Iodinated Contrast Agents and Risk of Hypothyroidism in Young Children in the United States

Study Overview
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Brief Summary
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This study will estimate the incidence of hypothyroidism in a pediatric population of children under age 4, based on data from the US-based Kaiser Permanente Northern California database, which were exposed to iodinated contrast agent through having a diagnostic procedure.

Official Title
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Iodinated Contrast Agents and Risk of Hypothyroidism in Young Children in the United States

Conditions
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Hypothyroidism

Intervention / Treatment
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* Drug: Iodinated contrast agents


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Children under age 4 in the Kaiser Permanente Northern California (KPNC) database, who had a diagnostic procedure with an iodinated contrast agent. Participants should be member of the KPNC for at least 3 months before the iodinated contrast exposure, except where the child is under 3 months of age at time of initial exposure, and 2 weeks after the exposure. Exclusion Criteria: Diagnosis of hypothyroid any time prior to the iodine contrast exposure. Lab values for low thyroid (TSH > 5 mU/L for children) any time before the exposure Thyroid replacement therapy, Hashimoto thyroiditis, or congenital hypothyroidism any time prior to exposure.

Ages Eligible for Study
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Maximum Age: 3 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Iodinated contrast agents<br>Children under age 4 in the Kaiser Permanente Northern California database, who had a diagnostic procedure with an iodinated contrast agent | Drug: Iodinated contrast agents<br>* Use of iodine contrast agents and doses following the decision of the treating physician.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incidence Rate of Hypothyroidism Detected in Routine Clinical Practice | Incidence density rates (IDR) were calculated as the number of cases over the person time at risk where the numerator was the number of cases and the denominator was the person years at risk. | In the 365 days post exposure to an iodinated contrast agent | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Baseline Characteristics (Age) of the Cases With Hypothyroidism and of the Rest of the Cohort |  | Up to 365 days after a diagnostic scan with iodinated contrast agent | 
| Baseline Characteristics (Sex) of the Cases With Hypothyroidism and of the Rest of the Cohort |  | Up to 365 days after a diagnostic scan with iodinated contrast agent | 
| Baseline Characteristics (Year of Hypothyroidism Diagnosis) of the Cases With Hypothyroidism and of the Rest of the Cohort |  | Up to 365 days after a diagnostic scan with iodinated contrast agent | 
| Baseline Characteristics (Type of Iodine Contrast Exposure) of the Cases With Hypothyroidism and of the Rest of the Cohort |  | Up to 365 days after a diagnostic scan with iodinated contrast agent | 
| Baseline Characteristics (Race/Ethnicity) of the Cases With Hypothyroidism and of the Rest of the Cohort |  | Up to 365 days after a diagnostic scan with iodinated contrast agent | 
| Time From First Iodinated Contrast to First Hypothyroidism Event |  | Up to 365 days after a diagnostic scan with iodinated contrast agent | 
| Classification of Subclinical/Manifest Hypothyroidism by Type of Exposure |  | Up to 365 days after a diagnostic scan with iodinated contrast agent | 
| Classification of Hypothyroidism by Etiology |  | Up to 365 days after a diagnostic scan with iodinated contrast agent | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Hypothyroidism,, children,, iodinated contrast agents,, retrospective cohort,, database