Background/Purpose: Systemic sclerosis (SSc) is an autoimmune disorder with excessive fibrosis and vasculopathy. While typically non-inflammatory, frank vasculitis can complicate SSc. Concomitant SSc with ANCA-associated vasculitis (AAV), including granulomatosis with polyangiitis, microscopic polyangiitis, eosinophilic granulomatosis with polyangiitis, or large vessel vasculitis (LVV), including giant cell arteritis and Takayasu’s arteritis, is exceedingly rare yet carries high morbidity risk. Few cases describe pulmonary arterial hypertension (PAH) in these cases of overlap. In this study, we examine the association between SSc and development of both AAV and LVV. Then, we examine whether the presence of PAH in SSc patients is associated with the development of AAV and LVV.

Methods: This retrospective analysis utilized real-world dynamic data from TriNetX clinical research platform, representing over 124 million patients in the Research network. We identified 67,757 patients with SSc and 122,693,631 controls without SSc. AAV and LVV prevalence and relative risk (RR) with 95% confidence interval (CI) were assessed between groups. Chi-square test was used to compare AAV and LVV prevalence between groups and significance was defined as p-value < 0.05. Subgroup analysis for patients with SSc and PAH was carried out. Participants were identified based on International Classification of Diseases, 10th Revision, Clinical Modification (ICD-10-CM) diagnosis codes.

Results: Demographics of SSc cohort included: mean age 63, standard deviation (SD) 17, female 80.14%, male 16.92, unknown gender 2.94%. Demographics of controls without SSc cohort included: mean age 46, SD 25, female 52.31%, male 45.34%, unknown gender 2.35%.

The prevalence of AAV was 35.72/10,000 patients with SSc compared to 0.013/10,000 patients (p-value < 0.0001) in controls. The prevalence of LVV was 41.9/10,000 patients with SSc compared to 0.031/10,000 patients in controls (p-value < 0.0001). Among patients with SSc, we identified 9,291 patients with PAH and 55,226 patients without. The prevalence AAV in patients with SSc and PAH was 39 (0.004) compared to 183 (0.003) in the control group (p-value 0.2). The prevalence of LVV in patients with SSc and PAH was 32 (32/9,291) compared to 203 (0.004) in the control group (p-value 0.7). The associations between PAH in patients with SSc with the development of AAV (RR 1.27, 95% CI 0.9 – 1.8) and LVV (RR 0.9, 95% CI 0.6 – 1.4) were statistically insignificant, respectively.

Conclusion: Patients with SSc have a statistically significant association with the development of both AAV and LVV. However, the presence of PAH in these patients with SSc does not have a statistically significant association with the development of AAV and LVV. SSc, AAV and LVV all carry a risk of significant multi-organ involvement and morbidity. Both AAV and LVV in SSc portend worse prognoses with higher mortality risk compared to those without vasculitic overlap. Prompt recognition and management of this unusual clinical overlap is crucial given the potential for life-threatening complications. Monitoring for the vascular manifestation of PAH in patients with SSc does not appear to be an effective screening tool for AAV and LVV.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/association-of-systemic-sclerosis-with-anca-associated-vasculitis-and-large-vessel-vasculitis-impact-of-pulmonary-arterial-hypertension/