Preparing international classification of diseases (ICD)-11: Model of allergic and hypersensitivity conditions

Abstract

Originally considered rare disorders, allergic and hypersensitivity conditions (A/H) are among the fastest-growing conditions worldwide and are becoming a major public health problem. Efforts to record the impact of A/H in a structured and systematic way have so far been hampered by the absence at a conceptual and operational level of definitions of these conditions, which in turn has impeded comprehensive public health measures and investment. One recognized reason is the difficulty of coding A/H under the World Health Organization (WHO) ICD system (International Classification of Diseases: ICD-10). Taking the ICD-11 revision as a key window of opportunity, a detailed academic and evidence-based action plan was put in place under the ALLERGY in ICD-11 initiative, with the aim of creating a more appropriate classification for allergic and hypersensitivity conditions in this new edition of ICD. This work consisted in strategic international actions acknowledged by the Joint Allergy Academies and the WHO ICD representatives. These efforts resulted in the creation of a new “Allergic and hypersensitivity conditions” section in the chapter on “Disorders of the Immune system”. We were also able to introduce changes in the WHO mortality coding rules to include anaphylaxis as an underlying cause of death in official death certificates. In recognition of the work done and with the aim of formalizing collaboration with the WHO Family on International Classifications (WHO-FIC), a WHO Collaborating Center (WHO CC) for the Scientific Classification of Allergic and Hypersensitivity Diseases was established in June 2018 at the University Hospital of Montpellier, with Luciana Kase Tanno being appointed to the 20-member Medical and Scientific Advisory Board to support the WHO ICD and other international classifications. ICD-11 was presented and fully endorsed during the last World Health Assembly (May 2019) and this new classification is currently being introduced worldwide, with full global implementation anticipated by 2022. The creation of a new classification of A/H disorders in ICD-11 may be considered a timely and much-needed milestone in the history of the allergy specialty. More reliable, accurate, comprehensive and comparable A/H epidemiological data will provide a far clearer global picture of these conditions and will underpin improved management of allergic disorders worldwide.