The Disability Index of the Health Assessment Questionnaire is a predictorand correlate of outcome in the high-dose versus low-dose penicillamine insystemic sclerosis trial

Objective. To explore the clinical implications of a score of greater than or equal to1.0 on the Disability Index of the Health Assessment Questionnai re (HAQ DI) at the first patient visit, and to examine the implications of improvement in HAQ DI score over 2 years in a cohort of systemic sclerosis (SSc) patients with diffuse cutaneous scleroderma. Methods. SSc skin and visceral involvement was assessed in 134 SSc patients with diffuse scleroderma (mean +/- SD disease duration of 10 +/- 4 months) when they entered a multicenter drug trial and again 2 years later. Mortal ity and the occurrence of scleroderma renal crisis were assessed for a mean +/- SD of 4.0 +/- 1.1 years. Logistic and linear regression analyses were used to examine the relationship of the baseline RAQ DI score to morbidity, mortality, and visceral involvement, as well as the relationship of change s in the HAQ DI score to changes in physical examination, laboratory, and f unctional variables over 2 years. Results. A baseline HAQ DI score of greater than or equal to1.0 was predict ive of mortality (odds ratio 3.22, 95% confidence interval 1.097-9.468) ove r 4 years. Multivariate linear regression demonstrated that a model which i ncluded the erythrocyte sedimentation rate at baseline (P = 0.005) and chan ges at 2 years in the swollen joint count (P = 0.002), total skin score (P = 0.005), and white blood cell count (P = 0.005) best explained the change in HAQ DI score over 2 years (R-2 = 0.528). The HAQ DI score and total skin score at baseline were highly correlated (correlation coefficient 0.368), as were changes in the HAQ DI score and the total skin score over 2 years ( correlation coefficient 0.492). Although the HAQ DI score was heavily influ enced by hand dysfunction at baseline and at 2 years, improvement (reductio n) in the HAQ DI score over 2 years was related to factors other than hand dysfunction. Conclusion. A baseline HAQ DI score of greater than or equal to1.0 predicte d mortality over 4 years. Improvement in the HAQ DI score in these patients with diffuse scleroderma was associated with improvement in skin thickenin g, hand function, oral aperture, lung function, signs of arthritis, serum c reatinine level, and the investigator's global assessment of improvement. T he HAQ DI is a self-administered questionnaire that SSc patients can comple te easily and rapidly and that gives the practicing physician important inf ormation about prognosis, patient status, and changes in disease course ove r time.