Natural history of malignant bone disease in breast cancer and the use of cumulative mean functions to measure skeletal morbidity

Table 3 Univariate analysis for overall survival

Variable	RR	(95% CI)	pvalue
Age ≥ 50 years	0.96	(0.68, 1.35)	0.802
ECOG performance status
2 – 3 versus 0 – 1	1.49	(1.06, 2.12)	0.024
Hydroxyproline/creatinine ratio (centered)	1.04	(1.02, 1.07)	0.001
Bone-specific alkaline phosphatase (U/L)	1.00	(1.00, 1.01)	0.415
Estrogen-receptor status versus negative
Positive	0.67	(0.42, 1.06)	0.085
Unknown	0.96	(0.64, 1.44)	0.857
Progesterone-receptor status versus negative
Positive	0.61	(0.40, 0.93)	0.022
Unknown	0.70	(0.49, 0.99)	0.047
Sites of metastasis (yes versus no)
Bone as only metastatic site	0.90	(0.65, 1.26)	0.553
Lung	1.43	(0.89, 2.30)	0.139
Liver	1.12	(0.69, 1.79)	0.653
Time from diagnosis of bone metastases to study entry, years	1.10	(1.00, 1.21)	0.059
Time from cancer diagnosis to study entry, years Lesion characteristics and numbers	1.00	(0.95, 1.03)	0.630
≥ 3 osteolytic versus < 3 osteolytic	1.29	(0.93, 1.80)	0.128
1 – 2 osteoblastic versus no osteoblastic	0.98	(0.65, 1.48)	0.935
≥ 3 osteoblastic versus no osteoblastic	0.75	(0.62, 0.91)	0.003
1 – 2 mixed versus no mixed	0.81	(0.48, 1.36)	0.423
≥ 3 mixed versus no mixed	1.03	(0.67, 1.58)	0.896
Prior fracture (yes versus no)	1.18	(0.78, 1.77)	0.440
Pain scores (centered)	1.07	(1.01, 1.13)	0.034
Prior chemotherapy (yes versus no)	1.85	(0.59, 5.87)	0.294
≥ 2 prior hormonal therapies (yes versus no)	1.31	(0.94, 1.82)	0.110
Prior radiotherapy (yes versus no)	1.15	(0.80, 1.64)	0.464

Values in bold represent statistically significant correlations.
RR = Relative risk, CI = Confidence interval, ECOG = Eastern Cooperative Oncology Group, U = Units.

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