Co-infection complicates treatment efforts
In a move that may give voice to at least one key section of the "silent epidemic," infectious disease experts are recommending that HIV patients be offered testing for hepatitis C virus. The new emphasize on HCV screening was added in recent HIV recommendations because the groups have some similar risk factors (e.g., injection-drug users and patients with hemophilia).1
In addition, knowledge of HCV status is critical for management of all HIV-infected patients in order to interpret and manage elevated liver-related tests. Screening should be performed by using enzyme immunoassays (EIAs) licensed for detection of antibody to HCV (anti-HCV) in blood.
Positive anti-HCV results should be verified with additional testing (i.e., recombinant immu-noblot assay [RIBA] or reverse transcriptase-polymerase chain reaction [RT-PCR] for HCV RNA). The presence of HCV RNA in blood also might be assessed for HIV-infected persons with undetectable antibody but other evidence of chronic liver disease or when acute HCV infection is suspected.
National numbers are somewhat difficult to project, because any one HCV case can progress along several lines for years to end in benign infection or deadly liver cancer. But like a balloon payment that is finally coming due, several projections see HCV worsening over time in a large group of those previously infected. Of the estimated 4 million Americans who have HCV antibodies, about 2.7 million have active infection. Most HCV cases are believed to have been contracted before 1990, but about 30,000 new cases still occur annually.
Research indicates there was a large increase in the incidence of HCV infections from the late 1960s to the early 1980s. Annual incidence went from 45,000 infections to 380,000 infections a year in the 1980s. (See Hospital Infection Control, January, October 2000, at www.HIConline.com.)
HIV- and HCV-co-infected patients might experience HCV-associated liver disease in a shorter time course than patients infected with HCV alone and should be evaluated for chronic liver disease and the possible need for treatment. Limited data indicate that HCV treatment can be safely provided to patients co-infected with HIV and HCV.
Because the optimal means of treating co-infected patients has not been established and certain HIV-infected patients have conditions that complicate therapy (e.g., depression), this care should occur during a clinical trial or be coordinated by health care providers with experience treating both HIV and HCV infections.
People co-infected with HIV and HCV should be advised not to drink excessive amounts of alcohol. Avoiding alcohol altogether might be prudent because even occasional alcohol use may increase the incidence of cirrhosis among HCV-infected people.
In addition, patients with chronic HCV should be vaccinated against hepatitis A virus to decrease the risk for fulminant hepatitis associated with HAV. The HAV vaccine is safe for HIV-infected persons, but only about 66% to 75% of patients experience protective antibody responses. Patients should also be vaccinated for hepatitis B virus if they are susceptible.
Antiretroviral-associated liver enzyme elevations may increase among patients co-infected with HIV and HCV. Such increases might not require treatment modifications. Thus, although liver enzymes should be carefully monitored, highly active antiretroviral therapies (HAART) should not be routinely withheld from patients co-infected with HIV and HCV. However, co-infected patients initiating HAART might have an inflammatory reaction that mimics an exacerbation of underlying liver disease. In this situation, careful monitoring of liver function is required.
If the serum HCV RNA level becomes undetectable during HCV therapy and remains undetectable for six months after HCV therapy is stopped (i.e., sustained virologic response), more than 90% of HIV-uninfected patients with HCV will remain HCV RNA-negative for more than five years and have improved liver histology. For HIV- and HCV-co-infected patients, durability of treatment response and requirement for maintenance therapy are unknown.
Reference
1. U.S. Public Health Service and the Infectious Diseases Society of America. Guidelines for preventing opportunistic infections among HIV-infected persons — 2002. MMWR 2002; 51(RRO8); 1-46.
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