Gamma-glutamyltransferase and risk of chronic kidney disease: A prospective cohort study

Patients with AMA/anti-sp100/anti-gp210 Positivity and Cholestasis Can Manifest Conditions Beyond Primary Biliary Cholangitis

Background and Aims

The diagnostic value of primary biliary cholangitis (PBC)-specific antibodies in patients with elevated alkaline phosphatase (ALP) and gamma-glutamyl transferase (GGT) levels, and other identifiable causes, was unclear. Our study aimed to determine whether etiological treatments in PBC-specific antibody-positive patients could improve liver biochemical tests, thereby distinguishing them from individuals with PBC.

Methods

We enrolled patients who were positive for PBC-specific antibodies and elevated ALP and/or GGT levels but with other identifiable etiologies. Changes in liver biochemistry following non-ursodeoxycholic acid etiological treatments were monitored.

Results

A total of 155 patients with positive PBC-specific antibodies and elevated ALP and/or GGT levels due to non-PBC diseases were enrolled. Among them, 100 patients were diagnosed with non-PBC liver diseases, mainly metabolic-associated fatty liver disease, drug-induced liver injury, and autoimmune hepatitis. Additionally, 55 patients had non-liver diseases, predominantly connective tissue diseases. The median follow-up duration was 15.9 (4.7-25.6) months. Among 141 patients who completed follow-up after receiving etiological treatments, 85.1% (120/141) showed improvement in ALP and/or GGT levels, with 51.8% (73/141) achieving normalization of both ALP and GGT. However, 68 patients continued to exhibit elevated ALP and/or GGT, with 55 patients displaying isolated GGT elevation and 11 patients showing liver histological changes not consistent with PBC.

Conclusions

PBC-specific antibodies, along with elevated ALP and GGT levels, may occur in various non-PBC diseases. Etiological treatments may improve or even resolve cholestatic biochemistry. For these patients, initiating etiological treatment rather than immediately starting ursodeoxycholic acid therapy would be justified.

Renal Inflammation, Oxidative Stress, and Metabolic Abnormalities During the Initial Stages of Hypertension in Spontaneously Hypertensive Rats

Background: Hypertension is a major cause of mortality worldwide. The kidneys play a crucial role in regulating blood pressure and fluid volume. The relationship between the kidneys and hypertension is complex, involving factors such as the renin-angiotensin system, oxidative stress, and inflammation. This study aims to assess the levels of inflammatory markers, oxidative stress, and metabolic factors in the kidneys, focusing on their potential role in early renal damage and their association with the development of hypertension. Methods: This study was designed to compare the levels of selected inflammatory markers, e.g., interleukins, tumor necrosis factor-α (TNF-α), transforming growth factor, and serine/threonine-protein (mTOR); oxidative stress markers such as malondialdehyde, sulfhydryl group, and glucose (GLC); and metabolic markers among other enzymes, such as alanine transaminase (ALT), aspartate transaminase (AST), hexokinase II (HK-II), and hypoxia-inducible factor-1α (HIF-1α), as well as creatinine in the kidneys of spontaneously hypertensive rats (SHR/NCrl, n = 12) and Wistar Kyoto rats (WKY/NCrl, n = 12). Both juvenile (5 weeks old) and maturing (10 weeks old) specimens were examined using spectrophotometric methods, e.g., ELISA. Results: Juvenile SHRs exhibited reduced renal levels of all studied cytokines and chemokines, with lower oxidative stress and deficits in the mTOR and HK-II levels compared to the age-matched WKYs. Maturing SHRs showed increased renal levels of interleukin-1β (IL-1β), IL-6, IL-18, and TNF-α, alongside elevated carbonyl stress and increased HIF-1α as opposed to their control peers. The levels of all other studied markers were normalized in these animals, except for ALT (increased), ALP, and GLC (both reduced). Conclusions: This study underscores the significant impact of inflammatory, oxidative stress, and metabolic marker changes on renal function. Juvenile SHRs display lower marker levels, indicating an immature immune response and potential subclinical kidney damage that may contribute to hypertension development. In contrast, mature SHRs exhibit chronic inflammation, oxidative dysregulation, and metabolic disturbances, suggesting cellular damage. These changes create a feedback loop that worsens kidney function and accelerates hypertension progression, highlighting the kidneys' crucial role in both initiating and exacerbating this condition.

The synergistic impact of type 2 diabetes and MASLD on cardiovascular, liver, diabetes-related and cancer outcomes

BACKGROUND AND AIMS

We examined the impact of a co-diagnosis of metabolic dysfunction-associated steatotic liver disease (MASLD) and type 2 diabetes (T2D) on patient outcomes.

METHODS

Using TriNetX, a global federated research network (n = 114 million), we undertook two retrospective cohort studies, using time-to-event analysis. Analysis 1 compared MASLD with T2D to MASLD alone; analysis 2 compared T2D with MASLD to T2D alone. Propensity score matching using greedy nearest neighbour (calliper .1) balanced the cohorts (1:1) for significant covariates. Primary outcomes were cardiovascular, liver, diabetes-related, and cancer events over 5 years.

RESULTS

Analysis 1 (n = 95 275): a co-diagnosis of T2D significantly increased the risk of ischaemic heart disease (IHD) (HR 1.39; CI: 1.34, 1.44), ischaemic stroke (HR 1.45; CI: 1.35, 1.56), heart failure (HR 1.42; CI: 1.36, 1.49), atrial fibrillation (HR 1.09; CI: 1.03, 1.16), hepatocellular carcinoma (HR 1.96; CI: 1.69, 2.27), pancreatic cancer (HR 1.25; CI: 1.06, 1.48) and liver-related complications over 5 years from MASLD diagnosis. Analysis 2 (n = 15 208): a co-diagnosis of MASLD significantly increased risk of all-cause mortality (HR 1.11; CI: 1.02, 1.22), IHD (HR 1.181; CI: 1.08, 1.29), hepatocellular (HR 50.31; CI: 6.94, 364.72), pancreatic (HR 1.78; CI: 1.12, 2.84), breast (HR 1.43; CI: 1.09, 1.88) and renal cancer (HR 2.01; CI: 1.24, 3.26), and diabetic neuropathy (HR 1.17; CI: 1.09, 1.27) over 5 years from metformin initiation.

CONCLUSIONS

T2D significantly potentiates the risk of cardiovascular, malignancy and liver-related outcomes in people with MASLD. The effect of MASLD on people with T2D, although less dramatic, still potentiated risk of death, IHD, malignancy and peripheral neuropathy.

Toxicity assessment of 3-O-[6-deoxy-3-O-methyl-β-D-allopyranosyl-(1 → 4)-β-D-oleandropyranosyl]-17β-marsdenin isolated from Gongronema latifolium leaf on selected brain and kidney function indices in mice

The safety of bioactive compounds, especially those isolated from medicinal plants, is a major concern for health authorities, pharmaceutical industries, and the public. Of recent, anti-tumor pregnane glycosides were isolated from Gongronema latifolium leaf, of which the toxicity of one, 3-O-[6-deoxy-3-O-methyl-β-D-allopyranosyl-(1 → 4)-β-D-oleandropyranosyl]-17β-marsdenin (3DMAOM), has not been evaluated. This study, therefore, evaluated the effects of 3DMAOM on selected brain and kidney function indices in mice. Female Swiss albino mice were randomly administered 5% dimethyl sulphoxide and different doses of 3DMAOM (0.5, 1, 2, and 4 mg/kg body weight) for fourteen (14) days, and their blood, brains, and kidneys were collected for biochemical analysis. There was no significant alteration in the activities of alkaline phosphatase (ALP), acetylcholinesterase, creatine kinase, Na+/K+-ATPase, Ca2+/Mg2+-ATPase, and Mg2+-ATPase in the brain of the treated groups compared to control. Also, no significant changes in the activities of ALP, gamma-glutamyltransferase, Na+/K+-ATPase, Ca2+/Mg2+-ATPase, and Mg2+-ATPase in the kidney of the treated groups compared to control. The plasma concentrations of Na+, K+, Cl-, PO43-, creatinine, and urea of mice were not significantly altered at all doses of the 3DMAOM compared to controls. However, the plasma concentration of Ca2+ was significantly reduced (p < 0.05) at all doses of the 3DMAOM, and the plasma concentration of uric acid was significantly reduced (p < 0.05) at 2 mg/kg body weight of the 3DMAOM compared to controls. These findings suggest that 3DMAOM isolated from Gongronema latifolium leaf may not adversely affect brain function but may affect calcium ion homeostasis in subjects.

Baseline and usual triglyceride-glucose index and the risk of chronic kidney disease: a prospective cohort study

Triglyceride-glucose (TyG) index is an emerging marker of adverse cardiometabolic conditions such as cardiovascular disease and type 2 diabetes. The long-term relevance of TyG index to chronic kidney disease (CKD) is uncertain. We aimed to assess the association of TyG index with CKD risk and its utility in risk prediction in a prospective study. The TyG index was calculated using fasting triglycerides and fasting plasma glucose (FPG) levels measured in 2362 men aged 42-61 years with normal kidney function using the formula: Ln (fasting triglycerides [mg/dL] × FPG [mg/dL]/2). Multivariable adjusted hazard ratios (HRs) (95% confidence intervals, CIs) were estimated for CKD. Correction for within-person variability was made using data from repeat measurements of triglycerides and FPG taken 11 years after baseline. Over a median follow-up duration of 17.5 years, 223 CKD cases were recorded. The age-adjusted regression dilution ratio for the TyG index was 0.54 (95% CI, 0.48-0.60). The risk of CKD increased continuously with increasing TyG index across the range 9.3 to 11.6 (p value for nonlinearity<.001). In analysis adjusted for established risk factors, a unit higher TyG index was associated with an increased risk of CKD (HR 1.59, 95% CI 1.24-2.05). Comparing extreme tertiles of the TyG index, the corresponding adjusted HR (95% CI) for CKD was 1.61 (1.15-2.27). Addition of the TyG index to a CKD risk prediction model containing established risk factors improved risk discrimination and reclassification (p value for difference in -2 log likelihood<.001; NRI=47.66%, p=.014; IDI=0.0164, p<.001). Higher TyG index is associated with an increased risk of CKD and improves the prediction and classification of CKD beyond established risk factors. Using single baseline estimations of the TyG index to investigate its association with CKD risk could considerably under-estimate the true association.

Association between serum gamma-glutamyltransferase and early-onset coronary artery disease: a retrospective case-control study

BACKGROUND

Serum gamma-glutamyltransferase (GGT) activity has been proposed as a promising predictor of atherosclerosis-related complications and a prognostic marker for cardiovascular diseases. The objective of this study was to investigate the potential correlation between serum levels of GGT and early-onset coronary artery disease (EOCAD).

METHODS

A retrospective, hospital-based case-control study was conducted, which included 860 patients with EOCAD and gender- and age-matched controls. Serum levels of GGT were measured using the reference measurement procedure on an automatic biochemistry analyser.

RESULTS

The serum GGT levels of patients with EOCAD (34.90 ± 31.44 U/L) were significantly higher than those of the control group (21.57 ± 16.44 U/L, p < .001). Elevated serum levels of GGT were found to be an independent risk factor for EOCAD, with an odds ratio (OR) of 1.021 (95% confidence interval (CI): 1.014-1.029). Additionally, for every quartile increase in serum GGT levels, the risk of developing EOCAD increased by 1.6-fold. Moreover, serum GGT levels were significantly associated with disease severity, with lower GGT levels observed in patients without significant vascular disease (31.74 ± 24.06 U/L) compared to those with two-vessel disease (33.06 ± 25.00 U/L, p = .002) and three-vessel disease (37.75 ± 36.76 U/L, p = .001).

CONCLUSIONS

The results of this study suggest that elevated serum GGT levels are associated with the development of EOCAD, and GGT may be implicated in the pathogenesis of the disease. Further large-scale prospective studies are needed to explore the potential relationship between serum GGT levels and the dynamic development of EOCAD.

The relationship between serum γ-glutamyltransferase (GGT) and diabetic nephropathy in patients with type 2 diabetes mellitus: a cross-sectional study

The relationship between serum γ-glutamyltransferase (GGT) and renal dysfunction is controversial. In this study, we examined the relationship of serum GGT to diabetic nephropathy (DN) in patients with type 2 diabetes mellitus (T2DM). A total of 577 patients with T2DM were enrolled and their basic information and laboratory data were collected and analyzed. The prevalence of DN increased with the elevated serum GGT tertiles. The level of serum GGT in the DN group was higher than in the non-DN groups. Multivariate logistic analysis showed that high GGT was independent risks for DN (OR = 1.041, 95% CIs 1.023-1.059). And the OR of log-transformed serum GGT for DN was 6.190 (95% CIs 4.248-9.021). The OR of DN across increasing tertiles of serum GGT were 1.00, 3.288 (1.851-5.840), and 5.059 (2.620-9.769) (P for trend < 0.001). Stratified receiver operating characteristic (ROC) analysis by gender showed that the area under ROC curve (AUC) value for GGT was 0.781 (0.732-0.825, P < 0.05) in male and was 0.817 (0.761-0.864, P < 0.05) in female. Compared with female, GGT in male showed lower sensitivity (52.86% vs. 82.05%) and higher specificity (90.32% vs. 55.26%). And the AUC value for GGT was greater than creatinine (Cr) and estimated glomerular filtration rate (eGFR) in male and smaller than Cr and eGFR in female, respectively. In Conclusion, there was an independently positive relationship between serum GGT levels and DN, which suggested that elevated GGT was a potential indicator for risk of DN. There were gender differences in the predictive property of GGT for DN.

Cardiovascular risk and kidney function profiling using conventional and novel biomarkers in young adults: the African-PREDICT study

BACKGROUND

Low- and middle-income countries experience an increasing burden of chronic kidney disease. Cardiovascular risk factors, including advancing age, may contribute to this phenomenon. We (i) profiled cardiovascular risk factors and different biomarkers of subclinical kidney function and (ii) investigated the relationship between these variables.

METHODS

We cross-sectionally analysed 956 apparently healthy adults between 20 and 30 years of age. Cardiovascular risk factors such as high adiposity, blood pressure, glucose levels, adverse lipid profiles and lifestyle factors were measured. Various biomarkers were used to assess subclinical kidney function, including estimated glomerular filtration rate (eGFR), urinary albumin, uromodulin and the CKD273 urinary proteomics classifier. These biomarkers were used to divide the total population into quartiles to compare extremes (25th percentiles) on the normal kidney function continuum. The lower 25th percentiles of eGFR and uromodulin and the upper 25th percentiles of urinary albumin and the CKD273 classifier represented the more unfavourable kidney function groups.

RESULTS

In the lower 25th percentiles of eGFR and uromodulin and the upper 25th percentile of the CKD273 classifier, more adverse cardiovascular profiles were observed. In multi-variable adjusted regression analyses performed in the total group, eGFR associated negatively with HDL-C (β= -0.44; p < 0.001) and GGT (β= -0.24; p < 0.001), while the CKD273 classifier associated positively with age and these same risk factors (age: β = 0.10; p = 0.021, HDL-C: β = 0.23; p < 0.001, GGT: β = 0.14; p = 0.002).

CONCLUSION

Age, lifestyle and health measures impact kidney health even in the third decade.

Associations between liver function parameters and poor clinical outcomes in peritoneal dialysis patients

Patients with end-stage renal disease (ESRD) have significantly lower survival rates compared with the general population of the same age. Peritoneal dialysis (PD) is an effective treatment for patients with ESRD, but the clinical outcome of PD patients is still not promising. The survival of PD patients is associated with various clinical factors, and exploring some valid risk predictors may be beneficial for this population. In this review, by integrating the latest research, we summarized the association of some common and novel liver function parameters (ALT, AST, ALP, GGT, serum bilirubin, pre-albumin, albumin, albumin-globulin ratio [AGR], serum ferritin, and hyaluronic acid) with clinical outcomes in PD patients. It may contribute to a better understanding of potential risk factors and help to develop strategies to prevent the disease progression.

The liver-kidney axis: Is serum leptin a potential link in non-alcoholic fatty liver disease-associated chronic kidney disease?

BACKGROUND AND STUDY AIMS

Non-alcoholic fatty liver disease (NAFLD) is an independent risk factor for chronic kidney disease (CKD). Previous studies argued that leptin levels increase significantly with the progression of CKD. But the association between leptin and CKD has not been investigated in patients with NAFLD. Therefore, we conducted this study to establish whether increased leptin level is associated with CKD in NAFLD patients.

PATIENTS AND METHODS

In our prospective study with a follow up period of six months thirty-five teetotaller biopsy-proven NAFLD patients were divided as groups with mild, versus advanced, fibrosis. Liver fibrosis was also assessed with Fibroscan. Serum leptin levels were measured by radioimmunoassay. For insulin resistance we used the homeostasis model assessment method (HOMA-IR). For the kidney function, we used the abbreviated formula Modification of Diet in Renal Disease (MDRD) formula, which estimates GFR. For statistical analysis, Student's-t test, Mann-Whitney test, linear regression-binary logistic regression analyses and the ROC curve analysis were used.

RESULTS

Advanced fibrosis and increased HOMA-IR were risk factors for decreased eGFR. Leptin correlated inversely with advanced fibrosis (p: 0.03) and low leptin was a risk factor for CKD (p: 0.02). In ROC curve analysis, advanced fibrosis and low leptin were risk factors for decreased eGFR (p: 0.007 and 0.004, respectively). Low leptin level was dependently associated with decreased eGFR.

CONCLUSION

Advanced fibrosis in NAFLD patients is a risk factor for CKD. Leptin correlated inversely with advanced fibrosis. Unlike the previous studies, which were not performed in NAFLD patients, we found decreased leptin in NAFLD patients with decreased eGFR. Low leptin level was found to be a dependent predictor for differentiating NAFLD patients with high risk for CKD.

Baseline and usual cardiorespiratory fitness and the risk of chronic kidney disease: A prospective study and meta-analysis of published observational cohort studies

Chronic kidney disease (CKD) is a global public health burden but is largely preventable. Few studies have reported an association between high levels of cardiorespiratory fitness (CRF) and decreased risk of CKD. However, some relevant aspects of the association, such as the dose-response relationship and the long-term relevance of CRF levels to CKD, have yet to be addressed. We, therefore, aimed to quantify the nature and magnitude of the association between CRF and CKD in a cohort of 2099 men aged 42-61 years with normal kidney function at baseline. CRF was directly measured using a respiratory gas exchange analyzer during cardiopulmonary exercise testing. Hazard ratios (HRs) (95% CIs) were estimated for the incidence of CKD. Correction for within-person variability was made using data from repeat measurements of CRF taken 11 years after baseline. A total of 197 CKD events were recorded during a median follow-up of 25.8 years. The age-adjusted regression dilution ratio for CRF was 0.59 (95% CI: 0.53-0.65). The risk of CKD decreased in a graded fashion with increasing CRF. Comparing extreme tertiles of CRF, the HR (95% CI) for CKD was 0.67 (0.46-0.97) following adjustment for several established and emerging risk factors. The corresponding adjusted HR (95% CI) was 0.51 (0.27-0.96) following correction for within-person variability. In a meta-analysis of five population-based cohort studies (including the current study) comprising 32,447 participants and 4,043 CKD cases, the fully-adjusted risk ratios (95% CIs) for CKD comparing extreme tertiles of baseline and long-term CRF values were 0.58 (0.46-0.73) and 0.40 (0.27-0.59), respectively. Findings from a new prospective study and pooled analysis of previous studies plus the new study indicate that high CRF levels are strongly and independently associated with a reduced risk of CKD and consistent with a linear dose-response relationship. Using single baseline measurements of CRF to investigate the association between CRF and CKD risk could considerably underestimate the true association.

Leveraging the South African Diabetes Prevention Programme to screen for chronic kidney disease: an observational study

OBJECTIVE

To evaluate the viability of leveraging an existing screening programme (the South African Diabetes Prevention Programme (SA-DPP)) to screen for chronic kidney disease (CKD), by assessing the yield of CKD cases among those participating in the programme.

DESIGN

Observational study conducted between 2017 and 2019.

SETTING

16 resource-poor communities in Cape Town, South Africa.

PARTICIPANTS

690 participants, aged between 25 and 65 years, identified as at high risk for type 2 diabetes mellitus (T2DM) by the African Diabetes Risk Score.

PRIMARY OUTCOME MEASURE

The prevalence of CKD among those participating in the SA-DPP.

RESULTS

Of the 2173 individuals screened in the community, 690 participants underwent further testing. Of these participants, 9.6% (n=66) and 18.1% (n=125) had screen-detected T2DM and CKD (defined as an estimated glomerular filtration rate (eGFR) of<60 mL/min/1.73 m² and/or albumin-to-creatinine ratio >3 mg/mmol), respectively. Of those with CKD, 73.6% (n=92), 17.6% (n=22) and 8.8% (n=11) presented with stages 1, 2 and 3, respectively. Of the participants with an eGFR <60 mL/min/1.73 m², 36.4% had no albuminuria and of those with normal kidney function (eGFR ≥90 mL/min/1.73 m²), 10.2% and 3.8% had albuminuria stages 2 and 3, respectively. Of those with T2DM and hypertension, 22.7% and 19.8% had CKD, respectively.

CONCLUSION

The fact that almost one in five participants identified as high risk for T2DM had CKD underscores the value of including markers of kidney function in an existing screening programme. By using an opportunistic approach to screen high-risk individuals, those with CKD can be identified and appropriately treated to reduce disease progression.

High Fitness Levels Offset the Increased Risk of Chronic Kidney Disease due to Low Socioeconomic Status: A Prospective Study

BACKGROUND

Socioeconomic status (SES) and cardiorespiratory fitness (CRF) are each independently associated with chronic kidney disease. The interplay among SES, CRF, and chronic kidney disease is not well understood. We aimed to evaluate the separate and joint associations of SES and CRF with chronic kidney disease risk in a cohort of Caucasian men.

METHODS

In 2099 men aged 42-61 years with normal kidney function at baseline, SES was self-reported and CRF was directly measured using a respiratory gas exchange analyzer during cardiopulmonary exercise testing. Hazard ratios (HRs) (95% confidence interval) were estimated for chronic kidney disease.

RESULTS

A total of 197 chronic kidney disease events occurred during a median follow-up of 25.8 years. Comparing low versus high SES, the multivariable-adjusted HR (95% confidence interval) for chronic kidney disease was 1.55 (1.06-2.25), which remained consistent on further adjustment for CRF 1.53 (1.06-2.22). Comparing high versus low CRF, the multivariable-adjusted HR for chronic kidney disease was 0.66 (0.45-0.96), which persisted on further adjustment for SES 0.67 (0.46-0.97). Compared with high SES-high CRF, low SES-low CRF was associated with an increased risk of chronic kidney disease 1.88 (1.23-2.87), with no evidence of an association for low SES-high CRF and chronic kidney disease risk 1.32 (0.85-2.05). Positive additive (relative excess risk due to interaction = 0.31) and multiplicative (ratio of HRs = 1.14) interactions were found between SES and CRF in relation to chronic kidney disease risk.

CONCLUSIONS

In middle-aged and older males, SES and CRF are each independently associated with risk of incident chronic kidney disease. There exists an interplay among SES, CRF and chronic kidney disease risk, with high CRF levels appearing to offset the increased chronic kidney disease risk related to low SES.

Association between the fatty liver index and chronic kidney disease: the population-based KORA study

BACKGROUND

We aimed to evaluate the relationship of fatty liver, estimated by fatty liver index (FLI), with kidney function and chronic kidney disease (CKD) in a German cohort study, given the lack of prospective evidence in Europeans.

METHODS

We included 2920 participants (51.6% women, mean age 56.1 years) from the KORA study, of which 1991 were followed up for an average of 6.4 (± 0.3) years. Kidney function was assessed using the glomerular filtration rate estimated by creatinine (eGFR-cr) or cystatin C (eGFR-cc). We used multiple logistic or linear regressions to evaluate the associations between FLI, kidney function and CKD (eGFR < 60 ml/min per 1.73 m2), and mediation analysis to explore the mediation effects of metabolic factors.

RESULTS

The prevalence of FLI ≥ 60 and CKD were 40.4% and 5.6% at baseline, and 182 participants developed CKD during the follow-up. Cross-sectionally, FLI was significantly inversely associated with eGFR-cc [β, 95%CI: -1.14 (-1.81, -0.47)] and prevalent CKD based on eGFR-cc [OR, 95%CI: 1.28 (1.01, 1.61)], but not with other markers. After adjusting for lifestyle factors, we found a positive association between FLI and incident CKD defined by eGFR-cc or/eGFR-cr, which was attenuated after controlling for metabolic risk factors. Mediation analysis showed that the association was completely mediated by inflammation, diabetes and hypertension jointly.

CONCLUSIONS

The positive association between FLI and CKD incidence was fully mediated by the joint effect of metabolic risk factors. Future longitudinal studies need to explore the chronological interplay between fatty liver, cardiometabolic risk factors and kidney function with repeated measurements.

Crosstalk between kidney and liver in non-alcoholic fatty liver disease: mechanisms and therapeutic approaches

Liver and kidney are vital organs that maintain homeostasis and injury to either of them triggers pathogenic pathways affecting the other. For example, non-alcoholic fatty liver disease (NAFLD) promotes the progression of chronic kidney disease (CKD), vice versa acute kidney injury (AKI) endorses the induction and progression of liver dysfunction. Progress in clinical and basic research suggest a role of excessive fructose intake, insulin resistance, inflammatory cytokines production, activation of the renin-angiotensin system, redox imbalance, and their impact on epigenetic regulation of gene expression in this context. Recent developments in experimental and clinical research have identified several biochemical and molecular pathways for AKI-liver interaction, including altered liver enzymes profile, metabolic acidosis, oxidative stress, activation of inflammatory and regulated cell death pathways. This review focuses on the current preclinical and clinical findings on kidney-liver crosstalk in NAFLD-CKD and AKI-liver dysfunction settings and highlights potential molecular mechanisms and therapeutic targets.

Evaluation of Homocysteine and Gamma-Glutamyl Transferase Concentrations As Markers of Chronic Kidney Disease: An Indian Perspective

Background

Chronic kidney disease (CKD) involves a gradual loss of kidney function over months to years. Oxidative stress plays a critical role in the pathogenesis of CKD. Homocysteine (Hcy), an amino acid derivative, is a known risk factor for oxidative stress and endothelial damage. Gamma-glutamyl transferase (GGT), an enzyme abundant on the cell surface of liver and kidney cells, is raised during oxidative stress. The objectives of this study were to estimate the concentrations of serum Hcy and GGT among CKD patients and healthy controls and to determine whether there is an association between serum Hcy and GGT levels in CKD.

Methodology

A total of 246 participants were needed to meet the calculated sample size. A total of 123 CKD patients meeting the inclusion and exclusion criteria were recruited as cases from the Nephrology outpatient department of our institute. Equal numbers of age- and sex-matched healthy volunteers were recruited as controls. Biophysical profiling of participants was done. Baseline investigations were recorded. A blood sample was collected from each participant and analyzed for GGT and Hcy along with other routine parameters.

Results

Hcy and GGT concentrations were significantly high in CKD patients compared to healthy controls. There was a significant positive correlation between serum GGT and Hcy levels (r = 0.357).

Conclusions

Elevated levels of GGT and Hcy in CKD patients compared to healthy controls demonstrated the oxidative stress associated with the disease. GGT and Hcy can be used as prognostic markers of the disease.

Non-alcoholic fatty liver disease and risk of incident chronic kidney disease: an updated meta-analysis

OBJECTIVE

Studies reported a significant association between non-alcoholic fatty liver disease (NAFLD) and increased risk of chronic kidney disease (CKD). However, whether this risk changes with increasing severity of NAFLD remains uncertain. We performed a meta-analysis of observational studies to quantify the magnitude of the association between NAFLD and risk of incident CKD.

DESIGN

We systematically searched PubMed, Web of Science and Scopus from January 2000 to August 2020 using predefined keywords to identify observational studies with a follow-up duration of ≥1 year, in which NAFLD was diagnosed by blood biomarkers/scores, International Classification of Diseases codes, imaging techniques or biopsy. Data from selected studies were extracted, and meta-analysis was performed using random-effects modelling.

RESULTS

13 studies with 1 222 032 individuals (28.1% with NAFLD) and 33 840 cases of incident CKD stage ≥3 (defined as estimated glomerular filtration rate <60 mL/min/1.73 m2, with or without accompanying overt proteinuria) over a median follow-up of 9.7 years were included. NAFLD was associated with a moderately increased risk of incident CKD (n=10 studies; random-effects HR 1.43, 95% CI 1.33 to 1.54; I2 =60.7%). All risks were independent of age, sex, obesity, hypertension, diabetes and other conventional CKD risk factors. Sensitivity analyses did not alter these findings. Funnel plot did not reveal any significant publication bias.

CONCLUSION

This large and updated meta-analysis indicates that NAFLD is significantly associated with a~1.45-fold increased long-term risk of incident CKD stage ≥3. Further studies are needed to examine the association between the severity of NAFLD and risk of incident CKD.

Carbohydrate antigen 19-9 as a novel prognostic biomarker in distal cholangiocarcinoma

BACKGROUND

Distal cholangiocarcinoma (DCC) presents as one of the relatively rare malignant tumors in the digestive system and has a poor long-term prognosis. Curative resection is currently the most appropriate therapy for patients with DCC because of the lack of effective adjuvant therapies. Therefore, it is important to accurately predict the prognosis for formulating a reasonable treatment plan and avoiding unnecessary surgical trauma.

AIM

To minimize the interference of obstructive jaundice on carbohydrate antigen 19-9 (CA19-9) level by adapting CA19-9 to γ-glutamyltransferase (GGT) as an indicator, to determine the strong associations between CA19-9/GGT and postoperative neoplasm recurrence and long-term outcome of DCC.

METHODS

We enrolled 186 patients who were diagnosed with DCC between January 2010 and December 2019 and performed radical excision with strict criteria as follows in our hospital. Receiver operating characteristic curves were drawn according to preoperative CA19-9/GGT and 1-year survival. Based on this, patients were divided into two groups (group 1, low-ratio, n = 81; group 2, high-ratio, n = 105). Afterwards, by the way of univariate and multivariate analysis, the risk factors influencing postoperative tumor recrudesce and long-term prognosis of patients with DCC were screened out.

RESULTS

Optimum cut-off value of CA19-9/GGT was 0.12. Patients in group 2 represented higher CA19-9 and lymphatic metastasis rate accompanied by lower GGT, when compared with group 1 (P < 0.05). The 1-, 3- and 5-year overall survival rates of patients in groups 1 and 2 were 88.3%, 59.2% and 48.1%, and 61.0%, 13.6% and 13.6%, respectively (P = 0.000). Multivariate analysis indicated that CA19-9/GGT, lymphatic metastasis and tumor differentiation were independent risk factors for tumor recurrence and long-term prognosis of DCC.

CONCLUSION

Elevation of CA19-9/GGT performed better as a biomarker of aggressive carcinoma and predictor of poor clinical outcomes by reducing the effect of obstruction of biliary tract on CA19-9 concentration in patients with DCC.

Expression Status and Prognostic Significance of Gamma-Glutamyl Transpeptidase Family Genes in Hepatocellular Carcinoma

PURPOSE

Gamma-glutamyl transpeptidase (GGT) family genes play crucial roles in the formation and progression of several solid tumors. However, the expression patterns and the prognostic significance of GGT members in hepatocellular carcinoma (HCC) remain unknown. This study was designed to determine the expression profiles of GGT family members in HCC and validate the prognostic value of serum GGT protein in patients with HCC.

METHOD

We comprehensively searched public resources based on the LIHC dataset to determine the expression patterns, prognostic significance, DNA methylation status, immune infiltration, and biological pathways of GGT family genes in HCC. Subsequently, we validated the prognostic value of serum GGT protein in 85 patients with early-stage HCC subjected to curative hepatectomy from the Renmin Hospital of Wuhan University.

RESULTS

Except for GGT1, other GGT family members (GGT5, GGT6, and GGT7) were found to be differentially expressed in primary HCC samples (N = 371) and normal control tissues (N = 50). Furthermore, a positive relationship was not only observed between GGT1 and GGT5 (Spearman coefficient: 0.24, P = 5.143 × 10-6) but also between GGT5 and GGT6 (Spearman coefficient: 0.38, P = 1.24 × 10-13). The expression of GGT1, GGT5, and GGT7 was correlated with overall survival (OS), and GGT7 was associated with disease-free survival (DFS) in patients with HCC. Negative associations between DNA methylation and expression of mRNA were observed for GGT1 (Spearman coefficient: -0.38, P = 6.24e-14), GGT6 (Spearman coefficient: -0.29, P = 1.23e-8), and GGT7 (Spearman coefficient: -0.34, P=6.7e-11). GGT family genes were well correlated with the infiltration levels of immune cells in HCC, especially CD4+ T cells, macrophages, and dendritic cells. Finally, when validated with clinical data from the Renmin cohort, a high expression of serum GGT protein was identified as a strong prognostic element of unfavorable OS (HR = 3.114, P = 0.025), but not of DFS (HR = 1.198, P = 0.05) in patients with HCC subjected to curative hepatectomy.

CONCLUSION

To our knowledge, this is the first comprehensive analysis of the expression patterns and clinical value of GGT family genes in patients with HCC. Our study laid the foundation for the clinical application of the GGT protein in the survival assessment of patients with HCC.

CA19-9 Level to Serum γ-Glutamyltransferase as a Potential Prognostic Biomarker in Patients with Pancreatic Head Carcinoma

BACKGROUND

The aim of this study was to reduce the influence of biliary obstruction on carbohydrate antigen 19-9 level (CA19-9) by introducing the CA19-9 level to serum γ-glutamyltransferase (GGT) ratio as an indicator, and ultimately to reveal the correlation between CA19-9/GGT and the prognosis of patients with pancreatic head carcinoma (PHC).

METHODS

A total of 339 enrolled patients who underwent pancreatoduodenectomy for PHC in Beijing ChaoYang Hospital from January 2010 to December 2019 were analyzed retrospectively. The optimal cut-off value, according to which patients were divided into a low-ratio group (Group 1, n=179) and a high-ratio group (Group 2, n=160), was determined by the ROC curve obtained from preoperative CA19-9/GGT and 1-year survival. Through univariate and multivariate analyses, risk factors for postoperative tumor recurrence and long-term survival were screened out among PHC patients.

RESULTS

The best cut-off value of CA19-9/GGT was 2.07 (area under the curve=0.567, 95% CI 0.498-0.636). Compared with Group 2, Group 1 had lower CA19-9, and higher GGT, total bilirubin (TB) and lymph-node metastasis rate (P<0.05). The 1-, 2- and 3-year disease-free survival rates of patients in Groups 1 and 2 were 68.2%, 42.5% and 28.2%, and 42.2%, 19.3% and 18.3%, respectively (P=0.000), and the 1-, 2- and 3-year overall survival rates were 79.1%, 50.7% and 29.1%, and 56.7%, 22.2% and 17.2%, respectively (P=0.000). Multivariate analysis showed that CA19-9/GGT, portal system invasion and lymph-node metastasis were independent risk factors for postoperative tumor recurrence and long-term survival among patients with PHC.

CONCLUSION

Compared with CA19-9 level alone, CA19-9/GGT plays a more precise role in the evaluation of postoperative tumor recurrence and the long-term prognosis of PHC patients. The lower the ratio, the better the long-term prognosis. The CA19-9/GGT ratio may prove to be a useful biomarker for identifying PHC patients at high risk of early recurrence and unfavorable prognosis.

Non-alcoholic fatty liver and chronic kidney disease: Retrospect, introspect, and prospect

With the growing prevalence of obesity and diabetes in the United States and across the world, a rise in the overall incidence and prevalence of non-alcoholic fatty liver disease (NAFLD) is expected. The risk factors for NAFLD are also associated with the development of chronic kidney disease (CKD). We review the epidemiology, risk factors, genetics, implications of gut dysbiosis, and specific pathogenic mechanisms linking NAFLD to CKD. Mechanisms such as ectopic lipid accumulation, cellular signaling abnormalities, and the interplay between fructose consumption and uric acid accumulation have led to the emergence of potential therapeutic implications for this patient population. Transplant evaluation in the setting of both NAFLD and CKD is also reviewed. Potential strategies for surveillance and management include the monitoring of comorbidities, the use of non-invasive fibrosis scoring systems, and the measurement of laboratory markers. Lastly, we discuss the management of patients with NAFLD and CKD, from preventative measures to experimental interventions.

Baseline liver function tests and full blood count indices and their association with progression of chronic kidney disease and renal outcomes in Aboriginal and Torres Strait Islander people: the eGFR follow- up study

BACKGROUND

Determination of risks for chronic kidney disease (CKD) progression could improve strategies to reduce progression to ESKD. The eGFR Study recruited a cohort of adult Aboriginal and Torres Strait Islander people (Indigenous Australians) from Northern Queensland, Northern Territory and Western Australia, aiming to address the heavy CKD burden experienced within these communities.

METHODS

Using data from the eGFR study, we explored the association of baseline liver function tests (LFTs) (alanine aminotransferase (ALT), alkaline phosphatase (ALP), gamma-glutamyl transpeptidase (GGT), bilirubin and albumin) and full blood count (FBC) indices (white blood cell and red blood cell counts and haemoglobin) with annual eGFR decline and renal outcomes (first of 30% decline in eGFR with a follow-up eGFR < 60 mL/min/1.73 m2, initiation of renal replacement therapy, or renal death). Comparisons of baseline variables across eGFR categories were calculated using analysis of variance and logistic regression as appropriate. Linear and multivariable regression models were used to estimate the annual change in eGFR for changes in FBC indices and LFTs. Cox proportional hazard models were used to estimate the hazard ratio for developing renal outcome for changes in baseline FBC indices and LFTs.

RESULTS

Of 547 participants, 540 had at least one baseline measure of LFTs and FBC indices. The mean age was 46.1 (14.7) years and 63.6% were female. The median follow-up was 3.1 (IQR 2.8-3.6) years. Annual decline in eGFR was associated with low serum albumin (p < 0.001) and haemoglobin (p = 0.007). After adjustment for age, gender, urine albumin/creatinine ratio, diabetes, BMI, CRP, WHR, alcohol consumption, cholesterol and triglycerides, low serum albumin (p < 0.001), haemoglobin (p = 0.012) and bilirubin (p = 0.011) were associated with annual decline in eGFR. Renal outcomes were inversely associated with serum albumin (p < 0.001), bilirubin (p = 0.012) and haemoglobin (p < 0.001) and directly with GGT (p = 0.007) and ALP (p < 0.001). Other FBC indices and LFTs were not associated with annual decline in eGFR or renal outcomes.

CONCLUSIONS

GGT, ALP, bilirubin, albumin and haemoglobin independently associate with renal outcomes. Contrary to findings from other studies, no association was found between renal outcomes and other FBC indices. These findings may help focus strategies to prevent disease progression in this high-risk population.

Gamma-glutamyl transferase variability can predict the development of end-stage of renal disease: a nationwide population-based study

The aim of this study is to investigate whether GGT variability is able to predict the risk of end-stage renal disease (ESRD). The study subjects were Koreans who conducted health exams supported by the Korean National Health Insurance Corporation during 2009-2012 (baseline). After excluding individuals aged < 40 years, heavy alcoholics, or those with histories of chronic liver disease or ESRD, we followed 6,058,995 individuals. We calculated the average successive variability (ASV) of GGT values during the 5 years before the baseline as a parameter of variability. Using Cox proportional analyses, we evaluated the risk of ESRD according to GGT ASV quartiles, defined as the initiation of renal replacement therapy or kidney transplantation, or December 31, 2016. During 38,663,279.3 person-years of follow-up, 12,057 cases of ESRD were identified. Compared with GGT ASV quartile 1, the risk of ESRD was higher in ASV quartiles 3-4 and increased serially, even after adjustment for several metabolic parameters, baseline renal function, presence of comorbidities, low income, and baseline GGT and hemoglobin level. The fully adjusted hazard ratios (95% confidence intervals) of GGT ASV quartiles 3 and 4 were 1.06 (1.01-1.12) and 1.12 (1.06-1.18), respectively. In conclusion, GGT variability is a putative risk factor for ESRD in Koreans.

Association between Non-Alcoholic Fatty Liver Disease and Chronic Kidney Disease: A Cross-Sectional Study

It is unclear whether the link between non-alcoholic fatty liver disease (NAFLD) and chronic kidney disease (CKD) is mediated by common risk factors. We aimed to elucidate the association between NAFLD and CKD using propensity score (PS)-matched analysis. We assessed 3725 Japanese individuals, excluding those with hepatitis B or C infection and men and women who consumed >30 and >20 g/day of alcohol, respectively. Of these, we enrolled 1097 Japanese subjects with NAFLD diagnosed by ultrasonography and 1097 PS-matched subjects without NAFLD. The prevalence of CKD was higher in subjects with NAFLD than in those without NAFLD before PS matching, but there was no significant difference between these groups in terms of CKD prevalence after PS matching. There was no difference in the prevalence of CKD between those with and without NAFLD in the subgroup analyses. Logistic regression analysis demonstrated that obesity, hypertension, and hyperuricemia were independent predictors of CKD, but NAFLD was not independently associated with CKD. In subjects with NAFLD, obesity, hypertension, and hyperuricemia were independent predictors of CKD. Thus, the link between NAFLD and CKD may be mediated by common risk factors. We recommend screening for CKD when patients with NAFLD have the aforementioned comorbidities.

Risk of Kidney Dysfunction IN Nafld

Background:

The timely identification of traditional and non-traditional precursors and risk factors for chronic kidney disease (CKD) (a common systemic disease defined as a decreased kidney function documented by reduced glomerular filtration rate, or markers of kidney damage, or both) is relevant in clinical practice, as CKD increases the risk of end-stage renal disease and other serious comorbidities. A possible relationship between non-alcoholic fatty liver disease (NAFLD) (which is to date the most common chronic disease worldwide) and CKD has recently gained significant attention of researchers.

Methods :

A systematic literature search using appropriate keywords was made in order to identify relevant articles that have investigated the association between NAFLD and CKD.

Results:

Several observational studies and meta-analyses have reported the existence of an independent association between NAFLD and risk of CKD in patients with and without diabetes. However, whilst the association between NAFLD and risk of prevalent CKD is strong across various patient populations, whether NAFLD is independently associated with the development and progression of CKD is still debatable. Moreover, emerging evidence now suggests a potential association between patatin-like phospholipase domain-containing protein-3 (PNPLA3) rs738409 genotype (the most important genetic variant associated to NAFLD) and decreasing kidney function, independent of NAFLD.

Conclusions :

Convincing evidence now indicates that CKD is increased among patients with NAFLD. For this reason, patients with NAFLD should be regularly monitored for renal function and, on the other hand , NAFLD should be considered in all patients with CKD, especially if they are obese or have type 2 diabetes.

Serum Gamma-Glutamyltransferase, Daily Alcohol Consumption, and the Risk of Chronic Kidney Disease: The Kansai Healthcare Study

BACKGROUND

Serum gamma-glutamyltransferase has been recognized as the risk factor of cardiovascular and metabolic diseases. However, the association between serum gamma-glutamyltransferase and the risk of chronic kidney disease is not well known, and no prospective studies have examined separately the relationship of serum gamma-glutamyltransferase with the risk of proteinuria versus that of low estimated glomerular filtration rate (eGFR).

METHODS

We prospectively followed 9,341 Japanese men who did not have low eGFR, proteinuria, or diabetes, and did not take antihypertensive medications at entry for the analysis of proteinuria, and we followed 9,299 men for the analysis of low eGFR. We defined "persistent proteinuria" as proteinuria detected two or more times consecutively and persistently as ≥1+ on urine dipstick at the annual check-up until the end of follow-up. Low eGFR was defined as eGFR <60 mL/min/1.73 m².

RESULTS

During the 11-year observation period, 151 men developed persistent proteinuria and 1,276 men developed low eGFR. In multivariate models, the highest quartile (≥71 IU/L) of serum gamma-glutamyltransferase was independently related to the development of persistent proteinuria (hazard ratio 3.39; 95% confidence interval, 1.92-5.97) compared with the lowest quartile (≤25 IU/L). In joint analysis of alcohol consumption and serum gamma-glutamyltransferase, non-drinkers in the highest tertile (≥58 IU/L) of serum gamma-glutamyltransferase had the highest risk of persistent proteinuria. However, there was no association between serum gamma-glutamyltransferase and low eGFR.

CONCLUSION

In middle-aged Japanese men, elevated serum gamma-glutamyltransferase was independently associated with future persistent proteinuria, but not with low eGFR.

NAFLD as a driver of chronic kidney disease

Non-alcoholic fatty liver disease (NAFLD) and chronic kidney disease (CKD) are worldwide public health problems, affecting up to 25-30% (NAFLD), and up to 10-15% (CKD) of the general population. Recently, it has also been established that there is a strong association between NAFLD and CKD, regardless of the presence of potential confounding diseases such as obesity, hypertension and type 2 diabetes. Since NAFLD and CKD are both common diseases that often occur alongside other metabolic conditions, such as type 2 diabetes or metabolic syndrome, elucidating the relative impact of NAFLD on the risk of incident CKD presents a substantial challenge for investigators working in this research field. A growing body of epidemiological evidence suggests that NAFLD is an independent risk factor for CKD and recent evidence also suggests that associated factors such as metabolic syndrome, dysbiosis, unhealthy diets, platelet activation and processes associated with ageing could also contribute mechanisms linking NAFLD and CKD. This narrative review provides an overview of the literature on: a) the evidence for an association and causal link between NAFLD and CKD and b) the underlying mechanisms by which NAFLD (and factors strongly linked with NAFLD) may increase the risk of developing CKD.

PNPLA3 gene and kidney disease

Chronic kidney disease (CKD) is a disease regularly seen in clinical practice. At present, CKD is described as a change of kidney structure and/or function and it is classified in relation to cause, values of glomerular filtration rate and albuminuria category. Seeing that CKD is closely linked to the development of end-stage renal disease and other comorbidities, the determination of additional independent predictors for CKD is clinically necessary. At present, there is evidence associating non-alcoholic fatty liver disease (NAFLD) with CKD, thereby suggesting that NAFLD patients may require intensive surveillance to reduce their risk of CKD. In 2008, genome-wide association studies documented an association between the variant rs738409 (C > G p.I148M) in the patatin-like phospholipase domain containing 3 (PNPLA3) gene (mainly implicated in the lipid regulation) and the entire spectrum of NAFLD (i.e., liver steatosis, non-alcoholic steatohepatitis, fibrosis, and hepatocellular carcinoma). In the last years, accumulating epidemiological evidence suggests the existence of a relationship between PNPLA3 rs738409 and risk of CKD, indicating that rs738409 may also contribute to the kidney injury. This is of particular scientific interest, as such association may explain, at least in part, the epidemiological association between liver and kidney disease. In this narrative review, we will discuss the accumulating evidence regarding the association between PNPLA3 rs738409 and risk of CKD, the putative biological mechanisms underpinning such relationship, and the possible future perspective.

Nonalcoholic fatty liver disease increases risk of incident advanced chronic kidney disease: a propensity-matched cohort study

BACKGROUND

As the prevalence of nonalcoholic fatty liver disease (NAFLD) escalates, understanding its potential impact on the development of chronic kidney disease (CKD) is needed.

OBJECTIVE

To determine the longitudinal association of NAFLD with the development of advanced CKD in the United States.

METHODS

A retrospective cohort analysis of the Truven Health MarketScan Database (2006-2015) was conducted. We used Cox proportional hazards models to compare the risk of developing CKD stages 3-5 in patients with NAFLD versus non-NAFLD, identified by ICD-9 codes, after 1:3 propensity score (PS) matching.

RESULTS

In a cohort of 262 619 newly diagnosed patients with NAFLD and 769 878 PS (1:3)-matched non-NAFLD patients, we identified 5766 and 8655 new advanced (stage 3-5) CKD cases, respectively. The crude CKD incidence rate was 8.2 and 5.5 per 1000 person-years in NAFLD and non-NAFLD groups, respectively. In multivariable Cox model, patients with NAFLD had a 41% increased risk of developing advanced CKD compared with non-NAFLD patients [adjusted hazard ratio (aHR), 1.41; 95% confidence interval (CI), 1.36-1.46]. In the sensitivity analysis adjusting for time-varying covariates after NAFLD diagnosis, NAFLD persisted as a significant CKD risk factor (aHR, 1.58; 95% CI, 1.52-1.66) and the association remained significant when stratified by age, gender and pre-existing comorbidities. The risk of CKD increased in NAFLD with compensated cirrhosis (aHR, 1.47; 95% CI, 1.36-1.59) and decompensated cirrhosis (aHR, 2.28; 95% CI, 2.12-2.46).

CONCLUSION

Nonalcoholic fatty liver disease was independently associated with an increased risk of advanced CKD development suggesting renal function screening and regular monitoring are needed in this population.

Nonalcoholic fatty liver disease increases risk of incident chronic kidney disease: A systematic review and meta-analysis

BACKGROUND

Recent studies examined the prognostic impact of nonalcoholic fatty liver disease (NAFLD) on the risk of incident chronic kidney disease (CKD). However, the extent to which NAFLD may confer risk of incident CKD is uncertain. We performed a meta-analysis of relevant studies to quantify the magnitude of the association between NAFLD and risk of incident CKD.

METHODS

We searched PubMed, Scopus and Web of Science from January 1, 2000 to August 31, 2017 using pre-defined keywords to identify large observational cohort studies with a follow-up duration of at least 1year, in which NAFLD was diagnosed by biochemistry, fatty liver index or ultrasonography. No studies with biopsy-proven NAFLD were available for the analysis. Data from selected studies were extracted, and meta-analysis was performed using random-effects modeling.

RESULTS

A total of 9 observational studies with 96,595 adult individuals (34.1% with NAFLD) of predominantly Asian descent, and 4653 cases of incident CKD stage ≥3 (i.e., defined as occurrence of estimated glomerular filtration rate<60ml/min/1.73m2, with or without accompanying overt proteinuria) over a median period of 5.2years were included in the final analysis. Patients with NAFLD had a significantly higher risk of incident CKD than those without NAFLD (random-effects hazard ratio [HR] 1.37, 95% CI 1.20-1.53; I2=33.5%). Patients with more 'severe' NAFLD (according to ultrasonography and non-invasive fibrosis markers) were also more likely to develop incident CKD (n=2 studies; random-effects HR 1.50, 95% CI 1.25-1.74; I2=0%); this risk appeared to be even greater among those with ultrasound-diagnosed NAFLD and a high-intermediate NAFLD fibrosis score (n=1 study; random-effects HR 1.59, 95% CI 1.31-1.93). Sensitivity analyses did not alter these findings. Funnel plot and Egger's test did not reveal significant publication bias.

CONCLUSIONS

This largest and most updated meta-analysis to date shows that NAFLD (detected by biochemistry, fatty liver index or ultrasonography) is associated with a nearly 40% increase in the long-term risk of incident CKD. However, the observational nature of the eligible studies does not allow for proving causality. Our findings pave the way for future large, prospective, histologically-based studies.