Abstract: Does Incorporation of Aids and Devices Make a Difference in the Score of the Health Assessment Questionnaire–Disability Index? Analysis from a Scleroderma Clinical Trial

Does Incorporation of Aids and Devices Make a Difference in the Score of the Health Assessment Questionnaire–Disability Index? Analysis from a Scleroderma Clinical Trial

DINESH KHANNA, PHILIP J. CLEMENTS, ARNOLD E. POSTLETHWAITE, and DANIEL E. FURST, for the Scleroderma Collagen Type 1 Study Group

ABSTRACT.

Objective. The Health Assessment Questionnaire-Disability Index (HAQ-DI) is a commonly used musculoskeletal-targeted measure in systemic sclerosis (SSc). We assessed if HAQ-DI scores are different when calculated with and without aids/devices, and if apparent responsiveness changes when scored in these 2 ways.

Methods. We used data from a placebo-controlled clinical trial in diffuse SSc. Baseline HAQ-DI total score was calculated with and without aids/devices and compared using Student's t-test. We also classified the HAQ-DI scores into no-to-mild disability (0.00–1.00), moderate disability (1.01–2.00), and severe disability (2.01–3.00). Responsiveness to change was evaluated using the effect size (ES).

Results. The mean (SD) baseline HAQ-DI score was 1.33 (0.68) with aids/devices compared to HAQ-DI score 1.16 (0.70) without aids/devices (p = 0.03). When the baseline HAQ-DI score was categorized into no-to-mild, moderate, and severe disability, the proportion of patients in the no-to-mild disability (29% with aids/devices vs 44% without aids/devices) and moderate disability (59% with aids/devices vs 45% without aids/devices) groups were statistically different (p < 0.001). The ES was similar between the 2 groups (ES = 0.01 and 0.02 with and without aids/devices).

Conclusion. This analysis suggests a shift from no-to-mild disability to moderate disability when aids/devices are incorporated in total HAQ-DI score. Future clinical trials in SSc should explicitly state whether HAQ-DI score was calculated using aids/devices. (First Release Dec 15 2007; J Rheumatol 2008;35:466-8)

Key Indexing Terms:

HEALTH ASSESSMENT QUESTIONNAIRE–DISABILITY INDEX
SYSTEMIC SCLEROSIS
CLINICAL TRIAL

From the Division of Rheumatology, Department of Medicine, David Geffen School of Medicine, University of California at Los Angeles; Department of Health Services, School of Public Health, University of California at Los Angeles, Los Angeles, California; and Division of Rheumatology, Department of Internal Medicine, University of Tennessee, Memphis, Tennessee.

Dr. Khanna was supported by the Scleroderma Foundation (New Investigator Award), a National Institutes of Health Award (NIAMS K23 AR053858-01A1), and a grant from the Scleroderma Clinical Trial Consortium. Dr. Furst and Dr. Postlethwaite are partially supported by the Scleroderma Foundation (Established Investigator Award). The Oral Type 1 Collagen in Scleroderma Study was sponsored by the National Institutes of Health (NIH)/National Institute of Arthritis and Musculoskeletal and Skin Diseases (grant N01AR092242).

D. Khanna, MD, MSc, Division of Rheumatology, Department of Medicine, Department of Health Services, School of Public Health, University of California; P.J. Clements, MD, MPH, Division of Rheumatology, Department of Medicine, David Geffen School of Medicine; A.E. Postlethwaite, MD, Division of Rheumatology, Department of Internal Medicine, University of Tennessee; D.E. Furst, MD, Division of Rheumatology, Department of Medicine, David Geffen School of Medicine, University of California.

Address reprint requests to Dr. D. Khanna, Division of Rheumatology, Department of Medicine, David Geffen School of Medicine, 1000 Veterans Avenue, Room 32-59 Rehabilitation Building, Los Angeles, CA 90095. E-mail: dkhanna@mednet.ucla.edu

Accepted for publication October 19, 2007.