Body mass index predicts low muscle mass in esophageal squamous cell carcinoma patients undergoing chemoradiotherapy

Table 1 Participant baseline characteristics stratified by body mass index categories, n (%)

Characteristics	Overall (n = 360)	BMI			P value
		< 18.5 kg/m2 (n = 36)	18.5-24.0 kg/m2 (n = 239)	≥ 24.0 kg/m2 (n = 85)
Survival state					0.356
Survival	151 (41.9)	13 (3.6)	97 (26.9)	41 (11.4)
Death	209 (58.1)	23 (6.4)	142 (39.4)	44 (12.2)
Survive time, median (IQR)	22.2 (12, 38.78)	14.535 (7.7425, 34.793)	22 (12.2, 37.95)	26 (15, 41.57)	0.019
Gender					0.056
Female	73 (20.3)	6 (1.7)	42 (11.7)	25 (6.9)
Male	287 (79.7)	30 (8.3)	197 (54.7)	60 (16.7)
Age, mean ± SD	65 (58.75 ± 70)	65 (59.75 ± 72)	64 (57.5 ± 69)	66 (61 ± 71)	0.072
KPS					0.057
70	6 (1.7)	3 (0.8)	2 (0.6)	1 (0.3)
80	144 (40)	12 (3.3)	96 (26.7)	36 (10)
90	208 (57.8)	21 (5.8)	140 (38.9)	47 (13.1)
100	2 (0.6)	0 (0)	1 (0.3)	1 (0.3)
Smoking history					0.006
No	142 (39.4)	12 (3.3)	84 (23.3)	46 (12.8)
Yes	218 (60.6)	24 (6.7)	155 (43.1)	39 (10.8)
Alcohol history					0.331
No	153 (42.5)	17 (4.7)	95 (26.4)	41 (11.4)
Yes	207 (57.5)	19 (5.3)	144 (40)	44 (12.2)
Tumor location					0.956
Cervical	23 (6.4)	1 (0.3)	16 (4.4)	6 (1.7)
Upper thoracic	79 (21.9)	10 (2.8)	53 (14.7)	16 (4.4)
Middle thoracic	139 (38.6)	14 (3.9)	93 (25.8)	32 (8.9)
Lower thoracic	107 (29.7)	10 (2.8)	70 (19.4)	27 (7.5)
Abdominal	12 (3.3)	1 (0.3)	7 (1.9)	4 (1.1)
T stage					0.006
1	1 (0.3)	0 (0)	1 (0.3)	0 (0)
2	31 (8.6)	2 (0.6)	22 (6.1)	7 (1.9)
3	203 (56.4)	11 (3.1)	135 (37.5)	57 (15.8)
4	125 (34.7)	23 (6.4)	81 (22.5)	21 (5.8)
N stage					0.016
0	7 (1.9)	0 (0)	2 (0.6)	5 (1.4)
1	96 (26.7)	7 (1.9)	59 (16.4)	30 (8.3)
2	180 (50)	19 (5.3)	124 (34.4)	37 (10.3)
3	77 (21.4)	10 (2.8)	54 (15)	13 (3.6)
Clinical stage					0.001
I	1 (0.3)	0 (0)	1 (0.3)	0 (0)
II	16 (4.4)	2 (0.6)	7 (1.9)	7 (1.9)
III	206 (57.2)	10 (2.8)	140 (38.9)	56 (15.6)
IV	137 (38.1)	24 (6.7)	91 (25.3)	22 (6.1)
RT dose, median (IQR)	65 (60, 66)	61.2 (60, 66)	65 (60, 66)	66 (60, 66)	0.376
Chemotherapy					0.003
No	39 (10.8)	10 (2.8)	21 (5.8)	8 (2.2)
Yes	321 (89.2)	26 (7.2)	218 (60.6)	77 (21.4)
Glucose, median (IQR)	5.13 (4.71, 5.8225)	5.045 (4.5625, 5.76)	5.1 (4.71, 5.725)	5.26 (4.8, 6.1)	0.110
Total cholesterol, mean ± SD	4.725 (4.0475 ± 5.3625)	4.49 (4.1225 ± 5.3375)	4.79 (4.07 ± 5.365)	4.83 (3.88 ± 5.36)	0.921
Triglyceride, median (IQR)	1.13 (0.8975, 1.45)	1.025 (0.8375, 1.295)	1.12 (0.885, 1.4)	1.31 (1, 1.57)	0.017
LMM					< 0.001
No	277 (76.9)	12 (3.3)	185 (51.4)	80 (22.2)
Yes	83 (23.1)	24 (6.7)	54 (15)	5 (1.4)

BMI: Body mass index; IQR: Interquartile range; KPS: Karnofsky performance score; RT: Radiotherapy; LMM: Low muscle mass.

Table 2 Association between body mass index and low muscle mass

Characteristic	Model 1			Model 2			Model 3
	OR	95%CI	P value	OR	95%CI	P value	OR	95%CI	P value
BMI (continuous)	0.62	0.543-0.709	< 0.001	0.611	0.531-0.703	< 0.001	0.613	0.531-0.707	< 0.001
BMI (categorical)
< 18.5 kg/m2	Reference	Reference	-	Reference	Reference	-	Reference	Reference	-
18.5-24.0 kg/m2	0.146	0.075-0.361	< 0.001	0.165	0.075-0.361	< 0.001	0.159	0.078-0.379	< 0.001
≥ 24.0 kg/m2	0.031	0.00-0.098	< 0.001	0.031	0.009-0.101	< 0.001	0.032	0.010-0.107	< 0.001
P for trend	-	-	< 0.001	-	-	< 0.001	-	-	< 0.001

Model 1: Unadjusted; Model 2: Adjusted for age, gender, Karnofsky performance score, smoking history, alcohol history; Model 3: Age, gender, Karnofsky performance score, smoking history, alcohol history, tumor location, radiotherapy dose, chemotherapy, T stage, N stage, glucose, total cholesterol, triglyceride. OR: Odds ratio; CI: Confidence interval; BMI: Body mass index.

Table 3 Associations between body mass index and all-cause mortality in participants with sarcopenia

Characteristic	Model 1			Model 2			Model 3
	HR	95%CI	P value	HR	95%CI	P value	HR	95%CI	P value
BMI (continuous)	0.923	0.879-0.970	0.001	0.94	0.891-0.992	0.023	0.941	0.892-0.993	0.025
BMI (categorical)
18.5 kg/m2	Reference	Reference	-	Reference	Reference	-	Reference	Reference	-
18.5-24.0 kg/m2	0.732	0.471-1.138	0.166	0.783	0.495-1.239	0.296	0.732	0.471-1.138	0.446
≥ 24.0 kg/m2	0.574	0.346-0.951	0.031	0.583	0.346-0.984	0.043	0.574	0.346-0.951	0.047
P for trend	-	-	< 0.001	-	-	0.017	-	-	0.02

Model 1: Unadjusted; Model 2: Adjusted for age, gender, Karnofsky performance score, smoking history, alcohol history; Model 3: Age, gender, Karnofsky performance score, smoking history, alcohol history, tumor location, radiotherapy dose, chemotherapy, T stage, N stage, glucose, total cholesterol, triglyceride. HR: Hazard ratio; BMI: Body mass index; CI: Confidence interval.