Histological progression of non-alcoholic fatty liver disease in Chinese patients

Global epidemiology of type 2 diabetes in patients with NAFLD or MAFLD: a systematic review and meta-analysis

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) and metabolic-associated fatty liver disease (MAFLD) shares common pathophysiological mechanisms with type 2 diabetes, making them significant risk factors for type 2 diabetes. The present study aimed to assess the epidemiological feature of type 2 diabetes in patients with NAFLD or MAFLD at global levels.

METHODS

Published studies were searched for terms that included type 2 diabetes, and NAFLD or MAFLD using PubMed, EMBASE, MEDLINE, and Web of Science databases from their inception to December 2022. The pooled global and regional prevalence and incidence density of type 2 diabetes in patients with NAFLD or MAFLD were evaluated using random-effects meta-analysis. Potential sources of heterogeneity were investigated using stratified meta-analysis and meta-regression.

RESULTS

A total of 395 studies (6,878,568 participants with NAFLD; 1,172,637 participants with MAFLD) from 40 countries or areas were included in the meta-analysis. The pooled prevalence of type 2 diabetes among NAFLD or MAFLD patients was 28.3% (95% confidence interval 25.2-31.6%) and 26.2% (23.9-28.6%) globally. The incidence density of type 2 diabetes in NAFLD or MAFLD patients was 24.6 per 1000-person year (20.7 to 29.2) and 26.9 per 1000-person year (7.3 to 44.4), respectively.

CONCLUSIONS

The present study describes the global prevalence and incidence of type 2 diabetes in patients with NAFLD or MAFLD. The study findings serve as a valuable resource to assess the global clinical and economic impact of type 2 diabetes in patients with NAFLD or MAFLD.

Disease State Transition Probabilities Across the Spectrum of NAFLD: A Systematic Review and Meta-Analysis of Paired Biopsy or Imaging Studies

BACKGROUND & AIMS

We conducted a meta-analysis to summarize the rates of progression to and regression of nonalcoholic fatty liver (NAFL), nonalcoholic steatohepatitis (NASH), and fibrosis in adults with nonalcoholic fatty liver disease (NAFLD).

METHODS

We searched PubMed/Medline and 4 other databases from 1985 through 2020. We included observational studies and randomized controlled trials in any language that used liver biopsy or imaging to diagnose NAFLD in adults with a follow-up period ≥48 weeks. Rates were calculated as incident cases per 100 person-years and pooled using the random-effects Poisson distribution model. Heterogeneity was assessed using the I2 statistic.

RESULTS

We screened 9744 articles and included 54 studies involving 26,738 patients. Among observational studies, 20% of healthy adults developed NAFL (incidence rate, 4.8/100 person-years) while 21% of people with fatty liver had resolution of NAFL (incidence rate, 2.4/100 person-years) after a median of approximately 4.5 years. In addition, 31% of patients developed NASH after 4.7 years (incidence rate, 7.4/100 person-years), whereas in 29% of those with NASH, resolution occurred after a median of 3.5 years (incidence rate, 5.1/100 person-years). Time to progress by 1 fibrosis stage was 9.9, 10.3, 13.3, and 22.2 years for F0, F1, F2, and F3, respectively. Time to regress by 1 stage was 21.3, 12.5, 20.4, and 40.0 years for F4, F3, F2, and F1, respectively. Rates estimated from randomized controlled trials were higher than those from observational studies.

CONCLUSIONS

In our meta-analysis, progression to NASH was more common than regression from NASH. Rates of fibrosis progression were similar across baseline stage, but patients with advanced fibrosis were more likely to regress than those with mild fibrosis.

Nonalcoholic Fatty Liver Disease Is a Precursor of New-Onset Metabolic Syndrome in Metabolically Healthy Young Adults

Nonalcoholic fatty liver disease (NAFLD) is associated with metabolic syndrome (MetS). However, the temporal relationship between NAFLD and MetS has yet to be evaluated, especially in young adults. In this study, we investigated whether NAFLD could be a precursor for MetS in metabolically healthy young adults. Using the Korean nationwide health screening database, we analyzed subjects aged 20–39 years who were free from any component of MetS between 2009 and 2012. A total of 1,659,192 subjects without excessive alcohol consumption or concomitant liver disease were categorized into three groups according to the fatty liver index (FLI): (1) NAFLD (FLI ≥ 60); (2) borderline NAFLD (30 ≤ FLI < 60); and (3) control (FLI < 30). During the 6,699,462 person-years of follow-up, 109,239 subjects developed MetS (16.3 per 1000-person-years). The NAFLD group and the borderline NAFLD group were associated with a higher risk of MetS than the control group (incidence rate ratios, 2.9 (95% confidence interval (CI), 2.7–3.1) for the NAFLD group and 2.1 (95% CI, 2.1–2.2) for the borderline NAFLD group, respectively). In addition, all of the metabolic components were positively associated with FLI in a proportional manner. NAFLD is associated with the future onset of MetS in young adults. Therefore, active lifestyle intervention is required for young adults diagnosed with NAFLD to prevent MetS and other metabolic diseases.

Platelet-Activating Factor Promotes the Development of Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is a multifaceted clinicopathological syndrome characterised by excessive hepatic lipid accumulation that causes steatosis, excluding alcoholic factors. Platelet-activating factor (PAF), a biologically active lipid transmitter, induces platelet activation upon binding to the PAF receptor. Recent studies have found that PAF is associated with gamma-glutamyl transferase, which is an indicator of liver disease. Moreover, PAF can stimulate hepatic lipid synthesis and cause hypertriglyceridaemia. Furthermore, the knockdown of the PAF receptor gene in the animal models of NAFLD helped reduce the inflammatory response, improve glucose homeostasis and delay the development of NAFLD. These findings suggest that PAF is associated with NAFLD development. According to reports, patients with NAFLD or animal models have marked platelet activation abnormalities, mainly manifested as enhanced platelet adhesion and aggregation and altered blood rheology. Pharmacological interventions were accompanied by remission of abnormal platelet activation and significant improvement in liver function and lipids in the animal model of NAFLD. These confirm that platelet activation may accompany a critical importance in NAFLD development and progression. However, how PAFs are involved in the NAFLD signalling pathway needs further investigation. In this paper, we review the relevant literature in recent years and discuss the role played by PAF in NAFLD development. It is important to elucidate the pathogenesis of NAFLD and to find effective interventions for treatment.

Management of Cardiometabolic Complications in Patients With Nonalcoholic Fatty Liver Disease: A Review of the Literature With Recommendations

Nonalcoholic fatty liver disease (NAFLD) comprises a spectrum of liver conditions characterized by significant lipid deposition within hepatocytes. As an overarching diagnosis, NAFLD contains a continuum of progressive liver diseases ranging from isolated liver steatosis to necroinflammatory states leading to end-stage liver disease. Nonalcoholic fatty liver and nonalcoholic steatohepatitis are distinguished by their histologic patterns, with the former exhibiting steatosis without fibrosis or inflammation. This important distinction provides clinicians a timeline within the NAFLD staging to target appropriate interventions against modifiable risk factors. NAFLD is likely formed in response to metabolic imbalances that damage the livers adaptive capacity. Metabolic conditions leading to steatosis mirror common cardiovascular risk factors, including dyslipidemia, diabetes mellitus, and obesity. Acknowledging the common risk factors for development and progression of NAFLD, it is unsurprising the first-line management focuses on the treatment of metabolic syndrome with an emphasis on weight reduction in obese populations. The purpose of this review is to provide a detailed summary of the literature as well as outline the current treatment recommendations for patients with NAFLD with a detailed focus on pharmacologic antiobesity interventions.

Established and emerging factors affecting the progression of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) has become the most common chronic liver disease affecting approximately 25% of the global population. Although a majority of NAFLD patients will never experience liver-related symptoms it is estimated that 5-10% will develop cirrhosis-related complications with risk of death or need for liver transplantation. NAFLD is closely associated with cardiovascular disease and components of the metabolic syndrome. However, NAFLD is not uncommon in lean individuals and may in these subjects represent a different entity with separate pathophysiological mechanisms involved implying a higher risk for development of end-stage liver disease. There is considerable fluctuation in the histopathological course of NAFLD that may partly be attributed to lifestyle factors and dietary composition. Nutrients such as fructose, monounsaturated fatty acids, and trans-fatty acids may aggravate NAFLD. Presence of type 2 diabetes mellitus seems to be the most important clinical predictor of liver-related morbidity and mortality in NAFLD. Apart from severity of the metabolic syndrome, genetic polymorphisms and environmental factors, such as moderate alcohol consumption, may explain the variation in histopathological and clinical outcome among NAFLD patients.

Peroxisomal oxidation of erucic acid suppresses mitochondrial fatty acid oxidation by stimulating malonyl-CoA formation in the rat liver

Feeding of rapeseed (canola) oil with a high erucic acid concentration is known to cause hepatic steatosis in animals. Mitochondrial fatty acid oxidation plays a central role in liver lipid homeostasis, so it is possible that hepatic metabolism of erucic acid might decrease mitochondrial fatty acid oxidation. However, the precise mechanistic relationship between erucic acid levels and mitochondrial fatty acid oxidation is unclear. Using male Sprague-Dawley rats, along with biochemical and molecular biology approaches, we report here that peroxisomal β-oxidation of erucic acid stimulates malonyl-CoA formation in the liver and thereby suppresses mitochondrial fatty acid oxidation. Excessive hepatic uptake and peroxisomal β-oxidation of erucic acid resulted in appreciable peroxisomal release of free acetate, which was then used in the synthesis of cytosolic acetyl-CoA. Peroxisomal metabolism of erucic acid also remarkably increased the cytosolic NADH/NAD⁺ ratio, suppressed sirtuin 1 (SIRT1) activity, and thereby activated acetyl-CoA carboxylase, which stimulated malonyl-CoA biosynthesis from acetyl-CoA. Chronic feeding of a diet including high-erucic-acid rapeseed oil diminished mitochondrial fatty acid oxidation and caused hepatic steatosis and insulin resistance in the rats. Of note, administration of a specific peroxisomal β-oxidation inhibitor attenuated these effects. Our findings establish a cross-talk between peroxisomal and mitochondrial fatty acid oxidation. They suggest that peroxisomal oxidation of long-chain fatty acids suppresses mitochondrial fatty acid oxidation by stimulating malonyl-CoA formation, which might play a role in fatty acid-induced hepatic steatosis and related metabolic disorders.

Epidemiological differences of common liver conditions between Asia and the West

Liver diseases form a heterogenous group of acute and chronic disorders of varying etiologies. Not only do they result in significant morbidity and mortality, but they also lead to a marked reduction in quality of life, together with a high socioeconomic burden globally. A better understanding of their global distribution is necessary to curb the massive health-care and socioeconomic burden that they entail. Notable differences and similarities have been described between common liver disease conditions occurring in Asia and the West (Europe and North America), giving rise to the need for an updated collective appraisal of this subject. In this review, the epidemiological differences of common liver conditions, specifically acute liver failure, drug-induced liver injury, acute-on-chronic liver failure, hepatocellular carcinoma, and non-alcoholic fatty liver disease, between Asia and the West are discussed.

Clinical features and treatment of nonalcoholic fatty liver disease across the Asia Pacific region-the GO ASIA initiative

BACKGROUND

The Gut and Obesity Asia (GO ASIA) workgroup was formed to study the relationships between obesity and gastrointestinal diseases in the Asia Pacific region.

AIM

To study factors associated with nonalcoholic steatohepatitis (NASH) and advanced fibrosis, and medical treatment of biopsy-proven nonalcoholic fatty liver disease (NAFLD) patients.

METHODS

Retrospective study of biopsy-proven NAFLD patients from centres in the GO ASIA Workgroup. Independent factors associated with NASH and with advanced fibrosis on binary logistic regression analyses in a training cohort were used for the development of their corresponding risk score, which were validated in a validation cohort.

RESULTS

We included 1008 patients from nine centres across eight countries (NASH 62.9%, advanced fibrosis 17.2%). Independent predictors of NASH were body mass index ≥30 kg/m² , diabetes mellitus, dyslipidaemia, alanine aminotransferase ≥88 U/L and aspartate aminotransferase ≥38 U/L, constituting the Asia Pacific NASH risk score. A high score has a positive predictive value of 80%-83% for NASH. Independent predictors of advanced fibrosis were age ≥55 years, diabetes mellitus and platelet count <150 × 10⁹ /L, constituting the Asia-Pacific NAFLD advanced fibrosis risk score. A low score has a negative predictive value of 95%-96% for advanced fibrosis. Only 1.7% of patients were referred for structured lifestyle program, 4.2% were on vitamin E, and 2.4% were on pioglitazone.

CONCLUSIONS

More severe liver disease can be suspected or ruled out based on factors identified in this study. Utilisation of structured lifestyle program, vitamin E and pioglitazone was limited despite this being a cohort of biopsy-proven NAFLD patients with majority of patients having NASH.

Centrilobular ductular reaction correlates with fibrosis stage and fibrosis progression in non-alcoholic steatohepatitis

There is increasing interest in the role of ductular reaction as part of the pathogenesis and characteristic histology of non-alcoholic steatohepatitis. However, earlier studies did not separately assess the contribution of periportal and centrilobular zone ductular reaction over the spectrum of non-alcoholic steatohepatitis, and their clinical significance remains unclear. We herein analyzed the character of ductular reaction in each hepatic zone in non-alcoholic steatohepatitis biopsies and for the first time evaluated the prognostic value of ductular reaction in baseline biopsies as a predictor of progression of fibrosis in subsequent biopsies. A total of 90 non-alcoholic steatohepatitis liver biopsies were included in the cohort. The relationships among ductular reaction, grade, stage, and other common histopathologic findings in non-alcoholic steatohepatitis were analyzed in a cross-sectional manner. Among these patients, a total of 47 patients underwent sequential liver biopsies in the absence of effective treatment. The frequency of ductular reaction and the other histopathologic parameters in the initial biopsies were analyzed as predictors of progression of fibrosis in the second biopsies in a longitudinal analysis. Centrilobular ductular reaction was identified in 90% of patients and 38% of centrilobular zones. The prevalence of centrilobular ductular reaction increased as non-alcoholic steatohepatitis grade increased (P=0.0002) and also as stage of fibrosis increased (P<0.0001) in the cross-sectional study. In the longitudinal study, the frequency of centrilobular ductular reaction in the initial biopsies was significantly higher in the group of progressors and correlated with the rate of fibrosis progression (P=0.02). Centrilobular ductular reaction is common in non-alcoholic steatohepatitis and its presence correlates significantly with increasing necroinflammatory activity and fibrosis stage. Development of centrilobular ductular reaction appears to predict progression of fibrosis in subsequent biopsies.

Natural history of nonalcoholic fatty liver disease: A prospective follow-up study with serial biopsies

Nonalcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease in the world. The complete natural history of NAFLD is unknown because few high‐quality follow‐up studies have been conducted. Our aim was to find variables predicting disease severity through an extended follow‐up with serial biopsies. In a prospective cohort study, 129 patients who enrolled between 1988 and 1993 were asked to participate in a follow‐up study on two occasions; biochemical, clinical, and histologic data were documented. The mean time between biopsies was 13.7 (±1.7) and 9.3 (±1.0) years, respectively. At the end of the study period, 12 patients (9.3%) had developed end‐stage liver disease and 34% had advanced fibrosis. Out of the 113 patients with baseline low fibrosis (<3), 16% developed advanced fibrosis. Fibrosis progression did not differ among the different stages of baseline fibrosis (P = 0.374). Fifty‐six patients (43%) had isolated steatosis, of whom 9% developed advanced fibrosis (3 patients with biopsy‐proven fibrosis stage F3‐F4 and 2 patients with end‐stage liver disease). Fibrosis stage, ballooning, and diabetes were more common in patients who developed end‐stage liver disease; however, there were no baseline clinical, histologic, or biochemical variables that predicted clinical significant disease progression. Conclusion: NAFLD is a highly heterogeneous disease, and it is surprisingly hard to predict fibrosis progression. Given enough time, NAFLD seems to have a more dismal prognosis then previously reported, with 16% of patients with fibrosis stage <3 developing advanced fibrosis and 9.3% showing signs of end‐stage liver disease. (Hepatology Communications 2018;2:199–210)

Serum thymosin beta4 as a noninvasive biomarker in patients with nonalcoholic steatohepatitis

OBJECTIVE

The aim of the study was to determine whether serum thymosin beta4 (Tβ4) can be a useful noninvasive biomarker to differentiate between nonalcoholic steatohepatitis (NASH) and nonalcoholic fatty liver (NAFL).

METHODS

The study included 24 NAFL patients and 21 NASH patients. The levels of Tβ4, 8-hydroxydeoxyguanosine acid (8-OhdG), liver function parameters, blood lipid, and glucose were detected in the venous blood of all patients. The NAFLD histological activity score (NAS) was examined in biopsy specimens from all patients. Statistical analysis was performed in order to find differences between the two abovementioned groups. In addition, receiver operator characteristic (ROC) analyses for alanine aminotransferase (ALT) and Tβ4 levels were performed in NAFL and NASH patients and the cut-off value was determined. Associations between the variables were tested using correlation coefficient calculations. Statistical significance was set at a p value of < 0.05.

RESULTS

Serum Tβ4 content was 5.12 ± 1.87 mg/l in the NAFL group and 2.98 ± 1.35 mg/l in the NASH group (p < 0.001). Serum Tβ4 content and NAS, histological features of hepatic steatosis, lobular inflammation and ballooning, ALT, glucose and 8-OhdG levels were negatively correlated (p < 0.05 for all) in the NASH group. The correlation coefficient values were -0.530, -0.562, -0.574, -0.438, -0.446, -0.426 and -0.563, respectively. On the basis of ROC analysis, the best predictive Tβ4 cut-off value for detecting NASH was 3.94 mg/l (85.7% sensitivity and 79.2% specificity, which were higher than those of ALT).

CONCLUSION

Serum Tβ4 level can be used as a biomarker for the diagnosis of NASH and was negatively correlated with the oxidation state of the liver.

Natural History of NAFLD/NASH

Purpose of Review

The purpose of this review is to summarize the latest knowledge on the natural history of non-alcoholic fatty liver disease (NAFLD). The review focuses on mortality, liver-related complications, and histological course.

Recent Findings

Studies during the last decade have established NAFLD as a potentially progressive liver disease. Age and diabetes are the strongest clinical predictors of progressive disease. Fibrosis stage is the most important histological variable to predict mortality and liver-related complications. So far, no study has been able to show that non-alcoholic steatohepatitis at baseline predicts mortality or future liver-related complications when adjusting for fibrosis.

Summary

The outlines of the natural history of NAFLD have become clearer during the last decade. There is limited data on factors that predict clinical progression. Prospective longitudinal studies are needed to help us predict worse outcome in individual patients.

Non-alcoholic fatty liver disease: An expanded review

Non-alcoholic fatty liver disease (NAFLD) encompasses the simple steatosis to more progressive steatosis with associated hepatitis, fibrosis, cirrhosis, and in some cases hepatocellular carcinoma. NAFLD is a growing epidemic, not only in the United States, but worldwide in part due to obesity and insulin resistance leading to liver accumulation of triglycerides and free fatty acids. Numerous risk factors for the development of NAFLD have been espoused with most having some form of metabolic derangement or insulin resistance at the core of its pathophysiology. NAFLD patients are at increased risk of liver-related as well as cardiovascular mortality, and NAFLD is rapidly becoming the leading indication for liver transplantation. Liver biopsy remains the gold standard for definitive diagnosis, but the development of noninvasive advanced imaging, biochemical and genetic tests will no doubt provide future clinicians with a great deal of information and opportunity for enhanced understanding of the pathogenesis and targeted treatment. As it currently stands several medications/supplements are being used in the treatment of NAFLD; however, none seem to be the "magic bullet" in curtailing this growing problem yet. In this review we summarized the current knowledge of NAFLD epidemiology, risk factors, diagnosis, pathogenesis, pathologic changes, natural history, and treatment in order to aid in further understanding this disease and better managing NAFLD patients.

Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) comprises a disease spectrum ranging from benign hepatic steatosis to non-alcoholic steatohepatitis with inflammation (NASH) and liver cirrhosis. NAFLD is now recognised as the hepatic manifestation of the metabolic syndrome. Simple steatosis is benign, whereas NASH can progress to cirrhosis with its resultant complications. Liver biopsy remains the gold standard in the diagnosis of NAFLD/NASH. Lifestyle and dietary modifications to achieve sustained weight loss is the cornerstone of NAFLD/NASH treatment.

Nonalcoholic Steatohepatitis

Nonalcoholic steatohepatitis (NASH) has become a major cause of cirrhosis and liver-related deaths worldwide. NASH is strongly associated with obesity and the metabolic syndrome, conditions that cause lipid accumulation in hepatocytes (hepatic steatosis). It is not well understood why some, but not other, individuals with hepatic steatosis develop NASH. The factors that determine whether or not NASH progresses to cirrhosis are also unclear. This review summarizes key components of NASH pathogenesis and discusses how inherent and acquired variations in regulation of these processes impact the risk for NASH and NASH cirrhosis.

Screening diabetic patients for non-alcoholic fatty liver disease with controlled attenuation parameter and liver stiffness measurements: a prospective cohort study

OBJECTIVE

Type 2 diabetes is an important risk factor for non-alcoholic fatty liver disease (NAFLD), but current guidelines provide conflicting recommendations on whether diabetic patients should be screened for NAFLD. We therefore studied the strategy of screening diabetic patients by FibroScan.

DESIGN

Liver fat and fibrosis were assessed by controlled attenuation parameter (CAP) and liver stiffness measurements (LSM) by FibroScan at a diabetic centre for patients from primary care and hospital clinics. Probe-specific LSM cut-offs were used to detect advanced fibrosis.

RESULTS

Of 1918 patients examined, 1799 (93.8%) had valid CAP and 1884 (98.2%) had reliable LSM (1770 with the M probe and 114 with the XL probe). The proportion of patients with increased CAP and LSM was 72.8% (95% CI 70.7% to 74.8%) and 17.7% (95% CI 16.0% to 19.5%), respectively. By multivariable analysis, female gender, higher body mass index, triglycerides, fasting plasma glucose and alanine aminotransferase (ALT) and non-insulin use were associated with increased CAP. Longer duration of diabetes, higher body mass index, increased ALT and spot urine albumin:creatinine ratio and lower high-density lipoprotein-cholesterol were associated with increased LSM. Ninety-four patients (80% had increased LSM) underwent liver biopsy: 56% had steatohepatitis and 50% had F3-4 disease.

CONCLUSIONS

Diabetic patients have a high prevalence of NAFLD and advanced fibrosis. Those with obesity and dyslipidaemia are at particularly high risk and may be the target for liver assessment. Our data support screening for NAFLD and/or advanced fibrosis in patients with type 2 diabetes.

The Natural Course of Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent form of chronic liver disease in the world, paralleling the epidemic of obesity and Type 2 diabetes mellitus (T2DM). NAFLD exhibits a histological spectrum, ranging from “bland steatosis” to the more aggressive necro-inflammatory form, non-alcoholic steatohepatitis (NASH) which may accumulate fibrosis to result in cirrhosis. Emerging data suggests fibrosis, rather than NASH per se, to be the most important histological predictor of liver and non-liver related death. Nevertheless, only a small proportion of individuals develop cirrhosis, however the large proportion of the population affected by NAFLD has led to predictions that NAFLD will become a leading cause of end stage liver disease, hepatocellular carcinoma (HCC), and indication for liver transplantation. HCC may arise in non-cirrhotic liver in the setting of NAFLD and is associated with the presence of the metabolic syndrome (MetS) and male gender. The MetS and its components also play a key role in the histological progression of NAFLD, however other genetic and environmental factors may also influence the natural history. The importance of NAFLD in terms of overall survival extends beyond the liver where cardiovascular disease and malignancy represents additional important causes of death.

Natural History of Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) remains among the most common liver diseases worldwide, with increasing prevalence in concert with the obesity and metabolic syndrome epidemic. The evidence on the natural history, albeit with some ambiguity, suggests the potential for some subsets of NAFLD to progress to cirrhosis, liver-related complications and mortality with fibrosis being the most important predictor of hard long-term endpoints such as mortality and liver complications. In this setting, NAFLD proves to be a formidable disease entity, with considerable clinical burden, for both the present and the future. Our understanding of the natural history of NAFLD is constantly evolving, with nascent data challenging current dogma. Further clarification of the natural history is required with well-designed, well-defined studies using prospectively collected data. Identifying the predictors of long-term outcomes should be used to direct development of clinical trial endpoints in NAFLD.

Histology of Nonalcoholic Fatty Liver Disease and Nonalcoholic Steatohepatitis in Adults and Children

Nonalcoholic fatty liver disease (NAFLD) is the liver disease associated with obesity, diabetes, and the metabolic syndrome. Although steatosis is a key histologic feature, liver biopsies of patients with NAFLD can show a wide range of findings. Nonalcoholic steatohepatitis (NASH) is a progressive subtype of NAFLD first defined by analogy to alcoholic hepatitis. Young children may have an alternate pattern of progressive NAFLD characterized by a zone 1 distribution of steatosis, inflammation, and fibrosis. Several grading and staging systems exist, but all require adequate biopsies. Although NASH generally shows fibrosis progression over time, some patients show regression of disease.

Cost-utility analysis of nonalcoholic steatohepatitis screening

OBJECTIVES

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease in Western countries. No studies have examined the cost-effectiveness of screening its advanced form, nonalcoholic steatohepatitis (NASH).

METHODS

We performed a cost-utility analysis of annual noninvasive screening strategies using third-party payer perspective in a general population in comparison to screening a high-risk obese or diabetic population. Screening algorithms involved well-studied techniques, including NAFLD fibrosis score, transient elastography (TE), and acoustic radiation force impulse (ARFI) imaging for detecting advanced fibrosis (≥ F3); and plasma cytokeratin (CK)-18 for NASH detection. Liver biopsy and magnetic resonance elastography (MRE) were compared as confirmation methods. Canadian dollar (CAD or C$) costs were adjusted for inflation and discounted at 5%. Incremental cost-effectiveness ratio (ICER) of ≤C$ 50,000 was considered cost-effective.

RESULTS

Compared with no screening, screening with NAFLD fibrosis score/TE/CK-18 algorithm with MRE as confirmation for advanced fibrosis had an ICER of C$ 26,143 per quality-adjusted life year (QALY) gained. Screening in high-risk obese or diabetic populations was more cost-effective, with an ICER of C$ 9,051 and C$ 7,991 per quality-adjusted life-year (QALY) gained, respectively. Liver biopsy confirmation was not found to be cost-effective.

CONCLUSIONS

Our model suggests that annual NASH screening in high-risk obese or diabetic populations can be cost-effective.

KEY POINTS

• This cost-utility analysis suggests that screening for nonalcoholic steatohepatitis may be cost-effective. • In particular, screening of high-risk obese or diabetic populations is more cost-effective. • Magnetic resonance elastography was more cost-effective to confirm disease compared to biopsy. • More studies are needed to determine quality of life in nonalcoholic steatohepatitis. • More management strategies for nonalcoholic steatohepatitis are also needed.

Management and diagnosis of fatty liver disease

Nonalcoholic fatty liver disease is a common cause of chronic liver disease and has been an increasingly studied topic of research as the obesity epidemic has been growing. There is a significant morbidity and mortality with uncontrolled steatohepatitis, which can progress to fibrosis, cirrhosis and hepatocellular carcinoma. The prevalence of this disease has been estimated to be roughly one-third of the western population, thought to be largely due to diet and sedentary lifestyle. Several treatments have been studied including vitamin E, insulin-sensitizing agents and ursodeoxycholic acid; however, the only treatment shown to improve the histologic changes of nonalcoholic fatty liver disease is weight loss. Given the proven benefit of weight loss, there may be reason to screen at-risk populations; however, limited availability of other disease-modifying treatments may limit the cost-benefit ratios. A better understanding of the diagnosis and management of this condition is required to alter the course of this modifiable disease.

A CONSORT-compliant, randomized, double-blind, placebo-controlled pilot trial of purified anthocyanin in patients with nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is a common liver disease that can progress to cirrhosis and liver failure. Anthocyanin, a member of the flavonoid family, has been shown to ameliorate NAFLD-associated pathologies in rodents.The aim of this CONSORT-compliant pilot study is to evaluate the effects of anthocyanin supplementation on insulin resistance and liver injury biomarkers in patients with NAFLD.A total of 74 subjects with NAFLD were divided into 2 groups in this double-blind, randomized study. Patients received either purified anthocyanin (320 mg/d) derived from bilberry and black currant or placebo for 12 weeks. Diet, physical activity, anthropometric parameters, glucose tolerance, and a set of biomarkers related to NAFLD were evaluated before and after intervention.No significant differences were observed in nutrient intake, physical activity, anthropometric parameters, or plasma lipid profile between patients receiving anthocyanin or placebo. Compared to controls, the anthocyanin group exhibited significant decreases (P < 0.05, all comparisons) in plasma alanine aminotransferase (-19.1% vs 3.1%), cytokeratin-18 M30 fragment (-8.8% vs 5.6%) and myeloperoxidase (-75.0% vs -44.8%). Significant decreases from baseline in fasting blood glucose and homeostasis model assessment for insulin resistance were observed in the anthocyanin group; however, these differences were not significant relative to placebo controls. In addition, the oral glucose tolerance test indicated that anthocyanin supplementation significantly decreased the 2-hour loading glucose level compared to control (-18.7% vs -3.8%, P = 0.02).A 12-week supplement of purified anthocyanin improved insulin resistance, indicators of liver injury, and clinical evolution in NAFLD patients. Further studies are warranted to determine the clinical applications of anthocyanin in NAFLD.This trial was registered at clinicaltrials.gov as NCT01940263.

Fibrosis progression in nonalcoholic fatty liver vs nonalcoholic steatohepatitis: a systematic review and meta-analysis of paired-biopsy studies

BACKGROUND & AIMS

Little is known about differences in rates of fibrosis progression between patients with nonalcoholic fatty liver (NAFL) vs nonalcoholic steatohepatitis (NASH). We conducted a systematic review and meta-analysis of all studies that assessed paired liver biopsy specimens to estimate the rates of fibrosis progression in patients with nonalcoholic fatty liver disease (NAFLD) including NAFL and NASH.

METHODS

Through a systematic search of multiple databases and author contact, up to June 2013, we identified studies of adults with NAFLD that collected paired liver biopsy specimens at least 1 year apart. From these, we calculated a pooled-weighted annual fibrosis progression rate (number of stages changed between the 2 biopsy samples) with 95% confidence intervals (CIs), and identified clinical risk factors associated with progression.

RESULTS

We identified 11 cohort studies including 411 patients with biopsy-proven NAFLD (150 with NAFL and 261 with NASH). At baseline, the distribution of fibrosis for stages 0, 1, 2, 3, and 4 was 35.8%, 32.5%, 16.7%, 9.3%, and 5.7%, respectively. Over 2145.5 person-years of follow-up evaluation, 33.6% had fibrosis progression, 43.1% had stable fibrosis, and 22.3% had an improvement in fibrosis stage. The annual fibrosis progression rate in patients with NAFL who had stage 0 fibrosis at baseline was 0.07 stages (95% CI, 0.02-0.11 stages), compared with 0.14 stages in patients with NASH (95% CI, 0.07-0.21 stages). These findings correspond to 1 stage of progression over 14.3 years for patients with NAFL (95% CI, 9.1-50.0 y) and 7.1 years for patients with NASH (95% CI, 4.8-14.3 y).

CONCLUSIONS

Based on a meta-analysis of studies of paired liver biopsy studies, liver fibrosis progresses in patients with NAFL and NASH.

Diagnosis and classification of non-alcoholic fatty liver disease and non-alcoholic steatohepatitis: Current concepts and remaining challenges

The high prevalence of non-alcoholic fatty liver disease (NAFLD) has made the condition an important public health issue. Two clinical entities are manifestations of NAFLD, namely, non-alcoholic fatty liver (NAFL) and non-alcoholic steatohepatitis (NASH). The former tends to be benign and non-progressive while the latter can progress to cirrhosis, which in rare cases gives rise to hepatocellular carcinoma. The diagnosis of NAFLD is based on: (i) a history of no or limited daily alcohol intake (<20 g for women and <30 g for men); (ii) presence of hepatic steatosis by imaging or by histology; and (iii) exclusion of other liver diseases. NAFL is defined histologically by the presence of bland, primarily macrovesicular, hepatocellular fatty change, while NASH features fatty change with inflammation and evidence of hepatocyte injury, such as ballooning degeneration. Presence of fibrosis is a sign of chronicity. Thus, the diagnosis of NAFL/NASH rests on clinicopathological criteria; it always requires both clinical and biopsy-based information. NAFLD could be both the result and the cause of metabolic syndrome, with a vicious cycle operating between these conditions. Remaining challenges are: (i) the lack of a clear threshold alcohol intake for defining "non-alcoholic"; (ii) a lacking consensus for the classification of fatty liver disease; and (iii) absence of a histological definition of NASH, which currently remains the gold standard for the diagnosis. Further challenges include the overlap of the criteria for NAFLD and alcoholic liver disease as many obese individuals also consume considerable volumes of alcohol.

Progression of liver disease in non-alcoholic fatty liver disease: a prospective clinicopathological follow-up study

OBJECTIVE

To perform a follow-up study on non-alcoholic fatty liver disease (NAFLD) patients in our previous study using paired liver biopsy.

METHODS

Patients who were included in our previous study on NAFLD and agreed to receive a repeat liver biopsy were included in the study. Their clinical characteristics, laboratory examination results and histological analysis on the repeat liver biopsied specimens were prospectively collected and compared with those in the previous study.

RESULTS

Data from 35 patients (mean age 47.5 ± 10.9 years, male 40.0%) were analyzed. The mean interval between the liver biopsies was 6.4 ± 0.8 years. NAFLD activity score (NAS) worsened in 13, remained unchanged in 9 and ameliorated in 13. Fibrosis worsened in 18 and remained unchanged in 17. Two patients who were confirmed with cirrhosis at baseline developed decompensated cirrhosis. On multivariate analysis, elevated serum aspartate aminotransferase (AST) (odds ratio [OR] 10.74, 95% confidence interval [CI] 1.00-115.86, P = 0.050) and γ-glutamyl transpeptidase (γ-GT) (OR 16.10, 95% CI 1.30-198.90, P = 0.030) at follow-up were associated with worsened NAS. Patients with borderline NASH at baseline were more likely to have worsened NAS at follow-up than those with definite NASH (OR 12.67, 95% CI 2.29-70.02, P = 0.004). However, both groups had a similar likelihood of having worsened fibrosis at follow-up. No plausible factors were found to be associated with worsened fibrosis.

CONCLUSIONS

NAFLD patients with persistently elevated serum AST and γ-GT levels during follow-up should be suspected of having worsened NAS. NASH patients can have significant disease progression over a relatively short period of time and fibrosis might be irreversible without specific interventions.

An Intimate Relationship between ROS and Insulin Signalling: Implications for Antioxidant Treatment of Fatty Liver Disease

Oxidative stress damages multiple cellular components including DNA, lipids, and proteins and has been linked to pathological alterations in nonalcoholic fatty liver disease (NAFLD). Reactive oxygen species (ROS) emission, resulting from nutrient overload and mitochondrial dysfunction, is thought to be a principal mediator in NAFLD progression, particularly toward the development of hepatic insulin resistance. In the context of insulin signalling, ROS has a dual role, as both a facilitator and inhibitor of the insulin signalling cascade. ROS mediate these effects through redox modifications of cysteine residues affecting phosphatase enzyme activity, stress-sensitive kinases, and metabolic sensors. This review highlights the intricate relationship between redox-sensitive proteins and insulin signalling in the context of fatty liver disease, and to a larger extent, the importance of reactive oxygen species as primary signalling molecules in metabolically active cells.

Systematic review with meta-analysis: non-invasive assessment of non-alcoholic fatty liver disease--the role of transient elastography and plasma cytokeratin-18 fragments

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) affects 15-40% of the general population. Some patients have non-alcoholic steatohepatitis (NASH) and progressive fibrosis, and would be candidates for monitoring and treatment.

AIM

To review current literature on the use of non-invasive tests to assess the severity of NAFLD.

METHODS

Systematic literature searching identified studies evaluating non-invasive tests of NASH and fibrosis using liver biopsy as the reference standard. Meta-analysis was performed for areas with adequate number of publications.

RESULTS

Serum tests and physical measurements like transient elastography (TE) have high negative predictive value (NPV) in excluding advanced fibrosis in NAFLD patients. The NAFLD fibrosis score comprises of six routine clinical parameters and has been endorsed by current American guidelines as a screening test to exclude low-risk individuals. The pooled sensitivities and specificities for TE to diagnose F ≥ 2, F ≥ 3 and F4 disease were 79% and 75%, 85% and 85%, and 92% and 92% respectively. Liver stiffness measurement often fails in obese patients, but the success rate can be improved with the use of the XL probe. A number of biomarkers have been developed for the diagnosis of NASH, but few were independently validated. Serum/plasma cytokeratin-18 fragments have been most extensively evaluated and have a pooled sensitivity of 66% and specificity of 82% in diagnosing NASH.

CONCLUSIONS

Current non-invasive tests are accurate in excluding advanced fibrosis in NAFLD patients, and may be used for initial assessment. Further development and evaluation of NASH biomarkers are needed.

No significant association between vitamin D and nonalcoholic fatty liver disease in a Chinese population

BACKGROUND

Some research evidence from Western populations suggests that lower vitamin D is associated with the prevalence and histologically assessed severity of nonalcoholic fatty liver disease (NAFLD).

AIMS

To investigate the associations of serum 25-hydroxyvitamin D [25(OH)D] concentrations and vitamin D status (deficiency <20 ng/ml; insufficiency 20-30 ng/ml; sufficiency >30 ng/ml) with the prevalence of NAFLD in study population of Chinese.

METHODS

Serum 25(OH)D, parathyroid hormone, lipids, liver enzymes, and anthropometric characteristics were measured in 1,248 subjects aged ≥ 20 years. NAFLD was diagnosed using abdominal ultrasound examination.

RESULTS

The prevalence of NAFLD was 30.3 % in the total study population, 37.9 % in the male subjects, and 20.8 % in the female subjects (P < 0.0001). Subjects with NAFLD had a significantly higher body mass index, higher levels of fasting blood glucose and liver enzymes, and a more atherogenic lipid profile. However, serum 25(OH)D concentrations were not significantly different between subjects with and without NAFLD (22.1 vs. 22.8 ng/ml, respectively; P = 0.21). In addition, a 10 ng/ml higher serum 25(OH)D concentrations [odds ratio (OR) 1.02, 95 % confidence interval (CI) 0.84-1.25, P = 0.82] or vitamin D status (vs. sufficiency: deficiency OR 0.86, 95 % CI 0.54-1.37, P = 0.52; insufficiency OR 0.96, 95 % CI 0.61-1.52, P = 0.87) were not significantly associated with the presence of NAFLD in the multivariate logistic regression analyses.

CONCLUSIONS

Serum 25(OH)D concentrations or vitamin D status were not significantly associated with the presence of NAFLD. More studies are needed to elucidate the relationship between vitamin D and the occurrence of NAFLD in Chinese.

The future liver of the Asia pacific: fatter and firmer from more fructose and fortune?

The Asia Pacific region is the most diverse and the most populous region in the world. Recent socioeconomic changes have resulted in an emerging epidemic of non-communicable diseases such as type 2 diabetes and nonalcoholic fatty liver disease. The prevalence of nonalcoholic fatty liver disease in Asian Pacific countries now approximates that seen in Western countries. This increase is fueled by rising obesity, partly due to adoption of Western style diets and exposure to compounds such as high fructose corn syrup that are not included in traditional diets. Furthermore, South Asian populations may be more genetically susceptible via the inheritance of polymorphisms in apolipoprotein 3 that increase insulin resistance and nonalcoholic fatty liver disease. Importantly, there remains a substantial lack of data on the incidence and natural history of nonalcoholic steatohepatitis and subsequent complications such as hepatocellular carcinoma in Asian Pacific populations. This information gap prevents estimation of current and future disease burden and impedes efforts to lobby health policymakers to improve public health measures, as given the size of Asian Pacific populations, prevention rather than treatment of non-communicable diseases remains key. This review article addresses these issues and highlights research priorities for nonalcoholic fatty liver disease within the Asia Pacific region.

Current concepts and management approaches in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of liver dysfunction worldwide. NAFLD may progress to nonalcoholic steatohepatitis (NASH) and in turn cirrhosis. Importantly, hepatic cancer can occur in NASH in the absence of cirrhosis. The cardinal histologic feature of NAFLD is the presence of an excessive accumulation of triacylglycerols and diacylglycerols in hepatocytes. The presence of obesity and insulin resistance lead to an increased hepatic-free fatty acid (FFA) flux creating an environment appropriate for the development of NAFLD. The generation of toxic reactive oxygen species with the production of hepatic injury and inflammation as a consequence of FFA oxidation will ultimately lead to the initiation and progression of fibrosis. Lifestyle modifications specifically weight loss, physical exercise, and cognitive behavior therapy have been recommended as treatments for NASH. Dietary fructose is an independent risk factor for the development of NAFLD. Pioglitazone can be used to treat biopsy-proven NASH; however, its safety risks should be considered carefully. Greater consumption for coffee, independent of its caffeine component, has been associated with a significant reduced risk of advanced fibrosis in NASH. Additional data are needed before recommending bariatric surgery as an established option for the specific treatment of NASH.

Anthropometric measures of visceral and subcutaneous fat are important in the determination of metabolic dysregulation in boys and girls at risk for nonalcoholic fatty liver disease

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is increasing at alarming rates in obese children. The study aim was to describe body composition/somatotype and its interrelationships to biomarkers of liver disease, insulin resistance, and lipid and cytokine expression in youth with NAFLD.

METHODS

Somatotype and body composition of children (7-18 years) diagnosed with NAFLD (n= 18) were compared with obese (n = 11) and lean children (n = 17). Anthropometric variables assessed included weight, height, body mass index (BMI), waist circumference (WC), waist-to-height ratio (WHTR), and multiple skinfold thicknesses. Fat mass (FM) and somatotype analysis were measured using validated methodologies. Fasting liver biochemistries (aspartate aminotransferase [AST], alanine aminotransferase [ALT], γ-glutamyltransferase [GGT]), insulin, glucose, leptin, C-reactive protein (CRP), tumor necrosis factor-α, interleukin (IL) factors 6/10, apolipoproteins B-100/B-48 and C-III, triglycerides, and high-density lipoprotein (HDL)/low-density lipoprotein (LDL) cholesterol were measured. Insulin resistance was assessed by the homeostasis model of insulin resistance (HOMA-IR).

RESULTS

BMI z score, WC, FM, and somatotype did not differ between NAFLD and obese groups; however, lean children were lighter/leaner across all anthropometric measures (P < .001). Children with NAFLD had a higher sum-of-trunk to sum-of-extremity ratio (1.6 ± 0.4) than did obese (1.3 ± 0.2) and lean (1.1 ± 0.5) children (P < .001). Markers of central visceral (WC/WHTR) and subcutaneous fat (subscapular, abdominal, suprailiac skinfolds) were associated with elevated plasma concentrations of insulin, HOMA-IR, ALT, GGT, and AST and lower HDL cholesterol and IL-10 (P < .001).

CONCLUSION

Comprehensive assessment of body composition, including measurement of surrogate markers of subcutaneous and visceral fat, provides information regarding metabolic dysregulation and liver disease risk in obese children with NAFLD.

Real-time tissue elastography for evaluation of hepatic fibrosis and portal hypertension in nonalcoholic fatty liver diseases

The aim of this study was to prospectively measure liver stiffness with real-time tissue elastography in patients with nonalcoholic fatty liver diseases (NAFLD) and to compare the result with the clinical assessment of fibrosis using histological stage. One hundred and eighty-one prospectively enrolled patients underwent real-time tissue elastography, with the first 106 being analyzed as the training set and the remaining 75 being evaluated as the validation set. Hepatic and splenic elastic ratios were calculated and compared with stage of histological fibrosis. Portal hypertension (PH) was assessed. Real-time tissue elastography cut-off values by stage in the training set were 2.47 for F1, 2.67 for F2, 3.02 for F3, and 3.36 for F4. Using these cut-off values, the diagnostic accuracy of hepatic fibrosis in the validation set was 82.6%-96.0% in all stages. Only portal fibrosis correlated with the hepatic elastic ratio by multivariate analysis. The area under the receiver operating characteristic curve of elastic ratio better correlated than serum fibrosis markers in both early and advanced fibrosis stages. Patients with PH, defined by splenic elasticity, had early fibrosis. Patients with severe PH were found only in the group with cirrhosis.

CONCLUSION

Real-time tissue elastography is useful in evaluating hepatic fibrosis and PH in patients with NAFLD.

Non-alcoholic Fatty Liver Disease: East Versus West

Non-alcoholic fatty liver disease (NAFLD) is an important cause of liver disease worldwide with prevalence ranging from 10% to 30% in various countries. It has become an important cause of unexplained rise in transaminases, cryptogenic cirrhosis, and cryptogenic hepatocellular carcinoma. Pathogenesis is related to obesity, insulin resistance, oxidative stress, lipotoxicity, and resultant inflammation in the liver progressing to fibrosis. Pharmacological treatment in patients with NAFLD is still evolving and the treatment of these patients rests upon lifestyle modification with diet and exercise being the cornerstones of therapy. While there are many similarities between patients with NAFLD from Asia and the West, there are certain features which make the patients with NAFLD from Asia stand apart. This review highlights the data on NAFLD from Asia comparing it with the data from the West.

Systematic review: the epidemiology and natural history of non-alcoholic fatty liver disease and non-alcoholic steatohepatitis in adults

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a common cause of chronic liver disease, and its worldwide prevalence continues to increase with the growing obesity epidemic. This study assesses the epidemiology of NAFLD in adults based on clinical literature published over the past 30 years.

AIM

To review epidemiology and natural history of non-alcoholic fatty liver disease and non-alcoholic steatohepatitis in adults based on clinical literature published over the past 30 years.

METHODS

An in-depth search of PubMed (1980-2010) was based on five search terms: 'non-alcoholic fatty liver disease' OR 'non-alcoholic steatohepatitis' OR 'fatty liver' OR 'steatosis' AND 'incidence' [MeSH Terms] OR 'prevalence' [MeSH Terms] OR 'natural history'. Studies of paediatric cohorts were excluded. Articles were categorised by topic and summarised, noting generalisations concerning their content.

RESULTS

Four study categories included NAFLD incidence, prevalence, risk factors and natural history. Studies related to NAFLD prevalence and incidence indicate that the diagnosis is heterogeneous and relies on a variety of assessment tools, including liver biopsy, radiological tests such as ultrasonography, and blood testing such as liver enzymes. The prevalence of NAFLD is highest in populations with pre-existing metabolic conditions such as obesity and type II diabetes. Many studies investigating the natural history of NAFLD verify the progression from NASH to advanced fibrosis and hepatocellular carcinoma.

CONCLUSIONS

Non-alcoholic fatty liver disease is the most common cause of elevated liver enzymes. Within the NAFLD spectrum, only NASH progresses to cirrhosis and hepatocellular carcinoma. With the growing epidemic of obesity, the prevalence and impact of NAFLD continues to increase, making NASH potentially the most common cause of advanced liver disease in coming decades.

Nonalcoholic fatty liver in Asia: Firmly entrenched and rapidly gaining ground

Nonalcoholic fatty liver disease (NAFLD) is becoming an important chronic liver disorder in Asia. Prevalence figures show regional variations but at least 10% of the general population in Asia have fatty liver. Fatty liver can develop with relatively small changes in weight (2-3 kg), often with increasing central adiposity. The metabolic syndrome may precede or follow NAFLD. Overt diabetes is present in one-third of cases but when oral glucose tolerance tests are performed, a further third of individuals have impaired glucose tolerance or diabetes. Natural history data are still scarce but cases of advanced hepatic fibrosis and hepatocellular carcinoma are now regularly reported. Many cases of cryptogenic cirrhosis are also attributable to NAFLD. Histological progression has been demonstrated for patients with NASH as well as for those with hepatic steatosis alone. Genetic factors may in part contribute to the rise in NAFLD. Polymorphisms within apolipoprotein C3 (APOC3) gene have been linked to NAFLD in lean Indian men. Although a number of other polymorphisms involving genes controlling adipose distribution, insulin signalling, adipokine responses and hepatic fibrosis have been reported, these studies have been underpowered. Transient elastography could help in detecting and monitoring hepatic fibrosis but further refinements in technique are necessary for obese individuals. Of the biomarkers, hyaluronic acid and cytokeratin-18 fragment testing show promise as markers of hepatic fibrosis and NASH, respectively. Lifestyle alterations including dietary changes and increased physical activity remain the cornerstone of management. Attention should be paid to prevention through public education of campaigns addressing the increase in both adult and childhood obesity.

Diagnosis of fibrosis and cirrhosis using liver stiffness measurement in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is one of the most common liver diseases in affluent countries. Accurate noninvasive tests for liver injury are urgently needed. The aim of this study was to evaluate the accuracy of transient elastography for the diagnosis of fibrosis and cirrhosis in patients with NAFLD and to study factors associated with discordance between transient elastography and histology. Two hundred forty-six consecutive patients from two ethnic groups had successful liver stiffness measurement and satisfactory liver biopsy specimens. The area under the receiver-operating characteristics curve (AUROC) of transient elastography for F3 or higher and F4 disease was 0.93 and 0.95, respectively, and was significantly higher than that of the aspartate aminotransferase-to-alanine aminotransferase ratio, aspartate aminotransferase-to-platelet ratio index, FIB-4, BARD, and NAFLD fibrosis scores (AUROC ranged from 0.62 to 0.81, P < 0.05 for all comparisons). At a cutoff value of 7.9 kPa, the sensitivity, specificity, and positive and negative predictive values for F3 or greater disease were 91%, 75%, 52%, and 97%, respectively. Liver stiffness was not affected by hepatic steatosis, necroinflammation, or body mass index. Discordance of at least two stages between transient elastography and histology was observed in 33 (13.4%) patients. By multivariate analysis, liver biopsy length less than 20 mm and F0-2 disease were associated with discordance.

CONCLUSION

Transient elastography is accurate in most NAFLD patients. Unsatisfactory liver biopsy specimens rather than transient elastography technique account for most cases of discordance. With high negative predictive value and modest positive predictive value, transient elastography is useful as a screening test to exclude advanced fibrosis. Liver biopsy may be considered in NAFLD patients with liver stiffness of at least 7.9 kPa.

Epidemiology and natural history of non-alcoholic steatohepatitis

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver condition in many parts of the world. This article describes the epidemiology and natural history of this disorder. It also describes current diagnostic and treatment methods and describes future implications NAFLD may have.

Non-alcoholic fatty liver disease: an expanding problem with low levels of awareness in Hong Kong

BACKGROUND AND AIM

With the Westernization of the lifestyle and the rising prevalence of obesity and diabetes mellitus, non-alcoholic fatty liver disease (NAFLD) is an emerging health problem in the Asia-Pacific region. The purpose of this study was to determine the awareness of NAFLD among the general population in Hong Kong.

METHODS

A random telephone survey was conducted from September 2007 to January 2008 using a structured multiple-choice questionnaire. Subjects were Hong Kong residents aged 18 or above who spoke Cantonese.

RESULTS

In the first phase of the telephone survey, 521 subjects were interviewed and the results showed that as high as 83% of respondents had never come across the term 'NAFLD'. Upon completion of the second phase telephone survey, a total of 508 respondents who had heard of NAFLD were successfully interviewed. Of the 508 respondents, nearly half of them (42%) expressed no idea about the prevalence of NAFLD in Hong Kong. About half of respondents (47%) knew nothing about the clinical presentation of NAFLD. The majority of them (78%) had a misconception that blood tests could provide a definite diagnosis of NAFLD. Smoking, hepatitis B carriage and a past history of hepatitis A infection were cited as risk factors of NAFLD by 52%, 57% and 42% of respondents, respectively. Of the 508 respondents who had heard of NAFLD, most of them perceived that their knowledge of NAFLD was either inadequate (46%) or highly inadequate (35%).

CONCLUSION

This survey revealed an inadequate knowledge of NAFLD among the general population in Hong Kong.

Systematic review of risk factors for fibrosis progression in non-alcoholic steatohepatitis

BACKGROUND/AIMS

Non-alcoholic steatohepatitis (NASH) is a growing public health problem. Evaluation of risk factors for fibrosis in NASH will help to target resources to reduce development of cirrhosis. This study had two aims; the first to compile longitudinal histological data to characterize the natural history of fibrosis progression in NASH, and second, to identify predictive factors for progression to advanced fibrosis (stage 3 or greater) in NASH.

METHODS

Subjects had to have a histological diagnosis compatible with NASH on their initial biopsy, received no intervention of proven histological benefit, and undergone two liver biopsies with at least an interval of one year between them.

RESULTS

Ten studies were selected comprising 221 patients. 37.6% had progressive fibrosis over a mean follow-up interval of 5.3 years (SD, 4.2 years, median, 3.7 years, range 1.0-21.3 years). Proportional hazards regression analysis demonstrated that age (HR=0.98, p=0.009) and inflammation on initial biopsy (any inflammation, HR=2.5, p=0.001; grade 1, HR=2.5, p=0.001; grade 2, HR=2.4, p=0.003) are independent predictors of progression to advanced fibrosis. Other traditional parameters (e.g. obesity, diabetes, hypertension) were not statistically significant predictors.

CONCLUSIONS

Presence of inflammation on the initial biopsy and age are independent predictors of progression to advanced fibrosis in patients with NASH.

Effect of body weight and lifestyle changes on long-term course of nonalcoholic fatty liver disease in Koreans

BACKGROUND

Although the prevalence of nonalcoholic fatty liver disease (NAFLD) has been increasing, there have been few studies of long-term changes in NAFLD in large numbers of subjects. This study was performed to assess the long-term changes in severity of fatty liver and to analyze the association with changes in body weight and lifestyle factors.

METHODS

We analyzed lifestyle factors, biochemical data, and abdominal ultrasonography in subjects who underwent voluntary medical checkups at a 5-year interval. Fatty liver on ultrasonography was graded as normal, mild, moderate, or severe by the degree of echogenicity.

RESULTS

The analyzed population consisted of 2895 subjects of age 47+/-8.7 years (range, 20-79 years). Among the 1938 subjects who had normal livers at baseline, 374 subjects (19%) developed fatty liver 5 years later. Those who developed fatty liver showed more weight gain, increase of aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma glutamyl transferase (gamma-GT), and glucose levels during the 5-year period. Among the 930 subjects who had fatty liver at baseline, 263 (28%) subjects showed a decrease in grade and 209 (22%) progressed to a higher grade of fatty liver after 5 years. The group with a lower grade lost -2.2+/-4.3 kg of body weight from baseline, and reduction in hepatic steatosis grade was associated with decreased serum AST, ALT, triglycerides, gamma-GT, and fasting glucose levels.

CONCLUSIONS

Even a small weight reduction was associated with improvements in NAFLD and related metabolic abnormalities such as dyslipidemia and hyperglycemia. Subjects with fatty liver should be advised to lose weight through lifestyle modifications.

Metabolic and histological features of non-alcoholic fatty liver disease patients with different serum alanine aminotransferase levels

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in affluent countries. Serum alanine aminotransferase (ALT) level is commonly performed to monitor NAFLD patients, but its clinical relevance is unclear.

AIM

To evaluate the metabolic and histological features of NAFLD patients with different ALT levels.

METHODS

A total of 173 consecutive patients with biopsy-proven NAFLD were studied. Patients with persistently normal ALT and those with abnormal ALT were compared.

RESULTS

Patients with persistently normal ALT had lower steatosis grade than patients with abnormal ALT, but they had similar degree of lobular inflammation, ballooning and fibrosis. Among 19 patients with ALT below 0.5 times the upper limit of normal (ULN) at the time of liver biopsies, 8 (42%) and 3 (16%) had steatohepatitis and significant fibrosis respectively. The within-patient coefficient of variance was similarly high in patients with simple steatosis and steatohepatitis (33.5). Age and glucose, but not ALT, were independent factors associated with significant fibrosis.

DISCUSSION

Metabolic factors, but not ALT, are associated with histological severity. Patients with ALT < 0.5 x ULN may still have non-alcoholic steatohepatitis (NASH) and significant fibrosis. Evaluation of NAFLD patients should be based on metabolic risk factors, but not ALT level.

Epidemiology of non-alcoholic fatty liver disease in China

Fatty liver (steatosis) is highly prevalent in China and is more often linked to obesity than to alcoholism. Among more affluent regions of China, the community prevalence of non-alcoholic fatty liver disease (NAFLD) is approximately 15%. With the increasing pandemic of obesity, the prevalence of NAFLD has approximately doubled in the past decade. The risk factors resemble those in other ethnic populations, but it is important to note that ethnic-specific definitions of central obesity, obesity and metabolic syndrome are more useful in assessment of Chinese people. The full range of histological manifestations of NAFLD has been demonstrated in Chinese patients, but to date hepatic severity is generally mild. In contrast to chronic hepatitis C, steatosis is less common in patients with chronic hepatitis B; it is associated with metabolic, and not viral factors and does not appear to affect disease severity. Although long-term outcomes of NAFLD in Chinese populations remain unclear, it may be a predictor of metabolic disorders, diabetes and cardiovascular disease. Public health interventions are therefore indicated to halt or reverse the national trend of obesity in China so as to improve liver as well as metabolic health.

Disease-specific mechanisms of fibrosis: hepatitis C virus and nonalcoholic steatohepatitis

Our mechanistic understanding of liver fibrosis has increased dramatically in recent years for all liver diseases and for hepatitis C and nonalcoholic steatohepatitis (NASH) in particular. Hepatitis C causes liver injury and fibrosis through direct cytopathic means, direct and indirect interactions with hepatic stellate cells, and activation of the immune system. Steatosis and insulin resistance, which are intrinsic deficits in NASH, are also of great importance in hepatitis C and may be induced by viral or host metabolic factors. For NASH, the key mediators of damage include oxidative stress, fat compartmentalization, visceral fat, apoptosis, and adipokine derangement. This article explores in depth the disease-specific mechanisms of fibrosis in hepatitis C and NASH, with a focus on recent developments.

Assessment of fibrosis by transient elastography compared with liver biopsy and morphometry in chronic liver diseases

BACKGROUND & AIMS

Liver stiffness measurement (LSM) with transient elastography (Fibroscan) can accurately diagnose advanced liver fibrosis, but its performance in early liver fibrosis is less satisfactory. We aimed to study the diagnostic performance of LSM for histologic bridging fibrosis and cirrhosis in various chronic liver diseases and to investigate the effects of liver fibrosis distribution on LSM.

METHODS

We prospectively studied consecutive patients with chronic liver diseases undergoing liver biopsy and transient elastography examinations. Morphometric analysis was performed to evaluate the distribution of liver fibrosis.

RESULTS

One hundred thirty-three patients (50% chronic hepatitis B, 14% chronic hepatitis C, and 24% nonalcoholic fatty liver disease) were studied. Morphometric analysis revealed a higher correlation between LSM and pericellular fibrosis (r = 0.43) than periportal (r = 0.21) or perivenular fibrosis (r = 0.25). Area under receiver operating characteristic curve (ROC) of LSM for bridging fibrosis was 0.87 (95% confidence interval, 0.81-0.93) and for cirrhosis was 0.89 (95% confidence interval, 0.83-0.94). Higher LSM was associated with higher serum ALT level. Patients with the same fibrosis staging but higher ALT levels tend to have higher LSM. The area under ROC curve of LSM for cirrhosis was lower among patients who had ALT above the upper limit of normal (0.86) as compared with that of patients with normal ALT levels (0.93, P = .03).

CONCLUSIONS

Transient elastography can diagnose severe fibrosis because of its good correlation with pericellular fibrosis. Transient elastography might overestimate liver fibrosis when ALT is elevated.

Validation of the NAFLD fibrosis score in a Chinese population with low prevalence of advanced fibrosis

OBJECTIVES

Nonalcoholic fatty liver disease (NAFLD) is increasing in prevalence worldwide. This study aimed to validate the NAFLD fibrosis score in the Chinese population.

METHODS

NAFLD patients were prospectively recruited for liver biopsy and blood tests. The NAFLD fibrosis score was calculated as -1.675 + 0.037 x age (yr) + 0.094 x BMI (kg/m(2)) + 1.13 x impaired fasting glucose/diabetes (yes = 1, no = 0) + 0.99 x AST/ALT ratio-0.013 x platelet (x10(9)/L)-0.66 x albumin (g/dL). Advanced fibrosis was defined as stage 3 to 4 fibrosis.

RESULTS

One hundred sixty-two patients (age 46 +/- 10 yr, male 59%) were included in the study. Advanced fibrosis was found in 18 (11%) patients. Only 11 of 128 patients with the NAFLD fibrosis score below the proposed low cutoff point (<-1.455) were under-staged, resulting in a high negative predictive value of 91%. Only two patients exceeded the proposed high cutoff point (>0.676), but neither had advanced fibrosis. If the NAFLD fibrosis score was implemented in the Chinese population, 79% of liver biopsies could be avoided.

CONCLUSIONS

The NAFLD fibrosis score has high negative predictive value in excluding advanced fibrosis in the Chinese population, and can reduce the burden of liver biopsy in the vast majority of cases. Since there were few cases of advanced fibrosis in this cohort, this study had limited power in validating the high cutoff point.