Normalization of thyroid function tests among thyrotoxicosis patients attending a University Hospital in North-West Ethiopia

Thyrotoxicosis is a clinical state that results from inappropriately high thyroid hormone action in tissues. Although it is one of the common endocrine disorders, there is scarcity of data on the management of thyrotoxicosis in Africa, particularly in Ethiopia. The aim of this study was to investigate treatment outcomes and determinants of treatment outcomes among hyperthyroid patients on antithyroid drugs attending a teaching hospital in Ethiopia.

A retrospective cohort study was conducted on medical records of patients with thyrotoxicosis who had attended the medical inpatient ward and chronic ambulatory clinic of the University of Gondar Comprehensive Specialized Hospital in Ethiopia between June 2013 and April 2018. Descriptive statistics were used to summarize socio-demographic and other baseline information. A cox regression method was used to determine factors associated with normalization of thyroid function tests (TFTs). All statistical tests were performed using STATA version 14.

Data from a total 211 patients were eventually analyzed. The mean age of the patients was 47.25 ± 14.26 years with female majority (94.31%). The most common etiology was toxic multinodular goiter (54.90%). Because methimazole or carbimazole are not easily available locally, all of the patients included in this study were taking propylthiouracil (PTU). Nearly 9 out of 10 patients (90.38%) had symptom resolution within a mean period of 5.37 (± 6.59) months. Sixty-two (29.81%) and 122 (58.65%) patients achieved normalization of TSH and FT4, respectively during the study period. The mean time to normalization of TSH and FT4 was 13 (±13.28) and 11.53 (±13.39) months, respectively. On the other hand, T3 and all three TFTs were normalized only among 79 (38.16%) and 55 (26.32%) patients, respectively. Older age and higher baseline FT4 levels were shown to modestly reduce the chances of achieving normalization of TSH.

Though PTU is not the preferred antithyroid agent in the management of thyrotoxicosis, all patients used PTU for the management of hyperthyroidism. All TFTs were normalized in only less than one-third of the participants. Resolution of symptoms took longer period of time than expected.