Lean Americans With Nonalcoholic Fatty Liver Disease Have Lower Rates of Cirrhosis and Comorbid Diseases

Post-hoc analysis of the tofogliflozin post-marketing surveillance study (J-STEP/LT): Tofogliflozin improves liver function in type 2 diabetes patients regardless of BMI

AIMS/INTRODUCTION

Patients with type 2 diabetes are at high risk of developing steatotic liver disease (SLD). Weight loss has proven effective in treating metabolic dysfunction-associated steatotic liver disease (MASLD) in obese patients with type 2 diabetes, with sodium-glucose cotransporter 2 (SGLT2) inhibitors showing promising results. However, lean MASLD is more prevalent in Japan, necessitating alternative approaches to body weight reduction.

MATERIALS AND METHODS

We used the J-STEP/LT dataset including up to 3-year treatment data to analyze the effects of the SGLT2 inhibitor tofogliflozin on liver function and treatment safety and conducted a subgroup analysis based on body mass index (BMI; kg/m2, <20, 20-<23, 23-<25, 25-<30, and ≥30).

RESULTS

This study included 4,208 participants. Tofogliflozin significantly reduced alanine aminotransferase (ALT) levels in participants with baseline ALT levels >30 U/L across all BMI groups, with median changes of -12, -16, -13, -15, and -15 U/L, respectively (P = 0.9291 for trends). However, median changes in body weight with tofogliflozin were -2.00, -2.75, -2.00, -3.00, and -3.80 kg, respectively (P < 0.0001 for trends), with no significant weight loss observed in the BMI <20 group. ALT levels were also significantly decreased in participants who did not lose weight. Safety assessments according to BMI and age categories revealed no clear differences in the frequency of adverse events.

CONCLUSIONS

Tofogliflozin reduced ALT levels without substantial body weight reduction among lean participants. These findings suggest that SGLT2 inhibitors may be a viable treatment option for non-obese patients with type 2 diabetes and SLD.

Heterogeneity of cardiometabolic and hepatic fibrosis risks in nonalcoholic fatty liver disease among lean, overweight, and obese populations: a multicenter cross-sectional study

OBJECTIVE

Given that cardiovascular events induced by metabolic disorders are the leading cause of death in nonalcoholic fatty liver disease (NAFLD), this study aimed to explore the heterogeneity of cardiometabolic and liver fibrosis risks among lean, overweight, and obese NAFLD individuals.

METHODS

A multicenter cross-sectional study was conducted across three hospitals in Pudong from July 2022 to June 2023. Health checkup data were obtained and stratified by BMI categories. Multivariable logistic regression was performed to analyze the association between NAFLD and risk factors for cardiometabolic diseases and liver fibrosis across different BMI categories.

RESULTS

The study included 37,122 patients, with 25.25% diagnosed with NAFLD. Over 97% of these patients met the criteria for metabolic dysfunction-associated fatty liver disease. NAFLD detection rates were 7.72% in lean, 33.99% in overweight, and 63.56% in obese individuals. Non-obese patients had significantly lower cardiometabolic disease prevalence than obese patients (P < 0.001). All NAFLD subtypes, except lean NAFLD (negatively associated with total cholesterol) and obese NAFLD (no significant association with total triglycerides), were linked to other cardiometabolic or liver fibrosis risk factors (P < 0.05). Additioinally, only obese NAFLD demonstrated a negative correlation with age.

CONCLUSION

Non-obese NAFLD, despite a relatively better metabolic profile than obese NAFLD, still poses significant cardiometabolic and fibrosis risks. Interventions targeting cardiovascular events and liver disease progression are essential for all NAFLD subtypes, customized to their metabolic characteristics. The detection rates in this study provide a valuable reference for estimating local NAFLD prevalence.

Association between prognostic nutritional index and all-cause mortality and cardiovascular disease mortality in American adults with non-alcoholic fatty liver disease

Background

The current research was to investigate the relationship between prognostic nutritional index (PNI) and mortality, with a focus on all-cause and cardiovascular disease (CVD) mortality, for those with non-alcoholic fatty liver disease (NAFLD).

Methods

Data from 20,142 patients who participated in the National Health and Nutrition Examination Survey (NHANES), which was carried out between 2005 and 2014, were included in this research. To examine the relationship between PNI and both all-cause and cardiovascular mortality, we employed weighted Cox regression models with multiple variables. Kaplan-Meier survival curves were utilized to visualize the survival distribution across different levels of PNI. The non-linear association between PNI and mortality was addressed through penalized spline smoothing. Subgroup analyses were conducted to examine the potential influence of relevant clinical variables on the relationship between PNI and mortality. The precision of PNI in forecasting the outcome of survival was assessed as well using time-dependent receiver operating characteristic curve (ROC) analysis.

Results

Kaplan-Meier analysis linked higher PNI to significantly reduced all-cause and CVD mortality. Multivariable Cox models demonstrated that increasing PNI consistently lowered mortality risks. With a threshold value of 50.5, the link between PNI and mortality showed a non-linear pattern after adjusting for confounding factors. Subgroup analyses confirmed robust associations, particularly in race, education, BMI, and fibrosis. Time-dependent ROC analysis highlighted the strong predictive performance of PNI across various time points.

Conclusion

PNI played a significant role as an effective predictor of prognosis in individuals diagnosed with NAFLD.

Diabetes as a risk factor for MASH progression

Non-alcoholic (now: metabolic) steatohepatitis (MASH) is the progressive inflammatory form of metabolic dysfunction-associated steatotic liver disease (MASLD), which often coexists and mutually interacts with type 2 diabetes (T2D), resulting in worse hepatic and cardiovascular outcomes. Understanding the intricate mechanisms of diabetes-related MASH progression is crucial for effective therapeutic strategies. This review delineates the multifaceted pathways involved in this interplay and explores potential therapeutic implications. The synergy between adipose tissue, gut microbiota, and hepatic alterations plays a pivotal role in disease progression. Adipose tissue dysfunction, particularly in the visceral depot, coupled with dysbiosis in the gut microbiota, exacerbates hepatic injury and insulin resistance. Hepatic lipid accumulation, oxidative stress, and endoplasmic reticulum stress further potentiate inflammation and fibrosis, contributing to disease severity. Dietary modification with weight reduction and exercise prove crucial in managing T2D-related MASH. Additionally, various well-known but also novel anti-hyperglycemic medications exhibit potential in reducing liver lipid content and, in some cases, improving MASH histology. Therapies targeting incretin receptors show promise in managing T2D-related MASH, while thyroid hormone receptor-β agonism has proven effective as a treatment of MASH and fibrosis.

Characteristics of intestinal flora in nonobese nonalcoholic fatty liver disease patients and the impact of ursodeoxycholic acid treatment on these features

The study aimed to investigate the alterations in gut microbiota among nonobese individuals with nonalcoholic fatty liver disease (NAFLD) and their response to treatment with ursodeoxycholic acid (UDCA). A total of 90 patients diagnosed with NAFLD and 36 healthy subjects were recruited to participate in this study. Among them, a subgroup of 14 nonobese nonalcoholic steatohepatitis (NASH) were treated with UDCA. Demographic and serologic data were collected for all participants, while stool samples were obtained for fecal microbiome analysis using 16S sequencing. In nonobese NAFLD patients, the alpha diversity of intestinal flora decreased (Shannon index, p < 0.05), and the composition of intestinal flora changed (beta diversity, p < 0.05). The abundance of 20 genera, including Fusobacterium, Lachnoclostridium, Klebsiella, etc., exhibited significant changes (p < 0.05). Among them, nine species including Fusobacterium, Lachnoclostridium, Klebsiella, etc. were found to be associated with abnormal liver enzymes and glucolipid metabolic disorders. Among the 14 NASH patients treated with UDCA, improvements were observed in terms of liver enzymes, CAP values, and E values (p < 0.05), however, no improve the glucolipid metabolism. While the alpha diversity of intestinal flora did not show significant changes after UDCA treatment, there was a notable alteration in the composition of intestinal flora (beta diversity, p < 0.05). Furthermore, UCDA treatment led to an improvement in the relative abundance of Alistipes, Holdemanella, Gilisia, etc. among nonobese NASH patients (p < 0.05). Nonobese NAFLD patients exhibit dysbiosis of the intestinal microbiota. UDCA can ameliorate hepatic enzyme abnormalities and reduce liver fat content in nonobese NASH patients, potentially through its ability to restore intestinal microbiota balance.

Interaction between non-alcoholic fatty liver disease and obesity on the risk of developing cardiovascular diseases

BACKGROUNDS

This investigation seeks to explore the correlation between nonalcoholic fatty liver disease (NAFLD) and cardiovascular diseases (CVDs), and to to provide evidence for the prevention and treatment of CVDs.

METHODS

This study utilized data from the Jinchang cohort platform, including 19,399 participants without pre-existing major CVDs. Based on the general population and gender stratification, Cox models were used to analyze the risk of NAFLD for CVDs. The combined effect of NAFLD and different obesity indicators on CVDs was analyzed by additive and multiplicative interaction models and subgroups.

RESULTS

There were 3129 NAFLD patients out of 19399 subjects, and 723 (23.11%) of them had the CVD. After adjusting for multiple confounding factors, the Cox model revealed a 1.17-fold increase in the risk of CVDs among patients with NAFLD compared to those without NAFLD. Moreover, there was no notable disparity in CVDs risk among most NAFLD patients at the same level of obesity. The results indicated no additive interaction between NAFLD and obesity concerning CVDs risk, but rather a positive multiplicative interaction. Using the normal population as a reference, it was found that people with both obesity and NAFLD significantly increased the risk of developing CVDs, with HRs and 95% CIs of 1.790 (1.508, 2.126), 1.356 (1.213, 1.517), and 1.807 (1.503, 2.174), respectively, for BMI, WC, and the combination of BMI and WC.

CONCLUSIONS

NAFLD and obesity are independent risk factors for CVDs. The synergy of obesity and NAFLD implies that NAFLD patients should control weight gain. Larger BMI and WC values may increase the CVDs risk for NAFLD patients, especially women.

Characterizing Nonalcoholic Fatty Liver Disease (NAFLD) in Lean Individuals at a Tertiary Care Hospital: A Cross-sectional Study

Background

Fat accumulation in the liver is affecting 38% of the global population. It can also occur in normal-weight individuals, termed lean non-alcoholic fatty liver disease (NAFLD). This study examines Asian and Western body mass index (BMI) criteria, as well as metabolic dysfunction-associated fatty liver disease (MAFLD) and metabolic dysfunction-associated steatotic liver disease (MASLD) diagnostic guidelines, in lean fatty liver cases within a healthcare setting.

Materials and methods

This study was cross-sectional included 111 lean patients diagnosed with NAFLD using either ultrasound or VCTE from January 2023 to March 2024. Anthropometric, laboratory and non-invasive liver fibrosis evaluation parameters were used. The study assessed clinical characteristics and metabolic risk factors of patients with BMI ≤ 23 kg/m2 and BMI between 23 and ≤ 25 kg/m2 using MASLD and MAFLD diagnostic criteria.

Results

The cohort included NAFLD patients with a mean age of 43.3 years (±13.2 years). Of the participants, 33% were diagnosed through ultrasonography, whereas 67% diagnosis were made via Fibro scan. Majority were male 92 (83%), while females were 19 (17%) of the entire group. The lean NAFLD criteria for Asia and the West were satisfied by 43 (39%) persons with a BMI ≤ 23 kg/m2 and 68 (61%) individuals with a BMI between 23 and ≤ 25 kg/m2, respectively. The average body mass index (BMI) was 23.0 ± 1.5 kg/m2. Diabetes was observed in 16%, hypertension 11%, and ischemic heart disease in 2%. Out of the total individuals, 92 satisfied the MASLD-MAFLD criteria, whereas 18 did not qualify the MAFLD criteria for diagnosis and were classed as MASLD-Alone. Elevated triglycerides, insulin resistance (HOMA-IR ≥ 2), and three or more cardiometabolic risk factors (CMRF) were significant in the MASLD-MAFLD group compared to the MASLD-Alone group (p < 0.05). Comparing BMI criteria, no significant differences were found in terms of fibrosis between the Western and Asian lean NAFLD BMI criteria's (p = 0.243).

Conclusion

Lean NAFLD is a major global health concern. Applying non-Asian BMI criteria (BMI ≤ 25 kg/m2) for lean Asians improves early detection and intervention for at-risk individuals. Accurate use of MAFLD and MASLD criteria is essential to prevent confusion in diagnosing lean NAFLD. Further multicenter investigations with larger sample numbers are required to corroborate these results in our community.

How to cite this article

Nazir S, Abbas Z, Gazder DP, et al. Characterizing Nonalcoholic Fatty Liver Disease (NAFLD) in Lean Individuals at a Tertiary Care Hospital: A Cross-sectional Study. Euroasian J Hepato-Gastroenterol 2024;14(2):198-204.

Disparities among ethnic groups in mortality and outcomes among adults with MASLD: A multicenter study

BACKGROUND

Metabolic dysfunction-associated steatotic liver disease (MASLD) is the leading cause of chronic liver disease and 10%-20% occurs in lean individuals. There is little data in the literature regarding outcomes in an ethnically-diverse patient populations with MASLD. Thus, we aim to investigate the natural history and ethnic disparities of MASLD patients in a diverse population, and stratified by body mass index categories.

METHODS

We conducted a retrospective multicenter study on patients with MASLD at the Banner Health System from 2012 to 2022. Main outcomes included mortality and incidence of cirrhosis, cardiovascular disease, diabetes mellitus (DM), liver-related events (LREs), and cancer. We used competing risk and Cox proportional hazard regression analysis for outcome modelling.

RESULTS

A total of 51 452 (cross-sectional cohort) and 37 027 (longitudinal cohort) patients were identified with 9.6% lean. The cohort was 63.33% European ancestry, 27.96% Hispanic ancestry, 3.45% African ancestry, and 2.31% Native American/Alaskan ancestry. Median follow-up was 45.8 months. After adjusting for confounders, compared to European individuals, Hispanic and Native American/Alaskan patients had higher prevalence of cirrhosis and DM, and individuals of Hispanic, African, and Native American/Alaskan ancestry had higher mortality and incidence of LREs and DM. Lean patients had higher mortality and incidence of LREs compared with non-lean patients.

CONCLUSION

Native American/Alaskan, Hispanic, and African patients had higher mortality and incidence of LREs and DM compared with European patients. Further studies to explore the underlying disparities and intervention to prevent LREs in lean patients, particularly several ethnic groups, may improve clinical outcomes.

Serum Creatinine as an Independent Predictor of Moderate to Severe Fibrosis in Chinese American Non-obese Metabolic Dysfunction-Associated Steatotic Liver Disease

BACKGROUND

Metabolic dysfunction-associated steatotic liver disease (MASLD) is closely linked to the obesity epidemic. However, non-obese MASLD (body mass index [BMI] < 25 kg/m2 for Asians) is not uncommon, especially among Asian American populations. Preliminary research has demonstrated sarcopenia, a muscle-wasting syndrome, to be a major risk factor for non-obese Chinese MASLD. This study examined serum creatinine (SCr), a sarcopenia biomarker, and other prominent MASLD biomarkers for their ability to predict moderate to severe fibrosis (≥7.5 kPa or ≥F2 fibrosis) in the Chinese American MASLD population.

METHODS

A total of 296 Chinese American MASLD patients were categorized by BMI and fibrosis severity. As per World Health Organization guidelines for Asians, we identified obese MASLD (BMI ≥ 25 kg/m2) in 191 subjects (64.5%) and non-obese MASLD (BMI < 25 kg/m2) in 105 subjects (35.5%). Multivariate logistic regressions were performed to ascertain which biomarkers served as independent predictors of ≥F2 fibrosis. Wilcoxon signed-rank tests were conducted to compare MASLD cohorts (stratified by gender) and the healthy adult population on SCr distribution.

RESULTS

The obese MASLD cohorts had higher rates of ≥F2 fibrosis and type 2 diabetes mellitus compared to their older, non-obese counterparts. For obese MASLD patients, higher age (P < 0.05), increased BMI (P < 0.01), increased AST (P < 0.05), and decreased platelets (P < 0.05) independently predicted ≥F2 fibrosis. For non-obese MASLD patients, lowered SCr (P < 0.05) levels served as the main predictor of ≥F2 fibrosis. Female MASLD patients had markedly lower SCr distributions (P < 0.001) compared to the healthy female population, with 26.8% having SCr levels below the normal range.

CONCLUSIONS

In summary, SCr was the predominant predictor of moderate to severe fibrosis in non-obese Chinese American MASLD patients. The high rate of decreased SCr levels in Chinese American MASLD women suggests that this population may be at higher risk for muscle mass loss, which can lead to liver fat accumulation.

Update in lean metabolic dysfunction-associated steatotic liver disease

BACKGROUND

A new nomenclature consensus has emerged for liver diseases that were previously known as non-alcoholic fatty liver disease (NAFLD) and metabolic dysfunction-associated fatty liver disease (MAFLD). They are now defined as metabolic dysfunction-associated steatotic liver disease (MASLD), which includes cardiometabolic criteria in adults. This condition, extensively studied in obese or overweight patients, constitutes around 30% of the population, with a steady increase worldwide. Lean patients account for approximately 10%-15% of the MASLD population. However, the pathogenesis is complex and is not well understood.

AIM

To systematically review the literature on the diagnosis, pathogenesis, characteristics, and prognosis in lean MASLD patients and provide an interpretation of these new criteria.

METHODS

We conducted a comprehensive database search on PubMed and Google Scholar between January 2012 and September 2023, specifically focusing on lean NAFLD, MAFLD, or MASLD patients. We include original articles with patients aged 18 years or older, with a lean body mass index categorized according to the World Health Organization criteria, using a cutoff of 25 kg/m2 for the general population and 23 kg/m2 for the Asian population.

RESULTS

We include 85 studies in our analysis. Our findings revealed that, for lean NAFLD patients, the prevalence rate varied widely, ranging from 3.8% to 34.1%. The precise pathogenesis mechanism remained elusive, with associations found in genetic variants, epigenetic modifications, and adaptative metabolic response. Common risk factors included metabolic syndrome, hypertension, and type 2 diabetes mellitus, but their prevalence varied based on the comparison group involving lean patients. Regarding non-invasive tools, Fibrosis-4 index outperformed the NAFLD fibrosis score in lean patients. Lifestyle modifications aided in reducing hepatic steatosis and improving cardiometabolic profiles, with some medications showing efficacy to a lesser extent. However, lean NAFLD patients exhibited a worse prognosis compared to the obese or overweight counterpart.

CONCLUSION

MASLD is a complex disease comprising epigenetic, genetic, and metabolic factors in its pathogenesis. Results vary across populations, gender, and age. Limited data exists on clinical practice guidelines for lean patients. Future studies employing this new nomenclature can contribute to standardizing and generalizing results among lean patients with steatotic liver disease.

What Is New in Metabolic Dysfunction-Associated Steatotic Liver Disease in Lean Individuals: From Bench to Bedside

Metabolic dysfunction-associated steatotic liver disease (MASLD) affects more than 30% of the world's adult population. While it is associated with obesity and metabolic syndrome, emerging evidence has shown that a substantial number of MASLD patients have a normal body mass index ("lean individuals with MASLD"). In this article, we provide an overview of the definition, epidemiology, pathogenesis, and clinical outcomes associated with lean individuals with MASLD and updates on current management.

Clinical correlates of CT imaging-derived phenotypes among lean and overweight patients with hepatic steatosis

The objective of this study is to define CT imaging derived phenotypes for patients with hepatic steatosis, a common metabolic liver condition, and determine its association with patient data from a medical biobank. There is a need to further characterize hepatic steatosis in lean patients, as its epidemiology may differ from that in overweight patients. A deep learning method determined the spleen-hepatic attenuation difference (SHAD) in Hounsfield Units (HU) on abdominal CT scans as a quantitative measure of hepatic steatosis. The patient cohort was stratified by BMI with a threshold of 25 kg/m2 and hepatic steatosis with threshold SHAD ≥  - 1 HU or liver mean attenuation ≤ 40 HU. Patient characteristics, diagnoses, and laboratory results representing metabolism and liver function were investigated. A phenome-wide association study (PheWAS) was performed for the statistical interaction between SHAD and the binary characteristic LEAN. The cohort contained 8914 patients-lean patients with (N = 278, 3.1%) and without (N = 1867, 20.9%) steatosis, and overweight patients with (N = 1863, 20.9%) and without (N = 4906, 55.0%) steatosis. Among all lean patients, those with steatosis had increased rates of cardiovascular disease (41.7 vs 27.8%), hypertension (86.7 vs 49.8%), and type 2 diabetes mellitus (29.1 vs 15.7%) (all p < 0.0001). Ten phenotypes were significant in the PheWAS, including chronic kidney disease, renal failure, and cardiovascular disease. Hepatic steatosis was found to be associated with cardiovascular, kidney, and metabolic conditions, separate from overweight BMI.

Differential Mortality Outcomes in Real-world Patients with Lean, Nonobese, and Obese Nonalcoholic Fatty Liver Disease

Background and Aims

Nonalcoholic fatty liver disease (NAFLD) is commonly associated with obesity but can develop in normal-weight people (lean NAFLD). We compared outcomes in lean, overweight, and obese NAFLD.

Methods

This retrospective chart review included patients at Stanford University Medical Center with NAFLD confirmed by imaging between March 1995 and December 2021. Lean, overweight, and obese patients had body mass index of <25.0, >25.0 and <29.9, and ≥30.0 kg/m2 for non-Asian and >23.0 and ≥27.5 for overweight and obese Asian patients.

Results

A total of 9061 lean (10.2%), overweight (31.7%), and obese (58.1%) patients were included. Lean patients were 5 years older than obese patients (53±17.4 vs. 48.7±15.1 years), more were female (59.6% vs. 55.2%), white (49.1% vs. 46.5%), had NASH (29.2% vs. 22.5%), cirrhosis (25.3% vs.19.2%), or nonliver cancer (25.3% vs. 18.3%). Fewer had diabetes (21.7% vs. 35.8%) or metabolic comorbidities (all p<0.0001). Lean NAFLD patients had liver-related mortality similar to other groups but higher overall (p=0.01) and nonliver-related (p=0.02) mortality. After multivariable model adjustment for covariates, differences between lean and obese NAFLD in liver-related, nonliver-related, and overall mortality (adjusted hazard ratios of 1.34, 1.00, and 1.32; p=0.66, 0.99, and 0.20, respectively) were not significant.

Conclusions

Lean NAFLD had fewer metabolic comorbidities but similar adverse or worse outcomes, suggesting that it is not benign. Healthcare providers should provide the same level of care and intervention as for overweight and obese NAFLD.

Impact of anthropometric parameters on outcomes in Asians with metabolic dysfunction-associated fatty liver disease

BACKGROUND

We examined the incidence and predictors of clinical outcomes in metabolic dysfunction-associated fatty liver disease (MAFLD), focusing on anthropometric parameters.

METHODS

Adult patients with MAFLD were identified in nationwide databases and a hospital cohort. Primary endpoints were atherosclerotic cardiovascular disease (ASCVD) and advanced fibrosis. Logistic and Cox regression analyses were used to analyse the association between anthropometric parameters and endpoints.

RESULTS

In total, 4407 of 15 256 (28.9%) and 6274 of 25 784 subjects (24.3%) had MAFLD in the nationwide database; of these, 403 (9.2%) and 437 (7.0%) subjects were of lean/normal weight, respectively. Compared to the overweight/obese group, the lean/normal weight group had a significantly lower muscle mass (15.0 vs. 18.9 kg) and handgrip strength (31.9 vs. 35.1 kg) and had a higher ASCVD risk (9.0% vs. 6.3% and 15.9% vs. 8.5%; Ps < 0.001). Sarcopenia (odds ratio [OR], 6.66; 95% confidence interval [CI], 1.79-24.80) and handgrip strength (OR, 0.92; 95% CI, 0.86-0.97; Ps = 0.005) were associated with the ASCVD risk in the lean/normal weight group. In a hospital cohort (n = 1363), the ASCVD risk was significantly higher in the lean/normal weight group than in the overweight/obese group (median follow-up, 39.1 months). Muscle mass was inversely correlated with the ASCVD risk (hazard ratio [HR], 0.72; 95% CI, 0.56-0.94), while visceral adiposity was associated with advanced fibrosis (HR, 1.36; 95% CI, 1.10-1.69; Ps < 0.05).

CONCLUSIONS

Muscle mass/strength was significantly associated with the ASCVD risk in patients with MAFLD. Visceral adiposity was an independent predictor of advanced fibrosis.

Global burden of cirrhosis and other chronic liver diseases due to nonalcoholic fatty liver disease, 1990-2019

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) has become the leading cause of cirrhosis and other chronic liver diseases (COCLDs).

AIM

To conduct a comprehensive and comparable updated analysis of the global, regional, and national burden of COCLDs due to NAFLD in 204 countries and territories from 1990 and 2019 by age, sex, and sociodemographic index.

METHODS

Data on COCLDs due to NAFLD were collected from the Global Burden of Diseases, Injuries, and Risk Factors Study 2019. Numbers and age-standardized prevalence, death, and disability-adjusted life years (DALYs) were estimated through a systematic analysis of modelled data from the Global Burden of Diseases, Injuries, and Risk Factors Study 2019. The estimated annual percentage change was used to determine the burden trend.

RESULTS

In 2019, the global age-standardized prevalence rate of COCLDs due to NAFLD was 15022.90 per 100000 population [95% uncertainty interval (UI): 13493.19-16764.24], which increased by 24.51% (22.63% to 26.08%) from 1990, with an estimated annual percentage change of 0.78 (95% confidence interval: 0.74-0.82). In the same year, however, the age-standardized death rate and age-standardized DALYs per 100000 population were 1.66 (95%UI: 1.20-2.17) and 43.69 (95%UI: 31.28-58.38), respectively. North Africa and the Middle East had the highest prevalence rates of COCLDs due to NAFLD. The death rate increased with age up to the 95+ age group for both sexes. Males had higher numbers of prevalence, death rate, and DALYs than females across all age groups before the 65-69 age group. The sociodemographic index was negatively correlated with the age-standardized DALYs.

CONCLUSION

Globally, the age-standardized prevalence rate has increased during the past three decades. However, the age-standardized death rate and age-standardized DALYs decreased. There is geographical variation in the burden of COCLDs due to NAFLD. It is strongly recommended to improve the data quality of COCLDs due to NAFLD across all countries and regions to facilitate better monitoring of the burden of COCLDs due to NAFLD.

Clinical Classification of Obesity and Implications for Metabolic Dysfunction-Associated Fatty Liver Disease and Treatment

Obesity,and metabolic dysfunction-associated fatty liver disease (MAFLD) have reached epidemic proportions globally. Obesity and MAFLD frequently coexist and act synergistically to increase the risk of adverse clinical outcomes (both hepatic and extrahepatic). Type 2 diabetes mellitus (T2DM) is the most important risk factor for rapid progression of steatohepatitis and advanced fibrosis. Conversely, the later stages of MAFLD are associated with an increased risk of T2DM incident. According to the proposed criteria, MAFLD is diagnosed in patients with liver steatosis and in at least one in three: overweight or obese, T2DM, or signs of metabolic dysregulation if they are of normal weight. However, the clinical classification and correlation between obesity and MAFLD is more complex than expected. In addition, treatment for obesity and MAFLD are associated with a reduced risk of T2DM, suggesting that liver-based treatments could reduce the risk of developing T2DM. This review describes the clinical classification of obesity and MAFLD, discusses the clinical features of various types of obesity and MAFLD, emphasizes the role of visceral obesity and insulin resistance (IR) in the development of MAFLD,and summarizes the existing treatments for obesity and MAFLD that reduce the risk of developing T2DM.

Mortality and Liver-Related Events in Lean Versus Non-Lean Nonalcoholic Fatty Liver Disease: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

Although approximately 40% of patients with nonalcoholic fatty liver disease (NAFLD) are nonobese or lean, little is known about the long-term clinical outcomes of lean NAFLD. We aimed to estimate the risk of mortality and adverse liver-related events in patients with lean NAFLD compared with those with non-lean NAFLD.

METHODS

We searched the PubMed, Embase, and Cochrane Library databases through May 2022 for articles reporting mortality and/or development of cirrhosis among lean and non-lean NAFLD patients. The relative risks (RRs) of all-cause mortality, cardiovascular mortality, liver-related mortality, and occurrence of decompensated cirrhosis or hepatocellular carcinoma were pooled using the random-effects model. We also performed subgroup analysis according to characteristics of the study population, methods of NAFLD diagnosis, study design, study region, and length of follow-up.

RESULTS

We analyzed 10 cohort studies involving 109,151 NAFLD patients. Patients with lean NAFLD had comparable risks for all-cause mortality (RR, 1.09; 95% confidence interval [CI], 0.66-1.90), cardiovascular mortality (RR, 1.12; 95% CI, 0.66-1.90), and adverse liver events including decompensated cirrhosis and hepatocellular carcinoma (RR, 0.81; 95% CI, 0.50-1.30). However, the risk of liver-related mortality was higher in patients with lean than non-lean NAFLD (RR, 1.88; 95% CI, 1.02-3.45).

CONCLUSIONS

This study highlights a higher risk of liver-related mortality in patients with lean NAFLD than those with non-lean NAFLD. This finding indicates that further understanding of the pathophysiology, risk factors of adverse outcomes, and genetic and ethnic variabilities of lean NAFLD phenotype is warranted for individualized treatment strategies in lean NAFLD patients.

Lean individuals with NAFLD have more severe liver disease and poorer clinical outcomes (NASH-CO Study)

BACKGROUND AND AIMS

The severity of liver injury and clinical outcomes in lean individuals with NAFLD is a subject of debate and very few studies have been performed in the general population. The aim of this study was to compare subject characteristics and mortality between lean and nonlean NAFLD in a community setting.

APPROACH AND RESULTS

The study population included 169,303 participants from the nationwide Constances cohort. Subjects with excessive alcohol consumption, viral hepatitis, or other liver diseases were excluded and 137,206 subjects were analyzed. The diagnosis of NAFLD and fibrosis was performed using the Fatty Liver Index and the Forns Index. The median follow-up was 3.58 years. The prevalence of NAFLD was 5.3% (95% CI: 5.2-5.4) in lean subjects, while 16.3% (95% CI: 15.7-16.8) of NAFLD subjects were lean. Despite their better metabolic profile, the prevalence of advanced fibrosis was significantly higher in lean than in nonlean NAFLD (3.7% vs. 1.7%, respectively, p < 0.01). Among NAFLD subjects and after adjustment for demographics, metabolic risk factors and lifestyle, lean status was associated with advanced fibrosis (OR=1.26, 95% CI: 1.20-1.65, p = 0.005), an increased risk of liver-related events (adjusted HR=5.84, 95% CI: 4.03-8.46), chronic kidney disease (adjusted HR=2.49, 95% CI: 1.49-4.16), and overall mortality (adjusted HR=3.01, 95% CI: 2.21-4.11). Liver-related events and overall mortality were related to the severity of fibrosis, both in lean and nonlean NAFLD subjects, whatever the usual risk factors.

CONCLUSION

This study in a large community-based cohort confirms that NAFLD in lean subjects is more severe for fibrosis, the progression of liver disease, chronic kidney disease, and overall mortality.

Risk of cardiovascular disease in lean patients with nonalcoholic fatty liver disease

BACKGROUND

Patients with nonalcoholic fatty liver disease (NAFLD) are highly at risk for cardiovascular disease (CVD). However, the risk of developing CVD in patients with lean NAFLD is not yet fully understood. Therefore, this study aimed to compare the CVD incidence in Japanese patients with lean NAFLD and those with non-lean NAFLD.

METHODS

A total of 581 patients with NAFLD (219 with lean and 362 with non-lean NAFLD) were recruited. All patients underwent annual health checkups for at least 3 years, and CVD incidence was investigated during follow-up. The primary end-point was CVD incidence at 3 years.

RESULTS

The 3-year new CVD incidence rates in patients with lean and non-lean NAFLD were 2.3% and 3.9%, respectively, and there was no significant difference between two groups (p = 0.3). Multivariable analysis adjusted for age, sex, hypertension, diabetes, and lean NAFLD/non-lean NAFLD revealed that age (every 10 years) as an independent factor associated with CVD incidence with an odds ratio (OR) of 2.0 (95% confidence interval [CI]: 1.3-3.4), whereas lean NAFLD was not associated with CVD incidence (OR: 0.6; 95% CI: 0.2-1.9).

CONCLUSIONS

CVD incidence was comparable between patients with lean NAFLD and those with non-lean NAFLD. Therefore, CVD prevention is needed even in patients with lean NAFLD.

Higher mortality among lean patients with non-alcoholic fatty liver disease despite fewer metabolic comorbidities

BACKGROUND & AIMS

Non-alcoholic fatty liver disease (NAFLD) can develop in individuals who are not overweight. Whether lean persons with NAFLD have lower mortality and lower incidence of cirrhosis, cardiovascular diseases (CVD), diabetes mellitus (DM) and cancer than overweight/obese persons with NAFLD remains inconclusive. We compared mortality and incidence of cirrhosis, CVD, DM and cancer between lean versus non-lean persons with NAFLD.

METHODS

This is a retrospective study of adults with NAFLD in a single centre from 2012 to 2021. Primary outcomes were mortality and new diagnosis of cirrhosis, CVD, DM and cancer. Outcomes were modelled using competing risk analysis and Cox proportional hazards regression analysis.

RESULTS

A total of 18,594 and 13,420 patients were identified for cross-sectional and longitudinal analysis respectively: approximately 11% lean, 25% overweight, 28% class 1 obesity and 35% class 2-3 obesity. The median age was 51.0 years, 54.6% were women. The median follow-up was 49.3 months. Lean patients had lower prevalence of metabolic diseases at baseline and lower incidence of cirrhosis and DM than non-lean patients and no difference in CVD, any cancer or obesity-related cancer during follow-up. However, lean patients had significantly higher mortality with incidence per 1000 person-years of 16.67, 10.11, 7.37 and 8.99, respectively, in lean, overweight, obesity class 1 and obesity class 2-3 groups respectively.

CONCLUSIONS

Lean patients with NAFLD had higher mortality despite lower incidence of cirrhosis and DM, and similar incidence of CVD and cancer and merit similar if not more attention as non-lean patients with NAFLD.

Metabolic dysfunction and nonalcoholic fatty liver disease risk in individuals with a normal body mass index

PURPOSE OF REVIEW

Nonalcoholic fatty liver disease (NAFLD) is strongly associated with obesity, but is also common in individuals with a normal body mass index (BMI), who also experience the hepatic inflammation, fibrosis, and decompensated cirrhosis associated with NAFLD progression. The clinical evaluation and treatment of NAFLD in this patient population are challenging for the gastroenterologist. A better understanding of the epidemiology, natural history, and outcomes of NAFLD in individuals with normal BMI is emerging. This review examines the relationship between metabolic dysfunction and clinical characteristics associated with NAFLD in normal-weight individuals.

RECENT FINDINGS

Despite a more favorable metabolic profile, normal-weight NAFLD patients exhibit metabolic dysfunction. Visceral adiposity may be a critical risk factor for NAFLD in normal-weight individuals, and waist circumference may be better than BMI for assessing metabolic risk in these patients. Although screening for NAFLD is not presently recommended, recent guidelines may assist clinicians in the diagnosis, staging, and management of NAFLD in individuals with a normal BMI.

SUMMARY

Individuals with a normal BMI likely develop NAFLD as a result of different etiologies. Subclinical metabolic dysfunction may be a key component of NAFLD in these patients, and efforts to better understand this relationship in this patient population are needed.

Special Population: Lean Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is strongly associated with obesity but around 10% to 20% of patients with NAFLD have normal body mass index, a condition referred to as lean or nonobese NAFLD. Although lean patients more often have milder liver disease, a proportion may nonetheless develop steatohepatitis and advanced liver fibrosis. Both genetic and environmental factors contribute to the development of NAFLD. Noninvasive tests have similarly good accuracy as initial assessments for lean NAFLD. Future studies should determine the most appropriate treatment in this special population.

Clinical features of chronic hepatitis B patients with lean nonalcoholic fatty liver disease

BACKGROUND

The clinical features have been well described in obese chronic hepatitis B (CHB) patients with nonalcoholic fatty liver disease (NAFLD). However, little is known about the clinical features of lean CHB-NAFLD patients.

METHODS

The study retrospectively included treatment-naïve CHB patients who underwent ultrasound between 2015 and 2021. Liver fibrosis was assessed by aspartate aminotransferase (AST) to platelet ratio index (APRI), Fibrosis-4 score (FIB-4), NAFLD fibrosis score (NFS), and transient elastography.

RESULTS

Among 1226 CHB-NAFLD patients, 25.0% patients were lean. The age, gender, and platelet, alanine aminotransferase, AST, and albumin levels were comparable between lean CHB-NAFLD and nonlean patients. The levels of plasma glucose, triglycerides, total cholesterol, and uric acid, as well as proportions of concurrent hypertension and diabetes, were lower in lean patients. Lean patients presented higher hepatitis B surface antigen (HBsAg) levels (3.4 log₁₀ IU/ml vs. 3.2 log₁₀ IU/ml, p = 0.006), hepatitis B virus (HBV) DNA levels (4.1 log₁₀ IU/ml vs. 3.2 log₁₀ IU/ml, p < 0.001), and hepatitis B e antigen (HBeAg) positive proportions (40.4% vs. 30.2%, p = 0.002) than nonlean patients. The values of APRI, FIB-4, and liver stiffness were comparable between two groups. However, lean patients had lower NFS values (-3.0 vs. -2.6, p < 0.001) and lower proportions (12.6% vs. 21.1%, p = 0.003) of advanced fibrosis (NFS ≥ -1.5) than nonlean patients. Similar results were observed in HBeAg-positive and HBeAg-negative subgroups.

CONCLUSIONS

Nearly a quarter of CHB-NAFLD patients were lean. Lean patients had lower proportions of metabolic abnormalities and advanced liver fibrosis than nonlean patients. However, lean CHB-NAFLD patients had higher HBsAg levels, HBV DNA levels, and HBeAg-positive proportions. Registry and registration no. of the study/trial: Clinicaltrials.gov, Identifier: NCT03097952.

Underestimation of Cirrhosis-Related Mortality in the Medicare Eligible Population, 1999-2018

The burden of cirrhosis may be increasing, especially among the elderly. A recent updated definition of cirrhosis has a >90% positive predictive value for identifying cirrhosis and cirrhosis-related complications.¹ We hypothesized that cirrhosis-related mortality is underestimated, and that the elderly are disproportionally impacted. In this study, we aimed to examine trends in liver-related mortality using this updated definition among the elderly and to identify changes by relevant subsets of gender, race, and rurality.

Epidemiology of liver cirrhosis and associated complications: Current knowledge and future directions

Cirrhosis causes a heavy global burden. In this review, we summarized up-to-date epidemiological features of cirrhosis and its complications. Recent epidemiological studies reported an increase in the prevalence of cirrhosis in 2017 compared to in 1990 in both men and women, with 5.2 million cases of cirrhosis and chronic liver disease occurring in 2017. Cirrhosis caused 1.48 million deaths in 2019, an increase of 8.1% compared to 2017. Disability-adjusted life-years due to cirrhosis ranked 16th among all diseases and 7th in people aged 50-74 years in 2019. The global burden of hepatitis B virus and hepatitis C virus-associated cirrhosis is decreasing, while the burden of cirrhosis due to alcohol and nonalcoholic fatty liver disease (NAFLD) is increasing rapidly. We described the current epidemiology of the major complications of cirrhosis, including ascites, variceal bleeding, hepatic encephalopathy, renal disorders, and infections. We also summarized the epidemiology of hepatocellular carcinoma in patients with cirrhosis. In the future, NAFLD-related cirrhosis will likely become more common due to the prevalence of metabolic diseases such as obesity and diabetes, and the prevalence of alcohol-induced cirrhosis is increasing. This altered epidemiology should be clinically noted, and relevant interventions should be undertaken.

Outcomes of subjects who are lean, overweight or obese with nonalcoholic fatty liver disease: A cohort study in China

The ability to determine the prognosis of lean nonalcoholic fatty liver disease (NAFLD) is essential for decision making in clinical settings. Using a large community-based Chinese cohort, we aimed to investigate NAFLD outcomes by body mass index (BMI). We used the restricted cubic splines method to investigate the dose-response relationship between BMI and outcomes in subjects with NAFLD and those without NAFLD. We included 73,907 subjects from the Kailuan cohort and grouped all subjects into four phenotypes by using NAFLD and BMI (<23 kg/m² ). The probability of developing outcomes for individuals with lean NAFLD (LN), overweight/obese NAFLD (ON), overweight/obese non-NAFLD (ONN), and lean non-NAFLD (LNN) was estimated. We found a U-shaped association between BMI and death but a linear positive association concerning cardiovascular disease (CVD) after adjusting for age and other covariates. Compared with the LNN group, the adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) of the LN, ON, and ONN groups were 1.30 (1.14-1.49), 0.86 (0.80-0.91), 0.84 (0.80-0.89) for all-cause death, 2.61 (1.13-6.03), 0.74 (0.44-1.26), 1.10 (0.70-1.74) for liver-related death, 2.12 (1.46-3.08), 1.23 (0.99-1.54), 1.19 (0.98-1.43) for digestive system cancers, and 2.04 (1.40-2.96), 1.30 (1.05-1.61), 1.21 (1.01-1.46) for obesity-related cancers. Subjects with LN had a significantly higher risk of colorectal cancer and esophagus cancer. However, the ON group had the highest CVD risk (HR, 1.39; 95% CI, 1.27-1.52). The LN group with hypertension had a higher risk of adverse outcomes, and those without hypertension had a similar risk compared to LNN. Conclusion: Subjects with LN may experience a higher risk of all-cause death, digestive system cancers, and obesity-related cancers than the other three groups but a lower risk of CVD than ON subjects. LN with hypertension may be a high-risk phenotype.

The Attitude of Practitioners Towards Endoscopic Sleeve Gastroplasty

BACKGROUND AND AIM

Despite widespread adoption and encouraging results seen over the last 5 years, no consensus exists regarding the endoscopic sleeve gastroplasty (ESG) technique, training, or preprocedure and postprocedure management of the patient. The aim of our survey was to assess practice trends and preferences of bariatric endoscopists with respect to ESG.

METHODS

Using a digital platform, we conducted a worldwide survey by emailing a link with an electronic questionnaire to 1200 bariatric endoscopists trained to perform endoscopic suturing using the Apollo Overstitch suturing device (Apollo Endosurgery).

RESULTS

We received 221 responses that were included in the analysis. Fifty-one responders (36.4%) required 1 to 10 procedures, and 37 (26.4%) needed 11 to 20 procedures to become proficient at ESG. Ninety-six (68.6%) stated that lower body mass index thresholds should be adopted for Asian and Arab patients. There was no consensus on the ideal number of sutures, with 45 (32.1%), 42 (30%), 36 (25.7%), 13 (9.3%), and 4 (2.9%) recommending 4 to 6, 5 to 7, 6 to 8, 7 to 9, and 8 to 12 sutures, respectively. The primary barriers to establishing an endobariatric program were the inability to establish a cash pay model, 77 (95.1%); lack of institutional support, 61 (75.3%); and difficulty in establishing an ambulatory surgical center/hospital to perform ESG, 73 (90.1%).

CONCLUSIONS

ESG practice trends remain heterogenous among practitioners in regard to indication, technique, and preprocedure and postprocedure management. Specific ESG guidelines are warranted, and this survey will assist in providing the framework for these guidelines to be written.

Metabolic (dysfunction)-associated fatty liver disease in individuals of normal weight

Metabolic (dysfunction)-associated fatty liver disease (MAFLD) affects up to a third of the global population; its burden has grown in parallel with rising rates of type 2 diabetes mellitus and obesity. MAFLD increases the risk of end-stage liver disease, hepatocellular carcinoma, death and liver transplantation and has extrahepatic consequences, including cardiometabolic disease and cancers. Although typically associated with obesity, there is accumulating evidence that not all people with overweight or obesity develop fatty liver disease. On the other hand, a considerable proportion of patients with MAFLD are of normal weight, indicating the importance of metabolic health in the pathogenesis of the disease regardless of body mass index. The clinical profile, natural history and pathophysiology of patients with so-called lean MAFLD are not well characterized. In this Review, we provide epidemiological data on this group of patients and consider overall metabolic health and metabolic adaptation as a framework to best explain the pathogenesis of MAFLD and its heterogeneity in individuals of normal weight and in those who are above normal weight. This framework provides a conceptual schema for interrogating the MAFLD phenotype in individuals of normal weight that can translate to novel approaches for diagnosis and patient care.

AGA Clinical Practice Update: Diagnosis and Management of Nonalcoholic Fatty Liver Disease in Lean Individuals: Expert Review

DESCRIPTION

Nonalcoholic fatty liver disease (NAFLD) is well recognized as a leading etiology for chronic liver disease, affecting >25% of the US and global populations. Up to 1 in 4 individuals with NAFLD have nonalcoholic steatohepatitis, which is associated with significant morbidity and mortality due to complications of liver cirrhosis, hepatic decompensation, and hepatocellular carcinoma. Although NAFLD is observed predominantly in persons with obesity and/or type 2 diabetes mellitus, an estimated 7%-20% of individuals with NAFLD have lean body habitus. Limited guidance is available to clinicians on appropriate clinical evaluation in lean individuals with NAFLD, such as for inherited/genetic disorders, lipodystrophy, drug-induced NAFLD, and inflammatory disorders. Emerging data now provide more robust evidence to define the epidemiology, natural history, prognosis, and mortality of lean individuals with NAFLD. Multiple studies have found that NAFLD among lean individuals is associated with increased cardiovascular, liver, and all-cause mortality relative to those without NAFLD. This American Gastroenterological Association Clinical Practice Update provides Best Practice Advice to assist clinicians in evidence-based approaches to the diagnosis, staging, and management of NAFLD in lean individuals.

METHODS

This expert review was commissioned and approved by the American Gastroenterological Association (AGA) Institute Clinical Practice Updates Committee and the AGA Governing Board to provide timely guidance on a topic of high clinical importance to the AGA membership and underwent internal peer review by the Clinical Practice Updates Committee and external peer review through standard procedures of Gastroenterology. Best Practice Advice Statements BEST PRACTICE ADVICE 1: Lean NAFLD should be diagnosed in individuals with NAFLD and body mass index <25 kg/m2 (non-Asian race) or body mass index <23 kg/m2 (Asian race). BEST PRACTICE ADVICE 2: Lean individuals with NAFLD should be evaluated routinely for comorbid conditions, such as type 2 diabetes mellitus, dyslipidemia, and hypertension. BEST PRACTICE ADVICE 3: Lean individuals with NAFLD should be risk stratified for hepatic fibrosis to identify those with advanced fibrosis or cirrhosis. BEST PRACTICE ADVICE 4: Lean individuals in the general population should not undergo routine screening for NAFLD; however, screening should be considered for individuals older than 40 years with type 2 diabetes mellitus. BEST PRACTICE ADVICE 5: NAFLD should be considered in lean individuals with metabolic diseases (such as type 2 diabetes mellitus, dyslipidemia, and hypertension), elevated liver biochemical tests, or incidentally noted hepatic steatosis. BEST PRACTICE ADVICE 6: Clinicians should query patients routinely regarding alcohol consumption patterns in all patients with lean NAFLD. BEST PRACTICE ADVICE 7: In patients with lean NAFLD, other causes of liver disease should be ruled out, including other causes of fatty liver, such as HIV, lipodystrophy, lysosomal acid lipase deficiency, familial hypobetalipoproteinemia, and medication-induced hepatic steatosis (methotrexate, amiodarone, tamoxifen, and steroids). BEST PRACTICE ADVICE 8: Current evidence is inadequate to support routine testing for genetic variants in patients with lean NAFLD. BEST PRACTICE ADVICE 9: Liver biopsy, as the reference standard, should be considered if there is uncertainty regarding contributing causes of liver injury and/or the stage of liver fibrosis. BEST PRACTICE ADVICE 10: Serum indices (NAFLD fibrosis score and Fibrosis-4 score) and imaging techniques (transient elastography and magnetic resonance elastography) may be used as alternatives to liver biopsy for fibrosis staging and patient follow-up. These tests can be performed at the time of diagnosis and repeated at intervals of 6 months to 2 years, depending on fibrosis stage and the patient's response to intervention. BEST PRACTICE ADVICE 11: If noninvasive tests (eg, Fibrosis-4 and NAFLD fibrosis score) are indeterminate, a second noninvasive test (eg, transient elastography or magnetic resonance elastography) should be performed to confirm the stage and prognosis of NAFLD. BEST PRACTICE ADVICE 12: In lean patients with NAFLD, lifestyle intervention, including exercise, diet modification, and avoidance of fructose- and sugar-sweetened drinks, to target a modest weight loss of 3%-5% is suggested. BEST PRACTICE ADVICE 13: Administration of vitamin E may be considered in lean persons with biopsy-confirmed nonalcoholic steatohepatitis, but without type 2 diabetes mellitus or cirrhosis. Oral pioglitazone 30 mg daily may be considered in lean persons with biopsy-confirmed nonalcoholic steatohepatitis without cirrhosis. BEST PRACTICE ADVICE 14: The therapeutic role of glucagon-like peptide-1 agonists and sodium-glucose cotransporter-2 inhibitors in the management of lean NAFLD is not fully defined and requires further investigation. BEST PRACTICE ADVICE 15: Hepatocellular carcinoma surveillance with abdominal ultrasound with or without serum α-fetoprotein twice per year is suggested in patients with lean NAFLD and clinical markers compatible with liver cirrhosis.

Relationship between lifestyle and metabolic factors and carotid atherosclerosis: A survey of 47,063 fatty and non-fatty liver patients in China

Background and aims

Carotid atherosclerosis and stenosis are common lesions of the artery wall that form the basis of cardiovascular events. Compared with coronary atherosclerosis, few studies have explored the influencing factors of carotid atherosclerosis. The aim of this study was to explore the influencing factors of carotid atherosclerosis and carotid stenosis without and with fatty liver disease (FLD).

Methods

A total of 47,063 adults were recruited for this cross-sectional study. The color Doppler ultrasound, including metabolic factors and lifestyle surveys, was used to determine whether the participants had FLD and carotid artery disease. Multiple logistic regression was used to investigate the influencing factors of lifestyle and metabolism of carotid atherosclerosis and stenosis in the participants with and without FLD.

Results

In participants without FLD, current alcohol consumption (OR: 0.749, 95% CI: 0.588) and hip circumference (OR: 0.970, 95% CI: 0.961, 0.979) were the main protective factors for carotid atherosclerosis. Systolic blood pressure (OR: 1.022, 95% CI: 1.019, 1.025) and diastolic blood pressure (OR: 1.005, 95% CI: 1.001, 1.010), elevated fasting blood glucose (OR: 1.012, 95% CI: 1.005, 1.019), and non-sedentary behavior (OR: 1.084, 95% CI: 1.014, 1.160) were the main risk factors for carotid atherosclerosis. Hip circumference (OR: 0.932, 95% CI: 0.910, 0.954) and low-density lipoprotein (OR: 0.979, 95% CI: 0.964, 0.994) were protective factors for carotid stenosis. Smoking (OR: 3.525, 95% CI: 1.113, 11.169) and unqualified exercise (OR: 1.402, 95% CI: 1.083, 1.815) were risk factors for carotid stenosis. In participants with FLD, smoking (OR: 0.827, 95% CI: 0.703, 0.973) and hip circumference (OR: 0.967, 95% CI: 0.958, 0.977) were the main protective factors for carotid atherosclerosis. BMI 18.5–23.9 (OR: 1.163, 95% CI: 1.002, 1.351), non-sedentary behavior (OR: 1.086, 95% CI: 1.009, 1.168), and waist circumference (OR: 1.030, 95% CI: 1.022, 1.038) were the main risk factors for carotid atherosclerosis.

Conclusion

Based on a large-sample check-up population in China, this study investigated the influencing factors of carotid atherosclerosis and carotid stenosis in fatty liver and non-fatty liver patients and explored the influencing factors of metabolism and lifestyle, which were mainly focused on exercise, sedentary behavior, smoking, alcohol consumption, hip circumference, and blood pressure.

Comparative Burden of Metabolic Dysfunction in Lean NAFLD vs Non-lean NAFLD - A Systematic Review and Meta-analysis

BACKGROUND & AIMS

Nonalcoholic fatty liver disease (NAFLD) is traditionally associated with obesity. However, there is a subtype of NAFLD, namely NAFLD in lean, that occurs without obesity. However, a recent call to redefine NAFLD to metabolic-associated fatty liver disease focuses on obesity and metabolic dysfunction. Criticism has arisen from the perceived over emphasis on systemic comorbidities, which may disadvantage the lean. The current analysis seeks to quantify the degree of metabolic dysfunction in NAFLD in lean and compare with NAFLD in overweight and obese and non-NAFLD.

METHODS

Medline and Embase databases were searched from inception to March 3, 2022. The inclusion criteria were articles with NAFLD in lean patients presenting with baseline metabolic parameters. Comparisons were conducted with subgroup analysis.

RESULTS

Eighty-five articles were included in the meta-analysis. NAFLD in lean accounted for 13.11% (95% confidence interval [CI], 10.26%-16.62%) of the global population and 14.55% (95% CI, 11.32%-18.51%) in Asia. The degree of metabolic dysfunction was weight dependent with significantly less metabolic dysfunction in NAFLD in lean subjects as compared with NAFLD in overweight counterparts. For NAFLD in lean, only 19.56% (95% CI, 15.28%-24.69%) of the subjects were diabetic, whereas 45.70% (95% CI, 35.01%-56.80%) of obese subjects with NAFLD had diabetes (P < .01). Fasting blood glucose and systolic and diastolic blood pressure values were significantly lower in subjects with NAFLD in lean than in overweight and obese.

CONCLUSION

The current analysis highlights the weight-dependent nature of metabolic dysfunction in NAFLD. Lean subjects with NAFLD were significantly less metabolically unhealthy than were obese and overweight persons with NAFLD. An overreliance on metabolic dysfunction in defining fatty liver will be a flaw in potentially excluding previously characterized NAFLD.

The Impact of Insulin Resistance on Hepatic Fibrosis among United States Adults with Non-Alcoholic Fatty Liver Disease: NHANES 2017 to 2018

BACKGRUOUND

We aimed to investigate the association of hepatic steatosis with liver fibrosis and to assess the interactive effects of hepatic steatosis and insulin resistance on liver fibrosis in a nationally representative sample of United States adults.

METHODS

We conducted a cross-sectional analysis using data from National Health and Nutrition Examination Survey 2017 to 2018, which for the first time included transient elastography to assess liver stiffness and hepatic steatosis. We evaluated the association between hepatic steatosis (using controlled attenuation parameter [CAP]) and clinically significant liver fibrosis (defined as liver stiffness ≥7.5 kPa) using logistic regression with an interaction term for hepatic steatosis and insulin resistance (defined as homeostatic model assessment of insulin resistance ≥3.0).

RESULTS

Among adults undergoing transient elastography (n=2,023), 45.9% had moderate or greater hepatic steatosis and 11.3% had clinically significant liver fibrosis. After adjustment for demographic and metabolic factors, the odds of significant liver fibrosis increased as CAP score rose (odds ratio, 1.35 per standard deviation increment; 95% confidence interval, 1.11 to 1.64). We detected a significant interaction effect between CAP score and insulin resistance on the probability of significant liver fibrosis (P=0.016 for interaction). The probability of significant liver fibrosis increased in the presence of insulin resistance with increasing CAP score, while those without insulin resistance had low probability of significant liver fibrosis, even with high CAP scores.

CONCLUSION

Individuals with hepatic steatosis had higher odds of fibrosis when insulin resistance was present. Our findings emphasize the importance of the metabolic aspects of the disease on fibrosis risk and suggest a need to better identify patients with metabolic associated fatty liver disease.

Metabolic abnormalities, liver and body fat in American versus Chinese patients with non‐alcoholic fatty liver disease

Background and Aim

Non‐alcoholic fatty liver disease (NAFLD) is common in the United States and China. We compared prevalence of metabolic syndrome (MS), hepatic steatosis and fibrosis, and quantity and quality of body fat between American versus Chinese patients with NAFLD.

Methods

NAFLD patients were prospectively recruited from the University of Michigan Health System (UMHS) in the United States and Peking University Health Sciences Center (PUHSC) in China. All patients had baseline computed tomography (CT), laboratory tests and Fibroscan® controlled attenuation parameter (CAP) and liver stiffness measurement (LSM). Comparisons were made for overall cohorts and matched cohorts (matched for sex, age, and body mass index [BMI] category). Logistic regression was performed to identify independent predictors of moderate and severe steatosis and lack of advanced fibrosis.

Results

One‐hundred and one American and One‐hundred and sixty Chinese patients were included. UMHS patients were older, with higher prevalence of MS, had higher LSM and CAP scores, and more fat in liver, visceral, subcutaneous, and muscle compartments than PUHSC patients. Differences in LSM, visceral fat Hounsfield unit, and subcutaneous fat area (SFA) persisted in the matched cohort. NAFLD patients with MS had significantly higher LSM, and more fat in liver, visceral, subcutaneous and muscle compartments than those without. Moderate or severe steatosis was independently associated with MS, visceral fat quality, and SFA, while the absence of advanced fibrosis was associated with Asian race and not having MS.

Conclusion

American patients with NAFLD had more liver fibrosis than Chinese patients despite having better quality visceral fat and after matching for age, sex, and BMI category.

Nonalcoholic fatty liver disease prevalence and severity in Asian Americans from the national health and nutrition examination surveys 2017–2018

Studies have examined nonalcoholic fatty liver disease (NAFLD) prevalence and severity in Asians; however, this is not well understood in Asian Americans (both East and South Asian Americans) as few studies have analyzed this population. We aimed to describe characteristics, prevalence of NAFLD, and its severity in Asian Americans in the National Health and Nutrition Examination Surveys (NHANES) from 2017 to 2018. Respondents 18 years and older with interview, laboratory testing, and transient elastography data were included. Other causes of liver disease were excluded. Controlled attenuation parameter (CAP) cutoff ≥ 274 dB/m, as published in the literature, defined NAFLD. Sensitivity analysis for CAP cutoffs ≥ 248 and ≥302 dB/m were performed. We found that 450 out of 3639 respondents were Asian Americans, and prevalence using CAP ≥ 274 dB/m was 43.23%. Using sensitivity analysis cutoffs of CAP ≥ 248 dB/m and CAP ≥ 302 dB/m, the prevalence was 57.38% and 28.03%, respectively. Compared with non‐Asian Americans with NAFLD, Asian Americans with NAFLD had significantly lower body mass index (BMI) and less prevalent smoking history. Comorbidities, such as prediabetes, diabetes, and hypertension, were not significantly different between Asian and non‐Asian Americans with NAFLD. Compared to non‐Asian Americans with NAFLD, Asian Americans with NAFLD exhibited higher aminotransferases and triglycerides. Fibrosis assessed by transient elastography was not significantly different between Asian and non‐Asian Americans with NAFLD. Despite decreased prevalence of BMI ≥ 30 kg/m², Asian Americans experienced similar NAFLD prevalence with increased hepatocellular injury and triglyceridemia compared to non‐Asian Americans. Fibrosis stages were similar to non‐Asian Americans.

Knowledge Gaps, Challenges, and Opportunities in Health and Prevention Research for Asian Americans, Native Hawaiians, and Pacific Islanders: A Report From the 2021 National Institutes of Health Workshop

Asian Americans (AsA), Native Hawaiians, and Pacific Islanders (NHPI) comprise 7.7% of the U.S. population, and AsA have had the fastest growth rate since 2010. Yet the National Institutes of Health (NIH) has invested only 0.17% of its budget on AsA and NHPI research between 1992 and 2018. More than 40 ethnic subgroups are included within AsA and NHPI (with no majority subpopulation), which are highly diverse culturally, demographically, linguistically, and socioeconomically. However, data for these groups are often aggregated, masking critical health disparities and their drivers. To address these issues, in March 2021, the National Heart, Lung, and Blood Institute, in partnership with 8 other NIH institutes, convened a multidisciplinary workshop to review current research, knowledge gaps, opportunities, barriers, and approaches for prevention research for AsA and NHPI populations. The workshop covered 5 domains: 1) sociocultural, environmental, psychological health, and lifestyle dimensions; 2) metabolic disorders; 3) cardiovascular and lung diseases; 4) cancer; and 5) cognitive function and healthy aging. Two recurring themes emerged: Very limited data on the epidemiology, risk factors, and outcomes for most conditions are available, and most existing data are not disaggregated by subgroup, masking variation in risk factors, disease occurrence, and trajectories. Leveraging the vast phenotypic differences among AsA and NHPI groups was identified as a key opportunity to yield novel clues into etiologic and prognostic factors to inform prevention efforts and intervention strategies. Promising approaches for future research include developing collaborations with community partners, investing in infrastructure support for cohort studies, enhancing existing data sources to enable data disaggregation, and incorporating novel technology for objective measurement. Research on AsA and NHPI subgroups is urgently needed to eliminate disparities and promote health equity in these populations.

Liver biopsy in the real world-reporting, expert concordance and correlation with a pragmatic clinical diagnosis

BACKGROUND

Patients with non-alcoholic steatohepatitis (NASH) and fibrosis stage ≥2 comprise a target population for pharmacotherapy. Liver biopsy, the reference standard for identifying this population, requires complete and accurate assessment of steatohepatitis and fibrosis. Aims To investigate the completeness of real-world NASH-related pathology reports, assess concordance between site pathologists and central expert interpretation of the histologic elements of NASH, and determine concordance between biopsy-diagnosed NASH and a pragmatic clinical definition of NASH.

METHODS

Liver pathology reports from 222 patients across 38 TARGET-NASH sites were analysed for documentation of the histologic features of NASH. Biopsy slides were over-read by a blinded central expert pathologist. Concordance of histologic scores and interpretation was assessed. Histologic concordance with a clinical definition of NASH was determined. TARGET-NASH clinically defined NASH: elevated ALT, hepatic steatosis on biopsy or imaging and ≥1 of the following: BMI ≥30 kg/m2 , type 2 diabetes mellitus and dyslipidaemia.

RESULTS

Documentation of steatosis, lobular inflammation, portal inflammation and ballooning were missing from 21%, 35%, 46% and 40% of reports, respectively. There was slight-to-fair concordance (weighted kappa 0.01-0.35) between site and central pathologists for inflammatory features, and moderate concordance (weighted kappa 0.56-0.57) for fibrosis staging. Clinical definition of NASH was 75%-91% concordant (94%-95% sensitive) with biopsy-diagnosed NASH.

CONCLUSIONS

There is substantial variability in reporting and grading NASH and fibrosis staging in clinical practice. This heterogeneity may adversely impact patient assessment and translation of practice guidelines into reality. The TARGET-NASH pragmatic clinical definition may serve as a valuable tool to accurately identify NASH patients in clinical practice.

A Retrospective Study of Hospitalizations in the USA: Proportion of Hospitalizations With Non-Alcoholic Fatty Liver Disease in Non-Obese Population

Background Non-alcoholic fatty liver disease (NAFLD), one of the leading causes of end-stage liver disease, is known to be associated with obesity. However, only a few studies in the United States (US) have described non-obese NAFLD, most of which were on the outpatient population. Aim We aimed to investigate the proportion of hospitalizations in the US with a diagnosis code that included NAFLD in the non-obese population. Methods We analyzed adult discharges from the Nationwide Inpatient Sample with a diagnosis of NAFLD from January 2010 to December 2014. We created two groups: obese (overweight or obese) and non-obese (normal or underweight) groups. Basic demographic and clinical characteristics were compared using the chi-square test and Student's t-test. Results A total of 194,787 hospitalizations with NAFLD were identified over the five-year period. It was observed that the prevalence of non-obese NAFLD hospitalizations increased yearly. Non-obese NAFLD hospitalizations had a higher mean age (57.5 vs 51.5 years, p < 0.0001) and a higher proportion of males (43.3% vs 36.1%, p < 0.0001) than obese NAFLD hospitalizations. With univariate analysis, non-obese NAFLD hospitalizations had lower odds of hypertension (OR 0.74, p < 0.0001), diabetes mellitus (OR 0.65, p < 0.0001). Non-obese hospitalizations had higher odds of cirrhosis (OR 1.30, p < 0.001) and decompensated cirrhosis (OR 1.30, p < 0.001) after adjusting for age, sex, race, diabetes mellitus, and dyslipidemia. Hospitalizations with non-obese NAFLD had higher odds of death (OR 1.49, p < 0.001) after adjusting for age, gender, race, co-morbidities, cirrhosis, and liver decompensation. Conclusion There is a continued rise in the proportion of non-obese NAFLD among hospitalizations in the US. Non-obese NAFLD hospitalizations were less likely to have hypertension and diabetes, but more likely to have decompensated liver disease. Further studies are needed to better characterize these patients to enable early detection, treatment, and reduction in complications of liver disease.

Diabetes and metabolic dysfunction-associated fatty liver disease

Metabolic dysfunction-associated fatty liver disease (MAFLD) is a relatively novel classification which downplays the importance of alcohol in the definition of non-alcoholic fatty liver disease (NAFLD) and emphasizes the metabolic risk factors that underlie progression of NAFLD-associated pathology. All people with type 2 diabetes (T2D) and hepatic fat content >5% by biomarkers, imaging or biopsy are considered to have MAFLD. Since there have been very few published studies of MAFLD in diabetes, the present review assesses contemporary methods for quantifying liver fat and fibrosis (including those based on magnetic resonance imaging) with special reference to T2D, their prognostic implications for people with T2D and MAFLD, and the factors and interventions that modify disease progression and outcomes. The changing epidemiology of obesity and cardiovascular disease and new therapies for MAFLD on the horizon with potential implications for T2D are discussed.

Metabolic drivers of non-alcoholic fatty liver disease

BACKGROUND

The incidence of non-alcoholic fatty liver disease (NAFLD) is rapidly increasing worldwide parallel to the global obesity epidemic. NAFLD encompasses a range of liver pathologies and most often originates from metabolically driven accumulation of fat in the liver, or non-alcoholic fatty liver (NAFL). In a subset of NAFL patients, the disease can progress to non-alcoholic steatohepatitis (NASH), which is a more severe form of liver disease characterized by hepatocyte injury, inflammation, and fibrosis. Significant progress has been made over the past decade in our understanding of NASH pathogenesis, but gaps remain in our mechanistic knowledge of the precise metabolic triggers for disease worsening.

SCOPE OF REVIEW

The transition from NAFL to NASH likely involves a complex constellation of multiple factors intrinsic and extrinsic to the liver. This review focuses on early metabolic events in the establishment of NAFL and initial stages of NASH. We discuss the association of NAFL with obesity as well as the role of adipose tissue in disease progression and highlight early metabolic drivers implicated in the pathological transition from hepatic fat accumulation to steatohepatitis.

MAJOR CONCLUSIONS

The close association of NAFL with features of metabolic syndrome highlight plausible mechanistic roles for adipose tissue health and the release of lipotoxic lipids, hepatic de novo lipogenesis (DNL), and disruption of the intestinal barrier in not only the initial establishment of hepatic steatosis, but also in mediating disease progression. Human genetic variants linked to NASH risk to date are heavily biased toward genes involved in the regulation of lipid metabolism, providing compelling support for the hypothesis that NASH is fundamentally a metabolic disease.

Nonalcoholic Fatty Liver Disease in Lean Subjects: Associations With Metabolic Dysregulation and Cardiovascular Risk-A Single-Center Cross-Sectional Study

INTRODUCTION

Although a milder metabolic phenotype of nonalcoholic fatty liver disease (NAFLD) in lean patients (body mass index [BMI] <25 kg/m2) compared to overweight/obese patients with NAFLD is assumed, the relevance of NAFLD among lean subjects remains a matter of debate. We aimed to characterize the metabolic/cardiovascular phenotype of lean patients with NAFLD.

METHODS

In total, 3,043 subjects (cohort I) and 1,048 subjects (cohort II) undergoing screening colonoscopy between 2010 and 2020 without chronic liver disease other than NAFLD were assigned to one of the following groups: lean patients without NAFLD, lean NAFLD, overweight NAFLD (BMI 25-30 kg/m2), and obese NAFLD (BMI >30 kg/m2). Diagnosis of NAFLD was established using ultrasound (cohort I) and controlled attenuation parameter (cohort II).

RESULTS

The prevalence of lean patients with NAFLD was 6.7%/16.1% in the overall cohort I/II and 19.7%/40.0% in lean subjects of cohort I/II. Compared with lean subjects without NAFLD, lean patients with NAFLD had a higher prevalence of dyslipidemia, dysglycemia, and the metabolic syndrome, together with a higher median Framingham risk score in both cohorts (all P < 0.001). On multivariable analyses, NAFLD in lean subjects was associated with higher odds of metabolic syndrome (adjusted odds ratio cohort I: 4.27 [95% confidence interval (CI): 2.80-6.51], P < 0.001; cohort II: 2.97 [95% CI: 1.40-6.33], P < 0.001), and higher Framingham risk score (regression coefficient B cohort I: 1.93 [95% CI: 0.95-2.92], P < 0.003; cohort II: 1.09 [95% CI: 0.81-2.10], P = 0.034), among others. Only 69.8% of lean patients with NALFD in cohort I and 52.1% in cohort II fulfilled the novel criteria for metabolic associated fatty liver disease.

DISCUSSION

NAFLD in lean patients is associated with the metabolic syndrome and increased cardiovascular risk. Novel metabolic associated fatty liver disease criteria leave a considerable proportion of patients unclassified.