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Responsiveness of the SF-36 and the Health Assessment Questionnaire Disability Index in a Systemic Sclerosis Clinical Trial
DINESH KHANNA, DANIEL E. FURST, PHILIP J. CLEMENTS, GRACE S. PARK, RON D. HAYS, JEONGLIM YOON, JOSEPH H. KORN, PETER A. MERKEL, NAOMI ROTHFIELD, FREDRICK M. WIGLEY, LARRY W. MORELAND, RICHARD SILVER, VIRGINIA D. STEEN, MICHAEL WEISMAN, MAUREEN D. MAYES, DAVID H. COLLIER, THOMAS A. MEDSGER Jr, and JAMES R. SEIBOLD, for the Relaxin Study Group and the Scleroderma Clinical Trials Consortium
ABSTRACT.
Methods. A phase 2/3, multicenter, prospective, placebo controlled trial was conducted to evaluate human recombinant relaxin treatment in patients with diffuse SSc over 24 weeks. At baseline, subjects had stable, moderately severe, diffuse SSc of disease duration ≤ 5 years, modified Rodnan skin score ≥ 20, serum creatinine < 2.0 mg/dl, percentage forced vital capacity (% FVC) predicted ≥ 50%, and % DLCO predicted ≥ 40% and were not receiving concomitant disease modifying therapies. Internal consistency reliability of multi-item scales was estimated using Cronbach's alpha. Responsiveness to change of the SF-36 and HAQ-DI was computed between Weeks 0 and 24. Subjects were classified as unchanged or having a meaningful change in 4 different external measures: Change in (1) skin score ≥ 30%; (2) % FVC predicted of ≥ 15%; (3) self-reported patient global assessment by visual analog scale (VAS) ≥ 20%; and (4) physician global assessment by VAS of ≥ 20%. Responsiveness indices were computed and Cohen's effect size criteria were used to assess the magnitude of change. Results. A total of 239 patients participated in this trial, with 196 completing the 24 week trial. Cronbach's alpha for the SF-36 scales ranged from 0.76 to 0.93 and for the HAQ-DI ranged from 0.69 to 0.91 (good to excellent). The SF-36 had a larger magnitude of responsiveness in overall disease (patient and physician global assessment) compared to the HAQ-DI, while the HAQ-DI had a larger magnitude of responsiveness in clinical measures (i.e., change in skin score and % FVC predicted) than the SF-36. Conclusion. These data support inclusion of both the SF-36 and HAQ-DI as outcome measures in future clinical trials of diffuse SSc. (J Rheumatol 2005;32:832-40) Key Indexing Terms:
HEALTH RELATED QUALITY OF LIFE
From the Division of Rheumatology, Department of Medicine, and Division of General Internal Medicine and Health Services Research, David Geffen School of Medicine, Los Angeles, California; Section of Rheumatology, Boston University, Boston, Massachusetts; University of Connecticut Health Center, Farmington, Connecticut; Johns Hopkins University, Baltimore, Maryland; University of Alabama at Birmingham, Birmingham, Alabama; University of South Carolina, Charleston, South Carolina; Division of Rheumatology, Georgetown University Medical Center, Washington, DC; Cedars-Sinai Medical Center, Los Angeles, California; University of Texas Health Science Center, Houston, Texas; University of Colorado, Denver, Colorado; University of Pittsburgh, Pittsburgh, Pennsylvania; and University of Michigan Scleroderma Program, Ann Arbor, Michigan, USA. Dr. D. Khanna was supported by the Arthritis and Scleroderma Foundations (Physician Scientist Development Award) and a grant from the Scleroderma Clinical Trial Consortium. Dr. R.D. Hays was supported in part by the UCLA/DREW Project EXPORT, National Institutes of Health, National Center on Minority Health & Health Disparities (P20-MD00148-01) and the UCLA Center for Health Improvement in Minority Elders/Resource Centers for Minority Aging Research, National Institutes of Health, National Institute of Aging (AG-02-004). Dr. P.A. Merkel was supported in part by a Mid-Career Development Award in Clinical Investigation (NIH-NIAMS: K24 AR2224-01A1) and the National Center for Research Resources (NCRR), Boston University General Clinical Research Center Program Grant (NIH-NCRR: MO 1RR00533). The clinical trial was supported by Connetics Corporation, Palo Alto, California. D. Khanna MD, MSc, Assistant Professor of Medicine; D.E. Furst, MD, Professor of Medicine; P.J. Clements, MD, MPH, Professor of Medicine; G.S. Park, MPH, Biostatistician; J. Yoon, BA, Master's Student in Biostatistics, Division of Rheumatology, Department of Medicine, David Geffen School of Medicine; R.D. Hays, PhD, Professor of Medicine, Division of General Internal Medicine and Health Services Research, David Geffen School of Medicine; J.H. Korn, MD, Professor of Medicine; P.A. Merkel, MD, MPH, Associate Professor of Medicine, Section of Rheumatology, Boston University; N. Rothfield, MD, Professor of Medicine, University of Connecticut Health Center; F.M. Wigley, MD, Professor of Medicine, Johns Hopkins University; L.W. Moreland, MD, Professor of Medicine, University of Alabama at Birmingham; R. Silver, MD, Professor of Medicine, University of South Carolina; V.D. Steen, MD, Professor of Medicine, Division of Rheumatology, Georgetown University Medical Center; M. Weisman, MD, Professor of Medicine, Cedars-Sinai Medical Center; M.D. Mayes, MD, MPH, Professor of Medicine, University of Texas Health Science Center; D.H. Collier, MD, Professor of Medicine, University of Colorado; T.A. Medsger Jr, MD, Professor of Internal Medicine, University of Pittsburgh; J.R. Seibold, MD, Professor of Internal Medicine, University of Michigan Scleroderma Program. The following investigators also participated in the study: M. Ellman, MD, University of Chicago, Chicago, IL; Y. Kim, MD, Stanford University, Stanford, CA; G.S. Firestein, MD; A.F. Kavanaugh, MD, University of California, San Diego, CA; M.E. Csuka, MD, Medical College of Wisconsin, Milwaukee, WI; R. Simms, MD, Boston University Medical Center, Boston, MA; V.M. Hsu, University of Medicine and Dentistry, Scleroderma Program, Newark, NJ. Address reprint requests to Dr. D. Khanna, Division of Immunology, Department of Medicine, University of Cincinnati, PO Box 670563, Cincinnati, OH 45267-0563. E-mail: dinesh.khanna@uc.edu Accepted for publication December 20, 2004. |