Endocrine Abstracts

Interferon therapy for chronic hepatitis C infection has been associated with thyroid abnormalities. We sought to characterise the incidence of this in a cohort of treated hepatitis C patients receiving weekly pegylated interferon therapy in a tertiary Hepatology unit. Patients were scheduled to receive 24 or 48 weeks treatment with monthly thyroid function tests (TFTs). Data was collected from electronic treatment records of 154 consecutive patients and analysed by a single investigator. One patient was excluded due to inadequate data.

Of the 153 patients (median age 44 years {range 24 to 74 years}, 42 {27.5%} female, 111 {72.5%} male), 15 (9.8%) had abnormal thyroid function. Two patients had subclinical hyperthyroidism, 2 hyperthyroidism, 2 hypothyroidism, 4 hyperthyroidism followed an average of 8.8 weeks later by hypothyroidism and 5 had subclinical hyperthyroidism followed by hypothyroidism in average 8 weeks. Their mean age was 42.1±11.6 years, not different from those with normal TFTs (43.5±10.4 years, P=0.63). Eight (53.3%) were female and 7 (46.7%) were male as compared to 34 (24.6%) female and 104 (75.4%) male patients in the remaining 138 (P=0.018). Four patients had abnormal TFTs (low TSH with normal T4) prior to treatment with 1 consequently developing hyperthyroidism, 1 subclinical hyperthyroidism and 2 no abnormality. One patient received interferon treatment for 12 (therapy ongoing), 6 for 24 and 8 for more than 24 weeks with mean duration to onset of thyroid abnormality being 17.5±6.4 weeks (range 11 to 36 weeks). All but one patient developed their thyroid abnormality before 24 weeks treatment. One hyperthyroid patient was treated with carbimazole (for 37 weeks) and 9 hypothyroid patients needed thyroxine. Discontinuation from interferon therapy, secondary to thyroid abnormality, was not required in any patient.

In conclusion, a small but significant number of patients with hepatitis C undergoing treatment with interferon develop thyroid abnormalities and thus require regular screening of thyroid function.