Objective: To investigate viral relapse and the associated risk factors during a long-term follow-up study of chronic hepatitis C (CHC) patients who achieved end-of-treatment response (ETR) after interferon and ribavirin therapy.
Methods: This retrospective study was conducted on 146 CHC patients treated with a combination of ribavirin and pegylated (PEG) interferon-alpha (IFNa) (n=126) or conventional IFNa (n=20) for 24 (hepatitis C virus (HCV) non-genotype 1b) or 48 (HCV genotype 1b) weeks. The main outcome measure was serum HCV RNA load. The risk factors analyzed included age, sex, HCV genotype, baseline HCV RNA load, and IFN type.
Results: The mean follow-up time for all patients was 33.45+/-16.41 months (range: 12-85 months). The cumulative relapse rate during follow-up was 14.80%. The relapse rate within six months (8.90%) was significantly higher than other periods during two years of follow-up, and no relapse occurred after 30 months. Of all relapsers (n=20), 65% occurred within six months, followed by 35% within 7-24 months after antiviral therapy. The relapse rates in patients with HCV genotype 1b and non-1b were not significantly different (20.37% vs. 12.12%, X2 =1.517, P=0.315). The mean baseline HCV RNA load was significantly higher in the relapsers than that in the non-relapsers (t=0.915, P=0.362). Relapse rates were similar in patients treated with PEG-IFNa-2b, PEG-IFNa-2a and IFNa (12.12% vs. 13.97% vs. 15.00%, respectively; X2=0.104, p=0.949). The mean age of relapsers was significantly higher than that of non-relapsers (P less than 0.005).
Conclusion: The maximum probability of relapse for CHC patients exists within six months from when ETR is achieved by interferon and ribavirin therapy. A lower risk for relapse persists past this period. Thus, ETR CHC patients, especially older patients, should be carefully monitored during the two years after cessation of antiviral therapy. Standard antiviral therapy based on HCV genotype eliminates the influence of viral factors on treatment-response.