Establishing and clinically validating a machine learning model for predicting unplanned reoperation risk in colorectal cancer

Table 1 Comparison of the clinical data of the two groups of patients

	Control group (n = 1984)	Experiment group (n = 60)	χ2/t	P value
Age (yr)
≥ 60	1151	48	11.609	< 0.001
< 60	833	12
Gender
Male	1131	43	5.120	0.024
Female	853	17
BMI (kg/m2)
≥ 24	1250	36	0.225	0.635
< 24	734	24
History of hypertension
Yes	615	27	5.300	0.021
No	1369	33
History of diabetes
Yes	238	6	0.221	0.639
No	1746	54
History of stroke
Yes	238	9	0.495	0.482
No	1746	51
History of laparotomy
Yes	337	20	10.797	0.001
No	1647	40
Hypoproteinemia
Yes	181	12	8.058	0.005
No	1803	48
Location of the tumor
Colon	1250	36	0.225	0.635
Rectum	734	24
History of preoperative radiation therapy
Present	198	7	0.184	0.668
No present	1786	53
History of preoperative chemotherapy
Present	238	8	0.098	0.753
No present	1746	52
TNM staging
I + II	1171	32	0.778	0.378
III + IV	813	28
ASA classification
I + II	1786	51	1.613	0.204
III + IV	198	9
Surgical time (min)
≥ 240	675	30	6.580	0.010
< 240	1309	30
Intraoperative bleeding (mL)
≥ 120	218	4	1.123	0.289
< 120	1766	56
PNI	46.21 ± 5.15	38.97 ± 4.75	10.749	< 0.001

TNM: Tumor-node-metastasis; BMI: Body mass index; ASA: American Society of Anesthesiologists; PNI: Prognostic nutritional index.