Association of Gastroesophageal Factors and Worsening of Forced Vital Capacity in Systemic Sclerosis

OBJECTIVE: Interstitial lung disease (ILD) is a common complication of systemic sclerosis (SSc) and causes death. Once lung fibrosis occurs, disease course may become stable or decline. Little is known about risks for progression. We studied SSc-gastroesophageal (GE) involvement in relation to worsening forced vital capacity (FVC) on pulmonary function tests (PFT) to investigate whether it was related to progression. Our objective was to determine whether GE reflux and dysphagia are associated with progressive moderate/severe ILD as measured by PFT over 3 years. METHODS: The Canadian Scleroderma Research Group is a multicenter SSc database that collects data annually. Using indicators of GE involvement and annual PFT, comparisons were made between no/mild ILD, stable moderate/severe ILD, and progressive moderate/severe ILD groups based on changes of FVC. Multivariate analyses determined associations between GE factors and ILD development and progression. RESULTS: There were 1043 patients with SSc (mean age 55.7 yrs, mean disease duration 10.8 yrs); one-quarter had pulmonary fibrosis on chest radiograph that was related to FVC percentage predicted (Spearman's rho -0.39; p < 0.01). Physician indicators such as esophageal dysmotility (p = 0.009) and postesophageal dilatation (p = 0.041), and patient indicators such as difficulty swallowing (p = 0.016) and waking up choking (p = 0.026) were associated with low FVC. In comparing progressive and stable moderate/severe FVC (< 70% predicted), early satiety (p = 0.018) and a combination term of postdilatation and choking (p = 0.042) increased risk of progression of ILD. Topoisomerase I was not associated with progression over followup. CONCLUSION: Symptoms of esophageal dysmotility were associated with worsening FVC in SSc, especially if both need for esophageal dilatation and choking were present.