Antiviral treatment increases among US patients
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Data from the Influenza Hospitalization Surveillance Network showed that antiviral treatment increased among U.S. patients hospitalized with influenza during the 2010-2011 to 2014-2015 seasons.
However, researchers estimated that just over half of these patients received treatment on the first day of hospital admission despite the CDC’s recommendation to initiate early therapy in all patients with suspected or confirmed influenza.
“Early antiviral treatment among hospitalized patients is associated with reduced mortality in adults and shortened length of stay in children and older adults,” Infectious Disease News Editorial Board member William Schaffner, MD, medical director of the National Foundation for Infectious Diseases and professor of preventive medicine at Vanderbilt University School of Medicine, and colleagues wrote in Clinical Infectious Diseases. “The earlier treatment is initiated in the patient’s illness, the better the clinical outcomes.”
Before the A(H1N1)pdm09 pandemic, the percentage of hospitalized patients receiving antivirals ranged from 37% to 57%. Although treatment increased to approximately 80% during the pandemic, there was a significant decline during the 2010-2011 season. When the CDC detected A(H3N2) viruses in 2014-2015, the agency issued an advisory underscoring the importance of prompt therapy.
To determine the patterns of antiviral use in recent years, Schaffner and colleagues analyzed data from 267 acute care hospitals participating in the national Influenza Hospitalization Surveillance Network during the 2010-2011 to 2014-2015 influenza seasons. The analysis included 43,708 patients with laboratory-confirmed influenza, 84% of whom received antiviral treatment — primarily Tamiflu (oseltamivir, Roche; 99%).
According to the data, adults and patients with high-risk conditions were more likely to receive treatment than children (84% vs. 72%) and patients without high-risk conditions (86% vs. 77%). The percentage of all patients who received antivirals significantly increased from 72% during the 2010-2011 season to 89% during the 2014-2015 season (P < .001). The greatest increase was among children aged younger than 1 year (51% to 82%). The only statistically significant declines occurred among children aged 2 to 4 years during the 2010-2011 to 2011-2012 seasons (19% decrease) and 2013-2014 to 2014-2015 seasons (8% decrease; P = .03).
Despite these gains in treatment, only one-third of patients with available information were admitted to the hospital within 2 days of symptom onset when the clinical benefit of antiviral treatment is greatest, according to the researchers. Moreover, only 2% of patients received antivirals prior to hospitalization.
Improving antiviral use and sensitive, point-of-care influenza diagnostic tests in the outpatient setting — where many patients are seen earlier in their illness — may help increase timely therapy, Emily Toth Martin, MPH, PhD, of the department of epidemiology at the University of Michigan School of Public Health, wrote in a related editorial. She added that additional studies are needed to investigate optimal use of antivirals in patients with severe illness who are hospitalized outside of the 48-hour window.
“Now that antiviral treatment is approved, recommended, and the standard of care in the United States, further improvements in testing and empiric protocols will have to be made through large observational studies,” Martin wrote. “These studies are needed to refine treatment recommendations to align with the scenarios encountered in hospitalized cases of severe illness, where patients are often admitted later in their illness and may have complicating comorbidities.” – by Stephanie Viguers
Disclosures: Schaffner and the other researchers report no relevant financial disclosures. Martin reports receiving research funding from Merck and the Multiparty Group for Advice on Science through a grant from Roche Pharmaceuticals.