Are long-term bisphosphonate users a reality? Dose years for current bisphosphonate users assessed using the danish national prescription database.

UNLABELLED: The prevalence of long-term bisphosphonate use may be low due to low refill compliance and gaps in treatment. An analysis of the prescription history of 58,674 bisphosphonate users in Denmark found that only 2.8 % had received ten dose years of treatment or above.
INTRODUCTION: This study aims to describe the demographics of present bisphosphonate (BP) users, to determine the prevalence of long-term BP use, and to establish if long-term use (a 10-year history of osteoporosis treatment) translated to ten dose years of bisphosphonate prescriptions filled, given the propensity for treatment gaps and low refill compliance with bisphosphonates.
METHODS: The study population was all persons aged 35 and above, who had filled at least one prescription for an oral bisphosphonate in the year 2008. Past use of osteoporosis medications (bisphosphonates, raloxifene, strontium ranelate, or PTH analogs) for the period January 1, 1995 to December 31, 2007 was retrieved from the Danish National Prescription Database for descriptive analysis.
RESULTS: Of the 58,674 BP users, 46 % were above the age of 75, and 13 % were men. Though 5.9 % had at least a 10-year history of treatment, only half (2.8 %) had received more than ten dose years of a BP. For any osteoporosis drug, 3.0 % had received ten dose years or more, while 23.2 % had received between 5 and 10 years of treatment.
CONCLUSION: Long-term users with ten dose years or more of a BP are rare due to periods of low compliance and gaps, with a discrepancy between the length of treatment and doses taken. The study also highlights the great number of patients who have used BP for more than five dose years and should be advised on length of treatment, a decision process that will be difficult due to the paucity of long-term safety and efficacy data.