Association between body size-metabolic phenotype and nonalcoholic steatohepatitis and significant fibrosis

Global Epidemiology and Implications of PNPLA3 I148M Variant in Metabolic Dysfunction-Associated Steatotic Liver Disease: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

PNPLA3 rs738409 variant is a risk factor for onset and progression of metabolic dysfunction-associated steatotic liver disease (MASLD). We aimed to assess its global prevalence, clinical and histological characteristics, and long-term outcomes in patients with MASLD.

METHODS

PubMed and Embase databases were searched until December 30, 2023, for observational studies on PNPLA3 genotyped adults with MASLD. Proportions were pooled using a generalized linear mixed model with Clopper-Pearson intervals. Continuous and dichotomous variables were analyzed using the DerSimonian-Laird method. International Prospective Register of Systematic Reviews registration number: CRD42023449838.

RESULTS

A total of 109 studies involving 118,302 individuals with MASLD were identified. The overall minor allele frequency of the G allele [MAF(G)] at PNPLA3 was 0.45 (95% confidence interval [CI]: 0.43; 0.48) with high heterogeneity (I2 = 98%). The highest MAF(G) was found in Latin America (0.63) and the lowest in Europe (0.38). No African countries were identified. Carriers of the PNPLA3 variant had reduced adiposity, altered fat metabolism, and worse liver damage/histology than noncarriers. There was significant heterogeneity in the clinical/histological analyses (I2 > 50%). Only the PNPLA3 GG genotype was associated with higher mortality and liver-related events with no heterogeneity (I2 = 0%). Metaregressions showed the influence of adiposity, age, diabetes mellitus, and glucose on some PNPLA3 expression parameters. Overall, there was a moderate risk of bias in the included studies.

CONCLUSIONS

This study reveals the global pattern of PNPLA3 and its clinical, histological, and outcome implications in MASLD. Patients with MASLD and PNPLA3 variant have different clinical features and worse liver severity, and only PNPLA3 GG has a higher risk of mortality and liver outcomes. Our findings highlight the importance of PNPLA3 genotyping in clinical trials and advocate for personalized medicine approaches.

Genetic and Metabolic Characteristics of Lean Nonalcoholic Fatty Liver Disease in a Korean Health Examinee Cohort

Background/Aims

The pathophysiology of lean nonalcoholic fatty liver disease (NAFLD) is unclear but has been shown to be associated with more diverse pathogenic mechanisms than that of obese NAFLD. We investigated the characteristics of genetic or metabolic lean NAFLD in a health checkup cohort.

Methods

This retrospective cross-sectional study analyzed single nucleotide polymorphism data for 6,939 health examinees. Lean individuals were categorized according to a body mass index cutoff of 23 kg/m2. Single nucleotide polymorphisms were analyzed using genotyping arrays.

Results

The prevalence of lean NAFLD was 21.6% among all participants with NAFLD, and the proportion of lean NAFLD was 18.5% among lean participants. The prevalence of metabolic syndrome and diabetes among lean patients with NAFLD was 12.4% and 10.4%, respectively. Lean NAFLD appeared to be metabolic-associated in approximately 20.1% of patients. The homozygous minor allele (GG) of PNPLA3 (rs738409) and heterozygous minor alleles (CT, TT) of TM6SF2 (rs58542926) were associated with lean NAFLD. However, the prevalence of fatty liver was not associated with the genetic variants MBOAT7 (rs641738), HSD17B13 (rs72613567), MARC1 (rs2642438), or AGXT2 (rs2291702) in lean individuals. Lean NAFLD appeared to be associated with PNPLA3 or TM6SF2 genetic variation in approximately 32.1% of cases. Multivariate risk factor analysis showed that metabolic risk factors, genetic risk variants, and waist circumference were independent risk factors for lean NAFLD.

Conclusions

In a considerable number of patients, lean NAFLD did not appear to be associated with known genetic or metabolic risk factors. Further studies are required to investigate additional risk factors and gain a more comprehensive understanding of lean NAFLD.

Innovative Therapeutic Approaches in Non-Alcoholic Fatty Liver Disease: When Knowing Your Patient Is Key

Non-alcoholic fatty liver disease (NAFLD) encompasses a spectrum of disorders ranging from simple steatosis to non-alcoholic steatohepatitis (NASH). Hepatic steatosis may result from the dysfunction of multiple pathways and thus multiple molecular triggers involved in the disease have been described. The development of NASH entails the activation of inflammatory and fibrotic processes. Furthermore, NAFLD is also strongly associated with several extra-hepatic comorbidities, i.e., metabolic syndrome, type 2 diabetes mellitus, obesity, hypertension, cardiovascular disease and chronic kidney disease. Due to the heterogeneity of NAFLD presentations and the multifactorial etiology of the disease, clinical trials for NAFLD treatment are testing a wide range of interventions and drugs, with little success. Here, we propose a narrative review of the different phenotypic characteristics of NAFLD patients, whose disease may be triggered by different agents and driven along different pathophysiological pathways. Thus, correct phenotyping of NAFLD patients and personalized treatment is an innovative therapeutic approach that may lead to better therapeutic outcomes.

Comprehensive Review of Cardiovascular Disease Risk in Nonalcoholic Fatty Liver Disease

Nonalcoholic Fatty Liver Disease (NAFLD) is a growing global phenomenon, and its damaging effects in terms of cardiovascular disease (CVD) risk are becoming more apparent. NAFLD is estimated to affect around one quarter of the world population and is often comorbid with other metabolic disorders including diabetes mellitus, hypertension, coronary artery disease, and metabolic syndrome. In this review, we examine the current evidence describing the many ways that NAFLD itself increases CVD risk. We also discuss the emerging and complex biochemical relationship between NAFLD and its common comorbid conditions, and how they coalesce to increase CVD risk. With NAFLD's rising prevalence and deleterious effects on the cardiovascular system, a complete understanding of the disease must be undertaken, as well as effective strategies to prevent and treat its common comorbid conditions.

Metabolic dysfunction is associated with steatosis but no other histologic features in nonalcoholic fatty liver disease

BACKGROUND

Recently, nonalcoholic fatty liver disease (NAFLD) has been renamed metabolic-associated fatty liver disease (MAFLD). Based on the definition for MAFLD, a group of non-obese and metabolically healthy individuals with fatty liver are excluded from the newly proposed nomenclature.

AIM

To analyze the histologic features in the MAFLD and non-MAFLD subgroups of NAFLD.

METHODS

Eighty-three patients with biopsy-proven NAFLD were separated into MAFLD and non-MAFLD groups. The diagnosis of MAFLD was established as hepatic steatosis along with obesity/diabetes or evidence of metabolic dysfunction. The histologic features were compared according to different metabolic disorders and liver enzyme levels.

RESULTS

MAFLD individuals had a higher NAFLD activity score (P = 0.002) and higher severity of hepatic steatosis (42.6% Grade 1, 42.6% Grade 2, and 14.8% Grade 3 in MAFLD; 81.8% Grade 1, 13.6% Grade 2, and 4.5% Grade 3 in non-MAFLD; P = 0.007) than the non-MAFLD group. Lobular and portal inflammation, hepatic ballooning, fibrosis grade, and the presence of nonalcoholic steatohepatitis (NASH) and significant fibrosis were comparable between the two groups. The higher the liver enzyme levels, the more severe the grades of hepatic steatosis (75.0% Grade 1 and 25.0% Grade 2 in normal liver function; 56.6% Grade 1, 39.6% Grade 2, and 3.8% Grade 3 in increased liver enzyme levels; 27.8% Grade 1, 27.8% Grade 2, and 44.4% Grade 3 in liver injury; P < 0.001). Patients with liver injury (alanine aminotransferase > 3 × upper limit of normal) presented a higher severity of hepatocellular ballooning (P = 0.021). Moreover, the grade of steatosis correlated significantly with hepatocellular ballooning degree (r = 0.338, P = 0.002) and the presence of NASH (r = 0.466, P < 0.001).

CONCLUSION

Metabolic dysfunction is associated with hepatic steatosis but no other histologic features in NAFLD. Further research is needed to assess the dynamic histologic characteristics in NAFLD based on the presence or absence of metabolic disorders.

MAFLD: Renovation of clinical practice and disease awareness of fatty liver

Recently, international expert panels have proposed a new definition of fatty liver: metabolic dysfunction-associated fatty liver disease (MAFLD). MAFLD is not just a simple renaming of non-alcoholic fatty liver disease (NAFLD). The unique feature of MAFLD is the inclusion of metabolic dysfunctions, which are high-risk factors for events. In addition, MAFLD is independent of alcohol intake and the co-existing causes of liver disease. This new concept of MAFLD may have a widespread impact on patients, medical doctors, medical staff, and various stakeholders regarding fatty liver. Thus, MAFLD may renovate clinical practice and disease awareness of fatty liver. In this review, we introduce the definition of and rationale for MAFLD. We further describe representative cases showing how the diagnostic processes differ between MAFLD and NAFLD. We also summarize recent studies comparing MAFLD with NAFLD and discuss the impact of MAFLD on clinical trials, Japanese populations, and disease awareness.

MAFLD enhances clinical practice for liver disease in the Asia-Pacific region

Fatty liver is now a major cause of liver disease in the Asia-Pacific region. Liver diseases in this region have distinctive characteristics. First, fatty liver is frequently observed in lean/normal-weight individuals. However, there is no standard definition of this unique phenotype. Second, fatty liver is often observed in patients with concomitant viral hepatitis. The exclusion of viral hepatitis from non-alcoholic fatty liver disease limits its value and detracts from the investigation and holistic management of coexisting fatty liver in patients with viral hepatitis. Third, fatty liver-associated hepatocellular carcinoma (HCC) is generally categorized as non-B non-C HCC. Fourth, the population is aging rapidly, and it is imperative to develop a practicable, low-intensity exercise program for elderly patients. Fifth, most patients and nonspecialized healthcare professionals still lack an awareness of the significance of fatty liver both in terms of intrahepatic and extrahepatic disease and cancer. Recently, an international expert panel proposed a new definition of fatty liver: metabolic dysfunction-associated fatty liver disease (MAFLD). One feature of MAFLD is that metabolic dysfunction is a prerequisite for diagnosis. Pertinent to regional issues, MAFLD also provides its diagnostic criteria in lean/normal-weight individuals. Furthermore, MAFLD is independent of any concomitant liver disease, including viral hepatitis. Therefore, MAFLD may be a more suitable definition for fatty liver in the Asia-Pacific region. In this review, we introduce the regional characteristics of fatty liver and discuss the advantages of MAFLD for improving clinical practice for liver disease in the region.

Association of genetic variations with NAFLD in lean individuals

BACKGROUND & AIMS

How adiposity influences the effect of genetic variants on non-alcoholic fatty liver disease (NAFLD) in the Asian population remains unclear. We aimed to study the association between genetic risk variants and susceptibility/severity of NAFLD in the lean, overweight and obese individuals.

METHODS

Nine hundred and four community subjects underwent proton-magnetic resonance spectroscopy and transient elastography examination. Lean (<23 kg/m2 ), overweight (23-24.9 kg/m2 ) and obesity (≥25 kg/m2 ) were defined according to the body mass index cut-offs for Asians. NAFLD was defined as intrahepatic triglycerides ≥5%. PNPLA3, TM6SF2, MBOAT7 and 9 other gene polymorphisms were analysed by rhAMPTM SNP assays.

RESULTS

Five hundred and twenty-nine (58.5%), 162 (17.9%) and 213 (23.6%) subjects were lean, overweight and obese, respectively. The prevalence of NAFLD was 12.4%, 41.4% and 59.1% in the three groups (P < .001). Amongst those with NAFLD, lean subjects (30.3%) were more likely to carry the PNPLA3 rs738409 GG genotype than overweight (17.9%) and obese subjects (17.4%) (P = .003). Compared with the CC genotype, the GG genotype was associated with the greatest increase in the risk of NAFLD in lean subjects (odds ratio [OR] 6.04), compared with overweight (OR 3.43, 95% CI [1.06, 11.14]) and obese subjects (OR 2.51, 95% CI [0.93, 6.78]). Additionally, the TM6SF2 rs58542926 TT genotype was associated with reduced serum triglycerides only in lean subjects. A gene-BMI effect was not observed for the other gene polymorphisms.

CONCLUSIONS

The PNPLA3 rs738409 gene polymorphism has a greater effect on liver fat in Asian lean individuals than in overweight or obese ones.

Weight change and resolution of fatty liver in normal weight individuals with nonalcoholic fatty liver disease

OBJECTIVES

Obesity is a well-known risk factor for nonalcoholic fatty liver disease (NAFLD), and weight reduction is primarily recommended for managing the disease. However, some NAFLD patients have a normal weight (lean NAFLD), and whether weight reduction is also recommendable for lean NAFLD patients remains unclear.

METHODS

We conducted a longitudinal study of 16 738 adults (average age, 50.5 years; lean NAFLD, 2383 participants) with NAFLD at baseline who underwent repeated health check-up examinations, including bodyweight measurements and abdominal ultrasonography from January 2003 through December 2013.

RESULTS

During 68 389 person-years of follow-up (median follow-up of 3.00 years), 5819 patients had a fatty liver resolution. Compared with participants who had no weight reduction or increased weight, the fully adjusted hazard ratios for fatty liver resolution in participants with 0-4.9, 5-9.9 and 10% or more weight reduction were 1.67 [95% confidence interval (CI), 1.57-1.77], 3.36 (95% CI, 3.09-3.65) and 5.50 (95% CI, 4.83-6.27), respectively. The association between weight reduction and the fatty liver resolution was stronger in overweight/obese NAFLD participants but was also evident in lean NAFLD participants in a dose-dependent manner. In spline regression models, the association between weight change and the fatty liver resolution was linear among participants with normal weight.

CONCLUSION

There was a dose-dependent association between weight reduction and fatty liver resolution in both lean and overweight/obese NAFLD patients. This finding suggests weight reduction as a primary recommendation for lean NAFLD patients as in overweight/obese NAFLD patients.

High frequency and long persistency of ballooning hepatocyte were associated with glucose intolerance in patients with severe obesity

Nonalcoholic steatohepatitis (NASH) and glucose intolerance are associated with an increased risk of mortality in patients with severe obesity; however, whether histological findings of the liver are related to glucose intolerance in these patients remain unknown. Sixty-nine consecutive patients who underwent metabolic surgery between June 2008 and February 2020 were included; histological findings of the liver and laboratory data were analyzed. Twenty patients with biopsy-proven NASH were chronologically evaluated using sequential biopsies; data before metabolic surgery was considered as the baseline. Glucose intolerance—demonstrated by an increased area under the curve (AUC) for blood sugar (BS) during the 75-g oral glucose tolerance test—and increased homeostatic model assessment for insulin resistance (HOMA-IR) correlated with the grade of hepatocyte ballooning in patients. Patients with persistent ballooning at the follow-up biopsy had a higher HOMA-IR, high AUC for BS, and lower adiponectin level than those in patients in whom ballooning was eliminated, while there was no significant difference in body weight. We concluded that glucose intolerance was associated with the grade of hepatocyte ballooning; additionally, persistent hepatocyte ballooning sustained glucose intolerance, while elimination of hepatocyte ballooning improved the condition. Glucose intolerance may, thus, mediate balloon formation of the hepatocyte.

Development of a novel mouse model of diet-induced nonalcoholic steatohepatitis-related progressive bridging fibrosis

Nonalcoholic steatohepatitis (NASH) progresses to liver fibrosis and cirrhosis. Existing mouse models of NASH rarely develop diet-induced severe fibrosis. We aimed to establish a dietary model of NASH with rapid progression to fibrosis. Six-week-old male Tsumura-Suzuki obese diabetes (TSOD) mice (a model of spontaneous metabolic syndrome) and corresponding control Tsumura-Suzuki nonobese (TSNO) mice were fed a novel diet high in fat, cholesterol, and cholate (iHFC). Histologic steatohepatitis, including steatosis, inflammation, and fibrosis, were observed in both TSNO and TSOD iHFC diet-fed mice at 20 weeks of age. As compared with TSOD mice, TSNO mice developed much more severe fibrosis and reached stage 3 of bridging fibrosis within 14 weeks under the iHFC diet feeding. Perivenular/perisinusoidal pattern of fibrosis in TSNO mice resembled human NASH. Our model of NASH with advanced fibrosis by simple diet offers many advantages useful in studying the mechanism of liver fibrosis and preclinical drug testing.

White Adipose Tissue Autophagy and Adipose-Liver Crosstalk Exacerbate Nonalcoholic Fatty Liver Disease in Mice

BACKGROUND & AIMS

Although nonalcoholic fatty liver disease (NAFLD) is closely associated with obesity, the role of adipose tissue in NAFLD is not well-understood. Because autophagy has been reported to be involved in the degradation of lipid droplets, we investigated the role of adipose tissue autophagy in the liver pathogenesis of NAFLD.

METHODS

C57BL/6J mice and adipocyte-specific Atg7-knockout mice (Adipoq-Atg7 KO mice) were fed a high-fat diet (HFD).

RESULTS

HFD feeding for up to 4 months increased both inguinal and epididymal white adipose tissue (iWAT and eWAT, respectively; the former represents subcutaneous fat, and the latter represents visceral fat) in mice. After HFD feeding, autophagy flux in both types of white adipose tissue was increased, and the levels of Rubicon, a negative autophagy regulator, were decreased, suggesting autophagy promotion. Adipoq-Atg7 KO mice exhibited suppressed autophagy in both iWAT and eWAT. Adipocyte-specific Atg7 KO enhanced HFD-induced iWAT hypertrophy. On the other hand, eWAT levels in Adipoq-Atg7 KO mice were increased after 1 month of HFD feeding but decreased after 4 months of HFD feeding compared with those in wild-type controls. Cleaved caspase 3 and JNK pathway protein expression in eWAT was increased without cytokine elevation in Adipoq-Atg7 KO mice fed an HFD compared with wild-type mice fed an HFD. Adipocyte-specific Atg7 KO decreased serum free fatty acid levels and ameliorated HFD-induced steatosis, liver inflammation, and fibrosis.

CONCLUSIONS

Autophagy was enhanced in the white adipose tissues of mice fed an HFD. Autophagy inhibition in white adipose tissues ameliorated the liver pathology of NAFLD via adipose-liver crosstalk.

Recent Epidemiology of Nonalcoholic Fatty Liver Disease

The ongoing obesity epidemic and the increasing recognition of metabolic syndrome have contributed to the growing prevalence of nonalcoholic fatty liver disease (NAFLD), the most common form of liver disease worldwide. It is imperative to understand the incidence and prevalence of NAFLD as it is associated with a profound economic burden of hospitalizations, including the shifting trends in liver transplantation. The long-term cumulative healthcare cost of NAFLD patients has been shown to be 80% higher than that of non-NAFLD patients. We explore diagnostic challenges in identifying those with NAFLD who have a higher predilection to progress to end-stage liver disease. We aim to assess all-cause and cause-specific mortality as it relates to NAFLD.

Shifting perspectives - interplay between non-alcoholic fatty liver disease and insulin resistance in lean individuals

Non-alcoholic fatty liver disease (NAFLD) has become a significant public health burden affecting not only obese individuals but also people with normal weight. As opposed to previous beliefs, this particular subset of patients has an increased risk of all-cause mortality and worse outcomes than their obese counterparts. The development of NAFLD in lean subjects seems to be interconnected with metabolic phenotype, precisely visceral fat tissue, sarcopenia, and insulin resistance. Here, we summarize available data focusing on the co-dependent relationship between metabolic phenotype, insulin resistance, and development of NAFLD in lean individuals, suggesting more appropriate tools for measuring body fat distribution for the screening of patients at risk.

Association of arterial stiffness with the histological severity of nonalcoholic fatty liver disease

BACKGROUND

Although arterial stiffness has been reported to be associated with nonalcoholic fatty liver disease (NAFLD), previous studies have relied only on noninvasive assessments for the diagnosis of NAFLD. This study attempted to investigate the association of arterial stiffness with the histological severity of NAFLD.

METHODS

We analyzed data from a biopsy-proven prospective NAFLD cohort. Augmentation index corrected for a heart rate of 75 bpm (AI@75) was obtained using applanation tonometry of the radial artery.

RESULTS

A total of 154 patients (mean age 55.2 years; females 55.8%) with biopsy-proven NAFLD were analyzed. Patients with higher AI@75 (≥ 76%) showed more severe grades of lobular and portal inflammation and hepatocellular ballooning, and more advanced stages of fibrosis compared to those with lower AI@75 (< 76%) (p < 0.05 for each). The presence of nonalcoholic steatohepatitis (NASH) (adjusted odds ratio [aOR] 2.48; 95% confidence interval [CI] 1.31-6.16; p = 0.008), lobular inflammation (aOR 2.03; 95% CI 1.09-3.78; p = 0.025) hepatocellular ballooning (aOR 2.82; 95% CI 1.23-6.43; p = 0.014), and significant fibrosis (≥ F2) (aOR 3.42; 95% CI 1.50-7.79; p = 0.003) were independently associated with higher AI@75 (≥ 76%) even after adjustment for confounders.

CONCLUSION

Arterial stiffness as indicated by higher AI@75 was associated with more severe NAFLD histology. This adds to the evidence for the association between increased arterial stiffness and NAFLD.

MAFLD identifies patients with significant hepatic fibrosis better than NAFLD

BACKGROUND & AIMS

Diagnostic criteria for metabolic associated fatty liver disease (MAFLD) have been proposed, but not validated. We aimed to compare the diagnostic accuracy of the MAFLD definition vs the existing NAFLD criteria to identify patients with significant fibrosis and to characterize the impact of mild alcohol intake.

METHODS

We enrolled 765 Japanese patients with fatty liver (median age 54 years). MAFLD and NAFLD were diagnosed in 79.6% and 70.7% of patients respectively. Significant fibrosis was defined by FIB-4 index ≥1.3 and liver stiffness ≥6.6 kPa using shear wave elastography. Mild alcohol intake was defined as <20 g/day. Factors associated with significant fibrosis were analysed by logistic regression and decision-tree analyses.

RESULTS

Liver stiffness was higher in MAFLD compared to NAFLD (7.7 vs 6.8 kPa, P = .0010). In logistic regression, MAFLD (OR 4.401; 95% CI 2.144-10.629; P < .0001), alcohol intake (OR 1.761; 95% CI 1.081-2.853; P = .0234), and NAFLD (OR 1.721; 95%CI 1.009-2.951; P = .0463) were independently associated with significant fibrosis. By decision-tree analysis, MAFLD, but not NAFLD or alcohol consumption was the initial classifier for significant fibrosis. The sensitivity for detecting significant fibrosis was higher for MAFLD than NAFLD (93.9% vs 73.0%). In patients with MAFLD, even mild alcohol intake was associated with an increase in the prevalence of significant fibrosis (25.0% vs 15.5%; P = .0181).

CONCLUSIONS

The MAFLD definition better identifies a group with fatty liver and significant fibrosis evaluated by non-invasive tests. Moreover, in patients with MAFLD, even mild alcohol consumption is associated with worsening of hepatic fibrosis measures.

Circulating lipidomic alterations in obese and non-obese subjects with non-alcoholic fatty liver disease

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) affects obese and non-obese individuals. However, mechanisms underlying non-obese non-alcoholic steatohepatitis (NASH) remain unclear.

AIMS

To attempt to identify metabolic perturbations associated with non-obese and obese NAFLD using a lipidomics approach.

METHODS

A cross-sectional analysis of 361 subjects with biopsy-proven NAFLD (157 NAFL and 138 NASH) and healthy controls (n = 66) was performed. Individuals were categorised as obese or non-obese based on the Asian cut-off for body mass index. Circulating lipidomic profiling of sera was performed based on the histological severity of NAFLD. Circulating lipidomic alterations were validated with an independent validation set (154 NAFLD subjects [93 NAFL and 61 NASH] and 21 healthy controls).

RESULTS

Saturated sphingomyelin (SM) species were significantly associated with visceral adiposity in non-obese NAFLD (SM d38:0; P < 0.001) but not in obese NAFLD. Additionally, SM levels were significantly associated with systemic and adipose tissue insulin resistance (SM d38:0; P = 0.002 and <0.001, respectively). Five potential lipid metabolites for non-obese subjects and seven potential lipids for obese subjects were selected to predict NAFLD and NASH. These lipid combinations showed good diagnostic performance for non-obese (area under the curve [AUC] for NAFLD/NASH = 0.916/0.813) and obese (AUC for NAFLD/NASH = 0.967/0.812) subjects. Moreover, distinctly altered patterns of diacylglycerol (DAG), triacylglycerol (TAG) and SM levels were confirmed in the validation set depending on the histological severity of NAFLD.

CONCLUSION

Non-obese and obese NAFLD subjects exhibit unique circulating lipidomic signatures, including DAGs, TAGs and SMs. These lipid combinations may be useful biomarkers for non-obese and obese NAFLD patients.

Development and validation of a novel non-invasive test for diagnosing fibrotic non-alcoholic steatohepatitis in patients with biopsy-proven non-alcoholic fatty liver disease

BACKGROUND AND AIM

There is an immediate need for non-invasive accurate tests for diagnosing liver fibrosis in patients with non-alcoholic steatohepatitis (NASH). Previously, it has been suggested that MACK-3 (a formula that combines homeostasis model assessment-insulin resistance with serum serum aspartate aminotransferase and cytokeratin [CK]18-M30 levels) accurately identifies patients with fibrotic NASH. Our aim was to assess the performance of MACK-3 and develop a novel, non-invasive algorithm for diagnosing fibrotic NASH.

METHODS

Six hundred and thirty-six adults with biopsy-proven non-alcoholic fatty liver disease (NAFLD) from two independent Asian cohorts were enrolled in our study. Liver stiffness measurement (LSM) was assessed by vibration-controlled transient elastography (Fibroscan). Fibrotic NASH was defined as NASH with a NAFLD activity score (NAS) ≥ 4 and F ≥ 2 fibrosis.

RESULTS

Metabolic syndrome (MetS), platelet count and MACK-3 were independent predictors of fibrotic NASH. On the basis of their regression coefficients, we developed a novel nomogram showing a good discriminatory ability (area under receiver operating characteristic curve [AUROC]: 0.79, 95% confidence interval [CI 0.75-0.83]) and a high negative predictive value (NPV: 94.7%) to rule out fibrotic NASH. In the validation set, this nomogram had a higher AUROC (0.81, 95%CI 0.74-0.87) than that of MACK-3 (AUROC: 0.75, 95%CI 0.68-0.82; P < 0.05) with a NPV of 93.2%. The sequential combination of this nomogram with LSM data avoided the need for liver biopsy in 56.9% of patients.

CONCLUSIONS

Our novel nomogram (combining MACK-3, platelet count and MetS) shows promising utility for diagnosing fibrotic NASH. The sequential combination of this nomogram and vibration-controlled transient elastography limits indeterminate results and reduces the number of unnecessary liver biopsies.