A Randomized Clinical Trial Comparing 2 Levothyroxine Regimens During Ramadan Fasting in Thyroidectomized Patients.

Context: For Muslim patients on levothyroxine (L-T4) therapy, the best approach for L-T4 intake during Ramadan fasting remains unclear.

Objective: We compared 2 practical approaches for L-T4 intake during Ramadan.

Methods: We randomly assigned 69 patients (21 males, 48 females, median age 44 years) with differentiated thyroid cancer (DTC) who underwent thyroidectomy in the past and are on stable LT4 doses to 2 arms. Arm A (33 patients) ingested their pre-Ramadan L-T4 dose at the evening meal and ate immediately. Arm B (36 patients) increased their pre-Ramadan dose by 25 µg if their regular L-T4 dose was ≤150 µg/day or by 50 µg if their pre-Ramadan dose was >150 µg/day and ate immediately.

Results: At the beginning of Ramadan (baseline), the median thyrotropin (TSH) level and the numbers of patients in euthyroidism, subclinical hyperthyroidism (Shyper), or subclinical hypothyroidism (Shypo) were comparable between the 2 arms (P = .69 and P = .65, respectively). At the end of Ramadan, in arm A there were 17 (51.5%), 3 (9.1%), and 13 (39.4%) patients in euthyroidism, Shyper, and Shypo compared with 17 (47.2%), 14 (38.9%), and 5 (13.9%) patients, respectively, in arm B (P = .005). The mean ± SD TSH levels in arms A and B at the end of Ramadan were 5.6 ± 6.0 mU/L and 1.67 ± 2.6 mU/L, respectively (P = .0001).

Conclusion: No overt thyroid dysfunction developed but there were more cases of Shypo in arm A and Shyper in arm B. Arm B achieved desirable levels of TSH (normal or slightly suppressed) in 86% of cases and might be a preferable approach, especially for patients who need TSH suppression (eg, DTC).