Are the different MAFLD subtypes based on the inclusion criteria correlated with all-cause mortality?

The Global Epidemic of Metabolic Fatty Liver Disease

PURPOSE OF REVIEW

The objective of this manuscript is to examine the current literature on the epidemiology of metabolic dysfunction-associated steatotic liver disease (MASLD), its correlation with cardiovascular disease (CVD) outcomes, as well as to evaluate the update in nomenclature from non-alcoholic liver disease (NAFLD).

RECENT FINDINGS

The update of diagnostic criteria from NAFLD to MASLD reduces the stigma associated with alcohol consumption and poor health choices. It also shines a light on the crucial role of cardiometabolic risk factors in disease pathophysiology. The incidence and prevalence of MASLD are projected to increase significantly in the future as the population burden of cardiometabolic risk factors rises. MASLD is also a potent risk factor for developing CVD that should be tackled by using a multi-disciplinary team with a holistic approach. As the new nomenclature for metabolic liver disease is adopted on a global scale, more research is needed to investigate the applicability of findings from previous trials focusing on NAFLD. It is anticipated that the epidemic of MASLD will continue to increase globally, hence the urgent need for therapeutic approaches to reverse this trend.

Association of Stroke With Metabolic Dysfunction-Associated Fatty Liver Disease With and Without CKD

RATIONALE & OBJECTIVE

Metabolic dysfunction-associated fatty liver disease (MAFLD), a risk factor for stroke and all-cause mortality, is highly prevalent among patients with chronic kidney disease (CKD), but it is unclear whether the association of MAFLD with stroke and all-cause mortality differs within and outside of the setting of CKD.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

We enrolled 95,353 participants from the Kailuan Cohort Study, among whom 35,749 had CKD at baseline or developed CKD during the follow-up period, and 59,604 individuals who had no CKD at baseline or during the follow-up period.

EXPOSURE

MAFLD.

OUTCOME

Stroke (ischemic stroke, hemorrhagic stroke), all-cause mortality.

ANALYTICAL APPROACH

Adjusted Cox regression models were used to estimate the influence of MAFLD on stroke outcomes within the subgroups defined by the presence of CKD.

RESULTS

After a median follow-up of 12.8 years, 6,140 strokes (6.4%) and 11,975 deaths from any cause (12.6%) occurred. After adjusting for potential confounders, MAFLD was associated with an increased incidence of stroke among the participants with CKD (HR, 1.34 [95% CI, 1.23-1.45]) but not among those without CKD (HR, 1.05 [95% CI, 0.97-1.15]; Pinteraction<0.001). This association was principally related to ischemic stroke (HR, 1.38 [95% CI, 1.26-1.51]) and not hemorrhagic stroke (HR, 1.04 [95% CI, 0.85-1.26]). No association was found between MAFLD and all-cause mortality in the participants with CKD (HR,1.04 [95% CI, 0.98-1.10]) or those without CKD (HR,1.03 [95% CI, 0.97-1.09]). Among the participants with CKD, compared with non-MAFLD, MAFLD with diabetes (HR,1.36 [95% CI, 1.23-1.50]) or overweight/obesity (HR,1.30 [95% CI, 1.14-1.50]) was associated with a higher risk of stroke whereas MAFLD without overweight/obesity or diabetes was not associated with a higher risk (HR,1.08 [95% CI, 0.81-1.43]).

LIMITATIONS

This was an observational study and included individuals with CKD who had a relatively high estimated glomerular filtration rate.

CONCLUSIONS

MAFLD was associated with an increased risk of stroke in individuals with CKD but not in those without CKD.

PLAIN-LANGUAGE SUMMARY

Metabolic dysfunction-associated fatty liver disease (MAFLD), which is recognized as a risk factor for stroke in the general population, is highly prevalent among individuals with chronic kidney disease (CKD). However, the impact of MAFLD on the risk of stroke in patients with CKD remains uncertain. We investigated the association of MAFLD with stroke in individuals with and without CKD. Our analysis revealed that MAFLD was associated with a significantly increased risk of stroke in individuals with CKD, and the magnitude of this increased risk was greater in the setting of CKD. These findings highlight the need for increased attention to MAFLD in patients with CKD and emphasize that addressing and preventing MAFLD in this population may contribute to reduced morbidity from stroke.

Comparative associations of MASLD and MAFLD with the presence and severity of coronary artery calcification

We aimed to compare the associations of metabolic dysfunction-associated steatotic liver disease (MASLD) and metabolic dysfunction-associated fatty liver disease (MAFLD) with coronary artery calcification (CAC). Patients who simultaneously underwent ultrasonography to diagnose hepatic steatosis and cardiac computed tomography to detect CAC were included. The presence and severity of CAC were defined with CAC-score thresholds of >0 and > 300, respectively, and patients were divided into the following groups: no MASLD or MAFLD (reference), MASLD-only, MAFLD-only, and overlapping groups. Overall, 1,060/2,773 (38.2%) patients had CAC, of which 196 (18.5%) had severe CAC. The MASLD and MAFLD prevalence rates were 32.6% and 45.2%, respectively, with an overlap of 30.7%. In an ASCVD risk score-adjusted model, both MASLD (adjusted odd ratios [aOR], 1.21; 95% confidence interval [CI], 1.02-1.44; p = 0.033) and MAFLD (aOR, 1.20; 95% CI, 1.01-1.42, p = 0.034) were associated with CAC, whereas only MASLD (aOR, 1.38; 95% CI, 1.01-1.89, p = 0.041) was associated with severe CAC. Compared to the reference group, the overlapping group showed an association with CAC (aOR, 1.22; 95% CI, 1.01-1.47; p = 0.038); however, the MASLD and MAFLD subgroups did not differ in their association with CAC. MASLD may predict a higher risk of ASCVD more effectively than MAFLD.

Metabolic puzzle: Exploring liver fibrosis differences in Asian metabolic-associated fatty liver disease subtypes

BACKGROUND

Metabolic-associated fatty liver disease (MAFLD) is a liver condition marked by excessive fat buildup in the absence of heavy alcohol use. It is primarily linked with metabolic issues like insulin resistance, obesity, and abnormal lipid levels, and is often observed with other conditions such as type 2 diabetes and cardiovascular disease. However, whether the subtypes of MAFLD based on the metabolic disorder differentially impact liver fibrosis is not well explicated, especially in the Asian population.

AIM

To compare the severity of liver fibrosis among different MAFLD subtypes.

METHODS

A total of 322 adult patients of either gender with fatty liver on ultrasound were enrolled between January to December 2021. MAFLD was defined as per the Asian Pacific Association for the Study of the Liver guidelines. Fibrosis-4 index (Fib-4) and nonalcoholic fatty liver disease fibrosis score (NFS) were employed to evaluate liver fibrosis.

RESULTS

The mean age was 44.84 ± 11 years. Seventy-two percent of the patients were female. Two hundred and seventy-three patients were classified as having MAFLD, of which 110 (40.3%) carried a single, 129 (47.3%) had two, and 34 (12.5%) had all three metabolic conditions. The cumulative number of metabolic conditions was related to elevated body mass index, triglyceride (TG) levels, and glycated hemoglobin, lower high-density lipoprotein (HDL) levels, higher liver inflammation (by aspartate aminotransferase and γ-glutamyl transferase), and higher likelihood of fibrosis (by NFS and Fib-4 scores) (P < 0.05 for all). The proportion of advanced fibrosis also increased with an increase in the number of metabolic conditions (4.1%, 25.5%, 35.6%, and 44.1% by NFS and 6.1%, 10.9%, 17%, and 26.5% by Fib-4 for no MAFLD and MAFLD with 1, 2, and 3 conditions, respectively). Among MAFLD patients, those with diabetes alone were the eldest and had the highest mean value of NFS score and Fib-4 score (P < 0.05), while MAFLD patients diagnosed with lean metabolic dysfunction exhibited the highest levels of TG and alanine aminotransferase but the lowest HDL levels (P < 0.05).

CONCLUSION

The study suggests that the severity of liver fibrosis in MAFLD patients is influenced by the number and type of metabolic conditions present. Early identification and management of MAFLD, particularly in patients with multiple metabolic conditions, are crucial to prevent liver-related complications.

Intra-gastric balloon with lifestyle modification: a promising therapeutic option for overweight and obese patients with metabolic dysfunction-associated steatotic liver disease

BACKGROUND

Data on effects of intra-gastric balloon (IGB) on metabolic dysfunction-associated steatotic liver disease (MASLD) are scarce, in part with contradictory results, and mainly obtained in tertiary care patients with diabetes and other comorbidities. We here explore effects of IGB in patients with MASLD referred to a first-line obesity clinic.

METHODS

In this prospective cohort study, patients with at least significant fibrosis (≥ F2) and/or severe steatosis (S3) according to screening transient elastography (FibroScan®) were offered a second FibroScan® after 6 months lifestyle modification with or without IGB (based on patient preference).

RESULTS

50 of 100 consecutively screened patients (generally non-diabetic) qualified for repeated evaluation and 29 (58%) of those had a second FibroScan®. At baseline, at least significant fibrosis was present in 28% and severe steatosis in 91%. IGB was placed in 19 patients (59%), whereas 10 patients (41%) preferred only lifestyle modification (no differences in baseline characteristics between both groups). After 6 months, liver stiffness decreased markedly in the IGB group (median: from 6.0 to 4.9 kPa, p = 0.005), but not in the lifestyle modification only group (median: from 5.5 to 6.9 kPa, p = 0.477). Steatosis improved in both groups, (controlled attenuation parameter values; IGB, mean ± SD: from 328 ± 34 to 272 ± 62 dB/m, p = 0.006: lifestyle modification only, mean ± SD: from 344 ± 33 to 305 ± 43 dB/m: p = 0.006).

CONCLUSION

Both steatosis and fibrosis improve markedly in overweight/obese patients with MASLD after 6 months IGB combined with lifestyle modification. Our results warrant further research into long-term effect of IGB in these patients.

Diabetic MAFLD is associated with increased risk of hepatocellular carcinoma and mortality in chronic viral hepatitis patients

Metabolic dysfunction-associated fatty liver disease (MAFLD) can coexist with chronic viral hepatitis. MAFLD is a heterogeneous disease because the diagnostic criteria include various metabolic traits. We aimed to identify patients at high risk of poor long-term outcomes based on MAFLD subgroups in chronic viral hepatitis patients. We evaluated 63 273 chronic hepatitis B and C patients. Patient with a fatty liver index ≥30 was defined to have hepatic steatosis. MAFLD was defined as the presence of hepatic steatosis with any one of the following three conditions, overweight/obesity, type 2 diabetes or ≥2 metabolic risk factors. The prevalence of MAFLD was 38.4% (n = 24 290). During a median 8.8-year follow-up, 1839 HCCs and 2258 deaths were documented in MAFLD patients. Among MAFLD patients, diabetes could identify patients at high risk of HCC and mortality, whereas overweight/obesity and metabolic risk factors did not. Compared with non-MAFLD patients, risk of HCC and mortality was significantly higher in diabetic MAFLD patients (adjusted hazard ratio [aHR] = 1.34, 95% confidence interval [CI] = 1.26-1.43 for HCC; aHR = 1.15, 95% CI = 1.08-1.22 for mortality). Risk of HCC and mortality was significantly higher in diabetic MAFLD patients (aHR = 1.40, 95% CI = 1.26-1.55 for HCC; aHR = 1.77, 95% CI = 1.63-1.93 for mortality) compared with non-diabetic MAFLD patients. Diabetic MAFLD is associated with increased risk of HCC and mortality among chronic viral hepatitis patients. Our findings highlight the need for close surveillance and effective treatment for these high-risk patients to reduce HCC and mortality in patients with chronic viral hepatitis.

A simpler definition of MAFLD precisely predicts incident metabolic diseases: a 7-year cohort study

BACKGROUND

Metabolic dysfunction-associated fatty liver disease (MAFLD) is a novel definition proposed in 2020 with a relatively complex set of criteria. Thus, simplified criteria that are more applicable are required. This study aimed to develop a simplified set of criteria for identifying MAFLD and predicting MAFLD-related metabolic diseases.

METHODS

We developed a simplified set of metabolic syndrome-based criteria for MAFLD, and compared the performance of the simplified criteria with that of the original criteria in predicting MAFLD-related metabolic diseases in a 7-year follow-up.

RESULTS

In the 7-year cohort, a total of 13,786 participants, including 3372 (24.5%) with fatty liver, were enrolled at baseline. Of the 3372 participants with fatty liver, 3199 (94.7%) met the MAFLD-original criteria, 2733 (81.0%) met the simplified criteria, and 164 (4.9%) were metabolic healthy and met neither of the criteria. During 13,612 person-years of follow-up, 431 (16.0%) fatty liver individuals newly developed T2DM, with an incidence rate of 31.7 per 1000 person-years. Participants who met the simplified criteria had a higher risk of incident T2DM than those who met the original criteria. Similar results were observed for incident hypertension, and incident carotid atherosclerotic plaque.

CONCLUSION

The MAFLD-simplified criteria are an optimized risk stratification tool for predicting metabolic diseases in fatty liver individuals.

Associations of MAFLD and MAFLD subtypes with the risk of the incident myocardial infarction and stroke

Metabolic dysfunction-associated fatty liver disease (MAFLD) is a condition characterized by liver fat accumulation and metabolic abnormalities. Given the potential impact of MAFLD on patient health, it is important to understand its association with major adverse cardiovascular events (MACE) such as myocardial infarction (MI) and stroke. In the prospective UK Biobank cohort, we sought to elucidate the association of MAFLD and its subtypes with incident MI and stroke. In this study, we analyzed the data of 325,129 participants in the UK Biobank and calculated relative risks for MI and stroke using Cox regression analysis. Among 325,129 participants over a median duration of 12.8 years follow-up, participants with MAFLD were significantly more likely to experience a MI (hazard ratio [HR] = 1.35, 95% confidence interval [CI: 1.29;1.41] P < 0.001) or a stroke (HR = 1.26 [1.18-1.33] P < 0.001) compared to those without MAFLD. In addition, diabetic, overweight with metabolic dysfunction (MD), and lean MAFLD subtypes were significantly associated with an increased risk for MI and stroke, whereas overweight without MD subtype did not appear to be associated with this risk. Our findings also revealed graded associations between liver fibrosis scores and risk of MI and stroke in MAFLD patients. However, only diabetic, and overweight patients with MD subtypes exhibited graded associations between liver fibrosis score and the risk of MI and stroke among the MAFLD subtypes. Furthermore, the risk alleles traits of fatty liver did not enhance the effect of MAFLD on the risk of MI and stroke. In conclusion, a diagnosis of MAFLD is associated with an increased risk of MI or stroke, and the assessment of MAFLD and its subtypes should be a component of the cardiovascular risk assessment.

Lean Metabolic-Associated Fatty Liver Disease

Since the nomenclature change from nonalcoholic fatty liver disease (NAFLD) to metabolic-associated fatty liver disease (MAFLD), much work has been undertaken to establish the clinical characteristics as well as the hepatic and extrahepatic complications of the different MAFLD subtypes. Currently, there has been significant work performed to evaluate previously acknowledged evidence in the lean NAFLD population to determine its applicability to the new entity. This article examines recently published data on lean MAFLD cohorts to highlight the prevalence, pathophysiological characteristics, associated liver fibrosis, genetics, hepatic and extrahepatic complications, prognosis, treatment, and research into this unique subtype of MAFLD.

The Spectrum and Impact of Metabolic Dysfunction in MAFLD: A Longitudinal Cohort Analysis of 32,683 Overweight and Obese Individuals

BACKGROUND

Metabolic associated fatty liver disease (MAFLD) was recently proposed as an alternative name change for better encapsulation of disease. However, there exists a spectrum of MAFLD where both metabolically healthy (MH) and metabolically unhealthy (MU) individuals are included. In view of limited evidence, we sought to examine the prevalence, clinical characteristics, and differences in outcomes of MH-MAFLD at the population level.

METHODS

Data were used from the United States National Health and Nutrition Examination Survey 1999 to 2018. Multivariate logistic regression analysis was used to obtain odds ratios for the estimation of events. Survival analysis was conducted with Cox regression and the Fine-Gray subdistribution model.

RESULTS

There were 32,683 overweight and obese individuals included in the analysis. In MAFLD patients, the prevalence of MH-MAFLD was 6.92% (95% confidence interval [CI], 6.58%-7.27%), and 93.08% (95% CI, 92.73%-93.42%) were considered as MU-MAFLD. Multivariate analysis found a significantly higher risk of MACE (odds ratio, 1.38; 95% CI, 1.28-1.49; P < .01), all-cause (hazard ratio, 1.24; 95% CI, 1.17-1.32; P < .01), cardiovascular disease (SHR, 1.20; 95% CI, 1.02-1.42; P = .03), and cancer mortality (SHR, 1.24; 95% CI, 1.07-1.44; P < .01) in MU-MAFLD relative to non-MAFLD. However, MH-MAFLD individuals were not associated with a statistically significant increased risk of these adverse outcomes compared with non-MAFLD. MU-MAFLD diabetics were also at a higher risk of adverse events compared with non-diabetics.

CONCLUSIONS

This study reports on the heterogeneity and spectrum of metabolic dysfunction that exists in overweight and obese MAFLD. Although MAFLD may potentially be advantageous in improving awareness and patient outcomes, there remains substantial heterogeneity within patients included in MAFLD on the basis of the underlying metabolic burden.

Long-term clinical outcomes of adults with metabolic dysfunction-associated fatty liver disease: a single-centre prospective cohort study with baseline liver biopsy

BACKGROUND

There are limited data on the long-term adverse clinical outcomes of adults with metabolic dysfunction-associated fatty liver disease (MAFLD).

METHODS

This is a single-centre prospective study of a well-characterized cohort of MAFLD patients who underwent liver biopsy and followed every 6-12 months for adverse clinical outcomes.

RESULTS

The data for 202 patients were analyzed [median age 55.0 (48.0-61.3) years old; male, 47.5%; obese, 88.6%; diabetes mellitus, 71.3%; steatohepatitis, 76.7%; advanced fibrosis, 27.2%]. The median follow-up interval was 7 (4-8) years. The cumulative incidence of liver-related events, cardiovascular events, malignancy and mortality was 0.43, 2.03, 0.60 and 0.60 per 100 person-years of follow-up, respectively. Liver-related events were only seen in patient with advanced fibrosis at 9.1% vs 0% in patient without advanced liver fibrosis (p < 0.001). The cumulative incidence of liver-related events among patients with advanced fibrosis was 1.67 per 100 person-years of follow-up. When further stratified to bridging fibrosis and cirrhosis, the cumulative incidence of liver-related events was 1.47 and 3.85 per 100 person-years of follow-up, respectively. Advanced fibrosis was not significantly associated with cardiovascular events, malignancy or mortality. The cumulative incidence of liver-related events, cardiovascular events, malignancy and mortality were not significantly different between patients with and without steatohepatitis and between obese and non-obese patients. However, liver-related events were only seen among obese patients.

CONCLUSION

Overall, the cumulative incidence of liver-related event is low in patients with MAFLD, but it is much higher among those with advanced fibrosis. However, there is a relatively high cumulative incidence of cardiovascular event among patients with MAFLD.

The association between thyroid hormones and MAFLD is mediated by obesity and metabolic disorders and varies among MAFLD subtypes

BACKGROUND

Thyroid hormone (TH) disorders increased the risk of metabolic dysfunction-associated fatty liver disease (MAFLD).

AIM

To assess whether the association between TH and MAFLD is mediated via metabolic dysfunctions and varies among MAFLD subtypes (diabetes-MAFLD, overweight/obesity-MAFLD, metabolic disorders-MAFLD).

METHODS

A total of 18,427 participants (661 diabetes-MAFLD, 3,600 overweight/obesity-MAFLD, 691 metabolic disorder-MAFLD cases, 13,475 non-MAFLD controls) from a Chinese hospital were enrolled. Hepatic ultrasound measurements and thyroid function were assessed.

RESULTS

Overweight/obesity mediated the associations of MAFLD with triiodothyronine (T3), free triiodothyronine (FT3), free thyroxine (FT4), and the mediator accounted for 46.43%, 39.69%, and 42.68%, respectively. Metabolic disorder mediated the association of MAFLD with T3, FT3, FT4, thyroid stimulating hormone (TSH), and the mediator accounted for 36.57%, 23.19%, 34,65%, and 60.92%, respectively. Diabetes did not complementary mediate any association between TH and MAFLD. Elevated T3, FT3, TSH and decreased FT4 increased the risk of overweight/obesity-MAFLD, and the odds ratios were 1.59, 1.72, 1.18, and 0.60, respectively (Q4 vs.Q1, false discovery rate (FDR)<0.05). Elevated T3, FT3, and decreased FT4 increased the risk of metabolic disorder-MAFLD, and the odds ratios were 1.45, 1.33, and 0.52, respectively (Q4 vs.Q1, FDR<0.05). No significant association between TH and diabetes-MAFLD was detected.

CONCLUSION

The association between TH and MAFLD is mediated by overweight/obesity and metabolic disorders and varies among MAFLD subtypes.

Nomenclature Dilemma of Metabolic Associated Fatty Liver Disease (MAFLD): Considerable Proportions of MAFLD Are Metabolic Healthy

BACKGROUND & AIMS

The purpose of this study was to investigate the proportion of subjects with metabolic dysfunction-associated fatty liver disease (MAFLD) and to assess the degree of hepatic fibrosis and cardiovascular risk in metabolically healthy MAFLD subjects.

METHODS

A total of 6740 subjects who underwent both magnetic resonance elastography and abdominal ultrasound were included in this study. Significant (≥3.0 kPa) and advanced (≥3.6 kPa) hepatic fibrosis were evaluated by magnetic resonance elastography. The metabolic unhealthy status among subjects with MAFLD was defined as the presence of diabetes or 2 or more metabolic risk abnormalities.

RESULTS

The prevalence of MAFLD among the health examination cohort was 44.5% (3002 of 6740). A total of 26.6% (800 of 3002) of MAFLD subjects were metabolically healthy (≤1 risk factors and no diabetes), and 56.3% of MAFLD subjects (1691 of 3002) did not have metabolic syndrome. Hepatic fibrosis burden and cardiovascular risk were significantly higher in the metabolic unhealthy MAFLD group than in the healthy control group. However, the prevalence of significant (5.8% vs 4.3%; P = .099) and advanced hepatic fibrosis (0.8% vs 0.7%; P = .934) did not differ between the metabolically healthy MAFLD and healthy control groups. The prevalence of carotid artery plaque in the metabolically healthy MAFLD (32.7% vs 30.7%; P = .453) group was not different from that in the healthy control group.

CONCLUSIONS

Contrary to the definition of MAFLD, a non-negligible number of metabolically healthy individuals are included in the MAFLD group. The metabolic healthy MAFLD group showed a comparable fibrosis burden and prevalence of carotid artery plaque compared with the healthy control group.

Trends in prevalence and all-cause mortality of metabolic dysfunction-associated fatty liver disease among adults in the past three decades: Results from the NHANES study

BACKGROUND

Given the escalating epidemic of obesity and diabetes coupled with redefined diagnostic criteria, it is critical to identify the prevalence of metabolic dysfunction-associated fatty liver disease (MAFLD). We sought to determine the prevalence and mortality outcomes of MAFLD subtypes based on diagnostic criteria in the USA over the past three decades.

METHODS

Eleven cycles of the National Health and Nutrition Examination Surveys (NHANES; 1988-1994 and 1999-2020) were used, and 72,224 participants were included. MAFLD was defined according to the 2020 International Expert Consensus. Based on diagnostic criteria and risk factors, MAFLD was categorized into seven subtypes: type 1 (obesity subtype), 2 (metabolic unhealthy subtype), 3 (diabetes subtype), 4 (metabolic unhealthy non-diabetes subtype), 5 (obesity and diabetes subtype), 6 (metabolic unhealthy non-obesity subtype), and 7 (mixed subtype).

RESULTS

Over the study period, the estimated prevalence of MAFLD increased significantly from 22% in 1988-1994 to 36% in 2017-2020. The prevalence of Type 4 was the highest, followed by that of Type 7, whereas other types were low and almost unchanged over time. Individuals with MAFLD had 19% and 38% increased mortality risks from all causes and cardiovascular disease, respectively. Among them, the metabolically unhealthy participants with normal weight demonstrated a 116% higher risk for all-cause mortality [hazard ratio (HR): 2.16, 95% CI: 1.52-3.08] and a 222% higher risk for cardiovascular mortality (HR: 3.22, 95% CI: 1.72-6.04). Interestingly, stratification and interaction analyses demonstrated a significant impact of metabolic parameters on the relationship between MAFLD and all-cause mortality.

CONCLUSIONS

In conclusion, our study identified an increase in MAFLD prevalence and a significant association between metabolic derangements in MAFLD and all-cause or cardiovascular mortality.

Characteristics and long-term mortality of patients with non-MAFLD hepatic steatosis

BACKGROUND & AIMS

A cluster of hepatic steatosis without metabolic abnormalities has been excluded by the MAFLD definition, referred to as non-MAFLD steatosis. We aimed to characterize the non-MAFLD steatosis.

METHODS

We included 16,308 individuals from the UK Biobank who had magnetic resonance imaging-derived proton density fat fraction (MRI-PDFF) to describe the clinical and genetic features of non-MAFLD steatosis in a cross-sectional design, and 14,797 individuals of the NHANES III who underwent abdominal ultrasonography at baseline to assess the long-term mortality of non-MAFLD steatosis in a prospective cohort design.

RESULTS

Of 16,308 individuals in the UK Biobank, 2747 fatty liver disease (FLD) cases (2604 MAFLD and 143 non-MAFLD) and 3007 healthy controls (without metabolic dysfunctions) were identified. The mean PDFF (10.65 vs. 9.00) and the proportion of advanced fibrosis (fibrosis-4 index > 2.67, 1.27% vs. 1.40%) were comparable between MAFLD and non-MAFLD steatosis. Non-MAFLD steatosis has the highest minor allele frequency of PNPLA3 rs738409, TM6SF2 rs58542926, and GCKR rs1260326 in contrast to the other two groups. The genetic risk score calculated by PNPLA3, TM6SF2, and GCKR has a certain predictive ability for non-MAFLD steatosis (AUROC = 0.69). NHANES III population showed that compared to healthy individuals, the adjusted hazard ratio of non-MAFLD steatosis increased by 1.52 (95% confidence interval: 1.21-1.91) and 1.78 (95% confidence interval: 1.03-3.07) for all-cause and heart disease-related mortality, respectively.

CONCLUSIONS

Non-MAFLD steatosis has comparable degrees of hepatic steatosis and fibrosis to MAFLD and increases the risk of mortality. Genetic predisposition highly contributes to the risk of non-MAFLD steatosis.

Risk of subclinical atherosclerosis across metabolic transition in individuals with or without fatty liver disease: a prospective cohort study

BACKGROUND

Metabolic dysfunction is a major determinant in the progression of fatty liver disease. It is pivotal to evaluate the metabolic status and subsequent transition in fatty liver population and to identify the risk of subclinical atherosclerosis.

METHODS

The prospective cohort study included 6260 Chinese community residents during 2010-2015. Fatty liver was determined as hepatic steatosis (HS) by ultrasonography. Metabolic unhealthy (MU) status was defined as having diabetes and/or ≥ 2 metabolic risk factors. Participants were categorized into 4 groups according to the combination of metabolic healthy (MH)/MU and fatty liver status (MHNHS, MUNHS, MHHS and MUHS). Subclinical atherosclerosis was assessed by elevated brachial-ankle pulse wave velocity, pulse pressure and/or albuminuria.

RESULTS

31.3% of the participants had fatty liver disease and 76.9% were in MU status. During a 4.3-year follow-up, 24.2% of participants developed composite subclinical atherosclerosis. Multivariable adjusted odds ratios for composite subclinical atherosclerosis risk were (1.66 [1.30-2.13]) in MUNHS group and (2.57 [1.90-3.48]) in MUHS group. It seemed that participants with fatty liver disease were more prone to be remained in MU status (90.7% vs.50.8%) and less likely to regress to MH status (4.0% vs. 8.9%). Fatty liver participants progressed to (3.11 [1.23-7.92]) or maintained MU status (4.87 [3.25-7.31]) significantly impelled the development of the composite risk, while regressing to MH status (0.15 [0.04-0.64]) were more intended to mitigate the risk.

CONCLUSIONS

The current study emphasized the importance of assessing metabolic status and its dynamic changes, especially in the fatty liver population. Regressing from MU to MH status not only benefited the systematic metabolic profile but also ameliorated future cardiometabolic complications.

The Inter-Organ Crosstalk Reveals an Inevitable Link between MAFLD and Extrahepatic Diseases

Fatty liver is known to be associated with extra-hepatic diseases including atherosclerotic cardiovascular disease and extra-hepatic cancers, which affect the prognosis and quality of life of the patients. The inter-organ crosstalk is mediated by metabolic abnormalities such as insulin resistance and visceral adiposity. Recently, metabolic dysfunction-associated fatty liver disease (MAFLD) was proposed as a new definition for fatty liver. MAFLD is characterized by the inclusion criteria of metabolic abnormality. Therefore, MAFLD is expected to identify patients at high risk of extra-hepatic complications. In this review, we focus on the relationships between MAFLD and multi-organ diseases. We also describe the pathogenic mechanisms of the inter-organ crosstalk.

Association between serum uric acid levels and long-term mortality of metabolic dysfunction-associated fatty liver disease: a nationwide cohort study

BACKGROUND

The association between hyperuricemia and metabolic dysfunction-associated fatty liver disease (MAFLD) remains undetermined. This study aimed to examine the association of serum uric acid (SUA) levels with prevalence and long-term mortality of MAFLD in a nationally representative sample of US adults.

METHODS

This analysis included 11,177 participants from the Third National Health and Nutrition Examination Survey (NHANES III, 1988-1994) with matched mortality data until 2019. We used logistic regression models to estimate the adjusted odd ratios (ORs) for factors associated with risk of MAFLD, and applied restricted cubic spline (RCS) regression to assess the non-linear associations of SUA levels with all-cause and cause-specific mortality of MAFLD. We also used Cox proportional hazards regression analysis to estimate hazard ratios (HRs) for the mortality.

RESULTS

A higher SUA level contributed to a significant increased risk of MAFLD. every 1 mg/dL increment of SUA level was related to 17% (95% CI 9-24%) increased risk of MAFLD. Furthermore, a U-shaped association for males and a J-shaped association for females was discovered between SUA levels and all-cause mortality in participants with MAFLD. Specifically, among males, when SUA > 6.7 mg/dL, the higher SUA showed increased risk of cardio-cerebrovascular disease (CVD) mortality [HR (95% CI): 1.29 (1.05-1.58)]. As for females, only when SUA > 5.5 mg/dL, it showed a significantly positive association with risk of CVD and cancer mortality [HR (95% CI) 1.62 (1.24-2.13) and 1.95 (1.41-2.68)].

CONCLUSIONS

Elevated SUA level is significantly associated with an increased risk of MAFLD. Besides, SUA level is also a predictor of long-term mortality of MAFLD.

Association of MAFLD with end-stage kidney disease: a prospective study of 337,783 UK Biobank participants

INTRODUCTION

Metabolic dysfunction-associated fatty liver (MAFLD) has been found to be associated with the prevalence of chronic kidney disease (CKD). However, it is unknown whether MAFLD is associated with CKD development and the incidence of end-stage kidney disease (ESKD). We aimed to clarify the association between MAFLD and incident ESKD in the prospective UK Biobank cohort.

METHODS

We analyzed the data of 337,783 UK Biobank participants and relative risks for the ESKD were calculated by using the Cox regression analysis.

RESULTS

Among 337,783 participants over a median duration of 12.8 years follow-up, a total of 618 ESKD cases were diagnosed. Participants with MAFLD were twice likely to develop ESKD (hazard ratio [HR] 2.03, 95% confidence interval [CI] 1.68-2.46, p < 0.001). The association of MAFLD with ESKD risk remained significant in both non-CKD and CKD participants. Our results also showed that there were graded associations between liver fibrosis scores and the risk of ESKD in MAFLD cases. Compared to non-MAFLD individuals, the adjusted HRs for incident ESKD in MAFLD patients with increasing levels of NAFLD fibrosis score were 1.23 (95% CI 0.96-1.58), 2.45 (1.98-3.03) and 7.67 (5.48-10.73), respectively. Furthermore, the risking alleles of PNPLA3 rs738409, TM6SF2 rs58542926, GCKR rs1260326 and MBOAT7 rs641738 amplified the MAFLD effect on ESKD risk. In conclusion, MAFLD is associated with incident ESKD.

CONCLUSION

MAFLD may help identify the subjects at high risk of ESKD development and MAFLD interventions should be encouraged to slow down CKD progression.

Type 2 diabetes mellitus in metabolic-associated fatty liver disease vs. type 2 diabetes mellitus non-alcoholic fatty liver disease: a longitudinal cohort analysis

INTRODUCTION AND OBJECTIVES

Type 2 Diabetes Mellitus (T2DM) is comorbidity commonly presenting with fatty liver. A recently proposed definition of "metabolic associated fatty liver disease" (MAFLD) is thought to replace non-alcoholic fatty liver disease (NAFLD). Yet, despite the significant prevalence of T2DM among fatty liver, there remains limited evidence on the impact of the change in the definition of T2DM.

MATERIALS AND METHODS

The current study uses data from the United States National Health and Nutrition Examination Survey (NHANES) from 1999 to 2018. Survival analysis was conducted with a cox regression and sub-distribution hazard ratio for competing risk events.

RESULTS

6727 patients had a diagnosis of T2DM. 4982 individuals with T2DM had MAFLD and 2032 were MAFLD(+)/NAFLD(-), while 2950 patients were MAFLD(+)/NAFLD(+). The new definition increased fatty liver diagnosis by 68.89%. Patients who were classified as MAFLD(+)/NAFLD(-) were at a higher risk of major adverse cardiovascular events, advanced fibrosis, all-cause and cardiovascular-related mortality compared to MAFLD(+)/NAFLD(+). In MAFLD(+)/NAFLD(-), viral hepatitis significantly increases the odds of advanced fibrosis (OR: 6.77, CI: 3.92 to 11.7, p < 0.001) and all-cause mortality (HR: 1.75, CI: 1.29 to 2.40, p < 0.001).

CONCLUSIONS

The identification and treatment of NAFLD in patients with T2DM is a major concern and the premature change to MAFLD results in an over-diagnosis of fatty liver, exaggerated mortality, and morbidity in patients with T2DM. The definition of MAFLD causes further heterogeneity in fatty liver disease/NAFLD.

Low thyroid function is associated with an increased risk of advanced fibrosis in patients with metabolic dysfunction-associated fatty liver disease

AIMS

Observational studies showed that low thyroid function may perturb liver function. We aimed to evaluate the association of low thyroid function with both metabolic dysfunction-associated fatty liver disease (MAFLD) and advanced hepatic fibrosis.

METHODS

Participants who underwent abdominal ultrasonography and thyroid function test in a Chinese hospital from 2015 to 2021were enrolled. Fibrosis-4 index (FIB-4) > 2.67 and/or non-alcoholic fatty liver disease fibrosis score (NFS) > 0.676 were used to define advanced fibrosis. Descriptive analyses were performed to characterize the epidemiology of MAFLD according to levels of thyroid-stimulating hormone (TSH). The logistic regression model was applied to estimate the association of low thyroid function with MAFLD and advanced fibrosis.

RESULTS

A total of 19,946 participants (52.78% males, mean age: 47.31 years, 27.55% MAFLD) were included, among which 14,789 were strict-normal thyroid function, 4,328 were low-normal thyroid function, 829 were subclinical hypothyroidism. TSH levels were significantly higher in MAFLD patients with a FIB-4 > 2.67 and /or NFS > 0.676 than their counterparts. The logistic regression model adjusted for age and sex showed that low-normal thyroid function increased the risk of MAFLD (odds ratio [OR] = 1.09; 95% confidence interval [CI] 1.01-1.18). Multivariable regression model adjusted for age, sex, body mass index, type 2 diabetes, and hypertension showed low-normal thyroid function increased the risk of advanced fibrosis in patients with MAFLD (FIB-4 > 2.67: OR = 1.41, 95% CI 1.02-1.93; NFS > 0.676: OR = 1.72, 95% CI 1.08-2.72).

CONCLUSION

Elevated TSH concentrations are associated with advanced hepatic fibrosis, even in the euthyroid state.

Utility of Human Relevant Preclinical Animal Models in Navigating NAFLD to MAFLD Paradigm

Fatty liver disease is an emerging contributor to disease burden worldwide. The past decades of work established the heterogeneous nature of non-alcoholic fatty liver disease (NAFLD) etiology and systemic contributions to the pathogenesis of the disease. This called for the proposal of a redefinition in 2020 to that of metabolic dysfunction-associated fatty liver disease (MAFLD) to better reflect the current understanding of the disease. To date, several clinical cohort studies comparing NAFLD and MAFLD hint at the relevancy of the new nomenclature in enriching for patients with more severe hepatic injury and extrahepatic comorbidities. However, the underlying systemic pathogenesis is still not fully understood. Preclinical animal models have been imperative in elucidating key biological mechanisms in various contexts, including intrahepatic disease progression, interorgan crosstalk and systemic dysregulation. Furthermore, they are integral in developing novel therapeutics against MAFLD. However, substantial contextual variabilities exist across different models due to the lack of standardization in several aspects. As such, it is crucial to understand the strengths and weaknesses of existing models to better align them to the human condition. In this review, we consolidate the implications arising from the change in nomenclature and summarize MAFLD pathogenesis. Subsequently, we provide an updated evaluation of existing MAFLD preclinical models in alignment with the new definitions and perspectives to improve their translational relevance.

Association of metabolic dysfunction-associated fatty liver disease, type 2 diabetes mellitus, and metabolic goal achievement with risk of chronic kidney disease

Background

Although type 2 diabetes mellitus (T2DM) plays a significant role in the association between metabolic dysfunction-associated fatty liver disease (MAFLD) and chronic kidney disease (CKD), how T2DM development and glycemic deterioration affect CKD and its renal function indicators, estimated glomerular filtration rate (eGFR) and urine albumin-to-creatinine ratio (UACR), remains unknown. We aimed to assess the association between MAFLD, along with T2DM, and risk of CKD, and then evaluate the effect of metabolic goal achievement in MAFLD on the risk of CKD.

Methods

In this cross-sectional study, 5,594 participants were included. Multivariate logistic regression and linear regression were used to examine the association between MAFLD with its T2DM status and metabolic goal achievement and risk of CKD, as well as eGFR and UACR.

Results

The MAFLD group had a higher prevalence of CKD (16.2 vs. 7.6%, P < 0.001) than the non-MAFLD group. MAFLD was independently associated with an increased risk of CKD (odds ratio [OR]: 1.35, 95% CI: 1.09-1.67) and increased eGFR and UACR. Among the three MAFLD subtypes, only the T2DM subtype exhibited significant associations with increased risk of CKD (OR: 2.85, 95% CI: 2.24-3.63), as well as increased eGFR and UACR. Glycemic deterioration in MAFLD was dose-dependently associated with an increased risk of CKD (P-trend < 0.001). Achieved metabolic goals in MAFLD decreased the risk of CKD, eGFR, and UACR; MAFLD with 2 or 3 achieved metabolic goals was not significantly associated with the risk of CKD (OR: 0.81, 95% CI: 0.59-1.12) and albuminuria.

Conclusion

MAFLD was independently associated with an increased risk of CKD, as well as increased eGFR and UACR. This association is strongly driven by T2DM status. Glycemic deterioration in MAFLD was dose-dependently associated with an increased risk of CKD. Achieved metabolic goals in MAFLD decreased the risk of CKD by reducing the risk of albuminuria.

Long-term cardiovascular outcomes differ across metabolic dysfunction-associated fatty liver disease subtypes among middle-aged population

BACKGROUND AND AIMS

The new metabolic dysfunction-associated fatty liver disease (MAFLD) criteria include the following three distinct subtypes: MAFLD with diabetes mellitus (DM), overweight/obese (OW), or lean/normal weight with metabolic dysfunction. We investigated whether long-term cardiovascular disease outcomes differ across the MAFLD subtypes.

METHODS

From a nationwide health screening database, we included 8,412,730 participants (48.6% males) aged 40-64 years, free of cardiovascular disease history, between 2009 and 2010. Participants were categorized into non-MAFLD, OW-MAFLD, lean-MAFLD, and DM-MAFLD. The primary outcome was a composite cardiovascular disease event, including myocardial infarction, ischemic stroke, heart failure, or cardiovascular disease-related death. The presence of advanced liver fibrosis was estimated using a BARD score ≥ 2.

RESULTS

Among the study participants, 3,087,640 (36.7%) had MAFLD, among which 2,424,086 (78.5%), 170,761 (5.5%), and 492,793 (16.0%) had OW-MAFLD, lean-MAFLD, and DM-MAFLD, respectively. Over a median follow-up period of 10.0 years, 169,433 new cardiovascular disease events occurred. With the non-MAFLD group as reference, multivariable-adjusted hazard ratios (95% confidence intervals) for cardiovascular disease events were 1.16 (1.15-1.18), 1.23 (1.20-1.27), and 1.82 (1.80-1.85) in the OW-MAFLD, lean-MAFLD, and DM-MAFLD groups, respectively. Participants with lean-MAFLD or DM-MAFLD had a higher cardiovascular disease risk than those with OW-MAFLD, irrespective of metabolic abnormalities or comorbidities. The presence of advanced liver fibrosis was significantly associated with a higher cardiovascular disease risk in each MAFLD subtype.

CONCLUSION

Long-term cardiovascular disease outcomes differed across the MAFLD subtypes. Further studies are required to investigate whether preventive or therapeutic interventions should be optimized according to the MAFLD subtypes.

Lean/normal-weight metabolic dysfunction-associated fatty liver disease is a risk factor for reflux esophagitis

AIM

Reflux esophagitis is associated with metabolic dysfunction. Recently, fatty liver has been redefined as metabolic dysfunction-associated fatty liver disease (MAFLD). We investigated the impact of MAFLD and its subtypes on the incidence of reflux esophagitis.

METHODS

This multicenter, observational cohort study enrolled 9100 consecutive health-check examinees who underwent esophagogastroduodenoscopy and ultrasonography. All patients were classified into the MAFLD or non-MAFLD group. Based on the Asian cut-off value for body mass index (BMI), the MAFLD group was further classified into the lean/normal-weight (BMI <23 kg/m² ) and overweight/obese (BMI ≥23 kg/m² ) subgroups. The impact of MAFLD and its subtypes on the cumulative incidence of reflux esophagitis was evaluated using multivariable Cox proportional hazards regression analysis.

RESULTS

MAFLD was diagnosed in 26.5% (2416/9100) of patients. Multivariable Cox proportional hazards regression analysis indicated that MAFLD (hazard ratio [HR] 1.2183; 95% confidence interval [CI] 1.0954-1.3550; p = 0.0003), hiatal hernia, and aging were independent risk factors for reflux esophagitis. Stratification analysis indicated that cumulative incidence of reflux esophagitis among patients with MAFLD was significantly higher in the lean/normal-weight than in the overweight/obese group (HR 1.3274; 95% CI 1.0043-1.7547; p = 0.0466). Among various metabolic factors, visceral adiposity was the only independent metabolic risk factor for reflux esophagitis (HR 2.8331; 95% CI 1.0201-7.8691; p = 0.0457) in the lean/normal-weight MAFLD group.

CONCLUSIONS

MAFLD, in particular lean/normal-weight MAFLD, is independent risk factor for reflux esophagitis. Furthermore, visceral adiposity was identified as the most strong metabolic risk factor for reflux esophagitis in lean/normal-weight patients with MAFLD.

A new risk stratification strategy for fatty liver disease by incorporating MAFLD and fibrosis score in a large US population

BACKGROUND

Metabolic dysfunction-associated fatty liver disease (MAFLD) is a newly proposed definition of fatty liver disease (FLD) independent of excessive alcohol consumption (EAC) and hepatitis viral infection. Evidence on the mortality risk in different types of FLD [nonalcoholic FLD (NAFLD), alcoholic FLD (AFLD), and MAFLD] is sparse, hindering the identification of high-risk populations for preferential clinical surveillance.

METHODS

A total of 11,000 participants in the Third National Health and Nutrition Examination Survey were enrolled. Participants were categorized into three groups [FLD( - ), MAFLD( - ), and MAFLD( +)] according to FLD and MAFLD criteria, and further categorized into six groups by EAC. Multivariate Cox proportional hazard model was used to estimate the risk of all-cause, cardiovascular-related, and cancer-related mortality.

RESULTS

During a median follow-up of 23.2 years, a total of 3240 deaths were identified. Compared with FLD( - )/EAC( - ) participants, MAFLD( +) individuals had higher all-cause mortality risk [hazard ratio (HR) = 1.28, 95% confidence interval (CI) = 1.18-1.39] regardless of EAC status [MAFLD( +)/NAFLD: HR = 1.22, 95%CI = 1.11-1.34; MAFLD( +)/AFLD: HR = 1.83, 95%CI = 1.46-2.28], while not for MAFLD( - ) individuals. Furthermore, diabetes-driven-MAFLD had higher mortality risk (HR = 2.00, 95%CI = 1.77-2.27) followed by metabolic dysregulation-driven-MAFLD (HR = 1.30, 95%CI = 1.06-1.60) and overweight/obesity-driven-MAFLD (HR = 1.11, 95%CI = 1.00-1.22). Additionally, MAFLD( - ) participants with elevated fibrosis score were also associated with statistically significantly higher mortality risk (HR = 3.23, 95%CI = 1.63-6.40).

CONCLUSIONS

Utilizing a representative sample of the US population, we proved the validity of MAFLD subtype and fibrosis score, rather than the traditional definition (NAFLD and AFLD), in the risk stratification of FLD patients. These findings may be applied to guide the determination of surveillance options for FLD patients.

MAFLD: what 2 years of the redefinition of fatty liver disease has taught us

Metabolic dysfunction-associated fatty liver disease (MAFLD) has appeared as the leading liver disease worldwide. Whereas the terminology nonalcoholic fatty liver disease (NAFLD) mainly reflected a negative selection and exclusion of alcohol-related liver disease (ALD), the new definition made its focus on the association of MAFLD with overweight/obesity, type 2 diabetes and metabolic risk factors especially also in normal weight/lean subjects. Several studies from the past 2 years have now used the new definition and have provided substantial information that this new definition might be accurate. Studies from the past 2 years have provided evidence that the new definition might be especially advantageous in the characterization and identification of patients with significant fibrosis. This has also been demonstrated in the well-known Rotterdam study in which the MAFLD-only group showed a higher rate of fibrosis and liver stiffness. MAFLD might also be able to predict all-cause mortality as demonstrated in the Third National Health and Nutrition Examination Survey. Furthermore, MAFLD might improve characterization of the cardiovascular risk of this patient population. As the term MAFLD has not yet been accepted universally, it remains important to coordinate efforts globally to adapt to this new definition and especially involve all specialities dealing with metabolic disorders such as diabetologists to further improve its definition and to prepare the medical community for its future use. The aim of this review is to summarize and critically address evidence emerging over the past 2 years that usage of the term MAFLD could be helpful in daily clinical practice.

Association of Metabolic Dysfunction-Associated Fatty Liver Disease With Left Ventricular Diastolic Function and Cardiac Morphology

BACKGROUND AND AIM

Non-alcoholic fatty liver disease (NAFLD) is closely related to cardiovascular diseases (CVD). A newly proposed definition is metabolic dysfunction-associated fatty liver disease (MAFLD), which was changed from NAFLD. The clinical effect of this change on abnormalities of cardiac structure and function is yet unknown. We aimed to examine whether MAFLD is associated with left ventricular (LV) diastolic dysfunction (LVDD) and cardiac remolding and further identify the impact of different subgroups and severity of MAFLD.

METHOD

We evaluated 228 participants without known CVDs. Participants were categorized by the presence of MAFLD and the normal group. Then, patients with MAFLD were subclassified into three subgroups: MAFLD patients with diabetes (diabetes subgroup), overweight/obesity patients (overweight/obesity subgroup), and lean/normal-weight patients who had two metabolic risk abnormalities (lean metabolic dysfunction subgroup). Furthermore, the severity of hepatic steatosis was assessed by transient elastography (FibroScan^®) with a controlled attenuation parameter (CAP), and patients with MAFLD were divided into normal, mild, moderate, and severe hepatic steatosis groups based on CAP value. Cardiac structure and function were examined by echocardiography.

RESULTS

LVDD was significantly more prevalent in the MAFLD group (24.6% vs. 60.8%, p < 0.001) compared to the normal group. The overweight subgroup and diabetes subgroup were significantly associated with signs of cardiac remolding, including interventricular septum thickness, LV posterior wall thickness, left atrial diameter (all p < 0.05), relative wall thickness, and LV mass index (all p < 0.05). Additionally, moderate-to-to severe steatosis patients had higher risks for LVDD and cardiac remolding (all p-values < 0.05).

CONCLUSION

MAFLD was associated with LVDD and cardiac remolding, especially in patients with diabetes, overweight patients, and moderate-to-to severe steatosis patients. This study provides theoretical support for the precise prevention of cardiovascular dysfunction in patients with MAFLD.