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.
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).


CONCLUSIONS
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.
Khanna
Dinesh
D
Division of Rheumatology, Department of Medicine, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California, USA. dkhanna@mednet.ucla.edu
Clements
Philip J
PJ
Postlethwaite
Arnold E
AE
Furst
Daniel E
DE
D000203:Activities of Daily Living; D002986:Clinical Trials as Topic; D015331:Cohort Studies; D004185:Disability Evaluation; D006801:Humans; D015203:Reproducibility of Results; D045743:Scleroderma, Diffuse; D012656:Self-Help Devices; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires