SAT0548 Prognostic factors for interstitial lung disease with microscopic polyangiitis

Background Many cases of interstitial lung disease (ILD) complicated by microscopic polyangiitis (MPA) show the UIP pattern on chest HRCT, being similar to idiopathic pulmonary fibrosis (IPF/UIP), and the associated prognosis is poor compared with that of MPA without ILD.1 However, the details have not been fully clarified. Objectives Prognostic factors of MPA-ILD sufficiently treated with immunosuppressive therapy were investigated. Methods Of consecutive patients with MPA who received inpatient treatment at our hospitals between 2001 and 2016, MPO-ANCA-positive patients who met the 2007 EMEA classification criteria and had concomitant ILD on HRCT were selected as the subjects. Using the clinical data and HRCT fibrosis score,2 the outcome and prognostic factors were retrospectively investigated. Results The subjects were 65 patients with MPA-ILD, 31 and 34 patients were male and female, respectively, and the median age (interquartile range) was 7367–76 years old. At the time of treatment initiation, MPO-ANCA was 129 (50.9–359) EU; KL-6, 461 (289–665) U/mL; Aa-DO2, 25.1 (15.6–34.2);%FVC, 81.2 (67.8–93.9)%; and%DLco/VA, 62.7 (45.3–73.2)%. On HRCT, the UIP and non-UIP patterns were observed in 44 and 21 patients, respectively. In treatment, prednisolone was administered to 63 patients, immunosuppressants were used in 55 patients, and blood purification therapy was concomitantly administered to 9 patients. MPO-ANCA on the final follow-up was lower than the detection sensitivity in 56 patients. The outcome was death in 23 patients, and the 5- and 10 year survival rates after treatment initiation were 69.8% and 51.1%, respectively (acute exacerbation of interstitial pneumonia: 5 patients, infection and alveolar haemorrhage: 3, infection: 1, pneumothorax: 1, lung cancer: 2, pulmonary hypertension: 1, sudden death: 4, heart failure: 2, renal failure: 2, cerebral haemorrhage: 1, intestinal haemorrhage: 1). Regarding lung disease-related death, the age (p=0.018),%FVC (p=0.026), HRCT fibrosis score (p Conclusions Many MPA-ILD patients showed the UIP pattern, but their prognosis was better than that of previously reported IPF/UIP patients, suggesting that early immunosuppressive therapy is effective. However, expansion of fibrosis was included in the factors indicating a poor prognosis, suggesting the limit of immunosuppressive therapy. References [1] Fernandez Casares M, Gonzalez A, et al. Microscopic polyangiitis associated with pulmonary fibrosis. Clin Rheumatol. 2015;34(7):1273–7. [2] Wells AU, Hansell DM, Rubens MB, et al. Fibrosing alveolitis in systemic sclerosis: indices of lung function in relation to extent of disease on computed tomography. Arthritis Rheum1997;40:1229–36. Disclosure of Interest None declared