Thyroid Disturbance in Patients with Chronic Hepatitis C Infection: A Systematic Review and Meta-analysis

Background & Aims: The involvement of thyroid autoimmunity and dysfunction in patients with chronic hepatitis C virus (HCV) infection before interferon -a (IFN-a) therapy remains controversial. We performed this meta-analysis to evaluate the association of HCV infection with the presence of anti -thyroid antibodies and dysthyroidism. Methods: A literature search was carried out to collect articles dated up to August 2015 to identify observational studies which compared the prevalence of anti -thyroid antibodies and thyroid dysfunction in IFN-a na ve chronic HCV-infected subjects with non-HCV infected controls. Random-effect or fixed-effect meta-analyses were applied and results reported as odds ratios (ORs) with 95% confidence intervals (CIs). Results: Twelve studies were included, involving 1,735 HCV-infected and 1,868 non-HCV infected subjects. Pooled anti-thyroid antibody prevalence tended to be higher in HCV-infected subjects. The prevalence of anti-thyroglobulin antibody (TGAb), anti -thyroid peroxidase antibody (TPOAb), anti-thyroid microsomal antibody (ATMA) were 2.40-fold, 1.96 -fold and 1.86 -fold higher in HCV-infected subjects than in controls, respectively. The prevalence of hypothyroidism also differed by HCV infection status, with a pooled risk of 3.10 (95%CI: 2.19-4.40) in HCV-infected subjects. However, the results did not show a significant difference in the prevalence of hyperthyroidism between the two groups. Conclusion: Chronic HCV infection may be an independent risk factor for thyroid disturbance. It is advisable for the clinicians to monitor both thyroid antibodies and function in the course of chronic HCV infection, independent of IFN-a treatment.