Page 71 - ADULT-ONSET ASTHMA PREDICTORS OF CLINICAL COURSE AND SEVERITY

DIAGNOSTIC ACCURACY OF MINIMALLY INVASIVE MARKERS FOR DETECTION OF AIRWAY EOSINOPHILIA IN ASTHMA
INTRODUCTION
Historically, asthma control has been pursued by means of symptom and lung func on monitoring1. Although the currently available asthma medica ons are e ec ve in controlling the disease in most pa ents, a minority deteriorates despite maximal treatment. Non- eosinophilic asthma responds poorly to cor costeroid therapy, the current standard treatment for suppressing airway in amma on. Approximately half of the asthma c pa ents seem to be persistently non-eosinophilic2.
Bronchoalveolar lavage (BAL) and endobronchial biopsy (EBB) are the reference standards for iden fying the extent of eosinophilic airway in amma on, but these tests are invasive and expensive. Another op on is induced sputum, which has shown to be clinically useful in guiding asthma treatment3.
A Cochrane review showed that the frequency of asthma exacerba ons is signi cantly lower in pa ents in whom inhaled cor costeroids are tailored based on sputum eosinophila, compared to those in whom management is based on tradi onal methods of asthma monitoring3. Recent guidelines recommend guiding treatment in severe asthma by sputum eosinophil counts in addi on to clinical criteria in centers experienced in using this technique1;4. Sputum eosinophilia may also have prognos c value as a marker for persistent air ow limita on5, deteriora ng asthma over me6, and responsiveness to future therapies speci cally targe ng eosinophilic in amma on, such as Mepolizumab7.
Unfortunately, sputum induc on is me-consuming, requires experienced laboratory personnel, and many pa ents are unable to produce adequate samples. Several minimally invasive markers of eosinophilic airway in amma on, such as Frac on of exhaled Nitric Oxide (FeNO), blood eosinophils and serum perios n, may have poten al as a surrogate to replace sputum induc on, but their accuracy to dis nguish between pa ents with and without airway eosinophilia remains controversial.
We performed a systema c review and meta-analysis with the purpose of obtaining summary es mates of the diagnos c accuracy8 of markers for airway eosinophilia in asthma c pa ents.
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