Introduction

Anaphylaxis is a severe, potentially fatal, systemic allergic reaction that occurs suddenly after contact with an allergy-causing substance[1], and it can lead to serious consequences if there exists delayed diagnosis and inappropriate treatments, drugs are generally considered to be the main cause of anaphylaxis[2]. Although anaphylaxis is a rare adverse drug reaction(ADR), drug induced anaphylaxis remains the leading cause of allergic death in adults [3; 4]. In addition, with the introduction of new medications such as biologics, small molecule drugs, and new chemotherapeutic drugs, the incidence of hospitalization caused by drug induced anaphylaxis continues to increase [5; 6]. During the past decade, there has been an advanced understanding of the diagnosis, pathogenesis, and treatment management of anaphylaxis [7; 8], but significant data and knowledge gaps remain in key clinical care and research domains, such as population science, validated clinical or biomarker-based models that predict disease outcome, acute management, etc. [7; 9], especially in China[10]. There were few active surveillance studies and epidemiological data on anaphylaxis in China, and studies showed gaps in the initial treatment of anaphylaxis between China and international guidelines[11].
China Hospital Pharmacovigilance System (CHPS) was developed and popularized by the China National Center for ADR Monitoring since 2016. The system can automatically collect and analyze information (such as diagnoses, medical orders, progress notes, test and examination results, and other information) extracted from the electronic hospital information systems (HIS) in sentinel hospitals (Figure 1)[12]. The connection to HIS makes it possible to simply, actively, and comprehensively obtain real-world drug safety data. At present, CHPS has covered more than 400 hospitals in China and can be used to carry out drug safety research with high operability and accessibility[12; 13].
This study aims to develop anaphylaxis triggers by the Delphi method and construct active surveillance programs based on CHPS. The programs were then ran on 238,194 discharged patients to evaluate their performances and analyze the characteristics, allergens, and management of anaphylaxis in the Chinese population.