Direct hospital costs of skeletal-related events (SRE) in Portuguese patients (pts) with breast cancer (BC) and bone metastases

Abstract

17084 Background: SRE such as pathological fractures, spinal cord compression, surgery or radiation therapy to bone and tumour- induced hypercalcemia account for substantial health resource utilization (HRU). The objective of this study was to investigate SRE-related direct hospital costs in Portuguese pts with BC and bone metastases. Methods: Pts with BC and at least one SRE within 12 months prior to study entry were eligible for this retrospective medical record review cost analysis study. SRE treatment cost were calculated by multiplying 12 month health resource utilization frequency (hospitalization, clinic visits, diagnostic tests, drugs) by the corresponding unit costs from the Portuguese Ministry of Health costs database. To account for the skewed nature of the data, costs were modelled using generalized linear models with gamma distribution and log link. Results: A total of 121 pts (age at bone metastases, mean 56.8 years, range 21- 89) from six different hospitals in Portugal were included. Median time from BC diagnosis to bone metastases was 38 months [CI95%: 24–57]. ECOG performance status at the time of SRE was 0 in 24.6% of pts, 1 in 45.9%, 2 in 18.0%, 3 in 8.2% and 4 in 3.3%. Total number of SRE over twelve months was 142 (mean 1.2 SRE/pts, SD=0.4) distributed as follows: pathological fractures (12.7%), spinal cord compression (4.9%), surgery to bone (1.4%), radiation therapy to bone (74.7%) and tumour induced hypercalcemia (6.3%) . Mean SRE treatment cost over 12 months was 5,963€ (SD=3,646€): hospitalization 1,312€, clinic visits 36€, diagnostics 103€, radiotherapy 1,481€, drugs 3,031€. According to biphosphonate (Bph) use in the prior 12 months, the mean (SD; pts) unadjusted SRE treatment cost was: no Bph 2,282€ (1,491; n=4), oral Bph 1,579€ (1,123; n=5), zoledronic acid 6,221€ (2,923; n=77), pamidronate 6,766€ (4,476; n=33). When excluding Bph costs, pamidronate pts were 1.8 [95% CI: 1.3–2.7] times more expensive than zoledronic acid when controlling for pts’ clinical characteristics. Conclusions: This study confirms prior data on the high cost of SRE in pts with BC metastatic to bone [Table: see text]