Endocrine Abstracts

Several levo-thyroxine (L-T₄) formulations are now available. However, scientific societies discourage the use of generic L-T₄ owing to its uncertain bioavailability in comparison with brand L-T₄. Recent literature data suggest that using a liquid formulation of brand L-T₄ improves the management of hypothyroidism. However, it is not clear whether patient satisfaction improves on liquid (LI) L-T₄, as patients may initially be reluctant to switch from their tablet (TA) formulation to a ‘new’ (LI) L-T₄. The aim of this study was to evaluate efficacy, tolerability and quality of life (QoL) changes in Hashimoto’s thyroiditis patients who began de novo L-T₄ treatment for sub-clinical or overt hypothyroidism. Patients were randomized to LI (n=15) or TA (n=16) L-T₄ formulation (IBSA Farmaceutici). After 6 months, they switched from one formulation to the other. Clinical and hormonal data were collected at the baseline and after 1 (1st titration), 6 (crossover), 7 (2nd titration) and 12 (end of study) months. Hypothyroid symptoms were scored on the Billewiciz scale (BS); subjective satisfaction and QoL were evaluated by means of a visual analogic scale (VAS) and the ThyPRO inventory. On randomization, sex distribution (85% females), median age (59 years), thyroid volume (8 ml), blood pressure (systolic 120 mmHg; diastolic 80 mmHg) heart rate (70 bpm) and concomitant therapies (1 drug on average), but not BMI (TA 26.7±1.3 kg/m², LI 22.7±0.8 kg/m²; P=0.02), were similar between groups. BS scores (LI 3.8±0.4; TA 2.7±0.4; P=0.06), fT₃, fT₄ (LI 7.7±0.7 pg/ml; TA 9.1±0.6; P=0.1) and TSH (LI 21.5±8.4 mIU/l; TA 11.0±2.5 mIU/l) were not statistically different. ThyPRO scores did not differ between groups at the baseline. In both groups, L-T₄ treatment was begun at a dosage of 50 μg/day. Before the 1st titration, sevne women (LI 27% TA 19%) withdrew their consent and dropped out. After titration, the dosages were similar in both groups (LI 46.1±4.1 μg per day, TA 55.8±3.0 μg per day). On crossover, clinical data remained unchanged between groups and BMI was still significantly lower (P=0.003) in LI (23.6±0.9 kg/m²) than in TA (26.0±1.2 kg/m²) subjects. On L-T₄ treatment, BS scores decreased in both groups (LI 2.4±0.4, TA 1.3±0.4; P=0.1). No differences were noted between groups in terms of VAS (LI 8.4±0.4, TA 8.1±0.4) or laboratory data. A reduction on all ThyPRO scales was noted in both groups. To improve median TSH levels (LI 3.6 mIU/l, TA 3.3 mIU/l) after crossover and 2nd titration, L-T₄ dosages were increased in 43% and 29% of patients on LI and TA L-T₄, respectively. Intention-to-treat analysis revealed similar median BS (LI 3, TA 2.0) and VAS (LI 8, TA 7.5) scores and median TSH (LI 6.1 mIU/l, TA 6.0 mIU/l) levels at the end of the study. After 12 months of L-T₄ treatment, 60% of subjects required a further increase in L-T₄ dosage, in both formulations, to adequately control hypothyroidism. At the end of the study, only the ThyPRO scales ‘eyes’, ‘anxiety’ and ‘cosmetic complaints’ had improved less on LI than on TA therapy. In conclusion this protocol was burdened by a high number of drop-outs; the number of data available may therefore constitute a limitation to the study. Both LI and TA L-T₄ formulations displayed similar efficacy. However, dosages need to be carefully increased when treatment for the control of hypothyroidism is started de novo. The tolerability of LI and TA L-T₄ proved similar and QoL improved in all patients on therapy.