Thyroid Dysfunction in Genotype 3 Chronic Hepatitis C Patients Treated with Interferon & Ribavirin

Abstract

Purpose: IFN & RIBA therapy for CHC infection has been associated with thyroid dysfunction. Aim of our study was to determine pattern of thyroid Dysfunction only in Genotype 3 Patients and to assess risk factors and reversibility of thyroid disorders induced by IFN therapy. Methods: Patients with CHC, either biopsy proven and/or tested positive for HCV RNA by PCR and having only genotype 3 (N = 200), (M = 101, F = 99) were treated with IFN alpha 2b 3MIU TIW (N = 150) or PEG IFN alpha2a 180 Mcg (N = 50) along with weight based RIBA were included. TSH, free T3 and T4, Thyroid peroxidase antibodies, Thyroglobulin antibodies and Thyroid Stimulating Immunoglobulins were measured at 0, 3, 6, 9 and then at 12 months of treatment. Thyroid dysfunction was defined as TSH level below or above the normal range (0.2–4.5 MIU/L). Frequency was compared using chi square test with Yate's correction or Fischer exact test. A multiple logistic regression model was used in the statistical analysis of various factors for the development of thyroid dysfunction. Variables which were used included age, gender, type of IFN used, presence or absence of thyroid auto antibodies before starting therapy, impact of RVR and SVR. Type of thyroid disease and its outcome were assessed during and after therapy. Results: Thyroid dysfunction developed in 21 (10.5%) (M = 8, F = 13) of 200 patients. Hypothyroidism was seen in 17 and hyperthyroidism in 4 patients. Dysfunction occurred in 15 (10%) of 150 patients who received standard IFN as compared with 6 (12%) of 50 patients who received Peg IFN (P= 1.0). Pretreatment autoantibodies were seen in 15 of 21 patients who later on developed thyroid dysfunction while they were seen only in 10 of remaining 179 who didn' t develop thyroid disease. (P > 0.05) Amongst 200 patients who completed all 6 months of HCV treatment, overall SVR was achieved in 162 (81%) patients. While out of 21 patients who developed thyroid dysfunction SVR was seen in 16 of 21 (76%) as compared to 179 patients who didn' t have thyroid dysfunction SVR was present in 145 (81%) (P= 0.96). By multivariate analysis female gender and pre-treatment autoantibodies presence were independent predictors of developing thyroid dysfunction (P < 0.01) while age, type of IFN, RVR and SVR were not. These patients were followed for six months after cessation of IFN therapy. Out of 21 patients 19 became euthyroid during six months post IFN therapy, while only two patients had to continue taking therapy after this time period. Both were from Peg IFN group and suffered from Hypothyroidism. Conclusion: Female gender and pretreatment auto-antibodies detection are associated with thyroid dysfunction while type of IFN, age, RVR and SVR have no impact on thyroid disease development in CHC.