The prognostic performance of the complement system in septic patients in emergency department: a cohort study

Circulating Complement C3-Alpha Chain Levels Predict Survival of Septic Shock Patients

BACKGROUND

Circulating complement C3 fragments released during septic shock might contribute to the development of complications such as profound hypotension and disseminated intravascular coagulation. The role of C3 in the course of septic shock varies in the literature, possibly because circulating C3 exists in different forms indistinguishable via traditional ELISA-based methods. We sought to test the relationship between C3 forms, measured by Western blotting with its associated protein size differentiation feature, and clinical outcomes.

METHODS

Secondary analysis of two prospective cohorts of patients with septic shock: a discovery cohort of 24 patents and a validation cohort of 181 patients. C3 levels were measured by Western blotting in both cohorts using blood obtained at enrollment. Differences between survivors and non-survivors were compared, and the independent prognostic values of C3 forms were assessed.

RESULTS

In both cohorts there were significantly lower levels of the C3-alpha chain in non-survivors than in survivors, and persisted after controlling for sequential organ failure assessment score. Area under the receiver operating characteristics to predict survival was 0.65 (95% confidence interval: 0.56-0.75). At a best cutoff value (Youden) of 970.6 μg/mL, the test demonstrated a sensitivity of 68.5% and specificity of 61.5%. At this cutoff point, Kaplan-Meier survival analysis showed that patients with lower levels of C3-alpha chain had significantly lower survival than those with higher levels (P < 0.001).

CONCLUSION

Circulating C3-alpha chain levels is a significant independent predictor of survival in septic shock patients.

Performance of the MEDS score in predicting mortality among emergency department patients with a suspected infection: a meta-analysis

OBJECTIVES

To carry out a meta-analysis to examine the prognostic performance of the Mortality in Emergency Department Sepsis (MEDS) score in predicting mortality among emergency department patients with a suspected infection.

METHODS

Electronic databases-PubMed, Embase, Scopus, EBSCO and the Cochrane Library-were searched for eligible articles from their respective inception through February 2019. Sensitivity, specificity, likelihood ratios and receiver operator characteristic area under the curve were calculated. Subgroup analyses were performed to explore the prognostic performance of MEDS in selected populations.

RESULTS

We identified 24 studies involving 21 246 participants. The pooled sensitivity of MEDS to predict mortality was 79% (95% CI 72% to 84%); specificity was 74% (95% CI 68% to 80%); positive likelihood ratio 3.07 (95% CI 2.47 to 3.82); negative likelihood ratio 0.29 (95% CI 0.22 to 0.37) and area under the curve 0.83 (95% CI 0.80 to 0.86). Significant heterogeneity was seen among included studies. Meta-regression analyses showed that the time at which the MEDS score was measured and the cut-off value used were important sources of heterogeneity.

CONCLUSION

The MEDS score has moderate accuracy in predicting mortality among emergency department patients with a suspected infection. A study comparison MEDS and qSOFA in the same population is needed.

Components of the lectin pathway of complement activation in paediatric patients of intensive care units

Infections are a major cause of childhood mortality. We investigated components of the lectin pathway of complement activation in the context of sepsis at both genetic and protein levels in neonates, infants and older children. Major components of the lectin pathway and two genes for Toll-like receptors were studied in 87 neonates with confirmed sepsis and compared with 40 babies with infections who did not develop sepsis (disease controls) and 273 infection-free neonatal controls. A second cohort comprised 47 older children with sepsis and 87 controls. Low MBL-conferring genotypes (LXA/O+O/O) were more frequent in sepsis patients than in healthy controls but no significant differences in the frequency of SNPs of other lectin pathway genes (FCN1, FCN2, FCN3, MASP1/3, MASP2) or TLR receptor genes (TLR2, TLR4) were found. One case of primary MASP-2 deficiency was found among healthy pre-terms and one neonate suffering from SIRS was heterozygous for the rare FCN1 gene mutation, +6658 G>A. Generally, sepsis was associated with low serum MBL and low ficolin-2 concentrations on admission. Among neonates, ficolin-1 and MASP-2 levels were elevated in sepsis relative to healthy, but not disease, controls. Unlike neonates, ficolin-3 and MASP-2 levels were lower in older patients than in healthy controls while no difference was found for ficolin-1. With the possible exception of MBL, inherited lectin pathway insufficiencies do not seem to predispose to sepsis, rather changes in protein concentrations reflect alterations in disease course.