Factors Associated with Incident Severe Pulmonary Arterial Hypertension in Systemic Autoimmune Rheumatic Diseases: a Nationwide Study

Objectives To assess the association of severe pulmonary arterial hypertension (PAH) with particulate matter <2.5 μm (PM2.5) and clinical data in patients with systemic autoimmune rheumatic diseases (SARDs). Methods We used the 2003–2017 nationwide data in Taiwan to identify patients with SARDs, including systemic lupus erythematosus, rheumatoid arthritis, systemic sclerosis, dermatomyositis/polymyositis and primary Sjögren’s syndrome. We identified 479 cases with severe PAH and selected controls matched (1:4) for age, sex, and index-year. We used conditional logistic regression analysis to determine factors associated with risks for severe PAH shown as odds ratios (ORs) with 95% confidence intervals (CIs). Results We found that severe PAH was highly associated with interstitial lung disease (OR, 8.57; 95% CI, 5.52–13.32), congestive heart failure (OR, 7.62; 95% CI, 5.02–11.55), valvular heart disease (OR, 3.34; 95% CI, 2.03–5.50) and slightly associated with thyroid diseases (OR, 1.88; 95% CI, 1.18–3.00), but not the level of exposure to PM2.5. Increased risk for PAH was found in patients receiving corticosteroid (prednisolone equivalent dosage, mg/day, OR, 1.03; 95% CI, 1.01–1.05), biologics (OR, 2.18; 95% CI, 1.15–4.12) as well as immunosuppressants, including cyclosporin (OR, 2.17; 95% CI, 1.31–3.59), azathioprine (OR, 1.96; 95% CI, 1.48–2.61), cyclophosphamide (OR, 2.01; 95% CI, 1.30–3.11) and mycophenolate mofetil/mycophenolic acid (OR, 2.42; 95% CI, 1.37–4.27), and those with the highest level of insured amount (reference, lowest level; OR, 0.53; 95% CI, 0.34–0.83). Conclusion The population-based study identified risks for severe PAH in patients with SARDs, and these findings provide evidence for PAH risk stratification in patients with SARDs.