A patulous esophagus on high-resolution computed tomography (HRCT) of the thorax is frequently observed in patients with systemic sclerosis (SSc). Microaspiration has been purported to play a role in the development and progression of SSc interstitial lung disease (ILD), but studies examining the role of microaspiration in SSc ILD have yielded conflicting results. This study was conducted to determine the association between esophageal diameter and SSc ILD.
A cross-sectional study of Northwestern Scleroderma Registry patients with available HRCT exams was conducted. The predictor variable was the widest esophageal diameter (WED) on HRCT, and the primary and secondary outcome variables were radiographic ILD and pulmonary function tests respectively. The degree of radiographic ILD was assessed using a semi-quantitative score adapted from published methods. Estimated regression coefficients adjusted for age, sex, race, body mass index, smoking; SSc disease subtype, serum autoantibodies, and disease duration; modified Rodnan skin score, proton pump inhibitor, and immune suppressant medication use and erythrocyte sedimentation rate were calculated.
A total of 270 subjects were studied. In the adjusted analyses, there were positive associations between WED and total ILD score (β = 0.27; 95% CI: 0.09-0.41), fibrosis (β = 0.15; 95% CI: 0.07-0.23), and ground glass opacities (β = 0.12; 95% CI: 0.04-0.20); there were negative associations between WED and FVC % predicted (β = -0.42; 95% CI: -0.69 to -0.13), and adjusted DLCO % predicted (β = -0.45; 95% CI: -0.80 to -0.09) after adjusting for potential confounders.
Increasing esophageal diameter on HRCT in patients with SSc is associated with more severe radiographic ILD, lower lung volumes, and lower DLCO % predicted. Longitudinal studies are needed to determine if esophageal dilatation is associated with the incidence and/or progression of ILD in patients with SSc.