Table 5.

Factors associated with postoperative mortality in patients with breast cancer after propensity score matching

Variables	Univariate				Multivariate
	HR	95% CI		P-value	HR	95% CI		P-value
Dexamethasone
No	1 (ref)				1 (ref)
Yes	1.223	0.733	2.041	0.442	1.506	0.886	2.561	0.130
Age	1.005	0.983	1.028	0.636
Age (years)
< 40	1 (ref)				1 (ref)
40–49	0.607	0.331	1.113	0.107	0.979	0.517	1.855	0.949
50–59	0.763	0.416	1.400	0.382	0.778	0.411	1.473	0.440
60–69	1.165	0.574	2.364	0.673	0.962	0.419	2.208	0.927
≥70	1.087	0.318	3.714	0.894	0.866	0.226	3.323	0.834
BMI	0.991	0.925	1.063	0.810
BMI (kg m−2)
< 18.4	0.852	0.542	3.358	0.520	0.759	0.179	3.216	0.709
18.4–22.9	1 (ref)				1 (ref)
23–24.9	1.449	0.765	1.757	0.485	1.647	0.994	2.730	0.053
25–29.9	1.012	0.597	1.417	0.703	1.008	0.584	1.740	0.976
≥30
HTN
No	1 (ref)
Yes	1.692	1.052	2.723	0.030
DM
No	1 (ref)
Yes	1.775	0.858	3.672	0.122
Anaesthetic agents
TIVA	1 (ref)				1 (ref)
Volatile	1.050	0.258	4.272	0.946	1.400	0.332	5.892	0.647
N2O
No	1 (ref)
Yes	1.523	0.840	2.763	0.166
Transfusion
No	1 (ref)				1 (ref)
Yes	6.113	1.503	24.857	0.011	3.063	0.6900	13.600	0.141
Premedicationa
No	1 (ref)
Yes	0.796	0.515	1.231	0.305
Surgical procedure
BCS	1 (ref)				1 (ref)
Mastectomy	2.699	1.652	4.408	< 0.001	2.289	1.367	3.833	0.002
TNM staging
1	1 (ref)				1 (ref)
2	2.403	1.293	4.466	0.006	1.553	0.774	3.117	0.216
3	8.587	4.770	15.458	< 0.001	5.509	2.732	11.106	< 0.001
Oestrogen receptor
No	1 (ref)				1 (ref)
Yes	0.338	0.222	0.514	< 0.001	0.699	0.374	1.305	0.261
Progesterone receptor
No	1 (ref)				1 (ref)
Yes	0.280	0.180	0.435	< 0.001	0.428	0.228	0.803	0.008
Chemotherapy
No	1 (ref)				1 (ref)
Yes	4.667	2.156	10.103	< 0.001	1.381	0.549	3.474	0.493
Radiotherapy
No	1 (ref)
Yes	1.473	0.926	2.343	0.102

CI confidence interval, HR hazard ratio, BMI body mass index, HTN hypertension, DM diabetes mellitus, TIVA total intravenous anaesthesia, N₂O nitrous oxide, BCS breast conserving surgery, TNM tumour-node-metastasis

In 1 to 5 propensity matching process, the basic characteristics of 1224 subjects in the control group were considered to be different from the dexamethasone group and excluded from the final matching analyses. Consequently, 234 patients who received dexamethasone and 1170 patients who did not receive dexamethasone were included

^aPremedication: Midazolam 0.03 mg kg⁻¹ was administered