Survival in rheumatoid arthritis-associated pulmonary arterial hypertension compared with idiopathic pulmonary arterial hypertension.

BACKGROUND AND OBJECTIVE: In this study, we evaluated survival in rheumatoid arthritis-associated pulmonary arterial hypertension (RA-PAH) compared with idiopathic pulmonary arterial hypertension (IPAH) patients, and evaluate differences in disease severity and treatment. METHODS: We conducted a retrospective cohort study of RA-PAH and IPAH at the University Health Network Pulmonary Hypertension Programme, Toronto, Canada. The primary outcome was time to all-cause mortality. We evaluated survival using Kaplan-Meier curves. Using a propensity score-matched cohort, we used Cox proportional hazards models to estimate survival. RESULTS: Screening 1385 patients identified 18 RA-PAH and 155 IPAH patients. RA-PAH patients had an older median age of onset (64.0 vs 53.7 years) and lower baseline mean pulmonary arterial pressure (mPAP) (41 vs 50 mm Hg, P = 0.02). RA-PAH patients tended to have a higher proportion of females (83% vs 70%, relative risk 0.55, 95% confidence interval (CI): 0.19-1.57), lower proportion with baseline World Health Organization functional class III/IV (39% vs 52%), lower median baseline brain natriuretic peptide (58.4 vs 95.0 pg/mL) and longer baseline 6-min walk distance (440 vs 397 m). There were 35 deaths, 2/18 (11%) RA-PAH patients and 33/155 (21%) IPAH patients. The unadjusted 1-year survival was 93% for RA-PAH and 94% for IPAH. In the matched cohort, there were seven deaths: 2/18 (11%) RA-PAH and 5/18 (28%) IPAH patients, hazard ratio 1.53 (95% CI: 0.15-2.84). Separation of survival curves did not achieve statistical significance, log-rank 0.56. CONCLUSIONS: Compared with IPAH patients, RA-PAH patients have an older age of onset and lower baseline mPAP. RA-PAH patients have comparable survival to IPAH patients.