Prognostic Value of Procalcitonin, C-Reactive Protein, and Lactate Levels in Emergency Evaluation of Cancer Patients with Suspected Infection

Abstract

Cancer patients have increased risk of infections, and often present to emergency departments with infection-related problems where physicians must make decisions based on a snapshot of the patient's condition. Although C-reactive protein, procalcitonin, and lactate are popular biomarkers of sepsis, their use in guiding emergency care of cancer patients with infections is unclear. Using these biomarkers, we created a prediction model for short-term mortality in cancer patients with suspected infection. We retrospectively analyzed all consecutive patients who visited the emergency department of MD Anderson Cancer Center between 1 April 2018 and 30 April 2019. A clinical decision model was developed using multiple logistic regression for various clinical and laboratory biomarkers; coefficients were used to generate a prediction score stratifying patients into four groups according to their 14-day mortality risk. The prediction score had an area under the receiver operating characteristic curve value of 0.88 (95% confidence interval 0.85-0.91) in predicting 14-day mortality. The prediction score also accurately predicted intensive care unit admission and 30-day mortality. Our simple new scoring system for mortality prediction, based on readily available clinical and laboratory data, including procalcitonin, C-reactive protein, and lactate, can be used in emergency departments for cancer patients with suspected infection.

Keywords: C-reactive protein; emergency department; infectious oncologic emergencies; lactic acid; procalcitonin; sepsis.

Figure 1

Variation of infection/sepsis biomarker levels stratified by quick sequential organ failure assessment (qSOFA) scores and bacterial blood culture results in cancer patients presenting to the emergency department with suspected infection. Upper panel: Distribution of (A) lactate, (B) C-reactive protein (CRP), and (C) procalcitonin levels by qSOFA score. A one-way analysis of variance followed by the post hoc Tukey test was used for statistical analysis. Lower panel: Distribution of (D) lactate, (E) CRP, and (F) procalcitonin levels for positive and negative bacterial blood culture results. The Wilcoxon-Mann-Whitney test was used for statistical analysis. * p < 0.05; ** p < 0.01; *** p < 0.001.

Figure 2

Classification of 14-day mortality using common clinical and laboratory variables among cancer patients presenting to the emergency department with suspected infection. Abbreviations: LDH, lactate dehydrogenase; BUN, blood urea nitrogen; AST, aspartate aminotransferase; WBC, white blood cell count; ANC, absolute neutrophil count; GFR, glomerular filtration rate; SpO2, oxygen saturation.

Figure 3

Fourteen-day mortality rates for different prediction scores and risk groups among cancer patients presenting to the emergency department with suspected infection.

Figure 4

Algorithm of the final prediction score for 14-day mortality among cancer patients presenting to the emergency department with suspected infection. qSOFA, quick sequential organ failure assessment; CRP, C-reactive protein; LDH, lactate dehydrogenase.