LAUSR

BACKGROUND Inhalational exposures are increasingly recognized as contributing factors in interstitial lung disease (ILD). However, the characteristics of both exposures and exposed patients are not well understood. We hypothesized that domestic and occupational inhalational exposures would be common and associated with differences in demographics, clinical characteristics, and transplant-free survival in patients with all forms of ILD. RESEARCH QUESTION What is the prevalence of inhalational exposures across all ILD diagnoses, and are these exposures associated with differences in demographics, clinical characteristics, and transplant-free survival? STUDY DESIGN AND METHODS Patients from a tertiary ILD clinic underwent an interview designed to capture inhalational exposures including occupational, home, hobbies, and tobacco. Demographic and survival data were collected from the electronic medical record. Survival analysis was performed using Cox regression to compare exposed versus unexposed patients and adjusted for gender, age, physiology (GAP) score and smoking. RESULTS One hundred fifty-six patients seen between May and October 2018 were analyzed. Patients had a wide variety of multidisciplinary diagnoses (MDD), with a minority (14%) of patients with hypersensitivity pneumonitis (HP). One hundred and one (65%) patients had potentially relevant inhalational exposures. More men than women had a history of any exposure (82% versus 51%, p<0.001), occupational exposure (66% versus 14%, p<0.001) and multiple exposures (56% versus 26%, p<0.001). White race was associated with bird and hobby exposure. Patients with any exposure had worse transplant-free survival (unadjusted HR=2.58, 95%CI=1.13-5.92, P=0.025), but this was not statistically significant after adjustment (HR=1.82, 95%CI=0.77-4.27, P=0.17). INTERPRETATION A standardized interview revealed a majority of patients across all types of ILD had potentially relevant inhalational exposures. Exposures were markedly different based on demographics and were associated with worse transplant-free survival, but this survival difference was not significant after multivariable adjustment. Identification and avoidance of exposures represent actionable targets in ILD management.