Article Summary
A Korean study of nearly 116,000 patients found that hypersensitivity reactions to iodinated contrast media are uncommon, occurring in only 0.58% of cases, with most reactions being mild, and prior contrast exposure and previous hypersensitivity reactions identified as the strongest predictors.
- Hypersensitivity reactions occurred in 0.58% of 115,966 patients who received iodinated contrast media between 2016 and 2018
- Severe reactions were rare, affecting just 0.06% of patients with no reaction-related deaths reported
- Prior contrast exposure and previous hypersensitivity reactions were the strongest predictors of adverse reactions
- Asthma, allergy, malignancy, diabetes, and autoimmune disease were independently associated with increased risk
- Higher iodine concentrations showed modest association with mild-to-moderate reactions, but severe reaction rates remained unchanged
A nationwide Korean study of nearly 116,000 patients found hypersensitivity reactions to iodinated contrast media (ICM) were uncommon and usually mild, while identifying prior contrast exposure and previous hypersensitivity reactions as the strongest predictors.
The nationwide retrospective cohort study, published in Investigative Radiology, included 115,966 patients who received ICM between 2016 and 2018. Overall, hypersensitivity reactions occurred in 0.58% of patients, with most classified as mild. Severe reactions occurred in just 0.06% of patients, and no reaction-related deaths were reported.
The strongest predictors of hypersensitivity reactions were previous contrast exposure and a history of prior hypersensitivity reactions. Asthma, allergy, and malignancy were also independently associated with increased risk.
Among patients who received corticosteroid and/or antihistamine premedication, breakthrough reactions still occurred. Previous contrast exposure remained the strongest predictor, while asthma, diabetes mellitus, and autoimmune disease were also independently associated with breakthrough reactions.
The investigators also found that higher iodine concentrations were associated with a modest increase in mild-to-moderate hypersensitivity reactions. However, severe reaction rates remained unchanged regardless of iodine concentration. The authors caution that the association requires prospective validation before it can inform clinical practice.
Caveats for Europe
Dr. Aart J. van der Molen, secretary of the European Society of Urogenital Radiology (ESUR) Contrast Media Safety Committee, said the findings should be interpreted in light of current European clinical practice.
"The study reflects a very specific patient population based on retrospective analysis of insurance claims data with a very high use of premedication which does not represent everyday European practice, even if premedication were used more liberally," he said.
As a result, van der Molen does not believe the findings warrant changes to the ESUR Contrast Media Safety Committee's 2025 recommendations, which recommend a more individualized approach, emphasizing allergy testing and switching to an alternative contrast agent rather than routine premedication for patients with previous moderate-to-severe hypersensitivity reactions.
He noted that, in Europe, premedication is generally reserved for patients with previous moderate or severe reactions rather than those with more limited risk factors. He added that further studies reflecting routine European practice are needed to determine whether contrast agent switching could also benefit lower-risk patient groups.
Van der Molen said he would like to see a large prospective European study conducted in routine clinical practice rather than relying on retrospective insurance claims data. He acknowledged, however, that the cost and complexity of such a study may make it difficult to undertake.
