Proinflammatory Cytokine Levels in Sepsis and in Health and TNFα Association with Sepsis Mortality and patient characteristics: a Systematic Review and Meta-analysis

Abstract

AbstractBackgroundSepsis is a global health problem associated with significant morbidity and mortality. Detrimental sepsis effects are attributed to a “cytokine storm.” However, anti-cytokine therapies have failed to lower sepsis mortality. We aim to characterize levels of key cytokines in sepsis patients and healthy controls and relate TNFα levels to patient characteristics and outcomes.MethodsWe performed a systematic review and meta-analysis. Medline, Embase, Cochrane Library, and Web of Science Core Collection databases were searched from 1985 to May 2020 for studies in English. We included randomized controlled trials (RCTs), controlled trials, cohort studies, case series, and cross-sectional studies that reported mean levels of cytokines in the circulation thought to be relevant for sepsis pathogenesis. We also evaluated concentrations of these cytokines in healthy persons. Quality in Prognosis Studies tool was used to assess the methodological quality of included studies. We extracted summary data from published reports. Data analyses were performed using a random-effects model to estimate pooled odds ratios (OR) with 95% confidence intervals for cytokine levels and mortality. This systematic review is registered in PROSPERO (CRD42020179800).FindingsWe identified 3654 records, and 104 studies were included with a total of 3250 participants. The pooled estimated mean TNFα concentration in sepsis patients was 58.4 pg/ml (95% Confidence Interval or CI 39.8-85.8 pg/ml) and 5.5 pg/ml (95% CI 3.8-8.0 pg/ml) in healthy controls. Pooled estimate means for IL-1β and IFNγ in sepsis patients were 21.8 pg/ml and 63.3 pg/ml, respectively. Elevated TNFα concentrations associated with increased 28-day sepsis mortality (p=0.001). In subgroup analyses, TNFα levels did not relate to sepsis source, sepsis severity, or sequential organ failure assessment (SOFA) score.InterpretationTNFα concentration in sepsis is increased approximately 10-fold compared to healthy persons, and TNFα associated with sepsis mortality but not with sepsis severity. The concept that elevated cytokines cause sepsis should be revisited in the context of these data.FundingNone.