[Evaluation of the treatment with L-thyroxine: lack of correspondence between objectives and results]

Hypothyroidism and nodular goiter are two frequent endocrine diseases which respectively require substitutive and suppressive treatment with L-Thyroxine. Objective of this work was to evaluate the correspondence between expected and obtained TSH values in patients affected with hypothyroidism and nodular goiter submitted to L-Thyroxine treatment.

a questionnaire addressed to patients on L-Thyroxine has been available in consulting rooms of 12 family doctors of Lecce County (Italy) for a 6 month period. A hundred-twelve patients answered the questionnaire: 44 were on suppressive treatment for uni/multinodular goiter (group 1) and 68 were on substitutive treatment for hypothyroidism (group 2).

TSH dosage had been performed since less than 1 year in 91% of group 1 patients and in 87% of group 2 patients (p = ns), in group 1, 25% of TSH values were < 0.3 microU/ml, 68.2% between 0.3 and 4.5 microU/ml, 6.8% > 4.5 microU/ml (p < 0.001); in group 2, 25% of TSH values was < 0.3 microU/ml, 63.3% between 0.3 and 4.5 microU/ml, 11.8% > 4.5 microU/ml: (p < 0.001). The distribution of TSH values between the two groups was not significantly different. In patients on suppressive treatment TSH was suppressed in a number of patients significantly less in respect to the ones with not suppressed TSH value: 11 vs 33; p < 0.01; in patients on substitutive treatment the number of those ones with TSH values in between the normal range was not different from patients with TSH values above or below the normal range: 43 vs 25; p = ns. Considering the two groups together, in 52% of patients TSH was not correspondent to therapeutical objectives.

Inspite of regular checks of thyroid function, proper TSH values were achieved only in half of patients.