Background & objectives: The effect of vitamin D supplementation on response to antiviral therapy in hepatitis C virus (HCV) genotype 1 and 4 infection still remains unclear, with studies yielding inconsistent results. The aim of the present study was to assess the effect of vitamin D supplementation on treatment outcome in patients with genotype 1/4 chronic hepatitis C (CHC) infection.
Methods: Sixty consecutive, treatment-naïve, genotype 1 and 4 chronic HCV patients were included in the study. The patients were randomized into two groups: Vitamin D supplemented group received pegylated (PEG)-interferon α-2a 180 μg per week plus ribavirin (RBV) (1000-1200 mg/d) together with vitamin D3 (2000 IU/d) and control group received identical therapy without vitamin D (32 patients).
Results: There were no significant differences between the two groups in terms of age, sex, body mass index and baseline laboratory values. Lower vitamin D levels were associated with higher grades of fibrosis in liver histology (vitamin D >20 ng/ml - 70% vs vitamin D <20 ng/ml - 37%, P<0.05). Vitamin D supplemented group had similar rapid viral response (40 vs 28%, P=0.36), complete early viral response (53.2 vs 40%, P=0.34), end of treatment response (64 vs 46%, P=0.17) and sustained virological response (SVR) (60 vs 44%, P=0.19) as compared to control group. Interleukin 28B polymorphism [odds ratio (OR)-15.37, 95% confidence interval (CI)-2.32-101.76, P=0.04] and baseline serum vitamin D levels (OR-6.36, 95% CI-1.36-29.61 P=0.02) were independent predictors of SVR in genotype 1/4 CHC. Vitamin D supplementation was not found to be predictor of response in genotype 1/4 CHC on multivariate analysis (OR-2.79, 95% CI- 0.63-12.34, P=0.74).
Interpretation & conclusions: The present study showed that addition of vitamin D to PEG/RBV combination therapy in treatment-naïve patients who were infected with HCV genotype 1/4 had no effect on the rates of rapid, early and sustained viral responses.
Keywords: Genotype; hepatitis C interleukin 28B polymorphism; liver fibrosis; sustained virological response; vitamin D.