Dataset Information

Populations at risk for severe or complicated Avian Influenza H5N1: a systematic review and meta-analysis.

ABSTRACT:

Background

Little is known about risk factors for severe outcomes in patients infected with H5N1 and no systematic review has been conducted. Understanding risk factors is an important step for prioritizing prophylaxis or treatment in the event of a pandemic.

Objectives

To systematically evaluate risk factors for severe outcomes in patients with avian influenza H5N1 infection.

Data sources

MEDLINE, EMBASE, CINAHL, GlobalHealth, and CENTRAL through March 2011.

Eligibility criteria for selecting studies

Observational studies of any design published in English, French, Spanish, German or Korean that reported on risk factor-outcome combinations of interest in participants with confirmed H5N1 infections. Outcomes considered included death, ventilator support, hospital and ICU admission, pneumonia, and composite outcomes.

Study appraisal

Risk of bias was assessed using the Newcastle-Ottawa scale (NOS).

Results

We identified 20 studies reporting on 999 patients infected with H5N1. The majority of studies (n?=?14, 70%) were at intermediate risk of bias, i.e. 4-6 points on the NOS. Females were at increased risk of death (OR 1.75, 95% CI 1.27-2.44), while young age, in particular <5 years of age (OR 0.44, 95% CI 0.25-0.79 for death), was protective. Data on traditional risk factors was scarce and requires further studies. Another major limitation in the published literature was lack of adjustment for confounders.

Interpretation

Females were at increased risk for complications following H5N1 infection while young age protected against severe outcomes. Research on traditional risk factors was limited and is required.

SUBMITTER: Mertz D

PROVIDER: S-EPMC3948335 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Populations at risk for severe or complicated Avian Influenza H5N1: a systematic review and meta-analysis.

Mertz Dominik D Kim Tae Hyong TH Johnstone Jennie J Lam Po-Po PP Science Michelle M Kuster Stefan P SP Fadel Shaza A SA Tran Dat D Fernandez Eduardo E Bhatnagar Neera N Loeb Mark M

PloS one 20140306 3

<h4>Background</h4>Little is known about risk factors for severe outcomes in patients infected with H5N1 and no systematic review has been conducted. Understanding risk factors is an important step for prioritizing prophylaxis or treatment in the event of a pandemic.<h4>Objectives</h4>To systematically evaluate risk factors for severe outcomes in patients with avian influenza H5N1 infection.<h4>Data sources</h4>MEDLINE, EMBASE, CINAHL, GlobalHealth, and CENTRAL through March 2011.<h4>Eligibility ...[more]

PMID: 24603885

Similar Datasets

Project description:ObjectiveTo evaluate risk factors for severe outcomes in patients with seasonal and pandemic influenza.DesignSystematic review.Study selectionObservational studies reporting on risk factor-outcome combinations of interest in participants with influenza. Outcomes included death, ventilator support, admission to hospital, admission to an intensive care unit, pneumonia, and composite outcomes.Data sourcesMedline, Embase, CINAHL, Global Health, and the Cochrane Central Register of Controlled Trials to March 2011.Risk of bias assessmentNewcastle-Ottawa scale to assess the risk of bias. GRADE framework to evaluate the quality of evidence.Results63 537 articles were identified of which 234 with a total of 610 782 participants met the inclusion criteria. The evidence supporting risk factors for severe outcomes of influenza ranged from being limited to absent. This was particularly relevant for the relative lack of data for non-2009 H1N1 pandemics and for seasonal influenza studies. Limitations in the published literature included lack of power and lack of adjustment for confounders was widespread: adjusted risk estimates were provided for only 5% of risk factor-outcome comparisons in 39 of 260 (15%) studies. The level of evidence was low for "any risk factor" (odds ratio for mortality 2.77, 95% confidence interval 1.90 to 4.05 for pandemic influenza and 2.04, 1.74 to 2.39 for seasonal influenza), obesity (2.74, 1.56 to 4.80 and 30.1, 1.74 to 2.39), cardiovascular diseases (2.92, 1.76 to 4.86 and 1.97, 1.06 to 3.67), and neuromuscular disease (2.68, 1.91 to 3.75 and 3.21, 1.84 to 5.58). The level of evidence was very low for all other risk factors. Some well accepted risk factors such as pregnancy and belonging to an ethnic minority group could not be identified as risk factors. In contrast, women who were less than four weeks post partum had a significantly increased risk of death from pandemic influenza (4.43, 1.24 to 15.81).ConclusionThe level of evidence to support risk factors for influenza related complications is low and some well accepted risk factors, including pregnancy and ethnicity, could not be confirmed as risks. Rigorous and adequately powered studies are needed.

Project description:BackgroundThe threat posed by highly pathogenic avian influenza A H5N1 viruses to humans remains significant, given the continued occurrence of sporadic human cases (499 human cases in 15 countries) with a high case fatality rate (approximately 60%), the endemicity in poultry populations in several countries, and the potential for reassortment with the newly emerging 2009 H1N1 pandemic strain. Therefore, we review risk factors for H5N1 infection in humans.Methods and findingsSeveral epidemiologic studies have evaluated the risk factors associated with increased risk of H5N1 infection among humans who were exposed to H5N1 viruses. Our review shows that most H5N1 cases are attributed to exposure to sick poultry. Most cases are sporadic, while occasional limited human-to-human transmission occurs. The most commonly identified factors associated with H5N1 virus infection included exposure through contact with infected blood or bodily fluids of infected poultry via food preparation practices; touching and caring for infected poultry; [corrected] exposure to H5N1 via swimming or bathing in potentially virus laden ponds; and exposure to H5N1 at live bird markets.ConclusionsResearch has demonstrated that despite frequent and widespread contact with poultry, transmission of the H5N1 virus from poultry to humans is rare. Available research has identified several risk factors that may be associated with infection including close direct contact with poultry and transmission via the environment. However, several important data gaps remain that limit our understanding of the epidemiology of H5N1 in humans. Although infection in humans with H5N1 remains rare, human cases continue to be reported and H5N1 is now considered endemic among poultry in parts of Asia and in Egypt, providing opportunities for additional human infections and for the acquisition of virus mutations that may lead to more efficient spread among humans and other mammalian species. Collaboration between human and animal health sectors for surveillance, case investigation, virus sharing, and risk assessment is essential to monitor for potential changes in circulating H5N1 viruses and in the epidemiology of H5N1 in order to provide the best possible chance for effective mitigation of the impact of H5N1 in both poultry and humans.DisclaimerThe opinions expressed in this article are those of the authors and do not necessarily reflect those of the institutions or organizations with which they are affiliated.

Dataset Information

Populations at risk for severe or complicated Avian Influenza H5N1: a systematic review and meta-analysis.

Background

Objectives

Data sources

Eligibility criteria for selecting studies

Study appraisal

Results

Interpretation

Publications

Populations at risk for severe or complicated Avian Influenza H5N1: a systematic review and meta-analysis.

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