarr, S; Williams, N; Lowes, L; Alfano, L; Tseng, B

Published Date

  • October 2016

Published In

Volume / Issue

  • 54 / 4

Start / End Page

  • 658 - 665

PubMed ID

  • 26872636

Electronic International Standard Serial Number (EISSN)

  • 1097-4598

Digital Object Identifier (DOI)

  • 10.1002/mus.25080


  • eng

Conference Location

  • United States