A meta-analysis of patients with chronic hepatitis C treated with interferon-alpha to determine the risk of autoimmune thyroiditis.

OBJECTIVE

In order to analyze the effect on autoimmune thyroiditis (AT) of current anti-hepatitis C virus (HCV) treatment in HCV-infected patients, we performed a systematic review with meta-analysis of the available literature. The present meta-analysis was conducted to evaluate the strength and the consistency of the association between treatments with interferon-alpha (IFN-alpha) for HCV infection and AT.

MATERIAL AND METHODS

A search in Medline, PubMed, and EMBASE was conducted with a systematic review of clinical studies in English and other languages. Only studies in HCV subjects compared to a control group with hepatitis B (positive HBsAg) were considered. The relative risk (RR) of AT was regarded as the most reliable outcome end-point. The pooled odds ratio (OR) and 95% confidence intervals (95% CI) were calculated from the raw study data using the Mantel-Haenszel methods. We used a statistical evaluation of heterogeneity by the chi2-test to assess whether the variation in treatment effect within trials of the same group was greater than it might be expected.

RESULTS

We identified 35 clinical trials with a total of 6.403 patients. Five trials were selected for analysis involving a total of 625 patients with hepatitis C treatment with IFN-alpha and 456 HBsAg-positive controls. These studies yielded a combined adjusted OR of 4.98 (95% IC 1.56-15.91). The test for heterogeneity was significant (P = 0.0008), and the test for overall effect was Z statistic 2.71 (P = 0.007).

CONCLUSION

Our meta-analysis indicates that treatment with IFN-alpha for HCV infection has an increased risk of AT.