Prognostic Factors and Analytical Abnormalities in Patients Admitted With the Diagnosis of Influenza in a Third Level Hospital During the 2015–2016 Season

Abstract

IntroductionInfluenza is an acute respiratory illness due to influenza A or B viruses, which is associated with an increased morbidity and mortality in certain high-risk populations, like children, elderly patients and those with multiple comorbidities. MethodsWe conducted a cross-sectional retrospective analysis including all patients identified with the following ICD 10 codes: J10.0, J10.1, J10.8–11.0, J11.1, J11.8. 258 patients were included. ResultsThe most frequent strain was influenza A H1N1 (81.8%). We found alterations in blood count in 163 (63.2%) patients and they were more frequent in men. In the case of liver enzymes, we found alterations in 155 (60.1%) patients, being more frequent in men, smokers or former smokers and non-A cases. 22 patients were admitted to the ICU and 20 died during hospital stay. We performed a multivariable logistic regression analysis that showed an association between ICU admission and the presence of infiltrates in chest radiography (OR=4.1, IC 95% 1.55–10.87; P=0.004), previous antibiotic treatment (OR=5.84, IC 95% 1.32–25.69; P=0.020), anemia (OR=7.29, IC 95% 1.38–38.41; P=0.019) and no initial suspicion of influenza (OR=8.07, IC 95% 1.48–43.89; P=0.016). We also found an association between mortality and age (OR=1.04, IC 95% 1.01–1.09; P=0.026), the presence of infiltrates in chest radiography (OR=2.19, IC 95% 1.26–3.81; P=0.005) and no initial suspicion of influenza (OR=5.43, IC 95% 1.60–18.47; P=0.007). Finally, our analysis showed that the variables linked to a length of hospital-stay >5 days were concomitant antibiotic treatment during admission (OR=14.36, IC 95% 2.23–92.35; P=0.005) and liver enzymes alterations (OR=3.01, IC 95% 1.26–7.12; P=0.013).