Hypersensibilités aux produits de contraste iodés : analyse en cluster

Abstract

Introduction Cluster analysis refers to a broad set of unsupervised learning techniques used to discover distinct subgroups or clusters within a set of data. This study aimed to distinguish different clinical characteristics among patients with suspicions of drug hypersensitivity reactions (DHRs) to iodinated radiocontrast media (iRCM) based on a cluster analysis. Methodes A retrospective study was performed using data extraction from the Drug Allergy and Hypersensitivity Database (DAHD) at the Allergy Unit, University Hospital of Montpellier, France. All referred patients with suspicions of iRCM DHRs between February 2001 and December 2019 either with confirmed positive skin tests (ST)s or negative STs were included in the analysis. Resultats A total of 1439 patients with suspicion of a DHR to iRCM who underwent a drug allergy work-up were analysed. Positive STs were displayed in 153 patients (10.6 %). The solution proposed by the automatic cluster analysis categorized the 1439 patients into five clusters, with a fair quality of clustering and an optimal ratio (2.3) of the cluster sizes. Cluster 1 contained almost only patients with a non-immediate reaction. Cluster 2 comprised virtually only patients with immediate reactions (IR), all with known culprit iRCM. These were the best defined clusters. Cluster 4 and 5 were virtually identical, with one exception, namely the clinical manifestation. Where they both comprised IRs, with multiple episodes of DHR, induced by unknown culprits, tested two decades after the index reaction, cluster 5 contained virtually only anaphylactic events whereas cluster 4 included various reactions, but no anaphylaxis. Confirmed allergies were more frequent in cluster 1 (16.9 %) and 2 (16.5 %). Conclusion Five clinical phenotypes which make sense clinically were determined by cluster analysis. From a pragmatic point of view, this new knowledge can be integrated in the drug allergy work-up reasoning : patients with well-defined recent reactions are allergic in up to 17 % of cases, but the frequency of allergy is leveled down by two or more in reactions tested more than a decade after their occurrence, despite the clinical manifestation which can resemble anaphylaxis.