Background/Purpose: Interstitial lung disease (ILD) is the leading cause of death in systemic sclerosis (SSc). Esophageal dysfunction and aspiration may play a role in SSc-ILD. We showed that esophageal dilation on high-resolution computed tomography (HRCT) scans correlated positively with radiographic ILD and negatively with forced vital capacity (FVC)¹. We also showed that a widest esophageal diameter (WED) >=19mm on HRCT had the highest combined sensitivity and specificity for associated ILD². The purpose of this retrospective, longitudinal study was to determine if a larger WED is a risk factor for SSc-ILD incidence and progression.

Methods: Subjects that fulfilled American College of Rheumatology 2013 SSc criteria with >= one HRCT and two pulmonary function tests were included. The first available HRCT was defined as the baseline exam. WED was measured. ILD was quantified by published methods³. In subjects without radiographic ILD and with baseline FVC >=70% predicted, incident restrictive lung disease was defined as new FVC <70% predicted. Change in FVC % predicted was used as a surrogate for ILD progression.

Results: In total, 249 subjects were included with a median follow up of 2.9 years (0.02-13.4y). Twenty-five subjects died. At baseline, 88 (82%) with a WED >=19mm had radiographic ILD compared with 94 (66%) with a WED <19mm (p=0.005; Table 1). Three of 55 without baseline ILD developed incident restrictive lung disease. At baseline, those with WED >=19mm had an 8.38 lower FVC % predicted than those with WED<19mm. In total, there was no clinically significant decline (i.e. >5% change) in FVC % predicted (Fig. 1). There was no significant difference in change in FVC % predicted between those with WED >=19 vs. <19mm (beta=0.2663; 95% CI -0.2256, 0.7583).

Conclusion: SSc-ILD often occurs before referral to a tertiary center. Those with a larger WED had an FVC % predicted at baseline that was clinically and statistically significantly lower than those with a smaller WED. Despite this, a larger WED at baseline was not associated with more rapid decline in FVC % predicted. References:   1. Richardson et al. Esophageal dilatation and interstitial lung disease in systemic sclerosis: a cross-sectional study. Semin Arthritis Rheum 2016   2. Hoffmann et al. Comment on: Esophageal dilatation and interstitial lung disease in systemic sclerosis: a cross-sectional study. Semin Arthritis Rheum 2016   3. Kazerooni et al. Thin-section CT obtained at 10-mm increments versus limited three-level thin-section CT for idiopathic pulmonary fibrosis: correlation with pathologic scoring. AJR Am J Roentgenol 1997;169:977-83