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.

Table 2 Multiple logistic regression analysis

	β	SE	χ2	P value	OR	95%CI
						Lower	Upper
Age	1.072	0.335	10.268	0.001	2.922	1.516	5.63
Gender	-0.717	0.301	5.674	0.017	0.488	0.27	0.881
History of hypertension	0.592	0.278	4.545	0.033	1.807	1.049	3.115
History of stroke	0.306	0.392	0.61	0.435	1.358	0.63	2.926
History of laparotomy	0.939	0.297	9.986	0.002	2.557	1.428	4.576
Hypoproteinemia	0.918	0.357	6.59	0.010	2.504	1.242	5.045
TNM staging	-0.286	0.275	1.081	0.299	0.751	0.438	1.288
ASA classification	-0.308	0.396	0.605	0.437	0.735	0.339	1.597
Surgical time	0.509	0.276	3.387	0.066	1.663	0.967	2.859
PNI	2.476	0.369	45.073	< 0.001	11.894	5.773	24.505

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

Table 3 Comparison of baseline data between training group and validation group

	Training group (n = 1429)	Validation group (n = 615)	χ2	P value
Reoperation
Yes	40	20	0.309	0.578
No	1389	595
Age (yr)
≥ 60	853	346	2.088	0.148
< 60	576	269
Gender
Male	817	357	0.135	0.713
Female	612	258
BMI (kg/m2)
≥ 24	891	395	0.649	0.421
< 24	538	220
History of hypertension
Yes	451	191	0.051	0.822
No	978	424
History of diabetes
Yes	164	80	0.959	0.327
No	1265	535
History of stroke
Yes	174	73	0.038	0.845
No	1255	542
History of laparotomy
Yes	248	109	0.041	0.840
No	1181	506
Hypoproteinemia
Yes	144	49	2.238	0.135
No	1285	566
Location of the tumor
Colon	894	392	0.256	0.613
Rectum	535	223
History of preoperative radiation therapy
Present	144	61	0.012	0.913
No present	1285	554
History of preoperative chemotherapy
Present	173	73	0.023	0.880
No present	1256	542
TNM staging
I + II	825	378	2.471	0.116
III + IV	604	237
ASA classification
I + II	1281	556	0.275	0.600
III + IV	148	59
Surgical time (min)
≥ 240	476	229	2.933	0.087
< 240	953	386
Intraoperative bleeding (mL)
≥ 120	145	77	2.502	0.114
< 120	1284	538
PNI
≥ 43.76	487	207	0.034	0.854
< 43.76	942	408

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