Defining a Severe Asthma Super-Responder: Findings from a Delphi Process

Background: Clinicians are increasingly recognizing severe asthma patients in whom biologics and other add-on therapies lead to dramatic improvement. Currently, there is no agreed-upon super-responder (SR) definition. Objective: To survey severe asthma experts using a modified Delphi process, to develop an international consensus-based definition of a severe asthma SR. Methods: The Delphi panel was composed of 81 participants (94% specialist pulmonologists or allergists) from 24 countries and consisted of three iterative online voting rounds. Consensus on individual items, whether acceptance or rejection, required at least 70% agreement by panel members. Results: Consensus was achieved that the SR definition should be based on improvement across three or more domains assessed over 12 months. Major SR criteria included exacerbation elimination, a large improvement in asthma control (two or more times the minimal clinically important difference), and cessation of maintenance of oral steroids (or weaning to adrenal insufficiency). Minor SR criteria were composed of a 75% exacerbation reduction, having well-controlled asthma, and 500 mL or greater improvement in FEV₁. The SR definition requires improvement in at least two major criteria. In the future, the SR definition should be expanded to incorporate quality of life measures, although current tools can be difficult to implement in a clinical setting and further research is needed. Conclusions: This international consensus-based definition of severe asthma SRs is an important prerequisite for better understanding SR prevalence, predictive factors, and the mechanisms involved. Further research is needed to understand the patient's perspective and to measure quality of life more precisely in SRs.