P020 Audit of bosentan use in Rapid Access to Digital Ulcer Clinic (RADUC) in systemic sclerosis: a single-centre experience
Authors: Sobrado Marta , Nerviani Alessandra , Eldaw Tahlil , Cainap Joseph , Denton Christopher P , Ong Voon H 
Published: April 2023

Abstract

Background/Aims
Systemic sclerosis (SSc) is an autoimmune disease characterised by microvascular injury and excessive fibrotic responses. About 55% of SSc patients develop digital ulcers (DUs). The revised “Clinical commissioning policy for the prescription of sildenafil and bosentan for the treatment of digital ulceration in SSc in adults” recommends oral agents, sildenafil and bosentan, before IV-prostanoids. Patients are eligible for bosentan with either severe vasculopathy (causing/threatening tissue loss despite optimal treatment) or ≥ 3 DUs. A dedicated specialist nurse-led Rapid Access to Digital Ulcer clinic (RADUC) is established in our centre to manage SSc patients with DUs. This audit aimed to evaluate the use of bosentan for the treatment of severe DUs in SSc.

Methods
We analysed data from patients who started bosentan between 05-2017 and 09-2022 at our centre. Patients with pulmonary hypertension were excluded. Data were collected at baseline and 6-months after starting bosentan using clinical records/self-completed questionnaires. Quality-of-life was measured with SHAQ 3-domains (1-disability, 2-disability using aids, 3-pain). Data were analysed using Prism v9.4 and expressed as mean±standard deviations. Wilcoxon/Spearman was applied as appropriate. P-values&lt;0.05 were considered significant.

Results
We included 21 patients; 71.4% (15/21) were female with mean age of 49.9 years (25-70). 47.6% (10/21) had limited cutaneous SSc, and mean disease-duration was 16-years (25-44). All patients had severe/≥3 DUs (mean 5 DUs/patient). 20/21 patients started bosentan after inadequate response/intolerance to both sildenafil and iloprost, while 1/21 was iloprost-naïve. On initiation of bosentan, 23.8% (5/21) had stopped sildenafil due to side effects, and 23.8% (5/21) had not received any prostanoids in the preceding 12-months. Within the first 6-months, bosentan was stopped in 3/21 patients either for liver function derangement (2) or non-compliance to blood-monitoring (1), but 2/3 patients restarted it. No other serious adverse events were reported. 6-month data was available for 11/21 patients. Of these, 72.7% (8/11) had reduction of total DUs (mean delta -2.9), whilst 27.3% (3/11) reported new DUs. Overall, the total number of ulcers reduced from 5±2.2 to 2.7±2.2 (p &lt; 0.05). Concomitant sildenafil use did not have any significant effect on new DUs development/DUs reduction. Concerning quality-of-life, 81.8% (9/11) had a documented improvement in at least one domain; 1/11 patients reported worsening in all domains in association with new DUs. We observed a significant reduction in SHAQ2 (7.8±3.9 vs 6.9±2.7, p &lt; 0.05) with a positive correlation between ulcer numbers and the SHAQ2 both recorded at 6-months (r = 0.78, p &lt; 0.05).

Conclusion
Our data suggest that bosentan is well-tolerated and effective in reducing the overall DU burden and improving some of the patient-reported outcomes at 6-months. To date, most patients had already received both sildenafil and IV-prostanoids; however, an increasing number of patients are now initiated on bosentan prior to IV-prostanoids, and this will be audited in the future.
Disclosure
M. Sobrado: None. A. Nerviani: None. T. Eldaw: None. J. Cainap: None. C.P. Denton: None. V.H. Ong: None.