Table 4.

Cox Regression Analyses

Variable	Unadjusted HR	95% CI	p value	Adjusted HRb	95% CI	p value
a. Univariate and multivariate Cox regression analyses of AKI associated with mortality at 30 days
AKI (all stages)	2.67	2.14–3.34	0.0000		n/a
No AKI	Ref	Ref	Ref	Ref	Ref	Ref
AKI stage 1	2.24	1.71–2.94	0.0000	1.59	1.19–2.13	0.0018
AKI stage 2	4.36	3.00–6.34	0.0000	2.71	1.82–4.05	0.0000
AKI stage 3	2.79	2.11–3.70	0.0000	2.99	2.17–4.11	0.0000
b. Univariate and multivariate Cox regression analyses of AKI associated with mortality at 30 days - sensitivity analysis
AKI (all stages)	2.67	2.14–3.34	0.0000		n/a
No AKI	Ref	Ref	Ref	Ref	Ref	Ref
AKI stage 1	2.26	1.72–2.97	0.0000	1.58	1.18–2.12	0.0020
AKI stage 2	4.25	2.91–6.2	0.0000	2.61	1.74–3.92	0.0000
AKI stage 3	2.77	2.09–3.67	0.0000	2.95	2.14–4.06	0.0000

AKI acute kidney injury, HR hazard ratio, CI, confidence interval

^aVariables were entered into the model when the level of risk factor was less than 0.1

^badjusted for age, gender, comorbidities (chronic kidney disease, hypertension, cardiovascular disease, diabetes, malignancy, neurological disease, lung disease) and inflammatory markers (CRP, albumin, Neutrophil: Lymphocyte ratio)