Finding the Optimal Alternative for Immediate Hypersensitivity to Low-Osmolar Iodinated Contrast

N-(2,3-dihydroxypropyl) carbamoyl side chain: a potentially significant factor for recurrent iodinated contrast medium-related adverse drug reactions

PURPOSE

To determine whether switching to contrast media based on the sharing of N-(2,3-dihydroxypropyl) carbamoyl side chain reduces the recurrence of iodinated contrast media (ICM)-associated adverse drug reactions (ADRs).

MATERIALS AND METHODS

This single-center retrospective study included 2133 consecutive patients (mean age ± SD, 56.1 ± 11.4 years; male, 1052 [49.3%]) who had a history of ICM-associated ADRs and underwent contrast-enhanced CT examinations. The per-patient and per-exam-based recurrence ADR rates were compared between cases of switching and non-switching the ICM from ICMs that caused the previous ADRs, and between cases that used ICMs with common and different carbamoyl side chains from ICMs that caused the previous ADRs. Downgrade rates (no recurrence or the occurrence of ADR less severe than index ADRs) were also compared. Propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) analysis were additionally performed.

RESULTS

In per-patient analysis, switching of ICM showed a lower recurrence rate (switching, 10.4% [100/965] vs. non-switching, 28.4% [332/1168]), with the adjusted odds ratio (OR) of 0.27 (95% CI: 0.21, 0.34; p < 0.001). The result was consistent in PSM (OR, 0.29 [95% CI: 0.22, 0.39]; p < 0.001), IPTW (OR, 0.28 [95% CI: 0.22, 0.36]; p < 0.001), and in per-exam analysis (5.5% vs. 13.8%; OR, 0.32 [95% CI: 0.27, 0.37]; p < 0.001). There was lower per-exam recurrence (5.0% [195/3938] vs. 7.8% [79/1017]; OR, 0.63 [95% CI: 0.47, 0.83]; p = 0.001) and higher downgrade rates (95.6% [3764/3938] vs. 93.3% [949/1017]; OR, 1.51 [95% CI: 1.12, 2.03]; p = 0.006) when using different side chain groups.

CONCLUSION

Switching to an ICM with a different carbamoyl side chain reduced the recurrent ADRs and their severity during subsequent examinations.

CLINICAL RELEVANCE STATEMENT

Switching to an iodinated contrast media with a different carbamoyl side chain reduced the recurrent adverse drug reactions and their severity during subsequent examinations.

Skin Test-Guided Strategy to Select Alternative Iodinated Contrast Media in Patients With Immediate Hypersensitivity Reaction: A Prospective Confirmative Study

BACKGROUND

Iodinated contrast media (ICM) are a common cause of drug-induced immediate hypersensitivity reaction (IHR). Repeated use of ICM is often necessary; therefore, a standardized protocol to prevent recurrence of IHR is required.

OBJECTIVE

We aimed to propose an intradermal skin test (IDT)-guided strategy for previous reactors to prevent recurrence of IHR.

METHODS

We conducted a prospective multicenter study from May 2018 to December 2020 and recruited patients who had experienced IHR to ICM. Once enrolled, the participants underwent IDT with a causative ICM. The alternatives for reexposure were selected using the following protocol: (1) if the IDT with the culprit ICM was positive, further skin tests with other available ICM were conducted to choose IDT-negative agents as alternatives, and (2) if the IDT with the culprit ICM was negative, a randomly changed ICM was used without additional skin tests. The recurrence and severity of hypersensitivity were assessed in subsequent computed tomography examinations. Premedication was administered according to the severity of the index event in all cases.

RESULTS

A total of 496 participants were enrolled, and 299 were reexposed to ICM. Among 269 participants who followed the protocol, 228 (84.8%) completed computed tomography examinations without adverse reactions, and IHR recurred in 16 of 30 participants (53.3%) who did not follow the protocol (P < .001). In addition, application of the protocol reduced the severity of IHR in recurred cases (P = 0.003).

CONCLUSIONS

Our IDT-guided strategy not only reduced recurrence of IHR to ICM but also mitigated the severity in recurred cases. This provides evidence for recommending an IDT to diagnose ICM allergy and find safe alternatives.

Substitution with Low-Osmolar Iodinated Contrast Agent to Minimize Recurrent Immediate Hypersensitivity Reaction

Background The recurrence of hypersensitivity reaction (HSR) to low-osmolar iodinated contrast media (LOCM) remains challenging despite premedication and substitution of the LOCM. Purpose To determine the optimal practical preventive strategy for LOCM substitution in patients with a history of prior immediate HSR to LOCM. Materials and Methods In a retrospective study, patients with an immediate HSR to LOCM before February 2020 and who underwent subsequent exposure to LOCM until March 2021 were enrolled in five tertiary referral hospitals in South Korea. The association of recurrence of an HSR after subsequent LOCM exposures was assessed using multivariate general estimating equation analysis according to age, sex, the severity of the index HSR, premedication, and substituting LOCM based on common carbamoyl side chains, including the N-(2,3-dihydroxypropyl)-carbamoyl and N-(2,3-dihydroxypropyl)-N-methyl-carbamoyl moieties. Results The evaluation included 3800 subsequent LOCM exposures in 1066 patients (mean age, 56.2 years ± 13.5 [SD]; 567 [53%] female and 499 [47%] male patients). The general estimating equation analysis, using 1:1 propensity score matched data for age, sex, HSR severity, and LOCM selection, showed that premedication with corticosteroids significantly reduced recurrent HSR (odds ratio [OR], 0.72; 95% CI: 0.52, 1.00; P = .049). The change to another LOCM with a common side chain had a similar recurrence rate as using the same LOCM (OR, 0.98; 95% CI: 0.64, 1.50; P = .93), whereas the use of a different LOCM without a common side chain significantly lowered HSR recurrence (OR, 0.51; 95% CI: 0.37, 0.69; P < .001) in multivariate general estimating equation analysis. Substitution of an LOCM without a common side chain was effective regardless of the index HSR severity but was more pronounced in moderate-to-severe reactions (OR, 0.30; 95% CI: 0.16, 0.55; P < .001). Conclusion For patients with a previous immediate HSR of any severity to LOCM, alternative LOCM without a common carbamoyl side chain reduced recurrent HSR during subsequent exposures. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by McDonald in this issue.

Incidence and severity of nonionic low-osmolar iodinated contrast medium-related adverse drug reactions in the Republic of Korea: Comparison by generic

We aimed to report the incidence and severity of nonionic low-osmolar iodine contrast medium (ICM)-related adverse drug reactions (ADRs) in the Republic of Korea, by analyzing data from our single tertiary institution and published Korean reports, and to determine whether there is a difference in the incidence of ICM-related ADR by ICM generics. A total of 1,161,419 consecutive contrast-enhanced computed tomography (CT) examinations between January 2016 and December 2021 at Asan Medical Center were included. A systematic search of the literature investigating the incidence of ICM-related ADR in the Republic of Korea published up to December 31, 2021 was performed. We pooled these outcomes with those of our study using a binomial-normal model, and the pooled incidences of ADRs were compared among ICM generics using chi-square tests. Seven studies with a total of 2,570,986 contrast-enhanced CT examinations from 12 institutions were included. The pooled incidences of overall, mild, moderate, and severe ICM-related ADRs in the Republic of Korea were 0.82% (95% CI: 0.61%-1.10%), 0.72% (95% CI: 0.50%-1.04%), 0.11% (95% CI: 0.08%-0.15%), and 0.013% (95% CI: 0.010%-0.018%), respectively. In multiple pairwise comparisons, there were no significant differences in the overall incidence of ADRs between ICM generics, except iomeprol versus iobitridol and iomeprol versus iohexol. For moderate and severe ADRs, there were no significant differences in ADR incidence between ICM generics. The incidence of moderate and severe ICM-related ADRs did not differ among ICM generics. Our results suggest that no restriction is required for selection among nonionic low-osmolar ICMs.

Contrast Agent Selection to Prevent Recurrent Severe Hypersensitivity Reaction to Iodinated Contrast Media Based on Nationwide Database

OBJECTIVE

To investigate the incidence of severe iodinated contrast media (ICM)-related hypersensitivity reaction (HSR) and to find the optimal alternative ICM to reduce the risk of severe HSR recurrence.

METHODS

We retrospectively reviewed 23,383,183 cases of ICM administration between January 2015 and December 2019 from the nationwide health insurance database. We classified ICMs based on generic profiles and the presence of N-(2,3-dihydroxypropyl) carbamoyl side chains. The incidence of severe and recurrent severe HSRs was calculated, and χ2 tests were performed to compare the prevalence of severe HSR according to ICM groups. In addition, logistic regression analyses were used to assess differences between ICM groups.

RESULTS

The incidence of severe HSRs was 1.92% (450,067 of 23,282,183). Among 1,875,245 individuals who received ICM twice on different days, severe HSR occurred in 40,850 individuals, and severe HSR recurred in 3319 individuals (8.12%). The risk of recurrence significantly decreased when the ICM changed (9.24% vs 7.08%, P < 0.001), especially when the ICM changed to one with a different side chain (6.74%, P < 0.001). In addition, compared with the reuse of the culprit agent, using combinations of iobitridol/iohexol (odds ratio [OR], 0.696; P = 0.04), iohexol/iopamidol (OR, 0.757; P = 0.007), iopamidol/iohexol (OR, 0.447; P < 0.001), and ioversol/iohexol (OR, 0.683; P = 0.04) reduced the risk of recurrence of severe HSR.

CONCLUSIONS

Changing the culprit ICM to that with a different side chain can reduce severe HSR recurrence. The optimal choice of an alternative ICM depends on the causative agent.

Stratified assessment and warning regimen for prevention of acute adverse reactions to iodinated contrast media: results of 150,343 cases in a tertiary hospital

For contrast-enhanced CT examinations, there is a lack of comprehensive optimal management strategies of risk factors to reduce the risk of iodinated contrast media (ICM)-induced acute adverse reactions (AAR). Here, we determine the relationship between the rate of ICM-AAR and a stratified assessment and warning (SAW) regimen, which integrated risk identification, stratification, early warning, and prevention. A total of 120,822 cases in the conventional assessment period (58 years ± 15, 55.25% men) and 150,343 cases (58 years ± 14, 55.83% men) in the SAW period were enrolled. The results showed that the total AAR incidence in the SAW period (414/150,343, 0.28%) was lower than that in the conventional assessment period (506/120,822, 0.42%, P < 0.001), in which the proportion of AAR patients decreased by one-third. It mainly presented as decreases in mild and moderate reactions (P < 0.001), and a decrease in the proportion of moderate AAR patients (P = 0.001). Subgroup analysis showed lower mild and moderate AAR incidence in patients with different risk levels and with different ICM injection parameters following SAW regimen. We concluded that SAW regimen was associated with lower incidence of mild and moderate AAR, and decreased proportion of moderate AAR patients, which held potential for improved ICM safety.

Differences in the Recurrence Rate of Immediate Adverse Drug Reactions According to the Components of Alternative Contrast Media: Analysis of Repetitive Computed Tomography Cases in a Single Tertiary Hospital

INTRODUCTION

The recurrence rates of immediate adverse drug reactions (ADRs) to the alternative radiocontrast media (RCM) are not well known. Previous studies suggest selection of alternative RCM considering carbamoyl side chains; however, its usefulness for preventing the recurrence of ADRs has not been clearly verified.

OBJECTIVE

The aim of this study was to verify the recurrence rate of immediate ADRs according to the alternative RCM.

METHOD

This retrospective study analyzed 6420 contrast-enhanced computed tomography (CT) cases of 2009 patients registered in the ADR system from 861,664 CT cases in a single tertiary hospital between 2015 and 2020. Iohexol, iopromide, iobitridol, and iopamidol were used for CT. According to the carbamoyl side chains present, iohexol belongs to group 1, iopromide belongs to groups 1 and 2, iobitridol belongs to group 2, and iopamidol belongs to group 3.

RESULTS

Replacing iobitridol with iopamidol (odds ratio [OR] 2.595, 95% confidence interval [CI] 1.48-4.550) or iopromide (OR 3.354, 95% CI 1.420-7.926) as the subsequent RCM was associated with increased recurrence, while replacing iopamidol with iobitridol (OR 0.506, 95% CI 0.282-0.908) and iopromide with iohexol (OR 0.355, 95% CI 0.177-0.711) was associated with decreased recurrence. Other changes did not influence the recurrence of ADRs.

CONCLUSIONS

The recurrence of immediate ADRs increased in certain RCM combinations of preceding and subsequent CT scans, and the RCMs did not show cross-reactivity. Therefore, the clinical benefit of the alternative RCM considering cross-reactivity is limited. This result suggests that the side chains of RCM do not have an important role in the recurrence of immediate ADRs.

Risk of Hypersensitivity Reactions to Iopromide in Children and Elderly: An Analysis of 132,850 Patients From 4 Observational Studies and Pharmacovigilance Covering >288 Million Administrations

PURPOSE

The aim of this study was to analyze the risk of hypersensitivity reactions (HSRs) to iopromide in children and elderly patients in comparison to adults.

MATERIALS AND METHODS

Four observational studies were pooled and analyzed (analysis I). In addition, spontaneous reports from 1985 to 2020 from the pharmacovigilance database were evaluated (analysis II). All patients received iopromide for angiographic procedures or contrast-enhanced computed tomography in various indications. In analysis I, a nested case-control analysis, including a multivariable logistic regression model, based on pooled observational study data, was performed. Cases were defined as patients with a typical and unequivocal HSR; controls were patients without any recorded reaction. In analysis II, all spontaneous reports on HSRs after iopromide administration recorded in the pharmacovigilance database were descriptively analyzed. Exposure estimates on the size of the exposed age groups were derived from sales data and data from market research. The primary target variable was the risk of HSR to iopromide in children (<18 years) and elderly patients (≥65 years) compared with adults (≥18 to <65 years).

RESULTS

In analysis I, a total of 132,850 patients were included (2978 children, 43,209 elderly, and 86,663 adults). Hypersensitivity reactions were significantly less frequent in children (0.47%) and elderly (0.38%) compared with adults (0.74%). The adjusted odds ratio (vs adults) for children was 0.58 (95% confidence interval, 0.34-0.98; P < 0.043), and that for the elderly was 0.51 (95% confidence interval, 0.43-0.61; P < 0.001), indicating a lower risk for both subpopulations as compared with adults. In analysis II, of the overall >288 million iopromide administrations, 5.87, 114.18, and 167.97 million administrations were administered to children, elderly, and adults, respectively. The reporting rate for HSRs in children (0.0114%) and elderly (0.0071%) was significantly lower as compared with adults (0.0143%) (P < 0.0001).

CONCLUSIONS

Hypersensitivity reactions to iopromide were significantly less frequent in children and elderly compared with adults.

Diagnosis and Prevention of Hypersensitivity Reactions to Iodinated Contrast Media

Iodinated contrast media (ICM) have become one of the major causes of drug hypersensitivity reactions (HSRs) related to increasing numbers of ICM-based radiological imaging procedures. Strategies for diagnosing and preventing ICM-induced HSRs have not been uniformly standardized yet. However, advances have been made based on the results of recent research. A previous history of hypersensitivity to ICM is the most significant risk factor for developing HSR by ICM. Avoidance of culprit agents and premedication is the main strategy to prevent recurrences of HSRs in high-risk patients. In addition, we strongly recommend identifying sensitized ICM using skin tests to determine immunoglobulin E-mediated or delayed-type allergy and to guide the choice of an alternative contrast agent. ICM provocation test procedures have been established and are helpful in selected cases. In this paper, we review how to evaluate patients who have experienced immediate or delayed HSRs caused by ICM to minimize the risk of recurrence and discuss unmet needs that require further research.