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Digital ulcers (DUs) cause significant morbidity in systemic sclerosis (SSc), occurring in 50% of patients with the disease.1 Patients report the impact of Raynaud's phenomenon and DU as worse than lung and gastrointestinal problems associated with SSc.2 The Health Assessment Questionnaire (HAQ)3 score is higher in patients with SSc with DU than in those without DU.4 A subset of the Health Assessment Questionnaire Disability Index (HAQ-DI) has been used for determining hand function,5 which is associated with work disability in patients with SSc.6 The purpose of this study was to determine if the HAQ score improved when a DU healed and if it worsened when a DU occurred.
Data were obtained from Actelion Pharmaceuticals Ltd for this post hoc analysis. All patients participating in the RAndomised Placebo-controlled Investigation of Digital ulcers in Scleroderma (RAPIDS)-1 and -2 trials were included,5 7 which compared bosentan with placebo for the prevention and healing of DUs in SSc. Patients completed the HAQ-DI at each visit including hand function variables (dressing and grooming, hygiene and grip) scored from 0 to 3. RAPIDS-1 was a 16-week randomised controlled trial in patients with SSc who had a DU during the year before enrolment with a 2:1 bosentan to placebo randomisation.5 In RAPIDS-2, patients had at least one DU at baseline, randomisation was 1:1 and duration was 24 weeks.7 Data from the two studies were pooled irrespective of treatment allocation to determine the within-patient differences in the HAQ score between patients with and without DU. Patients (133 in the placebo group, 176 treated with bosentan) were grouped by DU status at baseline and study end into two categories: those with a change in DU status during the study and those without a change in DU status during the study. Baseline characteristics were similar in the two groups. The difference in the HAQ score at baseline and at the end of the study was determined. The results are summarised in table 1.
The group with unchanged DU status reported relatively small changes across all scores. In the group with a change in DU status during the study, HAQ scores were better in those without a DU than in those with a DU.
This study prospectively shows a stable HAQ score if there is no change in DU status and an improved HAQ score in patients with SSc without DU compared with those with DU, although the changes may not have reached the minimally important difference for the HAQ-DI of 0.21 for any group.8 9 If a DU was present at baseline and healed by the time a new DU occurred elsewhere and was present at trial end, this would categorise a patient as having ‘unchanged status’ even if the new ulcer was small or in a different location. However, this was the best way to analyse the data instead of dividing the HAQ at several time points.
Treatment allocation was not taken into consideration in the analysis and may or may not have affected the results. However, the HAQ score did not improve with bosentan in the TRacleer Use in pulmonary arterial hypertension associated with Scleroderma and connective Tissue diseases (TRUST) study.10 Also, in SSc, many other problems can alter hand function including sclerodactyly, swelling, contractures and Raynaud's phenomenon.
This study shows that HAQ can vary with the presence and absence of DU. The subset of the HAQ that is related to hand function is better able to detect the functional impact of DU in patients with SSc.
Acknowledgments
The authors thank the investigators and all members of the steering committees of RAPIDS-1 and RAPIDS-2. They also thank Actelion and all investigators who participated.
Footnotes
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Funding Data for this study were from the RAPIDS-1 and RAPIDS-2 trials funded by Actelion Pharmaceuticals Ltd.
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Competing interests JP has received payment from Actelion Pharmaceuticals Ltd for consultancy.
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Provenance and peer review Not commissioned; externally peer reviewed.