THU0680 Survival analysis of patients with connective tissue disease associated interstitial lung disease
Authors: T. Xu, X. ZHANG
Journal: Annals of the Rheumatic Diseases (2018)

Rheumatoimmunologic Department, Guangdong Academy of Medical Sciences, Guangdong General Hospital, Guangzhou, China <h3>Background</h3> Interstitial lung disease (ILD) is common in connective tissue diseases (CTDs) and can lead to significant shortened survival. Although the various CTDs associated with ILD are often considered as a whole because of their sharing the same autoimmune nature, there are substantial differences in the natural course in each specific CTD. Still, there is little research comparing the mortalities in different underlying CTDs and investigated the risk factors. <h3>Objectives</h3> We aimed to examine mortality in patients with ILD secondary to dermatomyositis and polymyositis(DM/PM), systemic sclerosis(SSc), rheumatoid arthritis(RA), primary Sjögren syndrome (pSS), and systemic lupus erythematosus(SLE), to test whether the survival was associated with ILD imaging subtypes, as well as to identify independent risk factors for CTD-ILDs. <h3>Methods</h3> We retrospectively reviewed the medical records of patients with newly diagnosed CTD-ILD. The high-resolution computed tomography of lung images was reviewed by two expert pulmonary radiologists. According to imaging manifestations, ILD was categorised into three subtypes,<sup>1</sup> i.e., usual interstitial pneumonitis(UIP), nonspecific interstitial pneumonia(NSIP) and indeterminate, respectively. The extensity of ILD lesions was also evaluated as grade 1, 2, 3. The primary outcome assessed was all-cause mortality. We examined survival after stratifying on each specific CTD, or lung-CT imaging subtypes, respectively. We used Cox proportional hazards model to identify independent predictors of survival. <h3>Results</h3> Three hundred and twenty-five patients were included with a median follow-up time of 54 months. Eighty-four(25.8%) had DM/PM, 73 (22.5%) had SSc, 63 (19.4%) had RA, 58 (17.8%) had pSS, 47 (14.5%) had SLE. Overall, 98 (30.2%) patients died. The survival rate of pSS-ILD(85.1%) and SLE-ILD(79.3%) were significantly higher than other CTD-ILDs [SSc-ILD(68.5%), RA-ILD(66.7%), PM/DM-ILD(58.6%), p=0.009]. However, after categorised into three different ILD imaging subtypes, it showed no statistical differences in survival rates (64.5%, 73.6%, 69.5% of the UIP group, NSIP group, indeterminate group, respectively, p=0.558). Multivariable analysis revealed that compared with DM/PM-ILD, the mortality rate was significantly lower in pSS-ILD(RR=0.321, p=0.001), RA-ILD(RR=0.466, p=0.016), SSc-ILD(RR=0.566, p=0.045), and SLE-ILD patients(RR=0.363, p=0.018), and old age(RR=1.028, p=0.002), long course of disease (RR=1.004, p=0.005), extended ILD lesions(RR=1.854, p=0.025) were independent predictors of mortality in all types of CTD-ILD. The present study shows DM/PM-ILD patients had the worst prognosis then pSS-ILD, RA-ILD, SSc-ILD, and SLE-ILD patients. Age, disease course, intensity of ILD lesions at baseline is also critical for the survival of CTD-ILD patients. <h3>Conclusions</h3> The present study shows DM/PM-ILD patients had the worst prognosis then pSS-ILD, RA-ILD, SSc-ILD, and SLE-ILD patients. Age, disease course, intensity of ILD lesions at baseline is also critical for the survival of CTD-ILD patients. <h3>Reference</h3> [1] Travis WD, Costabel U,et al. An official American Thoracic Society/European Respiratory Society statement: Update of the international multidisciplinary classification of the idiopathic interstitial pneumonias.Am J Respir Crit Care Med2013Sep 15;188(6):733–48. <h3>Acknowledgements</h3> We would like to thank Drs Zhenjun Zhao and Qian Liu for their review of the high-resolution computed tomography of lung images. <h3>Disclosure of Interest</h3> None declared