Medical therapy of Graves' disease: effect on remission rates of methimazole alone and in combination with triiodothyronine

Effect of Addition of Thyroxine in the Treatment of Graves' Disease: A Systematic Review

Graves' disease is the most common cause of hyperthyroidism. Antithyroid drugs, radioiodine ablation, and surgery are the main treatments. Research has demonstrated that adding thyroxine to antithyroid therapy can improve the remission rate, and many similar studies have been conducted subsequently. The purpose of this systematic review was to investigate whether adding thyroxine to various treatments for Graves' disease has a clinical benefit in remission/relapse rate, stable thyroid function, occurrence of Graves' ophthalmopathy, etc. A total of 27 studies were included, and the risk of research bias was moderate to high. We discuss the role of thyroxine both in pharmacological and non-pharmacological therapeutic regimens. Overall, the available evidence does not support the indiscriminate addition of thyroxine to various treatments for Graves' disease, especially in combination with oral antithyroid drugs. Further clinical studies are required to explore the indications of thyroxine addition in the treatment of Graves' disease.

Predictors of Initial and Sustained Remission in Patients Treated with Antithyroid Drugs for Graves' Hyperthyroidism: The RISG Study

Purpose. To study predictors of attaining (part 1) and sustaining (part 2) remission in patients with Graves' hyperthyroidism (GH) treated with antithyroid drugs (ATD). Methods. In the prospective first part, the included patients were treated with ATD until a prespecified definition of remission (thyrotropin > 0.4 mU/L and TSH-receptor antibodies (TRAb) ≤ 1. 0 IU/L in a patient receiving a methimazole dose ≤ 5 mg/day, on two occasions two months apart) was met, or for 24 months. In the second part, patients attaining remission in part 1 were randomized to treatment or observation and followed until relapse or for 24 months. Results. 173 patients completed study 1 and 53% attained remission. TRAb and age were the only significant predictors of remission. Patients with baseline TRAb below vs above 10 IU/L attained remission in 63% compared to 39%, and 5 months priorly (p<0.001). In study 2, 96.4% of the patients randomized to treatment (n=33) sustained remission compared to 66% in the observation group (n=33). Treatment arm was the only significant parameter (p<0.001) of sustained remission. Conclusion. Baseline TRAb was prognostic for attaining remission in GH. Consecutive TRAb measurements during treatment were not worthwhile, but a single measurement after 6-8 months in patients with initial TRAb < 10 IU/L could substantially shorten the treatment period in a subgroup of patients. Only 3.6% of the patients in remission experienced relapse during follow-up when treated with a combination of fixed low dose methimazole and L-T4. ClinTrial.gov registration number is  NCT00796913.

Increased Human Interleukin-32 Expression Is Related to Disease Activity of Graves' Disease

Recently, abnormal expression of interleukin-32 (IL-32) has been involved in various inflammatory or autoimmune diseases, but the level of IL-32 expression in Graves' disease (GD) is still unknown. This study is aimed to explore the human IL-32 expression in GD and the association of IL-32 expression with the disease activity of GD. A total of 125 GD patients and 97 normal controls (NC) were recruited in this study. We examined IL-32 mRNA level in peripheral blood mononuclear cells (PBMCs) of 43 GD patients and 41 controls using real-time polymerase chain reaction (RT-PCR). Serum IL-32 level of 40 GD patients and 34 controls was measured by enzyme linked immunosorbent assay (ELISA). In another cohort including 42 GD patients and 22 controls, we detected the percentages of IL-32α⁺ cells, CD4⁺IL-32α⁺T cells, and CD4^-IL-32α⁺ cells in PBMCs by flow cytometry. In GD patients, IL-32 mRNA expression was dramatically higher than that in controls (P < 0.001) and positively associated with FT3 (P = 0.036, r = 0.321). Subgroup analysis revealed that IL-32 mRNA level was elevated in both newly onset GD and refractory GD group (P < 0.01, P < 0.001, respectively) compared with controls. Furthermore, in refractory GD group, the IL-32 mRNA expression also positively correlated with FT3 (P = 0.019, r = 0.560). In addition, serum IL-32 level was notably higher in GD patients than that of controls (P < 0.01). Subgroup analysis also indicated that serum IL-32 level in both newly onset GD and refractory GD group was higher in comparison with controls (P = 0.015, P = 0.023, respectively) and serum IL-32 level in refractory GD patients positively correlated with TRAb (P = 0.043, r = 0.481). The percentages of IL-32α⁺ cells, CD4⁺IL-32α⁺ T cells, and CD4^-IL-32α⁺ cells were all significantly enhanced in GD patients compared with controls (P = 0.005, P = 0.017, P = 0.016, respectively). IL-32 and IL-32α⁺ cells may be associated with the pathogenesis of GD. IL-32 may become a promising target for the treatment of GD.

The phenotype of newly diagnosed Graves' disease in Italy in recent years is milder than in the past: results of a large observational longitudinal study

OBJECTIVE

The Merseburg triad (hyperthyroidism, goiter, and orbitopathy) characterizes classical description of Graves' disease (GD). Aim of this observational, longitudinal study was to evaluate the current clinical features of newly diagnosed GD in Italy.

MATERIALS AND METHODS

In two Northern Italy centers (Varese and Pavia), 283 consecutive patients (211 women, 72 men; mean age 47.4 years) with newly diagnosed GD were recruited in the years 2010-2014. Diagnosis was based on established criteria, and thyroid volume was assessed by ultrasonography. A clinical severity score (CSS) to assess the overall disease severity was developed by grading each component of the Merseburg triad.

RESULTS

At diagnosis, 45 % of patients had no goiter, and 30 % had a small goiter. The proportion of goitrous patients was much lower than in two Italian studies performed 20-30 years ago. Hyperthyroidism was subclinical in 16 % and mild in 29 % of patients, and Graves' orbitopathy was present in 20 %, usually mild, and active in only 2.5 % of patients. Using the CSS, less than half (44 %) of the patients had severe GD, while 22 % had mild and 34 % moderate disease. CSS was associated with a significantly higher risk of poorly controlled hyperthyroidism at 6 months.

CONCLUSIONS

In Italy, a relevant proportion of Graves' patients at diagnosis have mild to moderate GD; about half of them have no goiter, slightly less than one-fifth have subclinical hyperthyroidism, and only 20 % have GO. Thus, the clinical phenotype of GD is milder than in the past, possibly due to both earlier diagnosis and treatment, and improved iodine nutrition.

Differential cytokine expression detected by protein microarray screening in peripheral blood of patients with refractory Graves' disease

OBJECTIVE

The prognosis of Graves' disease (GD) varies among patients. However, the immune pathogenesis of refractory GD is still unknown. The aim of this study was to explore the cytokine expression profile associated with refractory GD.

METHODS

Preliminary cytokine protein microarray screening was performed to detect differentially expressed cytokines in the plasma of four patients with refractory GD and four patients with stable GD. Some differentially expressed cytokines were then validated in plasma by enzyme-linked immunosorbent assay (ELISA) and in peripheral blood mononuclear cells (PBMCs) by quantitative real-time polymerase chain reaction (qRT-PCR) on another independent set of samples.

RESULTS

We found that 21 cytokines were differentially expressed between patients with intractable GD and those in remission, including 18 upregulated and 3 downregulated cytokines with a fold change >1·30 and <0·77, respectively. Intractability-related elevation of three cytokines (IL-4, IL-6 and IL-10) was validated by ELISA in plasma on another GD cohort with 30 patients in recurrence and 14 in remission (t-test, P = 0·035, 0·033 and 0·041, respectively). Furthermore, mRNA expression of IL-4, IL-6 and IL-10 in PBMCs, detected by qRT-PCR, was significantly elevated in patients with refractory GD compared with those in remission (P = 0·039, 0·047 and 0·042, respectively).

CONCLUSION

The severity of GD is associated with the aberrant expression and secretion of several cytokines that may serve as potential biomarkers and predictors for disease prognosis. Targeting these cytokines or their receptors may also lead to a novel therapeutic intervention for GD.

Antithyroid drug regimen for treating Graves' hyperthyroidism

BACKGROUND

Antithyroid drugs are widely used in the therapy of hyperthyroidism. There are wide variations in the dose, regimen or duration of treatment used by health professionals.

OBJECTIVES

To assess the effects of dose, regimen and duration of antithyroid drug therapy for Graves' hyperthyroidism.

SEARCH STRATEGY

We searched seven databases and reference lists.

SELECTION CRITERIA

Randomised and quasi-randomised trials of antithyroid medication for Graves' hyperthyroidism.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed risk of bias. Pooling of data for primary outcomes, and select exploratory analyses were undertaken.

MAIN RESULTS

Twenty-six randomised trials involving 3388 participants were included. Overall the quality of trials, as reported, was poor. None of the studies investigated incidence of hypothyroidism, changes in weight, health-related quality of life, ophthalmopathy progression or economic outcomes. Four trials examined the effect of duration of therapy on relapse rates, and when using the titration regimen 12 months was superior to six months, but there was no benefit in extending treatment beyond 18 months. Twelve trials examined the effect of block-replace versus titration block-regimens. The relapse rates were similar in both groups at 51% in the block-replace group and 54% in the titration block-group (OR 0.86, 95% confidence interval (CI) 0.68 to1.08) though adverse effects (rashes (10% versus 6%) and withdrawing due to side effects (16% versus 9%)) were significantly higher in the block-replace group. Three studies considered the addition of thyroxine with continued low dose antithyroid therapy after initial therapy with antithyroid drugs. There was significant heterogeneity between the studies and the difference between the two groups was not significant (OR 0.58, 95% CI 0.05 to 6.21). Four studies considered the addition of thyroxine alone after initial therapy with antithyroid drugs. There was no significant difference in the relapse rates between the groups after 12 months follow-up (OR 1.15, 95% CI 0.79 to 1.67). Two studies considered the addition of immunosuppressive agents. The results which were in favour of the interventions would need to be validated in other populations.

AUTHORS' CONCLUSIONS

The evidence suggests that the optimal duration of antithyroid drug therapy for the titration regimen is 12 to 18 months. The titration (low dose) regimen had fewer adverse effects than the block-replace (high dose) regimen and was no less effective. Continued thyroxine treatment following initial antithyroid therapy does not appear to provide any benefit in terms of recurrence of hyperthyroidism. Immunosuppressive therapies need further evaluation.

Prevention of relapse of Graves' disease by treatment with an intrathyroid injection of dexamethasone

INTRODUCTION

Antithyroid drugs are widely used in the treatment of Graves' disease (GD), but the relapse rate is very high after therapy withdrawal. We evaluated the reduction effects of intrathyroid injection of dexamethasone (IID) on the relapse rate of hyperthyroidism in patients with newly diagnosed GD.

PATIENTS AND METHODS

A total of 191 patients with GD completed the study. After 6 months of treatment with methimazole (MMI), the patients were randomly assigned to receive either MMI (96 patients) alone or MMI combined with IID (MMI+IID; 95 patients) treatment for 3 months, followed by continuing a dose of MMI that would maintain euthyroidism for the next 9 months in all of the patients. After withdrawal of the medical therapy, patients were followed for 24 months, and the relapse rate of hyperthyroidism was evaluated.

RESULTS

No statistical difference was observed in the levels of serum FT(4), TSH, or TSH receptor antibodies (TR-Ab), the thyroid volume, or the TR-Ab positive rate between the two groups at month 6. After the next 3 months of treatment with MMI+IID or MMI alone, the levels of TSH increased significantly, and the levels of serum TR-Ab, the TR-Ab positive rate, and thyroid volume decreased significantly in the MMI+IID group compared with the MMI group. Seven patients (7.4%) experienced a relapse of overt hyperthyroidism in the MMI+IID group and 49 patients (51%) in MMI group during the 2-yr follow-up period (P < 0.001).

CONCLUSIONS

MMI+IID treatment is helpful to prevent relapse of hyperthyroidism in GD after medical therapy withdrawal.

Long-term follow-up of patients with hyperthyroidism due to Graves' disease treated with methimazole. Comparison of usual treatment schedule with drug discontinuation vs continuous treatment with low methimazole doses: a retrospective study

Antithyroid drugs may be proposed as the firstline therapy for hyperthyroidism due to Graves' disease since some patients undergo prolonged remission after drug withdrawal. On the other hand, some studies, though controversial, indicated that methimazole (MMI) has some immunomodulating activity. We retrospectively analyzed 384 consecutive patients newly diagnosed with Graves' disease in the years 1990-2002 to ascertain whether long-term therapy with low doses of MMI may prevent relapse of thyrotoxicosis. Two hundred and forty-nine patients were included in our study. The date of reduction of MMI dose to 5 mg/day was considered time 0 for survival analysis. In 121 MMI was discontinued in less than 15 months after time 0 (group D), while in the remaining 128 a daily MMI 2.5-5 mg dose was maintained (group M). One hundred and thirty-five patients were excluded for inadequate response to MMI, relapse of thyrotoxicosis that could be related to an improper withdrawal or reduction of MMI, inadequate or too short followup, iodide contamination, steroid or interferon therapy, pregnancy or post-partum. D and M groups did not differ for clinical and hormonal parameters except age, which was lower in D (p=0.019). Age > vs < 35 yr was relevant in survival analysis; therefore patients were divided in 2 groups according to this age cut-off. In younger patients relapse of thyrotoxicosis occurred in 15 patients of group D 2.4-39.6 months (median 19.0) after time 0, and 8 M after 5.9-40.0 (21.3) months, while 14 D and 5 M maintained euthyroidism until the end of the observation after 31.8-95.3 (56.6) months and 30.4-62.1 (46.5) months, respectively. Survival analysis indicated that the risk of relapse was similar in group D and M. In older patients relapse of thyrotoxicosis occurred in 40 patients of group D after 8.2-65.8 (25.4) months and 29 M after 5.8-62.5 (22.4) months, while 52 D and 86 M maintained euthyroidism until the end of the observation, 20.1-168.0 (46.7) months and 24.1-117.4 (53.4) months respectively. Survival analysis indicated that the risk of relapse was increased in group D. Therefore long-term treatment with low doses of MMI seems to prevent relapse in Graves' disease in patients above 35 yr of age. This should be confirmed in a prospective study.

An update on the pharmacological management of hyperthyroidism due to Graves' disease

Pharmacological treatment, usually by thionamides (carbimazole, methimazole, propylthiouracil) is, in addition to radioiodine therapy and thyroidectomy, one of the available therapies for Graves' hyperthyroidism. Thionamides represent the treatment of choice in pregnant women, during lactation, in children and adolescents and in preparation for radioiodine therapy or thyroidectomy. Side effects are relatively frequent but are in general mild and transient. Two main regimens are available: titration method (use of the lowest dose maintaining euthyroidism; duration: 12-18 months) and block-and-replace method. Neither one has clear advantages in terms of outcome but the latter method is associated with more frequent side effects. Hyperthyroidism relapses in approximately 50% of patients, to whom ablative therapy should be offered.

A systematic review of drug therapy for Graves' hyperthyroidism

We assessed the effects of dose, regimen and duration of anti-thyroid drug therapy for Graves' thyrotoxicosis on recurrence of hyperthyroidism, course of ophthalmopathy, adverse effects, health-related quality of life and economic outcomes. We undertook a systematic review and meta-analyses of randomised controlled trials (RCTs). We identified RCTs regardless of language or publication status by searching six databases, and trial registries. Dual, blinded data abstraction and quality assessment were undertaken. Trials included provided therapy for at least 6 months with follow-up at least 1 year after drug cessation. Fixed or random effects meta-analyses were used to combine study data. Twelve trials compared a Block-Replace regimen (requiring a higher dose of anti-thyroid drug treatment) with a Titration regimen. Overall, there was no significant difference between the regimens for relapse of hyperthyroidism (relative risk (RR) = 0.93, 95% confidence interval (CI) 0.84 to 1.03). Participants were more likely to withdraw due to adverse events with a Block-Replace regimen (RR = 1.89, 95% CI 1.25 to 2.85). Prescribing replacement thyroxine, either with the anti-thyroid drug treatment, or after this was completed, had no significant effect on relapse. Limited evidence suggested 12-18 months of anti-thyroid drug treatment should be used. The titration regimen appeared as effective as the Block-Replace regimen, and was associated with fewer adverse effects. However, relapse rates over 50% and high participant drop-out rates in trials mean that the results should be interpreted with caution, and may suggest that other strategies for the management of Graves' disease, such as radioiodine, should be considered more frequently as first-line therapy. There were no data on the course of ophthalmopathy, health-related quality of life and economic outcomes.

Sensitive thyrotropin and thyrotropin-receptor antibody determinations one month after discontinuation of antithyroid drug treatment as predictors of relapse in Graves' disease

OBJECTIVE

After primary successful antithyroid drug treatment (ATDT), Graves' disease has a relapse rate of 30% to 50%. Previous studies have evaluated age, gender, goiter volume, smoking habits, and the presence of thyrotropin-receptor antibodies (TRAb) as predictive markers to facilitate an individualized patient management. Despite higher sensitivity and specificity of the new second generation human TSH-receptor assay, the predictive value of TRAb for relapse of hyperthyroidism is still controversial. In a recent prospective multicenter study we have previously shown that suppressed or low TSH values predict both early (persistence) and late relapse of Graves' disease. We now present a more detailed analysis of the predictive value of TSH and TRAb for recurrent hyperthyroidism.

METHODS

Four weeks after withdrawal of ATDT, 96 patients were available for thyroid function tests, including a sensitive third-generation TSH assay and a second-generation recombinant TSH receptor assay. Relapse of Graves' disease was evaluated for a total follow-up of 2 years.

RESULTS

Within 2 years, 47 of 96 patients (49%) developed relapse of hyperthyroidism. Nine patients relapsed within the first 4 weeks after withdrawal of ATDT and were thus considered to have persistent Graves' disease. Ten of 15 other patients with TSH levels below 0.3 mU/L without overt hyperthyroidism relapsed within 2 years. Twenty-five of 65 patients with normal TSH (0.3-3.0 mU/L) and 3 of 4 patients with TSH values above 3 mU/L also had recurrent hyperthyroidism. After ATDT cessation, TSH had a positive predictive value of 70% and a negative predictive value of 62% (specificity 85%) for relapse of Graves 'disease. Mean TRAb levels in the group of patients with relapse were significantly higher (11.1 IU/L +/- 0.17) than TRAb values in the remission group (4.5 IU/L +/- 0.6), p < 0.001. Using a cutoff value of 1.5 IU/L, TRAb had low positive and negative predictive values of 49% and 54%, respectively (specificity, 14%), but with a cutoff level of 10 IU/L, predictive values improved to 83% and 62%, respectively (specificity, 92%). Combination of TSH and TRAb determinations did not further improve prediction of relapse. Other factors such as gender, age, goiter volume, smoking habits, presence of thyroid-associated ophthalmopathy, and urinary iodine excretion did not show a significant influence on relapse rate.

CONCLUSION

Low TSH values 4 weeks after ATDT withdrawal predict relapse of Graves' disease, both early (persistence) and, to a lesser extend, within 2 years of follow-up. Also, TRAb above 10 IU/L found in a small subset of patients, correlated with a higher relapse rate.

[Cost-effectiveness of the clinical treatment of Grave's disease in a public University Hospital: a retrospective analysis and prospective projection for a therapeutic approach]

The aim of the present study was to evaluate a new proposal for increasing compliance to the clinical management of patients with Graves' disease (GD) in a large and public University Hospital. The patients were carefully selected (no previous GD treatment, goiter volume less than 6 mL must be living in the metro area of São Paulo), received medication at no cost, were contacted frequently by the social worker and alerted for the date of consultation and only referred to a single endocrinologist during all phases of treatment. We recruited 229 patients with GD that were initially treated with methimazole (MMI--60 mg q.d) in a single daily dose followed by a combination of MMI (20 mg) plus L-T4 (100 microg) daily for 24 months. Only 83 patients (36.2%) completed the protocol and were subdivided in: Group 1 (n= 34) that were in remission for 3 years after discontinuation of the MMI and Group 2 (n= 49) that presented recurrence of GD between 2 and 36 months without MMI. Predictive factors associated with remission were: decrease of the glandular volume, serum TG< 40 ng/mL and normal TRAb values. We concluded that in spite of a careful protocol planned to increase compliance, more than 60% of patients with GD did not complete the therapeutic trial and were referred for radioiodine treatment. The solution for this low therapeutic success for GD should be the possible identification of factors that would indicate patients that are not inclined to follow a long period of clinical therapy.

[Evaluation of the medical treatment of Graves' disease (GD)]

The treatment of Graves' disease (GD) with antithyroid drugs (ATD) leads to remission of the disease in approximately half of patients treated for at least six months, and the overall relapse rate is high, ranging from 60% to 80%. The presence of prognostic features for achieving a remission after medical treatment is a matter of discussion in the literature. The aim of this study is to evaluate the effect of different ATD regimens available in Brazil (propylthiouracil--PTU and methimazole--MMI) on remission and relapse rates of GD, as well as to determine possible predictors of remission and relapse of the disease and the side effects profile. We reviewed the records from all patients submitted to medical treatment of GD (and with no report of prior treatment of the disease) for at least six months and followed for at least 12 months after the drug withdrawal at Hospital Universitário Clementino Fraga Filho (HUCFF), between October 1978 and August 2003. We identified 127 patients, with the age ranging from 18 to 88 years (mean 39.3 +/- 12.8). Remission was observed in 58 patients (45.7%) and relapse occurred in 31 (53.4%), at a mean period of 14.5 +/- 16.1 months. We verified that the duration of symptoms before the beginning of medical treatment, age and gender did not influence the rate of remission and the relapse risk, whereas the presence of large goiter size (> 40 grams), Graves' ophthalmopathy and use of high daily doses of ATD (> or = 600 mg of propylthiouracil/60 mg of methimazole MMI) were associated with a decreased remission rate. Moreover, patients who presented a TSH measurement < 0.4 microIU/mL between 4 to 5 weeks after the drug withdrawal showed an increased relapse cumulative probability. In conclusion, our results confirms that lasting remission rate of GD treated with ATD is relatively low. We concluded that the combination of goiter size > 40 g, ophthalmopathy, and use of daily doses of PTU > or = 600 mg or MMI > or = 60 mg was vigorously related to lack of remission of GD. Furthermore, TSH measurement between 4 to 5 weeks after the drug withdrawal seems to be a useful tool to determine the remission chance and the relapse risk of the disease.

Antithyroid drug regimen for treating Graves' hyperthyroidism

BACKGROUND

Antithyroid drugs are widely used in the therapy of hyperthyroidism. There are wide variations in the dose, regimen or duration of treatment used by health professionals.

OBJECTIVES

To assess the effects of dose, regimen and duration of antithyroid drug therapy for Graves' hyperthyroidism.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (Central), MEDLINE, EMBASE, BIOSIS, CINAHL, HEALTHSTAR, Current Controlled Trials and reference lists. We contacted investigators and hand searched conference abstracts. Most recent search: July 2004.

SELECTION CRITERIA

Randomised and quasi-randomised trials of antithyroid medication for Graves' hyperthyroidism were used.

DATA COLLECTION AND ANALYSIS

Trial allocation to included, excluded and awaiting assessment categories was made by consensus. Two reviewers independently extracted data and assessed trial quality. Pooling of data for primary outcomes, and select exploratory analyses were undertaken.

MAIN RESULTS

Twenty-three randomised trials involving 3115 participants were included. Overall the quality of trials as reported was poor; specifically in terms of allocation concealment, assessor blinding and loss to follow-up. Four trials examined the effect of duration of therapy on relapse rates of Graves' hyperthyroidism. In one trial using the Titration regimen, longer duration therapy (18 months) had significantly fewer relapses (37% versus 58%) than six month therapy (Odds ratio (OR) 0.42, 95% confidence interval (CI) 0.18 to 0.96). In one quasi-randomised trial using the Block-Replace regimen, there was no significant difference between the six and 12 month (relapses rates 41% versus 35%) arms of the study. Extending the duration of therapy to over 18 months was not associated with improved relapse rates (Peto OR 0.75, 95% CI 0.39 to 1.43). Twelve trials examined the effect of Block-Replace versus Titration regimen. The relapse rates were similar in both groups at 51% in the Block-Replace group and 54% in the Titration group (Peto OR 0.86, 95% CI 0.68 to 1.08). Participants reporting rashes (10% versus 5%) and withdrawing due to side effects (16% versus 9%) were significantly higher in the Block-Replace group compared to the Titration group respectively. Three studies considered the addition of thyroxine with continued low dose antithyroid therapy after initial therapy with antithyroid drugs. There was significant heterogeneity between the studies and the difference between the two groups were not significant (Odds ratio 0.58, 95% CI 0.05 to 6.21). Four studies considered the addition of thyroxine alone after initial therapy with antithyroid drugs. There was no significant difference in the relapse rates between the groups after 12 months follow-up with relapse rates being 31% (88/282) with thyroxine and 29% (82/284) with placebo (Peto OR 1.15, 95% CI 0.79 to 1.67).

AUTHORS' CONCLUSIONS

The evidence (based on four studies) suggests that the optimal duration of antithyroid drug therapy for the Titration regimen is 12 to 18 months. The six month Block-Replace regimen was found to be as effective as the 12 month treatment in one quasi-randomised study. The Titration (low dose) regimen had fewer adverse effects than the Block-Replace (high dose) regimen and was no less effective in trials (based on 12 trials) of equal duration. Continued thyroxine treatment following initial antithyroid therapy does not appear to provide any benefit in terms of recurrence of hyperthyroidism. The incidence of hypothyroidism was not reported and there were no deaths reported in the study populations.

Hyperthyroidism: advantages and disadvantages of medical therapy

The most common causes of hyperthyroidism are Graves' disease, toxic nodular goiter, and iodine-induced hyperthyroidism. Hyperthyroidism can be treated medically with antithyroid drugs or radioactive iodine, or surgically. Multiple clinical factors must be weighed when choosing a treatment modality. All of the available forms of therapy have advantages and disadvantages, and treatment choices must be individualized.

Graves disease in childhood: a review of the options for diagnosis and treatment

While diagnosing Graves disease in childhood and adolescence does not usually present specific problems, the treatment of hyperthyroidism is still controversial. In particular, with regard to the use of radioiodine therapy, strategies vary between many European and North American pediatric endocrinology centers. After the diagnosis is made, antithyroid drug treatment with methimazole (thiamazole), carbimazole, or propylthiouracil should be performed with caution, in particular, because of severe adverse effects, such as agranulocytosis or hepatitis, that are found in up to 1% of patients. Antithyroid drug treatment should not be continued long-term, particularly since definitive remission cannot be expected in more than 30-40% of patients. In contrast, the risk of severe adverse effects is still present, and the risk of thyroid carcinoma increases with time and appears to be considerably higher than after radioiodine treatment. To a great extent, the success of surgery depends on the skills of a trained surgeon. The question of whether to perform total or subtotal thyroidectomy is yet to be resolved. Surgery should be considered in patients with a large thyroid gland (>80g), severe ophthalmopathy, and a lack of remission on antithyroid drug treatment. Success rates have increased to up to 97%, while severe adverse effects (laryngeal nerve palsy, hypoparathyroidism) occur in approximately 4% of patients. Mortality is below 0.1%. Radioiodine treatment in children >5 years of age does not appear to be associated with an increased risk of thyroid carcinoma; however, long-term data are lacking. Compared with the surgical approach, success rates are lower, particularly if low doses of radioiodine are used. In general, adverse effects are less prevalent than in patients who have undergone surgery.

[Drug treatment of immune hyperthyroidism (Basedow disease). Patient selection, long-term follow-up and prevention of recurrence]

Since theraphy of Graves' disease is not directed towards the cause of the disease, medical theraphy is still the first choice and symptomatically effective in treating hyperthyroidism. Antithyroid drugs are effective in restoring euthyroidism in >90% of the patients durning 4-6 weeks, but 30-50% of the patients experience relapse after withdrawal. Previous prospective randomized studies evaluated prognostic parameters and the use of levothyroxine for prevention of relapse of hyperthyroidism. Recent studies have addressed the period after withdrawal amd focused on the natural course of disease. The results of a recent prospective randomized and controlled multicenter study were as follows: supplementation of levothroxine does not prevent relapse of hyperthyroidism. Basal TSH (4 weeks after withdrawal of antithyroid drugs) is the best prognostic marker. Smoking and positive TSH-receptor-antibodies at the end of antithyroid theraphy are other risk factors.

Relapse of Graves' disease after successful outcome of antithyroid drug therapy: results of a prospective randomized study on the use of levothyroxine

Antithyroid drugs are effective in restoring euthyroidism in Graves' disease, but many patients experience relapse after withdrawal. Prevention of recurrence would therefore be a desirable goal. In a prospective study, patients with successful outcome of 12 to 15 months antithyroid drug therapy were stratified for risk factors and randomly assigned to receive levothyroxine in a variable thyrotropin (TSH)-suppressive dose for 2 years or no treatment. The levothyroxine group was randomized to continue or discontinue levothyroxine after 1 year. End points included relapse of overt hyperthyroidism. Of 346 patients with Graves' disease enrolled 225 were euthyroid 4 weeks after antithyroid drug withdrawal and were randomly assigned to receive levothyroxine (114 patients) or no treatment (controls, 111 patients). Of those not randomized, 39 patients showed early relapse within 4 weeks, 61 endogenous TSH suppression, 7 TSH elevation, and 14 had to be excluded. Dropout rate during the study were 13.3%. Kaplan-Meier analyses showed relapse rates to be similar in the levothyroxine group (20% after 1 year, 32% after 2 years) and the randomized controls (18%, 24%), whereas relapses were significantly more frequent in the follow-up group of patients with endogenously suppressed TSH (33%, 49%). Levothyroxine therapy did not influence TSH-receptor antibody, nor did it reduce goiter size. The best prognostic marker available was basal TSH determined 4 weeks after withdrawal of antithyroid drugs (posttreatment TSH). The study demonstrates that levothyroxine does not prevent relapse of hyperthyroidism after successful restoration of euthyroid function by antithyroid drugs and characterizes posttreatment TSH as a main prognostic marker.