Urgent need for birth cohort hepatitis C testing
Posted on April 13, 2015
Study highlights urgent need to implement recent CDC and USPTF birth cohort Hepatitis C testing recommendations in the routine clinical environment
While there have been many recent notable advances in the treatment of hepatitis C, these advances can only help those individuals who are tested and identified. Unfortunately, the proportion of unidentified anti-HCV positive persons has been estimated as ranging from 40% to 85%, and it’s estimated that 45% to 60% of adults with HCV infection will go on to develop cirrhosis over the next 2 to 5 decades. The CDC in 2012, and US Preventive Services Task Force in 2013, augmented their risk factor– and medical indication–based HCV screening strategies by issuing a recommendation to test all persons born during 1945–1965 (Baby Boomers) without prior risk ascertainment. Baby Boomers account for an estimated three-quarters of all HCV infections and HCV-associated deaths in the United States.
In a retrospective US multisite study recently published in the journal Clinical Infectious Diseases, Dr. Bryce Smith and colleagues determined anti-HCV prevalence and factors associated with anti-HCV positivity between 2005 and 2010 in a large cohort of newly enrolled, previously undiagnosed adult primary care outpatients from different regions of the country (Smith BD et al. Clin Infect Dis. 2015;60 (15 April):1145-1152). This cohort was derived from a cross-sectional analysis of electronic medical record data of patients from the Birth Cohort Evaluation to Advance Screening and Testing for HCV (BEST-C) multisite retrospective cohort study.
- Study population: 209 076 newly enrolled adult patients with no previous diagnosis of anti-HCV who had a first-time encounter with a primary care outpatient service in one of four large healthcare centers (sites): Mount Sinai Medical Center (MSMC); University of Alabama at Birmingham (UAB); University of Texas, Houston (UTH); and Henry Ford Hospital System (HFH)
- Patients with documentation of HCV diagnosis at the time of first encounter were excluded
Between 2005 and 2010, 209 076 patients were observed for a median of 5 months (interquartile range, 1–23 months). The overall observed prevalence (ie, the rate of anti-HCV identification) among all patients was 0.53% (n = 1115/209 076). Calculations based on a statistical model that considers anti-HCV values for patients who were not tested revealed the following:
- The expected rate of anti-HCV identification was estimated to be 2.87% (n = 6005/209 076), with a range of 0.84% to 4.34% across the 4 sites, indicating that during the study period an estimated 81.5% (n = 4890/6005) of anti-HCV+ persons were not identified using a risk-based testing strategy
- Proportion of unidentified anti-HCV patients was estimated at 80% for new patients who had been enrolled in the health system for at least 12 months (median follow-up = 30 months)
- Proportion of unidentified anti-HCV patients was estimated at 79% for new patients who were enrolled for at least 24 months (median follow-up = 40 months)
- Among patients born between 1945 and 1965, the estimated proportion of unidentified anti- HCV+ persons was 76% (ie, observed prevalence = 1.2%; expected prevalence = 4.9%).
Among patients who were tested for anti-HCV, 6.4% (n = 1115 /17 464) were positive:
- About 75% of all anti-HCV+ persons were born during 1945–1965. This finding provides additional data in support of recommendations by the CDC and the US Preventive Task Force for HCV testing in this birth cohort and confirms previous findings of the burden of prevalence in this cohort.
- Anti-HCV positivity was significantly higher in patients born from 1945 to 1965 (13.8%) compared with the referent group of those born before 1945 or after 1965 (2.5%); blacks (12.1%) or Hispanics (8.5%) relative to whites (5.0%); widowed/divorced/separated (10.4%) or never married (6.7%) compared with married (5.0%); and males (8.8%) vs females (4.4%)
- Anti-HCV positivity was also greater in patients with a history of elevated ALT (14.9%), IDU (35.8%), hemophilia (10.7%), or HIV (17.3%).
Following multivariate adjustment in a multilevel logistic regression model, the following were identified as predictors of anti-HCV positivity among patients tested:
- History of injection drug use (consistent with the data supporting risk-based testing recommendations)
- 1945–1965 birth cohort
- Elevated ALT (consistent with the data supporting risk-based testing recommendations)
- Black race
- Hispanic ethnicity
- Never married
- Male sex
- Hemophilia and HIV-positive status were not significantly associated with anti-HCV positivity.
Testing based on risk and medical indications alone failed to identify four-fifths of previously undiagnosed adults with past exposure to HCV. Dr. Smith and colleagues conclude the following: “In the routine clinical environment, recent CDC and US Preventive Task Force recommendations to test patients born during 1945–1965 for HCV without the need for prior ascertainment of risk factors should be implemented. With the alignment of the risk-based and birth cohort testing recommendations, it is expected that identification of infected persons who were previously undiagnosed will increase, leading to higher rates of linkage to care and treatment as appropriate, or to programs that support linkage to care and treatment adherence, which would further result in reduced morbidity and mortality associated with HCV.”