Table 2.

Univariate analysis of OS

		^SIPTW−OS
^Variable	^HR	^95%CI	^P
^{ASA II}	^1.46	^1.00–2.13	^0.052
^{ASA III}	^2.35	^1.26–4.36	^0.007
^{Adjuvant treatment Yes}	^0.76	^0.59–0.97	^0.028
^{Blood transfusion Yes}	^1.09	^0.63–1.88	^0.755
^{Duration of anesthesia}	^1.01	^0.94–1.09	^0.717
^{Degree of differentiation}	^0.74	^0.55–0.98	^0.039
^Group	^0.87	^0.67–1.13	^0.307
^{Postoperative hospital stay}	^1.01	^1.00–1.02	^0.199
^{Pathological classification} ^{Squamous carcinoma}	^2.03	^0.58–7.13	^0.269
^{Surgical type McKeown}	^1.21	^0.92–1.59	^0.179
^{Surgical type Sweet}	^0.80	^1.26–0.58	^0.145
^{Surgical type Thoracoabdominal incision}	^1.04	^0.96–0.64	^0.865
^{TNM II}	^1.17	^0.80–1.70	^0.410
^{TNM III}	^1.57	^1.10–2.23	^0.013
^{Tumor location Middle esophagus}	^1.28	^0.98–1.66	^0.072
^{Tumor location Upper esophagus}	^1.54	^1.04–2.29	^0.031
^{Total hospital stay}	^1.01	^1.00–1.03	^0.044
^{The length of the operation}	^1.01	^0.94–1.10	^0.727