Association of serum vitamin B(12) levels with stage of liver fibrosis and treatment outcome in patients with chronic hepatitis C virus genotype 1 infection: a retrospective study

BACKGROUND: Chronic hepatitis C (CHC) is a global health challenge. New therapeutic agents with excellent sustained virological response (SVR) rates are available mainly in developed countries, while the majority of CHC patients live in countries with low health budget. Predictors of therapeutic response are therefore necessary. Vitamin B(12) appears to be involved in hepatitis C virus replication. METHODS: We therefore studied retrospectively the relationship between baseline serum vitamin B(12) levels and clinical features in 116 CHC genotype 1 infected patients. Logistic regression models with univariate and multivariate analysis were used in the statistical analysis. RESULTS: Baseline serum vitamin B(12) levels were found to be positively associated with serum transaminase activities (AST, p = 0.002, ALT, p = 0.04), baseline viral load (p < 0.0001), stage of fibrosis (p = 0.0001) and favorable interferon-λ3/4 (IFNL3/IFNL4) rs12979860 genotypes (p = 0.04), and inversely with SVR (p < 0.001) as well as with rapid virological response (p = 0.001). Patients with baseline serum vitamin B(12) levels below a cut-off value of 570 ng/L achieved a SVR rate of 59% with an odds ratio (OR) of 13.4 [confidence interval (CI) 4.3–41.9, p < 0.0001] compared to patients above the cut-off value. By combining serum vitamin B(12) levels and IFNL3/IFNL4 rs12979860 genotypes, patients with baseline serum vitamin B(12) levels below the cut-off value of 570 ng/L and IFNL3/IFNL4 rs12979860 CC genotype achieved a SVR rate of even 80% with an OR of 54 (CI 9.9–293, p < 0.0001) compared to patients above the cut-off value and non-CC-genotypes. CONCLUSION: Our data suggest baseline serum vitamin B(12) levels as useful noninvasive marker for characterizing CHC patients. They might further help to identify responders to a standard treatment.