Table 2.

Univariate and multivariate analysis of survival outcomes of hormone receptor-positive metastatic breast cancer patients.

Characteristics	PFS				OS
	Univariate HR (95% CI)	P	Multivariate HR (95% CI)	P	Univariate HR (95% CI)	P	Multivariatea HR (95% CI)	P
Initial systemic therapy
Initial chemotherapy	1	0.0452	1	0.0472	1	0.2623	1	0.0004
Initial endocrine therapy	0.84 (0.70–0.99)		0.83 (0.69–0.99)		0.90 (0.75–1.08)		0.71 (0.58–0.86)
Primary metastatic disease
No	1	<0.0001	1	0.0004	1	0.0765	—	—
Yes	0.69 (0.58–0.83)		0.71 (0.59–0.86)		0.85 (0.70–1.02)		—
Initial metastatic sites
Bone only	1	0.0016	1	0.0158	1	0.0007	1	0.1673
Visceral or multiple	1.34 (1.12–1.60)		1.26 (1.04–1.51)		1.40 (1.15–1.69)		1.15 (0.94–1.41)
Hormonal status
Premenopausal	1	0.1695	1	0.2323	1	0.0001	1	0.1434
Postmenopausal	1.16 (0.94–1.43)		1.15 (0.92–1.43)		1.55 (1.29–1.87)		1.23 (0.93–1.63)
Charlson Comorbidity Index (CCI)
CCI = 0	1	0.0368	1	0.0297	1	<0.0001	1	0.0195
CCI > 0	1.20 (1.01–1.42)		1.22 (1.02–1.47)		1.51 (1.23–1.84)		1.27 (1.04–1.55)
Primary endocrine resistance
No	1	0.0215	1	0.4450	1	0.0565	1	0.2596
Yes	1.32 (1.04–1.67)		1.10 (0.86–1.42)		1.27 (0.99–1.63)		1.17 (0.89–1.53)
Age at MBC diagnosis
<65 years	1	0.5689	—	—	1	<0.0001	1	0.0147
≥65 years	1.05 (0.89–1.25)		—		1.64 (1.36–1.98)		1.32 (1.06–1.65)
Primary tumour type
Ductal	1	0.7039	—	—	1	0.8611	—	—
Lobular	1.04 (0.84–1.30)		—		1.02 (0.81-1.29)		—
Primary tumour diagnosis year
<2008	1	0.2060	—	—	1	0.8779	—	—
≥2008	1.12 (0.94–1.34)		—		1.01 (0.84–1.22)		—

Bold values indicate statistically significant results.

MBC metastatic breast cancer.

^aWith an interaction between “primary metastatic disease” and time.