Long-term follow-up after antithyroid drug treatment withdrawal in patients with the first episode of graves` disease: a retrospective cohort study in spain

Diego Meneses; Lechuga Begona Sanchez; Romero Maria Velez; Poyatos Roberto Sierra; Martinez Clotilde Vazquez; Salas Jersy Cardenas

doi:10.1530/endoabs.92.PS2-15-09

Background: Despite a high relapse rate, antithyroid drugs (ATDs) remain the first-line therapy of Graves’ disease (GD). Long-term follow-up studies of GD in Spain are scarce. Our aims were to identify clinical differences between patients who relapsed vs those who attained remission and to describe the relapse rate of GD after ATD withdrawal.

Methods: We analyzed patients with the first episode of GD who were treated with ATDs during 2010 - 2020, in a third-level hospital in Madrid, Spain. Relapse was defined as overt clinical and biochemical hyperthyroidism after the withdrawal of ATDs. Categorical and continuous variables were analyzed by chi-squared test and independent samples t-test. ROC analyses were used to determine relapse cutoff values for each of the quantitative variables. The cumulative risk of relapse during follow-up was estimated using the Kaplan–Meier approach.


		Remission	Relapse
Numbers		168	105
Male sex, n (%)	32 (11.7)	25 (14.5)	7 (6.7)	0.040*
Age at diagnosis, years	46.1 (36.4 – 53.9)	45.6 (36.4 – 51.9)	46.8 (36.9 – 56.4)	0.379
Thyroid volume, mL	13.6 (8.8 – 19.5)	13.6 (8.8 – 19.7)	13.2 (8.8 – 18.9)	0.709
fT4, ng/dL	2.47 (1.83 – 3.46)	2.45 (1.72 – 3.64)	2.5 (1.9 – 3.2)	0.501
fT3, pg/mL	6.75 (4.77 – 10.57)	6.76 (4.54 – 10.52)	6.48 (5.1 – 10.7)	0.707
TRAb, U/l	5.60 (3.16 – 11.3)	4.97 (3.08 – 10.21)	6.6 (3.61 – 12.9)	0.393
Graves’ orbitopathy, No. (%)	37 (13.7)	16 (9.7)	21 (20)	0.016*
Smoking, No. (%)	44 (18.7)	26 (17.8)	18 (20.7)	0.035*
Treatment duration, months	18.4 (14.6 – 22.9)	17.9 (13 – 21.8)	19.4 (16.8 – 23.5)	0.043*

Results: During a median follow-up time of 4.2 years (1.2 – 6.8), 105 (38.5%) patients experienced a relapse. Fifty-four (51.4%) relapses occurred during the 1^st year, 20 (19%) during the 2^nd, 11 (10.5%) during the 3^rd, 9 (8.6%) during the 4^th and the remaining 11 (10.5%) during the following 6 years. The majority of relapses occurred during the first and second year, 0.0172 relapses per patient-month and 0.0074 relapses per patient-month, respectively. Cutoff values to predict relapse were fT4 ≥2.5 ng/dl, fT3 ≥5.07 pg/ml, TRAb ≥ 6.33 U/l, age ≥ 50.1 years and a thyroid volume of ≥ 27.7ml for males and ≥ 12.2 for females.

Conclusions: In our population, female sex, Graves` orbitopathy and smoking were associated with relapse of GD. The majority of relapses occurred during the first 2 years but maintained a considerable rate until the 4^th year after ATD withdrawal.

Endocrine Abstracts

PS2-15-09