Health care resource utilization was found to be greater in patients with asthma with elevated blood eosinophil counts, according to study results published in the Annals of Allergy, Asthma and Immunology.

Data on patients with a diagnosis of asthma were extracted between January 2007 and December 2014 from the Midwest component of a claims database, including national commercial insurance claims. In this database, patient encounters are tracked using longitudinal claims data, which includes pharmacy data (ie, all filled prescriptions) and medical claims for insured members.

In this study, investigators sought determine whether peripheral blood eosinophil elevations were associated with resource utilization and cost among patients with asthma in a real-world health care system, in an effort to provide actionable treatment pathways based on eosinophil counts.

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Eligible participants were ≥18 years of age, had ≥1 primary asthma diagnosis delivered in an inpatient setting or ≥2 separate instances of an asthma diagnosis recorded in an outpatient or an emergency department (ED) setting. The index date was the date of recorded asthma diagnosis. All participants had to have continuous enrollment for 24 months following the index date. The 12-month period after the index date was the assessment period, and the next 12 months, the follow-up period.

A total of 3687 individuals were enrolled in the study. In this cohort, 15% of the patients were classified as having uncontrolled asthma, based on the European Respiratory Society/American Thoracic Society guidelines, 14% were classified as having severe asthma according to the Global Initiative for Asthma (GINA) guidelines. In the 3 months preceding the follow-up period, 1152 patients underwent an eosinophil test. Among those patients, 56% and 29% had a blood eosinophil count ≥150 cells/µL and f ≥300 cells/µL, respectively.

At the ≥150-cells/µL blood eosinophil count threshold, the comparison group included 3043 individuals (n=508 without eosinophil count elevation; n=2535 without an eosinophil test).

During the follow-up period, a greater percentage of patients with vs without elevated eosinophil counts at the ≥150-cells/µL threshold were hospitalized (18% vs 12%, respectively; P =.0001), and had ED (32% vs 27%, respectively; P =.027) and outpatient (62% vs 54%, respectively; P <.0001) visits. In the subgroup of participants with controlled asthma, a greater percentage of patients with vs without elevated eosinophil counts had hospitalizations, and ED and outpatient visits.

At the ≥300 cells/µL blood eosinophil count threshold, the percentage of patients with vs without eosinophil elevations who had all-cause hospitalizations was greater in the entire cohort (19% vs 13%, respectively; P =.002) as well as in the subgroup of participants with controlled asthma (19% vs 12%, respectively; P =.004).

”All patients with asthma could benefit from frequent peripheral blood eosinophil count screening to potentially identify the subgroup that may benefit from a step-up in asthma therapy,” concluded the study authors.


Dotiwala Z, Casciano J, Davis JR, et al. Impact of clinically significant thresholds of eosinophil elevation on healthcare resource use in asthma [published online May 1, 2020]. Ann Allergy Asthma Immunol. doi: 10.1016/j.anai.2020.04.024