Healthcare costs associated with skeletal-related events in breast cancer patients with bone metastases.

BACKGROUND: Patients with bone metastases secondary to breast cancer are pre-disposed to skeletal-related events (SREs), including spinal cord compression (SCC), pathologic fracture (PF), surgery to bone (SB), and radiotherapy to bone (RT).
OBJECTIVE: To document current patterns of healthcare utilization and costs of SREs in patients with breast cancer and bone metastases.
METHODS: This was a retrospective, observational study using the Thomson MedStat MarketScan Commercial Claims and Encounters database from 9/2002 to 6/2011. Study subjects included all persons with claims for breast cancer and for bone metastases, and ≥1 claims for an SRE. Unique SRE episodes were identified based on a gap of at least 90 days without an SRE claim, and classified by treatment setting (inpatient or outpatient) and SRE type (SCC, PF, SB, or RT).
RESULTS: Of 17,266 patients with breast cancer and bone metastases, 9142 (53%) had one or more SRE episodes. Among 5809 patients who met all other criteria, there were 7617 SRE episodes over mean (SD) follow-up of 17.2 (15.2) months. The percentage of episodes that required inpatient treatment ranged from 11% (RT) to 76% (SB). On average, inpatient SCC episodes (n=83 episodes) were most costly; while outpatient PF episodes (n=552 episodes) were least costly. Of the total SRE costs (mean [SE] $21,072 [$36,462]/episode), 36% were attributable to outpatient RT (n=5265 episodes) and 31% to inpatient PF (n=838 episodes). LIMITATIONS: The administrative claims data used in this study may lack sensitivity and specificity for identification of clinical events and may not be generalizable to other populations. Also, for some SRE episode categories, the number of events was small and cost estimates may lack precision.
CONCLUSION: In patients with breast cancer and bone metastases, SREs are associated with high costs and hospitalizations.