FRI0471 Prediction of progression of interstitial lung disease in patients with systemic sclerosis: the spar model
Authors: W. Wu, S. Jordan, M.O. Becker, R. Dobrota, B. Maurer, H. Fretheim, S. Ye, E. Siegert, Y. Allanore, A.M. Hoffmann-Vold, O. Distler
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Background</h3> The natural disease course of interstitial lung disease associated with systemic sclerosis (SSc-ILD) is highly heterogeneous. Currently, no data are available to distinguish a progressive disease course from a stable course when mild interstitial lung disease (ILD) is diagnosed in patients with systemic sclerosis (SSc). <h3>Objectives</h3> This study aimed to identify predictive clinical characteristics and establish a prediction model for the progression of mild ILD at 1 year follow-up in SSc patients. <h3>Methods</h3> Patients with SSc from two independent prospective cohorts were included in this observational study. All patients fulfilled the ACR/<sup>EULAR 2013</sup> criteria, had mild ILD at baseline diagnosed by HRCT (ILD extent &lt;20% lung involvement on HRCT), available baseline and follow-up pulmonary function tests, at least one annual follow-up visit, and no concomitant pulmonary hypertension or airflow obstruction. ILD progression was defined as a relative decrease in FVC%≥15%, or FVC%≥10% combined with DLCO%≥15% at 1 year follow-up. Candidate predictors for multivariate logistic regression were selected by expert opinion based on previous studies and clinical significance. Multiple imputation was used to address missing data. A prediction model for ILD progression was established in the derivation cohort and validated in the multinational validation cohort. <h3>Results</h3> A total of 25/98 and 25/117 SSc patients showed ILD progression in the derivation cohort and the validation cohort, respectively. Lower SpO<sub>2</sub> after six-minute walk test (6MWT) and arthritis ever were identified as independent predictors for ILD progression in the derivation, validation and pooled cohorts (figure 1). The optimal cut-off value for SpO<sub>2</sub> after 6MWT for ILD progression was determined as 94% by ROC curve analysis. In a simplified model, the presence of both <b>SP</b>O<sub>2</sub> after 6MWT≤94% and <b>AR</b>thritis ever were set to 1, giving a <b>SPAR</b> score ranging from 0 to 2. The derived SPAR model increased the prediction rate for ILD progression from 7.4% (scoring 0) to 91.7% (scoring 2) with an AUC [95% CI] of 0.83 [0.73 to 0.93] in the derivation cohort, and a similar AUC [95% CI] of 0.82 [0.70 to 0.94] in the validation cohort. <h3>Conclusions</h3> The evidence-based SPAR prediction model developed in our study might be helpful for the risk stratification of patients with mild SSc-ILD in clinical practice and cohort enrichment for future clinical trial design. <h3>References</h3> [1] Goh NS, Desai SR, Veeraraghavan S, et al. Interstitial lung disease in systemic sclerosis: a simple staging system. Am J Respir Crit Care Med2008;177(11):1248–54. [2] Swigris JJ, Zhou X, Wamboldt FS, et al. Exercise peripheral oxygen saturation (SpO<sub>2</sub>) accurately reflects arterial oxygen saturation (SaO<sub>2</sub>) and predicts mortality in systemic sclerosis. Thorax2009;64(7):626–30. [3] Avouac J, Walker UA, Hachulla E, et al. Joint and tendon involvement predict disease progression in systemic sclerosis: a EUSTAR prospective study. Ann Rheum Dis2016;75(1):103–9. <h3>Disclosure of Interest</h3> W. Wu: None declared, S. Jordan: None declared, M. O. Becker: None declared, R. Dobrota: None declared, B. Maurer Grant/research support from: AbbVie, Protagen, EMDO, Novartis, German SSc Society, Pfizer, Roche, Actelion, MSD, and OPO Foundation, H. Fretheim: None declared, S. Ye: None declared, E. Siegert: None declared, Y. Allanore Grant/research support from: BMS, Genentech-Roche, Inventiva, and Sanofi, Consultant for: Actelion, Bayer, Biogen, Boehringer, Genentech-Roche, Galapagos, Inventiva, Medac, Pfizer, Sanofi, and Servier, A. M. Hoffmann-Vold: None declared, O. Distler Grant/research support from: Actelion, Bayer, Boehringer Ingelheim, Mitsubishi Tanabe Pharma and Roche, Patent mir-29 for the treatment of systemic sclerosis licensed, Consultant for: Actelion, Bayer, BiogenIdec, Boehringer Ingelheim, ChemomAb, espeRare foundation, Genentech/Roche, GSK, Inventiva, Italfarmaco, Lilly, medac, MedImmune, Mitsubishi Tanabe Pharma, Pharmacyclics, Novartis, Pfizer, Sanofi, Sinoxa and UCB