Altered metabolism of bile acids correlates with clinical parameters and the gut microbiota in patients with diarrhea-predominant irritable bowel syndrome

Table 1 Demographics and clinical characteristics of patients with diarrhea-predominant irritable bowel syndrome and healthy controls

Features	IBS-D patients	Controls	P value
n	55	28	NA
Age in yr	35.1 ± 9.8	34.4 ± 10.6	0.754
Gender, male: Female	41: 14	5: 2	0.761
Body mass index in kg/m2	23.3 ± 3.4	22.6 ± 3.1	0.335
Duration of disease in yr	3.0 (1.5, 7.0)	NA	NA
Defecation frequency	3.5 (2.5, 4.0)	1.0 (0.7, 1.0)	< 0.001
BSFS score	5.5 (5.0, 6.0)	4.0 (4.0, 4.0)	< 0.001
IBS-SSS	180.0 (150.0, 240.0)	NA	NA
Abdominal pain severity	40.0 (20.0, 50.0)	NA	NA
Abdominal pain frequency	30.0 (20.0, 40.0)	NA	NA
Abdominal bloating	10.0 (0.0, 20.0)	NA	NA
Bowel habit dissatisfaction	60.0 (60.0, 70.0)	NA	NA
Overall interference with QOL	30.0 (30.0, 50.0)	NA	NA
HADS anxiety score	5.0 (3.0, 10.0)	2.0 (0.0, 3.8)	< 0.001
HADS depression score	4.0 (1.0, 7.0)	1.5 (0.0, 3.8)	0.009
VSI score	30.0 (19.0, 42.0)	4.0 (0.0, 13.3)	< 0.001

The data are presented as the mean ± SD or the median (Q1, Q3). BSFS: Bristol stool form scale; HADS: Hospital anxiety and depression scale; IBS-D: Irritable bowel syndrome with predominant diarrhea; IBS-SSS: Irritable bowel syndrome symptom severity scale; NA: Not applicable; QOL: Quality of life; VSI: Visceral sensitivity index.

Table 2 Visceral sensation thresholds in patients with diarrhea-predominant irritable bowel syndrome and healthy controls

Visceral sensation threshold in mL	IBS-D patients, n = 23	Controls, n = 15	P value
First sensation threshold	40 (20, 50)	40 (35, 60)	0.235
Defecating sensation threshold	60 (50, 85)	70 (65, 100)	0.073
Maximum sensation threshold	105 (90, 120)	160 (145, 190)	< 0.001

The data are expressed as median (Q1, Q3). IBS-D: Irritable bowel syndrome with predominant diarrhea.

Table 3 Levels of fecal bile acids in patients with diarrhea-predominant irritable bowel syndrome and controls

Bile acids in nmol/g	IBS-D patients, n = 55	Controls, n = 28	P value
CA	3037.66 (282.82, 6917.47)	20.19 (5.03, 1304.28)	< 0.001
CDCA	1721.86 (352.80, 2613.83)	57.16 (13.76, 1639.92)	< 0.001
DCA	2012.66 (232.57, 2659.34)	2159.78 (1676.03, 3094.08)	0.084
LCA	1621.65 (58.99, 2396.49)	2339.24 (1737.09, 2782.40)	0.002
UDCA	8.92 (2.33, 23.93)	17.21 (8.76, 33.48)	0.025
TCA	5.36 (0.62, 26.39)	0.72 (0.46, 2.11)	0.004
TCDCA	6.85 (1.54, 22.89)	1.41 (0.37, 3.58)	0.001
TDCA	1.53 (0.93, 8.08)	1.75 (0.86, 6.63)	1.000
TLCA	0.88 (0.57, 1.85)	1.03 (0.36, 2.80)	0.908
TUDCA	1.43 (0.68, 2.61)	0.37 (0.07, 1.23)	0.002
GCA	4.36 (2.31, 17.52)	2.23 (1.39, 3.55)	< 0.001
GCDCA	17.47 (5.61, 51.56)	5.17 (2.56, 10.51)	< 0.001
GDCA	3.32 (0.63, 10.63)	2.67 (1.44, 6.83)	0.867
GLCA	0.64 (0.39, 1.61)	0.91 (0.41, 1.28)	0.282
GUDCA	1.27 (0.56, 4.76)	0.65 (0.38, 0.87)	0.002
Total BAs	8227.35 (5218.49, 12464.03)	5220.28 (3971.35, 8272.29)	0.011
Unconjugated BAs	8197.73 (5135.49, 11622.72)	5183.71 (3945.65, 8253.23)	0.017
Conjugated BAs	55.28 (27.09, 198.08)	28.51 (9.68, 36.32)	0.002
Tauro-BAs	23.00 (5.03, 58.65)	6.34 (2.52, 18.05)	0.006
Glyco-BAs	28.03 (13.20, 69.07)	12.77 (6.18, 23.15)	< 0.001
CBA/UBA ratio	0.0080 (0.0036, 0.0172)	0.0035 (0.0019, 0.0058)	0.004
Primary BAs	5534.22 (672.24, 10546.54)	85.88 (27.08, 3197.10)	< 0.001
Secondary BAs	3759.10 (336.36, 4694.96)	4675.59 (3543.60, 5623.73)	0.009
PBA/SBA ratio	1.66 (0.22, 11.14)	0.02 (0.01, 0.57)	< 0.001

The bile acids data are presented as the median (Q1, Q3). The P value after FDR correction was presented in the table. BAs: Bile acids; CA: Cholic acid; CBA/UBA ratio: The ratio of conjugated BAs to unconjugated BAs; CDCA: Chenodeoxycholic acid; DCA: Deoxycholic acid; GCA: Glyco-cholic acid; GCDCA: Glyco-chenodeoxycholic acid; GDCA: Glyco-deoxycholic acid; GLCA: Glyco-lithocholic acid; GUDCA: Glyco-ursodeoxycholic acid; IBS-D: Irritable bowel syndrome with predominant diarrhea; LCA: Lithocholic acid; PBA/SBA ratio: The ratio of primary BAs to secondary Bas; TCA: Tauro-cholic acid; TCDCA: Tauro-chenodeoxycholic acid; TDCA: Tauro-deoxycholic acid; TLCA: Tauro-lithocholic acid; TUDCA: Tauro-ursodeoxycholic acid; UDCA: Ursodeoxycholic acid.