Adverse reactions to iodinated contrast media: prevalence, risk factors and outcome - the results of a 3-year period

Background: Iodinated contrast media (CM) are commonly used. Hypersensitivity reactions to CM occasionally result in morbidity. Risk factors and the role of premedication remain to be investigated. Objective: We sought to explore the prevalence, risk factors and outcome of CM reactions. Methods: The retrospective case-control study was conducted between 2008 and 2010. In total, 55,286 subjects who were exposed to iodinated CM were enrolled to determine the prevalence of CM reactions. The case-control statistical method was applied to determine the risk factors of CM reactions. 579 subjects who had CM reactions were categorised in the case group and 1,175 of the 55,286 subjects who had tolerated CM exposure were randomised for the control group. Results: The overall prevalence of CM reactions was 1.05%. In a multivariate analysis, the history of previous CM reactions, female gender and the history of seafood allergy were significant risk factors for CM reactions. The significant risk factors for the first episode of CM reactions were female gender, the history of seafood allergy and asthma. We found sixteen serious reactions in the immediate reaction group: ten fully recovered after hospitalisation, five fully recovered after out-patient treatment and one died after the administration of CM via an intra-arterial route during coronary angiogram. The most significant risk factor associated with serious reactions was asthma, whereas comorbid cardiovascular disease, male gender, history of seafood allergy and history of previous CM reactions were significant risk factors for mild reactions. Conclusions: The prevalence of CM adverse reactions was as low as 1.05%. Risk factors consist of a history of previous CM reactions, female gender and seafood allergy. Nevertheless, serious immediate reactions could occur particularly in patients with asthma.