Value of soluble TREM-1, procalcitonin, and C-reactive protein serum levels as biomarkers for detecting bacteremia among sepsis patients with new fever in intensive care units: a prospective cohort study

Abstract

Background: The purpose of this study was to explore the diagnostic value of soluble triggering receptor expressed on myeloid cells 1 (sTREM-1), procalcitonin (PCT), and C-reactive protein (CRP) serum levels for differentiating sepsis from SIRS, identifying new fever caused by bacteremia, and assessing prognosis when new fever occurred.

Methods: We enrolled 144 intensive care unit (ICU) patients: 60 with systemic inflammatory response syndrome (SIRS) and 84 with sepsis complicated by new fever at more than 48 h after ICU admission. Serum sTREM-1, PCT, and CRP levels were measured on the day of admission and at the occurrence of new fever (>38.3°C) during hospitalization. Based on the blood culture results, the patients were divided into a blood culture-positive bacteremia group (33 patients) and blood culture-negative group (51 patients). Based on 28-day survival, all patients, both blood culture-positive and -negative, were further divided into survivor and nonsurvivor groups.

Results: On ICU day 1, the sepsis group had higher serum sTREM-1, PCT, and CRP levels compared with the SIRS group (P <0.05). The areas under the curve (AUC) for these indicators were 0.868 (95% CI, 0.798-0.938), 0.729 (95% CI, 0.637-0.821), and 0.679 (95% CI, 0.578-0.771), respectively. With 108.9 pg/ml as the cut-off point for serum sTREM-1, sensitivity was 0.83 and specificity was 0.81. There was no statistically significant difference in serum sTREM-1 or PCT levels between the blood culture-positive and -negative bacteremia groups with ICU-acquired new fever. However, the nonsurvivors in the blood culture-positive bacteremia group had higher levels of serum sTREM-1 and PCT (P <0.05), with a prognostic AUC for serum sTREM-1 of 0.868 (95% CI, 0.740-0.997).

Conclusions: Serum sTREM-1, PCT, and CRP levels each have a role in the early diagnosis of sepsis. Serum sTREM-1, with the highest sensitivity and specificity of all indicators studied, is especially notable. sTREM-1, PCT, and CRP levels are of no use in determining new fever caused by bacteremia in ICU patients, but sTREM-1 levels reflect the prognosis of bacteremia.

Trial registration: ClinicalTrial.gov identifier NCT01410578.

Figure 1

Profiles of patients enrolled in our study

Figure 2

Comparison of diagnostic values for sepsis. The diagnostic values of sTREM-1, CRP, and PCT levels; WBC count; and APACHE II score for sepsis on the day ICU admission were compared. The dots denote individual values, and the bars denote means

Figure 3

ROC curves for sepsis versus SIRS. Shown are the ROC curves for sTREM-1, CRP, and PCT levels and APACHE II score for distinguishing sepsis from SIRS

Figure 4

Causes of bacteremia. Shown are the relative proportions of causes of bacteremia from 33 positive blood cultures

Figure 5

Comparison of diagnostic values for bacteremia. The diagnostic values of sTREM-1, CRP, and PCT levels and WBC count for bacteremia were compared. The dots denote individual values, and the bars denote means

Figure 6

ROC curves for nonsurvivors versus blood culture-positives. Shown are the ROC curves for sTREM-1 and PCT for distinguishing nonsurvivors from blood culture-positives