Higher Serum Uric Acid Level Predicts Non-alcoholic Fatty Liver Disease: A 4-Year Prospective Cohort Study

Machine Learning Identifies Metabolic Dysfunction-Associated Steatotic Liver Disease in Patients With Diabetes Mellitus

CONTEXT

The presence of metabolic dysfunction-associated steatotic liver disease (MASLD) in patients with diabetes mellitus (DM) is associated with a high risk of cardiovascular disease, but is often underdiagnosed.

OBJECTIVE

To develop machine learning (ML) models for risk assessment of MASLD occurrence in patients with DM.

METHODS

Feature selection determined the discriminative parameters, utilized to classify DM patients as those with and without MASLD. The performance of the multiple logistic regression model was quantified by sensitivity, specificity, and percentage of correctly classified patients, and receiver operating characteristic (ROC) curve analysis. Decision curve analysis (DCA) assessed the model's net benefit for alternative treatments.

RESULTS

We studied 2000 patients with DM (mean age 58.85 ± 17.37 years; 48% women). Eight parameters: age, body mass index, type of DM, alanine aminotransferase, aspartate aminotransferase, platelet count, hyperuricaemia, and treatment with metformin were identified as discriminative. The experiments for 1735 patients show that 744/991 (75.08%) and 586/744 (78.76%) patients with/without MASLD were correctly identified (sensitivity/specificity: 0.75/0.79). The area under ROC (AUC) was 0.84 (95% CI, 0.82-0.86), while DCA showed a higher clinical utility of the model, ranging from 30% to 84% threshold probability. Results for 265 test patients confirm the model's generalizability (sensitivity/specificity: 0.80/0.74; AUC: 0.81 [95% CI, 0.76-0.87]), whereas unsupervised clustering identified high-risk patients.

CONCLUSION

A ML approach demonstrated high performance in identifying MASLD in patients with DM. This approach may facilitate better risk stratification and cardiovascular risk prevention strategies for high-risk patients with DM at risk of MASLD.

Prevalence and association of hyperuricemia with liver function in Saudi Arabia: a large cross-sectional study

BACKGROUND

Hyperuricemia is linked to an increased risk of various chronic diseases, but data on the prevalence and association of hyperuricemia with liver function in Saudi Arabia are scarce.

OBJECTIVES

Evaluate the prevalence, association, and risk measures of hyperuricemia and liver function in the Saudi population.

DESIGN

Retrospective, cross-sectional analysis.

SETTING

Database on large portion of Saudi population.

PATIENTS AND METHODS

Laboratory data, age, and gender of the studied subjects were collected from Al Borg Diagnostics. Subjects were stratified, based on their uric acid (UA) levels, into three groups: hypouricemic, normouricemic, and hyperuricemic. The association of UA with liver enzymes was examined in all three groups.

MAIN OUTCOME MEASURES

Association of serum UA levels with alanine transaminase (ALT), aspartate transferase (AST), alkaline phosphatase (ALP), and total bilirubin (TB).

SAMPLE SIZE

13 314 subjects.

RESULTS

Our study showed that the prevalence of hyperuricemia in the Saudi population is 17.3% (20.3% in males and 15.1% in females). We also found a positive correlation between ALT, AST, and TB with UA levels. The risk of being hyperuricemic was significantly increased in individuals with elevated ALT, AST, and TB. Individuals with elevated ALT, AST, and total TB had a higher chance of having hyperuricemia than those with normal activity. Notably, ALT, AST, and TB had good discriminating capacity for hyperuricemia.

CONCLUSIONS

Hyperuricemia is highly prevalent in the Saudi population and is associated with compromised liver function. However, further studies are needed to elucidate the mechanisms underlying these findings in large prospective cohort studies in different populations.

LIMITATIONS

Lack of data on other potential confounding variables.

Bidirectional relationship between nonalcoholic fatty liver disease and serum creatinine-to-body weight ratio as a proxy for skeletal muscle mass index

BACKGROUND AND AIM

Although an association between skeletal muscle mass index and nonalcoholic fatty liver disease (NAFLD) has previously been demonstrated, the causal direction remains unclear. Herein, we investigated the directional association between NAFLD and the serum creatinine-to-body weight ratio (sCr/bw), a surrogate marker of the muscle mass index, using longitudinal data.

METHODS

We recruited 9662 participants in 2017 and performed follow-up over 4 years. We evaluated whether sCr/bw was related to NAFLD development (Analysis I) and whether NAFLD was associated with a low sCr/bw incidence (Analysis II) using logistic regression models. Furthermore, a random intercept cross-lagged panel model was applied to evaluate the bidirectional association between sCr/bw ratio and NAFLD (Analysis III).

RESULTS

Analysis I demonstrated an association between sCr/bw and incident NAFLD (odds ratio [OR] = 0.160, 95% confidence interval [CI]:0.107-0.232). Analysis II indicated a relationship between NAFLD and subsequent low sCr/bw ratio (OR = 1.524, 95% CI: 1.258-1.846). Analysis III indicated that the standard regression coefficient from sCr/bw to subsequent hepatic steatosis (HS) was -0.053 for βsCr/bw2017 → HS2019 and -0.060 for βsCr/bw2019 → HS2021 and the coefficient from HS to subsequent sCr/bw was -0.093 for βHS2017 → sCr/bw2019 and -0.112 for βHS2019 → sCr/bw2021 (all P < 0.05).

CONCLUSIONS

This study indicated mutual causality between sCr/bw and NAFLD. Considering that sCr/bw is a surrogate marker of muscle mass index, the findings emphasize that NAFLD and low muscle mass form a vicious cycle, which should be taken seriously in clinical practice.

Association between serum ferritin and uric acid levels and nonalcoholic fatty liver disease in the Chinese population

Background

The prevalence of nonalcoholic fatty liver disease (NAFLD) is increasing worldwide. Accumulating evidence suggests that serum ferritin and uric acid (UA) are strongly associated with the risk of NAFLD, but no consensus has been reached.

Objective

We sought to demonstrate the association between serum ferritin, UA levels, and NAFLD risk in a large cohort study.

Methods

We separated 2,049 patients into non-NAFLD and NAFLD groups. The NAFLD group had four subgroups based on serum ferritin and four subgroups based on UA quartile levels. We used binary logistic regression to evaluate the correlation between serum ferritin, UA, and NAFLD. Additionally, an area under the curve (AUC) of receiver operating characteristic analysis (ROC) was used to predict the diagnostic value of combined serum ferritin and UA for NAFLD.

Results

Serum ferritin and UA levels were higher in the NAFLD group compared with the non-NAFLD group. Serum lipid and liver transaminase concentrations were elevated with the increase of serum ferritin and UA. The logistic regression results showed an independent correlation between serum ferritin, UA, and NAFLD. In the NAFLD group, the AUC value of serum ferritin and UA was 0.771.

Conclusions

Increased serum ferritin and UA levels are independent risk factors for NAFLD. Increased serum UA is a stronger risk factor for NAFLD than elevated serum ferritin. Serum ferritin and UA can be important predictors of NAFLD risk.

Serum uric acid is related to liver and kidney disease and 12-year mortality risk after myocardial infarction

Objective

To study the associations of non-alcoholic fatty liver disease (NAFLD), chronic kidney disease (CKD), and serum uric acid (SUA) in patients with post-myocardial infarction (MI) patients, and the relationship of SUA with 12-year mortality risk.

Methods

We included 3,396 patients (60-80 years old, 78% men) of the Alpha Omega Cohort. Multivariable prevalence ratios (PRs) were obtained for the association of NAFLD [fatty liver index (FLI), ≥77 (women) and ≥79 (men)] with CKD [estimated glomerular filtration rate (eGFR), <60 mL/min per 1.73 m2]. We calculated sensitivity and specificity of SUA to detect the (combined) presence and absence of NAFLD and CKD. Cause-specific mortality was monitored from enrolment (2002-2006) through December 2018. Hazard ratios (HRs) for all-cause and cardiovascular disease (CVD) mortality in SUA categories were obtained from multivariable Cox models.

Results

Median baseline FLI was 67 (men, 68; women, 64), and mean ± SD eGFR was 81 ± 20 mL/min per 1.73 m2 (17% with CKD). Sex-specific FLI was associated with higher CKD prevalence (PRtertile3 vs. tertile1, 1.94; 95% confidence interval: 1.57, 2.39). Baseline SUA was 0.36 ± 0.09 mmol/L. With increasing SUA concentrations, specificity for the presence of NAFLD, CKD, or both increased, and sensitivity decreased. During 12 (interquartile range, 9-14) years of follow-up, 1,592 patients died (713 from CVD). HRs ranged from 1.08 (0.88, 1.32) for SUA ≤0.25 mmol/L to 2.13 (1.75, 2.60) for SUA >0.50 mmol/L vs. SUA >0.30-0.35 mmol/L for all-cause mortality. For CVD mortality, HRs ranged from 1.05 (0.77, 1.44) to 2.43 (1.83, 3.25).

Conclusions

NAFLD and CKD were strongly associated, which was reflected by higher SUA concentrations. SUA was a strong predictor of 12-year mortality risk after MI.

Which Comes First, Nonalcoholic Fatty Liver Disease or Arterial Hypertension?

Non-alcoholic fatty liver disease (NAFLD) and arterial hypertension (AH) are widespread noncommunicable diseases in the global population. Since hypertension and NAFLD are diseases associated with metabolic syndrome, they are often comorbid. In fact, many contemporary published studies confirm the association of these diseases with each other, regardless of whether other metabolic factors, such as obesity, dyslipidemia, and type 2 diabetes mellites, are present. This narrative review considers the features of the association between NAFLD and AH, as well as possible pathophysiological mechanisms.

Risk factors of nonalcoholic fatty liver disease in healthy women

We investigated the risk factors of nonalcoholic fatty liver disease (NAFLD) in healthy women. This is a cross-sectional study. Healthy women who underwent physical examination were enrolled. Their basic information and medical history [including age, height, weight, body mass index (BMI)], abdominal ultrasound results, and, serological indexes [including white blood cells, platelet count, fasting blood glucose, triglyceride (TG), total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol (HDLC), uric acid (UA), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and glutamyl transpeptidase] were collected. Univariate and multivariate regression analysis was carried out to screen the risk factors of NAFLD. ALT/AST ratio, and BMI were significantly independent risk factors for the occurrence and severity of NAFLD. In addition, TG/HDLC ratio, and UA level also had significant independent correlation with NAFLD. ALT/AST ratio, BMI, TG/HDLC ratio, and UA are independent risk factors for the occurrence and severity of NAFLD. It is suggested that obesity, hyperlipidemia, hyperuricemia and high transaminase value are closely related to NAFLD. People with such conditions should pay more attention to early screening of NAFLD to avoid disease aggravation and the occurrence and development of other complications. In clinical practice, ALT/AST, BMI, TG/HDLC, and UA level should be closely monitored, so as to facilitate the follow-up management of the disease.

The association between serum uric acid and hypertriglyceridemia: evidence from the national health and nutrition examination survey (2007-2018)

Background

Accumulating evidence suggests that elevated serum uric acid (SUA) may be a risk factor for hypertriglyceridemia (HTG). However, the epidemiological evidence for the association between SUA and HTG is limited. This article aimed to use the data from National Health and Nutrition Examination Survey (NHANES) (2007-2018) database to bridge the research gap.

Methods

This cross-sectional study used data from 10027 adults involved in NHANES from 2007-2018. We designed the exposure variable as SUA and the outcome variable as HTG. The covariates included demographics, questionnaires, laboratory, and examination information. Weighted logistic regression and subgroup analysis were used to explore the independent association between SUA and HTG. Furthermore, interaction tests were also carried out to evaluate the strata differences. Generalized additive models (GAM), smooth curve fittings, and threshold effect analysis were applied to examine the non-linear relationship.

Results

A total of 10027 participants were included, of which 3864 were HTG participants and 6163 were non-HTG participants. After fully adjusting for confounders, weighted multiple logistic regression models revealed a 77% increase in the risk of HTG when each unit of log2-SUA increased. There was also a positive association between elevated log2-SUA and developed risk of HTG in the quartile (Q) groups (Q1 OR: 1.00; Q2 OR: 1.17 [95%CI: 0.95,1.45]; Q3 OR: 1.43 [95%CI: 1.16,1.78]; Q4 OR: 1.68 [95%CI: 1.36,2.08]. The subgroup analysis results remained consistent across strata, with a strong positive correlation between SUA and HTG. Interaction tests showed no dependence on physical activity (PA), gender, BMI, smoking status, alcohol intake, hypertension, and diabetes for this positive association between log2-SUA and HTG (all p for interaction >0.05). The participants' age may impact the strength of the association between SUA and HTG (p for interaction <0.05).

Conclusion

There is a positive association between SUA and HTG in US adults. Considering that SUA may be a risk factor for HTG, individuals diagnosed with HTG should prioritize the daily management of SUA as part of their comprehensive care.

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.

Association Between Serum Uric Acid and Non-Alcoholic Fatty Liver Disease: An Updated Systematic Review and Meta-Analysis

Objective

Recent epidemiological evidence shows that there is an association between serum uric acid (SUA) levels and nonalcoholic fatty liver disease (NAFLD). The purpose of this meta-analysis is to summarize all available evidence and assess the associations between SUA levels and NAFLD.

Methods

Using two databases, Web of Science and PubMed, observational studies were applied from the establishment of the databases to June 2022. We used a random effect model to construct the pooled odds ratio (OR) and 95% confidence interval (CI) to appraise the association between SUA levels and NAFLD. The Begg's test was conducted to appraise publication bias.

Results

A total of 50 studies were included, involving 2,079,710 participants (719,013 NAFLD patients). The prevalence and incidence rates (95% CIs) of NAFLD in the patients with hyperuricemia were 65% (57-73%) and 31% (20-41%), respectively. Compared to participants with lower levels of SUA, the pooled OR (95% CI) of NAFLD in those with higher levels of SUA was 1.88 (95% CI: 1.76-2.00). In the subgroup analyses, we found that SUA levels were positively associated with NAFLD in all subgroups, according to study design, study quality, sample size, sex, comparison, age, or country.

Conclusion

This meta-analysis shows that increased SUA levels are positively associated with NAFLD. The results suggested that reducing SUA levels can be a potential strategy for the prevention of NAFLD.

Registration Number

PROSPERO-CRD42022358431.

Combining serum uric acid and fatty liver index to improve prediction quality of nonalcoholic fatty liver disease

Background

The significant association between serum uric acid (SUA) and nonalcoholic fatty liver disease (NAFLD) is well documented. In this report, we tested the hypothesis that SUA might improve the widely studied fatty liver index (FLI) to predict NAFLD.

Methods

A cross-sectional study was performed in a community of Nanjing, China. The population data on sociodemographics, physical examinations, and biochemical tests were collected from July to September 2018. The associations of SUA and FLI with NAFLD were analyzed using linear correlation, multiple linear regressions, binary logistic analyses, and area under receiver-operating characteristic curve (AUROC).

Results

A total of 3,499 people were included in this study, of which 36.9% had NAFLD. The prevalence of NAFLD increased with the increase of SUA levels (all P <.05). Logistic regression analyses revealed that SUA was significantly associated with an increased risk of NAFLD (all P <.001). The NAFLD predictive value after combining SUA with FLI was superior to FLI, especially in females (AUROC_{SUA + FLI} = 0.911 vs. AUROC_FLI = 0.903, P <.05). The reclassification of NAFLD also significantly improved, based on net reclassification improvement (0.053, 95% confidence interval [CI]: 0.022-0.085, P <.001) and integrated discrimination improvement (0.096, 95% CI: 0.090-0.102, P <.001). A regression formula of this combined algorithm was proposed as: The novel formula = 0.032* waist circumference + 0.303* body mass index + 1.301* natural logarithm of triglyceride + 0.478* natural logarithm of glutamyl transpeptidase + 0.002* SUA- 18.823. At the cutoff value of 13.3, the sensitivity and specificity of this model were 89.2% and 78.4%, respectively.

Conclusions

SUA level was positively associated with NAFLD prevalence. A new formula combining SUA with FLI may serve as a better indicator to predict NAFLD compared to FLI, especially in females.

Outcomes of gout in patients with cirrhosis: A national inpatient sample-based study

BACKGROUND

Hyperuricemia is a prerequisite for the development of gout. Elevated serum uric acid (UA) levels result from either overproduction or decreased excretion. A positive correlation between serum UA levels, cirrhosis-related complications and the incidence of nonalcoholic fatty liver disease has been established, but it is unknown whether hyperuricemia results in worsening cirrhosis outcomes. We hypothesize that patients with cirrhosis will have poorer gout outcomes.

AIM

To explore the link between cirrhosis and the incidence of gout-related complications.

METHODS

This was a cross-sectional study. The national inpatient sample was used to identify patients hospitalized with gout, stratified based on a history of cirrhosis, from 2001 to 2013 via the International Classification of Diseases, Ninth Revision, Clinical Modification codes. Primary outcomes were mortality, gout complications and joint interventions. The χ² test and independent t-test were performed to assess categorical and continuous data, respectively. Multiple logistic regression was used to control for confounding variables.

RESULTS

Patients without cirrhosis were older (70.37 ± 13.53 years vs 66.21 ± 12.325 years; P < 0.05). Most patients were male (74.63% in the cirrhosis group vs 66.83%; adjusted P < 0.05). Patients with cirrhosis had greater rates of mortality (5.49% vs 2.03%; adjusted P < 0.05), gout flare (2.89% vs 2.77%; adjusted P < 0.05) and tophi (0.97% vs 0.75%; adjusted P = 0.677). Patients without cirrhosis had higher rates of arthrocentesis (2.45% vs 2.21%; adjusted P < 0.05) and joint injections (0.72% vs 0.52%; adjusted P < 0.05).

CONCLUSION

Gout complications were more common in cirrhosis. Those without cirrhosis had higher rates of interventions, possibly due to hesitancy with performing these interventions given the higher complication risk in cirrhosis.

Hyperuricemia as an effect modifier of the association between metabolic phenotypes and nonalcoholic fatty liver disease in Chinese population

BACKGROUND

Different metabolic phenotypes may be related to nonalcoholic fatty liver disease (NAFLD), but such association whether modified by serum uric acid levels is unknown. We examined the association between different metabolic phenotypes and NAFLD and further explore whether hyperuricemia could modify this association.

METHODS

A total of 2959 participants (mean age: 55.02 years) with medical checkups were recruited from Tianjin Medical University General Hospital. Participants were categorized into four groups according to their BMI levels and metabolically healthy status: metabolically healthy normal weight (MHNW), metabolically healthy overweight or obese (MHO), metabolically unhealthy normal weight (MUNW), and metabolically unhealthy overweight or obese (MUO). Blood samples (including serum uric acid) were collected from participants after an overnight fast. NAFLD was diagnosed based on abdominal ultrasonography scanning. Data were analyzed using logistic regression models and the interaction effect model.

RESULTS

The prevalence of NAFLD in MHNW, MHO, MUNW, and MUO groups was 9.9% (7.9-12.0%), 42.8% (39.5-46.1%), 36.5% (31.2-41.9%), and 69.7% (66.8-72.6%), respectively. In multi-adjusted logistic models, the ORs (95% CIs) of NAFLD were 5.32 (4.01-7.04) for participants with MHO, 4.51 (3.17-6.40) for those with MUNW, and 13.68 (10.23-18.30) for those with MUO compared to those with MHNW. In the stratified analysis by uric acid levels, the prevalence of NAFLD was significantly higher in participants with MHO, MUNW, and MUO in the hyperuricemia group than those in the normal uric acid group, and the interaction effect of metabolic phenotypes and uric acid on NAFLD was statistical significant (P < 0.05).

CONCLUSIONS

MHO, MUNW, and MUO were associated with higher prevalence of NAFLD. Serum uric acid levels may modify the association between metabolically phenotypes and NAFLD.

Association between Serum Uric Acid and Liver Enzymes in Adults Aged 20 Years and Older in the United States: NHANES 2005-2012

Although the relationship between serum uric acid (SUA) and nonalcoholic fatty liver disease has been widely reported, the relationship between SUA and liver enzymes has rarely been reported. The purpose of this study was to evaluate the association of SUA levels with alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in populations aged 20 years and older in the United States. We analyzed 7165 individuals aged 20 years and older from the National Health and Nutrition Examination Survey (NHANES) in the United States. Weighted multiple linear regression models were used to analyze the relationship between SUA and ALT and AST. A generalized additive model and a smooth curve fitting were used to observe the linear relationship. SUA was positively correlated with ALT and AST. In addition, the overall increasing trend of ALT and SUA was observed across the SUA quartile groups. In the stratified analysis by sex and race, the SUA levels in male, female, Mexican American, and Non-Hispanic White individuals, and those of another race, were positively correlated with ALT and AST. However, the SUA levels in Non-Hispanic Black individuals had a nonlinear relationship with ALT and AST. In individuals aged 20 years and older in the United States (excluding Non-Hispanic Black individuals), SUA levels were positively associated with ALT and AST. Therefore, with a rise in SUA levels, liver function should be monitored or intervened with in people aged 20 years and older in the United States.

Metabolic Dysfunction-Associated Fatty Liver Disease in Newly Diagnosed, Treatment-Naive Hypertensive Patients and Its Association with Cardiorenal Risk Markers

INTRODUCTION

Patients with arterial hypertension frequently present with comorbidities that are associated with increased cardiorenal risk, such as metabolic dysfunction-associated fatty liver disease (MAFLD).

AIMS

Our study aimed to assess the prevalence and the association of MAFLD with cardiorenal risk markers in newly diagnosed, treatment-naïve hypertensive patients.

METHODS

We recruited 281 individuals with new-onset hypertension who were not prescribed any medication. Medical history, clinical examination findings, and laboratory test results were recorded. Liver steatosis was assessed through fatty liver index (FLI) calculation. Patients with FLI ≥ 60 together with one main metabolic abnormality (type 2 diabetes mellitus or overweight/obesity) or at least two metabolic risk abnormalities (increased waist circumference, blood pressure, plasma triglycerides, presence of prediabetes or insulin resistance, decreased plasma high-density lipoprotein) fulfilled the diagnostic criteria for MAFLD.

RESULTS

The prevalence of MAFLD in our study population was 28.7%. Individuals with MAFLD were more frequently male and had increased body mass index. Systolic, diastolic, and pulse pressure values were significantly higher in this group of patients. Moreover, lipid, renal, glucose, and inflammatory markers were considerably deranged in patients with MAFLD. After multivariate regression analysis, uric acid, ferritin, and apoE emerged as independent predictors of MAFLD. Area under receiver operating characteristics curve revealed that uric acid had the greatest diagnostic accuracy, with the ideal cutoff being ≥ 5.2 mg/dl (sensitivity: 77.6%, specificity: 76.3%).

CONCLUSION

MAFLD represents a common comorbidity in hypertensive patients and is associated with markers of cardiorenal risk. Uric acid may be indicative of MAFLD in particular.

Synergistic effect of serum uric acid and body mass index trajectories during middle to late childhood on elevation of liver enzymes in early adolescence: Findings from the Ewha Birth and Growth Study

BACKGROUND/OBJECTIVES

We aimed to determine whether serum uric acid (SUA) and body mass index (BMI) trajectories in childhood have longitudinal association with liver enzymes in adolescence.

METHODS

We conducted a study using data from the Ewha Birth and Growth Cohort. Individual trajectories of SUA (n = 203) and BMI (n = 206) from 5, 7, and 9 years were defined by group-based trajectory modeling. Also, liver function enzymes were collected at 11 to 12 year of age (Aspartate Aminotransferase [AST], Alanine transaminase [ALT], and Gamma-glutamyl transferase [γ-GTP]) (n = 206). Using a generalized linear model, the effects of SUA trajectory and BMI trajectory on liver function enzymes were assessed. We also assessed the interaction effect of SUA and BMI trajectories on liver enzymes.

RESULTS

For trajectory patterns, both SUA and BMI were classified into two distinct groups (High or Low). Both trajectory of SUA and BMI in childhood were positively associated with levels of liver enzymes at 11-12 years of age. The results showed that the combined effect of SUA and BMI trajectories on liver enzymes had a higher means in high-risk group (high SUA-high BMI trajectories group) than in low-risk group (low SUA-low BMI trajectories group) for ALT and γ-GTP, respectively. It remained significant association when adjusted for covariates. In addition, the interaction of BMI and SUA trajectories showed a significant synergistic effect.

CONCLUSION

Elevated childhood SUA and BMI trajectories are associated with increased liver enzymes in beginning of adolescent. This finding suggesting that early interventions in SUA and BMI may need for optimization of liver enzymes as potential marker for development of related disease in later life.

Liver-derived metabolites as signaling molecules in fatty liver disease

Excessive fat accumulation in the liver has become a major health threat worldwide. Unresolved fat deposition in the liver can go undetected until it develops into fatty liver disease, followed by steatohepatitis, fibrosis, cirrhosis, and eventually hepatocellular carcinoma. Lipid deposition in the liver is governed by complex communication, primarily between metabolic organs. This can be mediated by hormones, organokines, and also, as has been more recently discovered, metabolites. Although how metabolites from peripheral organs affect the liver is well documented, the effect of metabolic players released from the liver during the development of fatty liver disease or associated comorbidities needs further attention. Here we focus on interorgan crosstalk based on metabolites released from the liver and how these molecules act as signaling molecules in peripheral tissues. Due to the liver's specific role, we are covering lipid and bile mechanism-derived metabolites. We also discuss the high sucrose intake associated with uric acid release from the liver. Excessive fat deposition in the liver during fatty liver disease development reflects disrupted metabolic processes. As a response, the liver secretes a variety of signaling molecules as well as metabolites which act as a footprint of the metabolic disruption. In the coming years, the reciprocal exchange of metabolites between the liver and other metabolic organs will gain further importance and will help to better understand the development of fatty liver disease and associated diseases.

Age patterns of nonalcoholic fatty liver disease incidence: heterogeneous associations with metabolic changes

BACKGROUND

As the nonalcoholic fatty liver disease (NAFLD) epidemic matures, understanding how metabolic changes in NAFLD development vary over the age distribution is important to guide precise prevention. We aimed to clarify metabolic trends in age-specific NAFLD incidence.

METHODS

We conducted a 4-year longitudinal retrospective cohort study enrolling 10,240 consecutive healthy individuals who received annual physical examination during 2012-2019. Baseline and dynamic changes in metabolism and hepatic steatosis determined with ultrasound were collected and analyzed stratified by age into the following groups: 20-34, 35-49, 50-64, and over 65 years.

RESULTS

Overall, 1701 incident NAFLD participants (16.6%) were identified. Adjusted Cox regression analysis showed that the baseline and increased body mass index were the main risk factors for NAFLD in people ≤ 65 years old. Baseline high-density lipoprotein (HR = 0.56; 95% CI 0.39-0.78) was a protective factor for newly onset NAFLD in the 50-to-64-year-old group, while baseline SBP (HR = 1.03; 95% CI 1.01-1.05), baseline uric acid (HR = 1.04; 95% CI 1.01-1.07), triglyceride increase (HR = 4.76; 95% CI 3.69-6.14), fasting blood glucose increase (HR = 1.32; 95% CI 1.06-1.65) were independently associated with incident NAFLD in over-65-year-old group.

CONCLUSIONS

NAFLD incidence attributable to potentially metabolic risk factors varied substantially across age groups in a cohort of Chinese people. The adoption of age targeted metabolic prevention strategies might reduce the burden of NAFLD.

Citrus Bergamia and Cynara Cardunculus Reduce Serum Uric Acid in Individuals with Non-Alcoholic Fatty Liver Disease

Background and Objectives: Hyperuricemia and liver steatosis are risk factors for cardiovascular diseases and mortality. The use of natural compounds could be a safe and effective alternative to drugs for the treatment of fatty liver and hyperuricemia. Polyphenolic fraction of Citrus Bergamia in association with the extract of Cynara Cardunculus, as nutraceutical, is able to reduce body weight, hepatic steatosis and markers of oxidative stress. Then, we performed a secondary analysis of a double-blind placebo-controlled trial to examine the effects of this nutraceutical on serum uric acid levels in adults with fatty liver. Materials and Methods: The study included 94 individuals with hepatic steatosis. For six weeks, the intervention group was given a nutraceutical (300 mg/day) comprising a Bergamot polyphenol fraction and Cynara Cardunculus extract. The control group received a daily pill of placebo. Serum uric acid, lipids, glucose and anthropometric parameters were assessed at baseline and after 6 weeks. Results: We found a greater reduction in serum uric acid in the participants taking the nutraceutical rather than placebo (−0.1 ± 0.7 mg/dL vs. 0.3 ± 0.7 mg/dL, p = 0.004), and especially in those with moderate/severe hepatic steatosis also after adjustment for confounding variables. In addition, we analysed the two groups according to tertiles of uric acid concentration. Among participants taking the nutraceutical, we found in those with the highest baseline serum uric acid (>5.4 mg/dL) the greater reduction compared to the lowest baseline uric acid (−7.8% vs. +4.9%; adjusted p = 0.04). The stepwise multivariable analysis confirmed the association between the absolute serum uric acid change and nutraceutical treatment (B = −0.43; p = 0.004). Conclusions: A nutraceutical containing bioactive components from bergamot and wild cardoon reduced serum uric acid during 6 weeks in adults with fatty liver. Future investigations are needed to evaluate the efficacy of this nutraceutical in the treatment of hyperuricaemia.

The Additive Values of the Classification of Higher Serum Uric Acid Levels as a Diagnostic Criteria for Metabolic-Associated Fatty Liver Disease

Serum uric acid (SUA) is regarded as an independent risk factor for nonalcoholic fatty liver disease (NAFLD). However, the role of SUA in the new diagnosis flowchart of metabolic-associated fatty liver disease (MAFLD) remains unclear. A cross-sectional study enrolled consecutive individuals with ultrasonography and magnetic resonance imaging−based proton density fat fraction (MRI-PDFF) measurements in the First Affiliated Hospital of Sun Yat-sen University from January 2015 to December 2021. All patients were divided into four groups according to their baseline SUA levels and sex. Of the 3537 ultrasound-diagnosed and 1017 MRI-PDFF-diagnosed MAFLD patients included, the prevalence of severe steatosis determined with ultrasound or MRI-PDFF increased across the serum SUA quartiles. The SUA cutoffs were identified as ≥478 µmol/L and ≥423.5 µmol/L for severe steatosis in male and female MAFLD, respectively. Furthermore, using these cutoff values, patients with higher SUA levels in the NAFLD−non-MAFLD group had higher liver fat contents than those without (16.0% vs. 9.7%, p < 0.001). The lean/normal-weight NAFLD−non-MAFLD patients with higher SUA levels are still at high risk of severe steatosis. This study supports the rationale for SUA being established as another risk factor for metabolic dysfunctions in lean/normal-weight MAFLD.

Serum Uric Acid Levels and Nonalcoholic Fatty Liver Disease: A 2-Sample Bidirectional Mendelian Randomization Study

BACKGROUND

Observational studies have shown that nonalcoholic fatty liver disease (NAFLD) is highly correlated with serum uric acid (SUA). However, these studies have an inherent risk of bias due to reverse causality. Here, we perform a Mendelian randomization (MR) study to investigate causality between SUA and NAFLD.

METHODS

We performed a 2-sample bidirectional MR analysis using summary-level data from genome-wide association studies of SUA (with up to 110 347 individuals) and NAFLD (1483 cases and 17781 controls) in European populations. First, 13 single nucleotide polymorphisms (SNPs) associated with SUA were selected as instruments to estimate the causal effect of elevated SUA levels on the risk of NAFLD using the inverse-variance weighted (IVW) method. Then we performed MR with 3 SNPs as genetic instruments for NAFLD. To test the reliability, further sensitivity analyses were also conducted.

RESULTS

Our MR analyses demonstrated that NAFLD was associated with SUA levels (β = 0.032, P = 0.003). Similar results were obtained using other MR methods and in sensitivity analyses. Genetic predisposition to elevated SUA levels was not associated with NAFLD (IVW MR, odds ratio = 1.02, 95% CI: 0.90-1.15, P = 0.775). Similar results were obtained using other 4 pleiotropy robust MR methods and in sensitivity analyses, excluding 9 SNPs associated with potential confounders.

CONCLUSIONS

Our study supports the causal increased SUA levels by NAFLD, while our study does not confirm a causal association for SUA levels on risk of NAFLD. Further study is needed to interpret the potential mechanisms.

Conjunctional Relationship between Serum Uric Acid and Serum Nickel with Non-Alcoholic Fatty Liver Disease in Men: A Cross-Sectional Study

Serum uric acid (SUA) and heavy metals are closely related to non-alcoholic fatty liver disease (NAFLD). Yet, the conjunctional relationship between SUA and serum nickel (Ni) concentrations with the risk of NAFLD in men has not yet been investigated. Therefore, we designed this cross-sectional study to investigate the association of SUA or serum Ni with NAFLD in men. The cross-sectional study was based on data obtained from a prospective cohort study of common chronic non-communicable diseases in Central China, conducted in Xinxiang city, Central China's Henan Province, between April and June 2017. A total of 1709 male participants completed the physical examination. B-ultrasound was used to examine the liver and to diagnose NAFLD. Binary logistic regression models and restricted cubic splines were performed to estimate the association of the SUA and serum Ni with NAFLD. The prevalence of NAFLD among 1709 male participants was 46.6%. After adjusting for potential confounders, with the highest quartile compared to those with the lowest quartile, SUA (OR = 1.579, 95% CI: 1.140-2.189) and serum Ni (OR = 1.896, 95% CI: 1.372-2.625) were associated with NAFLD, respectively. At the same time, the associations for the second and third SUA quartiles were null. Restricted cubic splines showed a positive linear relationship between serum Ni (ln-transformed) and NAFLD risk. Intriguingly, high SUA and high Ni (OR = 2.370, 95% CI: 1.577-3.597) increased the risk of NAFLD, compared with those with low SUA and low Ni. Our findings demonstrate a positive linear trend between serum Ni concentrations and NAFLD risk. Men with elevated serum Ni had a higher risk of developing NAFLD when compared to those with high SUA. Furthermore, the conjunctional relationship of SUA and serum Ni with NAFLD risk was observed in men.

Fatty liver index for hyperuricemia diagnosis: a community-based cohort study

BACKGROUND

Studies have demonstrated the relationship between the fatty liver index (FLI) and metabolism, while few research reported its relationship with hyperuricemia (HUA). This study aimed to predict HUA by determining the relationship between the baseline FLI and HUA events and by validating the FLI-HUA correlation through follow-up.

METHODS

This study was a community-based cohort study involving 8851 adults in China. We performed anthropometric assessments and analyzed baseline and follow-up blood samples. HUA was defined as a uric acid level of > 420 µmol/L (7 mg/dL).

RESULTS

Patients with HUA had a higher prevalence of diabetes mellitus, lipid metabolism disorders, and hypertension and higher FLI values than those with normal uric acid levels (P < 0.001). Serum uric acid was positively correlated with the FLI (r = 0.41, P < 0.001); the diagnostic cut-off value of FLI for the diagnosis of HUA was 27.15, with a specificity of 70.9% and sensitivity of 79.6%. FLI was an independent risk factor for HUA, with a 1.72-, 2.74-, and 4.80-fold increase in the risk of developing HUA with increasing FLI quartile levels compared with the FLI at quartile level 1 (P < 0.001). After a mean follow-up of 4 years, as the FLI values increased compared with the FLI at quartile level 1, the risk of new-onset HUA increased by 3.10-, 4.89-, and 6.97-fold (P < 0.001).

CONCLUSION

There is a higher incidence of metabolic abnormalities in HUA populations, and FLI is an independent factor that may contribute to HUA development. Therefore, FLI is a potential tool to predict the risk of developing HUA.

A combined association of serum uric acid, alanine aminotransferase and waist circumference with non-alcoholic fatty liver disease: a community-based study

Background

Increasing evidence has supported that serum uric acid (SUA), alanine aminotransferase (ALT) and waist circumference (WC) are associated with the occurrence of non-alcoholic fatty liver disease (NAFLD). However, the combined role of these factors in early screening of NAFLD has not been investigated. We aimed to de lineate this role in a community-based population.

Methods

Binary logistic regression was used to explore the correlations of SUA, ALT and WC with NAFLD risk. The goodness of fit and discriminative ability of the model were evaluated by the Hosmer-Lemeshow test and area under the receiver operating characteristic curve (AUROC), respectively.

Results

Logistic regression analysis indicated that elevated SUA (adjusted odds ratio (OR) = 2.44, 95% confidence interval (CI) [1.76-3.38]), ALT (adjusted OR = 4.98, 95% CI [3.41-7.27]) and WC (adjusted OR = 3.22, 95% CI [2.01-5.16]) were facilitating factors for incident NAFLD after fully adjusted for related confounders. In addition, the risk of NAFLD followed linear trend s with increasing levels of these three indicators (all P _trend < 0.001). The risk assessment model consisting of SUA, ALT, WC and demographics showed useful discrimination by AUROC being 0.825 (95% CI [0.811-0.838]) and good performance of calibration (P = 0.561).

Conclusions

SUA, ALT and WC were all associated with NAFLD, independent of known risk factors. The simple model composed of these indicators showed good performance in the Chinese population, which may be applicable for appraisal of NAFLD risk in primary healthcare.

Comparison of several blood lipid-related indexes in the screening of non-alcoholic fatty liver disease in women: a cross-sectional study in the Pearl River Delta region of southern China

Background

Lipid metabolism disorders play a critical role in the progression of non-alcoholic fatty liver disease (NAFLD). However, the number of studies on the relationships among blood lipid-related indexes and NAFLD is limited, and few studies have emphasized the comparison of blood lipid-related indexes in the same population to identify the optimal index for NAFLD screening. This study aimed to investigate the relationships among several blood lipid-related indexes and NAFLD, and to find the index with the best screening value for NAFLD.

Methods

Based on a general health examination at community health service agencies in the Pearl River Delta region of China in 2015, 3239 women were recruited in this cross-sectional study. The relationships among blood lipid-related indexes and NAFLD were assessed separately by constructing multivariate logistic regression models. Receiver operating characteristic analysis was used to evaluate and compare the screening abilities of the indexes for NAFLD. All data analyses were conducted in SPSS and MedCalc software.

Results

Whether in the crude model or each model adjusted for possible confounding factors, the risk of NAFLD significantly rose with increasing cardiometabolic index (CMI), triglyceride glucose index (TyG), triglycerides (TG) to high-density lipoprotein cholesterol (HDL-C) ratio (TG/HDL-C), total cholesterol (TC) to HDL-C ratio (TC/HDL-C) and low-density lipoprotein (LDL-C) to HDL-C ratio (LDL-C/HDL-C). Moreover, the area under the curve (AUC) of CMI was 0.744, which was better than that of TyG (0.725), TG/HDL-C (0.715), TC/HDL-C (0.650), and LDL-C/HDL-C (0.644) (P < 0.001). In addition, the optimal cut-off points were 0.62 for CMI, 8.55 for TyG, 1.15 for TG/HDL-C, 4.17 for TC/HDL-C, and 2.22 for LDL-C/HDL-C.

Conclusions

CMI is easy to obtain, is a recommended index in the screening of NAFLD in women and may be useful for detecting populations that are at high risk of NAFLD.

Purine metabolites and complex diseases: role of genes and nutrients

PURPOSE OF REVIEW

Purines have several important physiological functions as part of nucleic acids and as intracellular and extracellular signaling molecules. Purine metabolites, particularly uric acid, have been implicated in congenital and complex diseases. However, their role in complex diseases is not clear and they have both beneficial and detrimental effects on disease pathogenesis. In addition, the relationship between purines and complex diseases is affected by genetic and nutritional factors. This review presents latest findings about the relationship between purines and complex diseases and the effect of genes and nutrients on this relationship.

RECENT FINDINGS

Evidence from recent studies show strong role of purines in complex diseases. Although they are causal in only few diseases, our knowledge about their role in other diseases is still evolving. Of all the purines, uric acid is the most studied. Uric acid acts as an antioxidant as well as a prooxidant under different conditions, thus, its role in disease also varies. Other purines, adenosine and inosine have been less studied, but they have neuroprotective properties which are valuable in neurodegenerative diseases.

SUMMARY

Purines are molecules with great potential in disease pathogenesis as either metabolic markers or therapeutic targets. More studies need to be conducted to understand their relevance for complex diseases.

Why Does Hyperuricemia Not Necessarily Induce Gout?

Hyperuricemia is a risk factor for gout. It has been well observed that a large proportion of individuals with hyperuricemia have never had a gout flare(s), while some patients with gout can have a normuricemia. This raises a puzzle of the real role of serum uric acid (SUA) in the occurrence of gout flares. As the molecule of uric acid has its dual effects in vivo with antioxidant properties as well as being an inflammatory promoter, it has been placed in a delicate position in balancing metabolisms. Gout seems to be a multifactorial metabolic disease and its pathogenesis should not rely solely on hyperuricemia or monosodium urate (MSU) crystals. This critical review aims to unfold the mechanisms of the SUA role participating in gout development. It also discusses some key elements which are prerequisites for the formation of gout in association with the current therapeutic regime. The compilation should be helpful in precisely fighting for a cure of gout clinically and pharmaceutically.