The effect of hydroxychloroquine on activities of daily living and hand function in systemic sclerosis: results from an analysis of the EUSTAR cohort

Background: To evaluate the use of hydroxychloroquine (HCQ) and its impact on the Health Assessment Questionnaire disability index(HAQ-DI) and the Cochin Hand Function Status(CHFS) in a large Systemic Sclerosis (SSc) cohort. Methods: SSc patients from the European Scleroderma Trials and Research (EUSTAR) database treated with HCQ for at least 6 months were evaluated and compared to a matched group of SSc patients not using HCQ. Demographic and clinical data, concomitant drugs, HAQ-DI and CHFS (at least 2 evaluations) were recorded and were the outcome variables of interest. Statistical analysis was performed using propensity score matching for age, gender, disease duration, corticosteroids, immunosuppressives, vasoactive drugs in a 3:1 control: HCQ ratio. Standard descriptive statistics and Student’s t-test and Chi-square test were used to assess the propensity-matched groups. Results: Out of 17,805 SSc patients evaluated, 468 (2.6%) used HCQ and constituted the HCQ group. Among them, 50 (10.7%) had at least a baseline and follow-up HAQ-DI evaluation and 44 (9.4%) had at least a baseline and follow-up CHFS evaluation. Propensity matching assured that patients were matched for female gender (HCQ vs. control 92.0% vs. 85.3%), mean age (49.8 vs. 50.0 years) disease duration (8.3 vs. 9.1 years), limited disease (55.3 vs. 62.6%) as well as background medications (all P > 0.1). We did not find any significant differences among the two groups in the change of HAQ-DI or CHFS, over up to 365 days (all P > 0.05). Conclusions: Results from the EUSTAR registry showed that HCQ was used by 2.6% of SSc patients. HCQ use did not improve the HAQ-DI, or CHFS when comparing HCQ users to non-HCQ users.