[Thyroid dysfunction in patients with chronic hepatitis C pre and post treatment with interferon]

The aim of this study was to evaluate the thyroid function and the dysfunction after interferon therapy in patients with chronic hepatitis C.

Between 1988 and 1994, 119 patients with chronic hepatitis C treated with interferon were reviewed 92 patients received interferon alfa for six or twelve months. 27 patients were treated with interferon beta for six months. Before, during and after interferon therapy, free thyroxine, thyroid-stimulating hormone, antimicrosomal antibodies and antithyroglobulin antibodies were measured in 51 patients. None of the patients had abnormal thyroid function or autoimmune disease before treatment.

Among the interferon-treated patients, 6% developed biochemical evidence of thyroid dysfunction during or after therapy. Most cases had hypothyroidism. Thyroid dysfunction was statistically more frequent in the female sex, older patients and in patients who received greater total dose of interferon. In one patient the titters of antimicrosomal thyroid antibodies increased from 1/10 to 1/40 and another patient was positive in a dilution of 1/80 by the time of onset of thyroid disease. Thyroid disease (hypothyroidism) developed in (3.5%) of untreated patients with chronic hepatitis C.

Interferon therapy can development autoimmune thyroid fenomena. Thyroid dysfunction and the presence of antithyroid antibodies before therapy can be a contraindication to the use of interferon in these patients. It is important that patients undergoing interferon therapy be tested for antithyroid antibodies and thyroid function before treatment and be monitored during the course of therapy. Also, it is important to evaluate the factors related with the development of thyroid dysfunction (age, sex, interferon dose...).