Factors associated with incident severe pulmonary arterial hypertension in systemic autoimmune rheumatic diseases: a nationwide study.

OBJECTIVE: To assess the association of severe pulmonary arterial hypertension (PAH) with particulate matter <2.5 µm (p.m.2.5) 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 p.m.2.5. 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 ciclosporin (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.