Abstract
Data about pulmonary arterial hypertension (PAH) patients living in low- and middle-income countries remain scarce. This study assessed prognostic factors associated with time to clinical worsening (CW) or death of a cohort of PAH patients in Minas Gerais, Brazil. This retrospective cohort study describes baseline clinical variables by PAH etiology and estimates time from diagnosis to CW [all-cause death, any-cause hospitalization, or disease progression (decrease of ≥ 15% in 6MWD and need for additional PAH therapy or worsening of functional class (FC)] and time to death. 79 out of 102 participants developed CW and 38 died while under follow-up. The most prevalent etiologies were PAH associated with schistosomiasis (PAH-Sch), idiopathic (IPAH), with congenital heart disease (PAH-CHD), and with connective tissue disease (PAH-CTD). The overall median event-free time to CW was 3.3 (95% CI, 2.3-4.6) years, which was similar across etiologies (log-rank test: p = 0.12). WHO FC III-IV, DLCO < 70%, heart rate recovery in 1 min after the 6-min walk test (HRR1) < 18 beats/minute, and baseline mPAP ≥ 50 mmHg were predictive of CW-free time. The median time to all-cause mortality was 10.2 (95% CI, 6.8 - > 10) years and varied among etiologies (log-rank test: p < 0.001). Time to CW was statistically independent of PAH etiology but depended on baseline WHO FC, DLCO, HRR, and mPAP. After CW events, PAH-Sch and PAH-CTD survived less on average than IPAH and PAH-CHD participants.