A COST-EFFECTIVENESS ANALYSIS OF HEPATITIS-B VACCINE IN PREDIALYSIS PATIENTS

Objective. Our objective was to assess the cost effectiveness of hepatitis B vaccine in predialysis patients. Data Sources. Costs were calculated from estimated rates of health services use and unit costs of resource use. Efficacy data were based on probability estimates from the medical literature and included vaccination response rates, anticipated hepatitis B virus (HBV) infection rates, and outcomes from HBV. Study Design. Costs and effectiveness of HBV vaccination was modeled with a decision tree constructed to analyze three vaccination strategies for patients with renal insufficiency: vaccine given prior to dialysis, vaccine given at time of dialysis, and no vaccine. Sensitivity analyses were performed to assess the effect of varying important dinical and cost variables. Data Collection/Extraction Methods. All analyses were based on efficacy and cost estimates derived from the medical literature. Analyses were conducted with the aid of SMLTREE(R) software. Principal Findings. The number of patients requiring vaccination per case of HBV prevented was higher for dialysis patients (625 vaccinees/case prevented) than for predialysis patients (434 vaccinees/case prevented). The cost-effectiveness ratios were $25,313/case of HBV prevented for vaccination at the time of dialysis and $31,111 for the predialysis vaccine. When a higher HBV infection rate (based on clinical trial data) was substituted in the analysis, the cost effectiveness of a predialysis vaccination strategy improved to $856 per case prevented. Results were sensitive to the cost of the vaccine and the incidence of HBV infection in dialysis patients. For the predialysis strategy to become cost saving, the price of the vaccine would have to decrease from $114 to $1.50, or the incidence of infection would have to increase from 0.6 percent to 38 percent, holding all other variables constant. Conclusions. Additional HBV infection can be prevented by immunizing predialysis patients, but the cost is high. Decisions concerning vaccination policy should be influenced by local prevalence of HBV infection.