Background/Purpose: ESOS (European Scleroderma Observational Study) was a prospective observational study of 326 patients with early diffuse cutaneous systemic sclerosis (dcSSc) from 50 centres. Here we describe the burden of disease in terms of disability and fatigue in this very early disease cohort (median disease duration 11.9 months), and explore disease features that associate with this burden.

Methods: Patients completed questionnaires at study entry and at 12 months: the Scleroderma Specific Health Assessment Questionnaire (sHAQ, including HAQ-DI disability index), Functional Assessment of Chronic Illness Therapy [FACIT]-fatigue, the Short Form 36 [SF36] and the Cochin Hand Function Scale (CHFS). Covariates examined included the modified Rodnan skin score (mRSS) and other parameters listed in Table 1. The distribution of the HAQ-DI, fatigue and hand function scores was compared between levels of categorical variables using Kruskal-Wallis’ test and correlations with other continuous variables were assessed using Spearman’s coefficient (ρ). For continuous variables, correlations between 12-month changes were also computed.

Results: Baseline scores of HAQ-DI, FACIT and CHFS, and associates are shown in Table 1. High levels of skin fibrosis (mRSS) were associated with poor hand function (ρ=0.35) and high HAQ-DI scores (ρ=0.34). The median CHFS (0-90 scale) and HAQ-DI (0-3 scale) scores were higher by 8.5 and 0.6 units (indicating poorer hand function and increased disability) in patients with current digital ulcers. The median HAQ-DI score was higher by one unit in patients with muscle involvement, and was also higher in patients with lung fibrosis and heart involvement. Cardiac, pulmonary and renal involvement were each associated with higher levels of fatigue. Patients currently or previously on corticosteroids had more disability and fatigue than patients who had never been prescribed these. As anticipated, HAQ-DI, FACIT, CHFS and SF36 scores were all highly correlated. The 12-month change in HAQ-DI had a strong association with the change in hand function (ρ=0.56), and increasing levels of skin fibrosis were correlated with increasing HAQ-DI scores (ρ=0.40).

Conclusion:

1.    ESOS benchmarks the burden of disability in early dcSSc, with high levels of disability and fatigue, and will provide comparative data for future clinical trials.

2.    The degree of disability/fatigue is associated with severity of skin thickening (mRSS), with changes in HAQ-DI over 12 months correlating with changes in mRSS.

3.    Impaired hand function is a major contributor to overall disability.

4.    Disability and fatigue associate with internal organ involvement, and overall (HAQ-DI) and hand disability with digital ulcers. Table 1. Baseline associates of disability, median and interquartile range (for levels within binary variables) and correlations (for pairs of continuous variables).