Association of elevated serum aminotransferase levels with chronic kidney disease measures: hispanic community health study/study of latinos

Associations of non-invasive indices of liver steatosis and fibrosis with progressive kidney impairment in adults with type 2 diabetes

AIMS

Longitudinal data linking non-alcoholic fatty liver disease to kidney dysfunction in type 2 diabetes (T2D) are limited. This study evaluated the associations of non-invasive indices of liver steatosis and liver fibrosis with kidney impairment, and the mediatory role of the pro-angiogenic factor leucine-rich α-2 glycoprotein 1 (LRG1).

METHODS

T2D adults (n = 2057) were followed for a mean period of 6.1 ± 1.6 years. Baseline liver steatosis [(hepatic steatosis index (HSI) and Zhejiang University index (ZJU)] and liver fibrosis [aspartate transaminase/alanine transaminase ratio (AAR) and BARD] indices derived from composite scoring systems were calculated. Plasma LRG1 levels were quantified using immunoassay. The study outcomes were progressive kidney function decline defined as estimated glomerular filtration rate (eGFR) decline of ≥ 40% and albuminuria progression defined as an increase in albuminuria category.

RESULTS

Cross-sectionally, liver steatosis and liver fibrosis indices were associated with increased albuminuria (urinary albumin/creatinine ratio ≥ 30 µg/mg) and reduced renal function (eGFR < 60 mL/min/1.73 m²) after covariate adjustment, respectively. Approximately 32% of the participants experienced progressive kidney function decline, while 38% had albuminuria worsening over time. Longitudinal analysis revealed that baseline AAR (hazard ratio: 1.56; 95% CI 1.15-2.11) and BARD (hazard ratio: 1.16, 95% CI 1.04-1.28) predicted progressive kidney function decline, partly mediated by LRG1. In contrast, liver steatosis (HSI and ZJU) but not liver fibrosis (AAR and BARD) indices were independently associated with albuminuria progression.

CONCLUSIONS

Increased liver steatosis scores were associated with albuminuria deterioration. Conversely, liver fibrosis indices may be associated with progressive kidney function decline, potentially driven by increased inflammation and angiogenesis.

Nonalcoholic Fatty Liver Disease and Chronic Kidney Disease: Epidemiology, Pathogenesis, and Clinical and Research Implications

Nonalcoholic fatty liver disease (NAFLD) has become the most common cause of chronic liver disease worldwide, affecting up to ~30% of adult populations. NAFLD defines a spectrum of progressive liver conditions ranging from simple steatosis to nonalcoholic steatohepatitis (NASH), cirrhosis, and hepatocellular carcinoma, which often occur in close and bidirectional associations with metabolic disorders. Chronic kidney disease (CKD) is characterized by anatomic and/or functional renal damage, ultimately resulting in a reduced glomerular filtration rate. The physiological axis linking the liver and kidneys often passes unnoticed until clinically significant portal hypertension, as a major complication of cirrhosis, becomes apparent in the form of ascites, refractory ascites, or hepatorenal syndrome. However, the extensive evidence accumulated since 2008 indicates that noncirrhotic NAFLD is associated with a higher risk of incident CKD, independent of obesity, type 2 diabetes, and other common renal risk factors. In addition, subclinical portal hypertension has been demonstrated to occur in noncirrhotic NAFLD, with a potential adverse impact on renal vasoregulation. However, the mechanisms underlying this association remain unexplored to a substantial extent. With this background, in this review we discuss the current evidence showing a strong association between NAFLD and the risk of CKD, and the putative biological mechanisms underpinning this association. We also discuss in depth the potential pathogenic role of the hepatorenal reflex, which may be triggered by subclinical portal hypertension and is a poorly investigated but promising research topic. Finally, we address emerging pharmacotherapies for NAFLD that may also beneficially affect the risk of developing CKD in individuals with NAFLD.

Prevalence of non-alcoholic fatty liver disease in the Russian Ural Eye and Medical Study and the Ural Very Old Study

Information about prevalence and associated factors of non-alcoholic fatty liver disease (NAFLD) has been scarce for the Russian, Eastern European and Central Asian world region. We assessed prevalence and associated factors of NAFLD in two population-based studies (Ural Eye and Medical Study (UEMS), Ural Very Old Study (UVOS)), which were conducted in rural and urban regions in Bashkortostan/Russia and included participants aged 40 + years and 85 + years, respectively. Defining NAFLD by an absence of regular alcohol consumption, and by abnormally high alanine transaminase (ALT) and aspartate transaminase (AST) concentrations or an AST/ALT ratio of > 1.0, 2341 out of 5852 UEMS participants (40.0%; 95% confidence intervals (CI) 38.8, 41.3) had NAFLD. A higher NAFLD prevalence correlated (multivariable analysis) with older age (odds ratio (OR) 1.02; 95%CI 1.01, 1.03; P < 0.001), female sex (OR 1.87; 95%CI 1.58, 2.21; P < 0.001), higher waist-hip circumference ratio (OR 2.64; 95%CI 1.11, 6.27; P = 0.03), lower depression score (OR 0.98; 95%CI 0.96, 0.999; P = 0.04), higher serum concentrations of creatinine (OR 1.004; 95%CI 1.000, 1.008; P = 0.03) and bilirubine (OR 1.009; 95%CI 1.002, 1.015; P = 0.008), lower prothrombin index (OR 0.99; 95%CI 0.985, 0.998; P = 0.01), lower ankle-brachial index (OR 0.49; 95%CI 0.32, 0.75; P = 0.001), higher prevalence of a grain-rich diet (OR 1.88; 95%CI 1.50, 2.36; P < 0.001) and iron deficiency-related anemia (OR 1.61; 95%CI 1.13, 2.29; P = 0.009), and lower prevalence of vigorous leisure activities (OR 0.84; 95%CI 0.72, 0.99; P = 0.04). In the UVOS, NAFLD prevalence (mean: 789/1130; 69.8%; 95%CI 67.1, 72.3) was associated with female sex (OR 2.24; 95%CI 1.66, 3.01; P < 0.001), higher serum concentrations of low-density lipoproteins (OR 1.34; 95%CI 1.17, 1.55; P < 0.001), lower prothrombin index (OR 0.98; 95%CI 0.96, 0.99; P = 0.002), and lower ankle-brachial index (OR 0.03; 95%CI 0.02, 0.29; P = 0.003). The NAFLD prevalence of 40% in the UEMS and 69.8% in the UVOS corresponds to findings obtained in other world regions and shows the importance of NAFLD, including its determinants such as age, sex, waist-hip ratio, serum creatinine concentration, prothrombin index, ankle-brachial index, and lower physical activity.