Time to Euthyroidism and Its Determinants Among Thyrotoxicosis Patients on Anti-Thyroid Drug Who Attend to Medical and Ambulatory Clinics of South Tigrai General Hospitals

PURPOSE: To determine the time to euthyroidism and its determinants among thyrotoxicosis patients on anti-thyroid drug attending the medical and ambulatory clinics of South Tigrai General Hospitals, Ethiopia, 2015–2020. METHODS: A multi-center retrospective cohort study was conducted from March 30, 2020, to July 30, 2020, among adult thyrotoxicosis patients who received anti-thyroid medications in the medical and chronic ambulatory clinics of South Tigrai General Hospitals, Ethiopia. Epi-data manager version 3.1 software was used for data entry and then exported to STATA version 15 for windows for analysis. Cox proportional hazards regression model was used to determine the determinants of time to euthyroidism and the summary measures of the adjusted hazard ratio with a 95% CI were presented, and P-value < 0.05 used to declare the statistical significance. RESULTS: One hundred and seventy-five (51.9%) thyrotoxicosis patients become euthyroid with the median time to euthyroidism of 9 months, IQR (6–12) months, with a total of 5542 person-months of observation. Age greater than 40 years (AHR = 0.7; 95% CI 0.54–0.96), toxic multi-nodular goiter (AHR = 0.69; 95% CI 0.60–0.87), World Health Organization goiter size three (AHR = 0.78; 95% CI 0.54–0.82) and baseline free thyroxin (AHR = 0.96; 95% CI 0.80–0.99) were the independent determinants of delayed time to euthyroidism. CONCLUSION: The time to euthyroidism was longer than the expected time. High baseline free thyroxin, toxic multinodular goiter, elderly patients, and patients with World Health Organization goiter size three were determinants of delayed time to euthyroidism.