Q J Med 2002; 95: 57-58
© 2002 Association of Physicians
Correspondence |
Weight gain and treatment for thyrotoxicosis
Department of Medical Gerontology, Mid Western Regional Hospital & University of Limerick, Limerick, Ireland
Department of Diabetes and Endocrinology, Queen Mary's Sidcup NHS Trust, Sidcup, UK
Sir,
We would like to highlight an important and often neglected area in the treatment and management of thyrotoxicosis. It has been the observation of the authors that following treatment for thyrotoxicosis, and rendering patients euthyroid, weight gain and hence compliance with treatment can be problematic. To determine whether treatment for thyrotoxicosis is associated with excessive weight gain we performed a retrospective case report analysis.
We studied 65 patients who had completed treatment for thyrotoxicosis. Weights at presentation of the untreated disorder, and weights at treated euthyroid and 6 months post restoration of the euthyroid state were ascertained from the case notes. Weight and height prior to the onset of hyperthyroidism were ascertained by direct questioning of all patients. Mean weight changes from both premorbid and hyperthyroid states were compared with weights when the euthyroid state was restored and 6 months after (Table 1
). Patients were divided into two groups determined by their premorbid Body Mass Index (BMI): 46 patients in the normal weight group (BMI 19–25), and 19 in the overweight/obese group (BMI>26). Weight change was also compared according to the method of treatment (carbimazole alone vs. radioiodine vs. surgery).
|
Weight invariably increased with treatment, and continued to do so 6 months after restoration of the euthyroid state. The mean weight gain from hyperthyroid to 6 months post-treated euthyroid state was 7.2 kg (range -3 to 23.8 kg). Mean weight loss from premorbid to hyperthyroid states was 2.37 kg (range -4 to 13 kg). Thus overall mean weight gain from the premorbid state to 6 months post restoration of the euthyroid state was 5.34 kg (range -3 to 23.8 kg). Weight gain was greatest for those who were initially overweight/obese (mean 7.53 kg, range -3 to 23.8 kg) compared with the normal group (mean 4.38 kg, range 0.1 to 19.6 kg). Although there was an obvious increase in weight in both groups, analysis did not reveal a statistical difference between the two. Equally, there was no statistical difference between treatment modalities. Twenty-seven patients developed hypothyroidism after treatment (24 females, 3 males, 20 post-radioiodine and 7 post-surgery) and required thyroxine therapy to maintain a euthyroid state. There was no statistically difference in weight gain between those who required thyroxine (mean 5.67 kg, range -3 to 19.7 kg) and those who did not (mean 5.23 kg, range -1.3 to 15.5 kg).
These findings confirm our impression that the treatment of thyrotoxicosis is associated with excess weight gain. This weight gain would not appear to be purely the regaining of previously lost weight during the untreated hyperthyroid state. It is probably related to normalization of the previously high metabolic rate without concomitant reduction in appetite; thus as energy expenditure is reduced with restoration of the euthyroid state, the high calorie intake continues and weight increases.2
The degree of weight gain was particularly irksome to the overweight/obese group, as they had lost the most weight (mean 2.61 kg, range -3.8 to 13 kg) prior to diagnosis and treatment, and were pleased to do so. Patients may find this aspect of treatment distressing and consider it a direct side-effect of the anti-thyroid therapy. This may lead to disillusionment and altered compliance with treatment. We consider weight change to be an important yet neglected area in hyperthyroidism and its management. It may be that weight gain in restoring the euthyroid state is unavoidable, but we suggest it deserves more attention, and that early warning and dietetic advice should be an integral part of the initial treatment and subsequent follow-up of this common and important condition.
References
1. Hall R, Besser M. Fundamentals of Clinical Endocrinology, London, Churchill Livingstone, 1989:127.
2. Finer N, Sheikh S. Energy Expenditure, Intake and Appetite in Graves Disease Before and After Treatment. J Endocrinol1996; 148(suppl.):206.
CiteULike 
Connotea 
Del.icio.us What's this?
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||