By Ethan Covey
Nearly half of all deaths among patients who were hospitalized with influenza occurred after hospital discharge and within 30 days of discharge, and more than one-third of all patients hospitalized with influenza who died had “influenza” listed as a cause of death, according to a recently published report (Clin Infect Dis 2024 Nov 4. doi:10.1093/cid/ciae547 https://doi.org/10.1093/cid/ciae547).
“This suggests that the burden of all-cause mortality in patients hospitalized with influenza in the U.S. may be underestimated,” said Alissa O’Halloran, MSPH, an epidemiologist with the CDC National Center for Immunization and Respiratory Diseases.
“Causes of death in patients who died after discharge were more often recorded as being related to chronic underlying conditions like cardiovascular disease rather than acute infections,” Ms. O’Halloran said. “For these patients, this may indicate that chronic conditions play a larger role in contributing to all-cause mortality in nonhospitalized settings, but also raises questions about the longer-term impacts of acute influenza virus infection on control of preexisting medical conditions.”
The study focused on data from the Influenza Hospitalization Surveillance Network for the flu seasons of 2010-2011 through 2018-2019. A total of 121,390 cases of laboratory-confirmed influenza were identified. Among these, 5.5% of patients died, 76% of deaths were in patients 65 years of age and older, 71% were non-Hispanic white, and 34% had four or more underlying medical conditions. Of those patients who were hospitalized because of their influenza and died, 48% of deaths occurred after hospital discharge.
“Medical providers should be aware of the risk for mortality soon after discharge from an influenza-associated hospitalization, particularly among older adults and those with underlying medical conditions,” Ms. O’Halloran said. “Given the substantial burden of mortality within 30 days of discharge from a flu hospitalization, ensuring that patients have good follow-up care soon after discharge is particularly important, especially for older adults or those with underlying medical conditions that puts them at higher risk for complications.”
Ms. O’Halloran stressed the importance of annual influenza vaccination for all people 6 months of age and older. Adults 65 years of age and older are recommended to receive high-dose or adjuvanted influenza vaccine, she said. Antiviral treatment also is recommended as soon as possible for any patient with suspected or confirmed influenza who is hospitalized; has severe, complicated or progressive illness; or is at higher risk for flu complications.
“Earlier treatment initiation, ideally within 48 hours of symptom onset, provides greater clinical benefit compared with late initiation,” she said.
Ms. O’Halloran noted that in addition to post-discharge mortality, further studies would help to better understand the impact of an influenza-associated hospitalization on a patient’s need for rehospitalization or other downstream impacts on their health status and well-being.
“Given that most prior studies have largely focused on in-hospital deaths, we do feel that the medical community may not fully appreciate the true burden of influenza on post-hospitalization morbidity and mortality, particularly among older adults,” she said.
The sources reported no relevant financial disclosures.
