Growth differentiation factor-15 serum concentrations reflect disease severity and anemia in patients with inflammatory bowel disease

Table 1 Baseline characteristics of the studied population

Parameter	Control group (n = 67)	IBD group (n = 90)	P value1
Age, yr	38.5 ± 12.3	41.2 ± 15.8	0.195
Male sex, n (%)	43 (64.2)	53 (58.9)	0.503
Body mass index, kg/m2	24.7 ± 2.8	23.8 ± 4.2	0.070
Waist-to-hip ratio	0.91 ± 0.36	0.87 ± 0.08	0.368
Hypertension, n (%)	1 (1.5)	6 (6.7)	0.122
Dyslipidemia, n (%)	2 (3.0)	7 (7.8)	0.203
Family history of IBD, n (%)	3 (4.5)	16 (17.8)	0.012
Family history of CRC, n (%)	9 (13.4)	17 (18.9)	0.365
Family history of CVD, n (%)	31 (46.3)	29 (32.2)	0.074
Smoking, n (%)	12 (18.5)	17 (18.9)	0.947
C-reactive protein, mg/L	0.7 (0.4-1.6)	1.6 (0.7-3.8)	< 0.001
Serum iron, μmol/L	18.1 ± 6.7	15.2 ± 7.8	0.009
Albumins, g/L	43.9 ± 2.5	40.4 ± 4.9	< 0.001
Serum urate levels, mmol/L	296.1 ± 76.0	275.5 ± 70.9	0.064
Fasting blood glucose, mmol/L	5.1 ± 0.7	5.2 ± 1.6	0.691
Total cholesterol, mmol/L	5.2 ± 1.2	4.7 ± 1.3	0.008
LDL-C, mmol/L	3.3 ± 1.1	2.7 ± 1.1	< 0.001
HDL-C, mmol/L	1.4 ± 0.3	1.4 ± 0.4	0.409
Triglycerides, mmol/L	1.2 ± 0.6	1.4 ± 1.1	0.158

¹Welch’s t-test, Mann-Whitney U test or chi squared test, as appropriate.

Data presented as mean ± SD, median (IQR) or n (%). CRC: Colorectal carcinoma; CVD: Cardiovascular disease; HDL-C: High-density lipoprotein cholesterol; IBD: Inflammatory bowel disease; LDL-C: Low-density lipoprotein cholesterol.

Table 2 Basic anthropometric and disease characteristics of ulcerative colitis and Crohn’s disease group

Parameter	Crohn’s disease (n = 48)	Ulcerative colitis (n = 42)	P value1
Basic characteristics
Age, yr	40.7 ± 16.0	42.7 ± 15.9	0.567
Male sex, n (%)	31 (64.6)	22 (52.4)	0.243
Body mass index, kg/m2	23.2 ± 3.6	23.9 ± 4.9	0.459
Waist-to-hip ratio	0.86 ± 0.08	0.86 ± 0.08	0.495
Hypertension, n (%)	2 (4.2)	4 (9.5)	0.312
Dyslipidemia, n (%)	3 (6.2)	4 (9.5)	0.565
Family history of IBD, n (%)	10 (20.8)	6 (14.3)	0.420
Family history of CRC, n (%)	10 (20.8)	7 (16.7)	0.616
Family history of CVD, n (%)	12 (28.6)	17 (35.4)	0.491
Smoking, n (%)	16 (33.3)	1 (2.4)	< 0.001
Laboratory parameters
C-reactive protein, mg/L	1.9 (0.6-7.6)	1.4 (0.8-2.2)	0.153
Serum iron, μmol/L	14.6 ± 7.6	16.5 ± 7.9	0.247
Albumins, g/L	39.5 ± 5.5	41.6 ± 3.6	0.018
Fasting blood glucose, mmol/L	4.9 ± 0.8	5.6 ± 2.5	0.100
Total cholesterol, mmol/L	4.4 ± 1.2	5.1 ± 1.3	0.005
LDL-C, mmol/L	2.3 ± 0.9	3.1 ± 1.1	< 0.001
HDL-C, mmol/L	1.3 ± 0.4	1.4 ± 0.4	0.045
Triglycerides, mmol/L	1.7 ± 1.5	1.2 ± 0.7	0.079
Disease characteristics
Disease duration, yr	7 (3-14)	9 (5-13)	0.397
IBD-related surgery, n (%)	20 (41.7)	0 (0.0)	< 0.001
ExtraintestiN/Al manifestations, n (%)	27 (56.3)	7 (16.7)	< 0.001
SES-CD	10 (5-13)	N/A	N/A
CDAI	55 (34-84)	N/A	N/A
UCEIS	N/A	5.0 (1.5-6.5)
Mayo/DAI	N/A	3 (2-5)	N/A
Fecal calprotectin, μg/g	232 (80-589)	85 (10-246)	0.009
Therapy, n (%)
Aminosalicylates	22 (45.8)	23 (54.8)	0.421
DMARDs	18 (37.5)	17 (40.5)	0.826
MonocloN/Al antibodies	36 (75.0)	32 (76.2)	0.896

¹Welch’s t-test, Mann-Whitney U test or chi squared test, as appropriate.

Data presented as mean ± SD, median (IQR) or n (%). CDAI: Crohn’s disease activity index; CRC: Colorectal carcinoma; CVD: Cardiovascular disease; DMARD: Disease-modifying anti-rheumatic drugs; HDL-C: High-density lipoprotein cholesterol; IBD: Inflammatory bowel disease; LDL-C: Low-density lipoprotein cholesterol; Mayo/DAI: Mayo score/disease activity index; SES-CD: Simple endoscopic score for Crohn’s disease; UCEIS: Ulcerative colitis endoscopic index of severity; N/A: Not applicable.

Table 3 Comparison of serum growth-differentiation factor-15 concentrations between the study groups

Parameter	Study groups		P value1
GDF-15, pg/mL	Control group (n = 67)	IBD group (n = 90)
	412 (407-424)	800 (512-1154)	< 0.001
	Crohn’s disease (n = 48)	Ulcerative colitis (n = 42)
	807 (554-1451)	790 (509-956)	0.324

¹Mann-Whitney U test. Data are presented as median (interquartile range).

GDF-15: Growth-differentiation factor-15; IBD: Inflammatory bowel disease.

Table 4 Correlation analysis between growth-differentiation factor-15 and various anthropometric and laboratory variables

Parameter	r-correlation coefficient1	P value
Age, yr	0.117	0.145
Albumins	-0.338	< 0.001
Fecal calprotectin2	0.143	0.178
Fasting glucose	0.021	0.796
Total cholesterol	-0.196	0.014
LDL-cholesterol	-0.216	0.007
Waist-to-hip ratio	-0.044	0.584

¹Spearman’s rank correlation coefficient.

²Measured only in patients with inflammatory bowel disease.

IBD: Inflammatory bowel disease; LDL-cholesterol: Low-density lipoprotein cholesterol.