Pulmonary survival study in 91 patients with systemic sclerosis

Abstract

In systemic sclerosis (SSc), major determinant of morbidity and mortality is pulmonary complication including pulmonary interstitial lung disease (ILD) and pulmonary arterial hypertension (PAH). In this study, the natural course of pulmonary involvement in SSc patients was investigated. This was a historical cohort study of SSc patients at a referral center for SSc in Iran between February 1998 and December 2007. Patients had a standardized initial evaluation, and interstitial pulmonary involvement was established by high-resolution CT scan (HRCT). Pulmonary hypertension was assessed by tricuspid gradient on echocardiography. Development of abnormal FVC or DLCO was considered as secondary outcome. Analysis of pulmonary survival was performed for primary and secondary outcomes. Ninety-one SSc patients were included in the study with the mean age of 44.1 (14.8). Among these, 65 (71.4%) patients were classified as limited subtype (lcSSc) and 84 (93.3%) were women. PAH was investigated in 8 (8.2%) patients, 1 (6.7%) in dcSSc and 7 (15.9%) in lcSSc subtype of disease. ILD had developed after a median of 107 (SE = 24.4) months after the first symptom of SSc, and 29 patients (31.9%) developed pulmonary fibrosis. Alveolitis and fibrosis had developed after a median of 129.0 (22.9) and 259.0 (74.2) months, respectively. There was a significant difference in Alveolitis-free pulmonary survival between two subgroups of the disease, which showed pulmonary alveolitis developed later in limited SSc (P = 0.03). The difference was not significant in two subtypes when Cox regression model was used to identify the effect of other prognostic factors on pulmonary survival in patients. In the present study, clinical manifestations of two subtypes of disease were divergent at first; however they became convergent in late stages, and this was the same as results in previous studies. Echocardiography for evaluation of pulmonary hypertension and pulmonary function tests for early detection of ILD and PAH is recommended for SSc patients to detect early stages of pulmonary involvement before significant vascular and fibrotic changes occur.