Prevalence of non-alcoholic fatty liver disease and risk factors for advanced fibrosis and mortality in the United States

Clinical relevance of liver histopathology and different histological classifications of NASH in adults

Nonalcoholic fatty liver disease (NAFLD) encompasses simple steatosis and steatohepatitis (NASH) with or without fibrosis/cirrhosis and hepatocellular carcinoma. NAFLD occurs epidemically in most areas of the world, contributes to cardiovascular events and liver-related mortality and therefore exacts a major economic toll. Areas covered: Here we summarize what clinicians should know about NAFLD histopathology in adults. We report on the individual histological features and scoring systems of NAFLD: the NAFLD activity score (NAS) introduced by the NASH-Clinical Research Network, the 'Fatty Liver Inhibition of Progression' algorithm and Steatosis, Activity, and Fibrosis (SAF) score. Pros and cons of histological classifications in NASH are discussed. Special emphasis is given to liver histopathology in some high-risk patient groups, such as those with severe obesity and type 2 diabetes. Moreover, we also examine the relationship between liver histopathology and clinical features, and the impact of liver histopathology on the long-term prognosis of NAFLD. Finally, we propose an integrated diagnostic approach which utilizes both non-invasive tools and liver biopsy in those individual patients with suspected NAFLD. Expert commentary: Based on expert opinions, we conclude with a research agenda on NAFLD which focuses on the most burning topics to be addressed over the next five years.

Non-alcoholic steatofibrosis (NASF) can independently predict mortality in patients with non-alcoholic fatty liver disease (NAFLD)

Background

Hepatic fibrosis in patients with non-alcoholic fatty liver disease (NAFLD) independently predicts mortality. Given liver biopsy’s invasive nature, non-invasive method to assess hepatic steatosis and fibrosis provides NAFLD risk stratification algorithm in clinical practice. NAFLD fibrosis score (NFS) is simple and non-invasive predictive model recommended by American Association for the Study of Liver Disease (AASLD) Guideline to identify patients with NAFLD with fibrosis risk. The aim of this study is to assess long-term outcomes of subjects with significant non-alcoholic steatofibrosis (NASF) as established by ultrasound (US) and NFS.

Methods

Used National Health and Nutrition Examination Survey (NHANES III) with National Death Index-linked Mortality Files. NAFLD diagnosis established by the presence of moderate to severe hepatic steatosis on US without other causes of chronic liver disease (alcohol consumption <20 gr/day, hepatitis B surface-antigen negative, anti-hepatitis C virus antibody negative, transferrin saturation <50%). Significant hepatic fibrosis was estimated by high NFS (>0.676) and calculated with previously published formula. Subjects with NAFLD and high NFS have significant NASF.

Results

NHANES III included 20 050 adult participants. 2515 participants complete data and NAFLD with 5.1% (n=129) meeting criteria for significant SF. Subjects with significant SF were older, had higher body mass index, waist circumference and the homeostasis model assessment (HOMA) scores and higher rates of comorbidities (diabetes, congestive heart failure (CHF), stroke; all p<0.001). After median of 207 months of follow-up, overall mortality in NAFLD cohort was 30.0% (n=754). Crude mortality higher in subjects with significant SF (67.4% vs 28.0%, p<0.001). In multivariate survival analysis, predictors of overall mortality included significant SF (adjusted HR (aHR): 1.37; 95% CI 1.07 to 1.76, p=0.01), older age (aHR:1.08; 95% CI 1.07 to 1.09 per year), male gender (aHR:1.44; 95% CI 1.24 to 1.67), black race (aHR:1.24; 95% CI 1.04 to 1.48)), history of hypertension (aHR:1.40; 95% CI 1.20 to 1.64), diabetes (aHR:1.69; 95% CI 1.43 to 2.00), CHF (aHR:1.77; 95% CI 1.38 to 2.261), stroke (aHR:1.84; 95% CI 1.38 to 2.48) and smoking (aHR:1.74; 95% CI 1.47 to 2.07) (all p<0.02). Sensitivity analysis showed that the best association of SF with mortality is higher at NFS threshold of 0.80 (aHR:1.41; 95% CI 1.09 to 1.83, p=0.01).

Conclusions

Significant NASF determined non-invasively is an independent predictor of mortality. These data should help clinicians to easily risk-stratify patients with NAFLD for close monitoring and treatment considerations in clinical trial setting.

Increasing co-morbidities in chronic hepatitis B patients: experience in primary care and referral practices during 2000-2015

OBJECTIVES

Data on liver and non-liver co-morbidities in chronic hepatitis B (CHB) patients are limited. This study analyzes the prevalence of co-morbidities in a multicenter CHB cohort evaluated over 15 years.

METHODS

This study included 2734 consecutive adult American CHB patients from a university medical center and several community primary care clinics. Data were analyzed by time periods (patients in each time period were unique without overlapping): 2000-2005 (n = 885), 2006-2010 (n = 888), and 2011-2015 (n = 961). Patients were identified via electronic query using diagnosis code with data confirmed and extracted via individual chart review. Most patients were male (57.9%) and Asian (89.6%).

RESULTS

Mean age increased significantly from 43.3 ± 13.4 years during 2000-2005 to 49.1 ± 14.4 during 2011-2015 (p < 0.001). Between 2000-2005 and 2011-2015, fatty liver disease among new CHB patients increased from 1.6 to 6.8% (p < 0.001). Advanced liver diseases also increased (p < 0.001): cirrhosis (12.6-24.6%), hepatic decompensation (1.1-7.9%), and hepatocellular carcinoma (HCC) (4.9-9.1%). Similar trends were observed for non-liver co-morbidities (p < 0.001). Specifically, diabetes increased almost fivefold (4.9-22.9%), hypertension increased threefold (12.3-36.1%) and chronic kidney disease increased 4.5-fold (4.4-19.7%). Prevalence of osteopenia and osteoporosis also increased in CHB patients: 5.4-13.4% (p < 0.001) and 2.9-8.7% (p < 0.001), respectively. These trends were observed in both liver clinics and primary care clinics (except for advanced liver disease), treated and untreated patients, and for both sexes.

CONCLUSIONS

The CHB patient population is aging and now presents with significantly more co-morbidities. Early diagnosis and linkage to care is needed to prevent and mitigate liver as well as non-liver co-morbidities.

Altered global microRNA expression in hepatic stellate cells LX-2 by angiotensin-(1-7) and miRNA-1914-5p identification as regulator of pro-fibrogenic elements and lipid metabolism

The development of new therapeutic strategies to control or reverse hepatic fibrosis requires thorough knowledge about its molecular and cellular basis. It is known that the heptapeptide angiotensin-(1-7) [ang-(1-7)] can reduce hepatic fibrosis and steatosis in vivo; therefore, it is important to uncover the mechanisms regulating its activity and cellular model of investigation. Ang-(1-7) is a peptide of the renin-angiotensin system (RAS), and here we investigated its modulatory effect on the expression pattern of microRNAs (miRNAs) in hepatic stellate cells (HSCs) LX-2, which transdifferentiate into fibrogenic and proliferative cells. We compared the miRNA profiles between quiesced, activated and ang-(1-7)-treated activated HSCs to identify miRNAs that may regulate their transdifferentiation. Thirteen miRNAs were pointed, and cellular and molecular analyses identified miRNA-1914-5p as a molecule that contributes to the effects of ang-(1-7) on lipid metabolism and on the pro-fibrotic environment control. In our cellular model, we also analyzed the regulators of fatty acid metabolism. Specifically, miRNA-1914-5p regulates the expression of malonyl-CoA decarboxylase (MLYCD) and phosphatidic acid phosphohydrolase (PAP or Lipin-1). Additionally, Lipin-1 was closely correlated with mRNA expression of peroxisome proliferator-activated receptors (PPAR)-α and -γ, which also contribute to lipid homeostasis and to the reduction of TGF-β1 expression. These findings provide a novel link between RAS and lipid metabolism in controlling HSCs activation.

Arsenic exposure and risk of nonalcoholic fatty liver disease (NAFLD) among U.S. adolescents and adults: an association modified by race/ethnicity, NHANES 2005-2014

BACKGROUND

While associated with obesity, the cause of the rapid rise in prevalence of nonalcoholic fatty liver disease (NAFLD) in children, which is highest among Hispanics, is not well understood. Animal experiments have demonstrated that arsenic exposure contributes to liver injury. Our objective was to examine the association between arsenic exposure and NAFLD in humans and to determine if race/ethnicity modifies the association.

METHODS

Urinary inorganic arsenic concentrations among those ≥12 years in the National Health and Nutrition Examination Survey, 2005-2014 were used to assess the cross-sectional association with serum alanine aminotransferase (ALT) levels, a marker of liver dysfunction. We excluded high alcohol consumers (>4-5 drinks/day; n = 939), positive hepatitis B or C (n = 2330), those missing body mass index (n = 100) and pregnant women (n = 629) for a final sample of 8518. Arsenic was measured using liquid chromatography coupled with mass spectrometry and ALT was measured using standard methods. Sampling weights were used to obtain national estimates. Due to lack of normality, estimates were log transformed and are presented as geometric means. Logistic regression models controlling for age, sex, income, and weight category estimate adjusted odd ratios (aOR) of elevated ALT by quartile of arsenic and tested for effect modification by race/ethnicity and weight. Elevated ALT was defined as >25 IU/L and >22 IU/L for boys and girls ≤17 years, respectively and >30 IU/L and >19 IU/L for men and women, respectively.

RESULTS

Among all, aOR of elevated ALT were higher among those in the highest vs. lowest arsenic quartile (referent), 1.4 (95% confidence interval [CI]: 1.1, 1.7) with a borderline significant interaction (p = 0.07) by race/ethnicity but not weight (p = 0.4). In analysis stratified by race/ethnicity, aOR of elevated ALT among those in the 4th quartile were higher among Mexican Americans, 2.0 (CI: 1.3, 3.1) and non-Hispanic whites only, aOR 1.4 (CI: 1.1, 1.8) despite the fact that obesity prevalence was highest among non-Hispanic blacks.

CONCLUSIONS

Our findings demonstrate a positive association between urinary arsenic exposure and risk of NAFLD among U.S. adolescents and adults that is highest among Mexican Americans and among those obese, regardless of race/ethnicity.

Endocrine Disruptors and Developmental Origins of Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is a growing epidemic worldwide, particularly in countries that consume a Western diet, and can lead to life-threatening conditions such as cirrhosis and hepatocellular carcinoma. With increasing prevalence of NAFLD in both children and adults, an understanding of the factors that promote NAFLD development and progression is crucial. Environmental agents, including endocrine-disrupting chemicals (EDCs), which have been linked to other diseases, may play a role in NAFLD development. Increasing evidence supports a developmental origin of liver disease, and early-life exposure to EDCs could represent one risk factor for the development of NAFLD later in life. Rodent studies provide the strongest evidence for this link, but further studies are needed to define whether there is a causal link between early-life EDC exposure and NAFLD development in humans. Elucidating the molecular mechanisms underlying development of NAFLD in the context of developmental EDC exposures may identify biomarkers for people at risk, as well as potential intervention and/or therapeutic opportunities for the disease.

Risk factors for biopsy-proven advanced non-alcoholic fatty liver disease in the Veterans Health Administration

BACKGROUND

With its increasing incidence, nonalcoholic fatty liver disease (NAFLD) is of particular concern in the Veterans Health Administration (VHA).

AIMS

To evaluate risk factors for advanced fibrosis in biopsy-proven NAFLD in the VHA, to identify patients at risk for adverse outcomes.

METHODS

In randomly selected cases from VHA databases (2005-2015), we performed a retrospective case-control study in adults with biopsy-defined NAFLD or normal liver.

RESULTS

Of 2091 patients reviewed, 399 met inclusion criteria. Normal controls (n = 65) had normal liver function. The four NAFLD cohorts included: NAFL steatosis (n = 76), nonalcoholic steatohepatitis (NASH) without fibrosis (n = 68), NAFLD/NASH stage 1-3 fibrosis (n = 82), and NAFLD/NASH cirrhosis (n = 70). NAFLD with hepatocellular carcinoma (HCC) was separately identified (n = 38). Most patients were older White men. NAFLD patients with any fibrosis were on average severely obese (BMI>35 kg/m² ). Diabetes (54.4%-79.6%) and hypertension (85.8%-100%) were more common in NAFLD with fibrosis or HCC. Across NAFLD, 12.3%-19.5% were enrolled in diet/exercise programs and 0%-2.6% had bariatric surgery. Hispanics exhibited higher rates of NASH (20.6%), while Blacks had low NAFLD rates (1.4%-11.8%), particularly NAFLD cirrhosis and HCC (1.4%-2.6%). Diabetes (OR 11.8, P < .001) and BMI (OR 1.4, P < .001) were the most significant predictors of advanced fibrosis.

CONCLUSIONS

In the VHA, diabetes and severe obesity increased risk for advanced fibrosis in NAFLD. Of these patients, only a small proportion (~20%) had enrolled in diet/exercise programs or had bariatric surgery (~2%). These results suggest that providers should focus/tailor interventions to improve outcomes, particularly in those with diabetes and severe obesity.

The Challenges of Nutritional Assessment in Cirrhosis

Purpose of Review

Nutritional status in patients with cirrhosis is very frequently associated with macro- and micronutrient deficiencies. Cirrhosis itself is the cause of malnutrition and nutritional deficiencies but these conditions have to be identified and addressed properly as they can worsen the prognosis of cirrhosis. The goals of this review are to 1) identify and describe the challenges associated with nutritional assessment in cirrhosis and 2) describe recent advancements when using clinical, laboratory, and instrumental tools in the evaluation of malnourished patients with liver diseases.

Recent Findings

The most promising tools for nutritional assessment in cirrhosis include the evaluation of body composition with phase angle obtained by bioelectrical impedance analysis, computed tomography transverse images at the level of third lumbar vertebra. The Royal-Free Hospital global assessment algorithm appears to be helpful but needs further validation.

Summary

Nutritional assessment in cirrhosis is challenging as several factors, including edema, can interfere with it and because of lack of a validated gold standard. Regardless, nutritional assessment methods have been developed in recent years and should gain relevance in the clinical practice.