Hepatitis C virus infection is common among patients in the ED, and risk- and birth-cohort–based screening strategies recommended by the CDC may miss approximately 25% of these cases, according to two studies published in Clinical Infectious Diseases.
“EDs serve as a medical safety net for many Americans who are also at high risk for HCV,” Yu-Hsiang Hsieh, PhD, associate professor of emergency medicine at Johns Hopkins University School of Medicine, and colleagues wrote. “Since the CDC’s revised HIV testing recommendations for the health care settings were released [in 2006], many EDs have had great success in implementing routine HIV testing to the population they serve over the past decade. This coupled with the availability of effective therapeutics makes EDs a key and strategic component of the national plan to expand HCV testing. The optimal strategy for HCV testing in ED settings remains unknown.”
CDC screening recommendation misses 25% of undetected HCV
In 2012, one-time HCV testing for all individuals born from 1945 to 1965 was recommended by the CDC alongside previous risk-based testing guidelines.
To gauge the effectiveness of this strategy and investigate the burden of undetected HCV infection, Hsieh and colleagues examined excess blood specimens collected from Johns Hopkins Hospital ED patients during an 8-week period in 2013. Sociodemographic, previous testing and diagnosis data corresponding with each sample were collected from administrative databases and electronic medical records. Researchers then tested each sample for HIV infection using third-generation HIV enzyme immunoassay (EIA) and Western blot, and HCV infection using HCV EIA. HCV RNA also was quantified for 100 randomly selected samples of HCV antibody-positive patients.
Of the 8,593 ED patients treated during the study period, 4,713 had excess blood available and were included in the analysis. These patients were predominantly female and black, and 38% were aged within the recommended range for birth-cohort testing.
Approximately 14% of examined individuals tested positive for HCV antibodies, and 31.3% of these were determined to be undocumented HCV infection (4.3% of full analysis cohort). Greater HCV prevalence was associated with male gender, black race, present HIV infection, and injection drug use. Prevalence of detectable HCV RNA in the random subset of patients with detected antibodies was 87%.
Sixty-three percent of ED patients with undocumented HCV infection were within the birth-cohort, 22% were injection drug users and 5% were known to have HIV. The researchers determined that 49% of undocumented HCV cases would be detected as a result of birth-cohort testing alone, and 26% would be diagnosed due to risk-based testing.
As such, use of these two CDC-recommended testing strategies would not have detected 25% of undocumented cases within the study cohort, the researchers wrote, and suggests that expanding upon the CDC recommendations could benefit urban EDs.
“We observed a high seroprevalence of undocumented HCV infection in our population, indicating that urban EDs could be a valuable venue for HCV testing,” Hsieh and colleagues wrote. “One-quarter of infections would still remain undiagnosed applying current ‘modified’ CDC recommendations. This suggests the need to consider revision of the CDC recommendations for HCV testing in EDs and other episodic care settings.”
EDs ‘uniquely important’ for HCV screening
Michael S. Lyons, MD, MPH, associate professor of emergency medicine at the University of Cincinnati, and colleagues demonstrated similar findings. In another recent study of HCV, Lyons and colleagues conducted a cross-sectional, observational study using a repository of patient blood samples and health histories collected at a Midwestern urban teaching hospital’s ED from 2008 to 2009. Patient health questionnaires included questions concerning sexual behavior, drug use, history of STDs and prior diagnosis of HIV and hepatitis. Samples were assayed for HCV antibody and viral RNA. The primary outcomes included HCV antibody and nucleic acid positivity prevalence.
Among the 924 participants included in the analysis, 54% were black and 50% were female. Thirty-five percent reported history of sexually transmitted infection, 6.4% reported injection drug use, 2.9% reported HIV infection and 5.2% reported HCV infection.
HCV antibodies were detected in 13.9% of the cohort (95% CI, 11.7-16.2), among which 80% also were found to be HCV RNA positive (95% CI, 73-86.6). Two cases demonstrated HCV RNA, but had no detectable antibodies. The researchers estimated that 28% of cases with antibodies and 25% of cases with replicative HCV infection would not have received screening under the CDC’s birth-cohort recommendation.
“The ED is likely to be a uniquely important venue for HCV screening, and work to overcome the logistical challenges of screening in this setting is warranted,” Lyons and colleagues wrote. “This should include not only implementation of birth cohort screening, but also screening strategies applied to an expanded age range.” – by Dave Muoio
Disclosure: Hsieh and colleagues report no relevant financial disclosures. Lyons reports investigator-initiated support from Gilead Sciences. Please see the full study for a list of all other authors’ relevant financial disclosures.