Background/aims: Various predictive factors for peginterferon alpha and ribavirin therapy in chronic hepatitis C have been reported, but the effect of adherence to therapy has not been established. We investigated how adherence affects the sustained virologic response (SVR).
Methods: We analyzed 92 chronic hepatitis C patients receiving peginterferon alpha and ribavirin combination therapy. Patients were first identified as having either genotype 1 or genotype non-1 infection and then categorized into three groups according to their adherence to the treatment protocol: (1) patients who received >/=80% of the recommended dosage of both peginterferon alpha and ribavirin for > or =80% of the intended duration of therapy, (2) patients who received <60% of the recommended dosage of both peginterferon alpha and ribavirin for <60% of the intended duration of therapy, and (3) patients who were not included in either group 1 or 2.
Results: The rates of early virologic response, end of treatment response, and SVR differed significantly with the degree of adherence to the treatment. The SVRs of genotype 1 patients were 86.7%, 26.7%, and 66.7% in groups 1, 2, and 3, respectively (P=0.003), and those of genotype non-1 were 100%, 16.7%, and 88.9%, respectively (P<0.001).
Conclusions: Adherence to therapy is a key factor in achieving an SVR. Supportive strategies to improve adherence will increase overall SVR rates.