Suboptimal Use of Antivirals Observed in Children Hospitalized for Influenza

Natasha B. Halasa, MD

Although antiviral treatment for influenza has been shown to reduce complications and mortality, particularly in children, there are variations in prescribing patterns, which may be linked to concerns about effectiveness or previous reporting biases.

Accordingly, a team of investigators, led by Natasha B. Halasa, MD, MPH, Craig Weaver Professor of Pediatrics, Pediatric Infectious Diseases, observed approximately 50% of children with laboratory-confirmed influenza were treated with antivirals, despite recommendations of antiviral treatment for hospitalized patients with confirmed or suspected influenza without the need for testing.

What were the methods?

Individuals eligible for enrollment were children <18 years old diagnosed with acute respiratory illness (ARI) who were enrolled in active surveillance at pediatric medical centers in 7 cities between November 2015 - June 2016.

Investigators defined influenza season as the period between the dates of the first through last influenza positive case for each specific site, based on research laboratory testing. Both nucleic acid amplification tests (NAATs) and rapid influenza diagnostic testing (RIDT) were used for clinical laboratory testing.

Then, influenza antiviral use was defined as an in-hospital receipt of a neuraminidase inhibitor (oseltamivir or zanamivir) or adamantane (amantadine or rimantadine) that was documented by chart review.

They noted receipt of influenza vaccine was determined by parental report of receiving influenza vaccination for children who were 6 months or older.

Investigators used generalized linear mixed-effects models in order to separately evaluate factors associated with influenza testing and antiviral treatment.

What were the findings?

Out of the 3926 enrolled children hospitalized with ARI or febrile illness between July 2015 - June 2016, only 2299 (58%) met eligibility criteria for the analysis. These children had a mean age of 2.8 years, with 58% of children male and 44% with ≥1 underlying medical condition.

Within that population, 1183 children (51%) were clinically tested for influenza, made up of 24% RIDT, 71% NAATs, and 6% both. Investigators observed factors with significant positive association with testing included neuromuscular disease (aOR = 5.35, 95% CI, 3.58 - 8.01), congenital heart disease (aOR = 2.52, 95% CI, 1.59 - 3.99), and immunocompromised status (aOR = 2.88, 95% CI, 1.66 - 5.01).

Moreover, factors negatively associated with testing included age (aOR = 0.93, 95% CI, 0.91–0.96), private versus public insurance (aOR = 0.78, 95% CI, 0.63 – 0.98) and chronic lung disease (aOR = 0.64, 95% CI, 0.51 – 0.81).

From the tested population, 117 children (10%) were found to be influenza positive. Data show clinicians provided antiviral treatment for 61 of 117 (52%) patients with a positive influenza test versus 66 of 1066 (6%) with a negative or unknown test result.

They noted that all treated patients received oseltamivir. The factors positively associated with antiviral treatment included neuromuscular disease (aOR = 1.86, 95% CI, 1.04 - 3.31) and immunocompromised state (aOR = 2.63, 95% CI, 1.38 - 4.99). Then, factors with negative associations included duration of illness (aOR = 0.92, 95% CI, 0.84 - 0.99) and chronic lung disease (aOR = 0.60, 95% CI, 0.38 - 0.95).

Takeaways

“Further studies may provide a better understanding of barriers to antiviral treatment among hospitalized children and promote increased use of antivirals for hospitalized children with suspected or confirmed influenza infection,” investigators wrote.

The study, “Influenza clinical testing and oseltamivir treatment in hospitalized children with acute respiratory illness, 2015–2016,” was published in Influenza and Other Respiratory Viruses.