Study Examines Local Hepatitis C Prevalence

A study on the prevalence of hepatitis C in Houston suggests 2.7 percent of the general population may be infected with the virus causing the disease, an estimate that more than doubles for people at high risk for sexually transmitted diseases.

The newly completed study by the Houston Department of Health and Human Services sought to determine the prevalence of infection for low- and high-risk groups in Houston. Findings from the blind, age-adjusted study augment the limited data available locally on the extent of the disease and will help the department more effectively target future education, prevention and intervention efforts.

"Studies like this enable a community to discover hepatitis C cases at earlier stages of the disease," said Dr. Raouf Arafat, the department’s Bureau of Epidemiology chief. "The cost – financial and in terms of lives lost – is much lower when hepatitis C is detected early."

Hepatitis C is a liver disease spread through contact with the blood of someone infected with the hepatitis C virus. Although not usually deadly, it has been labeled "the silent killer" because 80 percent of those infected can remain symptom free as long as 20 to 30 years despite gradual liver damage. Hepatitis C can lead to chronic liver disease and liver cancer and it is the leading cause of liver transplants.

Epidemiologists analyzed the prevalence of hepatitis C infection among low-risk populations using the medical records of a health maintenance organization, the closest measure available for the general Houston population. A targeted risk behavior survey and testing of clients served at the department’s sexually transmitted disease clinics and various community-based organizations provided the data used to assess high-risk groups.

The study found that 6 percent of people at risk for sexually transmitted diseases may be infected with hepatitis C, indicating the usefulness of screening for the disease at STD clinics. Already, public health literature has established drug treatment centers and prisons as settings with a high prevalence of hepatitis C infection; the study contributes to the theory that it is also worthwhile to target prevention efforts to other at-risk groups.

Those at risk of infection include people who have injected illegal drugs – even if it was only once and many years ago – received a blood transfusion or solid organ transplant before July 1992, or received a blood product for clotting problems produced before 1987. Others are long-term kidney dialysis patients, people with signs or symptoms of liver disease and health care workers after on-the-job exposure – such as needle sticks or splashes to the eye – to hepatitis C infected blood.

There is an extremely low chance of spreading the hepatitis C virus to a partner during sexual activity. The Centers for Disease Control and Prevention does not recommend changing the sexual practices of infected people as long as they have only one long-term steady sex partner.

Most new hepatitis C cases are spread through injection drug use. Many people with the disease became infected through blood transfusions before 1992, the year better testing of blood donors became available. Today, all blood is screened for hepatitis.

Crude estimates from the study, based on the surveyed HMO population, suggest that approximately 69,400 people currently are infected in Harris County and 40,500 people are infected in Houston. Forty-six percent of the intravenous drug users in the study were infected with the virus. CDC estimates that during the 1980s, an average of 242,000 new infections occurred each year. Since 1989, the annual number of new infections has declined by 80 percent to 36,000 by 1996. Data from the Third National Health and Nutrition Examination Survey, conducted between 1988 and 1994, indicates that an estimated 3.9 million, or 1.8 percent, of Americans have been infected with the hepatitis C virus.

The disease can prove devastating and complications may begin early in the life of an adult who is infected.

"Hepatitis C is a dangerous disease," Dr. Arafat said. "You have some patients dying in their 40s and for most this is the best time of their lives because they are beginning to settle into family life."

- A grant from the Texas Department of Health funded the study.

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