One of the most characteristic presenting features of hyperthyroidism is weight loss, despite an increased appetite. This phenomenon is easily understandable, as hyperthyroidism is accompanied by a rise in metabolic rate, energy expenditure and thermogenesis which is clearly not matched by an increased appetite and caloric intake in the vast majority of patients. Consequently a decrease in adipose tissue and muscle results. (Curiously a small proportion of hyperthyroid patients, fewer than 10%, present with weight gain owing to an increased appetite that exceeds the rise in metabolic rate

Levitt, Naomi S

Ross, Ian Louis

South African Medical Journal

Cape Town University OpenUCT

EDITORIALto be learned from the programmatic methodologicalapproaches of the national TB control programme.Linda-Gail BekkerRobin WoodHIV Research UnitDepartment of MedicineUniversity of Cape Town1. Morcroft A, Vella S, Benfield TL, et al. Changing mortality across Europe in patients infectedwith HIV-1. Lancet 1998; 352: 1725-1730.2. Moore RD, Chaisson RE. Natural history of HIV infection in the era of combinationantiretroviral therapy. AIDS 1999; 13: 1933-1942.3. Palella FJ, Delaney KM, Moorman AC, et al. Declining morbidity and mortality amongpatients with advanced human immunodeficiency virus infection. N Engl J Med 1998; 338:853-860.4. Levi GC, Vitoria MA. Fighting against AIDS: The Brazilian experience. AIDS 2002; 16: 2373-2383.5. Farmer P, Leandre F, Mukherjee JS, et al. Community-based approaches to HIV treatment inresource-poor settings. Lancet 2001; 358: 404-409.6. Bekker L-G, Orrell C, Reader L, et al. Antiretroviral therapy in a community clinic — earlylessons from a pilot project. S Afr Med J 2003; 3: 458-462.7. World Health Organisation. Scaling up Antiretroviral Therapy in Resource-limited Settings:Guidelines for a Public Health Approach. Geneva: WHO, 2002.8. Regensberg LD, Hislop MS.  Aid for AIDS: Areport back on more than four years ofHIV/AIDS disease management in Southern Africa. Southern African Journal of HIV Medicine2003; 10: 8-10.9. Bredell Consensus Statement on the Imperative to Expand Access to Antiretroviral Medicinesfor Adults and Children with HIV/AIDS in South Africa. November 2001. NationalTreatment Congress Resource Document Number 12. Cape Town: TAC, 2001.10. Boulle A, Kenyon C, Skordis J, Wood R. Rationing HAART Part I: An exploration of the costsof a limited public sector antiretroviral treatment programme in South Africa. S Afr Med J2002; 92: 811-817.11. Joint United Nations Programme on HIV/AIDS (UNAIDS). Report on the Global HIV/AIDSEpidemic. Geneva: UNAIDS, July 2002.12. Harries AD, Nyangulu DS,  Hargreaves NJ, Kaluwa O,  Salaniponi FM. Preventingantiretroviral anarchy in sub-Saharan Africa. Lancet 2001; 358: 410-414.13. Egger M, May M, Chene G, et al. Prognosis of HIV-1-infected patients starting highly activeantiretroviral therapy: a collaborative analysis of prospective studies. Lancet 2002; 360: 119-129.14. Southern African HIV Clinicians Society. Clinical Guidelines: Antiretroviral Therapy inAdults. June 2002 version. Southern African Journal of HIV Medicine 2002; 8: 22-29.515July 2003, Vol. 93, No. 7  SAMJExcessive weight gain following therapy forhyperthyroidism — a major problemOne of the most characteristic presenting features ofhyperthyroidism is weight loss, despite an increased appetite.This phenomenon is easily understandable, as hyperthyroidismis accompanied by a rise in metabolic rate, energy expenditureand thermogenesis which is clearly not matched by anincreased appetite and caloric intake in the vast majority ofpatients.  Consequently a decrease in adipose tissue andmuscle results.  (Curiously a small proportion of hyperthyroidpatients, fewer than 10%, present with weight gain owing to anincreased appetite that exceeds the rise in metabolic rate.1)Intuitively, one might assume that restoration of thyroidhormone levels to normal would result in the return of weightto premorbid levels.  Unfortunately, the insidious presentationof hyperthyroidism, and inaccurate recall by patients,complicate a true assessment of premorbid weight.Nevertheless, just over half of the respondents to aquestionnaire sent to women treated for hyperthyroidismreported experiencing a weight problem over a mean follow-upperiod of 4 years. 2 Furthermore, numerous reports, includingthat by Brunova et al.3 in this issue of S A M J (p. 529), corro b o ratethe notion that weight gain following therapy forhyperthyroidism is frequently excessive.  A mean increase inweight of between 1.55 and 16.4 kg has been reportedfollowing anti-thyroid therapy.2-6 Indeed, patients attending ourclinic have become aware of this phenomenon, as theycommonly express concern that treating their hyperthyroidismwill lead to excessive weight gain.Brunova et al. report a retrospective analysis of 160 patientswho were treated for hyperthyroidism; 147 were treated withradioactive iodine, 3 underwent thyroidectomy and theremainder received carbimazole. Hypothyroidism ensued in86.7% of the former two groups and was treated withthyroxine.3 As the premorbid weight could not be ascertainedaccurately, the baseline weight was taken as the weight atpresentation.  Weight gain was noted for 24 months, but itstabilised thereafter.  The median weight gain found was 5 kg,6 months after definitive therapy, 9 kg after 12 months and 12kg after 24 months.  Importantly, 29% of their cohort wereoverweight at presentation (body mass index (BMI) > 25kg/m2) and 19.3% were obese (BMI > 30 kg/m2).  Two yearsafter treatment, 51.3% had become obese, representing a 32%increase in the prevalence of obesity.Notable predictors of weight gain in studies of patientstreated for hyperthyroidism have included a history of weightloss prior to diagnosis, pre-existing obesity, a diagnosis ofGraves’ disease and the development of hypothyroidism, eventransiently.5 In contrast, patient age, sex and mode of therapyhave not been predictive.2,5 Brunova et al. described similarmajor factors associated with increased weight gain, i.e. thediagnosis of Graves’ disease, need for thyroxine therapy andpoor control of thyroid function on such replacement therapy.3Yet the extent of weight gain and the rise in the prevalence ofobesity was greater than reported by others.  For example, Daleand colleagues, who also did not know patients’ premorbidweight, described a mean weight gain of 5.4 ± 0.5 kg and an18.5% prevalence of obesity.5 Possible explanations for theseJuly 2003, Vol. 93, No. 7  SAMJEDITORIAL516differences are the significantly greater proportion of patientswho were obese at baseline in the local study, which representsa major risk factor for further weight gain and a higher rate ofnon-compliance with thyroxine replacement.  A number of mechanisms have been proposed for the weightgain following treatment of hyperthyroidism.  Although it hasbeen demonstrated that food energy intake decreases oncehyperthyroidism is treated, this reduction may be insufficientrelative to the fall in metabolic rate, leading to theovershooting of the premorbid weight.4 Others have suggestedthat there is a long-term disturbance in neurochemicalregulation of appetite and weight after hyperthyroidism. 7Recently, Tigas and colleagues8 suggested that circulating tri-iodothyronine (T3) may be inadequate, when providingthyroxine (T4) alone in the form of thyroxine in patientsrendered hypothyroid following treatment ofhyperthyroidism.8 However, more research is required beforeany recommendations can be made that  T3 be replacedtogether with T4 rather than the current practice of T4replacement alone.Obesity has become a major public health problem in bothdeveloped and developing countries, and it is now recognisedas a disease with morbidity comparable to that ofhypertension.9 As clinicians we should be creating anawareness of the importance of maintaining a healthy weightin all our patients, but particularly in those most at risk ofweight gain and obesity.  Healthy food choices andperformance of regular exercise should be stressed for all.  Inorder to lessen the risk of excessive weight gain amongpatients treated for hyperthyroidism, we should ensure thathyperthyroid patients receive appropriate advice to restrictenergy intake once on treatment and thus reduce a possiblecontributor to the ranks of the obese, a method proven to be ofbenefit.10 In addition, replacement therapy with thyroxineshould be commenced timeously when hypothyroidism arises,and finally thyroid hormone levels (thyroid-stimulatinghormone and T4) should be meticulously maintained withinthe normal range.Ian Louis RossNaomi S LevittDivision of EndocrinologyDepartment of MedicineUniversity of Cape Town1. Gurney C, Hall R, Harper M, Owen SG, Roth M, Smart GA.  Newcastle thyrotoxicosis index.Lancet 1970; 2: 1275-1278.2. Jansson S, Berg G, Lindstedt G, Michanek A, Nyström E.  Overweight — a common problemamong women treated for hyperthyroidism. Postgrad Med J 1993; 69: 1070-1111.3. Brunova J, Bruna J, Joubert G, Koning M. Weight gain in patients after therapy forhyperthyrodism. S AfrMed J 2003; 93: 529-531 (this issue).4. Abid M, Billington CJ, Nuttall FQ.  Thyroid function and energy intake during weight gainfollowing treatment for hyperthyroidism. J Am Coll Nutr 1999; 2: 189-193.5. Dale J, Daykin R, Holder R, Sheppard M, Franklyn JA.  Weight gain following treatment ofhyperthyroidism. Clin Endocrinol 2001; 551: 233-239.6. Franklyn JA, Daykin J, Drolc Z, Farmer M, Sheppard MC.  Long term follow-up of treatmentof thyrotoxicosis by three different methods. Clin Endocrinol 1991; 34: 71-76.7. Morley JE.  Neuropeptide regulation of appetite and weight. Endocr Rev 1987; 8: 256-287.8. Tigas S, Idiculla J, Becket G, Toft A.  Is excessive weight gain after ablative treatment ofhyperthyroidism due to inadequate thyroid hormone therapy. Thyroid 2000; 10: 1107-1111.9. World Health Organisation. Obesity Preventing and Managing the Global Epidemic . Report of aWHO Consultation on Obesity,  Geneva 3-5 June 1997). Geneva: WHO, 10. Alton S, O’Malley BP.  Dietary intake in thyrotoxicosis before and after adequate carbimazoletherapy;  the impact of dietary advice. Clin Endocrinol 1985; 23: 517-520.

Excessive weight gain following therapy for hyperthyroidism - a major problem

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Excessive weight gain following therapy for hyperthyroidism - a major problem

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