Population-Based Hepatitis C Surveillance and Treatment in a National Managed Care Organization

Published Online: April 01, 2004
Deborah Shatin, PhD; Stephanie D. Schech, MPH; Keyur Patel, MD; and John G. McHutchison, MD

Objectives: To use a national population-based automated claims database to study the testing rate, prevalence, and prescribing patterns for chronic hepatitis C.

Study Design: A retrospective descriptive study that analyzes medical and pharmacy automated claims from affiliated health plans in 4 regions of the United States.

Methods: Data were collected from 11 UnitedHealth Group–affiliated health plans (3.9 million members) from January 1, 1997, to December 31, 1999. Medical claims were used to identify persons tested for hepatitis C virus (HCV). Persons with chronic HCV were identified through medical and pharmacy claims. Patterns of drug use and treatment were analyzed, including prescribing physician specialty and proportion of patients receiving baseline and follow-up testing.

Results: Of 27 871 members tested for HCV (0.7%), 1869 (6.7%) were diagnosed as having chronic HCV. Tested patients were more likely to be female (odds ratio [OR], 1.1) and older (≥25 years; OR, 4.1). Of 3259 patients with HCV, most were male (OR, 1.8) and older (≥25 years; OR, 32.0). Of these patients, 33.6% (n = 670) of men and 25.2% (n = 319) of women received treatment. Combination therapy users were more likely to undergo baseline (OR, 4.8) and follow-up (OR, 6.2) testing compared with interferon alfa monotherapy users.

Conclusions: Of the total population, 0.7% were tested for HCV, of whom 6.7% were diagnosed as having chronic HCV. Although women were more likely to undergo testing, prevalence and therapy rates for chronic HCV were higher in men. Most patients did not receive recommended baseline and follow-up testing, and the approximate 30% therapy rate suggested that many patients with HCV remain untreated.

(Am J Manag Care. 2004;10:250-256)

During the past 2 decades, hepatitis C virus (HCV) has been recognized as a silent epidemic and an emerging public health threat.1,2 Estimates by the Centers for Disease Control and Prevention suggest that approximately 4 million persons in the United States are infected with HCV.2 Many have not been diagnosed, because fewer than 20% are symptomatic3 and the condition may be latent.4 Chronic HCV infection is the leading cause of liver transplantation in the United States and Europe.5 Hepatitis C virus also may account for a 2-fold increase in the incidence of hepatocellular carcinoma between 1975 and 1998.6 The total societal cost estimates may be as high as $600 million per year in the United States.2

Most of the prevalence data on hepatitis C in the United States are derived from the National Health and Nutrition Examination Study (NHANES) study, which was a survey of noninstitutionalized civilians carried out between 1988 and 1994. The prevalence of anti-HCV was 1.8%, indicating that there were 3.9 million persons infected with HCV, of whom 2.7 million had chronic infection.7 Prevalence rates vary according to the population studied. A San Francisco Veterans Administration medical center study8 of more than 1000 patients indicated an anti-HCV prevalence of 18%, while another study9 of homeless veterans suggested an HCV prevalence of 42%. The global prevalence of anti-HCV is estimated at 2.9%, with lower prevalence rates noted in Western Europe, Australia, and Southeast Asia.10 Healthy People 200011 set a goal of decreasing the prevalence of this virus from 18.3 per 100 000 persons in 1987 to 13.7 per 100 000 persons in 2000. Healthy People 201012 specifies the additional goal of reducing new cases of HCV from 2.4 per 100 000 persons in 1996 to 1 per 100 000 persons in 2010.

Managed care organizations (MCOs) are key sites for surveillance of the prevalence and treatment of HCV for several reasons. First, healthcare delivery has increasingly shifted from the public sector to private healthcare systems through MCOs. Second, the age group most frequently diagnosed as having HCV, ages 30 to 49 years, is likely to be employed and covered by employer-insured healthcare. Approximately 93% of privately insured persons receiving coverage from their employer are enrolled in managed care.13 Third, a national MCO setting provides population-based automated data to determine the prevalence and treatment pattern of HCV in the general medical community. Previous studies have focused on select regional practices, rather than a broader comparison across several geographic areas.14 In addition, most of the published literature on the treatment of HCV summarizes clinical trials that may not reflect treatment patterns in the general medical community.15

The objectives of this retrospective population-based administrative claims study were to determine the prevalence of chronic HCV infection in a national MCO by age, sex, geographic region, and insurance type; to quantify the rate of testing for HCV in a national MCO by these same factors; and to characterize the prescribing of medications for HCV, including patterns of drug use and treatment.

METHODS

Data Source and Study Population

Employer-insured and Medicaid-covered populations of 11 geographically diverse health plans affiliated with UnitedHealth Group were included in this study. These 11 plans, with 3.9 million persons enrolled from January 1, 1997 to December 31, 1999, were located in the following geographic regions: Midwest (6 plans, 2.1 million enrollees), Southeast (3 plans, 1.1 million enrollees), Northeast (1 plan, 450 000 enrollees), and West (1 plan, 326 000 enrollees). The plans were mostly independent practice association models, contracting with large networks of physicians typically reimbursed on a discounted fee-for-service basis.

UnitedHealth Group maintains longitudinally linked computerized claims research databases.16,17 The data used in this study include enrollment files with demographics, outpatient pharmacy claims, and physician and facility claims. The prescription claims database contains information on prescription drugs dispensed to health plan members in the ambulatory care setting from retail pharmacies. Employer-insured members paid a higher copayment for brand drugs compared with generic equivalents. Medications not on the Preferred Drug List were available to enrollees for a higher copayment. Physician claims include services provided by physicians and other health care providers on an outpatient basis (including laboratory tests), whereas hospital and other facility claims include emergency care and inpatient services provided to health plan members.

Analyses were conducted in the aggregate and by geographic region. Patient confidentiality was preserved because the files used for the study analyses did not contain patient-specific identifiers. An independent institutional review board approved this study.

Testing for HCV

During the 3-year study, outpatient physician and facility claims were used to identify members who underwent testing for HCV, using HCV antibody and HCV RNA tests. Hepatitis C testing was defined as at least 1 outpatient claim with a Current Procedural Terminology-4 (CPT-4) procedure code for 1 or more of the following: (1) hepatitis C antibody test (86803); (2) hepatitis panel (80059) that includes hepatitis A, B, and C antibody tests; (3) hepatitis C confirmatory test (86804); or (4) HCV RNA test (87520, 87521, or 87522) used to confirm active infection and monitor disease progression during drug therapy. Laboratory tests from inpatient facility claims were not included in the study because they could not reliably identify tests for HCV, as they are bundled under hospital billing codes. The rate of HCV testing by age, sex, geographic region, and insurance type (employer-insured vs Medicaid) was calculated, using each health plan's enrollee population as a denominator.

Patients With Chronic HCV

A combination of physician, facility, and pharmacy claims files was screened during the study to identify health plan members with chronic HCV, defined as having at least 1 primary or secondary International Classification of Diseases, Ninth Revision (ICD-9) diagnosis code for chronic HCV (070.44 or 070.54) or at least 1 prescription for interferon in combination with ribavirin. The prevalence rate of chronic hepatitis C by age group, sex, geographic region, and insurance type was calculated using enrollee population as a denominator.

Patterns of Drug Use and Treatment

The automated outpatient pharmacy claims of patients with chronic HCV were screened to determine the proportion of patients receiving interferon monotherapy, combination interferon alfa-2b and ribavirin therapy, or no treatment. The following types of interferon were included: interferon alfa-2a, interferon alfa- 2b, interferon alfacon-1, and interferon alfa-n3. Interferons commonly used for the treatment of conditions other than hepatitis C, such as multiple sclerosis, were excluded from this study (eg, interferon beta-1a, interferon beta-1b, and interferon gamma-1b). The percentages of patients with interferon claims alone (monotherapy users), combination therapy claims alone (combination therapy), or both interferon and combination therapy claims (both) were calculated. The specialty type of the prescribing physician was also determined based on the pharmacy claims.

Further analyses of drug treatment patterns, including duration of treatment and baseline and follow-up testing, were completed on a subset of patients meeting certain criteria. First, patients had to be "new users" of these medications. A patient was considered a new user if he or she had no prescriptions for interferon or combination therapy during the 3 months before the first prescription (index date). For some patients, a break in therapy of at least 3 months' duration may signify the start of a new course of therapy. Second, new users had to be continuously enrolled in the health plan, with no gap in enrollment greater than 32 days from at least 3 months before the index date through 6 months after the index date (a minimum of 9 months' continuous enrollment). These additional criteria allowed for appropriate standardized comparisons across treatment groups because patients had to be enrolled at least 9 months and were new users (of these medications). Duration of therapy was determined by calculating the number of months between the patient's first and last prescriptions and then adding the days' supply amount of the final prescription.

Treatment Monitoring

Pharmacy claims were analyzed to determine whether recommended guidelines for monitoring the response to drug therapy were followed. We determined if a patient received a baseline HCV RNA (CPT codes, 87520, 87521, or 87522) or alanine aminotransferase (CPT codes, 84460, 80058, or 80012-80019) test before initiating treatment with interferon alone or combination therapy. In addition, we identified whether a patient received follow-up testing within the first 6 months following treatment initiation.

Statistical Analysis

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