Longitudinal Changes in Utility Scores and Health-Related Quality of Life During Interferon-Free Direct-Acting Antiviral Therapy for Chronic Hepatitis C in Japan: Implications for Cost–Utility Analysis

Background/Objectives: Interferon-free direct-acting antiviral (DAA) therapy cures chronic hepatitis C virus (HCV) infection, but its short-term effects on health-related quality of life (HRQoL) are captured differently by generic and disease-specific instruments. We examined longitudinal changes in utility scores and HRQoL in a multicenter Japanese cohort. Methods: Adults with chronic HCV completed the EuroQol 5-Dimension 5-Level questionnaire (EQ-5D-5L), the 8-Item Short-Form Health Survey (SF-8), and the Chronic Liver Disease Questionnaire (CLDQ) at baseline and at 12, 24, and 36 weeks after treatment initiation; 48-week data were included when available. Complete-case panels were analyzed for each instrument (SF-8, n = 112; CLDQ, n = 131; EQ-5D-5L, n = 128). Domain trajectories were summarized and compared with baseline. Results: By week 36, SF-8 general health improved significantly from 50.42 to 52.47, whereas vitality (50.73 to 52.55) and mental health (51.02 to 53.05) showed nonsignificant numerical increases. CLDQ showed improvements in worry (5.21 to 5.82) and total score (5.21 to 5.47). EQ-5D-5L utility values remained high and largely stable (0.913 to 0.920), suggesting ceiling effects in patients with relatively good baseline health status. External real-world evidence also suggested better on-treatment HRQoL with ribavirin-free regimens. Conclusions: In Japanese patients with HCV, interferon-free DAA therapy was associated with early improvements in symptom-proximal and mental domains of HRQoL. Generic utility scores changed little over the short term, indicating that disease-specific patient-reported outcome (PRO) instruments and utility measures should be used together for patient-centered assessment and cost–utility modeling.