The present study evaluates the proportion of patients who had re-infusion of intravenous zoledronate after first administration and identifies the factors that contribute to discontinuation.
Introduction: In terms of persistence, annual administration of zoledronate seems to overcome a shortcoming of oral bisphosphonate. However, little information is available concerning persistence with intravenous zoledronate for osteoporosis in a usual care setting. The aim of this study was to assess the persistence of intravenous zoledronate after first administration and to identify the factors that contribute to its discontinuation.
Methods: A questionnaire survey concerning the second administration of zoledronate was performed on 259 patients, who had been administered with first intravenous zoledronate injection between January 2009 and December 2009, when they visit for second injection. The questionnaire asked whether patients were administered a second zoledronate injection or not, and non-persistent patients were asked why they declined the second infusion.
Results: One hundred and ninety-two patients revisited our outpatient clinic a year after first visit, and 94 patients (36.3%, 94/259) agreed to a second injection. Of the 136 patients that completed the questionnaire, 47 refused second administration and requested a change to oral bisphosphonate. Thirty-nine of the 47 patients (83%) stated that post-infusion syndrome was the reason why they refused the second administration.
Conclusion: Although the effects of annual intravenous zoledronate are guaranteed to last for a year, this study shows that only a third of patients agree to second administration. The factors associated with discontinuation were male gender, adverse effects (especially post-infusion syndrome) and under-explanation of intravenous drug. These findings should be of concern to clinicians and indicate that patients should be informed before the administration.