Acute respiratory worsening in a prospective CTD-ILD cohort

<bold>Background:</bold> Acute respiratory worsening (ARW) is a feared complication in connective tissue disease associated interstitial lung disease (CTD-ILD) but little is known about its frequency or prognostic significance. <bold>Objective:</bold> Assess incidence and triggers for ARW in CTD-ILD and its impact on hospitalization and transplant free survival (TFS). <bold>Method:</bold> We followed 113 CTD-ILD patients prospectively for 12 months. ARW was defined as development of dyspnea with <1 month duration that could not be explained by non-respiratory causes. We evaluated ARW-associated variables and triggers using logistic regression, including respiratory tract infection, immunosuppressants, and gastroesophageal reflux (GERD). The impact of ARW on TFS was analyzed with Kaplan Meier estimates and Cox regression using ARW as time-dependent variable. <bold>Result:</bold> We identified 49 episodes of ARW in 33 (29 %) patients. RTI was a trigger for nearly all ARW (97%) and resulted in acute hospitalization in 18 out of the 33 pts (51%). GERD or immunosuppressants, with a possible exception for rituximab (OR 2.1 (0.9, 4.7), p=0.08), were not associated with ARW. ARW was significantly associated with impaired TFS (HR 4.9 (1.4, 16.8), p=0.01), with 1-year survival at 77% vs 98% without ARW, p=0.006. <bold>Conclusion:</bold> ARW is a frequent and severe complication in CTD-ILD. RTI lead to the majority of ARW emphazising the need for identifying these events early to enable timely intervention and improve outcome. <fig><object-id>erj;64/suppl_68/PA4266/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig>