Indigenous Australians critically ill with sepsis: Characteristics, outcomes, and areas for improvement.

BACKGROUND: Aboriginal and Torres Strait Islander Australians have amongst the highest incidence of sepsis globally. OBJECTIVE: The objective of this study was to describe the characteristics, short- and long-term outcomes of non-Indigenous, Aboriginal Australian and Torres Strait Islander Australians admitted with sepsis to an intensive care unit (ICU) to inform healthcare outcome improvement. METHODS: A retrospective cohort study of 500 consecutive sepsis admissions to the Cairns Hospital ICU compared clinical characteristics, short-term (before ICU discharge) and long-term (2000 days posthospital discharge) outcomes. Cohort stratification was done by voluntary disclosure of Indigenous status. RESULTS: Of the 442 individual admissions, 145 (33%) identified as Indigenous Australian. Indigenous and non-Indigenous Australians had similar admission Acute Physiology and Chronic Health Evaluation-3 scores (median [interquartile range]: 70 [52-87] vs. 69 [53-87], P = 0.87), but Indigenous patients were younger (53 [43-60] vs. 62 [52-73] years, P < 0.001) and were more likely to have chronic comorbidities such as type 2 diabetes (58% vs. 23%, P < 0.001), cardiovascular disease (40% vs 28%, P = 0.01), and renal disease (39% vs. 10%, P < 0.001). They also had more hazardous healthcare behaviours such as smoking (61% vs. 45%, P = 0.002) and excess alcohol consumption (40% vs. 18%, P < 0.001). Despite this, the case-fatality rate of Indigenous and non-Indigenous Australians before ICU discharge (13% vs. 12%, P = 0.75) and 2000 days post hospital discharge (25 % vs. 28 %, P = 0.40) was similar. Crucially, however, Indigenous Australians died younger both in the ICU (median [interquartile range] 54 (50-60) vs. 70 [61-76], P < 0.0001) and 2000 days post hospital discharge (58 [53-63] vs. 70 [63-77] years, P < 0.0001). CONCLUSIONS: Although Indigenous Australians critically ill with sepsis have similar short and long-term mortality rates, they present to hospital, die in-hospital, and die post-discharge significantly younger. Unique cohort characteristics may explain these outcomes, and assist clinicians, researchers and policy-makers in targeting interventions to these characteristics to best reduce the burden of sepsis in this cohort and improve their healthcare outcomes.

The 4-Hour Cairns Sepsis Model: A novel approach to predicting sepsis mortality at intensive care unit admission.

BACKGROUND: Sepsis commonly causes intensive care unit (ICU) mortality, yet early identification of adults with sepsis at risk of dying in the ICU remains a challenge. OBJECTIVE: The aim of the study was to derive a mortality prediction model (MPM) to assist ICU clinicians and researchers as a clinical decision support tool for adults with sepsis within 4 h of ICU admission. METHODS: A cohort study was performed using 500 consecutive admissions between 2014 and 2018 to an Australian tertiary ICU, who were aged ≥18 years and had sepsis. A total of 106 independent variables were assessed against ICU episode-of-care mortality. Multivariable backward stepwise logistic regression derived an MPM, which was assessed on discrimination, calibration, fit, sensitivity, specificity, and predictive values and bootstrapped. RESULTS: The average cohort age was 58 years, the Acute Physiology and Chronic Health Evaluation III-j severity score was 72, and the case fatality rate was 12%. The 4-Hour Cairns Sepsis Model (CSM-4) consists of age, history of renal disease, number of vasopressors, Glasgow Coma Scale, lactate, bicarbonate, aspartate aminotransferase, lactate dehydrogenase, albumin, and magnesium with an area under the receiver operating characteristic curve of 0.90 (95% confidence interval = 0.84-0.95, p < 0.00001), a Nagelkerke R2 of 0.51, specificity of 0.94, a negative predictive value of 0.98, and almost identical odds ratios during bootstrapping. The CSM-4 outperformed existing MPMs tested on our data set. The CSM-4 also performed similar to existing MPMs in their derivation papers whilst using fewer, routinely collected, and inexpensive variables. CONCLUSIONS: The CSM-4 is a newly derived MPM for adults with sepsis at ICU admission. It displays excellent discrimination, calibration, fit, specificity, negative predictive value, and bootstrapping values whilst being easy to use and inexpensive. External validation is required.

The applicability of commonly used predictive scoring systems in Indigenous Australians with sepsis: An observational study.

BACKGROUND: Indigenous Australians suffer a disproportionate burden of sepsis, however, the performance of scoring systems that predict mortality in Indigenous patients with critical illness is incompletely defined. MATERIALS AND METHODS: The study was performed at an Australian tertiary-referral hospital between January 2014 and June 2017, and enrolled consecutive Indigenous and non-Indigenous adults admitted to ICU with sepsis. The ability of the ANZROD, APACHE-II, APACHE-III, SAPS-II, SOFA and qSOFA scores to predict death before ICU discharge in the two populations was compared. RESULTS: There were 442 individuals enrolled in the study, 145 (33%) identified as Indigenous. Indigenous patients were younger than non-Indigenous patients (median (interquartile range (IQR) 53 (43-60) versus 65 (52-73) years, p = 0.0001) and comorbidity was more common (118/145 (81%) versus 204/297 (69%), p = 0.005). Comorbidities that were more common in the Indigenous patients included diabetes mellitus (84/145 (58%) versus 67/297 (23%), p<0.0001), renal disease (56/145 (39%) versus 29/297 (10%), p<0.0001) and cardiovascular disease (58/145 (40%) versus 83/297 (28%), p = 0.01). The use of supportive care (including vasopressors, mechanical ventilation and renal replacement therapy) was similar in Indigenous and non-Indigenous patients, and the two populations had an overall case-fatality rate that was comparable (17/145 (12%) and 38/297 (13%) (p = 0.75)), although Indigenous patients died at a younger age (median (IQR): 54 (50-60) versus 70 (61-76) years, p = 0.0001). There was no significant difference in the ability of any the scores to predict mortality in the two populations. CONCLUSIONS: Although the crude case-fatality rates of Indigenous and non-Indigenous Australians admitted to ICU with sepsis is comparable, Indigenous patients die at a much younger age. Despite this, the ability of commonly used scoring systems to predict outcome in Indigenous Australians is similar to that of non-Indigenous Australians, supporting their use in ICUs with a significant Indigenous patient population and in clinical trials that enrol Indigenous Australians.