Predictors of pulmonary-functional decline in systemic sclerosis: A university hospital experience

Introduction: Pulmonary disease is the leading cause of morbidity and mortality in systemic sclerosis (SSc) patients; however, prognostication remains challenging. There is lack of consensus about the diagnostic accuracy of functional and anatomic tests Objective: Determinate the diagnostic performance, individually and combined, of anatomic and functional testing for pulmonary functional decline. Methods: We conducted a retrospective observational cohort study. All adults patients with diagnosis of SSc according to ACR/EULAR criteria during 2007 and 2018 were analyzed. Of the total of 201 patients, 95 offered complete record of clinical features, high resolution computed tomography (HRCT) at baseline and Pulmonary function test (PFT). PFT included: FVC, TLC and DLCO. Progression was defined as a ≥ 10% decrease in FVC at 2 year-control. Results: Among the 95 patients: 87 (91,6%) were women, mean age was 57 +/- 12 years. 53 (55,8%) showed interstitial lung disease (ILD) on HRCT and 26 (27,4%) had functional progression. Regarding the PFT of progressors and non-progressors groups: TLC (%of predicted) 86,5 vs 91,5 (p=0,006); DLCO (%of predicted) 70,0 vs 81,0 (p=0,035). In multivariated analysis HRCT was independently related to functional progression (p= 0,040). Negative predicted value for HRCT was 90,24%. In order to combine the diagnosis value of both test (HRCT and PFT) we applied Net reclassification index (NRI): NRI=+0,07 for TLC in all scenarios and NRI=+0,22 in case of pathologic HRCT. Conclusions: Combination of HRCT and a complete PFT at baseline can help predict functional decline. HRCT may be preferred as first line screening tool whereas TLC can outperform the risk event prediction.