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.

Air pollutants and development of interstitial lung disease in patients with connective tissue disease: a population-based case-control study in Taiwan.

OBJECTIVE: The aim of this study was to assess the association between air pollutant exposure and interstitial lung disease (ILD) in patients with connective tissue diseases (CTDs). SETTING: A nationwide, population-based, matched case-control study in Taiwan. PARTICIPANTS: Using the 1997-2013 Taiwanese National Health Insurance Research Database, we identified patients with newly diagnosed CTD during 2001-2013, including systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), systemic sclerosis (SSc), dermatomyositis (DMtis)/polymyositis (PM) and primary Sjögren's syndrome (pSS). PRIMARY AND SECONDARY OUTCOME MEASURES: Patients with newly diagnosed ILD during 2012-2013 were identified as ILD cases, and selected patients with CTD without ILD matching (1:4) the CTD cases for CTD diagnosis, age, gender, disease duration and year of ILD diagnosis date were identified as non-ILD controls. Data of hourly level of air pollutants 1 year before the index date were obtained from the Taiwan Environmental Protection Agency. The association between ILD and air pollutant exposure was evaluated using logistic regression analysis shown as adjusted ORs (aORs) with 95% CIs after adjusting for potential confounders. RESULTS: We identified 505 newly diagnosed CTD-ILD patients, including 82 with SLE, 210 with RA, 47 with SSc, 44 with DMtis/PM and 122 with pSS. Ozone (O3) exposure (per 10 ppb) was associated with a decreased ILD risk in patients with CTD (aOR, 0.51; 95% CI, 0.33 to 0.79) after adjusting for potential confounders. CONCLUSIONS: A previously unrecognised inverse correlation was found between O3 exposure and ILD in patients with RA and SSc. Further studies are warranted to explore the underlying mechanisms.