Impact of early ICU admission on outcome of critically ill and critically ill cancer patients: A systematic review and meta-analysis.

Objective: Prognostic impact of early ICU admission remains controversial. The aim of this review was to investigate the impact of early ICU admission in the general ICU population and in critically ill cancer patients and to report level of evidences of this later.

Methods: Systematic review and meta-analysis performed on articles published between 1970 and 2017. Two authors extracted data. Influence of early ICU admission on mortality is reported as Risk Ratio (95%CI) using both fixed and random-effects model.

Data Synthesis: For general ICU population, 31 studies reporting on 73,213 patients were included (including 66,797 patients with early ICU admission) and for critically ill cancer patients 14 studies reporting on 2414 patients (including 1272 with early ICU admission) were included. Early ICU admission was associated with decreased mortality using a random effect model (RR 0.65; 95% confidence interval 0.58-0.73; I = 66%) in overall ICU population as in critically ill cancer patients (RR 0.69; 95% confidence interval 0.52-0.90; I = 85%). To explore heterogeneity, a meta-regression was performed. Characteristics of the trials (prospective vs. retrospective, monocenter vs. multicenter) had no impact on findings. Publication after 2010 (median publication period) was associated with a lower effect of early ICU admission (estimate 0.37; 95%CI 0.14-0.60; P = 0.002) in the general ICU population. A significant publication bias was observed.

Conclusion: Theses results suggest that early ICU admission is associated with decreased mortality in the general ICU population and in CICP. These results were however obtained from high risk of bias studies and a high heterogeneity was noted. Systematic review registration: PROSPERO 2018 CRD42018094828.