Etiologies and Outcomes of Rheumatology Patients with Acute Respiratory Failure Requiring Intensive Care: A Single-Center Cohort Study of 259 Patients

Abstract Background: The etiologies of acute respiratory failure (ARF) in critically ill rheumatology patients remain unknown. We aimed to describe the clinical features, etiologies and outcomes of adult patients with systemic rheumatic diseases (SRDs) who were admitted to intensive care unit (ICU). Methods: We performed a retrospective study of all SRD patients with ARF who were admitted to a medical ICU between 2014 and 2018. We collected data on demographics, clinical characteristics, reasons for ICU admission and outcomes. Etiologies of ARF were classified as infection, SRD exacerbation, and undetermined. Independent predictors of ICU mortality were identified with multivariate logistic regression analysis. Results: A total of 259 patients admitted to ICU due to ARF were included in final analysis. Systemic lupus erythematosus, dermatomyositis/polymyositis (DM/PM), vasculitis and rheumatoid arthritis were the most common SRDs (78% of patients). Etiologies of ARF included infection (n = 209, 80.7%), SRD exacerbation (n = 71, 27.4%), and undetermined (n = 21, 8.1%). The most common pathogen was Pneumocystis jirovecii (39.8%), followed by Aspergillus spp. (33.2%), and cytomegalovirus (23.2%). One hundred and fifty-five patients (59.8%) died during ICU. Higher acute physiology and chronic health evaluation II score (odds ratio [OR] 1.118, 95% confidence interval [CI] 1.054 to 1.186, p < 0.001) and PaO2/FiO2 < 100 mmHg (OR 3.918, 95% CI 2.199 to 6.892, p < 0.001), DM/PM (OR 4.898, 95% CI 1.949 to 12.309, p = 0.001), vasculitis (OR 3.007, 95% CI 1.237 to 7.309, p = 0.015) and Pneumocystis pneumonia (OR 2.345, 95% CI 1.168 to 4.705, p = 0.016) were independent predictors of ICU mortality. Conclusions: Opportunistic infections and SRD exacerbation were the most common etiologies of ARF in patients with SRDs requiring ICU admission, with high ICU mortality. Development of a standard protocol for differential diagnosis in this group of immunocompromised patients might help initiate definitive therapy and improve clinical outcome. Keywords: Infection, Systemic rheumatic disease, Acute respiratory failure, Etiology