ObjectiveTo investigate the prevalence of thyroid dysfunction (TD) and IgG subclasses of thyroid autoantibodies (TAs) and to determine the predictive factors of TD in chronic hepatitis C (CHC) patients.DesignThree hundred and twelve untreated hepatitis C virus-infected patients without a history of TD or treatment with thyroid hormones were enrolled in a cross-sectional study. Clinical and biological factors were statistically analyzed to determine the correlation between TD and this patient population.ResultsThe incidence of TD was 12.5% in CHC patients. Clinical hypothyroidism (5.8%) and subclinical hypothyroidism (3.8%) were more frequent than clinical hyperthyroidism (1.6%) and subclinical hyperthyroidism (1.3%). The percentage of TA-positive patients was significantly higher in people >60 years than in those ≤60 years (31.9 vs 18.6%; P=0.042). Positive thyroid peroxidase antibody (TPOAb) was more frequent, and alanine aminotransferase (ALT) levels were lower in patients who displayed TD (TPOAb: 62.1 vs 10.8%, P=0.000; ALT: 43.5 vs 51 IU/l, P=0.046). The positive percentage of TPOAb IgG2 subclass in the TD group was significantly higher than that of patients without TD (66.7 vs 16.7%, P=0.005). Multiple logistic regression analysis indicated that only TPOAb IgG2 subclass positivity was an independent risk factor for TD in CHC patients (odds ratio=8; 95% CI: 1.225–52.246; P=0.030).ConclusionsTPOAb IgG2 subclass positivity is a risk factor for TD in CHC patients before antiviral treatment. IgG2 subclass of TPOAb might play an important role in the presence of TD in CHC patients.
High body mass index is an independent risk factor for nonresponse to antiviral treatment in chronic hepatitis C
