People living with HIV in the US are infrequently screened for HCV

People living with HIV are infrequently screened for hepatitis C virus (HCV) infection, according to US research published in the online edition of Clinical Infectious Diseases. The retrospective study examined screening practices at seven primary care sites between 2000 and 2011. The frequency of testing increased, but practice varied considerably between sites, and in some instances individuals with high-risk behaviours were infrequently tested for HCV.

“Screening for incidence HCV is variable across sites and improvement in frequency of screening is also variable, highlighting the a need for US-based guidelines to inform HIV practice,” write the authors.

An editorial in the same issue of the journal stresses the importance of prompt HCV diagnosis in people living with HIV.

Many people living with HIV have a high risk of infection with hepatitis C virus. Injecting drug use is a recognised risk factor for the acquisition of the HCV and there is also an epidemic of sexually transmitted HCV among gay men living with HIV in some European and US cities.

US guidelines recommend that people living with HIV at “high risk” of HCV should be considered for annual HCV antibody screening. However, the definition of high risk is unclear, and current testing practices are unknown. Because of this uncertainty, a team of investigators designed a retrospective study involving 70,000 people living with HIV who received primary care at seven sites across the US between 2000 and 2011. They measured rates of HCV screening using antibody or RNA tests on entry to care, and for people who did not have HCV at baseline, levels of subsequent testing. The factors associated with testing were also analysed, and the investigators also examined whether elevations in liver enzyme levels (ALTs) – a possible indication of recent HCV infection – triggered further diagnostic tests.

Rates of screening for people newly enrolled in care were good, with 85% undergoing HCV antibody or RNA testing within three months of establishing links with a provider. But analysis of the 9000 people who did not have HCV and who remained in care for at least one year showed that only 56% received any additional HCV screening during follow-up.

Rates of follow-up testing ranged between sites from a low of 35% to a high of 79%.

A number of risk factors and clinical characteristics were associated with HCV screening during follow-up. These included reporting unprotected anal intercourse (OR = 1.31; 95% CI, 1.08-1.59); amphetamine use (OR = 1.86; 95% CI, 1.42-2.44); having an AIDS diagnosis (OR = 1.16; 95% CI, 1.04-1.31); and a history of non-HCV-related liver disease (OR = 3.41; 95% CI, 2.51-4.63). People who reported injecting drugs were more likely to be screened than gay men or heterosexual risk groups.

Surveillance screening increased over time, and between 2008 and 2011 the rate of screening varied between 0.24 to 0.63 screens per person year. The median number of screens per person also increased at most sites, as did the proportion of people undergoing HCV testing at fixed time points.

“Surveillance screening for incident HCV infection varies substantially between clinical sites – even among those who report high-risk characteristic such as current amphetamine use and anal sex with inconsistent condom use,” note the authors.

HCV screening of people with elevations in ALTs was infrequent: only 27% of people with levels above 100 iu/l and a fifth of those with a measurement above 400 iu/ml underwent HCV antibody or RNA testing within twelve months. Screening rates were similar when analysis was restricted to gay and other men who have sex with men.

“It appears that providers in the US do not routinely use ALT as a screening test for incident HCV,” comment the investigators. They conclude national HCV screening guidelines for people living with HIV are needed, “informing whom to screen, how frequently to screen them, and what screening tests to use.”