Integrating serum ferritin and neutrophil-to-lymphocyte ratio with Sequential Organ Failure Assessment score improves mortality prediction in sepsis

Table 2 Baseline characteristics, n (%)

Characteristic	All patients (n = 1954)	Survivors (n = 1426)	Deaths (n = 528)	P value
Demographics
Age, years (mean ± SD)	61.6 ± 15.3	59.4 ± 15.2	67.7 ± 13.7	< 0.001
Sex				0.364
Male	1082 (55.4)	778 (54.6)	304 (57.6)
Female	872 (44.6)	648 (45.4)	224 (42.4)
BMI, kg/m2 (mean ± SD)	28.3 ± 7.9	28.5 ± 8.0	27.8 ± 7.7	0.107
Comorbidities
Charlson comorbidity index (mean ± SD)	2.2 ± 2.2	2.0 ± 2.1	2.8 ± 2.4	< 0.001
Hypertension	823 (42.1)	566 (39.7)	257 (48.7)	< 0.001
Diabetes mellitus	517 (26.5)	362 (25.4)	155 (29.4)	0.079
COPD	304 (15.6)	198 (13.9)	106 (20.1)	0.001
Chronic kidney disease	386 (19.8)	247 (17.3)	139 (26.3)	< 0.001
Chronic liver disease	215 (11.0)	137 (9.6)	78 (14.8)	0.001
Malignancy	293 (15.0)	177 (12.4)	116 (22.0)	< 0.001
Source of infection1				0.019
a: Pulmonary	809 (41.4)	565 (39.6)	244 (46.2)
b: Urinary	421 (21.5)	333 (23.4)	88 (16.7)
c: Abdominal	389 (19.9)	288 (20.2)	101 (19.1)
d: Bloodstream	215 (11.0)	147 (10.3)	68 (12.9)
e: Other/unknown	120 (6.1)	93 (6.5)	27 (5.1)
Clinical parameters at admission
Systolic BP, mmHg (mean ± SD)	118.7 ± 24.5	121.8 ± 22.9	110.4 ± 26.7	< 0.001
MAP, mmHg (mean ± SD)	78.5 ± 16.0	80.6 ± 14.9	73.0 ± 17.2	< 0.001
Heart rate, bpm (mean ± SD)	101.3 ± 21.8	100.1 ± 20.9	104.5 ± 23.7	< 0.001
Respiratory rate, breaths/min (mean ± SD)	22.8 ± 6.2	22.0 ± 5.8	24.9 ± 6.7	< 0.001
Temperature, °C (mean ± SD)	37.3 ± 1.1	37.4 ± 1.0	37.0 ± 1.2	< 0.001
SpO2, % (mean ± SD)	94.8 ± 4.7	95.4 ± 4.2	93.2 ± 5.5	< 0.001
Laboratory values
Ferritin (mean ± SD) (ng/mL)	1480.9 ± 2912.1	1196.4 ± 2423.8	2223.5 ± 3766.6	< 0.001
NLR (mean ± SD)	31.6 ± 95.3	24.7 ± 85.6	50.1 ± 114.4	< 0.001
Hemoglobin, g/dL (mean ± SD)	11.2 ± 2.3	11.4 ± 2.2	10.6 ± 2.3	< 0.001
WBC count, × 10³/μL (mean ± SD)	15.8 ± 11.2	15.2 ± 10.6	17.3 ± 12.4	< 0.001
Platelet count, × 10³/μL (mean ± SD)	217.3 ± 119.0	228.9 ± 119.8	186.8 ± 111.2	< 0.001
Creatinine, mg/dL (mean ± SD)	1.7 ± 1.5	1.5 ± 1.3	2.1 ± 1.8	< 0.001
Total bilirubin, mg/dL (mean ± SD)	1.4 ± 2.5	1.2 ± 2.1	2.0 ± 3.2	< 0.001
Lactate, mmol/L (mean ± SD)	2.9 ± 2.4	2.4 ± 1.8	4.1 ± 3.2	< 0.001
Interventions
Invasive ventilation	782 (40.0)	483 (33.9)	299 (56.6)	< 0.001
Vasopressor use	897 (45.9)	560 (39.3)	337 (63.8)	< 0.001
Dialysis	326 (16.7)	198 (13.9)	128 (24.2)	< 0.001
Outcomes
ICU stay duration, days (mean ± SD)	6.3 ± 7.8	5.9 ± 7.2	7.4 ± 9.1	0.001
Hospital stay duration, days (mean ± SD)	14.2 ± 13.4	15.8 ± 13.7	10.1 ± 11.5	< 0.001

¹P values represent overall comparison across categories using the χ² test.

BMI: Body mass index; BP: Blood pressure; COPD: Chronic obstructive pulmonary disease; ICU: Intensive care unit; IQR: Interquartile range; MAP: Mean arterial pressure; NLR: Neutrophil-lymphocyte ratio; SpO_2: Peripheral oxygen saturation; SD: Standard deviation; WBC: White blood cell.