Prognostic factors of mortality and 2-year survival analysis of systemic sclerosis with pulmonary arterial hypertension in Thailand

Abstract

Aims: Pulmonary arterial hypertension (PAH) is a major complication and cause of death in systemic sclerosis (SSc). Our objective was to identify the predictive factors of mortality and the 2-year survival rate among Thai sufferers of PAH-SSc.

Methods: An historical cohort study was performed among PAH-SSc patients followed up at Srinagarind Hospital, Thailand, between January 2005 and December 2008. Kaplan-Meier and Cox regression analyses were used to estimate the probability of survival and to assess the significant factors associated with death.

Results: Pulmonary arterial hypertension was recognized in 60 patients using ECHO criteria, right ventricular systolic pressure (RVSP) > 35 mmHg. Two-thirds of the patients were female, > 50 years of age, with the dSSc subtype. Twenty patients (33.3%) died: the mortality rate was 15.6% per 100 person-years. The respective 1-, 2-, 3- and 4-year survival rate was 86.1%, 71.3%, 64.6% and 53.9%. The majority (85%) died without any specific treatment for PAH. Using univariate analysis, the mortality risk was associated with: the WHO functional class (FC) III (HR = 27.82), visceral organ involvement (HR = 5.14), myositis (HR = 3.14), esophageal dysmotility (HR = 3.08) and pericarditis (HR = 2.84). Using Cox regression, the only predictor of death was FCIII. The causes of death in PAH-SSc were related to PAH (60%), infection (30%) and acute renal failure (10%).

Conclusion: Up to one-third of Thai sufferers of PAH-SSc died within 2 years of PAH diagnosis, without any specific treatment being given. Increased mortality risk was found in SSc patients who had FCIII and visceral organ involvement.