Study Examines Wide Range of Potential Influenza-Related Complications

A new study highlights a broadened scope of the burden of influenza-associated complications, indicating that health care providers should be aware of a wider range of potential complications that can occur in patients.^1,2   

In addition to pneumonia being a common respiratory complication of influenza, the virus can also exacerbate underlying chronic respiratory disease. Complications can even encompass nonrespiratory diagnoses that may lead to hospitalization, which are likely underrecognized.

The study, published in JAMA Network Open, examined influenza’s role in respiratory and nonrespiratory complications in hospitalized adult patients. Data used for the study included more than 76,000 adults hospitalized with laboratory-confirmed influenza between 2010 and 2018 in the United States.

The results showed that 94.9% of patients had a respiratory diagnosis and 46.5% had a nonrespiratory diagnosis, including 5.1% with only nonrespiratory diagnoses. Pneumonia (36.3%), sepsis (23.3%), and acute kidney injury (20.2%) were the most common acute diagnoses, according to the study.

Additionally, fewer patients with only nonrespiratory diagnoses (81%) received antiviral therapy for influenza compared with those with respiratory diagnoses (89%). The study authors noted that this finding suggests “possible missed opportunities to most effectively manage influenza infections in hospitalized patients.”

Patients with pneumonia, sepsis, and acute kidney injury had a high frequency of severe hospital outcomes, including intensive care unit admissions (26% to 33%) and in-hospital mortality (6% to 8%), according to the findings.

Additionally, among patients with at least 1 acute respiratory complication, 43% had an underlying respiratory medical condition, such as asthma or chronic obstructive pulmonary disease. There was also a significantly higher frequency of underlying medical conditions, including metabolic (52%), cardiovascular (51%), renal (33%), neurological (30%), immunosuppressive (19%), hepatic (7%), and hematologic (6%).

“The results suggest that a full appreciation of the spectrum of disease and the burden associated with influenza should consider the potential respiratory and nonrespiratory diagnoses,” the authors wrote in the study.

The findings underscore the importance of influenza vaccination, especially for individuals at high risk for serious complications, including those with underlying medical conditions.

References:

1. Chow EJ, Rolfes MA, O’Halloran A, et al. Respiratory and nonrespiratory diagnoses associated with influenza in hospitalized adults. JAMA Network Open. 2020. Doi: 10.1001/jamanetworkopen.2020.1323

2. New Study Expands Understanding of Influenza-associated Complications. CDC’s website. https://www.cdc.gov/flu/spotlights/2019-2020/study-flu-complications.html. Accessed March 26, 2020.