The impact of hepatitis C virus outside the liver: evidence from Asia

Between 80 and 115 million people worldwide are chronically infected with hepatitis C virus, with 60%-90% of these being undiagnosed. Untreated chronic hepatitis C (CHC) is associated with progressive liver disease, cirrhosis, hepatocellular carcinoma and liver-related mortality. A number of extrahepatic manifestations are also reported in CHC patients, further adding to the burden of the disease. CHC also impacts patients in terms of lower health-related quality of life, higher levels of fatigue and reduced productivity. Furthermore, the later stages of disease are costly for both healthcare systems and society. Pegylated-interferon (PEG-IFN)+ribavirin (RBV), for many years the mainstay of treatment, leads to sustained virological response (SVR) in 40%-70% of patients. However, a substantial number of patients are ineligible for treatment, and many patients fail to achieve SVR with this regimen. Furthermore, PEG-IFN+RBV leads to impairment of patient-reported outcomes during treatment, and most patients suffer from adverse events, associated with poor adherence, treatment discontinuation and treatment failure. The approval of second-generation direct-acting antivirals (DAAs) has revolutionized the treatment of CHC patients. All-oral, PEG-IFN and RBV-free regimens have higher efficacy rates, shorter treatment durations, fewer adverse events, higher adherence rates and improvement in PROs from as early as Week 4, compared to PEG-IFN+RBV regimens. The aim of this article is to review the evidence for HCV infection as a systemic disease, summarizing the impact of hepatitis C and its treatments on clinical, patient and economic outcomes, with a focus on data from Asia and Japan specifically.