Pediatric Influenza Antiviral Use Varies by Age and Geographic Region

Pediatric influenza antiviral agents are underused among pediatric patients and their use varies widely, especially geographically and by patient age, researchers reported in Pediatrics.

A cross-sectional study assessed trends in the dispensing and costs of antivirals among children and adolescents with influenza in the US, using data from the MarketScan Commercial Claims and Encounters Database.

Data were obtained for participants aged 0 to 18 years from July 1, 2010, to June 30, 2019. Antiviral exposures were identified based on outpatient pharmacy dispensing claims for oseltamivir, zanamivir, and baloxavir. The primary outcome was the rate of antiviral dispensing, which was the number of pharmacy claims for any influenza antiviral that was dispensed, divided by the total number of enrolled children.

A total of 1,416,764 unique instances in which antivirals were dispensed from 2010 to 2019 were included for analysis. Children who received antiviral agents had a median age of 9 years (interquartile range [IQR], 5-13), and antivirals were dispensed more frequently in boys and older children. Oseltamivir was the most commonly prescribed antiviral (>99%).

The overall antiviral dispensing rate was 20.6 per 1000 children per season (range, 4.35-48.6 per 1000 children per season), with the dispensing of antivirals generally increasing throughout the season. The overall dispensing rate per 1000 influenza diagnoses was 606 (range, 494-673 per influenza season).

Antiviral treatment in children diagnosed with influenza and prophylactic treatment rates varied by age, with children aged at least 12 years receiving more acute antiviral treatment and those aged 2 to 11 years receiving more prophylactic dispensing. The antiviral treatment dispensing rate for children under 2 years of age with an influenza diagnosis was 367 per 1000 influenza diagnoses. For those aged under 2 years with an influenza diagnosis, influenza antivirals were prophylactically dispensed for 233 per 1000 influenza diagnoses.

Geographic variation in dispensing rates was based on the most recent influenza season available (2018-2019), when a 3-fold variation in dispensing rates was observed, ranging from 25 per 1000 enrolled children living in the Pacific region to 78 per 1000 of those in the East South-Central region. Geographic dispensing rates varied according to season, with substantial differences between the highest and lowest regional rates, ranging from a 3.1-fold difference in 2018 to 2019 to a 21-fold difference in 2010 to 2011.

Total adjusted prescription costs were $208,458,979 (median adjusted cost, $138). Variation occurred in inflation-adjusted costs for individual prescriptions, with a range of $111 (IQR, 92-113) in the 2010 to 2011 season to $151 (IQR, 123-299) in the 2016 to 2017 influenza season. The highest costs occurred in the 2017 to 2018 season ($46,345,486), and the lowest costs were in the 2011 to 2012 season ($7,838,740).

Study limitations include the use of medication dispensing with an insurance pharmacy claim as a proxy for antiviral usage. Also, the researchers were unable to determine individual-level, laboratory-confirmed influenza infections or to identify children at high risk for influenza complications. Misclassification of some cases of prophylactic antiviral use may also have occurred.

“The rates of guideline-concordant treatment of young children at a high risk of influenza complications are low, and there is marked variation in influenza antiviral treatment by geographic region,” stated the investigators. “These findings suggest a target area for care improvement in the treatment of children with influenza.”

Disclosure: Some of the study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.

This article originally appeared on Pulmonology Advisor