Age- and risk-based HCV screening will leave significant proportion of infections undiagnosed

Michael Carter
Published:
13 March 2016

Screening emergency department patients for hepatitis C virus (HCV) based on birth cohort and risk profile might mean that a quarter of undiagnosed infections would remain undetected, according to United States research published in the online edition of Clinical Infectious Diseases.

Investigators from the Johns Hopkins Hospital Emergency Department, Baltimore, tested all patients attending the emergency room for HCV over an eight-week period in the summer of 2013. Approximately half of all infections detected were previously undiagnosed, and a quarter of these undiagnosed infections would have been missed had only screening protocols based on age and risk profile been applied.

“Our findings suggest that urban EDs [emergency departments] should consider expanding CDC [Centers for Disease Control] HCV testing recommendations to permit more robust identification of those patients with unknown HCV,” comment the authors.

It has been estimated that at least 2.2 to 3.2 million individuals in the United States are living with HCV infection and that the majority of these patients are unaware of their infection status. HCV prevalence is especially high in the 1945-65 birth cohort, often called the 'baby boomer' generation. Therefore in 2012 the CDC issued guidance recommending one-off HCV testing for all patients in this age group. The guidelines also recommend the screening of patients considered to be at high risk of HCV infection, including individuals with a history of injecting drug use (IDU), patients with HIV infection, and recipients of blood products.

Emergency departments are an ideal venue for the implementation of expanded HCV screening. They serve diverse populations and are often used as a healthcare safety net, therefore treating patients who do not access other medical providers. Emergency departments have also successfully implemented routine HIV screening policies.

Investigators from Johns Hopkins University Hospital wanted to see how many undiagnosed HCV infections would be picked up if all patients attending the emergency department were screened for this infection. The investigators calculated the proportion of infections detected after applying age- and risk-based screening and also the proportion that would have been missed had screening been limited to these criteria.

The hospital serves a diverse and socially disadvantaged population with high HCV and HIV infection rates. The authors therefore believe it to be an ideal venue in which to evaluate HCV screening recommendations.

All adult patients attending the emergency department with excess blood collected for clinical purposes were included in the study. Clinical data – including HCV infection status and risk – were obtained from electronic patient records.

A total of 4,713 patients were included in the study and 652 (14%) were HCV antibody positive. Approximately a third (31%) of the patients with HCV infection were previously undiagnosed.

Results supported current age-based screening guidelines. HCV prevalence was higher among the 'baby boomer' patients than other birth cohorts (25% vs. 7%; p < 0.05) and the 1945-65 birth cohort also had a higher prevalence of undiagnosed HCV infections than other age groups (7% vs. 3%; p < 0.05).

Further analysis of the undiagnosed patients showed that 49% would have been diagnosed using age-based screening and that a further 26% would have been detected with risk-based testing. However, the remaining 25% of undiagnosed patients would have left the emergency department with their HCV infection undetected had screening not been universal.

Using their eight-week data, the investigators calculated that, over a twelve-month period, 7,727 patients with HCV infection would receive care in their emergency department and that 2,419 of these individuals would be previously undiagnosed; 605 of these infections would have remained undiagnosed using existing age- and risk-based screening.

“Our results underscore the need for HCV management and treatment resources for HCV-infected individuals who frequent the emergency department,” comment the authors.

The authors recommend that all adult patients attending urban emergency departments should be screened for HCV. But they are concerned that this will place strain on HCV services. “Current workforce capacity for HCV care and treatment will unlikely be able to meet the increased demands associated with identifying known and previously undiagnosed HCV-infected individuals,” conclude the investigators. “Therefore it is imperative to prioritize and integrate strategies for HCV testing and long-term care while expanding the number of care providers with expertise in HCV care and treatment.”

Reference

Hsieh Y-H et al. Evaluation of the CDC recommendations for HCV testing in an urban emergency department. Clin Infect Dis, online edition, 2016.