Regional disparities in interferon therapy for chronic hepatitis C in Japan: A nationwide retrospective cohort study Infectious Disease epidemiology

Abstract

Background: Many patients with chronic hepatitis C have been treated with interferon (IFN) therapy in Japan, especially after the introduction of subsidies for medical expenses in 2008. However, its performance and outcome have never been evaluated. Therefore, a nationwide, mail-based, retrospective cohort study was conducted. Methods: Regional disparities in the demographic features, treatment performance, and virological response were evaluated using an intent-to-treat design. The participating prefectures were classified into nine regions from north to south (Hokkaido/Tohoku, Kanto, Shin-etsu, Hokuriku, Tokai, Kinki, Chugoku, Shikoku, and Kyushu). Multivariate logistic regression analysis was performed to select predictive factors for treatment performance and outcome. Results: From December 2009 to May 2013, 16,854 patients with chronic hepatitis C were registered from 37 prefectures in Japan (median age: 60 years; 50.4 % male; 74.8 % IFN-naïve; HCV genotype [1 or 2]/viral load [high (≥5 log IU/mL) or low (<5 log IU/mL)]: 1/high∈=∈58.2 %, 1/low∈=∈5.2 %, 2/high∈=∈27.3 %, 2/low∈=∈7.5 %; 83.4 % treated with peginterferon-α and ribavirin). Mean age, proportion of elderly patients (≥65 years), male sex, IFN-experienced, and HCV genotype were significantly different among the nine regions (all P∈