[Importance of medication adherence to peginterferon-ribavirin combination therapy in patients with chronic hepatitis C].

Background/aims: The combination therapy with peginterferon and ribavirin is a standard treatment for patients with chronic hepatitis C. However, because of the long duration of the treatment and many complications, the reduction of adherence frequently occur. This study aimed to assess influences of reduced medication adherence in the combination therapy of chronic hepatitis C patients.

Methods: We retrospectively reviewed the medical records of 82 patients with chronic hepatitis C who received a combination therapy with peginterferon and ribavirin. The patients were categorized into 3 subgroups on the basis of medication adherence. Group 1 comprised patients who received ≥80% of the recommended dosage of both peginterferon and ribavirin. Group 2 comprised those patients who received ≥80% of the recommended dosage of only 1 drug. The patients of Group 3 received <80% of the recommended dosage of both the drugs.

Results: Sustained virologic response (SVR)s of patients in Group 1, 2 and 3 were 85.4% (41/48), 85.7% (18/21), and 38.5% (5/13), respectively (p=0.002). SVRs of genotype 1 patients in Group 1, 2 and 3 were 84.2% (16/19), 75% (9/12), and 14.3% (1/7) , respectively (p=0.003). SVRs of genotype non-1 patients in Group 1, 2 and 3 were 86.2% (25/29), 100% (9/9), and 66.7% (4/6), respectively (p=0.196). Furthermore are SVRs significantly differed with the degree of medication adherence to either peginterferon or ribavirin (p=0.003 and 0.021, respectively). In multivariate analysis, the peginterferon dose was a significant independent factor associated with SVR.

Conclusions: Medication adherence of chronic hepatitis C patients to the combination therapy with peginterferon and ribavirin is very important for achieving SVR. In particular, we think that genotype 1 patients should maintain higher adherence than genotype non-1 patients.