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Impact of body mass index and viral load on liver histology in hepatitis B e antigen-negative chronic hepatitis B
Clinical Nutrition 30 (2011) 647e652
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Clinical Nutrition journal homepage: http://www.elsevier.com/locate/clnu
Original article
Impact of body mass index and viral load on liver histology in hepatitis B e antigen-negative chronic hepatitis B I-Cheng Lee a, b, Yi-Hsiang Huang a, b, *, Che-Chang Chan a, b, Teh-Ia Huo b, c, Chi-Jen Chu b, Chiung-Ru Lai d, Pui-Ching Lee b, Chien-Wei Su a, b, Jaw-Ching Wu a, e, Han-Chieh Lin b, Shou-Dong Lee b a
Institute of Clinical Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan Division of Gastroenterology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan Institute of Pharmacology, National Yang-Ming University School of Medicine, Taipei, Taiwan d Department of Pathology, Taipei Veterans General Hospital, Taipei, Taiwan e Department of Medical Research and Education, Taipei Veterans General Hospital, Taipei, Taiwan b c
a r t i c l e i n f o
s u m m a r y
Article history: Received 26 October 2010 Accepted 2 May 2011
Background & aims: The impact of overweight and obesity on chronic hepatitis B (CHB) is unclear. This study was to examine the relationship among body mass index, viral load and liver histology in HBeAgnegative CHB. Methods: The study retrospectively investigated 136 HBeAg-negative chronic hepatitis B patients who had undergone liver biopsies in Taiwan. Factors associated with significant liver histology were analyzed. Definitions of overweight and obesity for the Asian population were body mass index 23 kg/m2 and 25 kg/m2, respectively. Results: The prevalence of overweight, obesity, and type 2 diabetes mellitus in the 136 patients were 22.8%, 52.2%, and 12.5%, respectively. Multivariate analysis identified obesity, AST > 40 U/L, HBV DNA > 20,000 IU/mL and platelet count < 150 109/L as independent factors associated with significant liver fibrosis. Similarly, overweight/obesity, ALT > 80 U/L, HBV DNA > 1,000,000 IU/mL, and platelet count < 150 109/L were independent predictors of significant hepatic necro-inflammation. By stratification, high BMI and high viral load patients had more advanced stage and grade of liver histology. Conclusions: Body mass index and HBV viral loads may have synergistic effect on disease progression in HBeAg-negative CHB. Both controlling body weight and anti-viral therapy are important in the management of CHB. Ó 2011 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.
Keywords: Body mass index Chronic hepatitis B Hepatitis B e antigen-negative Hepatitis B virus Liver histology Obesity
1. Introduction Obesity remains a growing public health concern and its prevalence is increasing at an alarming rate worldwide.1 Multiple studies have documented the adverse health consequences of overweight and obesity, including diabetes mellitus (DM), coronary heart disease, certain forms of cancer, and increased mortality from
Abbreviations: BMI, body mass index; HBeAg, hepatitis B e antigen; CHB, chronic hepatitis B; OR, odds ratio; DM, diabetes mellitus; ALT, alanine aminotransferase; NAFLD, non-alcoholic fatty liver disease; HCC, hepato-cellular carcinoma; CHC, chronic hepatitis C; HBV, hepatitis B virus; HIV, human immunodeficiency virus; HBsAg, hepatitis B surface antigen; AST, aspartate aminotransferase; INR, international normalized ratio. * Corresponding author. Division of Gastroenterology, Department of Medicine, Taipei Veterans General Hospital, 201 Shih-Pai Road, Sec. 2, Taipei 112, Taiwan. Tel.: þ886 2 28712121x3055; fax: þ886 2 28739318. E-mail address: [email protected] (Y.-H. Huang).
all cause.2 The adverse impact of obesity on the liver contributes to the development of hepatic steatosis, non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steato-hepatitis.3 Obesity also reportedly correlates with increased risk of cirrhosis-related death or hospitalization,4 as well as the development of hepato-cellular carcinoma (HCC).5 It is well known that obesity and metabolic factors play important roles in the progression and response to anti-viral therapy in chronic hepatitis C (CHC).6 Weight loss alone in CHC patients is associated with a reduction in steatosis and improvement in liver enzymes and liver fibrosis.7 Moreover, control of metabolic factors and attempts to lose weight are suggested for such patients because weight reduction and improvement in insulin resistance may improve the response to anti-hepatitis C virus (HCV) therapy.8 In Taiwan, hepatitis B virus (HBV) infection is the most important etiology of chronic liver disease.9 Several factors are associated
0261-5614/$ e see front matter Ó 2011 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved. doi:10.1016/j.clnu.2011.05.001
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I.-C. Lee et al. / Clinical Nutrition 30 (2011) 647e652
with CHB disease progression, including age, sex, immune status, viral load, HBV genotype, concurrent HCV or human immunodeficiency virus (HIV) infection, and several environmental exposures.10 In CHB patients, obesity is associated with elevated ALT activity.11 Those with metabolic syndrome carry a higher risk of liver stiffness.12 Obesity is also independently associated with HCC development in HBV carriers.13 In general, after hepatitis B e antigen (HBeAg) sero-conversion, 10e30% of patients may develop HBeAg-negative CHB, in whom HBV DNA replicates and the disease progresses.14 HBeAg-negative CHB represents a unique phase in the natural history of chronic HBV infection.15 These patients tend to be older, have more advanced liver disease, and have more evidence of long-term adverse effects of obesity. Treatment remains a clinical challenge and it may be beneficial to identify a correctable metabolic factor with impact on the progression of CHB. The relationship between body mass index (BMI) and liver histology in HBeAg-negative CHB has not been well studied. This study aimed to evaluate the association of BMI with hepatic fibrosis and necro-inflammation in HBeAg-negative CHB. 2. Materials and methods
the Study of Liver Disease (AASLD) treatment guidelines.17 None received anti-viral treatment (nucleoside/nucleotide analogues or interferon) before liver biopsy. The exclusion criteria were (1) HCV, hepatitis D virus, or HIV coinfection, (2) anti-nuclear antibody titer 1:160, positive test for anti-smooth muscle antibody or anti-mitochondrial antibody, (3) use of hepatotoxic drug or Chinese herb, (4) alcoholic liver disease, and (5) radiologic evidence of HCC (i.e., abdominal sonogram, computed tomography scan, or magnetic resonance imaging scans). Of the 330 CHB patients, 233 were HBeAg-negative. Twenty-five patients were excluded, including 8 with HCV co-infection, 8 with history of drug or herb use, 8 with HCC, and 1 who tested positive for ANA. Fifty-six patients did not have HBV DNA data within two weeks of liver biopsy and sixteen had HBV DNA level < 2000 IU/mL. The remaining 136 patients were enrolled (Fig. 1). Their clinical features, biochemical data, HBV viral loads within 2 week of liver biopsy, and medical history of type 2 DM were recorded. According to the World Health Organization guidelines for adult Asian population, BMI was categorized as normal (BMI < 23 kg/m2), overweight (BMI 23 kg/m2 but <25 kg/m2), or obese (BMI 25 kg/ m2).18 The institutional review board of Taipei Veterans General Hospital, Taipei, Taiwan approved the study.
2.1. Patients
2.2. Liver histology evaluation
Before November 2009, regulations of the Bureau of National Health Insurance, Taiwan, required that liver biopsy be performed to determine the necessity of anti-viral therapy for patients with HBeAg-negative CHB. From July 2006 to October 2009, 330 consecutive, treatment-naïve CHB patients who underwent liver biopsy at the Taipei Veterans General Hospital were screened.16 Among them, 233 were negative for HBeAg. The inclusion criteria were as follows: positive test for serum hepatitis B surface antigen (HBsAg) and negative test for HBeAg for at least six months, elevated serum ALT level (40 U/L, 1 upper limit of the normal range) recorded at least 2 distinct instances at an interval of one month, and HBV DNA level > 2000 IU/mL (tested using Cobas Amplicor HBV monitor, which has a detection limit of 12 IU/mL). Anti-viral treatment for all enrolled patients followed the American Association for
Liver tissue was obtained via ultrasound-guided percutaneous biopsy using a Tru-Cut needle (18G, Cardinal Health, McGaw Park, IL). All of the specimens were at least 1.5 cm in length. The average number of portal tracts in the biopsy specimens was 10.3 (range 7e14). Histological grading of the necro-inflammation and staging of the liver fibrosis were done according to the Ishak scoring system.19 Necro-inflammation was graded from 0 to 18, while fibrosis was staged from 0 to 6. According to the definition by Papatheodoridis et al., significant necro-inflammation was defined as grade 7 and significant fibrosis as stage 2 as per Ishak’s classification system.20,21 Hepatic steatosis was graded according to the Brunt classification: 0 (no hepatocytes involved with macro-vesicular steatosis), 1 (0e33% involved), 2 (33e66% involved) and 3 (>66% involved).22 A
Fig. 1. Profile of the study patients and their categorization based on body mass index and liver histology.
I.-C. Lee et al. / Clinical Nutrition 30 (2011) 647e652
single pathologist blinded to clinical information of the patients performed the pathology examinations of all liver biopsy specimens. 2.3. Liver biochemistry and viral serology tests Serum biochemical studies were performed using a systemic multi-auto-analyzer (Technicon SMAC, Technicon Instruments Corp., Tarrytown, NY). Serum samples were tested for the presence of HBsAg, HBeAg, and anti-HBeAg antibody using radioimmunoassay (Abbott Laboratories, North Chicago, IL), while a Cobas Amplicor HBV monitor determined the HBV DNA. 2.4. Statistical analysis All statistical analyses were performed using the Statistical Package for Social Sciences (SPSS 17.0 for Windows, SPSS Inc., Chicago, IL). Pearson chi-square analysis or Fisher exact test was used to compare categorical variables, while the Student t test or one-way ANOVA was used for group comparisons of parametric quantitative data. The ManneWhitney U or KruskaleWallis test was used for similar comparisons of non-parametric data. Variables with p < 0.1 were analyzed by multivariate logistic regression analysis to identify independent variables for predicting liver histology. The best cut-off value of each variable was determined by the receiver-operating characteristic curve using MedCalc (version 4.20, MedCalc Software, Mariakerke, Belgium). A twotailed p < 0.05 was considered statistically significant.
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3. Results 3.1. Patient characteristics The baseline characteristics of the 136 patients and those with and without significant liver fibrosis (Ishak stage 2) or significant liver necro-inflammation (Ishak grade 7) were summarized in Table 1. Their mean age was 50.9 years and mean BMI was 25.3 kg/m2. Ninety-nine (72.8%) were males. Thirty-one (22.8%) patients were overweight, 71 (52.2%) had obesity, and 17 (12.5%) had type 2 DM. There was hepatic steatosis in 85 (62.5%) patients, including 67 (49.3%) grade 1, 10 (7.4%) grade 2, and eight (5.9%) grade 3. The histological features in all CHB patients with steatosis were still viral hepatitis predominant. Sixty-four (47.1%) had significant liver fibrosis, including six patients (4.4%) with cirrhosis, and 35 (25.7%) had significant necro-inflammation (Fig. 1). Patients with significant liver fibrosis were older, had higher prevalence of type 2 DM, higher ALT and aspartate aminotransferase (AST) levels, longer pro-thrombin times measured by international normalized ratio (INR), lower platelet counts, and greater Ishak necro-inflammatory grade. Patients with significant necroinflammation were older, had higher ALT and AST levels, longer pro-thrombin times, lower WBC and platelet counts, higher HBV DNA levels, and greater Ishak fibrosis score. Patients who presented with hepatic steatosis had significantly higher BMI (25.9 vs. 23.6 kg/m2, p < 0.001). However, the presence or absence of hepatic steatosis was not correlated with HBV DNA levels (9.6 107 vs. 4.9 107 IU/mL, p ¼ 0.205).
Table 1 Baseline characteristics of HBeAg-negative chronic hepatitis B patients (n ¼ 136). Characteristic
Demographics Age (years) Male gender BMI (kg/m2) Type 2 DM Biochemical markers ALT (U/L) AST (U/L) Total bilirubin (mg/dL) Pro-thrombin time (INR) WBC (/cumm) Hemoglobin (g/dL) Platelet (109/L) Creatinine (mg/dL) HBV DNA (IU/mL) Histology Ishak necro-inflammatory grade Ishak fibrosis score Steatosis grade
All (n ¼ 136)
Ishak fibrosis stage
p Value
<2 (n ¼ 72)
2 (n ¼ 64)
50.9 12.4
48.1 11.6
54.0 12.6
99 (72.8%) 25.03 3.01
55/72 (76.4%) 24.75 2.92
17 (12.5%)
Ishak necro-inflammatory grading
p Value
<7 (n ¼ 101)
7 (n ¼ 35)
0.003
48.8 12.2
56.8 11.1
0.001
44/64 (68.8%) 25.35 3.11
0.420 0.088
74/101 (73.3%) 24.77 3.15
25/35 (71.4%) 25.79 2.46
1.000 0.089
4/72 (5.6%)
13/64 (20.3%)
0.019
10/101 (9.9%)
7/35 (20%)
0.141
123 (18e2390)
114 (18e1434)
150 (43e2390)
0.017
111 (18e1510)
189 (72e2390)
<0.001
77 (16e1400)
63 (16e1084)
92 (19e1400)
0.004
62 (16e1160)
140 (39e1400)
<0.001
0.72 (0.17e10)
0.73 (0.19e1.9)
0.7 (0.17e10)
0.668
0.7 (0.17e1.9)
0.84 (0.32e10)
0.077
1.025 0.072
1.006 0.066
1.045 0.074
0.003
1.010 0.653
1.067 0.077
5935 1575
5934 1485
5935 1682
0.908
6132 1492
5365 1688
0.007
14.13 1.60
14.32 1.47
13.91 1.72
0.174
14.22 1.62
13.86 1.51
0.228
187 55.43
203 59.86
168 43.27
<0.001
198 55.22
154 41.60
<0.001
0.911 0.235 1.09 106 (2014e6.56 109)
0.922 0.239 1.08 106 (2014e6.56 109)
0.899 0.232 1.09 106 (2500e1.38 109)
0.90 0.230 6.03 105 (2014e6.56 109)
0.92 0.252 3.4 106 (2500e4.98 108)
5 2.936
3.65 2.386
6.52 2.766
<0.001
3.52 1.467
9.26 1.669
e
1.77 1.36 0.82 0.809
0.78 0.419 0.85 0.883
2.89 1.170 0.78 0.723
e
1.54 1.269 0.86 0.80
2.43 1.420 0.69 0.832
<0.001 0.165
Abbreviations: BMI, body mass index; DM, diabetes mellitus; INR, international normalized ratio.
0.437 0.180
0.948
<0.001
0.809 0.016
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3.2. Factors associated with significant liver fibrosis
Table 3 Factors associated with hepatic fibrosis and necro-inflammation by multivariate analysis.
By univariate analysis, factors associated with significant liver fibrosis were age > 50 years, BMI > 25 kg/m2, type 2 DM, elevated levels of serum ALT and AST, lower platelet count, and higher HBV DNA level (>10,000 IU/mL or >20,000 IU/mL) (Table 2). The presence or absence of hepatic steatosis did not correlate with liver fibrosis. Multivariate logistic regression analysis showed that BMI 25 kg/m2 (Odds ratio (OR) ¼ 3.758, p ¼ 0.001), AST > 40 U/L (OR ¼ 9.172, p ¼ 0.001), HBV DNA > 20,000 IU/mL (OR ¼ 4.596, p ¼ 0.012) and platelet count < 150 109/L (OR ¼ 2.839, p ¼ 0.026) were independent factors associated with significant liver fibrosis (Table 3).
Variable
p Value
Hepatic fibrosis (Ishak fibrosis stage 2) 0.001 BMI 25 kg/m2 AST > 40 U/L 0.001 HBV DNA > 20,000 IU/mL 0.012 0.026 Platelet < 150 109/L
Odds ratio
95% Confidence interval
3.758 9.172 4.596 2.839
1.665e8.483 2.388e35.226 1.392e15.172 1.131e7.126
Hepatic necro-inflammation (Ishak necro-inflammatory 0.005 7.359 BMI 23 kg/m2 ALT > 80 U/L 0.033 9.920 0.014 3.212 HBV DNA > 106 IU/mL 0.005 3.881 Platelet < 150 109/L
grade 7) 1.841e29.420 1.205e81.634 1.263e8.168 1.497e10.062
3.3. Factors associated with liver necro-inflammation 4. Discussion Univariate analysis revealed that age > 50 years, BMI 23 kg/ m2, elevated levels of serum ALT and AST, low WBC and platelet counts, longer pro-thrombin time, and higher HBV DNA level (>1,000,000 IU/mL) were associated with significant liver necroinflammation (Table 2). Type 2 DM and hepatic steatosis were not associated with necro-inflammation. Multivariate logistic regression analysis showed that BMI 23 kg/m2 (OR ¼ 7.359, p ¼ 0.005), ALT > 80 U/L (OR ¼ 9.920, p ¼ 0.033), HBV DNA > 1,000,000 IU/mL (OR ¼ 3.212, p ¼ 0.014), and platelet count < 150 109/L (OR ¼ 3.881, p ¼ 0.005) were independent factors associated with significant liver fibrosis (Table 3).
This study demonstrates that a significant proportion of HBeAgnegative CHB patients are either overweight or obese in Taiwan. Patients with high BMI are associated with significant liver histology. Overweight/obesity (BMI 23 kg/m2) is associated with significant liver necro-inflammation while obesity (BMI 25 kg/m2) is related to liver fibrosis. The association is independent of all well-known host and viral factors associated with disease progression in CHB, such as age, ALT, AST, or HBV DNA levels. In univariate analysis, age, obesity, type 2 DM, elevated AST and HBV DNA levels, and low platelet counts are associated with significant liver fibrosis. Similarly, age, overweight, elevated ALT, AST, prolonged INR, HBV DNA levels, and low WBC and platelet counts are factors associated with significant liver necro-inflammation. Several studies have shown that age, aminotransferase levels, low cell counts, and INR correlate with liver histology.20,23 It is also well known that HBV DNA has a significant impact on disease progression in CHB.24 Type 2 DM has also been reported to correlate with more advanced liver fibrosis.25 Although several factors are associated with liver histology by univariate analysis, only BMI, AST, HBV DNA and platelet counts remain as independent predictors of significant liver fibrosis by multivariate analysis. Similarly, we found that only BMI, ALT, HBV DNA and platelet counts were independent indicators associated with hepatic necro-inflammation. Note worthily, current AASLD treatment guideline recommends that ALT higher than two times upper limit of normal accompanied with HBV viral load higher than 20,000 IU/ml is clinical indication for treatment in HBeAgnegative CHB patients.17 In our finding, the two factors (ALT > 80
3.4. Risk stratification according to the BMI and HBV DNA levels Since BMI and HBV DNA were both independent factors associated with either liver fibrosis or necro-inflammation, the patients were stratified into four groups according to BMI and HBV DNA levels. The relative risk of significant liver histology among these groups was evaluated after adjusting for serum AST or ALT level and platelet counts (Table 4). Compared to patients with BMI 25 kg/ m2 and HBV DNA > 20,000 IU/mL, those with BMI < 25 kg/m2, HBV DNA 20,000 IU/mL, or both, was significantly associated with lower hepatic fibrosis (OR: 0.253, 0.191, and 0.083, respectively). Similarly, compared to patients with BMI 23 kg/m2 and HBV DNA > 106 IU/mL, patients with HBV DNA levels 106 IU/mL or BMI < 23 kg/m2 had significantly lower risk of necro-inflammation (OR: 0.320 and 0.124, respectively).
Table 2 Factors associated with hepatic fibrosis and necro-inflammation by univariate analysis. Ishak fibrosis stage 2
Variables
Cut-off value
Age (year) Sex BMI (kg/m2)
50 Male <23 <25 Negative
>50 Female 23 25 Positive
23/68 44/99 11/34 23/65 51/119
(33.8%) (44.4%) (32.4%) (35.4%) (42.9%)
41/68 20/37 53/102 41/71 13/17
(60.3%) (54.1%) (52%) (57.7%) (76.5%)
80 40 1.0 1.0 4000 13 150 1.1 20,000 106 Absence
>80 >40 >1.0 >1.0 >4000 >13 >150 >1.1 >20,000 >106 Presence
7/25 3/25 42/96 48/95 7/15 20/36 21/32 50/115 5/21 30/66 23/51
(28%) (12%) (43.8%) (50.5%) (46.7%) (55.6%) (65.6%) (43.5%) (23.8%) (45.5%) (45.1%)
57/111 61/111 20/37 16/41 57/121 44/100 43/104 14/21 59/115 34/70 41/85
(51.4%) (55%) (54.1%) (39%) (47.1%) (44%) (41.3%) (66.7%) (51.3%) (48.6%) (48.2%)
Type 2 DM Biochemical data ALT (U/L) AST (U/L) Total bilirubin (mg/dL) Creatinine (mg/dL) WBC (/cumm) Hb (g/dL) Platelet (109/L) Pro-thrombin time (INR) HBV DNA (IU/mL) Steatosis
p Value
Ishak necro-inflammatory grade 7
p Value
0.003 0.420 0.074 0.015 0.019
10/68 25/99 3/34 14/65 28/119
(14.7%) (25.3%) (8.8%) (21.5%) (23.5%)
25/68 10/37 32/102 21/71 7/17
(36.8%) (27%) (31.4%) (29.6%) (41.2%)
0.006 1.000 0.017 0.382 0.141
0.059 <0.001 0.382 0.296 1.000 0.319 0.028 0.085 0.037 0.848 0.859
1/25 2/25 20/96 24/95 8/15 11/36 16/32 24/115 3/21 11/66 17/51
(4%) (8%) (20.8%) (25.3%) (53.3%) (30.6%) (50%) (20.9%) (14.3%) (16.7%) (33.3%)
34/111 33/111 14/37 11/41 27/121 24/100 19/104 11/21 32/115 24/70 18/85
(30.6%) (29.7%) (37.8%) (26.8%) (22.3%) (24%) (18.3%) (52.4%) (27.8%) (34.3%) (21.2%)
0.012 0.046 0.073 1.000 0.023 0.583 0.001 0.006 0.301 0.031 0.172
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Table 4 Risk stratification of significant fibrosis and necro-inflammation by BMI and HBV DNA levels after adjusting for serum AST/ALT level and platelet counts. Case number
Odds ratio
95% Confidence interval
p Value
Ishak fibrosis stage 2 BMI < 25 kg/m2 DNA 20,000 IU/mL DNA > 20,000 IU/mL
1/6 (16.7%) 22/59 (37.3%)
0.083 0.253
0.008e0.836 0.108e0.594
0.035 0.002
BMI 25 kg/m2 DNA 20,000 IU/mL DNA > 20,000 IU/mL
4/15 (26.7%) 37/56 (66.1%)
0.191 1
0.049e0.751
0.018
Ishak necro-inflammatory grade 7 BMI < 23 kg/m2 DNA 106 IU/mL 0/12 (0%) 3/22 (13.6%) DNA > 106 IU/mL
e 0.124
e 0.028e0.558
e 0.007
BMI 23 kg/m2 DNA 106 IU/mL DNA > 106 IU/mL
0.320 1
0.116e0.878
0.027
11/54 (20.4%) 21/48 (43.8%)
U/L and HBV DNA > 20,000 IU/ml) were also associated with significant necro-inflammation and fibrosis, respectively.17 Hepatic steatosis is not an uncommon finding in HBeAgnegative CHB and it correlates well with BMI. However, hepatic steatosis is not associated with HBV DNA levels, hepatic fibrosis, or necro-inflammation. These findings are consistent with previous studies, which report that hepatic steatosis is associated with host metabolic factors but not viral factors in CHB.26 Therefore, in patients with hepatic steatosis, it is important to identify and control the co-existing metabolic disorders to prevent potentially harmful metabolic and cardio-vascular complications. Whether BMI is associated with liver histology in CHB has been debated before. Some studies show that BMI correlates with liver fibrosis in CHB27 but some studies do not.28 However, the population of previous studies are either younger or have a high percentage of HBeAg-positive patients and therefore, the stage of liver fibrosis is less prominent. The current study focuses on HBeAg-negative CHB patients, who tend to be older and with more advanced disease. Liver fibrosis is a dynamic process that is usually followed by hepatic necro-inflammation. In this cross-sectional observation, overweight contributes to hepatic necroinflammation and obesity leads to fibrosis. Both can aggravate liver histology in the presence of active viral replication (Fig. 2). The distinctive histological features of non-alcoholic steatohepatitis (NASH) include steatosis, hepato-cellular ballooning, lobular inflammation, which includes polymorphonuclear leukocytes, and perisinusoidal fibrosis in zone 3 of acinus.22 The histological features of chronic hepatitis B are characterized by mononuclear cells infiltration in the portal tract and ground-glass hepatocytes. In general, NASH and viral hepatitis have different histological features in necro-inflammation and fibrosis. Even though some features may overlap, we still could determine the predominant pathological features.22 The histological grading system for NASH all excluded patients with viral hepatitis, including the Brunt’s classification which we used for steatosis grading. Currently there is no standard grading or staging for NASH in viral hepatitis. Moreover, all patients in our study were chronic hepatitis B with high viral loads (HBV DNA 2000 IU/ml). On the other hand, not all patients had overweight/obesity or had presence of steatosis. Therefore, the scoring system for NASH could not be applied to all CHB patients in our study. For these reasons, we chose the Ishak scoring system for grading and staging and Brunt classification for steatosis grading.
Fig. 2. Interaction among hepatitis B virus, overweight, and obesity, and their impact on liver histology. Hepatitis B virus infection may predispose to progressive histologic liver damage with initial hepatic necro-inflammation, subsequent hepatic fibrosis, and cirrhosis. Alternatively, overweight and obesity are independently associated with hepatic necro-inflammation and fibrosis, respectively.
The underlying mechanism of histologic damage in relation to BMI can be an interaction of adipokines, including adiponectin, leptin, resistin, tumor necrosis factor and interleukin-6, which are polypeptides secreted in adipose tissue.29 Several studies demonstrate that adipokines may modulate hepatic steatosis, inflammation, and fibrosis, and increase the risk of HCC by promoting tumorigenesis.29 The interaction between adipokines and HBV is not fully understood although a recent report shows that adipokines and viral factors may contribute to liver injury independently.30 This study demonstrates that BMI and HBV DNA levels correlate with liver histology independently. It also demonstrates a trend towards increased risk of significant histologic damage in patients with either higher BMI or HBV DNA levels (Table 4). Such findings suggest a synergistic effect of BMI and HBV replication on disease progression in CHB. Therefore, it may be important to control body weight during anti-viral treatment in the management of CHB. This study has some limitations. This is a cross-sectional observation study. Therefore the long-term effect of overweight and obesity on liver histology and the potential role of weight reduction on improving serum ALT levels, liver histology, or response to antiviral therapy warrant further study. Some common metabolic parameters, such as fasting glucose, index of insulin resistance, and lipid profiles are lacking. Nonetheless, these factors have not been previously suggested as having an impact on the management of HBV infection and current guidelines do not recommend checking these profiles routinely during anti-viral therapy. In conclusion, BMI and HBV viral loads may have a synergistic effect on disease progression in CHB. Controlling body weight may have a potential benefit in the management of CHB. Statement of authorship The authors hereby certify that all authors concur with the submission and that the material submitted for publication has not been previously reported and are not under consideration for publication elsewhere. All authors have read and approved the manuscript. Contribution of the authors I-Cheng Lee: Analysis and interpretation of data; drafting of the manuscript. Yi-Hsiang Huang: Conception and design of the study; data collection and interpretation; revision and approval of the final version of the manuscript. Che-Chang Chan: Data collection and interpretation. Teh-Ia Huo: Data collection. Chi-Jen Chu: Data collection. Chiung-Ru Lai: Pathological examination.
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Pui-Ching Lee: Statistical analysis and interpretation of data. Chien-Wei Su: Data collection. Jaw-Ching Wu: Data collection. Han-Chieh Lin: Data collection. Shou-Dong Lee: Data collection. Conflict of interest The authors declared no conflict of interest.
Acknowledgements The study was supported by grants from the National Science Council (NSC96-2314-B-010-046) and Taipei Veterans General Hospital (VGH 98A-026, V97S5-002, V99C1-075, V100A-014, and V100C-104), Taipei, Taiwan.
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11. Wang YY, Lin SY, Sheu WH, Liu PH, Tung KC. Obesity and diabetic hyperglycemia were associated with serum alanine aminotransferase activity in patients with hepatitis B infection. Metabolism 2010;59:486e91. 12. Wong GL, Wong VW, Choi PC, Chan AW, Chim AM, Yiu KK, et al. Metabolic syndrome increases the risk of liver cirrhosis in chronic hepatitis B. Gut 2009;58:111e7. 13. Yu MW, Shih WL, Lin CL, Liu CJ, Jian JW, Tsai KS, et al. Body-mass index and progression of hepatitis B: a population-based cohort study in men. J Clin Oncol 2008;26:5576e82. 14. Liaw YF, Chu CM. Hepatitis B virus infection. Lancet 2009;373:582e92. 15. Huang YH, Wu JC, Chang TT, Sheen IJ, Huo TI, Lee PC, et al. Association of core promoter/precore mutations and viral load in e antigen-negative chronic hepatitis B patients. J Viral Hepat 2006;13:336e42. 16. Lee IC, Huang YH, Chan CC, Huo TI, Chu CJ, Lai CR, et al. Correlation between clinical indication for treatment and liver histology in HBeAg-negative chronic hepatitis B: a novel role of alpha-fetoprotein. Liver Int 2010;30:1161e8. 17. Lok AS, McMahon BJ. Chronic hepatitis B: update 2009. Hepatology 2009;50:661e2. 18. Appropriate body-mass index for Asian populations and its implications for policy and intervention strategies. Lancet 2004;363:157e63. 19. Ishak K, Baptista A, Bianchi L, Callea F, De Groote J, Gudat F, et al. Histological grading and staging of chronic hepatitis. J Hepatol 1995;22:696e9. 20. Lee IC, Chan CC, Huang YH, Huo TI, Chu CJ, Lai CR, et al. Comparative analysis of noninvasive models to predict early liver fibrosis in hepatitis B e antigennegative chronic hepatitis B. J Clin Gastroenterol 2011;45(3):278e85. 21. Papatheodoridis GV, Manesis EK, Manolakopoulos S, Elefsiniotis IS, Goulis J, Giannousis J, et al. Is there a meaningful serum hepatitis B virus DNA cutoff level for therapeutic decisions in hepatitis B e antigen-negative chronic hepatitis B virus infection? Hepatology 2008;48:1451e9. 22. Brunt EM, Janney CG, Di Bisceglie AM, Neuschwander-Tetri BA, Bacon BR. Nonalcoholic steatohepatitis: a proposal for grading and staging the histological lesions. Am J Gastroenterol 1999;94:2467e74. 23. Lackner C, Struber G, Liegl B, Leibl S, Ofner P, Bankuti C, et al. Comparison and validation of simple noninvasive tests for prediction of fibrosis in chronic hepatitis C. Hepatology 2005;41:1376e82. 24. Iloeje UH, Yang HI, Su J, Jen CL, You SL, Chen CJ. Predicting cirrhosis risk based on the level of circulating hepatitis B viral load. Gastroenterology 2006;130:678e86. 25. Papatheodoridis GV, Chrysanthos N, Savvas S, Sevastianos V, Kafiri G, Petraki K, et al. Diabetes mellitus in chronic hepatitis B and C: prevalence and potential association with the extent of liver fibrosis. J Viral Hepat 2006;13:303e10. 26. Yun JW, Cho YK, Park JH, Kim HJ, Park DI, Sohn CI, et al. Hepatic steatosis and fibrosis in young men with treatment-naive chronic hepatitis B. Liver Int 2009;29:878e83. 27. Hui AY, Chan HL, Wong VW, Liew CT, Chim AM, Chan FK, et al. Identification of chronic hepatitis B patients without significant liver fibrosis by a simple noninvasive predictive model. Am J Gastroenterol 2005;100:616e23. 28. Park SH, Kim DJ, Lee HY. Insulin resistance is not associated with histologic severity in nondiabetic, noncirrhotic patients with chronic hepatitis B virus infection. Am J Gastroenterol 2009;104:1135e9. 29. Marra F, Bertolani C. Adipokines in liver diseases. Hepatology 2009;50:957e69. 30. Wong VW, Wong GL, Yu J, Choi PC, Chan AW, Chan HY, et al. Interaction of adipokines and hepatitis B virus on histological liver injury in the Chinese. Am J Gastroenterol 2010;105:132e8.
Contents lists available at ScienceDirect
Clinical Nutrition journal homepage: http://www.elsevier.com/locate/clnu
Original article
Impact of body mass index and viral load on liver histology in hepatitis B e antigen-negative chronic hepatitis B I-Cheng Lee a, b, Yi-Hsiang Huang a, b, *, Che-Chang Chan a, b, Teh-Ia Huo b, c, Chi-Jen Chu b, Chiung-Ru Lai d, Pui-Ching Lee b, Chien-Wei Su a, b, Jaw-Ching Wu a, e, Han-Chieh Lin b, Shou-Dong Lee b a
Institute of Clinical Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan Division of Gastroenterology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan Institute of Pharmacology, National Yang-Ming University School of Medicine, Taipei, Taiwan d Department of Pathology, Taipei Veterans General Hospital, Taipei, Taiwan e Department of Medical Research and Education, Taipei Veterans General Hospital, Taipei, Taiwan b c
a r t i c l e i n f o
s u m m a r y
Article history: Received 26 October 2010 Accepted 2 May 2011
Background & aims: The impact of overweight and obesity on chronic hepatitis B (CHB) is unclear. This study was to examine the relationship among body mass index, viral load and liver histology in HBeAgnegative CHB. Methods: The study retrospectively investigated 136 HBeAg-negative chronic hepatitis B patients who had undergone liver biopsies in Taiwan. Factors associated with significant liver histology were analyzed. Definitions of overweight and obesity for the Asian population were body mass index 23 kg/m2 and 25 kg/m2, respectively. Results: The prevalence of overweight, obesity, and type 2 diabetes mellitus in the 136 patients were 22.8%, 52.2%, and 12.5%, respectively. Multivariate analysis identified obesity, AST > 40 U/L, HBV DNA > 20,000 IU/mL and platelet count < 150 109/L as independent factors associated with significant liver fibrosis. Similarly, overweight/obesity, ALT > 80 U/L, HBV DNA > 1,000,000 IU/mL, and platelet count < 150 109/L were independent predictors of significant hepatic necro-inflammation. By stratification, high BMI and high viral load patients had more advanced stage and grade of liver histology. Conclusions: Body mass index and HBV viral loads may have synergistic effect on disease progression in HBeAg-negative CHB. Both controlling body weight and anti-viral therapy are important in the management of CHB. Ó 2011 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.
Keywords: Body mass index Chronic hepatitis B Hepatitis B e antigen-negative Hepatitis B virus Liver histology Obesity
1. Introduction Obesity remains a growing public health concern and its prevalence is increasing at an alarming rate worldwide.1 Multiple studies have documented the adverse health consequences of overweight and obesity, including diabetes mellitus (DM), coronary heart disease, certain forms of cancer, and increased mortality from
Abbreviations: BMI, body mass index; HBeAg, hepatitis B e antigen; CHB, chronic hepatitis B; OR, odds ratio; DM, diabetes mellitus; ALT, alanine aminotransferase; NAFLD, non-alcoholic fatty liver disease; HCC, hepato-cellular carcinoma; CHC, chronic hepatitis C; HBV, hepatitis B virus; HIV, human immunodeficiency virus; HBsAg, hepatitis B surface antigen; AST, aspartate aminotransferase; INR, international normalized ratio. * Corresponding author. Division of Gastroenterology, Department of Medicine, Taipei Veterans General Hospital, 201 Shih-Pai Road, Sec. 2, Taipei 112, Taiwan. Tel.: þ886 2 28712121x3055; fax: þ886 2 28739318. E-mail address: [email protected] (Y.-H. Huang).
all cause.2 The adverse impact of obesity on the liver contributes to the development of hepatic steatosis, non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steato-hepatitis.3 Obesity also reportedly correlates with increased risk of cirrhosis-related death or hospitalization,4 as well as the development of hepato-cellular carcinoma (HCC).5 It is well known that obesity and metabolic factors play important roles in the progression and response to anti-viral therapy in chronic hepatitis C (CHC).6 Weight loss alone in CHC patients is associated with a reduction in steatosis and improvement in liver enzymes and liver fibrosis.7 Moreover, control of metabolic factors and attempts to lose weight are suggested for such patients because weight reduction and improvement in insulin resistance may improve the response to anti-hepatitis C virus (HCV) therapy.8 In Taiwan, hepatitis B virus (HBV) infection is the most important etiology of chronic liver disease.9 Several factors are associated
0261-5614/$ e see front matter Ó 2011 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved. doi:10.1016/j.clnu.2011.05.001
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with CHB disease progression, including age, sex, immune status, viral load, HBV genotype, concurrent HCV or human immunodeficiency virus (HIV) infection, and several environmental exposures.10 In CHB patients, obesity is associated with elevated ALT activity.11 Those with metabolic syndrome carry a higher risk of liver stiffness.12 Obesity is also independently associated with HCC development in HBV carriers.13 In general, after hepatitis B e antigen (HBeAg) sero-conversion, 10e30% of patients may develop HBeAg-negative CHB, in whom HBV DNA replicates and the disease progresses.14 HBeAg-negative CHB represents a unique phase in the natural history of chronic HBV infection.15 These patients tend to be older, have more advanced liver disease, and have more evidence of long-term adverse effects of obesity. Treatment remains a clinical challenge and it may be beneficial to identify a correctable metabolic factor with impact on the progression of CHB. The relationship between body mass index (BMI) and liver histology in HBeAg-negative CHB has not been well studied. This study aimed to evaluate the association of BMI with hepatic fibrosis and necro-inflammation in HBeAg-negative CHB. 2. Materials and methods
the Study of Liver Disease (AASLD) treatment guidelines.17 None received anti-viral treatment (nucleoside/nucleotide analogues or interferon) before liver biopsy. The exclusion criteria were (1) HCV, hepatitis D virus, or HIV coinfection, (2) anti-nuclear antibody titer 1:160, positive test for anti-smooth muscle antibody or anti-mitochondrial antibody, (3) use of hepatotoxic drug or Chinese herb, (4) alcoholic liver disease, and (5) radiologic evidence of HCC (i.e., abdominal sonogram, computed tomography scan, or magnetic resonance imaging scans). Of the 330 CHB patients, 233 were HBeAg-negative. Twenty-five patients were excluded, including 8 with HCV co-infection, 8 with history of drug or herb use, 8 with HCC, and 1 who tested positive for ANA. Fifty-six patients did not have HBV DNA data within two weeks of liver biopsy and sixteen had HBV DNA level < 2000 IU/mL. The remaining 136 patients were enrolled (Fig. 1). Their clinical features, biochemical data, HBV viral loads within 2 week of liver biopsy, and medical history of type 2 DM were recorded. According to the World Health Organization guidelines for adult Asian population, BMI was categorized as normal (BMI < 23 kg/m2), overweight (BMI 23 kg/m2 but <25 kg/m2), or obese (BMI 25 kg/ m2).18 The institutional review board of Taipei Veterans General Hospital, Taipei, Taiwan approved the study.
2.1. Patients
2.2. Liver histology evaluation
Before November 2009, regulations of the Bureau of National Health Insurance, Taiwan, required that liver biopsy be performed to determine the necessity of anti-viral therapy for patients with HBeAg-negative CHB. From July 2006 to October 2009, 330 consecutive, treatment-naïve CHB patients who underwent liver biopsy at the Taipei Veterans General Hospital were screened.16 Among them, 233 were negative for HBeAg. The inclusion criteria were as follows: positive test for serum hepatitis B surface antigen (HBsAg) and negative test for HBeAg for at least six months, elevated serum ALT level (40 U/L, 1 upper limit of the normal range) recorded at least 2 distinct instances at an interval of one month, and HBV DNA level > 2000 IU/mL (tested using Cobas Amplicor HBV monitor, which has a detection limit of 12 IU/mL). Anti-viral treatment for all enrolled patients followed the American Association for
Liver tissue was obtained via ultrasound-guided percutaneous biopsy using a Tru-Cut needle (18G, Cardinal Health, McGaw Park, IL). All of the specimens were at least 1.5 cm in length. The average number of portal tracts in the biopsy specimens was 10.3 (range 7e14). Histological grading of the necro-inflammation and staging of the liver fibrosis were done according to the Ishak scoring system.19 Necro-inflammation was graded from 0 to 18, while fibrosis was staged from 0 to 6. According to the definition by Papatheodoridis et al., significant necro-inflammation was defined as grade 7 and significant fibrosis as stage 2 as per Ishak’s classification system.20,21 Hepatic steatosis was graded according to the Brunt classification: 0 (no hepatocytes involved with macro-vesicular steatosis), 1 (0e33% involved), 2 (33e66% involved) and 3 (>66% involved).22 A
Fig. 1. Profile of the study patients and their categorization based on body mass index and liver histology.
I.-C. Lee et al. / Clinical Nutrition 30 (2011) 647e652
single pathologist blinded to clinical information of the patients performed the pathology examinations of all liver biopsy specimens. 2.3. Liver biochemistry and viral serology tests Serum biochemical studies were performed using a systemic multi-auto-analyzer (Technicon SMAC, Technicon Instruments Corp., Tarrytown, NY). Serum samples were tested for the presence of HBsAg, HBeAg, and anti-HBeAg antibody using radioimmunoassay (Abbott Laboratories, North Chicago, IL), while a Cobas Amplicor HBV monitor determined the HBV DNA. 2.4. Statistical analysis All statistical analyses were performed using the Statistical Package for Social Sciences (SPSS 17.0 for Windows, SPSS Inc., Chicago, IL). Pearson chi-square analysis or Fisher exact test was used to compare categorical variables, while the Student t test or one-way ANOVA was used for group comparisons of parametric quantitative data. The ManneWhitney U or KruskaleWallis test was used for similar comparisons of non-parametric data. Variables with p < 0.1 were analyzed by multivariate logistic regression analysis to identify independent variables for predicting liver histology. The best cut-off value of each variable was determined by the receiver-operating characteristic curve using MedCalc (version 4.20, MedCalc Software, Mariakerke, Belgium). A twotailed p < 0.05 was considered statistically significant.
649
3. Results 3.1. Patient characteristics The baseline characteristics of the 136 patients and those with and without significant liver fibrosis (Ishak stage 2) or significant liver necro-inflammation (Ishak grade 7) were summarized in Table 1. Their mean age was 50.9 years and mean BMI was 25.3 kg/m2. Ninety-nine (72.8%) were males. Thirty-one (22.8%) patients were overweight, 71 (52.2%) had obesity, and 17 (12.5%) had type 2 DM. There was hepatic steatosis in 85 (62.5%) patients, including 67 (49.3%) grade 1, 10 (7.4%) grade 2, and eight (5.9%) grade 3. The histological features in all CHB patients with steatosis were still viral hepatitis predominant. Sixty-four (47.1%) had significant liver fibrosis, including six patients (4.4%) with cirrhosis, and 35 (25.7%) had significant necro-inflammation (Fig. 1). Patients with significant liver fibrosis were older, had higher prevalence of type 2 DM, higher ALT and aspartate aminotransferase (AST) levels, longer pro-thrombin times measured by international normalized ratio (INR), lower platelet counts, and greater Ishak necro-inflammatory grade. Patients with significant necroinflammation were older, had higher ALT and AST levels, longer pro-thrombin times, lower WBC and platelet counts, higher HBV DNA levels, and greater Ishak fibrosis score. Patients who presented with hepatic steatosis had significantly higher BMI (25.9 vs. 23.6 kg/m2, p < 0.001). However, the presence or absence of hepatic steatosis was not correlated with HBV DNA levels (9.6 107 vs. 4.9 107 IU/mL, p ¼ 0.205).
Table 1 Baseline characteristics of HBeAg-negative chronic hepatitis B patients (n ¼ 136). Characteristic
Demographics Age (years) Male gender BMI (kg/m2) Type 2 DM Biochemical markers ALT (U/L) AST (U/L) Total bilirubin (mg/dL) Pro-thrombin time (INR) WBC (/cumm) Hemoglobin (g/dL) Platelet (109/L) Creatinine (mg/dL) HBV DNA (IU/mL) Histology Ishak necro-inflammatory grade Ishak fibrosis score Steatosis grade
All (n ¼ 136)
Ishak fibrosis stage
p Value
<2 (n ¼ 72)
2 (n ¼ 64)
50.9 12.4
48.1 11.6
54.0 12.6
99 (72.8%) 25.03 3.01
55/72 (76.4%) 24.75 2.92
17 (12.5%)
Ishak necro-inflammatory grading
p Value
<7 (n ¼ 101)
7 (n ¼ 35)
0.003
48.8 12.2
56.8 11.1
0.001
44/64 (68.8%) 25.35 3.11
0.420 0.088
74/101 (73.3%) 24.77 3.15
25/35 (71.4%) 25.79 2.46
1.000 0.089
4/72 (5.6%)
13/64 (20.3%)
0.019
10/101 (9.9%)
7/35 (20%)
0.141
123 (18e2390)
114 (18e1434)
150 (43e2390)
0.017
111 (18e1510)
189 (72e2390)
<0.001
77 (16e1400)
63 (16e1084)
92 (19e1400)
0.004
62 (16e1160)
140 (39e1400)
<0.001
0.72 (0.17e10)
0.73 (0.19e1.9)
0.7 (0.17e10)
0.668
0.7 (0.17e1.9)
0.84 (0.32e10)
0.077
1.025 0.072
1.006 0.066
1.045 0.074
0.003
1.010 0.653
1.067 0.077
5935 1575
5934 1485
5935 1682
0.908
6132 1492
5365 1688
0.007
14.13 1.60
14.32 1.47
13.91 1.72
0.174
14.22 1.62
13.86 1.51
0.228
187 55.43
203 59.86
168 43.27
<0.001
198 55.22
154 41.60
<0.001
0.911 0.235 1.09 106 (2014e6.56 109)
0.922 0.239 1.08 106 (2014e6.56 109)
0.899 0.232 1.09 106 (2500e1.38 109)
0.90 0.230 6.03 105 (2014e6.56 109)
0.92 0.252 3.4 106 (2500e4.98 108)
5 2.936
3.65 2.386
6.52 2.766
<0.001
3.52 1.467
9.26 1.669
e
1.77 1.36 0.82 0.809
0.78 0.419 0.85 0.883
2.89 1.170 0.78 0.723
e
1.54 1.269 0.86 0.80
2.43 1.420 0.69 0.832
<0.001 0.165
Abbreviations: BMI, body mass index; DM, diabetes mellitus; INR, international normalized ratio.
0.437 0.180
0.948
<0.001
0.809 0.016
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3.2. Factors associated with significant liver fibrosis
Table 3 Factors associated with hepatic fibrosis and necro-inflammation by multivariate analysis.
By univariate analysis, factors associated with significant liver fibrosis were age > 50 years, BMI > 25 kg/m2, type 2 DM, elevated levels of serum ALT and AST, lower platelet count, and higher HBV DNA level (>10,000 IU/mL or >20,000 IU/mL) (Table 2). The presence or absence of hepatic steatosis did not correlate with liver fibrosis. Multivariate logistic regression analysis showed that BMI 25 kg/m2 (Odds ratio (OR) ¼ 3.758, p ¼ 0.001), AST > 40 U/L (OR ¼ 9.172, p ¼ 0.001), HBV DNA > 20,000 IU/mL (OR ¼ 4.596, p ¼ 0.012) and platelet count < 150 109/L (OR ¼ 2.839, p ¼ 0.026) were independent factors associated with significant liver fibrosis (Table 3).
Variable
p Value
Hepatic fibrosis (Ishak fibrosis stage 2) 0.001 BMI 25 kg/m2 AST > 40 U/L 0.001 HBV DNA > 20,000 IU/mL 0.012 0.026 Platelet < 150 109/L
Odds ratio
95% Confidence interval
3.758 9.172 4.596 2.839
1.665e8.483 2.388e35.226 1.392e15.172 1.131e7.126
Hepatic necro-inflammation (Ishak necro-inflammatory 0.005 7.359 BMI 23 kg/m2 ALT > 80 U/L 0.033 9.920 0.014 3.212 HBV DNA > 106 IU/mL 0.005 3.881 Platelet < 150 109/L
grade 7) 1.841e29.420 1.205e81.634 1.263e8.168 1.497e10.062
3.3. Factors associated with liver necro-inflammation 4. Discussion Univariate analysis revealed that age > 50 years, BMI 23 kg/ m2, elevated levels of serum ALT and AST, low WBC and platelet counts, longer pro-thrombin time, and higher HBV DNA level (>1,000,000 IU/mL) were associated with significant liver necroinflammation (Table 2). Type 2 DM and hepatic steatosis were not associated with necro-inflammation. Multivariate logistic regression analysis showed that BMI 23 kg/m2 (OR ¼ 7.359, p ¼ 0.005), ALT > 80 U/L (OR ¼ 9.920, p ¼ 0.033), HBV DNA > 1,000,000 IU/mL (OR ¼ 3.212, p ¼ 0.014), and platelet count < 150 109/L (OR ¼ 3.881, p ¼ 0.005) were independent factors associated with significant liver fibrosis (Table 3).
This study demonstrates that a significant proportion of HBeAgnegative CHB patients are either overweight or obese in Taiwan. Patients with high BMI are associated with significant liver histology. Overweight/obesity (BMI 23 kg/m2) is associated with significant liver necro-inflammation while obesity (BMI 25 kg/m2) is related to liver fibrosis. The association is independent of all well-known host and viral factors associated with disease progression in CHB, such as age, ALT, AST, or HBV DNA levels. In univariate analysis, age, obesity, type 2 DM, elevated AST and HBV DNA levels, and low platelet counts are associated with significant liver fibrosis. Similarly, age, overweight, elevated ALT, AST, prolonged INR, HBV DNA levels, and low WBC and platelet counts are factors associated with significant liver necro-inflammation. Several studies have shown that age, aminotransferase levels, low cell counts, and INR correlate with liver histology.20,23 It is also well known that HBV DNA has a significant impact on disease progression in CHB.24 Type 2 DM has also been reported to correlate with more advanced liver fibrosis.25 Although several factors are associated with liver histology by univariate analysis, only BMI, AST, HBV DNA and platelet counts remain as independent predictors of significant liver fibrosis by multivariate analysis. Similarly, we found that only BMI, ALT, HBV DNA and platelet counts were independent indicators associated with hepatic necro-inflammation. Note worthily, current AASLD treatment guideline recommends that ALT higher than two times upper limit of normal accompanied with HBV viral load higher than 20,000 IU/ml is clinical indication for treatment in HBeAgnegative CHB patients.17 In our finding, the two factors (ALT > 80
3.4. Risk stratification according to the BMI and HBV DNA levels Since BMI and HBV DNA were both independent factors associated with either liver fibrosis or necro-inflammation, the patients were stratified into four groups according to BMI and HBV DNA levels. The relative risk of significant liver histology among these groups was evaluated after adjusting for serum AST or ALT level and platelet counts (Table 4). Compared to patients with BMI 25 kg/ m2 and HBV DNA > 20,000 IU/mL, those with BMI < 25 kg/m2, HBV DNA 20,000 IU/mL, or both, was significantly associated with lower hepatic fibrosis (OR: 0.253, 0.191, and 0.083, respectively). Similarly, compared to patients with BMI 23 kg/m2 and HBV DNA > 106 IU/mL, patients with HBV DNA levels 106 IU/mL or BMI < 23 kg/m2 had significantly lower risk of necro-inflammation (OR: 0.320 and 0.124, respectively).
Table 2 Factors associated with hepatic fibrosis and necro-inflammation by univariate analysis. Ishak fibrosis stage 2
Variables
Cut-off value
Age (year) Sex BMI (kg/m2)
50 Male <23 <25 Negative
>50 Female 23 25 Positive
23/68 44/99 11/34 23/65 51/119
(33.8%) (44.4%) (32.4%) (35.4%) (42.9%)
41/68 20/37 53/102 41/71 13/17
(60.3%) (54.1%) (52%) (57.7%) (76.5%)
80 40 1.0 1.0 4000 13 150 1.1 20,000 106 Absence
>80 >40 >1.0 >1.0 >4000 >13 >150 >1.1 >20,000 >106 Presence
7/25 3/25 42/96 48/95 7/15 20/36 21/32 50/115 5/21 30/66 23/51
(28%) (12%) (43.8%) (50.5%) (46.7%) (55.6%) (65.6%) (43.5%) (23.8%) (45.5%) (45.1%)
57/111 61/111 20/37 16/41 57/121 44/100 43/104 14/21 59/115 34/70 41/85
(51.4%) (55%) (54.1%) (39%) (47.1%) (44%) (41.3%) (66.7%) (51.3%) (48.6%) (48.2%)
Type 2 DM Biochemical data ALT (U/L) AST (U/L) Total bilirubin (mg/dL) Creatinine (mg/dL) WBC (/cumm) Hb (g/dL) Platelet (109/L) Pro-thrombin time (INR) HBV DNA (IU/mL) Steatosis
p Value
Ishak necro-inflammatory grade 7
p Value
0.003 0.420 0.074 0.015 0.019
10/68 25/99 3/34 14/65 28/119
(14.7%) (25.3%) (8.8%) (21.5%) (23.5%)
25/68 10/37 32/102 21/71 7/17
(36.8%) (27%) (31.4%) (29.6%) (41.2%)
0.006 1.000 0.017 0.382 0.141
0.059 <0.001 0.382 0.296 1.000 0.319 0.028 0.085 0.037 0.848 0.859
1/25 2/25 20/96 24/95 8/15 11/36 16/32 24/115 3/21 11/66 17/51
(4%) (8%) (20.8%) (25.3%) (53.3%) (30.6%) (50%) (20.9%) (14.3%) (16.7%) (33.3%)
34/111 33/111 14/37 11/41 27/121 24/100 19/104 11/21 32/115 24/70 18/85
(30.6%) (29.7%) (37.8%) (26.8%) (22.3%) (24%) (18.3%) (52.4%) (27.8%) (34.3%) (21.2%)
0.012 0.046 0.073 1.000 0.023 0.583 0.001 0.006 0.301 0.031 0.172
I.-C. Lee et al. / Clinical Nutrition 30 (2011) 647e652
651
Table 4 Risk stratification of significant fibrosis and necro-inflammation by BMI and HBV DNA levels after adjusting for serum AST/ALT level and platelet counts. Case number
Odds ratio
95% Confidence interval
p Value
Ishak fibrosis stage 2 BMI < 25 kg/m2 DNA 20,000 IU/mL DNA > 20,000 IU/mL
1/6 (16.7%) 22/59 (37.3%)
0.083 0.253
0.008e0.836 0.108e0.594
0.035 0.002
BMI 25 kg/m2 DNA 20,000 IU/mL DNA > 20,000 IU/mL
4/15 (26.7%) 37/56 (66.1%)
0.191 1
0.049e0.751
0.018
Ishak necro-inflammatory grade 7 BMI < 23 kg/m2 DNA 106 IU/mL 0/12 (0%) 3/22 (13.6%) DNA > 106 IU/mL
e 0.124
e 0.028e0.558
e 0.007
BMI 23 kg/m2 DNA 106 IU/mL DNA > 106 IU/mL
0.320 1
0.116e0.878
0.027
11/54 (20.4%) 21/48 (43.8%)
U/L and HBV DNA > 20,000 IU/ml) were also associated with significant necro-inflammation and fibrosis, respectively.17 Hepatic steatosis is not an uncommon finding in HBeAgnegative CHB and it correlates well with BMI. However, hepatic steatosis is not associated with HBV DNA levels, hepatic fibrosis, or necro-inflammation. These findings are consistent with previous studies, which report that hepatic steatosis is associated with host metabolic factors but not viral factors in CHB.26 Therefore, in patients with hepatic steatosis, it is important to identify and control the co-existing metabolic disorders to prevent potentially harmful metabolic and cardio-vascular complications. Whether BMI is associated with liver histology in CHB has been debated before. Some studies show that BMI correlates with liver fibrosis in CHB27 but some studies do not.28 However, the population of previous studies are either younger or have a high percentage of HBeAg-positive patients and therefore, the stage of liver fibrosis is less prominent. The current study focuses on HBeAg-negative CHB patients, who tend to be older and with more advanced disease. Liver fibrosis is a dynamic process that is usually followed by hepatic necro-inflammation. In this cross-sectional observation, overweight contributes to hepatic necroinflammation and obesity leads to fibrosis. Both can aggravate liver histology in the presence of active viral replication (Fig. 2). The distinctive histological features of non-alcoholic steatohepatitis (NASH) include steatosis, hepato-cellular ballooning, lobular inflammation, which includes polymorphonuclear leukocytes, and perisinusoidal fibrosis in zone 3 of acinus.22 The histological features of chronic hepatitis B are characterized by mononuclear cells infiltration in the portal tract and ground-glass hepatocytes. In general, NASH and viral hepatitis have different histological features in necro-inflammation and fibrosis. Even though some features may overlap, we still could determine the predominant pathological features.22 The histological grading system for NASH all excluded patients with viral hepatitis, including the Brunt’s classification which we used for steatosis grading. Currently there is no standard grading or staging for NASH in viral hepatitis. Moreover, all patients in our study were chronic hepatitis B with high viral loads (HBV DNA 2000 IU/ml). On the other hand, not all patients had overweight/obesity or had presence of steatosis. Therefore, the scoring system for NASH could not be applied to all CHB patients in our study. For these reasons, we chose the Ishak scoring system for grading and staging and Brunt classification for steatosis grading.
Fig. 2. Interaction among hepatitis B virus, overweight, and obesity, and their impact on liver histology. Hepatitis B virus infection may predispose to progressive histologic liver damage with initial hepatic necro-inflammation, subsequent hepatic fibrosis, and cirrhosis. Alternatively, overweight and obesity are independently associated with hepatic necro-inflammation and fibrosis, respectively.
The underlying mechanism of histologic damage in relation to BMI can be an interaction of adipokines, including adiponectin, leptin, resistin, tumor necrosis factor and interleukin-6, which are polypeptides secreted in adipose tissue.29 Several studies demonstrate that adipokines may modulate hepatic steatosis, inflammation, and fibrosis, and increase the risk of HCC by promoting tumorigenesis.29 The interaction between adipokines and HBV is not fully understood although a recent report shows that adipokines and viral factors may contribute to liver injury independently.30 This study demonstrates that BMI and HBV DNA levels correlate with liver histology independently. It also demonstrates a trend towards increased risk of significant histologic damage in patients with either higher BMI or HBV DNA levels (Table 4). Such findings suggest a synergistic effect of BMI and HBV replication on disease progression in CHB. Therefore, it may be important to control body weight during anti-viral treatment in the management of CHB. This study has some limitations. This is a cross-sectional observation study. Therefore the long-term effect of overweight and obesity on liver histology and the potential role of weight reduction on improving serum ALT levels, liver histology, or response to antiviral therapy warrant further study. Some common metabolic parameters, such as fasting glucose, index of insulin resistance, and lipid profiles are lacking. Nonetheless, these factors have not been previously suggested as having an impact on the management of HBV infection and current guidelines do not recommend checking these profiles routinely during anti-viral therapy. In conclusion, BMI and HBV viral loads may have a synergistic effect on disease progression in CHB. Controlling body weight may have a potential benefit in the management of CHB. Statement of authorship The authors hereby certify that all authors concur with the submission and that the material submitted for publication has not been previously reported and are not under consideration for publication elsewhere. All authors have read and approved the manuscript. Contribution of the authors I-Cheng Lee: Analysis and interpretation of data; drafting of the manuscript. Yi-Hsiang Huang: Conception and design of the study; data collection and interpretation; revision and approval of the final version of the manuscript. Che-Chang Chan: Data collection and interpretation. Teh-Ia Huo: Data collection. Chi-Jen Chu: Data collection. Chiung-Ru Lai: Pathological examination.
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Pui-Ching Lee: Statistical analysis and interpretation of data. Chien-Wei Su: Data collection. Jaw-Ching Wu: Data collection. Han-Chieh Lin: Data collection. Shou-Dong Lee: Data collection. Conflict of interest The authors declared no conflict of interest.
Acknowledgements The study was supported by grants from the National Science Council (NSC96-2314-B-010-046) and Taipei Veterans General Hospital (VGH 98A-026, V97S5-002, V99C1-075, V100A-014, and V100C-104), Taipei, Taiwan.
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