Cardiopulmonary exercise testing and prognosis in patients with systemic sclerosis without baseline pulmonary hypertension: a prospective cohort study.

Cardiopulmonary Exercise Testing (CPET) is a standardized, non-invasive procedure assessing pulmonary, cardiovascular, hematopoietic, and skeletal muscle functions during a symptom-limited test. Few studies have examined whether CPET is of prognostic value in Systemic Sclerosis (SSc), a disease characterized by highly increased cardiorespiratory morbidity and mortality. To examine the prognostic value of CPET in SSc patients without baseline pulmonary hypertension (PH). Sixty-two consecutive SSc patients underwent CPET, Pulmonary Function Tests (PFTs) and echocardiography at baseline. Four patients with Right Ventricular Systolic Pressure ≥ 40 mmHg, were excluded. Participants repeated PFTs approximately every 3 years. At the end of the follow-up period [median (IQR): 9.79 (2.78) years] patient vital status was recorded. Cox Regression analysis was used to identify predictors of deterioration of PFTs and 10-year survival. Median (IQR) age of 58 patients (90% women) at baseline was 54.0 (15.0) years, whereas 10-year survival was 88%. Baseline respiratory Oxygen uptake (VO2max) predicted PFT deterioration, defined either as a decline in FVC ≥ 10% or a combined decline in FVC 5%-9% plus DLCO ≥ 15%, during follow-up, after correction for age, gender and smoking status (HR: 0.874, 95%CI: 0.779-0.979, p = 0.021). In addition, lower baseline VO2max (HR = 0.861, 95%CI:0.739-1.003, p = 0.054) and DLCO (HR = 0.957, 95%CI: 0.910-1.006 p = 0.088), as well as male gender (HR = 5.68, 95%CI: 1.090-29.610 p = 0.039) and older age (HR = 1.069, 95%CI: 0.990-1.154, p = 0.086) were associated, after adjustment, with an increased risk for death. In the absence of baseline PH, CPET indices may predict pulmonary function deterioration and death in SSc patients during a nearly 10-year follow-up period.