Predictors of Severe H1N1 Infection in Children
Predictors of Severe H1N1 Infection in Children
Objective. To identify historical and clinical findings at emergency department presentation associated with severe H1N1 outcome in children presenting with influenza-like illness.
Design. Multicentre retrospective case-control study.
Setting. 79 emergency departments of hospitals associated with the Pediatric Emergency Research Networks in 12 countries.
Participants. 265 children (<16 years), presenting between 16 April and 31 December 2009, who fulfilled Centers for Disease Control and Prevention criteria for influenza-like illness and developed severe outcomes from laboratory confirmed H1N1 infection. For each case, two controls presenting with influenza-like illness but without severe outcomes were included: one random control and one age matched control.
Main Outcome Measures. Severe outcomes included death or admission to intensive care for assisted ventilation, inotropic support, or both. Multivariable conditional logistic regression was used to compare cases and controls, with effect sizes measured as adjusted odds ratios.
Results. 151 (57%) of the 265 cases were male, the median age was 6 (interquartile range 2.3-10.0) years, and 27 (10%) died. Six factors were associated with severe outcomes in children presenting with influenza-like illness: history of chronic lung disease (odds ratio 10.3, 95% confidence interval 1.5 to 69.8), history of cerebral palsy/developmental delay (10.2, 2.0 to 51.4), signs of chest retractions (9.6, 3.2 to 29.0), signs of dehydration (8.8, 1.6 to 49.3), requirement for oxygen (5.8, 2.0 to 16.2), and tachycardia relative to age).
Conclusion. These independent risk factors may alert clinicians to children at risk of severe outcomes when presenting with influenza-like illness during future pandemics.
In June 2009 the World Health Organization declared the first global influenza pandemic in 41 years. From early in the pandemic, children—particularly those aged under 5 years—were considered a population at higher risk of morbidity and mortality from pandemic H1N1 (pH1N1) infection.
Several studies from around the world have included children and adults admitted to hospital or intensive care units with pH1N1 infection. However, these data vary in format and emphasis, making direct comparison between studies difficult. Furthermore, data on severe outcomes (including death) and risk factors for severe outcomes are limited. One large multi-country analysis identified that risk for severe outcomes was associated with eight pre-existing medical conditions; unfortunately, data for paediatric and adult patients were combined, making conclusions specific to children difficult to formulate.
During the pandemic, emergency departments and primary care facilities experienced large surges of children presenting with influenza-like illness. These surges corresponded to influxes of pH1N1 related admissions to intensive care units. To date, no reports have detailed which factors in children with influenza-like illness and pH1N1 infection at presentation to emergency departments are associated with a risk of progression to severe disease or death. Such information would be highly relevant for informing emergency department and primary care clinicians regarding risk stratification, resource allocation, and clinical disposition in future pandemics.
We did this study to identify historical and clinical findings at presentation to emergency departments associated with severe outcomes of pH1N1 infection in children presenting with influenza-like illness. To answer this question on a global scale, we studied children presenting to the emergency departments of hospitals associated with the Pediatric Emergency Research Networks (PERN). PERN comprises representative hospitals from the five major paediatric emergency medicine research networks located in Europe, the Middle East, North America, and Australasia. Together, the five research networks have access to data from more than three million paediatric emergency department presentations annually, from more than 100 hospitals, in four of the six WHO regions.
Abstract and Introduction
Abstract
Objective. To identify historical and clinical findings at emergency department presentation associated with severe H1N1 outcome in children presenting with influenza-like illness.
Design. Multicentre retrospective case-control study.
Setting. 79 emergency departments of hospitals associated with the Pediatric Emergency Research Networks in 12 countries.
Participants. 265 children (<16 years), presenting between 16 April and 31 December 2009, who fulfilled Centers for Disease Control and Prevention criteria for influenza-like illness and developed severe outcomes from laboratory confirmed H1N1 infection. For each case, two controls presenting with influenza-like illness but without severe outcomes were included: one random control and one age matched control.
Main Outcome Measures. Severe outcomes included death or admission to intensive care for assisted ventilation, inotropic support, or both. Multivariable conditional logistic regression was used to compare cases and controls, with effect sizes measured as adjusted odds ratios.
Results. 151 (57%) of the 265 cases were male, the median age was 6 (interquartile range 2.3-10.0) years, and 27 (10%) died. Six factors were associated with severe outcomes in children presenting with influenza-like illness: history of chronic lung disease (odds ratio 10.3, 95% confidence interval 1.5 to 69.8), history of cerebral palsy/developmental delay (10.2, 2.0 to 51.4), signs of chest retractions (9.6, 3.2 to 29.0), signs of dehydration (8.8, 1.6 to 49.3), requirement for oxygen (5.8, 2.0 to 16.2), and tachycardia relative to age).
Conclusion. These independent risk factors may alert clinicians to children at risk of severe outcomes when presenting with influenza-like illness during future pandemics.
Introduction
In June 2009 the World Health Organization declared the first global influenza pandemic in 41 years. From early in the pandemic, children—particularly those aged under 5 years—were considered a population at higher risk of morbidity and mortality from pandemic H1N1 (pH1N1) infection.
Several studies from around the world have included children and adults admitted to hospital or intensive care units with pH1N1 infection. However, these data vary in format and emphasis, making direct comparison between studies difficult. Furthermore, data on severe outcomes (including death) and risk factors for severe outcomes are limited. One large multi-country analysis identified that risk for severe outcomes was associated with eight pre-existing medical conditions; unfortunately, data for paediatric and adult patients were combined, making conclusions specific to children difficult to formulate.
During the pandemic, emergency departments and primary care facilities experienced large surges of children presenting with influenza-like illness. These surges corresponded to influxes of pH1N1 related admissions to intensive care units. To date, no reports have detailed which factors in children with influenza-like illness and pH1N1 infection at presentation to emergency departments are associated with a risk of progression to severe disease or death. Such information would be highly relevant for informing emergency department and primary care clinicians regarding risk stratification, resource allocation, and clinical disposition in future pandemics.
We did this study to identify historical and clinical findings at presentation to emergency departments associated with severe outcomes of pH1N1 infection in children presenting with influenza-like illness. To answer this question on a global scale, we studied children presenting to the emergency departments of hospitals associated with the Pediatric Emergency Research Networks (PERN). PERN comprises representative hospitals from the five major paediatric emergency medicine research networks located in Europe, the Middle East, North America, and Australasia. Together, the five research networks have access to data from more than three million paediatric emergency department presentations annually, from more than 100 hospitals, in four of the six WHO regions.