BACKGROUND: The lack of centralised data on severe asthma has resulted in a scarcity of information about the disease and its management. The development of a common data collection tool for the International Severe Asthma Registry (ISAR) will enable standardised data collection, subsequently enabling data interoperability.

OBJECTIVES: To create a standardised list of variables for the first international registry for severe asthma via expert consensus.

METHODS: A modified Delphi process was used to reach consensus on a minimum set of variables to capture in ISAR: the core variables. The Delphi panel brought together 27 international experts in the field of severe asthma research. The process consisted of three iterative rounds. In each round, all Delphi panel members were issued an electronic ISAR Delphi workbook to complete and return to the ISAR Delphi administrator. Workbooks and result summaries were anonymously distributed by the Delphi administrator to all panel members at subsequent rounds. Finalisation of the core variable list was facilitated by two face-to-face meetings.

RESULTS: Of the initial 747 selected variables, the Delphi panel reached a consensus on 95. The chosen variables will allow severe asthma to be assessed against patient demographics and medical history, patient-reported outcomes, diagnostic information and clinical characteristics. Physician-reported outcomes such as non-adherence and information about treatment and management strategies will also be recorded.

CONCLUSION: This is the first global attempt to generate an international severe asthma registry using a common set of core variables to ensure that data collected across all participating countries are standardised.