Thyroid gland dysfunctions during antiviral therapy of chronic hepatitis C

The aim of this study was assessment of the frequency of thyroid dysfunctions (TD) during antiviral treatment of chronic hepatitis C (CHC).

Data obtained from 120 not treated before patients with CHC, confirmed by the liver biopsy, and with the correct initial thyroid function, was analyzed. 63 patients were treated with IFN-alpha, and 57 with IFN + ribavirin combined therapy. HCV genotype was determined in 80 patients, and alleles HLA DRB1 in 74. Both tests were carried out by the use of commercial assay InnoLipa (Innogenetics, Belgium). All the patients had TSH level regularly monitored every 4 weeks. If any abnormalities were observed, the whole set of tests was applied for diagnosis. Frequency of TD was analyzed according to patients' sex, therapy scheme, HCV genotype and HLA DBR1 alleles. Both groups, with TD and without TD were compared by the initial data, such as: patients' sex, age, ALT activity, and liver biopsy results.

TD occurred in 40 patients (33.3%): in 7 (5.8%) signs of hypothyroidism, and in 33 (27.5%) hyperthyroidism. In 14 patients (11.7%) autoimmunological thyroiditis was diagnosed, in 2 (1.7%) subacute thyroiditis, and in the rest of patients only temporary changes in TSH concentration, without any clinical manifestations, were observed. In 4 women, the antiviral treatment was withdrawn, because of thyreotoxicosis, and in 6 patients thyroid hormones supplementation was needed after termination of interferon application. Thyroid complications occurred significantly more often in women than in men. No significant differences according to the age, therapy scheme, ALT activity, fibrosis stage, nor HCV genotype were find in the TD frequency. Among 13 genotyped DRB1 alleles, differences were observed only in DRB*11 allele frequency: in 37.7% of patients with TD, and in 9.1% of patients without TD (p = 0.0093; Pc = 0.12).

Antiviral treatment induces more often latent and transient thyroid dysfunctions as well as autoimmunological, and subacute thyroidis. The last mentioned complication may be the indication for withdrawal of the treatment, or may cause persistent hypothyroidism. Regular monitoring of TSH concentration, in 4-weeks intervals, seems to be essential for early diagnosis of thyroid complications.