C57-03 Covid-19 Hospitalization Outcomes in Connective Tissue Disease-associated With Interstitial Lung Disease: A Nationwide Analysis

Abstract Rationale Coronavirus disease 2019 (COVID-19) has caused significant morbidity and mortality worldwide. Patients with connective tissue diseases (CTDs) associated with interstitial lung disease (ILD) represent a particularly vulnerable population, with baseline mortality rates ranging from 20% in rheumatoid arthritis-associated ILD to 40% in systemic sclerosis. However, data describing COVID-19 hospitalization outcomes in this high-risk population remain limited. Methods This retrospective cohort study analyzed the Healthcare Cost and Utilization Project Nationwide Inpatient Sample (NIS) 2020 database, examining COVID-19 hospitalizations across US acute care facilities. Adult patients (≥18 years) with primary COVID-19 diagnosis were identified. Pre-existing ILD cases were excluded to isolate CTD-associated pulmonary involvement. We performed multivariable logistic regression to evaluate mortality and morbidity outcomes across specific CTDs: rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), systemic sclerosis (SSc), dermatomyositis/polymyositis (DPM), and Sjögren’s syndrome (SS). A comparison group included patients with non-ILD-associated autoimmune conditions to control immunosuppression effects. Results Among the 29,938 CTD patients analyzed (mean age 66.5 years, 75.7% female), the cohort comprised RA (n = 21,555, 72.0%), SLE (n = 5,725, 19.1%), SSc (n = 524, 1.8%), DPM (n = 354, 1.2%), and SS (n = 1,780, 5.9%). After multivariable adjustment, patients with CTDs had significantly increased all-cause in-hospital mortality compared to COVID-19 patients without CTDs (adjusted odds ratio aOR 1.20, 95% CI 1.10-1.31, P 0.001). Patients with DPM demonstrated the highest crude all-cause in-hospital mortality rate among all CTD categories. However, after multivariable adjustment, no individual CTD category had significantly different odds of in-hospital mortality compared to other CTD patients combined. Compared to patients with autoimmune diseases not associated with ILD, CTD patients had significantly higher in-hospital mortality (aOR 1.18, 95% CI 1.02-1.42, P = 0.049). Additionally, COVID-19 patients with CTDs had significantly increased odds of requiring invasive mechanical ventilation (aOR 1.18, 95% CI 1.08-1.29, P 0.001) and mortality associated with invasive mechanical ventilation (aOR 1.43, 95% CI 1.25-1.64, P 0.001) compared to COVID-19 patients without CTDs. Mean hospital length of stay and cost of hospitalization showed no significant differences between groups. Conclusion Patients hospitalized with COVID-19 infection who had CTDs associated with ILD demonstrated significantly increased risk of all-cause in-hospital mortality (20% higher), need for invasive mechanical ventilation (18% higher), and mortality associated with mechanical ventilation (43% higher) compared to patients without CTDs. These findings suggest unrecognized subclinical ILD prevalence in CTD populations. Enhanced pulmonary screening protocols and aggressive monitoring for CTD patients warrant implementation, particularly during respiratory viral epidemics to improve clinical outcomes in this vulnerable population. This abstract is funded by: None