Renal dysfunction associated with bisphosphonate use: Retrospective analysis of 293 patients with respect to age and other clinical characteristics

Abstract

8039 Background: Bone destruction and metastasis are common causes of morbidity in patients with variety of malignancies. Bisphosphonates are a class of agents that have been shown in a variety of studies to reduce bony complications associated with cancer. Studies have shown renal toxicity associated with bisphosphonates especially following the exposure of zoledronic acid. Published literature suggests renal function deterioration occurs in 8.8–15.2% of patients at recommended dose of 4 mg infused intravenously over 15 minutes. Methods: We retrospectively reviewed the records of all patients receiving bisphosphonates during the period 1/02–6/03 at our instiution. 293 patients were analyzed with variety of malignancies across all ages. Patients were categorized to the type and sequence of bisphosphonates (pamidronate vs. zoledronate and pamidronate followed by zoledronate), underlying diagnoses, age and sex. Renal dysfunction was defined as an increase in serum creatinine of >0.5 mg/dl over baseline. Results: There were 35 patients (12%) who developed renal dysfunction. The incidence of renal toxicity was more prominent in the elderly group (>80 years old) with use of bisphosphonates. Increase in serum creatinine was observed in 20% (n=7/35) of elderly group when compared to other age groups (11%;28/258). Also when the type of bisphosphonate use was analyzed among patients with renal dysfunction (n=35) there were only 5 cases in pamidronate only group while 30 developed renal dysfunction with zoledronate de novo (10) or zoledronate with prior use of pamidronate (20). In elderly group all cases with renal dysfunction except one had exposures with zoledronate. Conclusion: Renal dysfunction occurs in all age groups with use of bisphosphonates. This toxicity seem to be more common in patients exposed to both drugs. The elderly may be particularly susceptible. Although we have not analyzed the impact of associated comorbidities leading to renal insufficiency in this analysis, the elderly patients may require closer monitoring of renal function with the use of bisphosphonates. No significant financial relationships to disclose.