A study published in Lancet Infectious Diseases reveals that the long-term risk of death and health problems associated with hospitalization related to coronavirus disease 2019 (COVID-19) is higher than that associated with hospitalization related to seasonal influenza.
Study: Long-term outcomes after hospitalization for COVID-19 versus seasonal influenza: a cohort study. Image credit: Andrii Vodolazhskyi / Shutterstock
Background
Like severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of the most recent COVID-19 pandemic, influenza viruses are enveloped RNA viruses that cause mild to severe respiratory infections. Both COVID-19 and influenza are associated with a higher risk of adverse health outcomes and mortality.
Previous studies comparing health outcomes between hospitalized patients with COVID-19 and patients with influenza have shown that infection with SARS-CoV-2 is associated with a higher risk of death and long-term health problems than seasonal influenza infection up to six months after the infection.
In this study, researchers examined both acute and long-term risks of death, health care utilization, and a comprehensive set of 94 health outcomes over an 18-month period in patients who were admitted to hospitals due to COVID-19 or seasonal influenza.
I study design
The study population included 81,280 patients with COVID-19 admitted to hospital between 2020 and 2022 and 10,985 patients with seasonal influenza hospitalized between 2015 and 2019. Patient data were obtained from the health databases of US Department of Veterans Affairs. Patients were followed for 18 months.
Parameters assessed in the study included acute and long-term risks and burdens of death, a comprehensive set of 94 health outcomes, ten organ systems, overall burden for all organ systems, hospital readmission, and intensive care unit (ICU) admission. Additionally, disability-adjusted life years (DALYs) per 100 people were estimated using appropriate statistical methods. Risks were assessed at 30 days, 180 days, 360 days, and 540 days after hospital admission.
Important observations
The study found a higher absolute death rate among hospitalized patients with COVID-19 than hospitalized patients with seasonal influenza at each time point tested. Specifically, COVID-19 was associated with an increased mortality rate of 8.62 per 100 people compared to influenza infection at day 540 after hospitalization.
Over the entire 540-day follow-up period, patients with COVID-19 showed a significantly increased risk of 64 of 94 health outcomes examined, including cardiovascular, coagulation and hematologic, fatigue, gastrointestinal, renal, mental health, metabolic, musculoskeletal , neurological, and pulmonary outcomes.
In contrast, patients with influenza infection showed an increased risk of six health outcomes, including chest pain, increased heart rate, type 1 diabetes, and three of four pulmonary outcomes (cough, hypoxemia, and dyspnea).
Considering health failures in all organs and systems, COVID-19 was associated with an excess rate of 78.7 per 100 people compared to influenza infection over the entire follow-up period. Additionally, COVID-19 was associated with a higher disability-adjusted life expectancy of 45.03 per 100 people compared to influenza infection.
Considering acute and long-term health outcomes, more than 50% of the adverse conditions associated with COVID-19 and influenza in all organs and systems examined, except the gastrointestinal system, occurred in the post-acute phase of infection. However, patients with COVID-19 showed relatively higher adverse outcomes in all organs except the pulmonary system in both the acute and post-acute phases of infection.
Compared to patients with influenza, patients with COVID-19 showed a higher risk of hospital readmission and ICU admission at all time points tested.
During the pre-Delta, Delta, and Omicron waves, hospitalization associated with COVID-19 was associated with higher risks of mortality, health problems in all organs except the pulmonary system, hospital readmission, and ICU admission in compared with influenza-related hospitalization. In all three pandemic waves, disease burden was higher in the post-acute phase than in the acute phase.
The risks of mortality and health problems due to COVID-19 remain higher than the risks associated with influenza, regardless of patients’ COVID-19 status and influenza vaccination.
Significance of the study
The study found that hospitalized patients with COVID-19 had a higher long-term risk of mortality, health problems, and health care utilization than hospitalized patients with influenza. Compared to influenza, COVID-19 is associated with a higher risk of health failures in almost all organs except the pulmonary system. In addition, hospitalization for COVID-19 was associated with higher disability-adjusted life years compared to hospitalization for influenza.
As mentioned by the scientists, the long-term health outcomes of patients with influenza or SARS-CoV-2 infection should be carefully monitored to prevent health complications and reduce the risk of mortality.
