Screen Time

A new study indicates age-based screening can lower hepatitis c mortality
by Larry Buhl

LifeGuide [Hep Talk]

It is well understood that early detection can prevent serious complications and death due to HCV, yet approximately three-quarters of Americans with HCV are not aware they are infected, and many will not be diagnosed until they are symptomatic—too late for effective HCV treatment.

Healthcare providers generally offer HCV testing to people thought to be at risk, including current or recent injection drug users, people who received blood transfusions before donated blood was adequately screened, and others known or suspected of exposure. The U.S. Preventive Services Task Force does not recommend screening for low-risk populations. It is estimated that this risk-based approach finds only three percent of infected individuals per year, leaving a significant number of people with undiagnosed and untreated HCV infection.

A new study presented at a recent Digestive Disease Week meeting in Chicago found that age-based screening could net significantly more HCV-infected people than the traditional risk-based model. Researchers estimated that the approach could lead to 106,000 fewer cases of advanced liver disease and 59,000 fewer HCV-related deaths and would be cost-effective to implement.

The study, titled “The Impact of Birth-Cohort Screening for Hepatitis C Virus,” was based on the understanding that chronic HCV infection typically takes years or decades to progress to severe liver disease. With that being the case, many people now developing cirrhosis or liver cancer were infected decades ago.

Lead researcher Lisa McGarry and her team used an epidemiologically-based mathematical computer model to project economic and clinical outcomes of an age-based screening program. They compared two models of targeted HCV screening based on birth year against traditional risk-based screening: the birth cohort screening model assumed that everyone born between 1946 and 1964—commonly known as the baby boomer generation—would be screened once over a five-year period, regardless of risk factors or liver disease symptoms, while another model looked at a larger “baby boomer plus” cohort of people born between 1946 and 1970. Researchers assumed that twenty-four percent of people would be treated with standard interferon-based therapy at the time of diagnosis, about one third would be ineligible for treatment, and ten percent of untreated people would start therapy each year.

Based on the results, researchers say the age-based screening model suggests:

• Among approximately 102 million people between forty and sixty-four years-old in the United States, about 1.6 million are infected with HCV but don’t know it. This birth cohort approach would screen about 79 million people versus 8 million using the risk-based approach.

• More than 1.3 million people would be diagnosed with HCV using the boomer-plus age-based screening approach, versus about 427,000 using the risk-based approach. About 472,000 would undergo HCV treatment, versus 234,000 under risk-based screening.

• About 404,000 versus 124,000, respectively, would achieve sustained virologic response, or a cure.

• Rates of liver disease outcomes would decrease with expanded screening: compensated cirrhosis would decrease to 112,991 fewer cases; decompensated cirrhosis: 52,787 fewer cases; hepatocellular carcinoma: 28,634 fewer cases; liver transplants: 5,914 fewer cases; HCV-related deaths: 47,953 fewer cases.

• Screening the “baby boomer-plus” cohort would result in approximately 106,000 fewer cases of advanced liver disease and about 59,000 fewer HCV-related deaths.

• Although age-based screening would cost more than risk-based screening ($45.1 billion versus $32.0 billion) it would reduce expenses related to advanced liver disease by more than $4 billion.

The study is the first to look at birth-cohort screening outcomes for HCV and “provides compelling evidence for putting age-based screening guidelines into practice,” said Zobair M. Younossi MD, MPT, vice president for research at Inova Health System and executive director of the Center for Liver Diseases at Inova Fairfax Hospital in Falls Church, Virginia.

Researchers also addressed the effect of new direct-acting anti-HCV drugs, which increase the cure rate when added to pegylated interferon/ribavirin. At the conference they said these new drugs would lead to even greater reductions in advanced liver disease and death if age-based screening were implemented.

In a DDW press release, McGarry called age-based screening a smart investment, comparable to widely accepted preventative health practices. “In particular, screening for HCV now may reduce future costs to Medicare.”

Researchers also say the age-based screening strategy may be more convenient for clinicians and patients tend to not want to discuss risk factors like IV drug use. However, they have not suggested that age-based screening replace risk-based screening, but rather complement it.

Funding for the study was provided in part by Vertex Pharmaceuticals, which has developed the new HCV protease inhibitor telaprevir (Incivek).

Larry Buhl is a freelance journalist and screenwriter living in Los Angeles.

August 2011