Endocrine Abstracts

Introduction: Treatment of primary hypothyroidism relies on a daily intake of levothyroxine, which dosage is determined first by the weight then by TSH levels monitoring. The daily dosage can vary with the cause of the hypothyroidism and the weight. The aim of our study was to determine if the adherence was a factor influencing the dosage of levothyroxine in a group of well-controlled hypothyroid patients.

Method: We performed a cross-sectional study including the patients presenting with a well-controlled primary hypothyroidism. We excluded pregnant women. We collected from their file their age, the cause of hypothyroidism, their weight, the TSH level (laboratory norms between 0.27 and 4.2µUI/ml), the duration of treatment and the current dosage of levothyroxine. We assessed for each patient the adherence to the levothyroxine with a Tunisian dialect translated version of the Girerd score. The adherence was defined as good compliance, minor noncompliance and noncompliance.

Results: We included 48 patients treated for primary hypothyroidism, with mean age of 50.4years and age varying from 19 to 37 years old. Mean duration of treatment was 10.5 years with extremes varying from two to 30years. The causes of the hypothyroidism were an auto-immune hypothyroidism in 69% of cases, thyroidectomy in 10% of cases, and iodine therapy in 21% of cases. The levothyroxine dosage ranged from 25µg to 200µg with a median of 100µg per day. TSH levels ranged from 0.29µUI/ml to 4.27µUI/ml with a median of 2µUI/ml. There was a good compliance in 19 patients (40%), a minor noncompliance in 26 patients (54,6%) and a noncompliance in 3 patients (6%). Adherence to treatment wasn’t associated with age (P=0.731) nor duration of treatment (P=0.262). By performing an ANOVA test, adherence to treatment wasn’t significantly associated with daily dosage (P=0,513) nor dose per body weight (P=0,654).

Conclusion: A lack of adherence to the treatment or to the time between the meal and the treatment is the first suspected cause of an elevation of TSH levels in a treated and well-titrated hypothyroid patient. Our study in a group of well-controlled patients showed that adherence isn’t an influencing factor for the dosage when hypothyroidism is well-controlled but should always be advised to avoid TSH rise.