Risk of post-contrast thyroid dysfunction in non-toxic goiter: a matched cohort study

OBJECTIVE: To quantify the risk of post-iodinated contrast media (ICM) thyroid dysfunction and identify clinical predictors in adults with nontoxic goiter. DESIGN: Single-center retrospective cohort study. METHODS: We conducted a retrospective cohort study (2010-2023) of adults with intravenous ICM exposure after ≥1-year ICM-free baseline. Nontoxic goiter was identified via ICD codes, with ultrasound as sensitivity analysis. Goiter cases were 1:8 propensity score matched to controls by age, sex, comorbidities, and medications. The primary outcome was thyroid-stimulating hormone (TSH)-defined thyroid dysfunction within 2 years after ICM exposure. Additional sensitivity analyses included cases with concurrent abnormal free T4 or T3 levels, and cases with subsequent thyroid-related medication use. Adjusted odds ratios (aORs) were estimated using logistic regression, and repeated ICM exposure during follow-up was examined as a risk factor. RESULTS: After matching, 1347 goiter cases and 10 776 controls were analyzed. TSH-defined dysfunction occurred in 4.8% vs 1.4% within 2 years (OR, 3.46; 95% CI, 2.57-4.66). Sensitivity analyses using stricter definitions showed consistent results. In adjusted models, nontoxic goiter remained independently associated with dysfunction (aOR, 3.10; 95% CI, 2.39-4.02). Additional predictors included amiodarone use (aOR, 11.34; 95% CI, 8.60-14.94), repeated ICM exposure (aOR, 1.54; 95% CI, 1.34-1.77), and female (aOR, 1.96; 95% CI, 1.69-2.22). Findings were consistent when goiter was defined sonographically (309 vs 2472; OR, 3.76; 95% CI, 2.22-6.38). CONCLUSION: Nontoxic goiter was linked to a 3-fold increased risk of thyroid dysfunction post-ICM, supporting targeted screening, and TSH monitoring in high-risk populations.