Table 3. Risk of recurrence or death by tumour subtype and treatment arm.

	Hazard ratio (95% confidence interval)
Parameter	Overall DFS	Overall OS	HER2− DFS	HER2− OS
Treatment in ER−	0.361 (0.148, 0.880)	0.375 (0.143, 0.985)	0.374 (0.125, 1.12)	0.306 (0.091, 1.04)
Treatment in ER+	2.43 (0.748, 7.90)	3.07 (0.626, 15.1)	1.78 (0.512, 6.21)	2.32 (0.440, 12.2)
ER− vs ER+ in ZOL	0.958 (0.377, 2.43)	1.12 (0.391, 3.18)	0.832 (0.262, 2.64)	0.835 (0.222, 3.14)
ER− vs ER+ in no ZOL	6.45 (2.08, 20.0)	9.15 (2.01, 41.6)	3.96 (1.19, 13.2)	6.32 (1.31, 30.4)
Propensity score, per 0.01 increase	1.03 (1.002, 1.06)	1.04 (1.01, 1.08)	1.05 (1.01, 1.09)	1.06 (1.01, 1.11)

Abbreviations: DFS=disease-free survival; ER=oestrogen receptor; HER2=human epidermal growth factor receptor-2; OS=overall survival; ZOL=zoledronic acid.

Treatment is ZOL vs no ZOL.