Simple Blood Count May Help Predict Flare-Up Risk in Asthma

TOPLINE:

Higher baseline counts of blood eosinophils (EOS) were associated with an increased risk for exacerbations in patients with asthma over 1 year, and higher baseline levels of fractional exhaled nitric oxide (FeNO) were linked to increased odds of exacerbations treated with only oral corticosteroids (OCS) in asthma and asthma plus chronic obstructive pulmonary disease (COPD) but linked to a decreased risk for all exacerbations in COPD.

METHODOLOGY:

• Researchers analyzed data from the multinational NOVELTY study to assess whether blood EOS counts and FeNO levels, alone and together, predict the risk for future exacerbations in patients with asthma, COPD, or both.
• Overall, 4319 patients were included in the EOS analysis (2138 with asthma, 1541 with COPD, and 640 with asthma plus COPD), and 7770 patients were included in the FeNO analysis (4166 with asthma, 2588 with COPD, and 1016 with asthma plus COPD).
• Baseline data included demographics, treatments, exacerbations, and lung function (spirometry and FeNO levels).
• Outcomes were assessed over the first year of follow‑up, and patients received usual care from their treating physicians.
• Exacerbation subtypes were categorized as all exacerbations, exacerbations treated with only antibiotics, and exacerbations treated with only OCS.

TAKEAWAY:

• Higher EOS counts at baseline were associated with an increased risk for all exacerbations in asthma (incidence rate ratio [IRR], 1.09; P = .033), meaning each doubling of the count corresponded to a 9% higher exacerbation rate; a similar trend of higher risk was seen in COPD that did not reach statistical significance.
• Higher FeNO levels at baseline were associated with a lower risk for all exacerbations in COPD (IRR, 0.91; P = .025). In asthma, FeNO levels showed no association with an overall risk for exacerbations; in asthma plus COPD, neither biomarker predicted the overall risk.
• In asthma, higher FeNO levels at baseline were linked to increased odds of exacerbations treated with only OCS (odds ratio [OR], 1.16) but decreased odds of exacerbations treated with only antibiotics (OR, 0.75); in asthma plus COPD, higher FeNO levels were also linked to increased odds of exacerbations treated with only OCS (OR, 1.55; P < .05 for all).
• In an analysis including both biomarkers, higher EOS counts at baseline independently predicted all exacerbations in asthma; however, both higher EOS counts and lower FeNO levels were independently associated with a higher risk for all exacerbations in COPD (P < .05 for all).

IN PRACTICE:

“[The study] finding is of importance for future studies and daily clinical practice as it indicates that assessment of exacerbation subtype might improve personalized treatment management,” the authors wrote.

SOURCE:

This study was led by Susan Muiser, University Medical Centre Groningen, Groningen, Netherlands. It was published online on April 21, 2026, in Thorax.

LIMITATIONS:

Diagnoses were assigned by treating physicians without standardized diagnostic criteria. Physicians had access to type 2 inflammation biomarker results, which may have influenced treatment decisions. Exacerbation subtypes were categorized using medical records and patient-reported information, introducing a potential recall bias.

DISCLOSURES:

The NOVELTY study was funded by AstraZeneca. Four authors reported being employees of AstraZeneca, with 2 of them also being shareholders. Several authors disclosed receiving travel grants, research grants, consulting fees, honoraria, and support to attend meetings; serving on advisory boards; and holding stock or stock options with multiple pharmaceutical companies and organizations, including AstraZeneca and WebMD Global.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.

A version of this article first appeared on Medscape.com.