Bile acid indices as biomarkers for liver diseases II: The bile acid score survival prognostic model

Table 1 Patient population characteristics

	Patients	Death	Liver transplant
n	257	27	25
Gender
Male	136	21	17
Female	121	6	8
Age (yr)
mean ± SE	52.2 ± 0.71	55.9 ± 1.88	52.9 ± 2.1
Body mass index
mean ± SE	30.7 ± 0.45	29.65 ± 1.19	29.11 ± 0.45
Race
White	217	26	24
Black	11	0	0
Asian	7	0	0
Hispanic	4	0	1
Others	18	1	0
Non-BA parameters (mean ± SE)
Creatinine (mg/dL)	1.02 ± 0.09
Albumin (g/dL)	3.53 ± 0.04
INR	1.19 ± 0.02
Protime (s)	12.01 ± 0.42
AST (U/L)	59.9 ± 4.07
ALT (U/L)	54.9 ± 4.26
Bilirubin (mg/dL)	1.75 ± 0.15
AST/ALT	1.28 ± 0.04
MELD	10.6 ± 0.34
APRI	1.15 ± 0.11

BA: Bile acids; INR: International normalized ratio; AST: Aspartate aminotransferase; ALT: Alanine aminotransferase; MELD: Model for end-stage liver disease; APRI: Aspartate aminotransferase/platelet ratio index.

Table 2 Multivariate Cox regression analysis for death prediction

BA indices (%) and non-BA parameters	B-value (regression coefficient)	Standard error	P value	Hazard ratio: Exp (B)
				1 unit change	10% change	20% change
The BAS model
%CDCA	0.039	0.010	0.000	1.040	1.159	1.344
%Tri-OH	0.052	0.016	0.001	1.053	1.069	1.142
The non-BAS model
AST/ALT	1.236	0.303	0.000	3.442	1.165	1.357

Using the regression coefficients from this table: The bile-acids score (BAS) equation is: the non-BAS equation is: BAS: Bile acids score; AST: Aspartate aminotransferase; ALT: Alanine aminotransferase.

Table 3 Receiver operating characteristics analysis of bile-acids score, non- bile-acids score, and models for end stage liver diseases for death prediction

Models	AUC (5-yr)	AUC (3-yr)	(Cutoff value; sensitivity, specificity)
BAS	0.740	0.761	(2.71; 74, 68)
non-BAS	0.653	0.664	(1.72; 67, 66)
MELD	0.683	0.715	(10; 62, 64)

AUC: Areas under the ROC curve; BAS: Bile acids score; MELD: Model for end-stage liver disease.

Table 4 Estimated survival probability [S₀ (t)] for death prediction

t (mo)	5	7	14	24	36	60	76
The BAS
S0 (t)	0.993	0.985	0.971	0.948	0.934	0.916	0.901
The non-BAS
S0 (t)	0.989	0.978	0.958	0.924	0.902	0.876	0.855

BAS: Bile acids score.

Table 5 Kaplan-Meier analysis for survival

Cutoff	Total n	n of events	Estimated mean (mo)	Standard error	95%CI
BAS
Median cutoff of 2.19
Low risk < 2.19	128	4	81.68	1.14	79.44-83.93
High risk > 2.19	129	23	70.72	2.5	65.81-75.62
Non-BAS
Median cutoff of 1.44
Low risk < 1.44	118	9	78.68	1.70	75.34-82.02
High risk > 1.44	139	18	73.97	2.21	69.64-78.29
MELD
Median cutoff of 11
Low risk < 11	133	11	78.06	1.71	74.71-81.42
High risk > 11	124	16	73.91	2.35	69.29-78.52

BAS: Bile acids score; MELD: Model for end-stage liver disease.