Clinical profile of patients with systemic autoimmune diseases treated in the intensive care unit who developed diffuse alveolar haemorrhage - an observational retrospective cohort study

Background: Patients with autoimmune diseases constitute a relatively low percentage of the intensive care unit (ICU) population but their prognosis is particularly poor, partially due to involvement of multiple organs as well as complications related to immunosuppressive treatment. Diffuse alveolar haemorrhage (DAH) is one of the most life-threatening presentations of autoimmune diseases, associated with worse outcomes. The aim of this study is to report about clinical factors associated with DAH in the ICU setting and to assess the survival in 5-year follow-up. Methods: This is an observational, retrospective, cohort study performed in the ICU of the University Hospital in Krakow, Poland. We enrolled 21 patients treated for the first time in the ICU due to autoimmune diseases, who developed DAH. Severity of patients' clinical condition was assessed on the first day using APACHE II, APACHE III, SAPS II and SOFA scores. Mortality was assessed during the ICU stay and in 5-year follow-up. Results: The median age of the study population was 53 (18-78) years and 13 (61.9%) of patients were females. The most common diagnoses were granulomatosis with polyangiitis (38.1%), systemic lupus erythematosus (23.8%) and microscopic polyangiitis (14.3%). Most of the patients required mechanical ventilation (85.7%), renal replacement therapy (57.1%) and blood product transfusions (71.4%). Mortality in the ICU was 52.4%, while in both 1-year and 5-year follow-up it was 76.2%. Conclusion: Patients who develop DAH in the course of autoimmune diseases and are treated in the ICU have a poor prognosis and often require advanced therapeutic measures.