TESTING STRATEGY

Evidence Suggests Need for Expanded HCV Testing, Particularly Coupled With Opioid Screening in Young People

Current hepatitis C virus (HCV) screening strategies may not be adequate in the face of the opioid epidemic. Previous screening guidelines have focused on reaching the estimated 2.7 million persons with chronic HCV infection in the United States, the vast majority of whom were born from 1945 to 1965. Given the high prevalence in this population, both the Centers for Disease Control (CDC) and the United States Preventive Services Task Force recommend one-time testing for all persons in this birth cohort, as well as patients with known risk factors, like injection drug use.

However, new data shows that the incidence of acute infection with HCV has increased nearly three-fold between 2010 and 2015 due to increases in injection drug use as part of the opioid epidemic. It is estimated that the rate of new infections may be as high as 40,000 new infections per year, with the largest increases occurring in younger people.

To combat the rising incidence of infection, and because of the availability of new, effective treatments, there has been renewed interest in re-examining HCV testing strategies. Several new studies verify that HCV testing is often overlooked in younger, at-risk people and that universal testing of all adults may be cost-effective.

Model Shows Universal HCV Testing is Cost-Effective
Universal screening may be more cost-effective than either birth cohort screening or no screening at all, according to a study published Sept. 8 in Clinical Gastroenterology and Hepatology.  

“The incidence of hepatitis C among younger drug-injecting patients is skyrocketing so we have a blip in HCV cases that’s no longer isolated to the baby boomer cohort,” said Mark Eckman, M.D., the lead author of the modeling study, in a statement.

Eckman and colleagues estimated the cost effectiveness of universal, one-time screening for HCV infection in all adults over the age of 18 years living in the United States and to determine the prevalence of HCV antibody above which HCV testing (followed by treatment of infected patients with guideline-recommended therapy) is cost-effective. The model assumed prevalence of chronic HCV antibody positivity among adults born between 1945 and 1965 is 2.6 percent and in the non-birth cohort of 0.29 percent. Additionally, the model assumed a third generation enzyme-linked immunosorbent assay (EIA) with a sensitivity of 94 percent and a specificity of 97 percent, and a cost screening of $40.03 (HCV antibody EIA test plus level one office visit).

The researchers found that universal screening followed by guideline-based treatment of all those with chronic HCV infection has an incremental cost effectiveness ratio of $11,378 dollars per quality-adjusted life years (QALY) gained, compared with birth cohort screening alone. Not screening is more expensive and less effective than both of the screening strategies.

Universal one-time screening of the general adult U.S. population at a prevalence of HCV antibody greater than 0.07 percent cost less $50,000/QALY, the generally accepted threshold for cost-effectiveness, compared with a strategy of no screening. Compared with one-time, birth cohort screening, universal, one-time screening and treatment cost $11,378/QALY gained.

“With adoption of a policy of universal adult testing, all clinical care settings should initiate HCV testing programs,” writes Eckman and colleagues from University of Cincinnati Medical Center in Ohio. “However, realizing that resources are scarce, data regarding the cost effectiveness threshold can guide local policy decisions by directing testing services to settings where they generate sufficient benefit for the cost.”

Universal Screening in Real-World Settings
Despite several years of birth cohort screening, it is presumed many infected individuals outside of this age range remain undiagnosed, but exact estimates are lacking. Several studies presented at IDWeek 2018 (San Francisco; Oct. 3-7) showed results of universal screening in real-world emergency department settings.

Vanderbilt University Medical Center initiated a screening program in the emergency department. Adult patients who underwent clinically necessary phlebotomy were offered HCV screening. Samples were initially tested for HCV antibodies, but if positive, reflexed for HCV RNA testing.

From April 2017 through March 2018, 11,637 screening tests were performed. Of these, 8.7 percent were HCV antibody positive and 4.2 percent were RNA positive. The authors note, 81 of 1,008 HCV antibody positive samples could not undergo RNA testing due to insufficient sample volume.

While people born between 1945 and 1965 did have the highest percent of HCV antibody-positive results (11.9 percent) and HCV RNA-positive results (4.9 percent), there were a notable number of people outside of the birth cohort that were antibody or RNA positive (7.2 percent and 3.9 percent, respectively). Overall, the majority of HCV RNA positive cases (63.5 percent) were born outside of the birth cohort. Additionally, only 31.6 percent of HCV RNA-positive cases had a known history of intravenous drug use. More than one-third of HCV RNA-positive cases (36.7 percent) were both outside of the birth cohort and without a known intravenous drug use history.

“Universal screening identified many infections that would have been missed using age cohort and risk factors alone,” write the authors led by Cody A. Chastain, M.D., from Vanderbilt University in Nashville, Tenn. “Emergency department HCV screening may be a useful method to augment guideline-based testing and intervene among populations not consistently screened.”

Testing Not Happening in Younger, Opioid Users
Teens and young adults who have injected drugs are at high risk for HCV, but most aren’t tested, according to another study presented at IDWeek 2018 (San Francisco; Oct. 3-7). Further, the study authors suggest that while current guidelines recommend testing in with known injected drug use, health care providers may not be comfortable screening adolescents and young adults for opioid use disorder, thus underestimating who is at risk for HCV infection.

The researchers retrospectively identified 13- to 21-year-olds who had a least one outpatient visit at any of 98 participating U.S. Federally Qualified Health Centers from 2012 to 2017. Using electronic medical record data to evaluate the frequency of HCV testing and predictors of HCV screening.

Over the study period, 269,287 youth meeting inclusion criteria were identified (54.7 percent female; 37.6 percent White, 33.5 percent Hispanic, 17.6 percent Black). The mean age at first HCV screening was 18.5 years.

Over the study period, 2.5 percent of teens and young adults were tested for HCV and of these 2.2 percent had reactive HCV testing. Confirmatory RNA testing was conducted in 76.5 percent of patients with positive screening tests, with 55.6 percent of these having detectable RNA.

Only 35 percent (325 of 933) of patients with diagnosed opioid use disorder and 8.9 percent of patients with any diagnosed drug use were tested for HCV. Further, only 10.6 percent of individuals tested for HCV also were tested for HIV. Older age (19-21 versus 13-15 years old at study end), Black race, and a diagnosis code for substance use disorder (amphetamine, opioids, cocaine, or cannabis) were independently associated with receiving HCV testing.

“Screening for opioid use disorder and other drug use, and then testing for hepatitis C in those at high risk, can help us do a better job of eliminating this serious infection, especially now that very effective hepatitis C medications are approved for teenagers,” said lead author Rachel Epstein, M.D., from Boston Medical Center in Massachusetts, in a statement. “Even when drug use is identified, there’s a belief that youth are less likely to test positive for HCV, which isn’t necessarily the case as we show in our study. Clearly, this is an overlooked group that is at high risk.”

Takeaway: New evidence suggests that birth cohort-based HCV screening might not be adequate to capture rising rates of infection associated with the opioid epidemic.

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