Evaluation of Acute Hepatitis C Infection Surveillance --- United States, 2008

Hepatitis C virus (HCV) infection affects nearly 4 million persons and causes an estimated 12,000 deaths each year in the United States (1). For the 10-year period from 2010 to 2019, the direct medical cost of chronic HCV infection is projected to exceed $10.7 billion, the societal cost of premature mortality attributed to HCV infection is projected to be $54.2 billion, and the cost of morbidity from disability associated with HCV infection is projected to be $21.3 billion (2). The Institute of Medicine recently recommended a comprehensive evaluation of the national hepatitis B and C surveillance system (3). Complete and timely surveillance data are essential for early identification and response to outbreaks and for implementation of evidence-based prevention strategies. To assess these attributes, CDC compared acute hepatitis C surveillance data reported in 2008 from the National Notifiable Diseases Surveillance System (NNDSS) and the Emerging Infections Program (EIP), which conducts enhanced surveillance for acute hepatitis C in selected states. This report summarizes the results of that analysis, which indicated that 26 (22%) of 120 cases reported from EIP-funded sites were missing from NNDSS. Data on race and major HCV risk factors were missing from 22% and 60% of reports in NNDSS, compared with 8% and 25% of reports in EIP, respectively. The mean duration between diagnosis and reporting of the case to the state health department was 30 days (range: 0--298 days) in NNDSS compared with 19 days (range: 0--350 days) in EIP sites. These findings underscore that enhanced surveillance for acute hepatitis C improves the completeness and timeliness of the data.

Reporting of Acute Hepatitis C Cases Through NNDSS

Health-care providers, hospitals, and laboratories are required to send reports of cases of HCV infection to state and local health departments that include them within their jurisdiction. Reports meeting the Council of State and Territorial Epidemiologists (CSTE) and CDC case definition for acute hepatitis C* are entered into each state's notifiable disease surveillance system. States voluntarily transmit case reports to CDC on a weekly basis via the National Electronic Telecommunications System for Surveillance (NETSS).† NETSS is a system of computerized record formats used to transmit NNDSS data from health departments to CDC. The NETSS case reporting form includes data on demographics (e.g., age, date of birth, sex, race, and ethnicity), clinical information (e.g., date of onset, date of diagnosis, jaundice, hospitalization, and death), and risk factor exposures occurring 6 weeks to 6 months before illness onset (e.g., injection-drug use, sexual/household contact with a person with hepatitis, blood transfusion with dates of transfusion, dialysis, needle stick, tattoo, surgery, acupuncture, and being a health-care worker who has contact with human blood). Laboratory results are not transmitted to CDC because the electronic infrastructure in NETSS does not include fields for laboratory findings.

Reporting of Acute Hepatitis C Cases Through EIP Sites

EIP hepatitis surveillance§ collects more extensive information compared with NETSS. In addition to demographics, the EIP form includes clinical data (e.g., date of diagnosis, symptoms, jaundice, hospitalization, pregnancy, death from hepatitis, liver function tests, hepatitis laboratory test results, and reason for testing) and risk factor exposures occurring 2 weeks to 6 months before illness onset (i.e., contact with a person with hepatitis and the type of contact, number of male and female sex partners, previous history of treatment for sexually transmitted diseases, use of illicit drugs [both injection and noninjection], hemodialysis, injury with sharp object contaminated with blood, blood/blood products transfusion with dates of transfusion, receipt of intravenous infusions and/or injections in outpatient settings, exposure to blood, medical/dental/public safety worker employment with frequency of exposure to blood, presence of tattoo/piercing and location where they were performed, dental work/surgery, hospitalization, residence in a long-term--care facility, and incarceration). In 2008, six EIP sites (Connecticut, Colorado, Minnesota, Oregon, 34 counties in New York State, and New York City) were funded by CDC to conduct enhanced acute hepatitis C surveillance. The catchment area of these sites comprises approximately 28 million persons. Site staff members investigate physician and laboratory reports submitted to health departments and directly contact the health-care providers to complete the demographic, clinical, and risk factor information listed in the EIP case reporting form; reports that fulfill the acute HCV infection case definition are sent monthly to CDC.

Comparison of NNDSS and EIP Surveillance

Cases reported to NNDSS and EIP were matched by a common case identifier and date of birth. CDC evaluated data quality by measuring the completeness of information on demographic and clinical variables, including age, sex, race, ethnicity, jaundice, and major HCV infection risk factors, in both NNDSS and EIP systems. Sensitivity and positive predictive value of NNDSS for reporting acute hepatitis C cases were calculated for the sites conducting both NNDSS and EIP surveillance by using EIP sites' surveillance as the reference. Timeliness of case reporting was based on calculating the interval between the date of diagnosis and the date of reporting of the case to the state health department.

In 2008, a total of 877 cases of acute hepatitis C were reported to CDC by NNDSS via NETSS from 40 states. A total of 120 cases were reported from the six EIP sites; in comparison, 102 cases were reported from NNDSS in states that also are funded for EIP. Although age and sex data were nearly complete in NNDSS and EIP sites, race and ethnicity were missing in 22% and 41% of reports in NNDSS, compared with 8% and 21% in EIP, respectively. Completeness of demographic information for cases of acute hepatitis C in NNDSS was substantially higher in the six sites that also have an EIP surveillance system in place, compared with the remaining states that are not funded for enhanced surveillance (Table 1). Presence or absence of jaundice was reported in 63% of cases from NNDSS and 98% of cases reported from EIP. Completeness of information on major HCV infection risk factors ranged from 15% to 46% for NNDSS, compared with 70% to 77% in EIP sites. Completeness of clinical and risk factor indicators did not differ substantially in NNDSS when comparing states that have EIP surveillance to those that are not part of EIP.

Comparison of the cases that were reported from NNDSS and in the six sites funded for EIP surveillance revealed that 26 cases reported in EIP were missing from NNDSS; however, only eight cases that were reported to NNDSS were not reported to EIP (Table 2). Considering EIP as the reference, sensitivity and positive predictive value of NNDSS were 78% (94 of 120) and 92% (94 of 102), respectively.

Complete information on both the date of acute hepatitis C diagnosis and date of case reporting to the state health department was available for 39 cases (4%) in NNDSS and 72 cases (60%) in EIP sites. The mean duration between diagnosis and reporting of the cases to the state health department was 30 days (range: 0--298 days) in NNDSS, with 74% and 77% of the cases being reported within 7 days and 1 month of diagnosis, respectively. Among EIP sites, the mean duration between diagnosis and reporting of the cases to the state health department was 19 days (range: 0--350 days), with 80% and 94% of the cases being reported within 7 days and 1 month of diagnosis, respectively.

Reported by

RM Klevens, DDS, Div of Viral Hepatitis, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention; RA Tohme, MD, EIS Officer, CDC.

Editorial Note

The findings in this report show that the quality of data from NNDSS is not on par with data reported from EIP surveillance sites. Clinical and risk factor information for a substantial proportion of the cases was missing from NNDSS. As shown in previous studies, NNDSS had a substantial proportion of cases with missing data on race and ethnicity (4,5). Hepatitis C disproportionately affects non-Hispanic blacks compared with persons of other races (1). Therefore, surveillance data should include race and ethnicity information to reduce disparities through targeted prevention programs (4). In addition, because of limited resources, several states are not able to handle the volume of laboratory case reports received, which affects timeliness of reporting. In 2009, a total of 27 jurisdictions had backlogs of HCV data, with an average of 6,200 reports that needed to be entered (3). Accurate, timely, and complete surveillance data are needed to identify and respond to outbreaks in a timely fashion, to guide and evaluate prevention strategies, and to allow for the early initiation of treatment, leading to an ultimate decrease in health-care costs.

Health departments using EIP enhanced surveillance have shown its effectiveness in identifying clusters or outbreaks of hepatitis C infection. For example, the New York State Department of Health detected a cluster of 20 hepatitis C infections among young injection-drug users by conducting enhanced surveillance of HCV infections reported among persons aged <30 years (6). Similarly, EIP enhanced surveillance of acute hepatitis C infections allowed the identification of health-care--associated acute hepatitis C outbreaks.

Early identification of acute hepatitis C infection is essential to prevent chronic infections and subsequent liver cancer and associated health-care costs. In fact, early treatment of hepatitis C prevents chronic disease in more than 90% of persons treated during the acute phase of the infection (7,8) and more than doubles the chance of achieving a sustained virologic response (absence of HCV RNA 24 weeks after discontinuation of therapy reflecting absence of viremia and normal liver function), compared with that achievable by treating chronic hepatitis C infection (9). The rate of achieving a sustained virologic response is inversely associated with time from acute HCV infection diagnosis (9). In addition, early treatment contributes to lower health-care costs compared with later treatment (8).

The findings in this report are subject to at least four limitations. First, the data for timeliness calculation were missing from the majority of NNDSS cases, and this might have led to an overestimation of timeliness in NNDSS. Second, estimates of timeliness would have been improved if CDC had been able to assess the duration between diagnosis and reporting to the local rather than the state health department. However, this information was not available from NETSS. Third, the states where enhanced reporting of acute hepatitis C was implemented were not selected at random; consequently, the observed differences between the performances of the NNDSS and EIP surveillance systems might not all be attributable to differences between the surveillance systems themselves. Finally, this report could not assess the proportion of missed diagnoses of acute HCV infections at the provider level, which would contribute to underreporting of cases to both NNDSS and EIP.

The comparison of NNDSS (a passive surveillance system) with EIP (an enhanced surveillance system) indicates that accuracy and timeliness of reporting for acute HCV infections were improved through enhanced surveillance. Expanding enhanced surveillance for acute hepatitis C to the national level would detect an estimated additional 22% of acute hepatitis C cases. However, because of budget constraints, enhanced surveillance for acute HCV infections is not implemented nationwide.

The Institute of Medicine report recommended a surveillance system comparable to that of human immunodeficiency virus (HIV) surveillance (3). HCV and HIV infections are similar in that many of the cases are asymptomatic and early identification and initiation of treatment would prevent transmission, complications, and deaths. However, although HIV case ascertainment requires a single laboratory test, ascertainment of a single case of acute HCV infection requires an average of four laboratory reports (10). Based on the findings described in this report, additional resources for acute hepatitis C surveillance could enhance substantially the quality of the data on which prevention interventions are based, and in turn, could reduce morbidity and mortality associated with HCV infection. Nonetheless, a cost-benefit analysis to assess the usefulness of implementing EIP enhanced surveillance for acute hepatitis C at the national level is needed.

Acknowledgments

This report is based, in part, on contributions by state and territorial health departments and EIP sites conducting enhanced hepatitis surveillance.

References

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3. Institute of Medicine. Hepatitis and liver cancer: a national strategy for prevention and control of hepatitis B and C. Colvin HM, Mitchell, AE, eds. Washington, DC: National Academies Press; 2010.
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7. Jaeckel E, Cornberg M, Wedemeyer H, et al. Treatment of acute hepatitis C with interferon alfa-2b. N Engl J Med 2001;345:1452--7.
8. Dintsios CM, Haverkamp A, Wiegand J, et al. Economic evaluation of early monotherapy versus delayed monotherapy or combination therapy in patients with acute hepatitis C in Germany. Eur J Gastroenterol Hepatol 2010;22:278--88.
9. Corey KE, Mendez-Navarro J, Gorospe EC, Zheng H, Chung RT. Early treatment improves outcomes in acute hepatitis C virus infection: a meta-analysis. J Viral Hepatitis 2010;17:201--7.
10. Klevens RM, Miller J, Vonderwahl C, Speers S, et al. Population-based surveillance for hepatitis C virus, United States, 2006--2007. Emerg Infect Dis 2009;15:1499--502.

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