FRI527 Timing Of Thyroxine Dose During Ramadan: A Randomized Controlled Trial

Disclosure: R.M. Alamoudi: None. S.M. Nawar: None. H.S. Alharbi: None. A.A. Al Qarni: None. A. Alzahrani: None. A.K. Almulla: None. W.T. Busaad: None. N.F. Alahmari: None. N.D. Alshamrani: None. L. Alkhalifa: None. Y.M. Saleh: None. M. Ramadan: None. A. Borai: None. Background: The effect of Ramadan fasting on the thyroid profile, and the best time for L-thyroxine (LT4) intake in relation to fasting during Ramadan remains undetermined. Objectives: To compare two different time points of taking LT4 therapy during fasting the month of Ramadan in regards to thyroid profile and patient satisfaction. Methods: A multicenter open-label randomized controlled trial. Patients with primary hypothyroidism were recruited from three centers in three cities in Saudi Arabia (Jeddah, Riyadh, and Alhasa). Patients with thyroid cancer were excluded. TSH and FreeT4 (FT4) were measured two weeks before Ramadan, and four to six weeks after Ramadan. Results: 303 patients with primary hypothyroidism were randomized; 156 to take the LT4 dose at sunset with sips of water at the time of breaking fast and wait 30-60 minutes to eat the main Iftar meal (pre-Iftar), and 147 to take the LT4 dose just before the start of fasting (pre-dawn) regardless of their last meal intake. There were no significant differences between the two groups in demographics or comorbidities. The mean age was 49 ±12 years, 87% were female, and the average duration of hypothyroidism was 9.7 ±8.25 years. The mean weekly LT4 dose in the pre-Iftar vs. pre-dawn group was 753.3 ±349.4 vs. 733.2 ±265.6 mcg, p=0.001, and the Pre-Ramadan thyroid profile was: TSH 2.56 ±2.16 vs. 2.46 ±1.72 mIU/L, p=0.3, FT4 13.45 ±2.1 vs 13.08 ±2.4 pmol/L, p=0.16. Post-Ramadan thyroid profile values were: TSH 3.64 ± 4.1 vs. 4.07 ±4.17 mIU/L, p=0.78, FT4 12.96 ±0.1 vs. 12.64 ±0.22 pmol/L, p=0.003. The estimated difference within the group means post-Ramadan was - 0.41 ±0.51 mIU/L, p=0.43 for TSH, and 0.32 ±0.28 pmol/L, p=0.24 for FT4. Generalized linear model repeated measures analysis of variance showed no significant difference over time in TSH or FT4 within or between groups (p = 0.47 vs. 0.81). Patient compliance and satisfaction with the regimens were similar between groups. Conclusion: There is no significant change nor difference in thyroid profile between the two regimens related to the change in LT4 intake during the fasting months of Ramadan. Both regimens can be utilized depending on patient preferences. ClinicalTrials.gov: NCT05421468. Saudi FDA: SCTR # 22041002 Presentation: Friday, June 16, 2023