Characteristics of Persons with Chronic Hepatitis B --- San Francisco, California, 2006

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Chronic hepatitis B is the most common cause of cirrhosis and liver cancer worldwide. Approximately 45% of the world's population lives in regions where chronic hepatitis B virus (HBV) infection is endemic, including most of Asia and the Pacific Islands, Africa, and the Middle East (1). Nearly one fourth of the population of San Francisco was born in Asia and the Pacific Islands.* In 2006, the San Francisco Department of Public Health (SFDPH) received reports consistent with probable chronic HBV infection for 2,238 persons. To characterize persons with reported confirmed chronic HBV infection in San Francisco in 2006, SFDPH collected additional data on a subset of 567 cases reported to the SFDPH chronic hepatitis B registry. Eighty-four percent of the persons were Asians/Pacific Islanders (A/PIs), 80% of whom were foreign born. Fewer than half had been referred to a gastroenterologist/hepatologist for evaluation at the time of reporting. Persons with chronic HBV infection can benefit from medical care by providers with expertise in viral hepatitis. In addition, close contacts of infected persons should be screened and offered vaccination if found to be susceptible to HBV infection. Culturally appropriate counseling for and follow-up of persons with chronic HBV infection and their contacts could help reduce the transmission of HBV infection.

Hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg), HBV DNA, and immunoglobulin M antibody to hepatitis B core antigen (IgM anti-HBc) are detectable during acute HBV infection. The presence of HBsAg, HBeAg, or HBV DNA for more than 6 months is evidence of chronic infection. The California Code of Regulations requires laboratories to report all positive test results for HBsAg to local health departments. Health-care providers also are required to report cases of acute and chronic hepatitis B. Reporting requirements for both laboratories and providers include supplying the name, age, sex, and contact information of persons with positive tests and the contact information for the associated health-care provider, although not all reports contain this information. SFDPH has maintained a registry of persons with positive HBsAg test results reported to SFDPH since 1984; the registry contains HBsAg test results for approximately 25,700 persons. Based on the standard case definitions approved by state epidemiologists for 2007, a confirmed case of chronic HBV infection is defined as an infection in a person who tests HBsAg positive, HBV DNA positive, or HBeAg positive two times at least 6 months apart.^§ A probable case is defined as an infection in a person with a single HBsAg-positive, HBV-DNA-positive, or HBeAg-positive laboratory result with either a negative IgM anti-HBc or no IgM anti-HBc test reported.

To further characterize persons with known chronic HBV infection, in January 2006, SFDPH began requesting data from health-care providers on persons who met the case definition for confirmed HBV infection for whom a second positive HBsAg result was reported to SFDPH during 2006. SFDPH formed an advisory panel of clinicians from public, private, and academic settings, who provided input into the development of the supplemental data collection form and endorsed the activity in a letter mailed by SFDPH to local health-care providers. SFDPH faxed supplemental data forms to the providers who had ordered the most recent positive HBsAg test, requesting information on patient race/ethnicity, primary language, reasons for HBsAg testing, risk factors for HBV infection, referral for specialist care, and treatment history. Providers used information obtained from a chart review or during patient visits to complete the form. Providers who did not respond were sent faxes two more times and then contacted by telephone one time.

During 2006, SFDPH received reports of 2,238 persons with test results consistent with probable chronic HBV infection; all were reported by laboratories. Of these, 1,156 (52%) were male, and 1,090 (49%) were aged 30--49 years (Table 1). Among the 714 women of childbearing age (i.e., aged 12--45 years) for whom a positive HBsAg test result was reported to SFDPH, 170 (24%) were pregnant when follow-up was conducted by the perinatal hepatitis B coordinator.

Of the 2,238 positive HBsAg reports received by the registry in 2006, a total of 1,162 (52%) met the case definition for confirmed chronic HBV infection. Of these, 736 had available health-care provider contact information. Supplemental data forms were faxed to these providers; 567 forms were returned to SFDPH with at least partial information. Of persons for whom place of birth was reported, 84% were foreign born (Table 2); of persons for whom both race/ethnicity and place of birth were reported, 80% were foreign-born A/PIs. Cantonese Chinese was reported to be the primary language of 52% of persons. Reasons for HBsAg testing included screening (43%), follow-up of a history of hepatitis B (41%), or evaluation of abnormal liver enzymes (9%). The most frequently reported risk for HBV infection was birth in an HBV-endemic region (74%); male-to-male sexual contact accounted for 12% (Table 2). A total of 21% of persons were reported to have been treated for chronic HBV infection, and 32% were reported to have been referred to a gastroenterologist/hepatologist at the time of reporting.

Reported by: S Huang, MD, S Shallow, MPH, D Stier, MD, P Shiono, PhD, A Nishimura, MPH, I Bihl, San Francisco Dept of Public Health. S Bialek, MD, I Williams, PhD, Div of Viral Hepatitis, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, CDC.

Editorial Note:

The findings in this report suggest that, in 2006, nearly 85% of persons with confirmed chronic HBV infection in San Francisco were A/PIs, 80% of whom were born outside the United States. These persons likely acquired their infections in their countries of origin, countries where HBV infection is endemic and infections usually are acquired at birth or during early childhood. Of persons who acquire chronic HBV infection when they are aged <5 years, an estimated 15%--40% will eventually have chronic liver disease, including cirrhosis and liver cancer (2). Treatment for chronic hepatitis B is increasingly effective and can prevent or slow the development of these sequelae (2). However, fewer than one third of persons with chronic HBV infection in San Francisco in 2006 had been referred to a specialist for evaluation or undergone treatment at the time of reporting.

Persons from countries where HBV infection is endemic might be unaware of their increased risk for hepatitis-B--related liver disease (3,4). Hepatitis B screening programs in A/PI communities in the United States can be an effective means of identifying persons with chronic HBV infection and encouraging them to seek medical care (5--7).

Health departments and large health systems can use electronic disease registries to characterize and provide services for persons with chronic HBV infection and their close contacts. Persons with chronic HBV infection should receive referrals for appropriate medical care, which can include treatment for HBV infection. Their close contacts should undergo screening for HBV infection and, if found to be susceptible, should receive hepatitis B vaccination. Registries also can provide local population-based data on the epidemiology of chronic HBV infection.

At least five factors are critical to ensuring that registry data are representative and complete. First, legally mandated laboratory reporting of test results is essential for complete ascertainment of cases. Second, electronic information systems are needed to promote efficiency, allowing the registry to receive data securely, account for duplicate case reports, and merge data from multiple reporting sources. Third, collaboration with laboratories is needed so that health departments can obtain additional patient demographic information and clinician contact information through laboratory reports. Fourth, communication with and timely feedback of surveillance data to clinicians are needed to increase cooperation with health departments that are requesting supplemental information on cases. Finally, because the majority of infected persons and their contacts might not speak English as their primary language, multilingual staff and culturally appropriate health education materials are needed to support these activities.

The findings in this report are subject to at least three limitations. First, the results are limited to persons who received medical care, who were tested for chronic HBV infection, and whose laboratory results or diagnoses were reported to SFPDH. Therefore, these findings do not represent the actual number of persons with chronic HBV infection in San Francisco, especially among those who do not have regular access to medical care. Second, persons included in the analysis of confirmed cases were limited to those for whom provider contact information was available. Although the California Code of Regulations mandates reporting of provider name and contact information for all notifiable diseases and conditions, this information is not reported frequently. Finally, the findings are based on data collected from persons with confirmed chronic HBV infection. Because the case definition for confirmed cases requires additional laboratory testing, the 567 persons described in this analysis might represent a subset of patients with greater access to care or those who were more likely to have undergone follow-up and treatment.

During 2007, local organizations in San Francisco are planning low-cost, community-based HBV screening and vaccination activities targeted to A/PIs and educational outreach to promote awareness of HBV screening, prevention, and treatment guidelines (http://www.sfhepbfree.org). SFDPH plans to provide persons newly reported to the registry with information on how to reduce the risk for transmission to others and the need for medical monitoring. SFDPH also will explore different approaches to identifying persons who are household and sex contacts of infected persons to inform them of their potential exposure to HBV, to recommend testing and vaccination, and to better understand the barriers to obtaining HBV preventive services.

With proper resources, chronic hepatitis B registries can help health departments characterize the burden of chronic HBV infection. Such registries also enable health departments and health-care providers to link HBV-infected persons and their contacts with recommended prevention and care services.

This report is based on contributions by L Afu-Li and S Rose, MPH, San Francisco Dept of Public Health; N Bzowej, MD, L Johnson, MD, M Khalili, MD, A Li, MD, K Man, MD, K Shafer, PhD, J Sun, MD, N Terrault, MD, and H Yu, MD, San Francisco Chronic Viral Hepatitis Registry Advisory Panel; reporting laboratories; and San Francisco clinicians.

References

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