Table A5.
Mixed effects hierarchical multivariable logistic regression for in-hospital mortality adjusted for sex, illness severity, COVID-19 status, frailty, ICU activity index and hospital type (with site as random effect) in all patients and in subgroups categorised by a. invasive therapies (invasive ventilation, renal replacement or ECMO), b. no invasive therapies and c. patients in public hospital ICUs.
| Whole study cohort |
Subgroups |
|||||||
|---|---|---|---|---|---|---|---|---|
| All patients |
a. Invasive ventilation, renal replacement, ECMO |
b. No invasive ventilation, renal replacement, ECMO |
c. Public Hospital ICUs |
|||||
| OR (95% CI) | p value | OR (95% CI) | p value | OR (95% CI) | p value | OR (95% CI) | p value | |
| CCRN >75% | Reference value | Reference value | Reference value | Reference value | ||||
| CCRN 50–75% | 1.21 (1.02–1.45) | 0.032 | 1.35 (1.11–1.64) | 0.003 | 1.05 (0.79–1.39) | 0.76 | 1.27 (1.06–1.52) | 0.011 |
| CCRN <50% | 1.21 (0.94–1.55) | 0.14 | 1.28 (0.98–1.66) | 0.07 | 1.14 (0.76–1.71) | 0.52 | 1.24 (0.97–1.59) | 0.08 |
| Male | 1.29 (1.13–1.46) | <0.001 | 1.07 (.91–1.26) | 0.41 | 1.51 (1.22–1.87) | <0.001 | 1.28 (1.12–1.47) | <0.001 |
| Australian & New Zealand Risk of Death (%) | 1.06 (1.06–1.07) | <0.001 | 1.06 (1.05–1.06) | <0.001 | 1.07 (1.07–1.08) | <0.001 | 1.06 (1.06–1.06) | <0.001 |
| COVID-19 patient | 2.61 (2.11–3.21) | <0.001 | 2.92 (2.21–3.86) | <0.001 | 2.48 (1.77–3.46) | <0.001 | 2.59 (2.10–3.20) | <0.001 |
| Frailty category (clinical frailty scale – CFS) | ||||||||
| Not frail (CFS <5) | Reference value | Reference value | Reference value | Reference value | ||||
| Pre-frail (CFS 5 or 6) | 1.67 (1.44–1.94) | <0.001 | 1.54 (1.29–1.85) | <0.001 | 2.62 (1.96–3.49) | <0.001 | 1.62 (1.40–1.89) | <0.001 |
| Frail (CFS >6) | 2.89 (2.34–3.57) | <0.001 | 1.99 (1.44–2.75) | <0.001 | 6.10 (4.39–8.48) | <0.001 | 2.60 (2.10–3.23) | <0.001 |
| Frailty score missing | 1.49 (1.08–2.03) | 0.014 | 0.86 (0.64–1.14) | 0.29 | 3.18 (1.98–5.11) | <0.001 | 1.09 (0.77–1.55) | 0.62 |
| ICU activity index | 1.03 (0.86–1.24) | 0.72 | 0.95 (0.76–1.19) | 0.65 | 1.01 (0.76–1.34) | 0.96 | 1.01 (0.84–1.22) | 0.91 |
| Hospital classification | ||||||||
| Tertiary (5 ICUs) | Reference value | Reference value | Reference value | Reference value | ||||
| Metropolitan (6 ICUs) | 1.09 (0.83–1.44) | 0.54 | 1.06 (0.85–1.33) | 0.59 | 1.38 (0.90–2.12) | 0.14 | 1.02 (0.80–1.29) | 0.89 |
| Rural/regional (4 ICUs) | 1.03 (0.71–1.49) | 0.89 | 1.18 (0.81–1.73) | 0.39 | 1.25 (0.72–2.17) | 0.43 | 0.94 (0.67–1.32) | 0.73 |
| Private (5 ICUs) | 0.94 (0.64–1.38) | 0.75 | 1.16 (0.76–1.76) | 0.48 | 1.04 (0.60–1.82) | 0.88 | Not applicable | |
| AUROC | 0.892 | 0.878 | 0.892 | 0.886 | ||||
| Brier score | 0.063 | 0.093 | 0.040 | 0.070 | ||||
Each column represents a separate multivariable hierarchical logistic regression model. The Australian and New Zealand Risk of Death (ANZROD) model includes age, acute physiological and biochemical disturbance, chronic comorbidities, treatment limitations, elective surgical status and source of admission with individual predictive equations for each ICU admission diagnosis. Sex, frailty and COVID-19 status were entered separately into each model because these are not included in ANZROD.
AUROC, Area under receiver operating characteristic curve; CCRN, Critical Care Registered Nurse; ECMO, Extra-corporeal Membrane Oxygenation, ICU, Intensive Care Unit: OR (95% CI), Adjusted odds ratio and 95% confidence interval.