Outcome of patients with autoimmune diseases in the intensive care unit: a mixed cluster analysis

Abstract

Objectives: The interest on autoimmune diseases (ADs) and their outcome at the intensive care unit (ICU) has increased due to the clinical challenge for diagnosis and management as well as for prognosis. The current work presents a-year experience on these topics in a tertiary hospital.

Methods: The mixed-cluster methodology based on multivariate descriptive methods such as principal component analysis and multiple correspondence analyses was performed to summarize sets of related variables with strong associations and common clinical context.

Results: Fifty adult patients with ADs with a mean age of 46.7±17.55 years were assessed. The two most common diagnoses were systemic lupus erythematosus and systemic sclerosis, registered in 45% and 20% of patients, respectively. The main causes of admission to ICU were infection and AD flare up, observed in 36% and 24%, respectively. Mortality during ICU stay was 24%. The length of hospital stay before ICU admission, shock, vasopressors, mechanical ventilation, abdominal sepsis, Glasgow score and plasmapheresis were all factors associated with mortality. Two new clinical clusters variables (NCVs) were defined: Time ICU and ICU Support Profile, which were associated with survivor and no survivor variables.

Conclusions: Identification of single factors and groups of factors from NCVs will allow implementation of early and aggressive therapies in patients with ADs at the ICU in order to avoid fatal outcomes.

Keywords: Arthritis; Autoimmune Diseases; Outcomes research; Systemic Lupus Erythematosus; Systemic Sclerosis.

Figure 1

New cluster variable Time ICU. Within this cluster, three groups are observed, namely G1, G2 and G3. G1 was characterised by a short total ICU stay and long hospital stay before ICU admission. G2 had an opposite trend of that found in G1, that is, long total ICU stay and short hospital stay before ICU admission. Finally, G3 was related with short hospital stays before ICU and during ICU. Total days in ICU refers to the length of stay at ICU regardless the number of re-entries; Days before ICU admission refers to the length of hospital stay before ICU admission. ICU, Intensive care unit.

Figure 2

‘ICU support profile’ cluster. From this new cluster variable, four groups where obtained (A): (1) ICU support-G1, associated with high presence of all the studied supports except non-invasive mechanical ventilation and some sporadic dialysis; (2) ICU support-G2, associated with high presence of all the studied supports except CPR and DLY; (3) ICU support-G3, related with patients for whom little if any support was needed, and (4) ICU support-G4, associated with those patients requiring DLY and transfusion together with very few outcomes in other supports. (B) Profile of each group with respect to the original variables used to build the groups. (C) Profile of each original variable in terms of groups’ composition. 1: presence of the variable, 0: absence of the variable. CPR, cardiopulmonary resuscitation; MV, mechanical ventilation; NIMV, non-invasive MV; VSS, vasopressor support; TRNS, blood transfusion; DLY, dialysis.