Giuseppe
Emeritus
[Source: British Medical Journal, full page: (LINK). Abstract, edited.]
Research
Populations at risk for severe or complicated influenza illness: systematic review and meta-analysis
<CITE><ABBR>BMJ </ABBR>2013; 347 doi: http://dx.doi.org/10.1136/bmj.f5061 (Published 23 August 2013)</CITE>
<CITE></CITE>
<CITE>Cite this as: <ABBR>BMJ</ABBR> 2013;347:f5061</CITE>
<CITE></CITE>
<CITE></CITE>Dominik Mertz, assistant professor 1 2, Tae Hyong Kim, researcher 2, Jennie Johnstone, researcher 2, Po-Po Lam, researcher 3 4, Michelle Science, staff physician 5, Stefan P Kuster, staff physician 6, Shaza A Fadel, researcher 4, Dat Tran, assistant professor 5, Eduardo Fernandez, researcher 2, Neera Bhatnagar, librarian 7, Mark Loeb, professor 2 8 9
Author Affiliations: <SUP>1</SUP>Department of Medicine, McMaster University, Hamilton, ON, Canada <SUP>2</SUP>Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton <SUP>3</SUP>Mount Sinai Hospital, Toronto, ON, Canada <SUP>4</SUP>Division of Epidemiology, Dalla Lana School of Public Health, University of Toronto, Toronto <SUP>5</SUP>Department of Pediatrics, The Hospital for Sick Children, University of Toronto, ON, Canada <SUP>6</SUP>University Hospital and University of Zurich, Zurich, Switzerland <SUP>7</SUP>Health Sciences Library, McMaster University, Hamilton <SUP>8</SUP>Department of Pathology and Molecular Medicine, McMaster University, Hamilton <SUP>9</SUP>Michael G DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton
Correspondence to: M Loeb Department of Pathology and Molecular Medicine, McMaster University MDCL 3203, 1200 Main St. W, Hamilton, ON, Canada L8N 3Z5 loebm@mcmaster.ca
Accepted 22 July 2013
Abstract
Objective
To evaluate risk factors for severe outcomes in patients with seasonal and pandemic influenza.
Design
Systematic review.
Study selection
Observational 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 sources
Medline, Embase, CINAHL, Global Health, and the Cochrane Central Register of Controlled Trials to March 2011.
Risk of bias assessment
Newcastle-Ottawa scale to assess the risk of bias. GRADE framework to evaluate the quality of evidence.
Results
63 537 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).
Conclusion
The 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.
-
--------
Research
Populations at risk for severe or complicated influenza illness: systematic review and meta-analysis
<CITE><ABBR>BMJ </ABBR>2013; 347 doi: http://dx.doi.org/10.1136/bmj.f5061 (Published 23 August 2013)</CITE>
<CITE></CITE>
<CITE>Cite this as: <ABBR>BMJ</ABBR> 2013;347:f5061</CITE>
<CITE></CITE>
<CITE></CITE>Dominik Mertz, assistant professor 1 2, Tae Hyong Kim, researcher 2, Jennie Johnstone, researcher 2, Po-Po Lam, researcher 3 4, Michelle Science, staff physician 5, Stefan P Kuster, staff physician 6, Shaza A Fadel, researcher 4, Dat Tran, assistant professor 5, Eduardo Fernandez, researcher 2, Neera Bhatnagar, librarian 7, Mark Loeb, professor 2 8 9
Author Affiliations: <SUP>1</SUP>Department of Medicine, McMaster University, Hamilton, ON, Canada <SUP>2</SUP>Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton <SUP>3</SUP>Mount Sinai Hospital, Toronto, ON, Canada <SUP>4</SUP>Division of Epidemiology, Dalla Lana School of Public Health, University of Toronto, Toronto <SUP>5</SUP>Department of Pediatrics, The Hospital for Sick Children, University of Toronto, ON, Canada <SUP>6</SUP>University Hospital and University of Zurich, Zurich, Switzerland <SUP>7</SUP>Health Sciences Library, McMaster University, Hamilton <SUP>8</SUP>Department of Pathology and Molecular Medicine, McMaster University, Hamilton <SUP>9</SUP>Michael G DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton
Correspondence to: M Loeb Department of Pathology and Molecular Medicine, McMaster University MDCL 3203, 1200 Main St. W, Hamilton, ON, Canada L8N 3Z5 loebm@mcmaster.ca
Accepted 22 July 2013
Abstract
Objective
To evaluate risk factors for severe outcomes in patients with seasonal and pandemic influenza.
Design
Systematic review.
Study selection
Observational 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 sources
Medline, Embase, CINAHL, Global Health, and the Cochrane Central Register of Controlled Trials to March 2011.
Risk of bias assessment
Newcastle-Ottawa scale to assess the risk of bias. GRADE framework to evaluate the quality of evidence.
Results
63 537 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).
Conclusion
The 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.
-
--------