Psychometric characteristics of the short form 36 health survey and functional assessment of chronic illness Therapy-Fatigue subscale for patients with ankylosing spondylitis

Revicki, Rentz, Luo, Wong

Description

We evaluated the psychometric characteristics of the Short Form 36 (SF-36) Health Survey and the Functional Assessment of Chronic Illness Therapy (FACIT)-Fatigue subscale in patients with ankylosing spondylitis (AS). Methods We analyzed clinical and patient-reported outcome (PRO) data collected during 12-week, double-blind, placebo-controlled periods of two randomized controlled trials comparing adalimumab and placebo for the treatment of active AS. The Bath Ankylosing Spondylitis Disease Activity Index, Bath Ankylosing Spondylitis Functional Index, and other clinical measures were collected during the clinical trial. We evaluated internal consistency/reliability, construct validity, and responsiveness to change for the SF-36 and FACIT-Fatigue. Results The SF-36 (Cronbach alpha, 0.74-0.92) and FACIT-Fatigue (Cronbach alpha, 0.82-0.86) both had good internal consistency/reliability. At baseline, SF-36 and FACIT-Fatigue scores correlated significantly with Ankylosing Spondylitis Quality of Life scores (r = -0.36 to -0.66 and r = -0.70, respectively; all p < 0.0001). SF-36 scores varied by indicators of clinical severity, with greater impairment observed for more severe degrees of clinical activity (all p < 0.0001). FACIT-Fatigue scores correlated significantly with SF-36 scores (r = 0.42 to 0.74; all p < 0.0001) and varied by clinical severity (p < 0.05 to p < 0.0001). Conclusions The SF-36 is a reliable, valid, and responsive measure of health-related quality of life and the FACIT-Fatigue is a brief and psychometrically sound measure of the effects of fatigue on patients with AS. These PROs may be useful in evaluating effectiveness of new treatments for AS. Trial Registration ClinicalTrials.gov: NCT00085644 and NCT00195819

Sujets

• Ankylosing spondylitis
• Reliability
• Validity

Informations

• Publié par: biomed
• Publié le: 01 janvier 2011
• Nombre de lectures: 10
• Langue: English

Extrait

Revickiet al.Health and Quality of Life Outcomes2011,9:36 http://www.hqlo.com/content/9/1/36

R E S E A R C HOpen Access Psychometric characteristics of the short form 36 health survey and functional assessment of chronic illness TherapyFatigue subscale for patients with ankylosing spondylitis 1* 12 3 Dennis A Revicki, Anne M Rentz , Michelle P Luoand Robert L Wong

Abstract Background:We evaluated the psychometric characteristics of the Short Form 36 (SF36) Health Survey and the Functional Assessment of Chronic Illness Therapy (FACIT)Fatigue subscale in patients with ankylosing spondylitis (AS). Methods:We analyzed clinical and patientreported outcome (PRO) data collected during 12week, doubleblind, placebocontrolled periods of two randomized controlled trials comparing adalimumab and placebo for the treatment of active AS. The Bath Ankylosing Spondylitis Disease Activity Index, Bath Ankylosing Spondylitis Functional Index, and other clinical measures were collected during the clinical trial. We evaluated internal consistency/reliability, construct validity, and responsiveness to change for the SF36 and FACITFatigue. Results:The SF36 (Cronbach alpha, 0.740.92) and FACITFatigue (Cronbach alpha, 0.820.86) both had good internal consistency/reliability. At baseline, SF36 and FACITFatigue scores correlated significantly with Ankylosing Spondylitis Quality of Life scores (r = 0.36 to 0.66 and r = 0.70, respectively; all p < 0.0001). SF36 scores varied by indicators of clinical severity, with greater impairment observed for more severe degrees of clinical activity (all p < 0.0001). FACITFatigue scores correlated significantly with SF36 scores (r = 0.42 to 0.74; all p < 0.0001) and varied by clinical severity (p < 0.05 to p < 0.0001). Conclusions:The SF36 is a reliable, valid, and responsive measure of healthrelated quality of life and the FACIT Fatigue is a brief and psychometrically sound measure of the effects of fatigue on patients with AS. These PROs may be useful in evaluating effectiveness of new treatments for AS. Trial Registration:ClinicalTrials.gov: NCT00085644 and NCT00195819 Keywords:Ankylosing spondylitis, Healthrelated quality of life, Physical and mental health, Reliability, Validity

Background Ankylosing spondylitis (AS) is a chronic and progressive inflammatory disorder that primarily affects the axial skeleton, sacroiliac joints of the pelvis, and thoracic cage [1,2]. Patients experience pain, joint stiffness, and the eventual loss of spinal mobility with disease progression. Patients with AS frequently experience impaired physi cal function and wellbeing, require time away from work because of disability, and suffer from diminished

* Correspondence: [e-mail] 1 Outcomes Research, United BioSource Corporation, Bethesda, MD, USA Full list of author information is available at the end of the article

healthrelated quality of life (HRQOL) [37]. The impact of AS on functioning and everyday life varies by patient, but most patients typically have a broad spectrum of impairments, including the physical, psychological, and social domains of HRQOL. Patientreported outcomes (PROs), including HRQOL assessments, symptom scales, and other measures, are increasingly used to evaluate the healthrelated out comes of rheumatology treatments from the patient per spective. PROs are incorporated into clinical studies of patients with AS and provide important assessments of functioning and wellbeing that complement and expand

© 2011 Revicki et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.