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Professor Helen Reddel
Blood eosinophils have less of a role in predicting exacerbations or guiding treatment in mild asthma than in severe asthma, according to an analysis from the multinational Novel START study.
The study comprised 675 adults with mild asthma, from 16 centres across four countries including Australia, who were using only a SABA such as salbutamol in the previous three months. They were randomised to either as-needed salbutamol, maintenance budesonide plus as-needed salbutamol or as-needed low-dose budesonide-formoterol.
Blood eosinophils, FeNO or a composite of both measures were investigated for their utility in predicting outcomes and response to treatment over 12 months.
The study found patients with higher baseline blood eosinophils (≥0·15 ×109/L) were almost three times as likely to have ever been hospitalised with an asthma exacerbation than those with lower blood eosinophils.
In patients assigned to as-needed salbutamol, exacerbations and severe exacerbations during the 12-month study increased progressively with increasing baseline blood eosinophil count.
The study also found maintenance budesonide was significantly more effective than as-needed salbutamol in patients with blood eosinophil counts of ≥0·3×109/L but no more effective than salbutamol in patients with blood eosinophils <0·15 ×109/L.
However, the benefits of as needed budesonide-formoterol compared with as-needed salbutamol for exacerbations and severe exacerbations were not predicted by the baseline blood eosinophils.
Elevated FeNO was not a prognostic biomarker for asthma exacerbations in any treatment group and did not predict response to treatment.
Co-investigator of the study Professor Helen Reddel, from the University of Sydney’s Woolcock Institute of Medical Research, told the limbic the most important finding was that patients with mild asthma didn’t need inflammatory phenotyping at baseline before being considered for treatment with as-needed budesonide-formoterol.