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

Figures & data

Figure 1. Example for identifying SRE episodes with 90-day gap. Gaps were defined based on the number of days without SRE claims starting with the last SRE claim. PF, Pathological fracture; RT, Radiotherapy; SB, Surgery to bone; SCC, Spinal cord compression.

Table 1. Selection of study subjects.

Criteria	n	%
Confirmed diagnosis of bone metastases, confirmed diagnosis of breast cancer prior to bone  metastases diagnosis, and one or more  SRE claims during the follow-up period	9142	100.0
Exclusions (not mutually exclusive)
Less than 6 months of continuous enrollment  prior to index date	2788	30.5
More than one type of primary cancer prior to  index date	609	6.7
Male patients	31	0.3
Total excluded	3333	36.5
Remaining	5809	63.5

SRE, Skeletal-related event.

Table 2. Patient characteristics at baseline (n = 5809).

Characteristic	n (%) or Mean (SD)
Index year, n (%)
2003	330 (5.7)
2004	513 (8.8)
2005	587 (10.1)
2006	687 (11.8)
2007	827 (14.2)
2008	876 (15.1)
2009	1055 (18.2)
2010	721 (12.4)
2011	213 (3.7)
Age, years, Mean (SD)	52.9 (8.0)
Males, n (%)	0 (0.0)
Region, n (%)
South	2568 (44.2)
North Central	1442 (24.8)
West	975 (16.8)
Northeast	699 (12.0)
Unknown	125 (2.2)
Plan type, n (%)
PPO	3586 (61.7)
Comprehensive	385 (6.6)
HMO	871 (15.0)
Other	967 (16.6)
Charlson index, Mean (SD)^a	4.7 (3.2)
Healthcare utilization, n (%)^a
Chemotherapy	388 (6.7)
Systemic corticosteroid	1510 (26.0)
IV Bisphosphonate	61 (1.1)
Opioid	3018 (52.0)
Oral Bisphosphonate	261 (4.5)
Cardiovascular medication	2259 (38.9)
Diabetes medication	409 (7.0)
Hospitalization	967 (16.6)
Emergency department visit	1346 (23.2)
Homehealth	1069 (18.4)
Hospice	12 (0.2)
Skilled nursing facility	29 (0.5)
Physician office visit	5612 (96.6)
Hospital outpatient visit	5258 (90.5)
Lab visits	2272 (39.1)
Other encounters	1114 (19.2)
Number of healthcare claims, Mean (SD)^a,^b
Chemotherapy	0.22 (1.11)
Systemic corticosteroid	0.49 (1.09)
IV Bisphosphonate	0.03 (0.30)
Opioid	1.98 (3.45)
Oral Bisphosphonate	0.12 (0.65)
Diabetes medication	0.35 (1.63)
Hospitalization	0.23 (0.61)
Emergency department visit	0.44 (1.37)
Hospice	0.02 (0.72)
Skilled nursing facility	0.02 (0.41)
Physician office visit	13.5 (11.2)
Hospital outpatient visit	7.0 (8.2)
Lab visits	1.38 (2.75)
Other encounters	0.51 (2.19)
Healthcare costs, $, Mean (SD)^a
Hospitalization	4073 (15,333)
Emergency department visit	373 (2895)
Homehealth	260 (1357)
Hospice	11 (339)
Skilled nursing facility	50 (1468)
Physician office visit	10,115 (18,798)
Hospital outpatient visit	13,131 (27,216)
Lab visits	197 (659)
Other encounters	292 (2722)
Duration of follow-up, months, Mean (SD)	17.2 (15.2)

^aCalculated over 6 months prior to index date.

^bValues are numbers of claims. Except for medications, claims on the same day are counted once.

Costs are in 2010 US dollars.

HMO, Health maintenance organization; IV, intravenous; PPO, Preferred provider organization; SD, Standard deviation.

Table 3. Number of SRE episodes by types of SRE claims identified within each episode among patients with breast cancer and bone metastases.

SRE classification	Inpatient, n (%)	Outpatient, n (%)	All episodes, n (%)
Spinal cord compression (SCC)
SCC only	6 (7.2)	12 (40.0)	18 (15.9)
SCC and PF	3 (3.6)	0 (0.0)	3 (2.7)
SCC and SB	1 (1.2)	0 (0.0)	1 (0.9)
SCC and RT	26 (31.3)	16 (53.3)	42 (37.2)
SCC and PF and SB	3 (3.6)	0 (0.0)	3 (2.7)
SCC and PF and RT	14 (16.9)	1 (3.3)	15 (13.3)
SCC and SB and RT	5 (6.0)	1 (3.3)	6 (5.3)
SCC and PF and SB and RT	25 (30.1)	0 (0.0)	25 (22.1)
Total	83 (100.0)	30 (100.0)	113 (100.0)
Pathological fracture (PF)
PF only	105 (12.5)	277 (50.2)	382 (27.5)
PF and SB	173 (20.6)	31 (5.6)	204 (14.7)
PF and RT	214 (25.5)	213 (38.6)	427 (30.7)
PF and SB and RT	346 (41.3)	31 (5.6)	377 (27.1)
Total	838 (100.0)	552 (100.0)	1390 (100.0)
Surgery to bone (SB)
SB only	66 (45.5)	23 (50.0)	89 (46.6)
SB and RT	79 (54.5)	23 (50.0)	102 (53.4)
Total	145 (100.0)	46 (100.0)	191 (100.0)
Radiotherapy (RT)	658 (100.0)	5265 (100.0)	5923 (100.0)
Total	1724 (100.0)	5893 (100.0)	7617 (100.0)

SRE, Skeletal-related event. Percentages were calculated for each episode type: inpatient, outpatient, and all episodes.

Figure 2. Mean (95% CI) cost of inpatient and outpatient SRE episodes among patients with breast cancer and bone metastases by type of SRE (number of patients = 5809): (A) Inpatient SRE episodes; and (B) Outpatient SRE episodes.