Pattern of intravenous bisphosphonate use in outpatient care in Germany.

PURPOSE: Intravenous bisphosphonate therapy has recently been associated with the development of an osteonecrosis of the jaws (ONJ). If new adverse events have been linked to drugs, basic information on drug exposure in routine care is essential. The aim of this study was to investigate prevalence as well as duration and cumulative doses of intravenous bisphosphonate treatment.

METHODS

We analysed data of the statutory health insurance company Gmünder ErsatzKasse (GEK) over the years 2000-2006. We first estimated treatment prevalence in 2006. We further studied a cohort of new users of intravenous bisphosphonates who initiated treatment between 1 January 2001 and 31 December 2005. We used the Kaplan-Meier method to estimate the time to end of treatment (composite of discontinuation and death).

RESULTS

A total of 1024 patients received at least one dose of intravenous bisphosphonates in 2006. The most commonly prescribed agent was zoledronate (53.7%). After standardizing for sex and age, an estimated 0.1% of the German population would have been treated in 2006. Of 1259 new users in 2001-2005, an estimated 40% of men and 22% of women died within 12 months. The median treatment duration was 3.5 months in men and 5.7 months in women. This difference disappears when studying only survivors.

CONCLUSIONS

Although our study suggests that intravenous bisphosphonates were prescribed mainly for short durations, this result is strongly influenced by the fact that new users had a poor prognosis with a short life expectancy.