Response to inhaled corticosteroids (ICSs) in individuals with newly diagnosed asthma may be predicted by high blood and sputum eosinophil counts, according to a study published in the Annals of Allergy, Asthma and Immunology.
Recognizing that response to ICS treatment is varied, the investigators sought to evaluate the clinical factors and biomarkers associated with response to ICS in patients with newly diagnosed asthma. In this retrospective, observational study, the data of 150 patients naive to ICS and newly diagnosed with asthma, who consulted at the allergy clinic of the single tertiary hospital in South Korea between January 2014 and January 2019, were examined.
All patients initially received moderate-dose ICS for ≥1 year. Of the 150 participants, 99 patients had no acute exacerbation (stable asthma group) and 51 individuals presented with ≥1 acute exacerbation (unstable asthma group).
Blood eosinophil counts (635.7 ± 780.3 103/µL vs 373.4 ± 266.8 103/µL, respectively; P =.003) and sputum eosinophil counts (15.2 ± 23.9% vs 8.3 ± 15.4%, respectively; P =.051) were found to be higher in patients in the stable vs unstable asthma group. Sputum neutrophil counts were found to be lower in the stable vs unstable asthma group (42.9 ± 35.1% vs 61.3 vs 35.1%, respectively; P =.057).
The percentage of patients with low sputum eosinophil counts and high sputum neutrophil count was greater in the unstable vs stable group (≥3% and <65%, respectively), and the percentage of patients with high sputum eosinophil count and low sputum neutrophil count was greater in the stable vs unstable group. These differences, however, were not statistically significant. Moreover, no significant differences were reported with respect to fractional exhaled nitric oxide levels and total serum immunoglobulin E levels between the 2 arms.
“The sputum neutrophil count may be an effective predictor of response to ICS,” concluded the study authors. “However, further studies must be conducted to validate this result. Individuals who present with [acute exacerbation] despite ICS treatment are more likely to require high-dose ICS. Hence, other treatment strategies must be assessed and considered for these individuals.”
Rhyou H-I, Nam Y-H. Predictive factors of response to inhaled corticosteroids in newly diagnosed asthma: a real-world observational study [published online May 1, 2020]. Ann Allergy Asthma Immunol. doi: 10.1016/j.anai.2020.04.025