Demographic and Clinical Predictors of Mortality from Highly Pathogenic Avian Influenza A (H5N1) Virus Infection: CART Analysis of International Cases

Abstract

BackgroundHuman infections with highly pathogenic avian influenza (HPAI) A (H5N1) viruses have occurred in 15 countries, with high mortality to date. Determining risk factors for morbidity and mortality from HPAI H5N1 can inform preventive and therapeutic interventions.MethodsWe included all cases of human HPAI H5N1 reported in World Health Organization Global Alert and Response updates and those identified through a systematic search of multiple databases (PubMed, Scopus, and Google Scholar), including articles in all languages. We abstracted predefined clinical and demographic predictors and mortality and used bivariate logistic regression analyses to examine the relationship of each candidate predictor with mortality. We developed and pruned a decision tree using nonparametric Classification and Regression Tree methods to create risk strata for mortality.FindingsWe identified 617 human cases of HPAI H5N1 occurring between December 1997 and April 2013. The median age of subjects was 18 years (interquartile range 6–29 years) and 54% were female. HPAI H5N1 case-fatality proportion was 59%. The final decision tree for mortality included age, country, per capita government health expenditure, and delay from symptom onset to hospitalization, with an area under the receiver operator characteristic (ROC) curve of 0.81 (95% CI: 0.76–0.86).InterpretationA model defined by four clinical and demographic predictors successfully estimated the probability of mortality from HPAI H5N1 illness. These parameters highlight the importance of early diagnosis and treatment and may enable early, targeted pharmaceutical therapy and supportive care for symptomatic patients with HPAI H5N1 virus infection.

Emerging respiratory tract viral infections

“…Humanhuman transmission has been rare, as a metaanalysis has shown that only 1-2% of more than 12 500 study participants from 20 studies exposed to patients with A(H5N1) infection had sero-evidence for prior A(H5N1) infection [15]. Age, country, per capita government health expenditure and delay from symptom onset to hospitalization have been identified as the risk factors for mortality related to A(H5N1) infection, emphasizing the importance of early diagnosis, treatment and supportive care [17]. Age, country, per capita government health expenditure and delay from symptom onset to hospitalization have been identified as the risk factors for mortality related to A(H5N1) infection, emphasizing the importance of early diagnosis, treatment and supportive care [17].…”

Epidemiological parameter changes of global Avian Influenza H5N1 over two decades, from 1997 to 2017

“…However, the increased numbers of human cases in Egypt are of major concern because of the continued potential pandemic threat from H5N1. However, the prevalence of H5N1 were high in Egypt compare with other country like Indonesia, Vietnam, China, Cambodia and Thailand but mortality was lower in Egypt, it might related to earlier hospital admission, earlier identification and early treatment with Oseltamivir, less severe clinical disease, and less virulent virus clade, [21,24,25]. Mortality were more in first decade than second decade even so cases in second decade was more than first decade, This might related to public health awareness, earlier identification and use of antiviral drug oseltamivir.…”

Development of Disease‐specific, Context‐specific Surveillance Models: Avian Influenza (H5N1)‐Related Risks and Behaviours in African Countries

“…Unless humans are exposed to or consume infected poultry, H5N1 is not viewed as zoonosis (Fournié et al, 2013;Patel et al, 2014;Van Kerkhove et al, 2011). However, zoonotic dissemination may occur if bird-mediated (viral-human) contacts promote the full adaptation of the virus to humans (Van Kerkhove et al, 2011).…”