Associated factors of early-onset pulmonary hypertension and clinical difference between early- and late-onset pulmonary hypertension in Thai systemic sclerosis.

Pulmonary hypertension (PH) is a major cause of death in systemic sclerosis (SSc). Detection of early-onset PH and its associated factors would be helpful for improving patient care. Our aims were to determine the factors associated with early-onset PH and to define the differences between early- and late-onset PH among SSc patients. A cohort study was conducted of 409 adult SSc patients who had followed-up between January 2014 and December 2016. Early-PH is defined when the onset of PH is diagnosed within 5 years of the disease. Logistic regression analysis was applied to determine the factors associated with early-PH. In 3409 person-years, we diagnosed 50 cases with PH confirmation by right heart catheterization, of whom 26 were early-PH (incidence 0.7 per 100 person-years; 95%CI:0.5-1.1). Among SSc with early-PH, 69.2% had the diffuse cutaneous SSc subset and the most common PH classification was PH due to interstitial lung disease (18 cases;69.2%). According to a logistic regression analysis, early-PH was associated with a WHO functional class (WHO-FC) II and higher, cardiomegaly according to chest radiography, and tricuspid regurgitation jet maximum velocity (TRVmax)>2.8 m/s with the respective OR of 20.12 (95%CI:1.59-255.35), 7.42 (95%CI:1.35-40.88), and 8.20 (95%CI:1.17-57.64). To contrast, early-PH had a negative association with gastrointestinal involvement (OR 0.08; 95%CI:0.01-0.56). Early-PH is prevalent among SSc patients and the most common cause is interstitial lung disease. A poor WHO-FC, cardiomegaly, and a high TRVmax are associated with early-PH. Gastrointestinal involvement is a protective factor for early-PH in SSc.