Background & aims: The effects of interferon therapy in chronic hepatitis C patients on survival are unclear. Our objective was to analyze survival among a large cohort of chronic hepatitis C patients.
Methods: We used a retrospective cohort study design in the setting of 7 university hospitals and 1 regional core hospital in Japan. Our study included 2889 patients with histological-proven chronic hepatitis C: 2430 patients received interferon therapy, and 459 patients were untreated. For intervention, the median dose and duration of interferon administration was 480 million units and 137 days, respectively. For measurements, survival status was confirmed by medical records or direct questionnaires. The effect of interferon therapy on survival was assessed by standardized mortality ratio (SMR) based on published mortality among the Japanese general population and by risk ratio calculated by proportional hazards regression.
Results: Thirty of 459 untreated patients, 7 of 817 virologic sustained responders, and 49 of 1613 nonresponders died in 5.4-years follow-up. Fifty-eight (67%) of 86 patient deaths were due to liver diseases (39 to hepatocellular carcinoma). Compared with the general population, overall mortality was high among untreated patients (SMR: 1.9; CI: 1.3-2.8) but not among interferon-treated patients (SMR: 0.9; CI: 0.7-1.1). The risk of death was reduced, compared with untreated patients, among interferon-treated patients (risk ratio for overall death: 0.367; CI: 0.236-0.596; for liver-related death: 0.284; CI: 0.164-0.494) and among sustained responders (risk ratios: 0.148; CI: 0.064-0.343 and 0.050; CI: 0.012-0.216). The risk of liver-unrelated deaths remained unchanged.
Conclusions: Interferon therapy improved survival of chronic hepatitis C patients by preventing liver-related deaths.