The Diagnosis and Management of Hepatitis C: The Role of the Physician Assistant

Abstract

Hepatitis C will pose a serious challenge to the health care system during the next 2 decades. Physician assistants can play an important role in the screening, diagnosis, and management of hepatitis C infection, and in educating patients about this disease. Screening for risk factors for hepatitis C virus (HCV) can be used to identify most infected individuals, who can then be tested for the presence of anti-HCV antibodies and HCV RNA. Hepatitis C can be treated with a combination of pegylated interferon plus ribavirin, and the virus can be cleared in a significant percentage of infected individuals. HEPATITIS C: SCOPE OF THE PROBLEM The United States faces a major public health challenge over the next 2 decades from the largely silent but widespread infection of adults by HCV. This is now the most common blood-borne infection in the United States. 1 About 2% of adults in this country are infected, but only a small fraction of these individuals have been identified and are aware of their positive viral status. 123 The Centers for Disease Control and Prevention (CDC) estimated that there were approximately 30,000 new cases of HCV infection in 2003. 4 These estimates are probably conservative, because the National Health and Nutrition Examination Survey (NHANES) data on which they were based excluded people who were incarcerated or homeless, individuals known to have high rates of HCV infection. 3,4 Chronic HCV infection is defined as the persistence of HCV RNA in the blood for at least 6 months. 2 Chronic HCV is frequently asymptomatic in its early stages, and years or decades may pass before affected individuals seek treatment. 5 Even symptomatic individuals may complain of only vague feelings of tiredness or malaise, leading to delays in diagnosis if HCV is not suspected. 5 HCV-infected patients may progress to very grave illnesses, chief among them being the occurrence of silent but progressive fibrotic liver disease. 6 The rate of progression to cirrhosis varies widely in infected patients, but it is currently estimated that up to 20% of patients infected with HCV will develop cirrhosis over a 20to 25-year period. 7 Many of these patients may progress to end-stage liver disease and death unless a transplant is performed, and HCV infection has now become the most common reason for liver transplantation in the US. 7,8 Once an HCV-infected individual develops cirrhosis, the risk of hepatocellular carcinoma is also present, contributing to mortality rates. 7 Because HCV is a systemic disease, infected patients can also develop serious extrahepatic complications of immunologic origin, including rheumatoid symptoms, kidney disease, and skin disorders. 2 If HCV-infected individuals are not identified and treated, deaths due to HCV infection are expected to increase 2to 3fold by 2010 to 2020, and annual deaths from HCV infection will exceed deaths from HIV/AIDS. 9 Physician assistants (PAs) can play important roles in identifying these individuals and helping to manage their disease, with the goal of lessening the overall health care burden and reducing the risks of mortality and morbidity from this deadly but still largely silent outbreak. HEPATITIS C: A TREATABLE DISEASE The current standard of care for HCV infection is combination therapy with pegylated interferon (IFN) alfa and ribavirin. 10 Interferons are naturally occurring proteins that have antiviral, immunomodulatory, and antiinflammatory properties. 11 Interferon alfa-2a and interferon alfa-2b have been shown to inhibit HCV replication and strengthen the host immune response to the virus. 11 Pegylated interferons are interferons that have been conjugated to inert polyethylene glycol (PEG) moieties. 11 The Diagnosis and Management of Hepatitis C: The Role of the Physician Assistant 2 of 10 Interferon alfa-2b is conjugated 1:1 to an unbranched, 12kilodalton (kd) PEG moiety to form peginterferon alfa-2b, whereas interferon alfa-2a is conjugated 1:1 to a branched, 40-kd PEG moiety to form peginterferon alfa-2a. 12 Pegylation protects the molecules from enzymatic degradation and reduces their rate of renal elimination, thereby creating more desirable, longer-acting agents. 11 The combination of pegylated interferon plus ribavirin has been shown to be more effective than either pegylated interferon monotherapy or combination therapy with standard interferon plus ribavirin in inducing a sustained virologic response (SVR), defined as the complete absence of detectable HCV RNA in serum 6 months after the end of