Renal function changes and NHS resource use in breast cancer patients with metastatic bone disease treated with IV zoledronic acid or oral ibandronic acid: a four-centre non-interventional study

Abstract

Aims: To describe renal function monitoring practice in patients with metastatic bone disease (MBD) treated with IV zoledronic acid (ZA) and oral ibandronic acid (IA), the management pathways and NHS hospital resources used.

Methods: Medical records of 189 patients; IA (91), ZA (98) with primary breast cancer and MBD were reviewed, and data collected on renal monitoring and hospital visits during bisphosphonate therapy. Time and motion review of resources to administer the bisphosphonates was also conducted.

Results: Only 30% of patients given ZA and no patient given IA had baseline creatinine clearance (CrCl) recorded. Calculated baseline CrCl suggested impaired renal function in 33% ZA and 29% IA patients. Dose reductions were not made correctly in 29 ZA and 2 IA patients whose monitoring suggested it. ZA patients made more clinic and day care attendances than IA-treated patients, at twice the cost. Staff activity and patient time per visit was higher with ZA than IA.

Conclusion: Although limited by retrospective design, these results demonstrate that in many patients, CrCl is not calculated before or during treatment with bisphosphonates. Renal function deteriorated in many patients during therapy. In view of these effects, practice should be reviewed to ensure appropriate dosing.

Key words::

• biphosphonates
• breast neoplasms
• health resources
• ibandronic acid
• renal insufficiency
• zoledronic acid

Transparency

Declaration of funding: This study was funded by an educational grant from Roche Products Ltd covering the cost of protocol drafting, obtaining approvals, data collection and analysis and manuscript preparation.

Declaration of financial/other relationships:S.H. and R.J.G. have disclosed that they have no relevant financial relationships; T.H. has disclosed that he has received honoraria from Roche and Novartis in the past (unrelated to this study); F.P. has disclosed that she is an employee of pH Associates, which received funding from Roche to complete this study. E.H. has disclosed that she is an employee of Roche Products Ltd.

The JME peer reviewers 1 and 2 have not received an honorarium for their review work on this manuscript. Both have disclosed that they have no relevant financial relationships.

AcknowledgmentsThe authors are grateful to Dr C Lowdell, Charing Cross Hospital and Dr O Al Salihi, Hammersmith Hospital for contributing data to this study.