Article

The purpose of this study was to test the cross-sectional and longitudinal construct validity of
the disability-specific short forms of the Symptom Inventory for multiple sclerosis, to compare its internal consistency reliability and construct validity
with those of the original (1999) 29-item short form of the Symptom Inventory,
and to provide for the new disability-specific short forms interpretation metrics
for use in sample size calculation for future research.
DESIGN: A Web-based
longitudinal study, with data collected at baseline and 6 months after baseline.
Correlations evaluated the overlap among disease-specific and generic
patient-reported outcome measures. Responsiveness was assessed by using symptom
transition scores and modified standardized response means. Interpretation
guidelines were provided by using Cohen's effect size and crosswalks to the
disease-specific and generic quality-of-life measures. SETTING: National Multiple
Sclerosis Registry. PARTICIPANTS: People with multiple sclerosis (N=1142) who
participated in the North American Research Committee on Multiple Sclerosis
Registry. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The Symptom
Inventory; the disease-specific Performance Scales and the Patient-Determined
Disease Steps; the generic Short Form 12. RESULTS: The Symptom Inventory
evidenced convergent and divergent validity, and the disability-specific short
forms evidenced similar psychometric performance as the 1999 short form but had
slightly better alpha reliability. They also evidenced moderate responsiveness to
clinically important change, with more responsiveness among those with mild and
moderate disabilities than among those with severe disabilities. Effect sizes
were larger among patients who reported symptom improvement, rather than
deterioration, suggesting that the tool would be more useful in clinical research
focused on testing whether an intervention improves symptom experience,
particularly for patients with mild and moderate disabilities. Crosswalks
provided graphic and numeric links between the Symptom Inventory and other
patient-reported outcomes. CONCLUSIONS: The Symptom Inventory can be useful for
elucidating the patient's experience, but it varies considerably across and
within disability groupings. Directions for future research are discussed.
CI - Copyright (c) 2012 American Congress of Rehabilitation Medicine. Published by
Elsevier Inc. All rights reserved.

Langue : ANGLAIS