Predictive value of serum calcium ion level in patients with colorectal cancer: A retrospective cohort study

Table 1 Baseline data of 280 patients with colorectal cancer, n (%)

Characteristics		Ca2+-first postoperative day		P value
		High group (> 1.975 mmol/L)	Low group (< 1.975 mmol/L)
n		179	101
Ethnic group				0.821
	Han ethnic group	149 (83.2)	83 (82.2)
	Others	30 (16.8)	18 (17.8)
Sex				0.693
	Female	77 (43.0)	41 (40.6)
	Male	102 (57.0)	60 (69.4)
Age (years)				0.012a
	< 65	121 (67.6)	53 (52.5)
	≥ 65	58 (32.4)	48 (47.5)
BMI				0.383
	< 23.5	65 (36.3)	42 (41.6)
	≥ 23.5	114 (63.7)	59 (58.4)
Tumor location				0.709
	Right half of colon	37 (22.6)	19 (15.1)
	Left half of colon	142 (77.4)	82 (84.9)
Degree of differentiation				0.018a
	High differentiation	24 (13.4)	3 (3.0)
	Moderately differentiated	127 (70.9)	80 (79.2)
	Poorly differentiated	28 (15.6)	18 (17.8)
T stage				0.313
	T1-2	39 (21.8)	21 (20.8)
	T3	106 (59.2)	53 (52.5)
	T4	34 (19.0)	27 (26.7)
N stage				0.907
	0	102 (54.7)	55 (52.3)
	N1	48 (45.3)	28 (47.7)
	N2	29 (16.2)	18 (17.8)
Neurovascular invasion				0.463
	No	133 (74.3)	79 (78.2)
	Yes	46 (25.7)	22 (21.8)
MSI				0.698
	MSS	164 (91.6)	94 (93.1)
	MSI-H	15 (8.4)	7 (6.9)
CEA (ug/L)				0.002a
	< 5	129 (72.1)	54 (53.5)
	≥ 5	50 (27.9)	47 (46.5)
CA19-9 (U/mL)				0.304
	< 39	158 (85.8)	90 (90.7)
	≥ 39	21 (14.2)	11 (9.3)
Hb (g/L)				0.753
	< 120	50 (27.9)	30 (29.7)
	≥ 120	129 (72.1)	71 (70.3)
PLT (109/L)				0.641
	< 330	143 (79.9)	83 (82.2)
	≥ 330	36 (20.1)	18 (17.8)
Alb (g/L)				0.175
	< 40	65 (36.3)	45 (44.6)
	≥ 40	114 (63.7)	56 (55.4)
Ca2+-baseline (mmol/L)				0.005a
	< 2.11	24 (7.5)	11 (9.3)
	≥ 2.11	155 (92.5)	90 (90.7)
δCa2+				< 0.001a
	< 0.245	145 (81.0)	28 (27.7)
	≥ 0.245	34 (19.0)	73 (72.3)

^aP < 0.05.

δCa²⁺: Delta serum calcium value; Alb: Albumin; BMI: Body mass index; CA19-9: Carbohydrate antigen 19-9; Ca²⁺-baseline: Baseline serum calcium ion levels; Ca²⁺-first postoperative day: Serum calcium ion level on the first day of postoperative period; CEA: Carcinoembryonic antigen; Hb: Hemoglobin; MSI: Microsatellite; PLT: Platelet.

Table 2 Correlation between clinical data variables and serum calcium ion levels on the first postoperative day

Relevant factor	Spearman’s correlation coefficient	P value
Age (years)	-0.253	< 0.001a
Sex	0.003	0.963
Ethnic group	-0.038	0.600
BMI	0.148	0.042a
CEA	-0.224	0.002a
CA19-9	-0.035	0.673
Hb	0.129	0.075
PLT	0.052	0.476
Alb	0.203	0.005a

^aP < 0.05.

Alb: Albumin; BMI: Body mass index; CA19-9: Carbohydrate antigen 19-9; CEA: Carcinoembryonic antigen; Hb: Hemoglobin; PLT: Platelet.

Table 3 Univariate and multivariate analyses of clinicopathological data in patients with colorectal cancer

Characteristics	Univariate analysis, HR (95%CI)	P value	Multivariate analysis, HR (95%CI)	P value
Ethnic group		0.610	-	-
Han ethnic group
Others	0.840 (0.429-1.643)
Sex		0.021a		0.031a
Female
Male	1.848 (1.097-3.115)		1.796 (1.056-3.054)
Age (years)		0.622	-	-
< 65
≥ 65	1.134 (0.688-1.867)
BMI (kg/m2)		0.448	-	-
< 23.5
≥ 23.5	0.830 (0.513-1.343)
Tumor location		0.387	-	-
Right half of colon
Left half of colon	1.330 (0.697-2.535)
Degree of differentiation		< 0.001a		0.047a
High differentiation
Moderately differentiated	3.250 (0.788-13.399)	0.103	2.056 (0.483-8.753)	0.330
Poorly differentiated	8.192 (1.920-34.960)	0.004a	3.717 (0.845-16.348)	0.082
T stage		< 0.001a		0.019a
T1-2
T3	3.272 (1.290-8.303)	0.013a	1.447 (0.518-4.037)	0.481
T4	5.820 (2.220-15.261)	< 0.001a	2.874 (1.034-7.985)	0.043a
N stage		< 0.001a		< 0.001a
0
N1	2.063 (1.150-3.702)	0.015a	1.321 (0.696-2.509)	0.394
N2	4.575 (2.564-8.164)	< 0.001a	3.407 (1.763-6.586)	< 0.001a
Neurovascular invasion		< 0.001a		0.037a
No
Yes	2.576 (1.588-4.178)		1.820 (1.036-3.196)
MSI		0.234
MSS
MSI-H	0.495 (0.156-1.575)
CEA (ng/mL)		< 0.001a		0.039a
< 5
≥ 5	2.398 (1.489-3.863)		1.709 (1.027-2.845)
CA19-9 (U/mL)		0.148
< 39
≥ 39	1.611 (0.844-3.073)
Hb (g/L)		0.389
< 120
≥ 120	0.800 (0.481-1.330)
PLT (109/L)		0.284
< 330
≥ 330	1.358 (0.776-2.379)
Alb (g/L)		0.636
< 40
≥ 40	0.890 (0.549-1.443)
Ca2+-baseline		0.042a		0.011a
< 2.11
≥ 2.11	3.326 (1.045-10.584)		4.762 (1.426-15.905)
Ca2+-first postoperative day		< 0.001a		0.006a
High
Low	2.234 (1.387-3.597)		2.315 (1.276-4.199)
δCa2+		0.010a		0.506
Low
High	1.876 (1.166-3.020)		0.820 (0.458-1.471)

^aP < 0.05.

δCa²⁺: Delta serum calcium; Alb: Albumin; BMI: Body mass index; CA19-9: Carbohydrate antigen 19-9; Ca²⁺-first postoperative day: Serum calcium ion level on the first day of postoperative period; CEA: Carcinoembryonic antigen; CI: Confidence interval; Hb: Hemoglobin; HR: Hazard ratio; MSI: Microsatellite; PLT: Platelet.