Endocrine Abstracts

Background: Currently little data regarding hypothyroidism in South Africa exists, but it can be seen from international literature that a significant amount of patients, fail to reach target TSH levels.

Objectives: This observational study aimed to measure the efficacy of individually titrated doses of levothyroxine to achieve a euthyroid state.

Methods: Patients with hypothyroidism, treatment naïve and insufficiently controlled, confirmed with a laboratory TSH value, were included in the study Patients were followed-up every 7 weeks until target TSH values were achieved. Total study duration for patients not reaching target TSH levels, was 28 weeks. TSH levels, levothyroxine dose changes, compliance, concomitant medication used, weight and changes in typical disease symptoms were assessed at each visit.

Results: 290 evaluable patients were enrolled. Overall 221 (76.2%) patients reached TSH target levels of which 135 (46.6%) reached control at visit 2. 34 (11.7%) of patients were overtreated. The mean daily dosage per kg/body weight for patients achieving a euthyroid state was 1.12 μg/kg (S.D. 0.54). and the mean daily dosage 88.8 (S.D. 43.2). The most frequently used dosages in treatment naïve patients were 50 or 100 μg, whilst in pre-treated patients it were 75 and 100 μg. The 25 μg thyroxin dosage was used in 46.4% of patients and the, 12.5 μg dosage in 8.2% of patients.

Conclusions: This study highlights the need of an initial early follow-up of TSH values and continued regular monitoring until control is achieved. Potential complications of overtreatment such as osteoporosis, cardiac dysrhythmias, etc. can be devastating to patients and should be addressed amongst treating physicians. This study further highlights that a high proportion (50%) of patients required the 25 and 12.5 μg dosages for optimal titration. The mean thyroxin dosage of 1.12 μg/kg body weight in controlled patients is lower than the recommended 1.6 μg/kg.