Abstract 180: Weekly dose vs daily dose in refractory hypothyroid patients with pseudo malabsorption

Background: In refractory primary hypothyroidism, even after ruling out important organic causes the resistance may persist and is called pseudo-malabsorption. If non-adherence is suspected, but not volunteered, the options to confirm the possibility are limited. We conducted this study to assess the use of Levothyroxine absorption test to diagnose pseudo-malabsorption and once weekly Levothyroxine to treat such patients Methods: This was an open labelled Randomized Control Trial with a Parallel design. All patients with age 18 or above attending Endocrinology OPD who was diagnosed with Primary Hypothyroidism but had TSH levels more than 10 mIU/L despite treatment with daily Levothyroxine at a dose of 2.5 mcg/kg/day for a period of 6 months or more were included after applying exclusion criteria after getting informed consent. Levothyroxine absorption test was done according to previously validated protocol and Absorption percentage was calculated using previously validated formula. If more than 60% it was suggestive of pseudo-malabsorption. They were randomised by simple randomization to receive oral Levothyroxine of a same standard brand either weekly once under direct supervision with a dose equal to the cumulative dose with a maximum of 14 mcg/kg (weekly dose group) or to continue to receive the same daily dose prior to randomization (daily dose group). Both groups received healthcare advice on adherence, adequate spacing and storage. Thyroid function tests were repeated at 8 weeks and at 12 weeks if not controlled at 8 weeks. Results: After randomization of 70 subjects selected after levothyroxine absorption, 40 were in the weekly once group and 30 were in the daily once group. 38 subjects in the weekly once group (95%) had controlled TFT levels by 12 weeks with 32 (80%) among them under control by 8 weeks whereas 18 subjects in the daily once group (60%) had controlled TFT levels by 12 weeks and had a statistically significant difference between the two groups (p value = 0.0005). There were no significant differences in the adverse events. 4 subjects in the weekly once group (10%) and 2 subjects in the daily once group had headache. 2 subjects in the weekly once group withdrew from the study due to headache. Conclusion: The weekly once dosage can be considered as a safe and effective option for every subject with refractory primary hypothyroidism when pseudo-malabsorption is suspected.