Table 3.

Multivariate Cox regression analysis between quartiles of the systemic immune-inflammation index and 30-day mortality.

Variable	Nonadjusted (HR (95% CI), P)	Adjusted I (HR (95% CI), P)	Adjusted II (HR (95% CI), P)
30-day SII (quartile)
Q1	1 (Ref)	1 (Ref)	1 (Ref)
Q2	1.03 (0.63–1.67), 0.91	1.08 (0.66–1.75) 0.765	1.3 (0.79–2.12) 0.297
Q3	1.42 (0.91–2.21), 0.123	1.61 (1.03–2.51) 0.037	1.86 (1.18–2.93) 0.007
Q4	2.28 (1.51–3.43), <0.001	2.56 (1.69–3.86) <0.001	2.72 (1.78–4.17) <0.001
Log SII	2.35 (1.63–3.37), <0.001	2.51 (1.76–3.59) <0.001	2.43 (1.71–3.45) <0.001
90-day SII (quartile)
Q1	1 (Ref)	1 (Ref)	1 (Ref)
Q2	1 (0.63–1.58), 0.99	1.04 (0.65–1.65), 0.884	1.25 (0.78–2), 0.355
Q3	1.45 (0.95–2.21), 0.081	1.68 (1.1–2.57), 0.016	1.87 (1.22–2.87), 0.004
Q4	2.14 (1.44–3.17), <0.001	2.45 (1.65–3.64), <0.001	2.63 (1.74–3.96), <0.001
Log SII	2 (1.56–3.11), <0.001	2.42 (1.72–3.41), <0.001	1.92 (1.36–2.72), <0.001
P for trend	<0.001	<0.001	<0.001

Nonadjusted: no covariates were adjusted; adjusted I: we only adjusted for age and sex; adjusted II: we adjusted for age, gender, heart rate, respiratory rate, Charlson comorbidity, anion gap, bicarbonate, glucose, warfarin, NOAC, antiplatelet agents, PEGJ, mechanical ventilation, SOFA, and LOS.ICU. HR, hazard ratio; CI, confidence interval; Ref, reference.