Improving Severity Scoring of Food-Induced Allergic Reactions: A Global “Best-Worst Scaling” Exercise

Abstract

Background There is no current consensus on assigning severity to food-induced allergic reactions, for example, to assess the efficacy of allergen immunotherapy. Existing severity scores lack the capability to discriminate between non-anaphylaxis reactions of different severities. Attempts are ongoing to develop a more discriminatory score, which should ideally be data-driven and validated in multiple cohorts. Objective To undertake an exercise using best-worst scaling (BWS) to define a potential gold standard against which severity scoring of food-induced allergic reactions can be refined. Methods We undertook a global survey to better understand how health care professionals rate the severity of food-induced allergic reactions, using BWS methodology. Respondents were given a number of patient case vignettes describing real-world allergic reactions and asked to select the pair that, in their opinion, reflected the maximum difference in severity. Responses were then modeled and a preference score (representing severity) determined for each scenario. Scenarios were also scored using existing published scoring systems and the scores compared with the BWS score using Spearman r correlation and Cohen kappa. Given the differences in definitions of anaphylaxis globally, we also evaluated differences in BWS ranking depending on the geographical location of respondents. Results We received 334 complete responses, 183 (55%) from Europe and 65 (20%) from North America. Perception of severity of some reactions appeared to be affected by geographical location. The comparison of BWS ranking with current grading systems identified significant issues that varied from one grading system to another, such as prominence to some symptoms (eg, vomiting) that skew grading when using scoring systems not designed for food allergy. In general, current scoring systems poorly discriminate against more mild symptoms and often overestimate their severity. Conclusions These data provide a methodology free of user scale bias to help define a potential, consensus-driven gold standard that can be used to guide and validate the development of improved grading systems to score food-induced allergic symptoms and highlight areas for education where there is the potential to miscategorize severity.

Development and validation of the food allergy severity score

“…The responses to the MaxDiff survey were modeled and a “preference” score (representing severity) determined for each scenario 50 . These scores were compared to nFASS using Spearman's R correlation.…”

“…The survey was administered by an independent market Research company (ResearchNow, UK), with potential respondents contacted through the EAACI, Spanish Society of Allergy and Clinical Immunology (SEAIC), British Society for Allergy & Clinical Immunology (BSACI), and World Allergy Organization (WAO). Responses were voluntary, anonymous, and confidential (detailed information in Stafford et al 50 ).…”

“…and World Allergy Organization (WAO). Responses were voluntary, anonymous and confidential (detailed information in Stafford et al 50 ).…”

Grading the severity of anaphylaxis

“…To address this gap, we recently reported the results from a global consensus exercise to develop such a reference which could then be used by other groups to facilitate the development of a data-driven severity score [45 ▪▪ ]. Using best-worst scaling (BWS) methodology, we defined a severity ranking on the basis of 334 allergy healthcare professionals who participated from around the world.…”

Peanut Can Be Used as a Reference Allergen for Hazard Characterization in Food Allergen Risk Management: A Rapid Evidence Assessment and Meta-Analysis

“…However, the assignment of severity for food-induced allergic reactions is inconsistent in the literature, and each method has its limitations. 23 , 24 There is no universally accepted system for scoring the severity of food-allergic reactions. However, most food-allergic consumers and clinicians would consider reactions involving airway/breathing and/or cardiovascular compromise as severe, and there is an international consensus that such symptoms constitute “anaphylaxis” (despite there being multiple definitions for anaphylaxis in the literature).…”