Predictors of Death in Patients with H1N1 Influenza: A Retrospective Analytical Study

Influenza A virus subtype H1N1, known as H1N1 influenza virus, could cause moderate to severe swine influenza in humans. H1N1 influenza is associated with high mortality rate. Effective symptom management could significantly reduce the mortality rate. This study aimed to determine the clinical manifestations, outcomes, and predictors of mortality in patients with H1N1 influenza, admitted to hospitals during January to September 2016.

This retrospective descriptive-analytical study was conducted during January to September 2016 in eight hospitals located in Razavi Khorasan province, northeastern Iran. The medical records of 65 patients were retrieved, and the necessary data were extracted from the records using a demographic questionnaire and a clinical manifestations checklist. The SPSS software Version 23.0 was used to analyze the data via the measures of descriptive statistics and the logistic regression analysis with odds ratio.

The most common clinical manifestations of H1N1 influenza were headache (70.8%), numbness in the extremities (63.1%), myalgia (60%), cough (58.5%), fever and shivering (53.8%), and nausea (53.8%). In total, 14 (21.53%) patients had died due to H1N1 influenza. The significant predictors of death were dyspnea (OR: 13.91, p: .032), myalgia (OR: 0.04. p: .010), and age (OR: 1.05, p: .024) so that dyspnea and myalgia were associated with 13.9 and 0.04 times higher odds of death, respectively. Moreover, each one year increase in age was associated with 5% increase in the odds of experiencing death.

In the case of H1N1 influenza epidemics, care services need to be allocated more to patients who have higher age and suffer from myalgia and dyspnea.