Page 86 - ADULT-ONSET ASTHMA PREDICTORS OF CLINICAL COURSE AND SEVERITY

ADULT-ONSET ASTHMA – PREDICTORS OF CLINICAL COURSE AND SEVERITY
RESEARCH IN CONTEXT
SYSTEMATIC REVIEW
MEDLINE, Embase and PubMed were searched from incep on to August 2014 for studies evalua ng the diagnos c accuracy of minimally invasive markers against a reference standard of induced sputum, bronchoalvealar lavage and/or endobronchial biopsy in pa ents with (suspected) asthma. A detailed search strategy can be found in Appendix 1. Twenty-one studies were eligible. We also included 11 studies with unpublished diagnos c accuracy data. To put our research in context, we used the same search strategy to look for studies that inves gated a poten al clinical role of airway eosinophilia or the inves gated minimally invasive markers in asthma, especially focusing on systema c reviews and clinical guidelines that aim to include all relevant informa on on a speci c topic.
INTERPRETATIONS
There is evidence for a clinical role of monitoring airway eosinophilia in asthma. A Cochrane review demonstrated that the frequency of asthma exacerba ons can be signi cantly reduced when tailoring inhaled cor costeroids on sputum eosinophilia. Recent ERS/ATS and GINA guidelines recommend guiding treatment in severe asthma by sputum eosinophil counts in addi on to clinical criteria in centers experienced in using this technique, although they acknowledge that quality of evidence is “very low”. Since exis ng reference standards are invasive, expensive and/or o en not feasible, a minimally invasive marker would be clinically useful. FeNO is o en referred to as a surrogate for airway eosinophila in the medical literature, and an ATS guideline on the Interpreta on of FeNO for Clinical Applica ons strongly recommends speci c cuto s of FeNO to rule-in and rule-out eosinophilic in amma on. This systema c review found that the performance of FeNO, blood eosinophils, and total IgE in detec ng airway eosinophilia in asthma is limited. There are currently no single markers available with a large enough documented accuracy to replace induced sputum.
SUPPLEMENTARY MATERIAL
Appendix 1-10 can be viewed online at thelancet.com
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