The Factors that Affect Thyroid Hormone Replacement Adherence in Patients with Differentiated Thyroid Carcinoma in South Africa

Abstract

Background: Thyroid cancer has become the most common endocrine malignancy, accounting for 1-2% of all malignant tumors worldwide. Most thyroid cancers have an excellent prognosis with 20-year survival rates of more than 95%, however, recurrence and persistent rates are high. Poor adherence to the thyroid replacement hormone jeopardizes any effort to obtain positive outcomes in thyroid cancer patients. Aim: This study aimed to explore and evaluate the most common factors contributing to non-adherence in patients with DTC at CMJAH. Methods: Data from participants with histologically proven DTC, they were patients with previous thyroidectomy with or without lymph node dissection who received therapeutic doses of radioactive iodine. The study was conducted between 01 August and 31 December 2022 at the Department of Nuclear Medicine at the CMJAH. Proportions and percentages were used to summarize categorical variables. Differences were analyzed using the chi-squared test or Fisher’s exact test where appropriate. Continuous variables with a normal distribution were reported using the mean and standard deviation; variables with a skewed distribution were reported using the median with interquartile ranges (IQR). P-values less than 0.05 were considered statistically significant. Stata version 17 (StataCorp) 2021, College Station, TX: StataCorp LLC was used to analyze the de-identified data. Results: Only twenty-one percent of participants were classified as non-adherent to THR, while 79% of the participants were adherent. The majority of the participants, about 89% were female. The most adherent participants were between the ages of 40-59 and were married. Awareness of long-term use of THR as well as self- administration showed an increased adherence. Among the participants who had only one chronic illness, 37 out of 72 were found to be adherent. Long-term use of THR correlated to adherence in 31 participants. Most participants (101) and their families (107) were literate about THR, with 62 and 59 adhering to THR. The majority (120) were informed about THR by the doctors at the clinic. Conclusion: Results were comparable to reported rates in studies conducted in some high-income countries, with the majority of the participants adherent. Self-sufficiency, health literacy, family support, and trusting relationships with health providers contribute the most.