ECE2019 Poster Presentations Thyroid 1 (70 abstracts)
1Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy; 2Master Program on Childhood, Adolescent and Womens Endocrine Health, University of Messina, Messina, Italy; 3Interdepartmental Program of Molecular & Clinical Endocrinology, and Womens Endocrine Health, University Hospital Policlinico G. Martino, Messina, Italy.
Fifty postmenopausal hypothyroid women (age 71.7±5.1 year) had been under replacement L-T4 therapy for 4.4±2.0 years before adding calcium carbonate (CC) (taken 12 h after L-T4). CC and tablet L-T4 were taken for the subsequent 2.3±1.1 years. Because serum TSH increased compared to L-T4 taken alone (3.33±1.0 vs 2.0±0.5 mU/l (baseline), P<0.001), with 9/50 having TSH values >4.12 mU/l, we instructed all 50 women to postpone CC after 68 h after L-T4 ingestion. This delay was unsatisfactory in the 9 women (2.88±0.37 mU/l vs 4.91±0.96 (delay of 12 h, P<0.001) and vs 2.19±0.45 mU/l (baseline, P<0.01), but it was satisfactory in the remaining 41 women (2.0±0.41 mUl vs 2.98±0.51 (delay of 12 h, P<0.001) and vs 1.90±0.40 mU/l (baseline, not significant)). Because of the relationship between TSH with blood pressure (BP), total cholesterolemia (CHOL) and fasting glycemia (FG), changes in these indices were evaluated from baseline through postponement of CC at 68 h after tablet L-T4. All indices worsened when CC was taken 12 h after L-T4 but decreased significantly when CC was taken 68 h after L-T4. However, these last values were greater than baseline, with FG significantly greater both in the 9 and 41 women. To assess whether TSH, CHOL, FG, SBP and DBP would decrease further under novel L-T4 formulations, we proposed to switch from tablet to the preferred formulation (liquid solution or softgel capsule) while maintaining the same daily dose of L-T4, timing from breakfast and 68 h delay from CC. Sixteen women (group 1) accepted (1/9 and 15/41; 9/16, liquid solution, and 7/16, capsule) while 34 women remained on tablet L-T4 and CC 68 h later (group 2). After 3 months, in group 1, TSH fell (1.23±0.49 vs 1.80±0.37, P<0.01), CHOL decreased borderline significantly (163±13 vs 171±13 mg/dl) and FG significantly (80.7±7.9 vs 83.4±6.3 mg/dl, P<0.05); SBP and DBP remained unchanged. In contrast, in group 2, TSH (2.43±0.89 vs 2.33±0.52) insignificantly increased, and all other indices increased too, DBP borderline significantly (69.7±9.0 vs 66.3±6.5 mmHg) and FG significantly (93.2±14.8 vs 89.5±14.5 mg/dl, P<0.01). Postponing the ingestion of CC by 6-8h after tablet L-T4 is not sufficient to ensure optimal levels of TSH and TSH-sensitive indices. In contrast, this goal can be achieved by either novel formulation of L-T4.