A cross-sectional comparison of three self-reported functional indices in scleroderma

In scleroderma, outcome measures such as skin score provide only limited information about the functional impact of the disease. The requirement for validated and convenient instruments that reliably reflect disease morbidity is now recognized. This study compares the Disability Index of the Health Assessment Questionnaire (HAQ-DI) with two more recently developed scleroderma-specific tools: scleroderma-visual analogue scales (scleroderma-VAS) and the UK scleroderma Functional Score (UKFS). In addition, the use of clinical and laboratory measures as predictors of disease severity have been examined.

One hundred and fifteen consecutive patients were studied. Subjects completed the 20-item HAQ-DI, the scleroderma-VAS and a questionnaire related to hand and muscle function (UKFS). Clinical details, measurement of maximal hand-spread, fist-closure and investigations for internal organ involvement were recorded.

Over 68% of patients with diffuse disease had moderate to severe disease on the UKFS, compared with 44% with limited disease. The mean UKFS in diffuse disease was 14.7 (s.d. 9.1) and 10.6 (s.d. 8.5) in the limited subset (P=0.02). The mean HAQ-DI in diffuse disease was 1.23 (s.d. 0.77) and 0.79 (s.d. 0.75) in the limited subset (P=0.005). The HAQ-DI showed significant correlation with UKFS (r=0.9; P < 0.001). Several clinical and laboratory measures were associated with higher HAQ-DI and UKFS.

This is the first comparative study of the UKFS and the HAQ-DI. These data show a strong correlation between assessment methods. Higher scores correlated with clinical and laboratory indicators of severe disease. Used together, these inexpensive tools assess general and organ-specific symptoms, as well as functional limitation.