Survival and predictors of mortality in australian patients with connective tissue disease-associated pulmonary arterial hypertension.

Abstract

Background/Purpose: We sought to determine predictors of mortality in connective tissue disease-associated pulmonary arterial hypertension (CTD-PAH). Method(s): This was a retrospective cohort study of patients with CTD-PAH recruited from six tertiary hospitals. In addition to data prospectively collected as part of the Australian Scleroderma Cohort Study, physician records were reviewed. PAH was defined on right heart catheterization. All patients had systemic sclerosis (SSc) or another underlying CTD. Records were censored at 31/12/09. Survival was determined using Kaplan-Meier estimates. Univariate and multivariable predictors of survival were determined using log-rank / Wilcoxon tests, and proportional hazards regression modelling. Result(s): Amongst 117 patients (105 female) there were 32 deaths. Mean age at PAH diagnosis was 61.5 +/- 11.4 years. SSc was the most common underlying CTD, accounting for 104 patients (88.9%). Forty-eight patients (41.0%) had coexistent interstitial lung disease (ILD). At baseline, mean six-minute walk distance was 325 +/- 127 m and 88 patients (75.2%) were in WHO functional class III. Average duration of follow-up from PAH diagnosis was 2.6 +/- 1.8 years. Seventy patients (59.8%) received monotherapy, 12 (10.3%) sequential monotherapy and 34 (29.0%) combination pulmonary vasodilator therapy. Bosentan was the most commonly prescribed medication, used in 102 patients (87.2%). Sildenafil was the next most common, followed by inhaled iloprost and sitaxentan. One-, two- and three-year survival was 94%, 89% and 73%, respectively (see Figure 1). On univariate analysis, predictors of mortality were WHO functional class IV at baseline, male sex, ILD, right ventricular dysfunction, pericardial effusion, absence of warfarin therapy, absence of combination therapy and higher mean right atrial pressure (mRAP) at PAH diagnosis. On multiple regression analysis, WHO functional class IV at baseline, higher mRAP at PAH diagnosis, coexistent ILD and absence of warfarin therapy remained independent predictors of mortality (see Table 1). (Table Presented) Conclusion(s): Among patients in this study, three-year survival is 73%; this is better than that reported in several studies of CTD-PAH in the current treatment era. Predictors of survival include lower WHO functional class at baseline, lower mRAP at PAH diagnosis and warfarin therapy, suggesting that earlier diagnosis of PAH and treatment with warfarin in addition to advanced pulmonary vasodilator therapy may improve survival in these patients.