Hepatitis C: a review for primary care physicians

Abstract

Primary care physicians see many of the estimated 250 000 Canadians chronically infected with the hepatitis C virus (HCV). Of this number, about one-third are unaware they are infected, which constitutes a large hidden epidemic. They continue to spread HCV unknowingly and cannot benefit from advances in antiviral therapy that may clear them of the virus. Many HCV-infected people remain asymptomatic, which means it is important to assess for risk factors and test patients accordingly. The third-generation enzyme immunoassay for HCV antibodies is a sensitive and specific test, although the presence of the virus can be confirmed by polymerase chain reaction testing for HCV RNA in some circumstances. Pegylated interferon-alpha and ribavirin combination therapy clears the virus in about 45%-80% of patients, depending on viral genotype. Preventive strategies and counselling recommendations are also reviewed.

Box 1

Fig. 1: Natural history of hepatitis C virus (HCV) infection. *Note that 60%–75% of patients are asymptomatic at this stage.

Fig. 2: Algorithm for testing for hepatitis C infection.,, *If the result of the anti-HCV EIA is indeterminate, a qualitative HCV RNA PCR is required. †The threshold for a positive HCV RNA assay result is > 50 IU/mL. HCV = hepatitis C virus, anti-HCV = HCV antibodies, EIA = enzyme immunoassay, ALT = alanine transferase, PCR = polymerase chain reaction.

Box 2

Fig. 3: Algorithm for hepatitis C antiviral therapy. *If the viral load drops by less than 2 logs compared with that at baseline, therapy can be stopped because the likelihood of achieving a sustained virologic response is less than 3%.,,,, †Therapy should be stopped if the virus is not cleared at 24 weeks, since sustained virologic response is very unlikely., HCV = hepatitis C virus, PEG-IFN = pegylated interferon, PCR = polymerase chain reaction.

Box 3