Long-Term Antithyroid Drug Treatment of Graves' Disease in Children and Adolescents: A 20-Year Single-Center Experience

A Belgian single centre outcome study of radioiodine treatment in adolescents with Graves' disease

Up to 80% of children/adolescents with Graves' disease (GD) may require second-line treatment with either surgery or radioactive iodine (RAI) therapy after treatment with antithyroid drugs. These interventions aim to induce permanent hypothyroidism, but are not always successful. We aimed to evaluate the initial success rate (within the first year) of RAI treatment and its determining factors as second-line treatment in teenagers with GD. We also assessed the tolerability of RAI therapy and the onset speed of RAI-induced hypothyroidism. We conducted a retrospective chart review of children < 18 years treated with RAI (scaled fixed dose) for GD between January 2007 and December 2022 at the UZ Brussels. Fourteen teenagers treated with RAI were identified. Their ages at time of treatment ranged from 9.8 to 17.3 years, with administered I131 doses between 5.8 and 15.0mCi (median 7.9mCi). All but two patients responded within six months. Thyroxine treatment was started between 4 and 14 weeks (median 9 weeks) after RAI therapy. The time to thyroxine substitution correlated positively with age (Rho = 0.498; p = 0.099) and total I131-dose (Rho = 0.582; p = 0.047). One patient experienced transient RAI induced sialadenitis. None of the patients relapsed during a follow-up period of 1.2 to 13 years. A cure rate of 86% was observed in GD teenagers receiving a second-line RAI treatment, with no major complications. Most patients became hypothyroid within three months, underscoring the importance of early thyroid function monitoring.

Efficacy of Anti-Thyroid Medications in Patients with Graves' Disease

INTRODUCTION

Graves' disease (GD) is an autoimmune disorder characterized by hyperthyroidism due to increased thyroid-stimulating hormone receptor antibodies (TRAb).The treatment of GD often consists of radioactive iodine therapy, anti-thyroid drugs (ATD), or thyroidectomy. Since few studies have collected data on remission rates after treatment with ATD in Saudi Arabia, our study aimed to assess the efficacy and the clinical predictors of GD long-term remission with ATD use.

METHOD

We conducted a retrospective chart review study of 189 patients with GD treated with ATD between July 2015 and December 2022 at the endocrine clinics in King Abdulaziz Medical City in Riyadh. All GD patients, adults, and adolescents aged 14 years and older who were treated with ATD during the study period and had at least 18 months of follow-up were included in the study. Patients with insufficient follow-up and those who underwent radioactive iodine (RAI) therapy or thyroidectomy as first-line therapy for GD were excluded from the study.

RESULTS

The study sample consisted of 189 patients, 72% of whom were female. The patients' median age was 38years (33, 49). A total of 103 patients (54.5%) achieved remission. The median follow-up period for the patients was 22.0 months (9, 36). Patients who achieved remission had lower mean free T4 levels (25.8pmol/l ± 8.93 versus 28.8pmol/l ± 10.82) (P value = 0.038) and lower median TRAb titer (5.1IU/l (2.9, 10.7)) versus (10.5IU/l (4.2, 22.5)) (P value = 0.001) than patients who did not achieve remission. Thirty-five out of 103 patients who achieved remission (34%) relapsed after ATD discontinuation. The patients who relapsed showed higher median thyroid uptake on 99mTc-pertechnetate scan than patients who did not relapse: 10.3% (5.19, 16.81) versus 6.0% (3.09, 12.38), with a P value of 0.03. They also received ATD for a longer period, 40.0 months (29.00, 58.00) versus 25.0 months (19.00, 32.50), with a P value of < 0.0001.

CONCLUSION

The remission of GD was achieved in approximately half of the patients treated with ATD; however, approximately one-third of them relapsed. Lower Free T4 and TRAb levels at diagnosis were associated with remission. Longer ATD use and higher thyroid uptake upon diagnosis were associated with relapse after ATD discontinuation. Future studies are necessary to ascertain the predictors of ATD success in patients with GD.

The association between methimazole tapering and intractable Graves' disease in children

BACKGROUND

The aim of this study was to find predictive factors for intractable Graves' disease (GD).

METHODS

Ninety-three GD patients who visited two pediatric endocrinology clinics from March 2009 to August 2019 were involved in this study. Data were collected on the methimazole (MZ) dosages prescribed from their first visits to their fifth visits. The amount of tapered dosage was presented as a "tapering velocity" (dosage difference (mg/m2)/follow-up interval (months)). The relationship between the tapering velocity and the remission rate of GD was analyzed. Remission of GD was defined as having a total period of MZ treatment less than 5 years with no relapse after MZ withdrawal for at least more than a year.

RESULTS

Of 93 patients diagnosed with GD, 26 patients (28.0%) were classified as the "remission group" and 67 (72.0%) were classified as the "intractable group." The frequency of goiter was significantly higher in the intractable group (p = 0.031). Multivariate logistic analysis revealed that the tapering velocity change from the first to the fifth visit significantly influenced the risk of intractable GD: odds ratio (OR) = 0.598, 95% confidence interval (CI) 0.413-0.865, p = 0.006. An accompanying goiter at the time of diagnosis (OR = 4.706 95% CI 1.315-16.847, p = 0.017) and thyroid stimulation hormone receptor antibody titer (OR = 1.032 95% CI 1.002-1.062, p = 0.034) were also found to be independent factors associated with intractable progress in GD.

CONCLUSION

Difficulty in tapering the MZ dosage in the first 4 months of treatment was an independent predicting factor for intractable GD.

Long-term thionamide antithyroid treatment of Graves' disease

Thionamide antithyroid drugs (ATD) are the treatment of choice for Graves' hyperthyroidism. The major drawback of ATD treatment for 1-2 years is the relapse of hyperthyroidism in about 50% of patients. Recently, it has been shown that ATD treatment for more than five years is accompanied by long-term remission in majority of patients without additional major side effects in both adults and children. Compared to radioactive iodine therapy, long-term ATD results in more favorable outcomes. This review summarizes the evidence on long-term ATD therapy regarding the remission rate of hyperthyroidism, efficacy and safety, indications and mode of therapy in patients with hyperthyroidism.

Clinically practical pharmacometrics computer model to evaluate and personalize pharmacotherapy in pediatric rare diseases: application to Graves' disease

Objectives

Graves' disease (GD) with onset in childhood or adolescence is a rare disease (ORPHA:525731). Current pharmacotherapeutic approaches use antithyroid drugs, such as carbimazole, as monotherapy or in combination with thyroxine hormone substitutes, such as levothyroxine, as block-and-replace therapy to normalize thyroid function and improve patients' quality of life. However, in the context of fluctuating disease activity, especially during puberty, a considerable proportion of pediatric patients with GD is suffering from thyroid hormone concentrations outside the therapeutic reference ranges. Our main goal was to develop a clinically practical pharmacometrics computer model that characterizes and predicts individual disease activity in children with various severity of GD under pharmacotherapy.

Methods

Retrospectively collected clinical data from children and adolescents with GD under up to two years of treatment at four different pediatric hospitals in Switzerland were analyzed. Development of the pharmacometrics computer model is based on the non-linear mixed effects approach accounting for inter-individual variability and incorporating individual patient characteristics. Disease severity groups were defined based on free thyroxine (FT4) measurements at diagnosis.

Results

Data from 44 children with GD (75% female, median age 11 years, 62% receiving monotherapy) were analyzed. FT4 measurements were collected in 13, 15, and 16 pediatric patients with mild, moderate, or severe GD, with a median FT4 at diagnosis of 59.9 pmol/l (IQR 48.4, 76.8), and a total of 494 FT4 measurements during a median follow-up of 1.89 years (IQR 1.69, 1.97). We observed no notable difference between severity groups in terms of patient characteristics, daily carbimazole starting doses, and patient years. The final pharmacometrics computer model was developed based on FT4 measurements and on carbimazole or on carbimazole and levothyroxine doses involving two clinically relevant covariate effects: age at diagnosis and disease severity.

Discussion

We present a tailored pharmacometrics computer model that is able to describe individual FT4 dynamics under both, carbimazole monotherapy and carbimazole/levothyroxine block-and-replace therapy accounting for inter-individual disease progression and treatment response in children and adolescents with GD. Such clinically practical and predictive computer model has the potential to facilitate and enhance personalized pharmacotherapy in pediatric GD, reducing over- and underdosing and avoiding negative short- and long-term consequences. Prospective randomized validation trials are warranted to further validate and fine-tune computer-supported personalized dosing in pediatric GD and other rare pediatric diseases.

Long-term outcomes of anti-thyroid drug treatment in childhood-onset Graves' disease

OBJECTIVE

Outcomes of childhood-onset Graves' disease (GD) and suggested duration of anti-thyroid drug (ATD) therapy have been controversial. This study aimed to determine long-term outcomes following ATD therapy, including remission and relapse rates.

DESIGN, PATIENTS AND MEASUREMENTS

A retrospective study of 265 paediatric patients with GD who were initially treated with ATD was conducted. Long-term outcomes were analysed.

RESULTS

Median (IQR) age at diagnosis was 11.5 (9.4, 13.7) years. Duration of ATD treatment was 4.3 (2.3, 6.7) years and time since diagnosis to the enrolment was 7.1 (3.8, 10.9) years. There were 77, 93 and 95 patients who underwent definitive treatment, had ATD discontinuation, and were still being treated with ATD, respectively. The remission rate was 21% (56 out of 265 patients) and relapse rate was 40% (37 out of 93 patients). Cumulative incidence of first remission increased with the duration of ATD treatment with maximum remission rate at 5.3 years following ATD therapy. Among patients who experienced relapse, approximately 50% had disease relapse which occurred within 1 year after ATD discontinuation. Patients with goitre size of less than 3.5 cm, thyroid-stimulating hormone receptor antibody of less than 10 IU/L, no ophthalmopathy at diagnosis and methimazole dose requirement of less than 0.25 mg/kg/day at 1 year after treatment were more likely to achieve remission.

CONCLUSIONS

Remission rate of childhood-onset GD was relatively low following ATD treatment. Longer-term ATD therapy was associated with increased remission rate. Approximately 50% of patients with relapse had disease relapse within 1 year following ATD discontinuation.

Remission in pediatric Graves' disease treated with antithyroid drug and the risk factors associated with relapse

PURPOSE

To evaluate the characteristics and frequency of remission in pediatric patients with Graves' disease (GD) treated with antithyroid drug (ATD) and to identify factors that may be associated with relapse.

METHODS

Medical records of patients younger than 19 years who presented to the Department of Pediatrics of Queen Elizabeth Hospital Hong Kong with newly diagnosed GD from 1st January 2007 to 31st December 2017 were retrospectively reviewed. Remission was defined as euthyroidism for 12 months or more after discontinuation of ATD treatment and no relapses during the follow-up period. Patients who successfully achieved remission were compared to those who suffered relapse. Factors that may predict occurrence of relapse after ATD treatments were studied, and their odds ratios (ORs) were calculated.

RESULTS

A total of 101 patients was included in this study. Eighty-one patients completed one course of ATD. Eighteen patients (17.8%) successfully achieved remission, and 58 patients (57.4%) experienced relapse after discontinuation of ATD. The remission group received a significantly longer course of ATD therapy than the relapse group (median, 28 months; interquartile range [IQR], 18-48 months in remission group vs. median, 21 months; IQR, 17-26; p=0.024). The OR for relapse was 0.971 (95% confidence interval [CI], 0.946-0.997) in univariate analysis and remained significant after adjustments in the multivariate regression model (OR, 0.961; 95% CI, 0.933-0.989; p=0.008).

CONCLUSION

The remission rate in pediatric patients with GD treated with ATD was low. A longer ATD course was associated with a greater chance of remission in this population.

The relationship between atherosclerotic disease and relapse during ATD treatment

Background

Clinical relapse is a potential risk for traditional antithyroid drug (ATD) treatment in hyperthyroid patients. Evidence suggests that atherosclerotic disease is closely associated with hyperthyroidism, while the relationship between atherosclerosis and relapse remains unclear.

Methods

Two hundred and twenty-five patients with GD who underwent ATD as their first treatment were studied; 88 and 137 patients were categorized as drug reduction relapse and drug reduction remission, respectively. Logistic regression was used to analyze risk factors of drug reduction relapse in patients with GD.

Results

During a median of 48 months followed up 88 patients who relapsed. According to multivariate analyses, atherosclerosis related diseases, FT4, goiter, and anxiety rating scores are independent risk factors for drug reduction. According to K-M survival analysis, patients with atherosclerosis related diseases, FT4 &gt; 18.82 pmol/L, anxiety rating scores &gt; 23, and gradation of goiter ≥ Grade II had a higher risk of relapse than those with lower levels. ROC analysis shown atherosclerosis related diseases significantly improved the predictive accuracy of relapse.

Conclusions

Atherosclerotic disease is closely related to the relapse of hyperthyroidism, ATD treatment in hyperthyroid patients with atherosclerosis should be given more attention.

Update on Pediatric Hyperthyroidism

Typical symptoms which should lead to suspicion of hyperthyroidism are unintentional weight loss, tachycardia, and palpitations, heat intolerance, and hyperactivity. It is diagnosed by suppressed thyroid-stimulating hormone (TSH) with elevated thyroid hormone (TH) levels. Graves' disease (GD) due to antibodies stimulating the TSH receptor is the leading cause, and first-line treatment is with methimazole (MMI). Emerging data suggest MMI treatment, up to 8 years is effective and safe in improving the rate of remission. Radioactive iodine (RAI) and thyroidectomy offer definitive treatment and induce permanent hypothyroidism. Thyroid storm is a life-threatening condition with systemic decompensation and hyperpyrexia. Neonates of mothers with current or past GD are at risk for neonatal hyperthyroidism (NH). Appropriate identification and follow-up of at-risk neonates will reduce complications.