Economic Burden Associated With Patients Diagnosed With Hepatitis C

Abstract

Background

New therapies for Hepatitis C virus (HCV) are under development that will augment pegylated interferon-alpha plus ribavirin to improve patient outcomes. Data documenting the incremental economic and health burden of patients with HCV relative to those who are not infected with HCV will be required to evaluate the comparative effectiveness of these new therapies.

Objective

The objective of this study was to estimate the incremental impact of HCV infection on health care costs and risk of adverse health events.

Methods

Paid claims data for commercially insured patients in the United States were used to identify 2 matched cohorts of 8861 patients with and without HCV infection. Propensity score matching was used to adjust for patient demographics, diagnostic mix, prior use, and drug profile. Patients with prior cirrhosis, liver cancer, or liver transplantation were excluded. Differences in the first postindex year associated with the diagnosis of an HCV infection were estimated for adverse event risk (logistic regression), costs (ordinary least square regression), and utilization counts (generalized linear models), controlling for patient demographics, prior use, comorbidity profile, and prescription drug profile.

Results

The costs of treating patients infected with HCV and a matched sample not infected with HCV were $37,390 and $13,575, respectively. The incremental cost of HCV infection was estimated at +$23,406, primarily because of higher costs for ambulatory care (+$6531), hospital services (+$1827), and prescription drugs (+$6935). The presence of HCV was associated with a significantly higher risk of hospitalization (odds ratio [OR] = 2.5) and number of hospital admissions (+186%); depression (OR = 2.2); cirrhosis (OR = 65.8); hepatic cancer (OR = 28.1), and liver transplantation (OR = 46.1; P < 0.0001 for all estimates).

Conclusions

A diagnosis of HCV infection was correlated significantly with increased adverse event risk and increased health care costs. New alternative treatments are needed that are more efficacious and less burdensome for the patient. Limitations of this study are that only 1 year was used to screen for preexisting conditions and events and that paid claims data do not capture indirect HCV infection costs such as time lost from work.

Introduction

Hepatitis C virus (HCV) is a major medical and public health concern in the United States and worldwide. The Centers for Disease Control and Prevention estimate the prevalence of chronic HCV infection in the United States at between 2.7 and 3.9 million Americans (1.3%–1.9%).¹ Chronic HCV infection is also a significant health care economic burden. The estimated aggregate cost associated with viral infection in the United States was $1.8 billion in 1997, and these costs are expected to increase significantly over the next 2 decades.2, 3, 4 Although serious and costly complications of HCV infection may develop, such as liver failure, the need for liver transplantation, and cancer, patients with chronic HCV infections may delay treatment until after symptoms emerge because of the significant direct and indirect costs associated with current treatments.5, 6

The use of pegylated interferon and ribavirin has been shown to be cost-effective, and even cost-saving in a number of clinical scenarios, but treatment with these drugs can result in a significant patient burden.7, 8, 9, 10, 11, 12 New therapeutic alternatives are being developed that are associated with greater sustained virologic response, with a focus on the most prevalent genotype 1 patients.13, 14 However, the cost of the new therapies may emerge as one of the major barriers to widespread use. New therapies must undergo rigorous cost-effectiveness evaluations by pharmacy and therapeutics committees before they are adopted by health insurers and government agencies. These analyses require current and valid measures of the incremental cost of HCV infections for patients.

Most research into HCV-related costs has estimated the incremental costs of HCV infection relative to the general population without taking into account the advanced age and other cost-related factors that exist in the HCV population.15, 16, 17 As a result, the incremental costs can be overestimated unless adjustments are made for these factors. Rosenberg et al¹⁵ used cross-sectional data for 191 nonelderly HCV-infected patients selected from a large insured New England population. The average cost per newly diagnosed chronic HCV patient was estimated to be $10,812 per patient-year. Poret et al¹⁶ used the MarketScan fee-for-service database and found the cost per patient in the pre-HCV infection period is highest in the 6 months immediately preceding the diagnosis ($4594), and the highest level of spending in the post-HCV period occurred in the first 6 months ($6290). The annual costs across the 24 months before and after the index HCV diagnosis were $6945 and $10,100 per year, respectively. Armstrong and Charland¹⁷ selected 614 patients from a small health maintenance organization who had at least 2 HCV-related diagnoses and 1 year of eligibility following diagnosis using data from a 3-year data window (CY 1997–1999). Costs for this HCV patient sample were compared across 4 groups based on the type of treatment: no drug therapy, interferon-alfa (IFN-α) only, IFN-α + ribavirin (R), and a combination of IFN-α only and IFN-α + R. Most patients (45/614 = 88.8%) were untreated during the year following their index diagnosis. Untreated patients were less costly to treat ($4663); 37% ($1705) of their cost was for HCV-related medical service. Receiving the standard-of-care drug regimen (IFN-α + R only) was correlated with significantly higher total cost ($17,768), which can be broken down into medical cost with an HCV diagnosis ($9212) and the cost of IFN-α + R ($3305).

Two recent studies investigate the incremental health impact of HCV infection relative to a matched, non–HCV-infected population. Steinke et al¹⁸ conducted a case-control study of HCV and non-HCV patients. Their research found that HCV increased the risk of death 8-fold over a 7-year period and tripled both the average number of admissions per patient (4.7 vs 1.5) and readmissions per admitted patient (5.0 vs 1.6). Butt et al¹⁹ used a matched cohort of HCV-infected and -uninfected Veterans Affairs (VA) patients who were identified using the VA data system. The presence of an HCV infection was estimated to increase the risk of death by 37%. Treatment duration was estimated to decrease monotonically the likelihood of death among treated patients relative to untreated patients as follows: 0 to 23 weeks of treatment, hazard ratio (HR) = 0.71; 24 to 47 weeks, HR = 0.60; 48+ weeks, HR = 0.41. However, neither study included data on the incremental health care costs attributable to HCV or the effect of HCV on adverse HCV-related events, such as cirrhosis, hepatic cancer, or liver transplantation.

This study estimates the incremental cost of chronic HCV infection by comparing matched HCV and non-HCV patients derived from a commercially insured population in the United States in order to improve the quality of data regarding the incremental costs associated with HCV infection. Specifically, we hypothesize that patients diagnosed with HCV will exhibit significantly higher treatment costs and an increased risk for adverse clinical events in the first year following diagnosis when compared with matched patients with no HCV diagnosis. The study was not designed to estimate the effects of treatment or to compare the effectiveness of alternative therapies. Instead, the results from this study provide a better understanding of the economic and health burden of HCV infection. Current cost-of-illness data are required by pharmacy and therapeutics committees and policy makers when evaluating the comparative effectiveness of treatments and deciding on future access to the new therapies for HCV that are currently approaching market approval by the Food and Drug Administration.