Refractory Asthma: Importance of Bronchoscopy to Identify Phenotypes and Direct Therapy

Background: The pathophysiology of refractory asthma is not well understood and thus treatment modalities are not targeted to specific phenotypes, but rather a broad based treatment approach is used. The objective of this study was to develop refractory asthma phenotypes based on bronchoscopic evaluation, and from this information, to develop specific, directed personalized therapy.

Methods: Fifty-eight difficult to treat (refractory) asthmatic patients were characterized by the use of fiberoptic bronchoscopy with visual scoring systems of the upper and lower airways as well as bronchoalveolar lavage, endobronchial biopsy and brush. Response to changes in therapy was evaluated by changes in the Asthma Control Test and pulmonary function.

Results: Five mutually exclusive phenotypes were formulated based on bronchoscopic evaluation: gastroesophageal reflux, subacute bacterial infection, tissue eosinophilia, combination, and nonspecific. Specific directed therapy yielded a significant improvement in the Asthma Control Test and pulmonary function for the entire group as well as for each defined subgroup except for the nonspecific group. Of interest, visual scoring of the supraglottic abnormalities identified 34/35 patients with gastroesophageal reflux and may give a better insight into asthmatic problems associated with chronic proximal reflux than standard testing.

Conclusions: Bronchoscopic evaluation of the upper and lower airways can provide important information regarding characterizing refractory asthma so as to better individualize therapeutic options and improve asthma control and lung function in these difficult to treat patients.