Independent Risk Factors for SLE-Associated PAH Identified

Many patients with systemic lupus erythematosus (SLE) develop lung involvement during the course of their disease. Several clinical and serologic features of SLE have been clinically associated with pulmonary arterial hypertension (PAH). Presence of Raynaud’s phenomenon, anticardiolipin antibodies, and anti-U1 ribonucleoprotein (RNP) antibodies have been shown in prior studies to be independently associated with the development of PAH.¹  

To identify if additional factors were associated with an increased risk for PAH, Ci-Bo Huang, MD, and colleagues from the Peking Union Medical College Hospital, Beijing, China, collected demographic, clinical, and laboratory data for patients with right-heart catheterization (RHC)-confirmed PAH and SLE, and compared their characteristics to patients with SLE, but no PAH, matched for age and gender.²

Researchers analyzed the data from 111 patients with RHC-confirmed PAH and SLE, and found that they had an average age of onset of 34.6 years (± 8.6 years), mean pulmonary arterial pressure (mPAP) of 46.4 mm Hg (± 11.4 mm Hg), cardiac index (CI) 2.7 L/min/m² (± 0.8 L/min/m²), and peripheral vascular resistance (PVR) of 10.5 WU (± 4.8 WU).   Of these patients, 65% were receiving PAH-targeted pharmacotherapy and 46% were classified as World Health Organization PH functional assessment class I or II (WHO Fc I-II), indicating that they either had no symptoms with ordinary activity or symptoms with ordinary activity with slight limitations of physical activity.  

After binary multivariate logistic regression analysis, the independent risk factors for PAH identified in this study were  identified as pericardial effusion (odds ratio [OR]=21.290, P< .001), anti-RNP antibody (OR=12.399, P<.001), baseline SLE duration (OR=1.118, P=.007), interstitial lung disease (OR=17.027, P<.001=, without acute rash (OR=3.258, P=.019), anti-SSA antibody (OR=4.836, P=.004), SLE Disease Activity Index (SLEDAI) ≤9 (OR = 26.426, P<.001), erythrocyte sedimentation rate (ESR)≤20 mm/h (OR=12.068, P<.001), and uric acid > 357 μmol/L (OR=9.666, P<.001).  

These findings were in agreement with findings in a prior study that anti-RNP antibodies were independent risk factors for PAH.¹

Summary and Clinical Applicability

This study identified the following variables that were associated with PAH in a group of SLE patients: 

• Pericardial effusion
• Anti-RNP antibody
• SLE duration
• Interstitial lung disease
• Absence of acute rash
• Anti-SSA antibody
• SLEDAI≤9
• ESR≤20 mm/h
• uric acid>357 μmol/L

This study was limited by its case control design, which by definition made data collection retrospective. Additionally the population studied was limited to a single center, limiting generalizability. 

Reference

1. Lian F, Chen D, Wang Y, et al. Clinical features and independent predictors of pulmonary arterial hypertension in systemic lupus erythematosus. Rheumatol Int. 2012;32:1727–1731.

2. Huang C, Li M, Liu Y, et al. Baseline Characteristics and Risk Factors of Pulmonary Arterial Hypertension in Systemic Lupus Erythematosus Patients. Medicine (Baltimore). 2016;95(10):e2761.