Introduction 

Hepatitis B virus (HBV) is a hepatotropic, double-stranded DNA virus from the hepadnavirus family and contains multiple antigens (HBsAg, HBcAg, HBeAg). Damage to liver cells in HBV-related hepatitis is attributed to immune mechanisms. The main source of infection is contamination via body fluids / blood from previously infected or acutely ill individuals [1]. 

Despite the new diagnostic and preventive methods used today, hepatitis B virus (HBV) infection is still an important health problem worldwide with its potential adverse effects such as chronic hepatitis, cirrhosis and hepatocellular carcinoma and high morbidity and mortality rates. Approximately two billion people worldwide is recorded as infected with HBV, and 400 million of them results in chronic infection [1, 2]. The course of chronic hepatitis B is still not accurately perceived due to its variable and complex nature. Clinical data have major importance to understand the factors influencing progression of the disease and provide guidance for treatment planning [3]. 

Metabolic syndrome is a proinflammatory, prothrombotic condition, associated with the development of cardiovascular diseases and Type 2 diabetes which is caused by the combination of risk factors that are thought to share a common etiopathogenesis, such as impaired glucose and insulin metabolism, obesity, dyslipidemia, atherosclerosis, and hypertension [4]. As it has a very important role in cardiovascular mortality and morbidity in developed countries; metabolic syndrome has become increasingly important in the last century [5]. 

Metabolic syndrome is accompanied by coagulation/fibrinolytic system abnormalities that lead to a procoagulant state. In this stuation, the levels of procoagulants and anticoagulants in the plasma changes. The effect of metabolic syndrome on hepatic fibrosis in chronic hepatitis B patients has not yet been clearly defined [6, 7]. Several adipokines, such as leptin and adiponectin, secreted in these patients suggested to play a causative role in liver fibrosis [8]. An association between liver fibrosis and metabolic syndrome in nonalcoholic fatty liver disease (NAFLD) is also reported in various studies [9, 10]. Adjunctly the components of metabolic syndrome are found to be independent risk factors of liver fibrosis [11-13]. 

Taking the increasing prevalence of sedentary lifestyle and unhealthy eating habits into consideration which leads to an increase in the prevalence of metabolic syndrome. we ained to investigate the prevalence of metabolic syndrome and its effect on liver fibrosis in patients with chronic hepatitis B. 

Patients and Methods 

The study included male and female patients over the age of 18 who were followed up in the inpatient clinic of the Internal Medicine Gastroenterology Department of Fırat University Hospital and who applied to the gastroenterology clinic between February and June 2011 and were followed up with the diagnosis of chronic hepatitis B. All patients were informed about the study and their verbal consents and the approval of the e were obtained. The study was approved by the Scientific Research Ethics Committee of Fırat University Faculty of Medicine (protocol code:2011/05-05). All procedures were performed in terms of the ethical standards of the institutional research committee in alliance with the 1964 Helsinki Declaration and its later amendments.   

Exclusion Criteria: Patients co-infected with HIV, anti-HDV positive, patients with other accompanying liver pathologies such as hepatitis C infection, metabolic or genetic liver diseases, pregnant women, patients with alcohol consumption of more than 20 g/day and those with a history of exposure to hepatotoxic drugs.  

The liver biopsy results and laboratory findings and of the patients such as HBsAg titer, Anti-HBc IgG/M titer, HBV-DNA titer, HBeAg, Anti-HbeAg, anti-Delta IgG (Total) antibody, Anti-HCV, complete blood count, prothrombin time (PTZ-INR), serum glucose, cholesterol, HDL and LDL-cholesterol, triglyceride and liver enzymes (AST, ALT), alkaline phosphatase, gamma-glutamyl transferase and insulin levels were retrospectively reviewed from patient files or hospital archives.  

Demographically; age, gender, waistline, blood pressure arterial factors were examined. Blood pressure of the patients was measured in an upright sitting position, from the right arm and after at least 10 minutes of rest, using a mercury manometer based on Korotkoff phase I and phase V sounds. Systolic and diastolic pressure of 130 mmHg and 85 mmHg and above respectively were recorded as hypertension. JNC VII criteria were used for the diagnosis of hypertension. Waistline was measured with a tape measure from the narrowest point between the lower rib margin and the anterior superior iliac spine after deep expiration. 

Body mass index (BMI) was calculated by using the Quetlet index (weight/height²: kg/m²). HOMA-IR method was used for assessment of insulin resistance (HOMA-IR = fasting plasma insulin (µU/ml) x fasting plasma glucose (mmol/L) / 22.5). Metabolic syndrome diagnosis was evaluated according to the metabolic criteria specified in the NCEP ATP-III guideline. 

NCEP ATP- III diagnostic critearia: 

1. Waistline: M > 102 cm, F>88 cm 

2. Trigliseride ≥ 150 mg/dl 

3. HDL – C: M < 40 mg/dl, F < 50 mg/dl 

4. Blood Pressure ≥ 130/85 mmHg 

5. Blood glucose level ≥ 110 mg/dl 

Patients who met 3 or more of the mentioned 5 criteia above were considered to have metabolic syndrome. Consequently; patients were divided into two groups with (Group 1) and without (Group 2) metabolic syndrome.  

Statistical evaluations were performed using SPSS 12.0 computer package program. Differences of categorical data were evaluated with Chi Square test; comparison of paired groups was evaluated with Student-t test or Mann Whitney U test. Pearson's correlation analysis was used to determine the correlation between parameters. Results were expressed as mean ± standard deviation and p < 0.05 values ​​were considered statistically significant. 

Results 

The study group consisted of 109 chronic hepatitis B patients, 41.3% (n=45) of which were female and 58.7% (n=64) were male. The mean age range was 40.9±12.2 (18 -78) years.  

In our study, 41.3% (n=45) of the patients were female and 58.7% (n=64) were male. In the metabolic syndrome positive group, 7 were female and 17 were male. The mean age of patients with chronic hepatitis B and metabolic syndrome was 45±9.1, while the mean age of patients without metabolic syndrome was 39.7±12.7. The mean age of female and male among patients with metabolic syndrome were 43.8±9.35; and 45.86±9.26 respectively. 

Chronic hepatitis diagnoses were confirmed retrospectively by HBsAg positivity lasting longer than 6 months, HBV DNA positivity and liver biopsy.  

In the whole group, the prevalence of metabolic syndrome associated with chronic hepatitis B disease was found to be 22% (n=24). Seventeen patients with metabolic syndrome (70%) were male and 7 patients (30%) were female.  

When the demographic fatures of the patients were compared according to presence of metabolic syndrome, all the features were statistically significantly different between two groups except mean age. The mean BMI, waistline measurement, systolic and diastolic blood pressure of patients in the metabolic syndrome group was significantly higher compared to the patients without metabolic syndrome (p=0.001, p=0.001, p=0.001 and p=0.002 respectively). 

Demographic measurements of both groups were shown in Table 1. 

Table 1. Demographic measurements of patients according to metabolic syndrome status  

The results of the comparison of biochemical parameters in chronic hepatitis B patients with and without metabolic syndrome revealed significant differences for FG, alkaline phosphatase (ALP), Triglyceride (TG) and High-density lipoproteins (HDL). The mean FG, ALP and TG levels were significantly higher in metabolic syndrome (+) patients (p<0.001, p=0.047 and p=0.008 respectively). No statistically significant difference was found in Hgb, total protein, albumin, PTZ-INR, AST, ALT, GGT, LDL-C, total bilirubin, direct bilirubin levels between metabolic syndrome (+) and (-) patients (p>0.05).  The comparison of biochemical parameters of chronic hepatitis B patients with and without metabolic syndrome is shown in Table 2. 

Table 2. Biochemical Features of patients with / without Metabolic Syndrome  

Nine patients in the study group were diagnosed with type 2 DM and all of these patients were receiving subcutaneous insulin therapy for diabetes. Of these 9 patients, 22.2% (n=2) were diagnosed with stage 0-1, 44.4% (n=4) with stage 2-4, and 33.3% (n=3) with stage 5-6 hepatic fibrosis. 

In total, 20% (n=20) of other 100 patients had HOMA-IR >2.7, while 80% (n=80) had HOMA-IR <2.7. When liver biopsies of the 20 patients with insulin resistance were evaluated, 30% (n=6) had stage 0-1; 60% (n=12) had stage 2-4; and 10% (n=2) had stage 5-6 hepatic fibrosis.  

Of 80 patients in whom insulin resistance was not detected according to the insulin resistance formula (HOMA-IR), liver biopsy results revealed stage 0-1, stage 2-4 and stage 5-6 hepatic fibrosis in 7.5% (n=6), 88.8% (n=71), and 3.8% (n=3) respectively.  

When the liver biopsy results of 109 patients in the study group were examined, the histological activity index was 9,67±2.94 in the metabolic syndrome (+) patient group and 8,39±2.69 in the metabolic syndrome (-) patient group (p=0.047). In addition, the fibrosis stage score was 3,08±1.47 in the metabolic syndrome positive group and 2,32±0.86 in the metabolic syndrome negative group (p=0.002). 

When the liver biopsy results of the whole group were evaluated, 63.3% (n=69) were reported as HAI≥7 where 36.7% (n= 40) was HAI<7. Hepatic fibrosis stage of the patients was stage 0-1 in 8.3% (n=9), stage 2-4 in 92% (n=92), and stage 5-6 in 7.3% (n=8) (Table 2). Metabolic syndrome was positive in 1 of 9 patients (11%) in stage 0-1. Metabolic syndrome was positive in 18 of 92 patients (19.5%) in stage 2-4. Metabolic syndrome was positive in 5 of 8 patients (62.5%) with stage 5-6 hepatic fibrosis. The frequency of metabolic syndrome was significantly correlated with hepatic fibrosis stage (p=0.014). 

When the liver biopsy results were evaluated according to metabolic syndrome presence; in patients with metabolic syndrome Stage 0-1 was significantly lower (p=0.027) while Stage 5-6 was reported sifnificantly higher (p=0.004) in this patient group (Table 2).  

Discussion 

Hepatitis B virus (HBV) infection is still a widespread and important health problem worldwide with its potential adverse effects such as chronic hepatitis, cirrhosis and hepatocellular carcinoma and high morbidity and mortality rates despite the new diagnostic and preventive methods used today. It is known that approximately two billion people worldwide are infected with HBV which results in a consequential chronic infection in 400 million of them. Chronic hepatitis B infection has been reported to cause death in an average of 500,000-1,200,000 people per year [14-17]. Metabolic syndrome is a proinflammatory, prothrombotic condition that occurs as a result of the combination of risk factors such as impaired glucose and insulin metabolism, obesity, dyslipidemia and hypertension, which are associated with the development of cardiovascular diseases and Type 2 diabetes. Our results from this study showed the prevalence of metabolic syndrome and its effect on liver fibrosis among chronic HBV patients. The purpose of this study was to find association between metabolic syndrome and liver fibrosis in chronic hepatitis B. The association between chronic viral hepatitis and metabolic syndrome was reported in several previous studies. 

The prevalence of metabolic syndrome is correlated with race, age, gender, BMI, smoking habits, alcohol use, socio-economic level and physical activity. Sedentary lifestyle and unhealthy dietary routine play the most important role in the prevalence of metabolic syndrome. Sanisoglu et al reported that in Turkey, more than one-third (35.08 %) of the participants was obese. The hypertension, diabetes and metabolic syndrome ratios were 13.66 %, 4.16 % and 27.38 %, respectively [18]. 

The lower rate of metabolic syndrome in this study group compared to previous studies conducted in Turkey can be attributed to less common sedentary lifestyle and unhealthy eating habits in the region where this study is evaluated, predominantly male and younger patient population. Additionally, malnutrition can be seen in every period of chronic liver disease, however this factor can be ignored due to the small number of cirrhotic patients in this study group. 

Very few studies evaluated the role of metabolic syndrome in hepatic steatosis and fibrosis and the relationship between nonalcoholic fatty liver disease (NAFLD) and metabolic syndrome. Gangireddy et al published a cross-sectional population-based survey of 4,678 participants [19]. They reported that the adjusted odds ratio for any level of steatosis was 4.12 times higher and any level of fibrosis was 3.34 times higher among participants with metabolic syndrome. Odds ratio for fibrosis without steatosis was found 2.67 times higher in patients with metabolic syndrome. It was concluded that the presence of metabolic syndrome significantly increases the risk of hepatic fibrosis and steatosis [19]. 

The diagnostic criteria for metabolic syndrome include impaired glucose tolerance and diabetes mellitus. DM is a common disease due to increased obesity due to lifestyle and dietary habits [20]. Diabetes is an independent predictor of liver fibrosis in patients with non-alcoholic steatohepatitis. Most patients with severe fibrosis are diabetic [21]. 

Liver cirrhosis is a chronic process characterized by degeneration, regeneration, and fibrosis in the liver parenchyma caused by many diseases [2]. Fibrosis in the liver is a very common condition in chronic viral hepatitis. In addition, mortality in chronic hepatitis patients is almost always due to advanced fibrosis, cirrhosis itself or complications of cirrhosis. 

Oureshi et al. [22] showed that liver cirrhosis occurs more frequently in patients with chronic hepatitis and DM. Impaired glucose tolerance, postprandial hyperglycemia and hyperinsulinemia are also reported in patients with liver cirrhosis [23, 24]. This is reported to be caused by receptor and postreceptor damage in some studies however the authors also mention the need for further studies to elucidate the mechanism of the defect at the cellular level [24-26]. In their study, Caronia et al. [27] reported 23.6% diabetes rate in 1151 patients with HCV related cirrhosis.  

In our study, 9 of the patients were diagnosed with Type 2 DM and all were under insulin treatment. In 88.9% of these patients’ histologic activity index (HAI) was greater than 7. When their stages were examined, 22.2% were stage 0-1, 44.4% were stage 2-4, and 33.3% were stage 5-6. The data obtained from our study also demonstrates more severe fibrosis in patients with DM. 

Obesity is a multifactorial disease with an increasing prevalence, resulting from the accumulation of excess fat tissue in the body. The amount of fat exceeding 25% of total body weight in men and 30% in women is considered as obesity [28]. In our study; the BMI of patients with stage 5-6 was 27.37±1.87, while it was 26.2±4.5 in patients with stage 0-4 which demonstrates a correlation of BMI with advanced stages. 

Increases in the inflammatory process due to insulin resistance plays a key role in the pathogenesis of metabolic syndrome and HBV infection is more severe in individuals affected by diabetes [29-31]. 

The gold standard diagnostic method for insulin resistance is the euglycemic insulin clamp test. The most commonly used method in clinical practice is the HOMA formula and it was stated that HOMA can be used safely in large-scale or epidemiological studies. HOMA-IR is a physiologically based model that measures insulin resistance from fasting glucose and insulin levels [32]. 

In our study we used HOMA-IR for evaluating insulin resistance. When liver biopsies were evaluated, insulin resistance was detected in 30% (n=6) of the patients with stage 0-1; in 60% (n=12) in stage 2-3-4; and in 10% (n=2) in stage 5-6. In 80 patients without insulin resistance according to HOMA-IR, liver biopsies revealed stage 0-1 in 7.5% (n=6), stage 2-4 in 88.8% (n=71), and stage 5-6 in 3.8%. Our results demonstrated a significant association of increased HOMA-IR index with advanced stage fibrosis. 

In the case of insulin resistance, the amount of free fatty acids released from adipose tissue increases [33]. In recent studies in chronic hepatitis C patients, hepatic steatosis is seen to range from 30% to 70% [32, 34, 35]. 

Lipids are one of the fundamental components in the control of cell functions and homeostasis. Therefore, metabolic syndrome NCEP-ATP III criteria include high triglyceride levels. In chronic liver diseases, decreased capacity of synthesisleads to a decrease in triglyceride and cholesterol levels. 

In line with these criteria we found significantly higher TG levels (p=0.008) but low HDL-C levels (p=0.001) in patients with metabolic syndrome.  

Liver biopsy results of our study revealed steatosis in 41.3% (n=45) of the patients. In 24 patients with metabolic syndrome, steatosis was detected in 13 (54%) of patients. Steatosis was observed in 7 (87.5%) of 8 patients with stage 5-6. In line with our results many studies have shown that hepatic fibrosis is associated with insulin resistance, obesity, and hepatic steatosis [36, 37].  

Cirrhotic patients have a hyperdynamic blood circulation with reduced effective circulating volume due to their vasodialated state. Therefore, a hyperdynamic circulation with low systemic vascular resistance and increased cardiac output is seen in these patients. Prabhu et al reported a 7% hypertension prevelance in cirrhotic patients which is lower than general population [38].  

In our study, when liver biopsies of 14 patients diagnosed with hypertension were evaluated, 13 has histological activity index greater than 7.  Two of these patients were stage 5-6 and 12 of them were stage 2-4. To date, the effect of systemic hypertension on hepatic fibrosis is not clearly understood. Unfortunately; due to the small number of hypertensive patients we were also not able to shed light to this issue with the results of this study.  

Metabolic syndrome is accompanied by abnormalities in the coagulation/fibrinolytic system leading to a procoagulant state.  

Although a lower prevalence of hepatic steatosis is reported in chronic hepatitis B patients compared to general population [39] co-existing fatty liver disease in this population is frequently seen in endemic areas. Two prior meta-analysis of 17 and 54 studies, has reported the prevalence of fatty liver about 29.6% and 32.8% respectively in patients with chronic hepatitis B [40, 41]. A more recent larger meta-analysis of 98 studies demonstrated even higher prevalence of 34.93% [42]  

In conclusion, metabolic syndrome in chronic hepatitis B infection is a factor that increases liver fibrosis. Early recognition of metabolic syndrome in chronic hepatitis B patients will provide early therapeutic interventions targeting metabolic syndrome. Lose weight, glycemic control, and antihypertensive and anti-lipid treatment when necessary is adviced in patients who have chronic hepatitis B with metabolic syndrome.