Weight gain in patients after therapy for hyperthyroidism

Objective. To determine the prevalence of obesity following therapy for hyperthyroidism and to assess the contributing factors associated with an undesirable weight gain.Design. A retrospective analysis was undertaken of clinical records for 160 hyperthyroid patients attending an endocrine clinic in Bloemfontein (1994 - 2001).Results. Of the 160 patients, 143 had Graves' disease and 17 patients had multinodular goitre. Most of our patients (N = 147) were treated with radioiodine, 10 patients with carbimazole and 3 patients had thyroidectomy. The median weight gain 6 months after therapy was 5.0 kg, after 12 months 9.0 kg, and after 24 months 12 kg, whereafter body mass stabilised. Before therapy 27.5% of patients had a body mass index (BMI) of < 22 kg/m2, 29.4% were overweight (BMI > 25 kg/m2) and 19.3% were obese (BMI > 30 kg/m2). Two years after treatment only 8.7% of patients had a BMI of < 22 kg/m2, 27.5% had a BMI > 25 kg/m2, and 51.3% had become obese. The main factors associated with weight gain 24 months after therapy were poor control of thyroid function on replacement therapy, diagnosis of Graves' disease and need for thyroxine replacement.Conclusion. This study has shown a large increase (32%) in the prevalence of obesity following treatment for hyperthyroidism. The main weight gain was during the first 2 years after therapy. The main factors contributing to excessive weight gain were need for replacement therapy and poor control of thyroid function

Patients treated for hyperthyroidism are at increased risk of becoming obese: findings from a large prospective secondary care cohort

YesBackground: The most commonly reported symptom of hyperthyroidism is weight loss; successful treatment increases weight. Weight gain faced by patients with hyperthyroidism is widely considered a simple reaccumulation of premorbid weight, whereas many patients feel there is a significant weight “overshoot” attributable to the treatment. We aimed to establish if weight gain seen following treatment for hyperthyroidism represents replenishment of premorbid weight or “overshoot” beyond expected regain and, if there is excessive weight gain, whether this is associated with the applied treatment modality. Methods: We calculated the risk of becoming obese (body mass index [BMI] >30 kg/m2) following treatment for hyperthyroidism by comparing BMI of 1373 patients with overt hyperthyroidism seen in a secondary care setting with the age- and sex-matched background population (Health Survey for England, 2007–2009). Next, we investigated the effect of treatment with an antithyroid drug (ATD) alone in regard to ATD with radioactive iodine (131I) therapy. We modeled the longitudinal weight data in relation to the treatment pathway to thyroid function and the need for long-term thyroxine replacement. Results: During treatment of hyperthyroidism, men gained 8.0 kg (standard deviation ±7.5) and women 5.5 kg (±6.8). At discharge, there was a significantly increased risk of obesity in male (odds ratio = 1.7 [95% confidence interval 1.3–2.2], p 10 mIU/L; 0.5 kg, 0.3–0.7, p < 0.001) or free thyroxine (fT4) was reduced (fT4 ≤ 10 pmol/L (0.8 ng/dL); 0.3 kg, 0.1–0.4, p < 0.001) during follow-up. Initiation of levothyroxine was associated with further weight gain (0.4 kg, 0.2–0.6, p < 0.001) and the predicted excess weight gain in 131I-induced hypothyroidism was 1.8 kg. Conclusions: Treatment for hyperthyroidism is associated with significant risks of becoming obese. 131I treatment and subsequent development of hypothyroidism were associated with small but significant amounts of excess weight gain compared with ATD alone. We advocate that the discussion over the weight “overshoot” risk forms part of the individualized treatment decision-making process

Radio-iodine therapy of hyperthyroid graves' disease - The Bloemfontein experience

No Abstract

Hyperthyroidism caused by TSH-producing adenoma

Objectives. To present a new case of central hyperthyroidism caused by thyrotropin (TSH)-producing adenoma.Design. Case report.Setting. Departments of Internal Medicine, Diagnostic Radiology and Biochemistry, University of the Orange"Free State, Bloemfontein.Subject and outcome measures. A 36-year-old woman with symptoms and signs of hyperthyroidism was diagnosed as having an elevated free thyroxine (T4) level and nonsuppressed THS level.Results. Magnetic resonance imaging (MRI) examination of the pituitary gland showed a macro-adenoma of the adenohypophysis, 2 x 1.5 x 1 cm in diameter. The patient did not have any other alteration in secretion of the pituitary hormones. Hyperthyroidism was successfully treated with adenomectomy. The only postoperative complication was permanent diabetes insipidus.Conclusion. THS-producing adenomas are rare but possible causes of hyperthyroidism. MRI examination helps to distinguish TSH adenoma from another form of central hyperthyroidism, namely the syndrome of pituitary resistance to thyroid hormone (PRTH)

Weight gain following treatment of hyperthyroidism - A forgotten tale

Hyperthyroidism causes weight loss in the majority, but its effect is variable and 10% of patients gain weight. Its treatment usually leads to weight gain and some studies have reported an excess weight regain. However, there is considerable inter‐individual variability and a differential effect on body weight by different treatments, with some studies reporting more weight increase with radioiodine, and perhaps surgery, compared with anti‐thyroid drugs. The excess weight regain may relate to treatment‐induced hypothyroidism. Furthermore, the transition from hyperthyroidism to euthyroidism may unmask, or exacerbate, the predisposition that some patients have towards obesity. Other risk factors commonly implicated for such weight increase include the severity of thyrotoxicosis at presentation and underlying Graves' disease. Conflicting data exist whether lean body mass or fat mass or both are increased post‐therapy and whether such increments occur concurrently or in a sequential manner; this merits clarification. In any case, clinicians need to counsel their patients regarding this issue at presentation. Limited data on the effect of dietary interventions on weight changes with treatment of hyperthyroidism are encouraging in that they cause significantly lesser weight gain compared to standard care. More research is indicated on the impact of the treatment of hyperthyroidism on various anthropometric indices and the predisposing factors for any excessive weight gain. Regarding the impact of dietary management or other weight loss interventions, there is a need for well‐designed and, ideally, controlled intervention studies