Methods
We conducted a retrospective observational monocentric study at the Allergy Department of the University Hospital of Montpellier, France. We included all patients – adults and children – who underwent a positive oral food challenge (OFC) for an IgE mediated food allergy, between January 2018 and December 2022. OFCs were performed following PRACTALL recommendations12.
The study was approved by the Institutional Review Board of Montpellier (IRB-MTP_2022_09_202201201).
Patients’ characteristics and information were extracted from the Food Allergy and Hypersensitivity Database® (FAHD). In case of missing data, a manual extraction was performed from the patient’s electronic and/or paper medical records. For each patient, the following data were collected: age, sex, clinical manifestations experienced during the reported clinical history, symptoms presented during the OFC, severity of the reaction according to different classifications and administered treatment.
We manually reclassified the severity of all reactions according to 5 classifications of food allergy-related anaphylaxis, published in the literature (ICD-11; CoFAR; Sampson; Muraro; Blazowski)7-11. We chose to use the ICD-11 classification7 as the reference one. Two independent allergists classified the severity of each reaction. Any disagreement between the two allergists was resolved through discussion with a third specialist to reach a final consensus.
The primary objective of the study was to evaluate the grading of a reaction considering the different classifications. Secondary objectives included the assessment of symptoms presented by patients during a positive OFC, compared with those reported in the patients’ initial clinical history, and the evaluation of the appropriateness of adrenaline injection, according to the severity of the symptoms and based on the guidelines of the European Academy of Allergy and Clinical Immunology (EAACI)13.
Qualitative variables were evaluated as frequencies and percentages, and the quantitative variables were evaluated as median and interquartile range. Spearman’s correlation coefficient was used to examine the correlation between the different classifications, and the gold standard (ICD-11 classification). ROC (Receiver Operating Characteristic) curves were plotted, with sensitivity, specificity, area under the curve (AUC), and corresponding optimal thresholds used to evaluate the diagnostic performance of each classification. AUCs were compared by the DeLong test. All analyses were performed using SAS version 9.4 (SAS Institute Inc, Cary, NC, USA).