Survival and prognostic factors in systemic sclerosis-associated pulmonary hypertension: a systematic review and meta-analysis

Objective: Pulmonary hypertension (PH) is a frequent and life-limiting complication of systemic sclerosis (SSc). However, data on survival rates and their evolution over time, as well as prognostic factors in SSc complicated by PH, are still conflicting. The aim of this study was to conduct a systematic review and meta-analysis of cohort studies to assess pooled survival and prognostic factors for survival in patients with SSc-associated PH.

Methods: For this systematic review and meta-analysis, we searched the Medline and EMBase databases (January 1960 to January 2012). All cohort studies in which survival and/or prognostic factors for SSc-associated PH were reported were included in the analysis. We calculated the pooled survival rates and analyzed their evolution over time and identified prognostic factors for survival.

Results: Twenty-two studies were included, representing a total of 2,244 patients with SSc-associated PH. The pooled 1-, 2-, and 3-year survival rates were 81% (95% confidence interval [95% CI] 79-84%), 64% (95% CI 59-69%), and 52% (95% CI 47-58%), respectively. Meta-regression did not reveal a significant change in survival over time, while baseline hemodynamic measures of PH severity were significantly correlated with survival. In patients with SSc complicated by pulmonary arterial hypertension (PAH), age, male sex, diffusing capacity for carbon monoxide (DLCO), pericardial effusion, and the parameters classically associated with the severity of idiopathic PAH, including the 6-minute walk distance, mean pulmonary artery pressure, cardiac index, and right atrial pressure, were significant prognostic factors. DLCO and pericardial effusion were the only prognostic factors in patients with interstitial lung disease-related PH.

Conclusion: Our meta-analysis revealed a poor pooled 3-year survival rate of 52% in patients with SSc-associated PH. Baseline hemodynamic measures of PAH severity, but not the period of time during which patients were included in the studies, correlated significantly with survival in patients with SSc-associated PAH. All of the prognostic factors typically observed in idiopathic PAH, including the 6-minute walk distance and right atrial pressure, were also prognostic factors in SSc-associated PAH.