Association Between Metabolic Associated Fatty Liver Disease and Chronic Kidney Disease: A Cross-Sectional Study from NHANES 2017-2018

Associations of dietary inflammatory index with low estimated glomerular filtration rate, albuminuria and chronic kidney disease in U.S adults: Results from the NHANES 2011-2018

BACKGROUND AND AIMS

Chronic Kidney Disease (CKD) is characterized by a high inflammation status with ever-increasing prevalence, and defined as low estimated glomerular filtration rate (eGFR) or albuminuria. Both low eGFR and albuminuria can have independent effects on the body. The dietary inflammatory index (DII) is a validated tool used to assess the inflammatory potential of the diet. We aim to explore not only the association between DII and CKD, but also the associations of DII with low eGFR and albuminuria, respectively. In addition, their associations in different subgroups remain to be explored.

METHODS AND RESULTS

18,070 participants from the 2011-2018 NHANES with complete data of dietary intake and laboratory data were involved in our study. The data of 24-hour dietary recall interview was used to calculate DII, CKD could be reflected by laboratory data of creatinine and albumin. Then weighted multivariate logistic regression models and subgroup analyses were performed. The prevalence of low eGFR, albuminuria and CKD were 6.8%, 9.8% and 14.5%, respectively. A positive association between DII and low eGFR was observed (OR=1.12, 95%CI: 1.05-1.21), Q2, Q3 and Q4 are positively associated with a significant 39%, 65% and 71% increased risk of low eGFR compared with Q1 (P for trend<0.05). DII was also associated with CKD (OR=1.06, 95%CI: 1.01-1.11).

CONCLUSION

Significant positive associations of DII with CKD and low eGFR were observed. But we didn't find such association between DII and albuminuria.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Prevalence and risk factors of MAFLD and its metabolic comorbidities in community-based adults in China: A cross-sectional study

AIMS

There is a growing interest in the co-management of metabolic dysfunction-associated fatty liver disease (MAFLD) and its metabolic comorbidities. However, there is insufficient epidemiological data regarding MAFLD and its metabolic comorbidities in China. This study aims to investigate the prevalence and risk factors of MAFLD and its metabolic comorbidities.

METHODS

9171 participants were recruited in this cross-sectional study, utilizing a multistage, stratified sampling method. All participants underwent a comprehensive assessment. The diagnosis of MAFLD was based on vibration-controlled transient elastography (VCTE). The prevalence of MAFLD and its metabolic comorbidities was calculated. Binary and ordinary logistic regressions were conducted.

RESULTS

The overall weighted prevalence of MAFLD was 21.18%. Of the 2081 adults with MAFLD, 1866 (89.67%) had more than one metabolic comorbidity, and only 215 (10.33%) did not have comorbidity. Among the population with MAFLD, the prevalence of dyslipidemia, hypertension, hyperuricemia, and diabetes was 67.47%, 43.73%, 39.10%, and 33.88%, respectively. Advanced age, male gender, overweight/obesity, excessive alcohol consumption, and elevated HOMA-IR levels were positively correlated with the number of MAFLD-related metabolic comorbidities.

CONCLUSIONS

A significant proportion of individuals diagnosed with MAFLD presented with metabolic comorbidities. Therefore, engaging in the co-management of MAFLD and its metabolic comorbidities is imperative.

Circulating hormones in biopsy-proven steatotic liver disease and steatohepatitis: A Multicenter Observational Study

BACKGROUND

The role of metabolic/inflammatory hormonal systems in metabolic dysfunction associated steatotic liver disease (MASLD) remains to be fully elucidated.

PURPOSE

To report the levels of the novel total and H-specific growth differentiation factor-15 (GDF-15) and other established hormonal systems and to describe hormonal patterns in controls and patients with MASLD and its stages.

METHODS

This is a multicenter study from two Gastroenterology-Hepatology Departments (Greece and Australia) and one Bariatric-Metabolic Surgery Department (Italy). Overall, n = 455 serum samples of patients with biopsy-proven MASLD (n = 374) and Controls (n = 81) were recruited.

RESULTS

We report for the first time that total and H-specific GDF-15 levels are higher in MASLD, at-risk metabolic dysfunction associated steatohepatitis (MASH), and severe fibrosis than in Controls. In addition, follistatin-like-3 (FSTL-3), free insulin-like growth factor-1 (IGF-1), leptin, and insulin levels were higher in MASLD patients than in Controls, while adiponectin levels were lower in MASLD subjects than in Controls. Activin-A, follistatin (FST), FSTL-3, and insulin levels significantly increased in severe fibrosis compared to no/mild fibrosis, while free IGF-1 decreased. In addition, adiponectin levels were lower in subjects without fibrosis vs. any fibrosis. Moreover, GDF-15 presented a strong positive association for the likelihood of having MASLD and at-risk MASH, while in adjusted analyses, FST and adiponectin showed inverse associations. Two different patterns of at-risk MASH were revealed through unsupervised analysis (total variation explained=54%). The most frequent pattern met in our sample (34.3%) was characterized by higher levels of total and H-specific GDF-15, follistatins, and activins, as well as low adiponectin levels. The second pattern revealed was characterized by high levels of free IGF-1, insulin, and leptin, with low levels of activin-A and adiponectin. Similar patterns were also generated in the case of overall MASLD.

CONCLUSIONS

Total and H-specific GDF-15 levels increase as MASLD severity progresses. FSTL-3, free IGF-1, leptin, and insulin are also higher, whereas adiponectin and activin-A levels are lower in the MASLD group than in Controls. Hormonal systems, including GDF-15, may not only be involved in the pathophysiology but could also prove useful for the diagnostic workup of MASLD and its stages and may potentially be of therapeutic value.

Towards an adiposity-related disease framework for the diagnosis and management of obesities

Obesity is a complex disease that relapses frequently and associates with multiple complications that comprise a worldwide health priority because of its rising prevalence and association with numerous complications, including metabolic disorders, mechanic pathologies, and cancer, among others. Noteworthy, excess adiposity is accompanied by chronic inflammation, oxidative stress, insulin resistance, and subsequent organ dysfunction. This dysfunctional adipose tissue is initially stored in the visceral depot, overflowing subsequently to produce lipotoxicity in ectopic depots like liver, heart, muscle, and pancreas, among others. People living with obesity need a diagnostic approach that considers an exhaustive pathophysiology and complications assessment. Thus, it is essential to warrant a holistic diagnosis and management that guarantees an adequate health status, and quality of life. The present review summarizes the different complications associated with obesity, at the same time, we aim to fostering a novel framework that enhances a patient-centered approach to obesity management in the precision medicine era.

Utility of non-invasive liver fibrosis markers to predict the incidence of chronic kidney disease (CKD): A systematic review, meta-analysis, and meta-regression

BACKGROUND AND AIMS

Chronic kidney disease (CKD) and non-alcoholic fatty liver disease (NAFLD) share common risk factors and pathogenesis mechanisms. However, the association between the degree of liver fibrosis and the incidence of CKD remains unclear. This study aims to examine the utility of non-invasive fibrosis markers to predict the occurrence of CKD.

METHODS

Cochrane Library, Scopus, and Medline were searched up to May 20th, 2023 using combined keywords. Literature that analyzes FIB-4, NFS, and APRI to predict CKD incidence was included in this review. We used random-effect models of odds ratio (OR) with 95% confidence intervals (CI) to express the outcomes in this review.

RESULTS

Twenty-one studies were included. Our meta-analysis showed that high FIB-4 was associated with a higher incidence of CKD (OR 2.51; 95%CI: 1.87-3.37, p < 0.00001, I2 = 96%). Further regression analysis revealed that this association was significantly influenced by hypertension (p = 0.0241), NAFLD (p = 0.0029), and body mass index (BMI) (p = 0.0025). Our meta-analysis also showed that high NFS (OR 2.49; 95%CI: 1.89-3.30, p < 0.00001, I2 = 96%) and high APRI (OR 1.40; 95%CI: 1.14-1.72, p = 0.001, I2 = 26%) were associated with a higher incidence of CKD.

CONCLUSIONS

This study suggests that these non-invasive liver fibrosis markers can be routinely measured both in NAFLD patients and the general population to enable better risk stratification and early detection of CKD.

Insulin resistance and adipose tissue interactions as the cornerstone of metabolic (dysfunction)-associated fatty liver disease pathogenesis

The relationship between metabolic derangements and fatty liver development are undeniable, since more than 75% of patients with type 2 diabetes mellitus present with fatty liver. There is also significant epidemiological association between insulin resistance (IR) and metabolic (dysfunction)-associated fatty liver disease (MAFLD). For little more than 2 years, the nomenclature of fatty liver of non-alcoholic origin has been intended to change to MAFLD by multiple groups. While a myriad of reasons for which MAFLD is thought to be of metabolic origin could be exposed, the bottom line relies on the role of IR as an initiator and perpetuator of this disease. There is a reciprocal role in MAFLD development and IR as well as serum glucose concentrations, where increased circulating glucose and insulin result in increased de novo lipogenesis by sterol regulatory element-binding protein-1c induced lipogenic enzyme stimulation; therefore, increased endogenous production of triglycerides. The same effect is achieved through impaired suppression of adipose tissue (AT) lipolysis in insulin-resistant states, increasing fatty acid influx into the liver. The complementary reciprocal situation occurs when liver steatosis alters hepatokine secretion, modifying fatty acid metabolism as well as IR in a variety of tissues, including skeletal muscle, AT, and the liver. The aim of this review is to discuss the importance of IR and AT interactions in metabolic altered states as perhaps the most important factor in MAFLD pathogenesis.

Uric acid en route to gout

Gout and hyperuricemia (HU) have generated immense attention due to increased prevalence. Gout is a multifactorial metabolic and inflammatory disease that occurs when increased uric acid (UA) induce HU resulting in monosodium urate (MSU) crystal deposition in joints. However, gout pathogenesis does not always involve these events and HU does not always cause a gout flare. Treatment with UA-lowering therapeutics may not prevent or reduce the incidence of gout flare or gout-associated comorbidities. UA exhibits both pro- and anti-inflammation functions in gout pathogenesis. HU and gout share mechanistic and metabolic connections at a systematic level, as shown by studies on associated comorbidities. Recent studies on the interplay between UA, HU, MSU and gout as well as the development of HU and gout in association with metabolic syndromes, non-alcoholic fatty liver disease (NAFLD), and cardiovascular, renal and cerebrovascular diseases are discussed. This review examines current and potential therapeutic regimens and illuminates the journey from disrupted UA to gout.

An international Delphi consensus statement on metabolic dysfunction-associated fatty liver disease and risk of chronic kidney disease

BACKGROUND

With the rising global prevalence of fatty liver disease related to metabolic dysfunction, the association of this common liver condition with chronic kidney disease (CKD) has become increasingly evident. In 2020, the more inclusive term metabolic dysfunction-associated fatty liver disease (MAFLD) was proposed to replace the term non-alcoholic fatty liver disease (NAFLD). The observed association between MAFLD and CKD and our understanding that CKD can be a consequence of underlying metabolic dysfunction support the notion that individuals with MAFLD are at higher risk of having and developing CKD compared with those without MAFLD. However, to date, there is no appropriate guidance on CKD in individuals with MAFLD. Furthermore, there has been little attention paid to the link between MAFLD and CKD in the Nephrology community.

METHODS AND RESULTS

Using a Delphi-based approach, a multidisciplinary panel of 50 international experts from 26 countries reached a consensus on some of the open research questions regarding the link between MAFLD and CKD.

CONCLUSIONS

This Delphi-based consensus statement provided guidance on the epidemiology, mechanisms, management and treatment of MAFLD and CKD, as well as the relationship between the severity of MAFLD and risk of CKD, which establish a framework for the early prevention and management of these two common and interconnected diseases.

The association between metabolic dysfunction-associated fatty liver disease and chronic kidney disease: A systematic review and meta-analysis

BACKGROUND AND AIMS

The term metabolic dysfunction-associated fatty liver disease (MAFLD) has been established to better define patients with fatty liver disease who also present with metabolic dysfunction. However, the association between MAFLD and chronic-kidney disease (CKD) remains elusive.

METHODS

. We conducted systematic literature searching across multiple databases-PubMed, EMBASE, Cochrane library, and Google Scholar up until June 9th, 2022. The main exposure was the diagnosis of MAFLD and nonalcoholic fatty liver disease (NAFLD) regardless of the diagnostic modalities being used. The outcome of interest was the prevalence or the incidence of CKD.

RESULTS

There were 355,886 subjects from 11 included studies with the period of follow up of 4.6-6.5 years. Meta-analysis of cross-sectional studies showed that MAFLD was associated with a higher prevalent CKD (OR 1.50, 95%CI [1.02-2.23]; test for overall effect Z = 2.04, p = 0.04; I² = 97.7%, p < 0.001) and incident CKD (adjusted HR 1.35, 95%CI [1.18-1.52]; test for overall effect Z = 15.47, p < 0.001; I² = 84.6%, p < 0.001) and did not vary between age, sex, comorbidities, study region, and follow-up duration. No difference in CKD prevalence was found between MAFLD and NAFLD patients. Significant liver fibrosis, but not steatosis in was associated with greater odds of developing CKD. More severe MAFLD was also associated with higher odds of developing CKD.

CONCLUSION

This present meta-analysis using a large population indicates a significant association between MAFLD and the prevalence and incidence of CKD.

Comparison between metabolic-associated fatty liver disease and nonalcoholic fatty liver disease: From nomenclature to clinical outcomes

As a result of the obesity epidemic, Nonalcoholic fatty liver disease (NAFLD) and its complications have increased among millions of people. Consequently, a group of experts recommended changing the term NAFLD to an inclusive terminology more reflective of the underlying pathogenesis; metabolic-associated fatty liver disease (MAFLD). This new term of MAFLD has its own disease epidemiology and clinical outcomes prompting efforts in studying its differences from NAFLD. This article discusses the rationale behind the nomenclature change, the main differences, and its clinical implications.

The Impact of COVID-19 Pandemic Lockdown on the Relationship between Pediatric MAFLD and Renal Function

BACKGROUND

Both direct and indirect effects of COVID-19 have been found in all age groups. In particular, adult data demonstrated significant changes in patients with chronic and metabolic disease (e.g., obesity, diabetes, chronic kidney disease (CKD), and metabolic associated fatty liver dysfunction (MAFLD)), while similar pediatric evidence is still limited. We aimed at investigating the impact of the COVID-19 pandemic lockdown on the relationship between MAFLD and renal function in children with CKD due to congenital abnormalities of the kidney and urinary tract (CAKUT).

METHODS

A total of 21 children with CAKUT and CKD ≥ stage 1 underwent a comprehensive evaluation within 3 months before and 6 months after the first Italian lockdown.

RESULTS

At follow-up, CKD patients with MAFLD presented higher BMI-SDS, serum uric acid, triglycerides, and microalbuminuria levels and lower eGFR levels than those without MAFLD (all p < 0.05). Higher ferritin and white blood cell concentrations were also found in patients with CKD diagnosed with MAFLD than peers without MAFLD (both p = 0.01). Compared to children without MAFLD, a higher delta of BMI-SDS, eGFR levels, and microalbuminuria levels was found in patients with MAFLD.

CONCLUSIONS

Due to the negative influence of the COVID-19 lockdown on cardiometabolic health in childhood, a careful management of children with CKD is warranted.

Metabolic dysfunction-associated fatty liver disease predicts new onset of chronic kidney disease better than fatty liver or nonalcoholic fatty liver disease

BACKGROUND

Possible associations of chronic kidney disease (CKD) with fatty liver (FL) and nonalcoholic fatty liver disease (NAFLD) have recently been focused on. Metabolic dysfunction-associated fatty liver disease (MAFLD), defined as FL with overweight/obesity, type 2 diabetes mellitus or metabolic abnormalities, has been proposed as a new feature of chronic liver disease. However, the relationship between MAFLD and new onset of CKD has not been fully addressed.

METHODS

We investigated the associations of FL, NAFLD and MAFLD with the development of CKD, defined as an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2 or positive for urinary protein, over a 10-year period in 28 890 Japanese subjects who received annual health examinations. After exclusion of subjects with no data for abdominal ultrasonography and subjects with CKD at baseline, a total of 13 159 subjects (men 8581, women 4578; mean age 48 years) were recruited.

RESULTS

The prevalence of FL, NAFLD and MAFLD was 34.6% (men 45.1%, women 15.1%), 32.8% (men 42.7%, women 14.5%) and 32.3% (men 42.4%, women 13.4%), respectively. During the 10-year follow-up period, 2163 subjects (men 1475, women 688) had new onset of CKD. Multivariable Cox proportional hazards model analyses showed that MAFLD [hazard ratio 1.12 (95% confidence interval 1.02-1.26); P = .027] but not FL or NAFLD was an independent risk factor for new onset of CKD after adjustment of age, sex, eGFR, current smoking habit, ischemic heart disease, diabetes mellitus, overweight/obesity, hypertension and dyslipidemia. The addition of MAFLD [continuous net reclassification improvement (NRI) 0.154, integrated discrimination improvement (IDI) 0.0024] to traditional risk factors without metabolic abnormalities significantly improved the discriminatory capacity better than did the addition of FL (NRI 0.138, IDI 0.0018) or NAFLD (NRI 0.132, IDI 0.0017).

CONCLUSIONS

MAFLD is modestly and independently associated with new onset of CKD and predicts the risk for development of CKD better than FL or NAFLD.

Multifactorial Diseases of the Heart, Kidneys, Lungs, and Liver and Incident Cancer: Epidemiology and Shared Mechanisms

Within the aging population, the frequency of cancer is increasing dramatically. In addition, multiple genetic and environmental factors lead to common multifactorial diseases, including cardiovascular disease, chronic kidney disease, chronic obstructive pulmonary disease, and metabolic-associated fatty liver disease. In recent years, there has been a growing awareness of the connection between cancer and multifactorial diseases, as well as how one can affect the other, resulting in a vicious cycle. Although the exact mechanistic explanations behind this remain to be fully explored, some progress has been made in uncovering the common pathologic mechanisms. In this review, we focus on the nature of the link between cancer and common multifactorial conditions, as well as specific shared mechanisms, some of which may represent either preventive or therapeutic targets. Rather than organ-specific interactions, we herein focus on the shared mechanisms among the multifactorial diseases, which may explain the increased cancer risk. More research on this subject will highlight the significance of developing new drugs that target multiple systems rather than just one disease.

Prevalence of metabolic dysfunction-associated fatty liver disease in kidney transplant recipients: A cross-sectional study using FibroScan

BACKGROUND AND AIM

Metabolic dysfunction-associated fatty liver disease (MAFLD) is expected to be prevalent among kidney transplant recipients (KTRs). In this study, we evaluated the prevalence of MAFLD among KTRs, data that have not been investigated by any clinical study to date.

MATERIALS AND METHODS

We included a total of 52 KTRs and 53 age-, sex-, and BMI-matched individuals as the control group through prospective consecutive recruitment. We detected the presence of hepatic steatosis and liver fibrosis using the controlled attenuation parameter (CAP) and liver stiffness measurement (LSM) defined by FibroScan.

RESULTS

Among the KTRs, 18 (34.6%) had metabolic syndrome. The prevalence of MAFLD among the KTRs and controls was 42.3% and 51.9%, respectively (p=0.375). The CAP and LSM values did not differ significantly between the KTRs and controls (p=0.222 and p=0.119). Among the KTRs, patients with MAFLD had significantly higher age, BMI, waist circumference, LDL, and total cholesterol levels (p<0.001, p=0.011, p=0.033, p=0.022, and p=0.029, respectively). In multivariable analysis, age was the only independent factor for MAFLD among the KTRs (OR: 1.120, 95% confidence interval (CI): 1.039-1.208).

CONCLUSION

MAFLD among KTRs did not show a significantly higher prevalence compared to the normal population. Further clinical studies with larger populations are needed.

MAFLD: a multisystem disease

Nonalcoholic fatty liver disease (NAFLD), affecting about 25% of general population and more than 50% of dysmetabolic patients, is an emerging cause of chronic liver disease and its complications. Recently, an international consensus of experts proposed to rename this disease as 'Metabolic dysfunction-Associated Fatty Liver Disease' (MAFLD) to focus on the bidirectional interplay between fatty liver and metabolic alterations and to stress the need of assessing fatty liver independently from alcohol consumption and other coexisting causes of liver disease. The peculiarity of NAFLD/MAFLD lies in the presence of a higher risk of not only - as expected - liver-related events but also of extrahepatic events, mostly cardiovascular and cancers. Available evidence suggests that these associations are not only the expression of sharing the same risk factors but shed light about the ability of NAFLD/MAFLD and particularly of its progressive form - nonalcoholic/metabolic dysfunction-associated steatohepatitis - to act as an independent risk factor via promotion of atherogenic dyslipidemia and a proinflammatory, profibrogenic, and procoagulant systemic environment. The present review summarizes available epidemiological and clinical evidence supporting the concept of NAFLD/MAFLD as a multisystemic disease, and highlights potential explanatory mechanisms underlying the association between NAFLD/MAFLD and extrahepatic disorders.

Interplay between metabolic dysfunction-associated fatty liver disease and chronic kidney disease: Epidemiology, pathophysiologic mechanisms, and treatment considerations

The recently proposed nomenclature change from non-alcoholic fatty liver disease to metabolic dysfunction-associated fatty liver disease (MAFLD) has resulted in the reappraisal of epidemiological trends and associations with other chronic diseases. In this context, MAFLD appears to be tightly linked to incident chronic kidney disease (CKD). This association may be attributed to multiple shared risk factors including type 2 diabetes mellitus, arterial hypertension, obesity, dyslipidemia, and insulin resistance. Moreover, similarities in their molecular pathophysiologic mechanisms can be detected, since inflammation, oxidative stress, fibrosis, and gut dysbiosis are highly prevalent in these pathologic states. At the same time, lines of evidence suggest a genetic predisposition to MAFLD due to gene polymorphisms, such as the PNPLA3 rs738409 G allele polymorphism, which may also propagate renal dysfunction. Concerning their management, available treatment considerations for obesity (bariatric surgery) and novel antidiabetic agents (glucagon-like peptide 1 receptor agonists, sodium-glucose co-transporter 2 inhibitors) appear beneficial in preclinical and clinical studies of MAFLD and CKD modeling. Moreover, alternative approaches such as melatonin supplementation, farnesoid X receptor agonists, and gut microbiota modulation may represent attractive options in the future. With a look to the future, additional adequately sized studies are required, focusing on preventing renal complications in patients with MAFLD and the appropriate management of individuals with concomitant MAFLD and CKD.

MAFLD and CKD: An Updated Narrative Review

Accumulating evidence now indicates that non-alcoholic fatty liver disease (NAFLD), which is the most common chronic liver disease observed in clinical practice worldwide, is independently associated with an increased risk of incident chronic kidney disease (CKD). Given that NAFLD is linked to insulin resistance, obesity and type 2 diabetes mellitus, an international panel of experts have recently proposed a name change from NAFLD to metabolic associated fatty liver disease (MAFLD). Since the diagnostic criteria for NAFLD and MAFLD are different, observational studies assessing the potential concordance (or even superiority) of MAFLD, compared with NAFLD, in detecting patients at increased risk of hepatic and extra-hepatic complications (including CKD) are required. Hence, in the last two years, some observational studies have investigated the potential relationship between MAFLD and CKD. The result is that, at present, evidence regarding the concordance or even superiority of MAFLD, compared with NAFLD, in detecting patients at higher risk of CKD is still preliminary, although some data indicate that MAFLD identifies patients with CKD as accurately as NAFLD. In this narrative review, we will discuss: (a) the epidemiological evidence assessing the association between NAFLD and risk of incident CKD, (b) the epidemiological data investigating the association between MAFLD and risk of CKD and (c) the biological mechanisms underlying the association between NAFLD/MAFLD and CKD.

Association of metabolic dysfunction-associated fatty liver disease with kidney disease

Non-alcoholic fatty liver disease (NAFLD) is characterized by the accumulation of fat in more than 5% of hepatocytes in the absence of excessive alcohol consumption and other secondary causes of hepatic steatosis. In 2020, the more inclusive term metabolic (dysfunction)-associated fatty liver disease (MAFLD) - defined by broader diagnostic criteria - was proposed to replace the term NAFLD. The new terminology and revised definition better emphasize the pathogenic role of metabolic dysfunction and uses a set of definitive, inclusive criteria for diagnosis. Diagnosis of MAFLD is based on evidence of hepatic steatosis (as assessed by liver biopsy, imaging techniques or blood biomarkers and scores) in persons who are overweight or obese and have type 2 diabetes mellitus or metabolic dysregulation, regardless of the coexistence of other liver diseases or excessive alcohol consumption. The known association between NAFLD and chronic kidney disease (CKD) and our understanding that CKD can occur as a consequence of metabolic dysfunction suggests that individuals with MAFLD - who by definition have fatty liver and metabolic comorbidities - are at increased risk of CKD. In this Perspective article, we discuss the clinical associations between MAFLD and CKD, the pathophysiological mechanisms by which MAFLD may increase the risk of CKD and the potential drug treatments that may benefit both conditions.

Liver Steatosis: Better Predictor of CKD in MAFLD Than Liver Fibrosis as Determined by Transient Elastography With Controlled Attenuation Parameter

Background: Changing the term/concept of the non-alcoholic fatty liver disease (NAFLD) to metabolic dysfunction associated fatty liver disease (MAFLD) may broaden the pathological definition that can include chronic renal involvement, and, possibly, changes chronic kidney disease's (CKD's) epidemiological association with liver disease, because CKD is associated with metabolic disorders and almost all patients with CKD present some form of an atherogenic dyslipidemia. Our study explores the relationship between MAFLD and CKD using Transient Elastography (TE) with a Controlled Attenuated Parameter (CAP).

Methods: We evaluated 335 patients with diabetes with MAFLD and with high CKD risk using TE with CAP (FibroScan®). The CKD was defined according to Kidney Disease Improving Global Outcomes (KDIGO) 2012 guidelines. Logistic regression and stepwise multiple logistic regression were used to evaluate the factors associated with CKD. In addition, a receiver operating characteristic curve (ROC) analysis was used to assess the performance of CAP and TE in predicting CKD and its optimal threshold.

Results: The prevalence of CKD in our group was 60.8%. Patients with CKD had higher mean liver stiffness measurements (LSM) and CAP values than those without CKD. We found that hepatic steatosis was a better predictor of CKD than fibrosis. Univariate regression showed that CAP values >353 dB/m were predictive of CKD; while the multivariate regression analysis (after adjustment according to sex, body mass index (BMI), low-density lipoprotein cholesterol (LDLc), and high-density lipoprotein cholesterol (HDLc), and fasting glucose) showed that CAP values >353 dB/m were more strongly associated with the presence of CKD compared to the LSM (fibrosis) values.

Conclusion: In patients with MAFLD, CAP-assessed steatosis appears to be a better predictor of CKD compared to LSM-assessed hepatic fibrosis.

Metabolic associated fatty liver disease is a risk factor for chronic kidney disease

Background and Aims

To clarify the relationship between metabolic dysfunction‐associated fatty liver disease (MAFLD) and chronic kidney disease (CKD).

Methods

The participants were divided into four groups by the presence or absence of fatty liver disease (FLD) and metabolic dysfunction (MD). MAFLD was defined as having both FLD and MD, whereas CKD was defined as having an estimated glomerular filtration rate of <60 mL/min/1.73 m² and/or proteinuria.

Results

In this cross‐sectional study of 27,371 participants, the proportions of those in the non‐FLD without MD, non‐FLD with MD, FLD without MD, and MAFLD groups were 48.7, 28.2, 2.3, and 20.8%, respectively. Compared with non‐FLD without MD, MAFLD was associated with the risk of CKD (adjusted odds ratio 1.83 [1.66–2.01], P < 0.001), whereas FLD without MD was not (1.02 [0.79–1.33], P = 0.868). Moreover, compared with FLD without MD, MAFLD was associated with the risk of CKD (1.19 [1.09–1.31], P < 0.001). In this retrospective cohort study, 16,938 of 27,371 participants underwent a median 4.6 (2.0–8.1) years follow‐up, and incident data of non‐FLD without MD, non‐FLD with MD, FLD without MD, and MAFLD were 21.0, 31.1, 26.1, and 31.1 cases per 1,000 person‐years, respectively. Compared with the non‐FLD without MD, MAFLD was associated with the risk of incident CKD (adjusted hazard ratio 1.24 [1.14–1.36], P < 0.001), whereas FLD without MD was not (1.11 [0.85–1.41], P = 0.433).

Conclusions

MAFLD was associated with a risk of CKD, whereas FLD without MD was not a risk for CKD.