Blood eosinophils can guide ICS therapy in primary care COPD patients

Blood eosinophil count could be used in primary care to guide decision-making on the initiation of inhaled corticosteroids (ICS) in COPD patients, a UK study has concluded.

An Oxford University research team sought to determine whether existing blood eosinophil counts can predict the likely benefit from starting ICS treatment compared to bronchodilator therapy.

For the real-world study, published in ERJ open research, the team used the UK’s Clinical Practice Research Datalink Participants to gather data on 9,475 eligible patients aged 40 years or over with COPD, who were ICS treatment-naïve and starting a new inhaled maintenance medication.

The trial’s primary outcome was time to first exacerbation in ICS and non-ICS groups, stratified by blood eosinophils where a high level was determined as ≥150 cells µL−1 and low <150 cells µL−1.

The results showed that exacerbation risk was higher in patients prescribed ICS than those prescribed non-ICS treatment, but that the risk was lower in those with high eosinophils (HR 1.04) than in those with low eosinophils (HR 1.19).

“This translated as a 15% lower absolute risk of subsequent exacerbations in patients with higher baseline eosinophil counts who were prescribed an ICS treatment, compared with patients with lower eosinophils who were prescribed ICS,” said the researchers, led by Dr Helen Ashdown of Oxford University’s Nuffield Dept of Primary Care Sciences.

A secondary analysis of data showed that risk of pneumonia hospitalisation with ICS was greatest in COPD patients with low eosinophils (HR 1.26).

Also, the researchers determined that results were not impacted by using a mean of eosinophil counts rather than a patient’s most recent values, or when levels recorded close to an acute illness were included.

On the back of these findings, they concluded that “in a primary care population, the most recent blood eosinophil count could be used to guide initiation of ICS in COPD patients,” and suggested that “ICS should be considered in those with higher eosinophils and avoided in those with lower eosinophils (<150 cells µL−1).”

The authors also emphasised “an urgent need to improve clarity around when ICS should be prescribed” as their study showed that, contrary to both national and international guidelines, almost one in five patients were started on ICS monotherapy for COPD, as shown in other real-life database studies.

“Appropriate use of inhaled corticosteroids is key in COPD as problems can arise with both over- and under-use,” Respiratory Consultant John Hurst, Professor of Respiratory Medicine, UCL Respiratory, University College London, told the limbic.

“Blood eosinophil results provide one approach to this, complementary to consideration of clinical factors, and as recommended in national and international guidelines”.

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