Precautionary Behaviors and Side Effects after Radioiodine for Thyroid Disease: A Prospective Cohort Study.

[BACKGROUND] Radioiodine is an effective treatment for hyperthyroidism and thyroid cancer. Little is known about patients' experiences of radioiodine, yet negative beliefs about other novel treatments can influence adherence to precautionary behaviors and side effect experience post treatment. The current study aims to examine the impact of patients' beliefs about their thyroid condition, radioiodine, and their body on precautionary post-radioiodine behaviors and side effects.

[METHODS] This prospective cohort study enrolled adults receiving a first outpatient dose of radioiodine to treat thyroid cancer or hyperthyroidism. Participants completed questionnaires assessing beliefs and understanding of radioiodine pre-treatment at the end of the initial post-dose restriction period and 4 weeks after receiving radioiodine. We also assessed adherence to precautionary post-treatment behaviors and reported side effects.

[RESULTS] Sixty-six patients enrolled in the study, 63 completed the pre-radioiodine and initial post-dose assessments, and 60 completed all three. Overall, participants poorly recalled clinician-imposed post-treatment precautions, but often engaged in additional self-imposed precautions. On average, participants reported 4-5 radioiodine side effects. Participants' beliefs about radioiodine, their thyroid condition, and their body predicted adoption of additional precautions and side effect attribution ( < 0.05 for each).

[CONCLUSIONS] Patients receiving radioiodine have poor recall and may under-adhere to required postdose precautions while adopting unnecessary self-imposed precautions. Patients with maladaptive beliefs before treatment appear to find radioiodine more burdensome and intrusive during the first 4 weeks after treatment.