new recommendations from cdc (and adopted by US Prev Service Task Force) for hep c screening (see link: http://www.uspreventiveservicestaskforce.org/uspstf12/hepc/hepcfinalrs.htm for USPSTF recommendations and http://www.ncbi.nlm.nih.gov/books/NBK115423/ for the Agency for Health Care Research full paper). both formally released in past month or so. basically,
–common (anti-HCV Ab in 1.6% of noninstitutionalized adults), 3/4 of HCV cases in people born between 1945-1965 and peak prevalence of 4.3% in those aged 40-49. Hep C is most common indication for liver transplant, 30% of cases. also, about 1/2 of the 3-fold increase in hepatocellular carcinoma over the past few decades attributable to hep c.
–benefits of early detection: no direct evidence that screening helps. but good data that treatment leads to improved clinical outcomes
–risk assessment: major risk factor is injection drug use, or pts with hemophilia (significant percutaneous exposure) in 60-90% of cases. less significant percutaneous exposure in 10-30% (eg hemodialysis, tattoos). also sexual exposure in 1-10% (data are pretty consistent across many studies i’ve seen of discordant couples that with <10 years exposure, about 4-8% get HCV, after 10 years it goes up some to the 10-15% range). blood transfusions, esp if before 1992, is a risk factor. also, maternal-child transmission
–evaluation: HCV Ab test is best. a prior large study i saw found that using ALT levels to screen was inadequate, since about 50% of HCV positive people would be missed. about 80% of people with HCV Ab have current infection (as determined by HCV viral load)
–treatment: standard interferon treatments work and when achieve sustained viral response dramatically decrease risk of hepatocellular cancer (by 75%) and developing advanced fibrosis/cirrhosis (by 75% also)
and… there are some really impressive treatment regimens on the horizon (and seem to be getting closer to being available generally), with dramatically improved response rates and several with interferon-free regimens.
— recommendation: 1-time sceening if born between 1945-1966. more often if indicated.
for HIV screening (see http://www.uspreventiveservicestaskforce.org/uspstf13/hiv/hivsumm.htm for summary of HIV screening recommendations from USPSTF, http://www.ncbi.nlm.nih.gov/books/NBK114872/ for full report):
–high risk (men who have sex with men, injection drug use are highest risk; also people with multiple sex partners, esp with recurrent sexually transmitted infections)
–recommendation: all individuals aged 15-65 and at low risk should get a single screen. also anyone of any age with increased risk for infection and pregnant women (at each pregnancy).
–screening intervals. data not great on this. those at low risk, prob one screen sufficient. for those in high-prevalence setting (>1% seroprevalence, as in STD clinics, correctional facilities, homeless shelters, TB clinics, clinics serving MSM, and adolescent clinics with high prevalence HIV) — screen at least annually. more frequently as risk is higher
–rationale: limited data suggest that universal testing finds HIV-positive people have higher CD4 counts than with targeted screening. still more than 1/2 of HIV patients present with CD4 <350 and 75% with CD4 <500. implementing antiretroviral therapy is good for the patient (better clinical outcomes when start with higher CD4 count), and perhaps most importantly, dramatically decrease risk of HIV transmission to others
just a note of caution: we have found some HIV cases in seemingly very low-risk patients (eg, a man and wife in their 70s). the fact that one partner is low risk does not necessarily dictate that his/her partner is low-risk (ie, i think the one-time screen for low-risk is reasonable on a population basis, but we should always keep in mind the possibility of HIV even after a negative screen)
geoff