Biomarkers of Inflammation and Inflammation-Related Indexes upon Emergency Department Admission Are Predictive for the Risk of Intensive Care Unit Hospitalization and Mortality in Acute Poisoning: A 6-Year Prospective Observational Study

Abstract

Patients poisoned with drugs and nonpharmaceutical substances are frequently admitted from the emergency department (ED) to a medical or ICU department. We hypothesized that biomarkers of inflammation and inflammation-related indexes based on the complete blood cell (CBC) count can identify acutely poisoned patients at increased risk for ICU hospitalization and death. We performed a 6-year prospective cohort study on 1548 adult patients. The demographic data, the levels of hs-CRP (high-sensitivity C-reactive protein), CBC, and inflammation-related indexes based on CBC counts were collected upon admission and compared between survivors and nonsurvivors, based on the poison involved. Both a multivariate logistic regression model with only significant univariate predictors and a model including univariate predictors plus each log-transformed inflammation-related indexes for mortality were constructed. The importance of the variables for mortality was graphically represented using the nomogram. hs-CRP (odds ratio (OR), 1.38; 95% CI, 1.16-1.65, p < 0.001 for log-transformed hs-CRP), red cell distribution width (RDW), neutrophil-lymphocyte ratio (NLR), and platelet-lymphocyte ratio (PLR) were significantly associated with the risk of ICU hospitalization, after multivariable adjustment. Only RDW, NLR, and monocyte-lymphocyte ratio (MLR) were significantly associated with mortality. The predictive accuracy for mortality of the models which included either NLR (AUC 0.917, 95% CI 0.886-0.948) or MLR (AUC 0.916, 95% CI 0.884-0.948) showed a high ability for prognostic detection. The use of hs-CRP, RDW, NLR, and MLR upon ED admission are promising screening tools for predicting the outcomes of patients acutely intoxicated with undifferentiated poisons.

Figure 1

Study flow diagram.

Figure 2

Box plot demonstrating the effect of admission RDW on mortality in patients poisoned with pharmaceutical agents (a) and in patients poisoned with nonpharmaceutical substances (b). Values are median and interquartile range; dots represent outliers; ∗ represent extreme values.

Figure 3

Box plot demonstrating the effect of admission NLR on mortality in patients poisoned with pharmaceutical agents (a) and in patients poisoned with combination of poisons (b). Values are median and interquartile range; dots represent outliers; ∗ represent extreme values.

Figure 4

Receiver operating characteristic (ROC) curves compared the diagnostic accuracy of the model predicting the need for ICU hospitalization.

Figure 5

Nomogram constructed for model 1 included age, arterial lactate upon ED arrival, GCS score, and RDW.

Figure 6

(a) Nomogram constructed for model 2 included all variables in model 1 and NLR. (b) Nomogram constructed for model 5 included all variables in model 1 and MLR.

Figure 7

Receiver operating characteristic (ROC) curves compares the diagnostic accuracy of the five models constructed (AUC and 95% CI are presented for each model).