Evaluation of Hospitalized Patients with Community-Acquired Influenza-Like Illness During Two Influenza Seasons

Objective: Influenza is among the most important respiratory infections affecting all age groups and can lead to hospitalizations. We aimed to determine the frequency of influenza infections among acute admissions with influenza -like illness (ILI) and evaluate the demographic, clinical findings, and outcomes of patients with influenza. Methods: This prospective, active surveillance study was conducted in a university hospital between 2015 and 2017. Patients hospitalized for at least 24 hours in the selected units with community -acquired ILI were screened according to certain influenza -predicting ICD-10 codes. Nasopharyngeal and pharyngeal swab samples were taken from patients who were eligible for the study. Patients tested for influenza with real-time polymerase chain reaction. Univariate and multivariate analyses were performed for data. Results: Among 440 patients screened according to influenza -related ICD-10 codes, 112 were included. Influenza positivity was detected in 37 of the 112 patients. Clinical findings were similar between influenza positive and negative groups and also between influenza subtypes, excluding sore throat, which was more common in the H1N1 group. Alanine transaminase (ALT), aspartate transaminase (AST), and creatine kinase (CK) elevations were found to be significantly higher in the influenza -positive group. When influenza -positive patients with and without pneumonia were compared, the rate of vaccination in the same season was higher in patients without pneumonia than in patients with pneumonia (38.8% and 10.5%, respectively; p=0.04). Conclusion: Integrating molecular tests detecting both influenza and other respiratory viruses into influenza surveillance programs can increase the efficacy and quality of these programs. The elevation of AST, ALT, and CK in influenza cases can be considered in distinguishing influenza from other ILI cases. Vaccination in the same season can reduce the risk of pneumonia in influenza -positive patients.