Audit of zoledronic acid prescribing for multiple myeloma at North Bristol NHS Trust (NBT)

ABSTRACT

Background: Bone loss is a well-recognised complication of myeloma, affecting up to 90% of patients. It is associated with fractures, spinal cord compression and hypercalcaemia. 1,2 Myeloma patients are routinely prescribed zoledronic acid, which has been shown to prevent skeletal-related events, preserve bone density and prolong progression-free survival.3 At NBT, zoledronic acid is prescribed on a paper prescription chart, which is not routinely reviewed by a pharmacist This process is not in accordance with other therapy, which is prescribed on ChemoCare and clinically verified by a pharmacist prior to administration. Objectives • To assess the adherence of zoledronic acid prescribing at NBT against the South West Clinical Network (SWCN) protocol. • To identify areas for improvement in the prescribing of zoledronic acid for prevention of skeletal events. Standards 100% of patients receiving zoledronic treatment should meet the following go-ahead criteria4 • Acceptable bloods within seven days of treatment (creatinine, calcium, phosphate, magnesium) • Comprehensive dental examination. • Dose modification based on creatinine clearance. • Treatment deferred if hypocalcaemia or hypophosphataemia. Methodology: The audit was conducted over a one month period between 1/11/2020 and 30/11/2020. A total number of 58 prescriptions were included in the audit. The data collection sheet for the audit included;patient details, date of treatment and zoledronic acid dose. This information was extracted from the drug charts. The information system ICE was used to verify the blood results and validity period. Creatinine clearance was calculated using the Cockcroft and Gault equation. The medical notes were reviewed for evidence of dental checks. Data was recorded on Excel for further analysis by the pharmacist. Results: An overview of all four audit standards is shown in Figure 1. Two of the four audit standards were fully met (standards 2 and 4). 2% of patients (n= 1/58) did not receive an appropriate zoledronic acid dose adjustment based on renal function (standard 3). 36% (n=21/58) of patients did not have bloods within seven days of treatment (standard 1), however all of these patients had bloods within a month of treatment, in line with the Summary of Product Characteristic recommendations.5 Discussion and conclusion: The audit demonstrated that adherence to zoledronic acid prescribing guidelines is generally satisfactory;however several areas for improvement were identified. Feedback was provided to the haematology team and the following recommendations made • Critical bloods must be done within one week of treatment. • Evidence of a dental examination must be clearly documented. • An approved app must be used for calculating creatinine clearance. • Introduction of a pharmacist clinical verification. • Zoledronic acid should be prescribed on ChemoCare, to assist with the above recommendations. Limitations: This audit was only carried out over a month which will only provide a snapshot of prescribing and results may have been impacted by the COVID-19 pandemic. It was difficult to find documentation for dental checks and treatment delays due to bloods and in some cases, information had to be verified by the prescriber.