Endocrine Abstracts

Introduction: Graves disease (GD) is a frequent cause of primary hyperthyroidism and often presents with weight loss. Weight gain beyond the premorbid state is often reported and could be a challenge during patient’s management. Treatment modalities, disease remission and biochemical parameters at the diagnosis have been described as predictors of weight changes in patients with GD.

Objectives: To evaluate the determinants of weight changes in GD treated patients.

Methods: Retrospective, observational and longitudinal study of patients with the diagnosis of GD and at least six months of follow-up, with available data regarding baseline, premorbid and post-treatment weight. Laboratory and demographic variables, including body mass index (BMI), were also recorded.

Results: The sample included 122 patients (95 females) with a median age at the diagnosis of 48 years-old (IQR 21). Almost 34% of the patients documented some weight loss during the state of hyperthyroidism. Hyperthyroidism was responsible for a mean loss of 5,7 ± 7,8 kg, with a mean BMI reduction of 0,75 (IQR 3,00) kg/m². Moreover, patients with weight loss before treatment presented a lower premorbid BMI (22,4 ± 2,7 vs 25,1 ± 4,8 kg/m², P-value 0,027). On the other hand, after starting treatment, a weight gain was observed in 59,2% of patients, and excessive weight gain (final weight above premorbid weight) in 23,8% of them. Patients with weight gain after treatment were mainly women (78%), with a mean age of 47 ±14,7 years. These patients were also more frequently smokers (P-value 0,034) and presented higher prevalence of hypothyroidism after treatment (P-value 0,008). All patients considered underweight (BMI <18 kg/m²) presented a weight gain during treatment (P-value <0.001). Curiously, excessive weight gain was more common between individuals that did not lose weight before treatment (P-value <0.001). Hypothyroidism after treatment of GD was more prevalent among those with excessive weight gain (P-value <0.001). Finally, there was no difference in baseline TSH, TSH-receptor antibody levels, free T4 or free T3 serum levels between patients regardless of their weight changes.

Conclusions: Our analysis shows that GD patients with a lower premorbid BMI presented with a higher weight loss at the diagnosis. Also, excessive weight gain was more common between individuals that did not lose weight before treatment. These results support the evidence that other factors, especially premorbid patient’s BMI, may determine weight changes in GD patients, regardless of their analytical serum endocrinological profile and disease management.