A systematic review and meta-analysis of patient data from the West Africa (2013-16) Ebola virus disease epidemic

Abstract

Background: Over 28 000 individuals were infected with Ebola virus during the West Africa (2013-2016) epidemic, yet there has been criticism of the lack of robust clinical descriptions of Ebola virus disease (EVD) illness from that outbreak.

Objectives: To perform a meta-analysis of published data from the epidemic to describe the clinical presentation, evolution of disease, and predictors of mortality in individuals with EVD. To assess the quality and utility of published data for clinical and public health decision-making.

Data sources: Primary articles available in PubMed and published between January 2014 and May 2017.

Eligibility: Studies that sequentially enrolled individuals hospitalized for EVD and that reported acute clinical outcomes.

Methods: We performed meta-analyses using random-effect models and assessed heterogeneity using the I² method. We assessed data representativeness by comparing meta-analysis estimates with WHO aggregate data. We examined data utility by examining the availability and compatibility of data sets.

Results: In all, 3653 articles were screened and 34 articles were included, representing 16 independent cohorts of patients (18 overlapping cohorts) and at least 6168 individuals. The pooled estimate for case fatality rate was 51% (95% CI 46%-56%). However, pooling of estimates for clinical presentation, progression, and predictors of mortality in individuals with EVD were hampered by significant heterogeneity, and inadequate data on clinical progression. Our assessment of data quality found that heterogeneity was largely unexplained, and data availability and compatibility were poor.

Conclusions: We have quantified a missed opportunity to generate reliable estimates of the clinical manifestations of EVD during the West Africa epidemic. Clinical data standards and data capture platforms are urgently needed.

Keywords: Ebola; Ebola virus disease; emerging infection; epidemic; outbreak; viral hemorrhagic.

Fig. 1

Summary of article selection process.

Fig. 2

Meta-analysis of proportion of individuals with Ebola virus disease (EVD) presenting with a symptom compared with reference data. Blue represents a meta-analysis estimate with low or moderate heterogeneity for the pooled estimate, red represents a meta-analysis estimate with high heterogeneity. Grey is WHO reference data. All estimates are shown with their 95% CI.

Fig. 3

Meta-analysis of the relative risk of death in individuals with Ebola virus disease (EVD) presenting with a symptom on admission, compared with symptom absence, and showing comparison reference data. Blue represents a meta-analysis estimate with low or moderate heterogeneity for the pooled estimate, red represents a meta-analysis estimate with high heterogeneity. Grey is WHO reference data. All estimates are shown with their 95% CI.

Fig. 4

Funnel plot of case fatality rate (CFR) by country. The horizontal red line is a reference value that depicts the overall CFR for hospitalized patients during the outbreak reported by WHO, with 95% and 99.8% Cl.

Fig. 5

Reporting of predictors of mortality for patients with laboratory confirmed Ebola virus disease (EVD). Cells with a red tab reflect a complex relationship (such as statistical significance for only a subset of data). Asterisk indicates the it includes if association on univariate analysis is not supported by multivariate analysis. VL, viral load; Ct, cycle threshold; Rx, treatment.