Preference, Adherence, and Maintenance of Euthyroidism Using 3 Different Regimens of Levothyroxine Intake during the Fasting Month of Ramadan

Introduction: Millions of Muslim hypothyroid patients fast during Ramadan. Limited data are available on the effect of fasting during Ramadan and different levothyroxine (L-T4) timings on thyroid status. The present study aimed to report preference, adherence, and maintenance of euthyroidism using 3 different regimens of L-T4 intake during Ramadan. Methods: This is a prospective study including Muslim hypothyroid patients fasting during Ramadan between 2018 and 2019. Patients freely chose between 3 regimens, regimen 1: to take L-T4 at sunset and postpone food and beverages for 60 min; regimen 2: to have iftar (first meal) at sunset, stop food and beverages for 3–4 h, have L-T4, and wait for 60 min before suhor (last meal); regimen 3: have suhor at midnight, stop food and beverages for 3–4 h, and have L-T4 before next fast. Thyroid status was assessed before and within 6 weeks after Ramadan. Results: 393 patients were included. The first 2 regimens or a combination of both was the most preferred by patients 40.5, 36.7, and 17%, respectively. 323/393 patients were adherent to L-T4 regimens (82.2%). 273/393 patients were euthyroid after Ramadan (69.5%). TSH pre- and post-Ramadan were 4.35 ± 12.30 mIU/L and 2.73 ± 3.37 mIU/L, respectively, with no statistically significant change ( p = 0.225). Adherence was predicted post-Ramadan euthyroidism (odds ratio [OR] 2.8 in univariate and OR 2.96 in multivariate models). Conclusions: The first and second regimens or a combination of both was preferred by most patients. High rates of adherence and post-Ramadan euthyroidism were observed. Adherence to the preferred regimen is the main determinant of post-Ramadan euthyroidism.