Background/Purpose:

Patients with anti-PM-Scl antibody (PM-Scl) can present with several different phenotypes: polymyositis (PM), dermatomyositis (DM), systemic sclerosis (SSc), scleromyositis, or sclero-dermatomyositis. Pulmonary arterial hypertension (PAH) may be a disease manifestation of patients with PM-Scl but the association has not been rigorously examined and the association between its clinical manifestations and PAH is not clear, especially with PAH confirmed on right heart catheterization (RHC).

The association of PAH in systemic sclerosis is well established. Recent discoveries of effective medications to treat PAH, especially in patients with SSc have been encouraging and have important implications for other “autoimmune rheumatic disease”-associated PAH. It is not clear whether similar recommendations should apply to patients with PM-Scl.

Methods:

All patients screened for PM-Scl between October 1999 and April 2014 were evaluated through our electronic medical record (EMR) system and patients with positive PM-Scl were identified. The patients’ demographics, rheumatologic diagnoses (PM, DM, SSc, scleromyositis, or sclero-dermatomyositis), co-existing auto-antibodies, RHC variables, skin manifestations related with dermatomyositis, and presence of CT defined interstitial lung disease (ILD) were extracted from their EMR retrospectively. The primary outcome of this study was to compare the prevalence of RHC-confirmed PAH among patients with PM-Scl to that in the general population and also to that in SSc. The secondary outcomes were to explore possible predictors of PAH among these patients including presenting phenotypes or co-existing auto-antibodies.

Results:

PM-Scl was detected in 42 patients; 32 (76.2%) were female. Mean age at diagnosis of their rheumatologic condition was 45.1 years and that of PM-Scl detection was 51 years. Five patients had RHC proven PAH [11.9% (95% confident interval 4.0% – 25.6%)], of whom 2 had moderate (mean pulmonary artery pressure (PAP) 41-55 mmHg) and 3 had mild PAH (mean PAP 25-40 mmHg). Compared to a previously documented prevalence of PAH in the general population of 0.0015%, this study found a significantly higher rate of PAH in patients with PM-Scl (1). However, the rate (11.9%) did not differ significantly from a previously documented prevalence of PAH in SSc patients (7.8%) (2). Of all PM-Scl positive patients 27 had ILD, of whom 4 also had PAH. There was a significant association between phenotype and PAH (P=0.003). In our cohort, all patients with PAH were associated with either DM or sclero-dermatomyositis phenotypes. There was no significant association of co-existing autoantibodies in these PAH patients.

Conclusion:

Patients with PM-Scl have a higher prevalence of PAH than that in the general population, and should be screened for it at baseline and periodically thereafter. In our cohort PAH was seen in those presenting with a clinical phenotype of DM or sclero-dermatomyositis.

Reference

(1) Humbert M et al. Am J Respir Crit Care Med. 2006; 173(9):1023-1030.

(2) Hachulla et al. Arthritis Rheum. 2005; 52(12):3792-3800.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/pulmonary-arterial-hypertension-in-patients-with-anti-pm-scl-antibody/