Asthma Influences Treatment and Outcomes in Pediatric Critical Influenza

Children with and without pre-existing asthma experience health resource use and symptoms in post-discharge outcomes following influenza critical illness, according to study findings published in The Journal of Allergy and Clinical Immunology: In Practice.

Researchers conducted a multicenter, prospective, observational study that included 179 children aged 8 months to 17 years who were admitted to a pediatric intensive care or step-down unit for influenza or another respiratory pathogen between December 2019 and April 2020. Results were stratified by pre-existing asthma. Only patients with respiratory infection due to influenza confirmed with clinical and research testing were evaluated. Patients who presented more than 10 days following illness onset, had pre-existing respiratory failure, were pregnant, or did not have a respiratory specimen collected within 72 hours of hospitalization were excluded.

Primary exposure was defined as parental report of asthma or reactive airways disease- health care provider-diagnosis, or electronic health record documentation of asthma or reactive airways disease. The primary endpoint was respiratory-specific health-resource use post-discharge.

The researchers excluded 14 patients labeled as loss to follow-up who were subsequently not included in study findings, and they excluded 26 patients labeled as lost to follow-up who were included in study findings prior to 90-day follow-up.

Of the 165 children with influenza, 56 had pre-existing asthma (median age, 6.3 years; interquartile range [IQR], 3.0-10.6) of whom 41.1% were fully vaccinated against influenza. The remaining 66.1% (median age, 5.1 years; IQR, 2.4-9.0) did not have pre-existing asthma, and 39.4% were fully vaccinated against influenza.

Among patients with pre-existing asthma, 28.5% had Hispanic ethnicity and 28.5% had Black ethnicity. Among patients without pre-existing asthma, 14.6% had Hispanic ethnicity and 9.1% had Black ethnicity.

Intubation occurred in 26.7% of patients with asthma and in 31.1% of patients without pre-existing asthma.

Patients with asthma received pharmacologic asthma treatments in hospital (76.7%) compared with patients without pre-existing asthma who received pharmacologic asthma treatments in hospital (28.4%). They noted 3 patients died in hospital (1 with pre-existing asthma).

Among the 136 patients with 90-day follow-up, 4.3% of patients with pre-existing asthma had an emergency department or urgent care visit vs 6.6% of patients without pre-existing asthma. The researchers noted 8.6% of patients with pre-existing asthma were readmitted to the hospital vs 3.3% without pre-existing asthma.

Asthma symptoms were experienced post-discharge in 78.2% of patients with pre-existing asthma compared with 3.3% of patients without pre-existing asthma. The researchers noted 52% of patients with pre-existing asthma had a respiratory specialist visit compared with 20% without pre-existing asthma. A total of 10 patients without pre-existing asthma reported a new diagnosis of asthma.

Limitations of the study include the observational design, underpowered sample size, and possible misclassification of pre-existing asthma.

The study authors conclude, “[W]e identified respiratory health resource use and symptoms as important post-discharge outcomes for children with critical influenza in those with and without pre-existing asthma.” They wrote, “The post-discharge respiratory sequelae underscore the importance of pulmonary follow-up in children with pre-existing asthma — as well as those without pre-existing asthma — given that one in ten children in our cohort were newly diagnosed with asthma after discharge.”