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Studies Find Risk-based Testing Misses Many People with Hepatitis C

Testing for hepatitis C virus (HCV) in primary care settings according to risk factors may fail to identify 80% of people positive for HCV antibodies, according to a report in the January 16 edition of Clinical Infectious Diseases. A related study found that a substantial number of Baby Boomers seen in an Alabama emergency department had undiagnosed chronic HCV infection.

The CDC and U.S. Preventive Services Task Force recommend that everyone born between 1945 and 1965 should undergo HCV testing at least once, regardless of risk. This age cohort has a substantially higher hepatitis C prevalence than the general U.S. population, accounting for some 80% of all cases.

Prior to these guidelines, HCV testing was usually done on the basis of risk factors, especially a history of injection drug use or receiving a blood transfusion before donated blood was screened starting in 1992. But not all HCV risk factors -- including sexual transmission -- are fully understood and many people with hepatitis C do not know how they got it.

Primary Care Testing

Bryce Smith and Anthony Yartel from the Centers for Disease Control and Prevention (CDC) and colleagues evaluated HCV antibody prevalence and predictors of being HCV positive among previously undiagnosed adults seen in outpatient primary care facilities.

This retrospective analysis looked at electronic medical record data from 4 sites. It included a total of 209,076 adult patients (age >18 years) without a prior hepatitis C diagnosis who used at least 1 outpatient primary care service between 2005 and 2010. Participants were followed for a median of 5 months.

Results

• 17,464 patients (8.4%) were tested for HCV antibodies.
• Out of this group 115 people (6.4%) were HCV antibody positive (anti-HCV+).
• The following factors were independently associated with being HCV positive:

o   History of injection drug use -- adjusted odds ratio (OR) 6.3, or more than 6-fold higher risk;

o   Being born between 1945 and 1965 -- adjusted OR 4.4;

o   Elevated alanine aminotransferase liver enzyme levels -- adjusted OR 4.8.

• 81.5% of patients who tested HCV positive were unidentified using risk-based testing.

"In these outpatient primary care settings, risk-based testing may have missed 4 of 5 newly enrolled patients who are anti-HCV+," the study authors concluded. "Without knowing their status, unidentified anti-HCV+ persons cannot receive further clinical evaluation or antiviral treatment, and are unlikely to benefit from secondary prevention recommendations to limit disease progression and mortality."

At the recent AASLD Liver Meeting in Boston, Yartel reported that age cohort HCV screening identified 4 times as many people as prevailing screening protocols and could be "feasibly implemented."

Emergency Department Screening

In a related study published in the January 28 edition of Hepatology, James Galbraith and colleagues from the University of Alabama at Birmingham School of Medicine looked for unrecognized chronic HCV infection among Baby Boomers seen in their emergency department (ED).

The center implemented integrated opt-out HCV antibody screening of medically stable adults born between 1945 and 1965. This analysis included patients seen at the ED over the course of 11 weeks between September and November 2013. HCV antibody testing was done 24 hours per day and positive test results were confirmed using polymerase chain reaction (PCR) for HCV RNA. The primary outcome was prevalence of unrecognized HCV infection.

Results

• Out of 2325 previously undiagnosed Baby Boomers seen at the ED, 289 (12.7%) opted out of HCV screening, leaving 1529 individuals who received HCV antibody tests.
• Within the tested group, 170 people (11.1%) were HCV antibody positive, or reactive.
• Among the reactive patients, 150 people (88.2%) underwent follow-up PCR was testing.
• Among those with PCR tests, 102 patients (68.0%) were confirmed to be HCV RNA positive, indicating active infection.
• Some patient characteristics were significantly associated with being HCV antibody positive:

o   Male compared to female sex (14.7% vs 7.4% positive);

o   African Americans compared to whites (13.3% vs 8.8%);

o   Uninsured or underinsured patients compared to insured patients (16.8%-16.9% vs 5.0%).

• 100 out of 102 patients with confirmed positive HCV RNA tests received services from a linkage-to-care coordinator:

o   54 patients (54%) were successfully contacted by phone, within 5 call-back attempts;

o   38 patients (70.4%) had confirmed initial follow-up appointments;

o   21 patients (55.3%) attended their initial visit with a liver specialist, while 3 (7.9%) were still awaiting scheduled appointments.

"We observed high prevalence of unrecognized chronic HCV infection in this series of Baby Boomers presenting to the ED, highlighting the ED as an important venue for high-impact HCV screening and linkage to care," the researchers concluded.

Approximately 1 in 9 patients seen at the ED had previously unrecognized HCV [antibody] reactivity -- a seroprevalence nearly 4 times higher than previous estimates for Baby Boomers in the U.S., they noted.

Emergency department HCV testing could potentially play an important role in getting more individuals with hepatitis C diagnosed and into care, as that is the only place many people -- especially men -- come into contact with the health care system.

2/11/15

References

BD Smith, AK Yartel, H Krauskopf, et al. Hepatitis C Virus Antibody Positivity and Predictors Among Previously Undiagnosed Adult Primary Care Outpatients: Cross-Sectional Analysis of a Multisite Retrospective Cohort Study. Clinical Infectious Diseases. January 16, 2015 (Epub ahead of print).

JW Galbraith, RA Franco, JP Donnelly, et al. Unrecognized Chronic Hepatitis C Virus Infection Among Baby Boomers in the Emergency Department. Hepatology. January 28, 2015 (Epub ahead of print).2/11/15

References

BD Smith, AK Yartel, H Krauskopf, et al. Hepatitis C Virus Antibody Positivity and Predictors Among Previously Undiagnosed Adult Primary Care Outpatients: Cross-Sectional Analysis of a Multisite Retrospective Cohort Study. Clinical Infectious Diseases. January 16, 2015 (Epub ahead of print).

JW Galbraith, RA Franco, JP Donnelly, et al. Unrecognized Chronic Hepatitis C Virus Infection Among Baby Boomers in the Emergency Department. Hepatology. January 28, 2015 (Epub ahead of print).