HCV genotype 1 subtypes (1a and 1b): similarities and differences in clinical features and therapeutic outcome

Aim: To evaluate similarities and differences in HCV-1 subtypes 1a and 1b in the presenting clinical features and the response to peg-interferon and ribavirin (Peg/RIBA).Patients and methods: A total of 1,233 naïve patients with HCV genotype-1 infection, 159 (13 %) with subtype 1a and 1,074 (87 %) with subtype 1b were treated with Peg-IFN/RIBA at 12 Italian centers. Covariates included in the logistic model were age, gender, BMI, serum alanine aminotransferase, serum gamma-glutamiltranspeptidase (γGT), platelets counts, liver fibrosis, the occurrence of type 2 diabetes, baseline viremia, and IL28B genotype.Results: At multivariate analysis, baseline characteristics differentiating patients with HCV-1a versus HCV-1b were young age, male gender, no F4 fibrosis, and no diabetes. SVR was achieved by 37 % of patients with subtype 1b and 45 % of those with subtype 1a, a nonsignificant difference of 8 % (p = 0.069). In patients with subtype 1a, predictors of SVR were IL28B CC (OR 5.78, CI 1.98–16.83), RVR (OR 4.18, CI 1.66–10.55), female gender (OR 2.83, CI 1.83–6.78), and HCVRNA (OR 0.55, CI 0.32–0.96). In patients with subtype 1b, the ranking of predictors was levels RVR (OR 6.49, CI 4.32–9.73), IL28B CC (OR 3.32, CI 2.15–4.58), γGT (OR 1.59, CI 0.14–2.22), HCVRNA (OR 0.61, CI 0.47–0.79), and age (OR 0.01, CI 0.02–0.42).Conclusion: In Italy HCV-1 subtype 1a prevails in young male patients with less advanced liver damage, findings that imply a more recent spreading of the infection with this viral strain. The two HCV-1 subtypes appear equally responsive to Peg-IFN/RIBA, with IL28B genotyping and monitoring of RVR mostly influencing the therapeutic response.