Comparison of hepatitis C virus testing strategies: birth cohort versus elevated alanine aminotransferase levels

Abstract

Background: Hepatitis C virus (HCV) infection is unidentified in an estimated 40%-85% of infected adults. Surveillance and modeling data have found significant increases in HCV-associated morbidity and mortality.

Purpose: To compare two HCV antibody (anti-HCV) testing strategies based on (1) elevated alanine aminotransferase levels (ALT) and (2) a birth cohort approach for people born during 1945-1965.

Methods: Data from 19,055 adults aged 20-70 years who completed the National Health and Nutrition Examination Survey in 1999-2008 were analyzed in 2013. Two independent models were evaluated, based on membership in the 1945-1965 birth cohort or elevated ALT, to compare the number of identified anti-HCV-positive (anti-HCV+) individuals; proportion of total identified cases; and the number of people that would be tested using either strategy.

Results: The prevalence of anti-HCV among adults aged 20-70 years was estimated at 2.0% (95% CI=1.8%, 2.3%), representing about 3.6 million people. The birth cohort strategy would result in testing about 85.4 million people and identifying nearly 2.8 million anti-HCV+ people with a sensitivity of 76.6%. The ALT strategy would test about 21.5 million adults and identify approximately 1.8 million anti-HCV+ people with a sensitivity of 50.0%. Implementing both strategies concurrently would identify 87.3% of anti-HCV+ adults.

Conclusions: The birth cohort strategy, which is recommended by both the CDC and the U.S. Preventive Services Task Force, would identify 1 million more anti-HCV+ people than the elevated ALT approach. Concurrent implementation would identify an even larger number of individuals ever infected.

Figure 1

Participant flow and response rates, adults aged 20–70 years, NHANES 1999–2008 ^aNHANES publishes screen samples for adults aged 20–29, 30–39, 40–49, 50–59, 60–69, 70–79, and ≥80 years The screen sample for adults aged 70 years is not published by the single-year age group. Thus, we estimated the screen sample for persons aged 20–70 years based on the interview response rate for persons aged 20–69 years (76.4%; cdc.gov/nchs/nhanes/response_rates_cps.htm). ^bThe denominator used to calculate the response rate was estimated as described above. HCV, hepatitis C virus; NHANES, National Health and Nutrition Examination Survey