Pegylated interferon-alpha2beta in combination with ribavirin does not aggravate thyroid dysfunction in comparison to regular interferon-alpha2beta in a hepatitis C population: meta-analysis

BACKGROUND: Interferon (IFN) has been well documented to cause thyroid dysfunction, especially in high risk patients and when combined with ribavirin (RBV). There is very sparse data to assess if pegylated IFN will further aggravate the thyroid disease risk in comparison to regular IFN. The purpose of this study was to assess the risk of developing thyroid disease with pegylated IFN (pIFN) versus regular IFN (rIFN) therapy (in combination with RBV). We also pooled our results with previous studies in a meta-analysis. METHODS: An observational study was made retrospectively of 24 patients who underwent a combination of rIFN and RBV therapy for hepatitis C virus (HCV) infection. As these patients failed to obtain an initial satisfactory response, they were retreated using pIFN and RBV. Monthly thyrotropin (TSH) levels were assessed while undergoing both treatment regimens. A meta-analysis was performed using available published data in PubMed. RESULTS: No difference in TSH levels was observed when comparing rIFN/RBV with pIFN/RBV. None of the patients developed hypo- or hyperthyroidism. TSH levels fluctuated during the treatment but did not extend outside the reference range. No further investigation was carried out in the absence of clinical and biochemical thyroid disease. The result of the meta-analysis failed to find any excess risk of thyroid dysfunction using pIFN above that of rIFN. CONCLUSIONS: The pegylation of IFN, in combination with RBV, did not aggravate thyroid diseases in the hepatitis C population. This finding is reassuring and dictates that no deviation from current practice regarding thyroid surveillance is required whilst undergoing HCV treatment.