# Active Surveillance of Iodinated Contrast Media-Induced Reactions and Associated Risk Factors Among Patients Undergoing Radiologic Procedures in Tertiary Hospitals in Tanzania: A Prospective Cohort Study

## TL;DR

This study in Tanzania found that nearly 40% of patients had reactions to iodinated contrast media during radiologic procedures, with acute reactions being more common than delayed ones.

## Contribution

The study provides new insights into the incidence and risk factors of ICM-induced reactions in a Tanzanian tertiary hospital setting.

## Key findings

- Acute ICM-induced reactions occurred in 39.2% of patients, with gastrointestinal, neurological, and dermatological symptoms being most common.
- Stage 2 renal failure was the strongest risk factor for ICM-induced reactions, with an adjusted risk ratio of 2.143.
- Diabetes mellitus was associated with a lower risk of ICM-induced reactions (adjusted risk ratio = 0.540).

## Abstract

Background: Exposure to iodinated contrast media (ICM), particularly at higher doses, carries significant risks of acute hypersensitivity and organ toxicity, especially involving the kidneys and cardiovascular system. Documenting these reactions is vital for patient safety, risk management, and medico-legal considerations. This study aimed to determine the incidence of ICM-induced adverse reactions and to identify associated risk factors among patients undergoing radiologic imaging in tertiary hospitals in Tanzania.

Materials and methods: This prospective cohort study enrolled 283 patients undergoing contrast-based radiologic procedures between March and May 2024 at two tertiary hospitals in the Ilala district, Tanzania. Data on demographics, drug history, comorbidities, and prior contrast exposure were collected through structured questionnaires and patient files. Blood pressure and BMI were measured, with hypertension defined as BP ≥140/90 mmHg or a history of treatment. Reactions were assessed at baseline and post-procedure at 24, 72, and 168 hours. Data analysis was performed using SPSS version 27 (IBM Corp. Released 2020. IBM SPSS Statistics for Windows, Version 27.0. Armonk, NY: IBM Corp.), applying univariate and multivariate analysis, with p-values <0.05 considered statistically significant.

Results: The incidence of any ICM-induced reaction was 39.2% (111/283). Acute reactions predominated, including gastrointestinal (27.9%), neurological (18.0%), and dermatological (13.5%) symptoms, while delayed events were mainly contrast-associated acute kidney injury (6.3%) and delayed cutaneous reactions (4/111, 3.6%). Significant risk factors included normal BMI (adjusted risk ratio (ARR) = 1.445), overweight (ARR = 1.305), neurological conditions (ARR = 1.496), cardiopulmonary disease (ARR = 1.335), oncologic indications (ARR = 1.350), anemia (ARR = 1.490), and stage 2 renal failure (ARR = 2.143). Interestingly, diabetes mellitus was associated with a lower risk (ARR = 0.540).

Conclusions: These findings highlight that acute reactions are more common than delayed ones, emphasizing the need for careful risk assessment and targeted preventive strategies during contrast procedures.