Patient baseline characteristics
A total of 168 septic patients who were admitted to the ED were recruited, including 54 patients in the non-survival group (death group) and 114 patients in the survival group (discharge group). There were 101 males and 67 females, with no significant difference in gender between the two groups (P = 0.604). The median age of the survival was 69.0 (63, 80) and that of the non-survival group was 83 (74, 87), which differed significantly (P<0.001). Meanwhile, SOFA and APACHE II scores were significantly higher in the death group, and GCS scores were significantly higher in the survival group (P<0.001). The non-survival group exhibited higher respiratory and heart rates and a lower diastolic systolic blood pressure than the survival group, with statistically significant differences (all P<0.05). The incidence of coronary heart disease was higher in the death group than in the discharge group, with a statistically significant difference (P<0.05). However, no significant difference in the occurrence of diabetes, hypertension and chronic obstructive pulmonary disease was found between the two groups (all P>0.05). Patient baseline characteristics are summarized in Table 1.
Laboratory data analysis
LBP and lactate were higher in the death group than in the discharge group (P<0.001). Albumin (ALB) levels were lower in the death group than in the survival group, with significant differences (P<0.001). In addition, the white blood cell count, absolute neutrophil value, CRP and blood urea nitrogen were higher in the death group than in the survival group, with a statistically significant difference (P<0.05). However, no significant difference in absolute PCT, sodium, potassium and lymphocytes was detected between the two groups (P>0.05). More detailed results are shown in Table 2.
Multivariate regression analysis
We performed logistic multivariate regression analysis on indicators that showed significant results from univariate regression analysis. The results revealed that the APACHE II score (odds ratio [OR] = 1.264, 95% confidence interval [CI]: 1.009-1.584, P = 0.042), SOFA score (OR = 1.509, 95% CI: 1.177-1.936, P = 0.001), LBP (OR = 1.235, 95% CI: 1.109-1.376, P<0.001) and ALB (OR = 0.732, 95% CI: 0.594-0.901, P=0.003) were independent risk factors affecting the prognosis of patients with sepsis (Table 3).
ROC curve analysis
The ROC curve was plotted to evaluate the diagnostic performance of various statistically significant indicators in logistic multivariate regression analysis. The ROC curve analysis revealed that area under the curve (AUC) values for the APACHE II score, SOFA score, LBP, ALB, APACHE II+LBP and SOFA+LBP were 0.874 (95% CI: 0.821-0.926), 0.82 (95%CI: 0.754-0.886), 0.801 (95% CI: 0.736-0.866), 0.781 (95% CI: 0.711-0.852), 0.936 (95% CI: 0.9-0.971) and 0.889 (95% CI: 0.836-0.942), respectively. Notably, the AUC values of the APACHE II score, SOFA score, LBP, APACHE II+LBP and SOFA+LBP were all greater than 0.8, among which the AUC values of APACHE II score and LBP were the largest (AUC = 0.936). APACHE II+LBP and LBP had the highest sensitivity (both 0.963), while SOFA+LBP had the highest specificity (0.939). The cut-off values, Youden index and ROC plots of each index are shown in Table 4 and Figure 1.
Table 1 Baseline characteristics of the study population
APACHE II, Acute Physiology and Chronic Health Evaluation; SOFA, Sequential Organ Failure
Assessment; GCS, Glasgow Coma Scale; P<0.05 indicates statistical significance.
Table 2 Laboratory variables of the study population
WBC, white blood cell; LYM, lymphocyte; NEU, neutrophil; Abs, absolute value; CRP, C-reactive protein; PCT, procalcitonin; LBP, lipopolysaccharide-binding protein; Lac, lactic acid; BUN, blood urea nitrogen; Na, serum sodium; K, serum potassium; ALB, albumin; P < 0:05 indicates statistical significance.
Table 3 Multivariate regression analysis
APACHE II, Acute Physiology and Chronic Health Evaluation; SOFA, Sequential Organ Failure Assessment; GCS, Glasgow Coma Scale; CHD, coronary heart disease; SE, standard error; df, degree of freedom; CI, confidence interval; LL, lower limit; UL, upper limit; Sig., statistically significant results.
Table 4 Receiver operating characteristic curve analysis
AUC, area under the curve; CI, confidence interval; APACHE II, Acute Physiology and Chronic Health Evaluation; SOFA, Sequential Organ Failure Assessment; LBP, lipopolysaccharide-binding protein; ALB, albumin