Population-based estimates of long-term health care costs attributable to hepatitis C

Presenter: Hla-Hla Thein, University of New South Wales

Abstract

Background and Objectives: Hepatitis C virus (HCV) infection imposes an increasing burden on the Canadian health care system as the infected population ages. Quantifying the economic burden of disease is important for planning of care and control programs and for policy implementation. Our aim was to estimate long-term health care costs attributable to HCV.

Methods: A population-based linkage of serologic database including over 95% of all identified cases of HCV in British Columbia (BC) to the BC Linked Health Database identified 20,670 HCV seropositive cases. Cases were matched 1:4 to HCV seronegative controls (n=71,709) based on age, gender, socioeconomic status, place of residence, co-morbidity, and phase of illness. Subjects were followed for up to 8 years from January 1, 1997 to December 31, 2004. The observation time was divided into three phases: the year preceding death (Pre-Death Phase, n=418); the period following decompensated liver disease (Late Phase, n=537); and the time between cohort entry and either of the preceding phases or end of follow-up (Initial Phase, n=19,041). Costs of care (per 100 days) attributable to HCV (mean cost in cases minus mean cost in matched controls) for each phase of illness were estimated using Generalized Estimating Equations to account for the matched design. Per-patient total costs and costs attributable to HCV were applied to Kaplan Meier survival estimates of all HCV cases to estimate 5-year and 8-year costs. Mean total costs were discounted at 5%. We captured costs for physicians’ and other fee-for-service practitioners’ services, drug cost reimbursed by the Provincial Plan, hospital costs, and same day surgery cost.

Results: Mean total costs (per 100 days) attributable to HCV were $507 (95% confidence intervals (CI), $473-$540, 2007 CAD) in the Initial Phase, $1,642 (95% CI, $1,302-$1,983) in the Late Phase, and -$22 (95% CI, -$972-$929) in the Pre-Death Phase. The undiscounted and discounted mean 5-year total costs for HCV cases were $24,243 and $18,995, respectively. The respective mean (95% CI) 5-year total costs attributable to HCV were $7,653 ($7,586-$7,721) and $5,997 ($5,944-$6,050). The undiscounted and discounted mean 8-year costs for HCV cases were $27,257 and $18,449, respectively. The respective mean (95% CI) 8-year total costs attributable to HCV were $9,028 ($9,000-$9,057) and $6,111 ($6,091-$6,130). Mean aggregate 5-year costs of care attributable to HCV were estimated at $153 million for 19,996 cases. Older age, female gender, and co-morbidity were associated with higher costs of care.

Conclusions: Our results suggest that long-term health care costs attributable to HCV are substantial. Costs of care vary by phase of illness, demographic characteristics, and co-morbidity. These results provide useful information for clinicians in developing improved preventive and treatment strategies, and for provincial and federal governments in policy-making and resource allocation.