Characteristics and Outcomes of Idiopathic Inflammatory Myositis Associated Interstitial Lung Disease in Rural Appalachia

SESSION TITLE: Diffuse Lung Disease: There Is More to This Than Meets the Eye SESSION TYPE: Rapid Fire Original Inv PRESENTED ON: 10/09/2023 12:00 pm - 12:45 pm PURPOSE: Interstitial lung disease (ILD) is a frequent manifestation and major cause of morbidity and mortality for patients with idiopathic interstitial myositis (IIM). Up to 30% of the patients with IIM have ILD. The clinical and radiographic manifestations of IIM-ILD are heterogeneous. The objective of our study was to characterize the patterns of IIM-ILD and determine the treatment outcomes of these patients in the rural Appalachian population of West Virginia. METHODS: A retrospective observational cross-sectional study was conducted between January 1, 2012 to August 31, 2022 at an academic medical center located in the WV rural Appalachia. 115 patients with IIM were identified through electronic medical record. Only 29 patients who had coexisting ILD based on radiographic findings and evaluation by a pulmonologist were included for the final analyses. RESULTS: Most patients were female (n=22, 76%), never-smokers (n=19, 65%), and had a mean age of 60.17 ± 12.92 years. Dyspnea (n=24, 83%) was the most common symptom with mean modified Medical Research Council (mMRC) scale of 2 ± 1.2. The mean duration of symptoms at first encounter was 4.57 ± 6.66 years. The most common IIM phenotype were dermatomyositis (n=15, 52%) and polymyositis (n=8, 27.6%). In patients with available serology testing (n=20), anti-Jo1 was present in the 55% (n=11). Radiographic patterns at presentation (n=27) were indeterminate for usual interstitial pneumonia (UIP) (n=12, 44%), non-specific interstitial pneumonia (NSIP) (n=5, 18%), and UIP (n=3, 11%). Treatment modalities included prednisone (n=20, 69%), azathioprine (n=14, 48%), mycophenolate mofetil (n=13, 45%), and nintedanib (n=2, 7%). Data for mMRC scale, computed tomography (CT), and pulmonary function testing (PFT) before and after treatment was available for 19, 17 and 18 patients respectively. After treatment, mMRC score improved or remained stable in 89% (n=17). Similarly, CT findings and PFT improved or remained stable in 59% (n=10) and 67% (n=12) of the patients. Mortality rate during the study period was 21% (n=6). CONCLUSIONS: Dermatomyositis and anti-Jo1 antibody were the most common phenotype and autoantibody associated with ILD. Similar findings were reported in larger retrospective cohort studies. The most common radiographic pattern in our cohort was indeterminate for UIP in contrast to other cohorts with NSIP being the predominant CT finding. While comparing the progression of ILD with other studies based on symptoms, radiographic findings and PFT, proportion of patients with stable and improved ILD was higher in our study. Despite improvement in the pulmonary disease with treatment, mortality rate was remarkably higher in this cohort compared to other ILD centers. Multiple extra-pulmonary factors have been associated with poor prognosis in IIM-ILD, as such, the increased mortality in our cohort may be due to non-pulmonary causes. CLINICAL IMPLICATIONS: Disease characteristics of IIM-ILD are quite similar in our study of patients in the rural Appalachian population compared to other IIM-ILD cohorts, however, non-pulmonary factors may have contributed to increased mortality. Further prospective cohort studies to evaluate predictors of mortality in IIM-ILD in this region are required. DISCLOSURES: No relevant relationships by Bathmapriya Balakrishnan No relevant relationships by Bhanusowmya Buragamadagu No relevant relationships by Vishal Deepak No relevant relationships by Sayanika Kaur No relevant relationships by Ty Landis No relevant relationships by FNU Rida Ul Jannat No relevant relationships by Rachel Salyer