Table 3.

Cox proportional-hazards regression analyses of depression predicting mortality

	Breast cancer mortality		All-cause mortality
	HR (95 % CI)	p value	HR (95 % CI)	p value
Stage I (n = 804)
Depression	n/a	n/a	2.30 (1.02–5.15)	0.044
Depression × age	n/a	n/a	0.92 (0.86–0.99)	0.030
Stage II (n = 580)
Depression	2.53 (1.32–4.86)	0.005	2.01 (1.16–3.48)	0.013
Depression × age	1.01 (0.95–1.08)	0.735	1.00 (0.95–1.06)	0.918
Stage III (n = 220)
Depression	0.99 (0.47–2.10)	0.979	0.92 (0.47–1.80)	0.801
Depression × age	0.99 (0.91–1.07)	0.718	0.95 (0.89–1.02)	0.144
Stage IV (n = 42)
Depression	0.57 (0.16–2.03)	0.388	1.15 (0.38–3.46)	0.807
Depression × age	0.95 (0.78–1.16)	0.606	1.06 (0.93–1.21)	0.403

Separate analyses by tumor stage with control of the variables listed in Table 2. Proportionality of hazards was tested within each stage and for each outcome and adjusted accordingly. Test statistics represent hazard ratios with 95 % confidence interval (HR (95 % CI))