Results of a retrospective database analysis of drug utilization and costs for treatment of chronic hepatitis B virus infection in the northern Netherlands between 2000 and 2006

Abstract

Objectives: The main aims of this work were to describe patterns of medication use in the treatment of chronic hepatitis B virus (HBV) infection in patients in the northern part of the Netherlands and to compare these practices with established guidelines. In addition, the duration of use and the costs of these treatments were investigated.

Methods: We selected subjects from the University of Groningen's IADB.nl database; by 2006, the database provided information about drug utilization from 55 community pharmacies in the northern Netherlands and included a population of 528,911 individuals, of which 49% were male. Eligible subjects had received >or=1 prescription for drugs used to treat chronic HBV infection (ie, lamivudine, pegylated interferon-alpha2a, pegylated interferon-alpha2b, adefovir, tenofovir, and entecavir) between the years 2000 and 2006. The annual prevalence and cumulative incidence of HBV treatment per 1000 people covered in the database were calculated and stratified by sex. Kaplan-Meier survival analysis was used to analyze the duration of use. Drug costs in the treatment were calculated for all patients or per patient, and by drugs used per subperiod (2000-2003 and 2004-2006). Treatments for hepatitis C virus and HIV were excluded from the analyses.

Results: From the database, we identified 59 patients (46 male, 13 female), aged 25 to 60 years, who received >or=1 prescription for a medication to treat chronic HBV infection between 2000 and 2006. The overall prevalence of people using chronic treatments for HBV was between 0.03 and 0.06 per 1000 during the years of the study. The cumulative incidence of treatment was approximately 0.01 per 1000 per year (ranging from a high of 0.021 in 2000 to a low of 0.009 in 2006). When stratified by sex, there were more male than female subjects who received medications for HBV. Lamivudine was the most commonly prescribed drug, followed by adefovir and pegylated interferon-alpha2b. In 2000 and 2001, lamivudine was the only medication prescribed for the treatment of chronic HBV. From 2002 to 2006, the prescription rate for lamivudine dropped from 90% to 61%. In contrast, the prescription rate for adefovir increased from 4% in 2003 to 36% in 2006. Pegylated interferon-alpha2b remained stable at 8% to 11% between 2002 and 2006. Twenty-five percent of patients had stopped HBV treatment by the end of 1 year. Fifty-five percent had stopped by 3 years. Seventy-seven percent of patients received their first HBV prescription from a medical specialist. Per patient, the cost of drug therapy was highest with adefovir. From 2004 to 2006, the cost of adefovir therapy accounted for 49% of total expenditures for the treatment of chronic HBV (equivalent to euro128,037; as of January 2010, euro1.00 = US $1.43). The second and third most expensive drugs were tenofovir and pegylated interferon-alpha2b (euro33,700 and euro33,250, respectively). Costs incurred per patient increased over the years of the study period.

Conclusions: The overall prevalence and cumulative incidence of patients with treatments for chronic HBV were relatively low in the northern part of the Netherlands between 2000 and 2006. The prescribing and utilization patterns were in agreement with international and Dutch guidelines. Given the low numbers of prescriptions, the costs also remained relatively low.