Annual prevalence, characteristics, and outcomes of intensive care patients with skin or soft tissue infections in Australia and New Zealand: A retrospective cohort study between 2006-2017.

Background: There are limited published data on the epidemiology of skin and soft tissue infections (SSTIs) requiring intensive care unit (ICU) admission. This study intended to describe the annual prevalence, characteristics, and outcomes of critically ill adult patients admitted to the ICU for an SSTI.

Methods: This was a registry-based retrospective cohort study, using data submitted to the Australian and New Zealand Intensive Care Society Adult Patient Database for all admissions with SSTI between 2006 and 2017. The inclusion criteria were as follows: primary diagnosis of SSTI and age ≥16 years. The exclusion criteria were as follows: ICU readmissions (during the same hospital admission) and transfers from ICUs from other hospitals. The primary outcome was in-hospital mortality, and the secondary outcomes were ICU mortality and length of stay (LOS) in the ICU and hospital with independent predictors of outcomes.

Results: Admissions due to SSTI accounted for 10 962 (0.7%) of 1 470 197 ICU admissions between 2006 and 2017. Comorbidities were present in 25.2% of the study sample. The in-hospital mortality was 9% (991/10 962), and SSTI necessitating ICU admission accounted for 0.07% of in-hospital mortality of all ICU admissions between 2006 and 2017. Annual prevalence of ICU admissions for SSTI increased from 0.4% to 0.9% during the study period, but in-hospital mortality decreased from 16.1% to 6.8%. The median ICU LOS was 2.1 days (interquartile range = 3.4), and the median hospital LOS was 12.1 days (interquartile range = 20.6). ICU LOS remained stable between 2006 and 2017 (2.0-2.1 days), whereas hospital LOS decreased from 15.7 to 11.2 days. Predictors for in-hospital mortality included Australian and New Zealand Risk of Death scores [odds ratio (OR): 1.07; confidence interval (CI) (1.05, 1.09); p < 0.001], any comorbidity except diabetes [OR: 2.00; CI (1.05, 3.79); p = 0.035], and admission through an emergency response call [OR: 2.07; CI (1.03, 4.16); p = 0.041].

Conclusions: SSTIs are uncommon as primary ICU admission diagnosis. Although the annual prevalence of ICU admissions for SSTI has increased, in-hospital mortality and hospital LOS have decreased over the last decade.