Impact of influenza related hospitalization in Spain: characteristics and risk factor of mortality during five influenza seasons (2016 to 2021)

• DOI: 10.3389/fpubh.2024.1360372
• Publication Date: 2024-04-02T04:43:50Z
• Authors: José-Manuel Ramos...; Héctor Pinargote-...; Pilar González-de...; José Sánchez-Payá; Sergio Reus; Juan-Carlos Rodrí...; Esperanza Merino
• Keywords: Case fatality rate; Pandemic

Background Estimating the global influenza burden in terms of hospitalization and death is important for optimizing prevention policies. Identifying risk factors mortality allows design strategies tailored to groups at highest risk. This study aims (a) describe clinical characteristics hospitalizations with a diagnosis over five flu seasons (2016–2017 2020–2021), (b) assess associated morbidity (hospitalization rates ICU admissions rate), cost different age (c) analyze mortality. Methods retrospective included all hospital Spain seasons. Data were extracted from Spanish National Surveillance System Hospital 1 July 2016 30 June 2021. We identified cases coded as having primary or secondary (International Classification Diseases, 10th revision, J09-J11). The rate was calculated relative general population. Independent predictors using multivariable logistic regression. Results Over seasons, there 127,160 influenza. mean varied 5/100,000 2020–2021 (COVID-19 pandemic) 92.9/100,000 2017–2018. proportion admission 7.4% people aged 40–59 years (13.9%). case fatality 5.8% overall 9.4% those 80 older. Median length stay 5 days (and 6 oldest group). In analysis, independent male sex (odds ratio [OR] 1.14, 95% confidence interval [95% CI] 1.08–1.20), (<5 years: OR 1; 5–19 2.02, 95%CI 1.17–3.49; 20–39 4.11, CI 2.67–6.32; 8.15, 5.60–11.87; 60–79 15.10, 10.44–21.84; ≥80 33.41, 23.10–48.34), neurological disorder (OR 1.97, 1.83–2.11), heart failure 1.85, 1.74–1.96), chronic kidney disease 1.33, 1.25–1.41), liver 2.95, 2.68–3.27), cancer 1.48–2.24), coinfection SARS-CoV2 3.17, 2.34–4.28), pneumonia 1.76, 1.66–1.86) intensive care 7.81, 7.31–8.36). Conclusion Influenza entails major public health burden. People 60—and especially 80—show longest stays. Age also most significant factor mortality, along certain comorbidities.