Multivariate predictive model for asymptomatic spontaneous bacterial peritonitis in patients with liver cirrhosis

Table 1 Demographic characteristics of the study population

Parameters	Patients (n = 343, %)
Age (yr)	54.60 ± 12.79
Gender
Male	259 (75.51)
Female	84 (24.49)
Clinical characteristics
Etiology of cirrhosis
Viral hepatitis	220 (64.14)
Alcohol	65 (18.95)
Autoimmune	27 (7.87)
Others	31 (9.04)
Child-Pugh
A	19 (5.54)
B	175 (51.02)
C	149 (43.44)
MELD score	12.04 ± 8.87
Complications
Liver failure	51 (14.87)
HCC	64 (18.66)
HE	29 (8.45)
Diabetes	68 (19.82)
Renal dysfunction	68 (19.82)
UGB	22 (6.41)
Hematological factors
WBC (× 109/L)	5.19 ± 3.62
N (100%)	0.64 ± 0.12
PLT (× 109/L)	89.93 ± 60.52
WBC/PLT	0.082 ± 0.013
Ascites examinations
Leukocyte (mm3)	258.92 ± 247.46
Polymorphonuclear (100%)	0.10 ± 0.098
PMN (mm3)	28.22 ± 39.46
Microbiological examinations
Positive	111 (32.36)
Gram-negative	21 (18.92)
Gram-positive	80 (72.07)
Mixture	10 (9.01)
Negative	232 (67.64)
Clinical outcomes
Non-survivors	37 (10.79)
Improved	297 (86.59)
Invalid	9 (2.62)

CHILD: Child-Pugh; MELD: Model for end-stage liver disease; HCC: Hepatocellular carcinoma; HE: Hepatic encephalopathy; UGB: Upper gastrointestinal bleeding; WBC: White blood cell count; N: Blood neutrophil percentage; PLT: Platelet; PMN: Polymorphonuclear leukocyte count in ascites.

Table 2 Comparisons between asymptomatic spontaneous bacterial peritonitis and control groups

Characteristics	Asymptomatic SBP (n = 98, %)	Control group (n = 98, %)	P value
Age (yr)	54.01 ± 13.60	53.56 ± 13.47	0.817
Gender			0.178
Male	79 (80.61)	71 (72.45)
Female	19 (19.39)	27 (27.55)
Clinical characteristics
Etiology of cirrhosis			0.280
Viral hepatitis	70 (71.43)	61 (62.24)
Alcohol	16 (16.33)	19 (19.39)
Autoimmune	5 (5.10)	12 (12.24)
Others	7 (7.14)	6 (6.12)
Child-Pugh			0.004
A	2 (2.04)	2 (2.04)
B	35 (35.71)	58 (59.18)
C	61 (62.24)	38(38.78)
MELD score	18.20 ± 11.04	9.92 ± 5.88	< 0.001
Complications
Liver failure	28 (28.57)	7 (7.14)	< 0.001
HCC	37 (37.75)	10 (10.20)	< 0.001
HE	21 (21.43)	3 (3.06)	< 0.001
Diabetes	22 (22.45)	13 (13.26)	0.093
Renal dysfunction	39 (39.80)	10 (10.20)	< 0.001
UGB	19 (19.39)	0 (0.00)	< 0.001
Hematological factors
WBC (× 109/L)	7.25 ± 4.66	3.97 ± 1.99	< 0.001
N (100%)	0.71 ± 0.13	0.60 ± 0.13	0.007
PLT (×109/L)	92.08 ± 71.37	82.44 ± 43.27	0.244
WBC/PLT	0.14 ± 0.22	0.057 ± 0.04	0.001
Ascites examinations
Leukocyte (/mm3)	314.41 ± 351.67	254.08 ± 231.51	0.151
Polymorphonuclear (100%)	0.15 ± 0.12	0.086 ± 0.10	< 0.001
PMN (/mm3)	45.83 ± 52.25	21.44 ± 28.71	< 0.001
Clinical outcomes
Non-survivors	33 (33.67)	3 (3.06)	< 0.001

SBP: Spontaneous bacterial peritonitis; CHILD: Child-Pugh; MELD: Model for end-stage liver disease; HCC: Hepatocellular carcinoma; HE: Hepatic encephalopathy; UGB: Upper gastrointestinal bleeding; WBC: White blood cell count; N: Neutrophil percentage; PLT: Platelet; PMN: Polymorphonuclear leukocyte count in ascites.

Table 3 Receiver operating characteristic analysis for the continuous variables in 196 selected patients

Variables	AUC	Cut-off value
Age (yr)	0.489	71.50
MELD score	0.733	15.50
WBC (× 109/L)	0.729	4.73
N (100%)	0.747	0.6615
PLT (× 109/L)	0.494	187.50
WBC/PLT	0.720	0.0619
Leukocyte (mm3)	0.538	230.00
Polymorphonuclear (100%)	0.683	0.075
PMN (mm3)	0.671	10.95

AUC: Area under curve; MELD: Model for end-stage liver disease; WBC: White blood cell count; N: Blood neutrophil percentage; PLT: Platelet; PMN: Polymorphonuclear leukocyte count in ascites.

Table 4 Multiple linear stepwise regression analysis of the candidate indicators for asymptomatic spontaneous bacterial peritonitis

Parameters	Unstandardized Coefficients		Standardized Coefficients	t	P value
	B	Std. Error	Beta
Constant	0.018	0.055		0.331	0.741
MELD	0.312	0.064	0.299	4.901	0.000
PMN	0.263	0.059	0.252	4.474	0.000
N	0.184	0.062	0.183	2.963	0.003
HCC	0.233	0.067	0.199	3.480	0.001
Renal dysfunction	0.189	0.071	0.164	2.671	0.008

SBP: Spontaneous bacterial peritonitis; MELD: Model for end-stage liver disease; HCC: Hepatocellular carcinoma; N: Blood neutrophil percentage; PMN: Polymorphonuclear leukocyte count in ascites.

Table 5 Predictive results of the constructed model in the original study population

Predictive results	Observed results		Percentage correct
	Asymptomatic SBP	Control group
Asymptomatic SBP	72	26	73.5%
Control group	13	85	86.7%

SBP: Spontaneous bacterial peritonitis.