Zoledronic acid versus pamidronate as palliative therapy in cancer patients: A Canadian time and motion analysis

Abstract

Pamidronate was an important advance in the palliative treatment of patients with cancer. However, pamidronate must be infused over at least 2 hours in most patients. Zoledronic acid represents the next-generation bisphosphonate with a potential for improved efficacy in the palliative care setting. One important advantage of zoledronic acid is that it can be administered over a 15-minute infusion. To measure the overall efficiency of zoledronic acid as compared with pamidronate in the outpatient setting, a USA microcosting model was adapted to Canadian inputs. Time and motion data were collected from six patients being treated with zoledronic acid or pamidronate in three USA outpatient cancer clinics. Resource use and time impact on outpatient clinical staff were reanalyzed using Canadian cost estimates. This included the evaluation of fixed, variable, and labour costs obtained from Canadian sources. The manufacturer provided drug costs. The base case analysis assumed a 5300-ft² out-patient chemotherapy clinic with eight infusion chairs designated for bisphosphonate administration in the province of Ontario. Mean treatment times in the original USA data collected were 2 hours, 52 minutes for pamidro-nate, and 1 hour, 6 minutes for zoledronic acid (a difference of 1 hour, 46 minutes). In the Canadian version of the microcosting model, the overall treatment cost was Can$673 for pamidronate and Can$682 for zoledronic acid (2001 Canadian dollars). Findings suggest that the shorter zoledronic acid infusion time would allow an additional 27 bisphosphonate patients to be treated per day. Alternatively, approximately one additional hour of chair time could be made available with each zoledonic acid infusion. Sensitivity analyses revealed that (a) the base case results were consistent when geographic region was varied, and (b) the shorter the infusion time for zoledronic acid relative to pamidronate, the lesser the cost difference and more patients could be treated daily. In conclusion, zoledronic acid may enhance the overall efficiency of outpatient chemotherapy clinics by reducing patient waiting time for bisphosphonate administration. These benefits would be obtained at an incremental cost of Can$9 per infusion.