Metabolic syndrome and uric acid nephrolithiasis: insulin resistance in focus

Elevated triglyceride glucose index is associated with advanced cardiovascular kidney metabolic syndrome

The cardiovascular kidney metabolic (CKM) syndrome is a dynamic geriatric condition that has received limited research attention regarding its potential associations with the triglyceride glucose (TyG) index. This study aims to explore the potential association between the TyG index and advanced CKM syndrome. Data for this cross-sectional study were obtained from the National Health and Nutrition Examination Survey (NHANES) conducted between 2011 and 2018. The association between the TyG index and the risk of advanced CKM syndrome was investigated using multivariable logistic regression models. Additionally, a restricted cubic spline (RCS) analysis was employed to assess the dose-response relationship between the TyG index and the risk of advanced CKM syndrome. A total of 7904 participants were included in this study, with a mean TyG index of 5.04 ± 0.41. The prevalence of advanced CKM syndrome among the participants was 14.85%. Our findings indicated that as the TyG index quartiles increased, the risk of advanced CKM syndrome also increased. The results from the three regression analysis models indicated a positive association between the continuous TyG index and advanced CKM syndrome. Furthermore, the quartiles of the TyG index were significantly associated with an increased prevalence of advanced CKM syndrome in the fully adjusted models (TyG index Q4 vs. Q1, OR = 1.94, 95% CI 1.37-2.75, P < 0.001). The results of the RCS analysis indicated a linear and positive association between the TyG index and advanced CKM syndrome. The results indicated that elevated TyG index is associated with an increased prevalence of advanced CKM syndrome. This suggests that the TyG index may be a useful tool for assessing the risk of advanced CKM syndrome.

A nomogram to predict "pure" vs. "mixed" uric acid urinary stones

PURPOSE

Uric acid stones (UAS) can be treated non-invasively by oral chemolysis. However, it is crucial to identify individuals who are most likely to benefit from this approach, specifically, patients with pure UAS. The aim of this study was to develop a nomogram that can differentiate between pure and mixed UAS.

METHODS

A retrospective analysis of demographic, clinical and stone composition data of patients with a predominant UAS composition (≥ 50%) treated between 2014 and 2022.

RESULTS

A total of 135 patients were included in the analysis, 37.8% had mixed UAS (50-90% UA) and 62.2% had pure UAS (≥ 95% UA). The mean stone density and the percentage of radiopaque stones in the pure UAS group were significantly lower than those in the mixed UAS group (450 Hounsfield Units [HU] vs. 600 HU, and 24% vs. 58%, respectively). A stepwise multivariate logistic regression revealed that lower stone density, bigger size, decreased stone opacity and older age are predictive variables for pure UAS. Accordingly, a nomogram was generated with a receiver operating characteristic (ROC) curve that showed an area under the curve (AUC) of 0.78. A patient with a total score of 156 has a probability of > 95% for pure UAS.

CONCLUSION

Imaging and demographic data can be used to identify patients with pure UAS. The nomogram may be useful for counseling patients regarding oral chemolysis. Future validation of the nomogram with a different data set is required to assess its efficacy.

Self-control study of multi-omics in identification of microenvironment characteristics in urine of uric acid stone

The aim of this study is to perform proteomic and metabolomic analyses in bilateral renal pelvis urine of patients with unilateral uric acid kidney stones to identify the specific urinary environment associated with uric acid stone formation. Using cystoscopy-guided insertion of ureteral catheters, bilateral renal pelvis urine samples are collected. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is employed to identify differentially expressed proteins and metabolites in the urine environment. Differentially expressed proteins and metabolites are further analyzed for their biological functions and potential metabolic pathways through Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. In the urine from the stone-affected side, eight differential proteins were significantly upregulated, and six metabolites were dysregulated. The uric acid stone urinary environment showed an excess of α-ketoisovaleric acid and 3-methyl-2-oxovaleric acid, which may contribute to the acidification of the urine. Functional and pathway analyses indicate that the dysregulated metabolites are mainly associated with insulin resistance and branched chain amino acid metabolism.

The associations of insulin resistance, obesity, and lifestyle with the risk of developing hyperuricaemia in adolescents

BACKGROUND

Hyperuricaemia is common among obese children and adolescents, and is closely related to insulin resistance. The aim of this study was to explore the relationships between youth insulin resistance and hyperuricaemia, as well as their relationships with lifestyle factors in youths, to provide early guidance on the risk factors for hyperuricaemia in adolescents.

METHODS

This study included 233 adolescents aged 10 to 20 years. Insulin resistance was evaluated via the homeostasis model assessment-insulin resistance (HOMA-IR) method. Binary logistic regression analysis was used to assess the associations of HOMA-IR with hyperuricaemia status and serum uric acid (UA) levels. The participants were subsequently divided into two groups, the noninsulin resistant group (HOMA-IR ≤ 3.2) and the insulin resistant group (HOMA-IR > 3.2), to further explore the factors that may affect the serum UA level. Finally, the predictive ability of different indicators of hyperuricaemia was evaluated via the ROC curve.

RESULTS

Binary logistic regression analysis revealed a significant increase in the risk of developing hyperuricaemia for individuals with elevated HOMA-IR (p < 0.001) and insulin resistance (p < 0.01). Spearman's correlation analysis revealed a significant positive linear correlation between HOMA-IR and serum UA levels (r = 0.4652, p < 0.001). Among insulin-resistant adolescents, UA levels were positively correlated with weight ratings, frequency of staying up late, and sugary beverages intake. Notably, individuals who engaged in 1-3 h of weekly exercise had the lowest UA levels. The area under the ROC curve for HOMA-IR was 0.847 (cut-off value = 2.165, p < 0.001), and the optimal prediction model included HOMA-IR, BMI z-score, and other lifestyle factors (AUC: 0.870, p < 0.001)).

CONCLUSION

HOMA-IR was identified as an independent risk factor for the development of hyperuricaemia and could be used as a sensitive indicator for the prediction its development in adolescents. In insulin-resistant adolescents with hyperuricaemia, maintaining normal weight, engaging in physical exercise for 1-3 h per week, avoiding staying up late and limiting sugary beverages intake are recommended to reduce the prevalence of hyperuricaemia among adolescents.

Exploring the Relationship Between Different Obesity Metabolism Indices and Hyperuricemia in Patients with Hypertension and Coronary Heart Disease

Background

Previous studies have established a strong association between obesity, high metabolism, and the development of hyperuricemia. However, the relationship between obesity metabolism indices and hyperuricemia in high-risk patients with hypertension and coronary heart disease (CHD) remains unclear. The purpose of this study was to investigate this relationship in patients with both hypertension and CHD, and to identify the obesity metabolism index with the best diagnostic value.

Methods

A two-center study encompassed 6344 participants with hypertension and CHD. Multiple logistic regression was utilized to examine the correlation between six obesity metabolism indices and hyperuricemia, with restricted cubic spline (RCS) analysis to identify non-linear relationships. Diagnostic value was assessed via receiver operating characteristic (ROC) curves and decision curve analysis (DCA).

Results

Multivariable logistic regression revealed a significant correlation between increased obesity metabolism indices and hyperuricemia. Furthermore, RCS analysis revealed a nonlinear dose-response relationship (P for nonlinear < 0.001). Moreover, ROC and DCA results showed that METS-VF index, which combined visceral obesity and metabolic parameters, became the most reliable diagnostic tool.

Conclusion

The study underscores a strong association between elevated obesity metabolism indices and hyperuricemia in patients with hypertension and CHD. The METS-VF index, amalgamating visceral obesity and metabolic parameters, emerged as the most reliable diagnostic tool.

Association between insulin resistance indices and kidney stones: results from the 2015-2018 National Health and Nutrition Examination Survey

Objective

To explore the association between representative insulin resistance (IR) indices and the risk of kidney stone disease in an American adult population. The representative IR indices referred to metabolic score for IR (METS-IR), triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio, triglyceride glucose-body mass index (TyG-BMI), visceral adiposity index (VAI), and homeostatic model assessment of IR (HOMA-IR).

Methods

We investigated adult participants who joined the 2015-2018 National Health and Nutrition Examination Survey (NHANES) and reported kidney stone histories. Weighted proportions, multivariable regression analysis, and restricted cubic splines were used to evaluate the associations between IR indices and kidney stones after their adjustment for gender, age, race, education, smoking status, alcohol drinking frequency, hypertension and diabetes status, physical activity level, water intake, and levels of calcium, cholesterol, and uric acid.

Results

A total of 19,225 participants were included. The weighted prevalence of kidney stone was 11.1%. A multivariable logistic regression model showed a dose-response relationship between the METS-IR and kidney stone [odds ratio (OR) = 1.02, 95% confidence interval (CI) (1.01, 1.04), p < 0.01]. A similar relationship was observed between the TyG-BMI and kidney stone after full adjustment [OR = 1.0, 95% CI (1.0, 1.01), p < 0.001]. Sex-stratified analyses revealed that the association between METS-IR and nephrolithiasis [OR = 1.03, 95% CI (1.01, 1.05), p < 0.01], and the association between TyG-BMI and nephrolithiasis [OR = 1.01, 95% CI (1.0, 1.01), p <0.001] was significant among the male participants in the fully adjusted model. Moreover, a significant association was found between the METS-IR levels and nephrolithiasis [OR = 1.03, 95% CI (1.01, 1.06), p < 0.01], and between the TyG-BMI levels and nephrolithiasis [OR = 1.01, 95% CI (1.0, 1.01), p < 0.05] among the diabetic participants after full adjustment. Furthermore, a potential nonlinear association was found between other IR indices (i.e., TG/HDL-C, VAI, and HOMA-IR) and the risk of kidney stone disease.

Conclusion

Higher METS-IR and TyG-BMI levels were associated with a higher risk of nephrolithiasis. Future investigations are required to identify the role of IR in the progress of kidney stone formation and to propose prevention measures and health guidelines.

Association between metabolic dysfunction-associated steatotic liver disease and risk of urolithiasis: an updated systematic review and meta-analysis

Epidemiological studies have reported an association between metabolic dysfunction-associated steatotic liver disease (MASLD) and the risk of urolithiasis. However, the magnitude of the risk and whether this risk varies with the severity of MASLD remains uncertain. We performed a meta-analysis of observational studies to quantify the magnitude of the association between MASLD and urolithiasis. We systematically searched PubMed, Scopus, and Web of Science from database inception to March 31, 2024, using predefined keywords to identify relevant observational studies in which imaging methods or survey questionnaires diagnosed MASLD and urolithiasis. Meta-analysis was performed using random-effects modelling. We identified seven cross-sectional studies and one prospective cohort study with aggregate data on 248,936 adults from different countries. MASLD was significantly associated with an increased risk of prevalent urolithiasis (pooled random-effects odds ratio 1.87, 95% CI 1.34-2.60; I2 = 91%). This association remained significant in those studies whose results were adjusted for age, sex, ethnicity, obesity, diabetes, and other potential confounders. There was a positive graded association between the ultrasonographic severity of MASLD and urolithiasis. Meta-analysis of the single prospective cohort study showed that MAFLD was not associated with risk of developing incident urolithiasis (pooled random-effects hazard ratio 1.08, 95% CI 0.90-1.30), although a significant association was reported in men. Sensitivity analyses did not modify these findings. The funnel plot did not reveal any significant publication bias. This updated meta-analysis provides evidence for a significant association between MASLD and the presence of urolithiasis. Whether MASLD is associated with a higher risk of developing incident urolithiasis remains to be established.

Association between the atherogenic index of plasma and kidney stones: a nationally representative study

PURPOSE

The atherogenic index of plasma (AIP) is a novel comprehensive lipid index. We aimed to investigate a possible relationship between AIP index and kidney stones in US adults.

METHODS

This cross-sectional study was conducted among adults with complete AIP index and questionnaire records on kidney stones from the National Health and Nutrition Examination Survey (NHANES) spanning from 2007 to 2018. The AIP index served as the exposure variable, defined as the logarithm of the ratio between triglycerides (TG, mmol/L) and high-density lipoprotein cholesterol (HDL-c, mmol/L). Self-reported history of kidney stones was utilized as the outcome variable. The independent relationship between AIP index and the risk of kidney stones was fully assessed.

RESULTS

A total of 14,833 participants were included in this study, with an average AIP index of -0.07 ± 0.01. The proportion of kidney stones progressively increased with higher AIP index tertile intervals (7.33% vs. 9.97% vs. 12.57%, P < 0.001). Furthermore, AIP index was found to be independently associated with the risk of kidney stones after adjusting for confounding factors (OR = 1.32, 95% CI 1.08-1.61, P = 0.006). Restricted cubic spline (RCS) analysis confirmed the robustness of our results. There was no significant interaction observed based on subgroup analysis stratified by age, gender, race, body mass index (BMI, kg/m2), smokers, diabetes, hypertension, and cardiovascular disease (P for interaction > 0.05).

CONCLUSIONS

The AIP index may be a potential epidemiological tool to quantify the role of dyslipidemia in the risk of kidney stones in US adults.

Effect of gout and diabetic kidney disease on renal cancer development in Korea

Background

Chronic kidney disease (CKD) and gout are risk factors for renal cancer. We analysed the effects of comorbid diabetic kidney disease and gout on renal cancer.

Methods

This retrospective cohort study enrolled 847 884 patients with type 2 diabetes mellitus (T2DM) who underwent health assessments provided by the Korean National Health Insurance Service in 2009. Based on CKD occurrence (glomerular filtration rate <60 ml/min/1.73 m2) and gout (two outpatient visits or one hospitalization within 5 years), patients were classified into four groups: CKD-Gout- (87.5%), CKD-Gout+ (2.5%), CKD+Gout- (9.3%) and CKD+Gout+ (0.7%). Patients with incident renal cancer (International Classification of Diseases code C64) were followed up until December 2018.

Results

Renal cancer was diagnosed in 2376 patients (0.3%). Renal cancer incidence increased in sequential order of CKD-Gout- [0.29/1000 person-years (PY), CKD+Gout- and CKD-Gout+ (0.44 and 0.48/1000 PY, respectively) and CKD+Gout+ (1.14/1000 PY). Comorbid gout increased renal cancer risk depending on CKD occurrence {hazard ratio [HR] 1.28 [95% confidence interval (CI) 1.04-1.58 among those without CKD; HR 1.95 [95% CI 1.45-2.63] among those with CKD; P-value for interaction = 0.024}. The interaction was significant, particularly in men and patients with a shorter diabetes duration (<5 years) and lesser medication use (no insulin or fewer than three classes of oral hypoglycaemic agents).

Conclusions

CKD and gout individually contributed to renal cancer incidence, and the risk is further increased when gout coexists with CKD. Screening for gout and appropriate management of CKD at an early T2DM stage may be beneficial.

Association between triglyceride glucose index and hyperuricemia: a new evidence from China and the United States

Background

Hyperuricemia (HUA) is a glo\bal public health problem. The etiology of HUA is complex and efficient and accurate assessment metrics are still lacking when conducting large-scale epidemiologic screening. The aim of this study was to evaluate the association of the triglyceride glucose (TyG) index, TyG-body mass index (BMI), TyG-waist-to-height ratio (WHtR) with the risk of HUA.

Methods

Based on data collected from the National Health and Nutrition Examination Survey (NHANES) in the United States and the China Health and Aging Longitudinal Study (CHARLS) in China, a total of 14,286 U.S. adults and 4,620 Chinese adults were included in the analysis. The study examined the levels of TyG, TyG-BMI, TyG-WHtR, and TyG-WC. Multivariate logistic regression was utilized to investigate the relationships between these variables and hyperuricemia (HUA), separately. Additionally, the study used restricted cubic splines (RCS) to explore the linear associations of TyG, TyG-BMI, TyG-WHtR, TyG-WC, and HUA, separately.

Results

The NHANES results showed that TyG [Q2, 1.58(1.26, 1.98); Q3, 2.36 (1.94, 2.88); Q4, 3.21 (2.61, 3.94)], TyG-BMI [Q2, 2.14 (1.74, 2.65); Q3, 3.38 (2.74, 4.17); Q4, 6.70 (5.55, 8.02)], TyG-WHtR [Q2, 1.92 (1.56, 2.36); Q3, 3.14 (2.56, 3.85); Q4, 6.28 (5.12, 7.69)], TyG-WC [Q2, 2.32 (1.85, 2.90); Q3, 3.51 (2.84, 4.34); Q4, 7.32 (5.95, 9.02)] were identified as risk factors for hyperuricemia (HUA). Similarly, the CHARLS results, when fully adjusted for covariates, indicated that TyG [Q4, 2.36 (1.08, 5.15)], TyG-BMI [Q3, 2.60 (1.05, 6.41); Q4, 3.70 (1.64, 8.32)], TyG-WHtR (Q4, 2.84 (1.23, 6.55), TyG-WC [Q4, 2.85 (1.23, 6.5)] were also risk factors for HUA. The predictive ability of each indicator for the risk of developing HUA was stronger in women than in men. Furthermore, there was an observed nonlinear relationship between TyG, TyG-BMI, TyG-WHtR, TyG-WC, and HUA in both the NHANES and CHARLS datasets (P-nonlinearity < 0.05).

Conclusion

These findings suggest that TyG, TyG-BMI, TyG-WHtR and TyG-WC are associated with an increased risk of HUA. They are potential indicators for screening HUA status in the general population in China and the United States.

Association of serum uric acid with women's ovarian reserve: observational study and Mendelian randomization analyses

OBJECTIVE

To investigate the association between serum uric acid and women's ovarian reserve.

DESIGN

Retrospective observational study and Mendelian randomization study.

SETTING

University-affiliated in vitro fertilization center.

PATIENTS

Observational analyses were undertaken using data from 8,257 women with infertility who finished their first in vitro fertilization treatments between May 2017 and December 2021. Mendelian randomization analyses were based on genome-wide association summary statistics from several biobanks of predominantly European ancestries.

INTERVENTIONS

Observational study involved testing log2 transformed serum uric acid levels (for linear, negative regression, and logistic regression analyses); original uric acid levels (for nonlinear association analyses). Mendelian randomization study involved testing genetically predicted uric acid levels.

MAIN OUTCOME MEASURES

Biomarkers including antimüllerian hormone, basal antral follicle count, follicle-stimulating hormone, luteinizing hormone, ratio of follicle-stimulating hormone to luteinizing hormone, estradiol; indices of ovarian response to stimulation including poor ovarian response according to different criteria and oocyte yield.

RESULTS

In retrospective observational study, all ovarian reserve-related outcomes demonstrated significant differences across serum uric acid quartiles. A two-fold uric acid increase was associated with increased antimüllerian hormone (adjusted β = 0.69; 95% confidence interval [CI], 0.43-0.95), antral follicle count (adjusted incidence rate ratio = 1.10, 95% CI, 1.05-1.14), luteinizing hormone (adjusted β = 0.53, 95% CI, 0.28-0.78), decreased risks of Bologna poor ovarian response (adjusted odds ratio = 0.97; 95% CI, 0.95-0.99) and groups 2-4 Poseidon poor ovarian response (group 2: 0.63, 0.56-0.71; group 3: 0.71, 0.65-0.78; group 4: 0.50, 0.46-0.55), whereas an increased risk of group 1 (1.26, 1.13-1.41). Nonlinear analyses showed a common inflection point at 320-340 μmol/L of uric acid. Interactions between uric acid and antimüllerian hormone and antral follicle count were presented in association with oocyte yield. Mendelian randomization results suggested a significant association between genetically predicted uric acid levels and antimüllerian hormone levels (β = 0.08; 95% CI, 0.04-0.12) but none for uric acid in relation to polycystic ovarian syndrome or other related hormones.

CONCLUSION

Higher uric acid levels were associated with better ovarian reserve and increased levels of antimüllerian hormone albeit an increased risk of unexpected poor ovarian response.

Gut microbiota in insulin resistance: a bibliometric analysis

Background

Insulin resistance (IR) is considered the pathogenic driver of diabetes, and can lead to obesity, hypertension, coronary artery disease, metabolic syndrome, and other metabolic disorders. Accumulating evidence indicates that the connection between gut microbiota and IR. This bibliometric analysis aimed to summarize the knowledge structure of gut microbiota in IR.

Methods

Articles and reviews related to gut microbiota in IR from 2013 to 2022 were retrieved from the Web of Science Core Collection (WoSCC), and the bibliometric analysis and visualization were performed by Microsoft Excel, Origin, R package (bibliometrix), Citespace, and VOSviewer.

Results

A total of 4 749 publications from WoSCC were retrieved, including 3 050 articles and 1 699 reviews. The majority of publications were from China and USA. The University Copenhagen and Shanghai Jiao Tong University were the most active institutions. The journal of Nutrients published the most papers, while Nature was the top 1 co-cited journal, and the major area of these publications was molecular, biology, and immunology. Nieuwdorp M published the highest number of papers, and Cani PD had the highest co-citations. Keyword analysis showed that the most frequently occurring keywords were "gut microbiota", "insulin-resistance", "obesity", and "inflammation". Trend topics and thematic maps showed that serum metabolome and natural products, such as resveratrol, flavonoids were the research hotspots in this field.

Conclusion

This bibliometric analysis summarised the hotspots, frontiers, pathogenesis, and treatment strategies, providing a clear and comprehensive profile of gut microbiota in IR.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-023-01342-x.

Metabolic syndrome and the urinary microbiome of patients undergoing percutaneous nephrolithotomy

Objective

To identify possible stone-promoting microbes, we compared the profiles of microbes grown from stones of patients with and without metabolic syndrome (MetS). The association between MetS and urinary stone disease is well established, but the exact pathophysiologic relationship remains unknown. Recent evidence suggests urinary tract dysbiosis may lead to increased nephrolithiasis risk.

Methods

At the time of percutaneous nephrolithotomy, bladder urine and stone fragments were collected from patients with and without MetS. Both sample types were subjected to expanded quantitative urine culture (EQUC) and 16 S ribosomal RNA gene sequencing.

Results

Fifty-seven patients included 12 controls (21.1%) and 45 MetS patients (78.9%). Both cohorts were similar with respect to demographics and non-MetS comorbidities. No controls had uric acid stone composition. By EQUC, bacteria were detected more frequently in MetS stones (42.2%) compared to controls (8.3%) (p=0.041). Bacteria also were more abundant in stones of MetS patients compared to controls. To validate our EQUC results, we performed 16 S ribosomal RNA gene sequencing. In 12/16 (75.0%) sequence-positive stones, EQUC reliably isolated at least one species of the sequenced genera. Bacteria were detected in both "infectious" and "non-infectious" stone compositions.

Conclusion

Bacteria are more common and more abundant in MetS stones than control stones. Our findings support a role for bacteria in urinary stone disease for patients with MetS regardless of stone composition.

Epidemiological and biological associations between cardiovascular disease and kidney stone formation: A systematic review and meta-analysis

AIMS

Previous studies find kidney stone formers (KSF) are at greater risk of developing cardiovascular disease (CVD). The underlying mechanisms are poorly understood, and many clinicians are unaware of this connection. We will: DATA SYNTHESIS: Our systematic review is registered with PROSPERO (ID CRD42021251477). We searched epidemiological and biological data. The epidemiological search generated 669 papers, narrowed down to 15. There were 4,259,869 participants (230,720 KSFs). KSF was associated with 25% higher risk of coronary artery disease (CAD) (95% confidence interval (CI): 15, 35%), 17% higher risk of stroke/transient ischemic attacks (TIA) (CI:10, 25%) and 39% higher risk of arterial disease (AD) (CI: 17 65%). Significant heterogeneity was found. Female-identifying KSFs had a higher risk of stroke (ratio = 1.10) and CAD (1.20). The biological search generated 125 papers, narrowed down to 14. Potential underlying mechanisms were extracted and discussed, including intimal/medial vascular calcification, oxidative stress via osteopontin (OPN), cholesterol-induced pathology, and endothelial dysfunction.

CONCLUSIONS

There is a significant association between KSF and CVD, supporting the consideration of KSF as a systemic, calcium-mediated disease. Clinicians will benefit from being aware of this connection.

Uric acid mediated the relationship between obesity and hypertension in children and adolescents: A population‑based cohort study

BACKGROUND AND AIM

Obesity and hyperuricemia (HUA) often coexist and have been widely accepted as risk factors for hypertension, but the role of uric acid (UA) in the relationship between obesity and hypertension remains unknown in children and adolescents.

METHODS AND RESULTS

A total of 7525 subjects aged 6-16 years were from the School-based Cardiovascular and Bone Health Promotion Program (SCVBH) at baseline (2017) and followed up in 2019. Multivariable logistic regression with interaction terms, cross-lagged panel analysis, and causal mediation model were applied to delineate the joint impact of obesity and HUA on hypertension, including the interaction effect, the temporal association, and the mediating effect of UA in the relationship between obesity and hypertension. There were 10.8 % of the participants with normotension at baseline developed hypertension after two years of follow-up. Cross-lagged panel analysis showed that the two-time point association was significant only from baseline BMI to follow-up UA (β1 = 0.302, P < 0.001), but not from baseline UA to follow-up BMI (β2 = 0.002, P = 0.745). Multivariable logistic regression showed that both obesity and HUA increased the risk of hypertension, but no interaction effect between HUA and obesity. The causal mediation analysis found that UA partially mediated the association between BMI and SBP (mediate proportion: 20.3 %, 95 % CI: 17.4-22.9 %) or DBP (mediate proportion: 11.9 %, 95 % CI: 3.9-18.2 %). The results were consistent in the analysis of systolic hypertension rather than diastolic hypertension.

CONCLUSIONS

It is mediating effect that UA played in the progress from obesity to hypertension, particularly systolic hypertension in children and adolescents.

Distinctive biochemistry profiles associated with hyperuricemia between Tibetans and Hans in China

Purpose

We sought to identify distinct risk factors for hyperuricemia in native Tibetan and immigrant Han populations in Tibet, China.

Methods

Three cohorts of male participants aged between 20 and 40 years were enrolled in this study. Biochemical parameters including serum uric acid (UA), fasting plasma glucose, insulin, lactate dehydrogenase (LDH), thyroxin, blood cell count, aminotransferase, and lipid profiles were analyzed. The association of risk factors with UA levels was evaluated using a multivariable line regression model. The effect of UA level on the biochemical parameters between the Hans and Tibetans was evaluated by two-way ANOVA.

Results

The prevalence of hyperuricemia (≥420 μmol/L) was 24.8% (62/250) in the Hans, similar to 23.8% (29/136) in the Tibetans. In the regression analysis, the risk factors that were significantly associated with UA in Hans did not apply to Tibetans. Tibetans had higher fasting insulin (P<0.05) and LDH (P<0.01) levels, in contrast with lower levels of triglycerides (P<0.05), total cholesterol (P<0.01), and low-density lipoprotein-cholesterol (P<0.01) than Hans in normal UA populations. Biochemistry analysis revealed lower albumin levels (P<0.001) and higher levels of all aminotransaminase and especially alkaline phosphatase (P<0.01) in Tibetans than in Hans in both populations. Compared with Hans, Tibetans had lower serum levels of urea, creatinine, and electrolytes in the normal UA population, which were further exacerbated in the high UA population. Tibetans had comparable white blood cell counts as Hans in both normal and high UA populations. In contrast, the red blood cell count and hemoglobin concentration were much lower in Tibetans than in Hans under high UA conditions.

Conclusions

The distinctive biochemistry between Tibetans and Hans may underlie the different etiologies of hyperuricemia in Tibet, China.

Sleep and circadian rhythm disturbance in kidney stone disease: a narrative review

The circadian rhythm generated by circadian clock genes functions as an internal timing system. Since the circadian rhythm controls abundant physiological processes, the circadian rhythm evolved in organisms is salient for adaptation to environmental change. A disturbed circadian rhythm is a trigger for numerous pathological events. Recently, accumulated data have indicated that kidney stone disease (KSD) is related to circadian rhythm disturbance. However, the mechanism between them has not been fully elucidated. In this narrative review, we summarized existing evidence to illustrate the possible association between circadian rhythm disturbance and KSD based on the epidemiological studies and risk factors that are linked to circadian rhythm disturbance and discuss some chronotherapies for KSD. In summary, KSD is associated with systemic disorders. Metabolic syndrome, inflammatory bowel disease, and microbiome dysbiosis are the major risk factors supported by sufficient data to cause KSD in patients with circadian rhythm disturbance, while others including hypertension, vitamin D deficiency, parathyroid gland dysfunction, and renal tubular damage/dysfunction need further investigation. Then, some chronotherapies for KSD were confirmed to be effective, but the molecular mechanism is still unclear.

Association between novel anthropometric indices and prevalence of kidney stones in US adults

BACKGROUND

Our aim is to evaluate the relationship between prevalence of kidney stones (KS) and novel anthropometric indices (AHIs).

METHODS

Participants who participated in the KS questionnaire was extracted from the National Health and Nutrition Examination Survey (NHANES) from 2007 to 2018.A series of covariates were also obtained. The novel AHIs include a body shape index (ABSI) and body roundness index (BRI). Weighted multivariable-adjusted logistic regression was performed to investigate the association of KS with AHIs.

RESULTS

After relative covariates were adjusted, a greater risk of KS for each z score increase in ABSI (OR = 1.13, 95%CI 1.05-1.22), and the risk of KS augmented by 19% for every 1 BRI z score added (OR = 1.19, 95%CI 1.11-1.27). The results from subgroup analysis showed that among adults aged 20-39 (OR = 1.31, 95%CI 1.04-1.65), male (OR = 1.14, 95%CI 1.02-1.28), the risk of KS is higher with the increase of each ABSI z score. Raising each BRI z score in those who were male aged 20-39 and 40-59 resulted in a higher risk of KS (aged 20-39: OR = 1.34, 95%CI 1.06-1.69; aged 40-59: OR = 1.29, 95%CI 1.09-1.53). In female aged 40-59, increasing each BRI z score led to a higher risk of KS (OR = 1.23, 95%CI 1.07-1.41). A linear association of ABSI z score with the risk of KS and a non-linear relationship between BRI z score and the risk of KS were discovered.

CONCLUSION

This study found that the novel AHIs was related to the risk of kidney stones, and can be used as important indicators to evaluate the risk of KS.

Relationship between the weight-adjusted-waist index and kidney stone: a population-based study

BACKGROUND

At present, a growing number of studies have shown a positive association between obesity and kidney stone, while traditional anthropometric measures, such as body mass index (BMI) and Waist circumference (WC), have limited ability to assess the risk of kidney stone. Therefore, this study aimed to investigate the association between the weight-adjusted-waist index (WWI) and the risk of kidney stone.

METHOD

Data from the National Health and Nutrition Examination Survey (NHANES) between 2009 and 2016 were used. A total of 17,292 participants from NHANES were included in the study. Multivariate logistic regression and restricted cubic splines (RCS) were used to investigate the relationship between WWI and kidney stone. Interaction analysis was performed for subgroups to verify the results. Meanwhile, the receiver operating characteristic curve (ROC) was used to analyze the efficacy of different anthropometric indices in predicting the risk of kidney stone.

RESULTS

After adjusting for potential confounding factors, we found a positive and independent association between kidney stone and WWI. After adjusting for all covariates, a one-unit increase in WWI was associated with a 36% increase in the risk of kidney stones. Dose-response curve analysis showed that WWI was non-linear correlated with the prevalence of kidney stone. In ROC analysis, WWI showed better discrimination for kidney stone (area under the curve: 0.612; 95% CI: 0.599-0.626; optimal cutoff value: 11.063) compared with other indices.

CONCLUSION

In this study, increased WWI was strongly associated with the risk of kidney stone.

The role of SGLT2i in attenuating residual cardiovascular risk through blood pressure-lowering: mechanistic insights and perspectives

Sodium glucose cotransporter 2 inhibitors (SGLT2) have been increasingly pursued as a promising target for addressing residual cardiovascular risk. Prior trials demonstrated that SGLT2i not only promotes glucose-lowering, but also improves endothelial dysfunction, adiposity, fluid overload, and insulin sensitivity thus contributing to hemodynamic changes implicated in its cardiorenal benefits. The mechanisms in the effect of SGLT2i on blood pressure and their potential role in preventing cardiovascular events are hereby revised.

Insulin resistance surrogate markers and risk of hyperuricemia among patients with and without coronary artery disease: a cross-sectional study

Background

Although emerging evidence emphasizes the associations between both insulin resistance and hyperuricemia with coronary artery disease (CAD) risk, no definite relationship has yet been established. In this respect, time-efficient and affordable methods to estimate insulin resistance (IR) status, and to predict risk of hyperuricemia, are needed. Thus, the goal of this investigation was to examine the associations between IR, as assessed by novel surrogate markers [triglyceride-glucose (TyG) and TyG-body mass index (TyG-BMI)], and risk of hyperuricemia in patients with and without diagnosed CAD.

Methods

This cross-sectional study used data from the medical records of 1,170 patients who were referred to the cardiology outpatient clinic. Medical records, anthropometrics, and serum analytes were determined at the initial visit. Hyperuricemia was defined as serum uric acid ≥ 5.6 mg/dL. IR was estimated through surrogate markers (TyG and TyG-BMI). Multiple regression analysis was performed to assess the relationship between these indices and odds of hyperuricemia among patients with and without CAD.

Results

Overall, 814 angiographically-confirmed CAD cases (mean age (SD) = 52 (8)yrs) were compared with 356 patients without CAD (mean age (SD) = 48 (8)yr). There were positive associations between TyG and TyG-BMI indices and odds of hyperuricemia in CAD patients after controlling for confounders (adjusted odds ratio (aOR) = 1.60; 95%CI: 1.02-2.51; p-value = 0.036; and aOR = 1.83; 95%CI: 1.24-2.70; p-value = 0.002, third tertiles for TYG and TYG-BMI, respectively).

Conclusion

The present findings suggest that higher levels of the IR surrogate markers, TyG and TyG-BMI, are associated with higher odds of hyperuricemia in patients with CAD. However, given the cross-sectional design of this study, the sensitivity and specificity of these novel markers could not be determined for confirming the diagnosis of IR and hyperuricemia, further studies are needed to determine such outcomes and to confirm the current findings.

Hyperuricemia and gout increased the risk of long-term mortality in patients with heart failure: insights from the National Health and Nutrition Examination Survey

BACKGROUND

The prevalence of hyperuricemia, gout, and heart failure (HF) is on the rise, and these conditions often share similar risk factors. The present study aimed to evaluate the relationship among hyperuricemia, gout, HF, and all-cause mortality.

METHODS

The data on nonpregnant participants aged ≥ 20 years with or without hyperuricemia, gout, and HF from the National Health and Nutrition Examination Survey 2001-2018 and 2007-2018 were included in this study. The binary logistic regression, Kaplan-Meier curve, Cox proportional-hazards model, and restricted cubic spline analysis were employed to evaluate the relationship among hyperuricemia, gout, HF, and all-cause mortality.

RESULTS

Of 204,179,060 and 223,702,171 weighted eligible participants, 40,044,228 (19.6%) and 9,158,600 (4.1%) had hyperuricemia and gout, respectively. Older age, diabetes, stroke, and coronary artery disease were the risk factors for HF among patients with hyperuricemia and gout. The median survival time was 7.00 years and 6.25 years and the 5-year survival rate was 59.9% and 55.9% for patients with HF and hyperuricemia and those with HF and gout, respectively. Patients with hyperuricemia or gout were 2.46 and 2.35 times more likely to have HF and 1.37 and 1.45 times more likely to experience all-cause mortality compared with those who did not exhibit these conditions. The restricted cubic spline showed a nonlinear correlation between uric acid levels and HF and a J-shaped correlation between uric acid levels and all-cause mortality.

CONCLUSIONS

Ambulatory patients with hyperuricemia or gout were more likely to have HF compared with those without hyperuricemia or gout. Patients with HF with hyperuricemia or gout were more likely to experience all-cause mortality in the long-term follow-up.

Association between metabolically healthy obesity and kidney stones: results from the 2011-2018 National Health and Nutrition Examination Survey

Introduction

The risk of kidney stones in metabolically healthy obesity (MHO) individuals is largely unexplored. This study using percent body fat (%BF) to categorize obesity, to investigate the association between MHO as well as other metabolic syndrome-obesity combined phenotypes and kidney stones in a national representative population.

Materials and methods

This cross-sectional study included 4,287 participants in the National Health and Nutrition Examination Survey from 2011 to 2018. Metabolically healthy status was defined as not having any component of metabolic syndrome or insulin resistance. Obesity was identified by %BF, which was measured and assessed by dual-energy x-ray absorptiometry (DXA) scan. Participants were cross-classified by metabolic health and obesity status. The outcome was self-report kidney stones. Multivariable logistic regression model was used to examine the association between MHO and kidney stones.

Results

A total of 358 participants had kidney stones [weighted prevalence (SE): 8.61% (0.56%)]. The weighted prevalence (SE) of kidney stones in MHN, MHOW, and MHO groups was 3.13% (1.10%), 4.97% (1.36%), and 8.55% (2.09%), respectively. After adjusting for age, sex, race and ethnicity, education level, smoking status, alcohol consumption, physical activity, daily water intake, CKD stage 3-5, and hyperuricemia, MHO individuals (OR: 2.90, 95% CI: 1.18, 7.0) had a significantly higher risk of kidney stones than those with metabolically healthy normal weight. In metabolically healthy participants, a 5% increment in %BF was associated with a significantly higher risk of kidney stones (OR: 1.60, 95% CI: 1.20, 2.14). Furthermore, a nonlinear dose-response relationship between %BF and the kidney stones was observed in metabolically healthy participants (P for non-linearity = 0.046).

Conclusion

Using %BF to define obesity, MHO phenotype was significantly associated with higher risks of kidney stones, suggesting that obesity can independently contribute to kidney stones in the absence of metabolic abnormalities and insulin resistance. Regarding kidney stones prevention, MHO individuals might still benefit from lifestyle interventions aimed at healthy body composition maintenance.

Valproate-Induced Metabolic Syndrome

Valproic acid (VPA) and its salts (sodium calcium magnesium and orotic) are psychotropic drugs that are widely used in neurology and psychiatry. The long-term use of VPA increases the risk of developing adverse drug reactions (ADRs), among which metabolic syndrome (MetS) plays a special role. MetS belongs to a cluster of metabolic conditions such as abdominal obesity, high blood pressure, high blood glucose, high serum triglycerides, and low serum high-density lipoprotein. Valproate-induced MetS (VPA-MetS) is a common ADR that needs an updated multidisciplinary approach to its prevention and diagnosis. In this review, we consider the results of studies of blood (serum and plasma) and the urinary biomarkers of VPA-MetS. These metabolic biomarkers may provide the key to the development of a new multidisciplinary personalized strategy for the prevention and diagnosis of VPA-MetS in patients with neurological diseases, psychiatric disorders, and addiction diseases.

Metabolic changes in kidney stone disease

Kidney stone disease (KSD) is one of the earliest medical diseases known, but the mechanism of its formation and metabolic changes remain unclear. The formation of kidney stones is a extensive and complicated process, which is regulated by metabolic changes in various substances. In this manuscript, we summarized the progress of research on metabolic changes in kidney stone disease and discuss the valuable role of some new potential targets. We reviewed the influence of metabolism of some common substances on stone formation, such as the regulation of oxalate, the release of reactive oxygen species (ROS), macrophage polarization, the levels of hormones, and the alternation of other substances. New insights into changes in substance metabolism changes in kidney stone disease, as well as emerging research techniques, will provide new directions in the treatment of stones. Reviewing the great progress that has been made in this field will help to improve the understanding by urologists, nephrologists, and health care providers of the metabolic changes in kidney stone disease, and contribute to explore new metabolic targets for clinical therapy.

Causal effects of modifiable risk factors on kidney stones: a bidirectional mendelian randomization study

BACKGROUND

Increasing epidemiological studies demonstrated that modifiable risk factors affected the risk of kidney stones. We aimed to systemically assess these causal associations using a bidirectional Mendelian randomization study.

METHODS

We obtained instrumental variables related to each exposure at the genome-wide significant threshold (P < 5 × 10^-8). Summary level data for outcomes from the FinnGen consortium and UK Biobank were utilized in the discovery and replication stage. The Inverse-variance weighted (IVW) method was used as the primary analysis, with additional sensitivity analyses and fix-effect meta-analysis to verify the robustness of IVW results.

RESULTS

Among 46 risk factors, five were significantly associated with nephrolithiasis risk in the FinnGen consortium, UK Biobank, and meta-analyses collectively. The odds ratios (ORs) (95% confidence intervals [95%CIs]) of kidney stones were 1.21 (1.13, 1.29) per standard deviation (SD) increase in serum calcium, 1.55 (1.01, 2.36) per SD increase in serum 25(OH)D, 1.14 (1.00, 1.29) per SD increase in total triglycerides, 2.38 (1.34, 4.22) per SD increase in fasting insulin, and 0.28 (0.23, 0.35) per unit increase in log OR of urine pH. In addition, genetically predicted serum phosphorus, urinary sodium, tea consumption, and income affected the risk of kidney stones (false discovery rate [FDR] P < 0.05) based on the outcome data from the FinnGen consortium, and the significant associations of education and waist-to-hip ratio with nephrolithiasis risks were found after FDR correction (FDR P < 0.05) based on the outcome data from UK Biobank.

CONCLUSIONS

Our findings comprehensively provide modifiable risk factors for the prevention of nephrolithiasis. Genome-wide association studies with larger sample sizes are needed to verify these causal associations in the future further.

Causal association of genetically predicted urinary sodium-potassium ratio and upper urinary calculi

The causality between the urinary sodium-potassium ratio and upper urinary calculi has not been clarified and easily affected by confounders. We performed two-sample and multivariable Mendelian randomization (MR) analysis to evaluate the potential causal role of the urinary sodium-potassium ratio in upper urinary calculi. Data of the urinary sodium-potassium ratio (N = 326,938), upper urinary calculi (N = 337,199), and confounding factors including BMI (N = 336,107), ever-smoke (N = 461,066), hypertension (N = 218,754), diabetes (N = 218,792), and alcohol intake frequency (N = 462,346) were obtained from the IEU OpenGWAS Project database. The inverse-variance weighted (IVW), weighted median, and MR-Egger methods were used to estimate MR effects. The MR-Egger intercept test, Cochran's Q test, MR-PRESSO, leave-one-out method, and funnel plot were used for sensitivity analysis. A causal relationship was found between the urinary sodium-potassium ratio and upper urinary calculi (OR = 1.008, 95% CI = 1.002-1.013, P = 0.011). FinnGen data supported this conclusion (OR = 2.864, 95% CI = 1.235-6.641, P = 0.014). The multivariable Mendelian randomization analysis result showed that after adjusting for the effects of five confounders, the urinary sodium-potassium ratio was still positively correlated with upper urinary calculi (OR = 1.005, 95% CI = 1.001-1.009, P = 0.012). This study demonstrated a positive causal association between the urinary sodium-potassium ratio and upper urinary calculi using MR analysis. Timely identification of changes in urine composition and dietary regulation of sodium and potassium intake could greatly reduce the incidence of future urinary calculi.

Increased circulating uric acid aggravates heart failure via impaired fatty acid metabolism

BACKGROUND

Increased circulating uric acid (UA) concentration may disrupt cardiac function in heart failure patients, but the specific mechanism remains unclear. Here, we postulate that hyperuremia induces sterol regulatory element binding protein 1 (SREBP1), which in turn activate hepatic fatty acid biosynthesis response, leading to cardiac dysfunction.

METHODS AND RESULTS

Increased circulating uric acid was observed in heart failure patients and inversely correlated to cardiac function. Besides, uric acid correlated to circulating lipids profile based on metabolomics in heart failure patients. Using cultured human hepatoellular carcinomas (HepG2) and Tg(myl7:egfp) zebrafish, we demonstrated that UA regulated fatty acid synthase (FASN) via SREBP1 signaling pathway, leading to FFA accumulation and impaired energy metabolism, which could be rescued via SREBP1 knockdown. In ISO treated zebrafish, UA aggravated heart failure via increased cardiovascular cavity size, decreased heart beats, pericardial edema and long-stretched heart deformation.

CONCLUSIONS

Our findings suggest that UA-SREBP1-FASN signaling exacerbates cardiac dysfunction during FFA accumulation. Identification of this mechanism may help in treatment and prevention of heart failure.

Determinants of renal papillary appearance in kidney stone formers: An in-depth examination

OBJECTIVES

The aim of this study is to investi-gate the association between the urinary metabolic milieu and kidney stone recurrence with a validated papillary evaluation score (PPLA).

MATERIALS AND METHODS

We prospectively enrolled 30 stone for-mers who underwent retrograde intrarenal surgery procedures. Visual inspection of the accessible renal papillae was performed to calculate PPLA score, based on the characterization of ductal plugging, surface pitting, loss of papillary contour and Randall's plaque extension. Stone compositions, 24h urine collections and kidney stone events during follow-up were collected. Relative supersaturation ratios (RSS) for calcium oxalate (CaOx), brushite and uric acid were calculated using EQUIL-2. PPLA score > 3 was defined as high.

RESULTS

Median follow-up period was 11 months (5, 34). PPLA score was inversely correlated with BMI (OR 0.59, 95% CI 0.38, 0.91, p = 0.018), type 2 diabetes (OR 0.04, 95% CI 0.003, 0.58, p = 0.018) and history of recurrent kidney stones (OR 0.17, 95%CI 0.04, 0.75, p = 0.019). The associations between PPLA score, diabetes and BMI were not confirmed after excluding patients with uric acid stones. Higher PPLA score was associated with lower odds of new kidney stone events during follow-up (OR 0.15, 95% CI 0.02, 1.00, p = 0.05). No other significant correla-tions were found.

CONCLUSIONS

Our results confirm the lack of efficacy of PPLA score in phenotyping patients affected by kidney stone disease or in predicting the risk of stone recurrence. Larger, long-term studies need to be performed to clarify the role of PPLA on the risk of stone recurrence.

High-Fructose Diet-Induced Hyperuricemia Accompanying Metabolic Syndrome-Mechanisms and Dietary Therapy Proposals

Fructose is often used as a food ingredient due to its low production costs and sweetening power. In recent years, it has been noticed that people on a Western diet high in fructose have high levels of uric acid in their blood. It was recognized that the specific metabolism of fructose in the body might cause increased production of uric acid, which then may affect the intensification of lipogenesis and the development of metabolic syndrome (MetS), insulin resistance, gout, cardiovascular diseases, leptin resistance, or non-alcoholic fatty liver disease. So far, to treat hyperuricemia, it has been recommended to use a low-purine diet characterized by limiting protein-containing products. However, this recommendation often leads to an increased intake of carbohydrate-rich foods that may contain fructose. Increased fructose consumption may enhance the secretion of uric acid again and, consequently, does not have therapeutic effects. Therefore, instead of a low-purine diet, using healthy diets, such as DASH or the Mediterranean diet, which can benefit metabolic parameters, could be a better proposal. This article provides an overview of this approach, focusing on MetS and hyperuricemia among high-fructose dieters.

Epidemiology of Kidney Stones

In the past two decades, major breakthroughs that improve our understanding of the pathophysiology and therapy of kidney stones (KS) have been lacking. The disease continues to be challenging for patients, physicians, and healthcare systems alike. In this context, epidemiological studies are striving to elucidate the worldwide changes in the patterns and the burden of the disease and identify modifiable risk factors that contribute to the development of kidney stones. Our expanding knowledge of the epidemiology of kidney stones is of paramount importance and largely upgrades the modern management of the disease. In this paper, we review the variables affecting prevalence and incidence, including age, gender, race, ethnicity, occupation, climate, geography, systemic diseases, diabetes, vascular disease, chronic kidney disease, and dietary risk factors relevant to kidney stones.

Kidney stones among Iranian adults: Prevalence and socioeconomic inequality assessment in a cohort-based cross-sectional study

Background and Aims

Kidney stone disease is a crystal concretion formed usually within the kidneys. The worldwide prevalence of kidney stones could be affected by numerous differences in socioeconomic, and environmental factors. The purpose of this study is to investigate kidney stones among Iranian adults aged between 35 and 70 years and the prevalence and evaluation of socioeconomic inequalities.

Methods

In this, a cohort-based cross-sectional study was carried out among 20,427 participants of ArNCDs aged 35 and 70 years old. Kidney stone was defined as a dependent (and binary) variable while demographic and socioeconomic factors were considered independent variables. Multivariable logistic regression was used to identify the key socioeconomic factors affecting kidney stone prevalence in Ardabil.

Results

The overall prevalence of kidney stones was 17.6 (95% confidence interval [CI]: 16.1-19.2) out of which 21.53% and 14.36% pertained to men and women and 14.18% and 23.17% pertained to the poorest and richest groups, respectively. There was a significant difference in the prevalence of kidney stones between men and women in terms of age, marital status, education level, chronic disease, body mass index, and socioeconomic status (<0.001). The prevalence of kidney stones had a positive correlation with age (1.7, 95% [CI]: 1.42-2.04) and socioeconomic status (1.5, 95% [CI]: 1.34-1.69), where the odds of kidney stones increased significantly by increasing age and socioeconomic status. Moreover, the kidney stone concentration index showed a pro-rich distribution wherein it was more common among wealthy people (higher socioeconomic status) 0.062 (95% [CI]: 0.051-0.072).

Conclusion

The results of this study showed that there is significant inequality in the prevalence of kidney stones, where it was more common among the richest people. In addition, being men and old age are significantly related to kidney stones, so policymakers and physicians should consider these factors.

Nephrolithiasis: A Red Flag for Cardiovascular Risk

Epidemiological evidence shows that nephrolithiasis is associated with cardiovascular (CV) morbidities. The association between nephrolithiasis and CV disease is not surprising because both diseases share conditions that facilitate their development. Metabolic conditions, encompassed in the definition of metabolic syndrome (MS), and habits that promote nephrolithiasis by altering urine composition also promote clinical manifestations of CV disease. By inducing oxidative stress, these conditions cause endothelial dysfunction and increased arterial stiffness, which are both well-known predictors of CV disease. Furthermore, the subtle systemic metabolic acidosis observed in stone formers with CV disease may have a pathogenic role by increasing bone turnover and leading to reduced mineral content and osteoporosis/osteopenia. Heart valves and/or coronary artery and aortic calcifications are frequently associated with reduced mineral density. This is known as the 'calcification paradox' in osteoporosis and has also been observed in subjects with calcium nephrolithiasis. Evidence supports the hypothesis that osteoporosis/osteopenia is an independent risk factor for the development of CV calcifications. In the long term, episodes of renal stones may occur from the onset of metabolic derangements/MS to arterial stiffness/atherosclerosis and CV morbidities. These episodes should be considered a warning sign of an ongoing and silent atherosclerotic process. The evaluation of cardiometabolic risk factors and MS components should be routine in the assessment of renal stone formers. This would allow for treatment and prevention of the development of CV complications, which are much more severe for the patient and for public health.

Modification effect of changes in cardiometabolic traits in association between kidney stones and cardiovascular events

Backgrounds

Whether longitudinal changes in metabolic status influence the effect of kidney stones on cardiovascular disease (CVD) remains unclarified. We investigated the modification effect of status changes in metabolic syndrome (MetS) in the association of kidney stones with risk of incident CVD events.

Methods

We performed a prospective association and interaction study in a nationwide cohort including 129,172 participants aged ≥ 40 years without CVDs at baseline and followed up for an average of 3.8 years. Kidney stones information was collected by using a questionnaire and validated by medical records. The repeated biochemical measurements were performed to ascertain the metabolic status at both baseline and follow-up.

Results

4,017 incident total CVDs, 1,413 coronary heart diseases (CHDs) and 2,682 strokes were documented and ascertained during follow-up. Kidney stones presence was significantly associated with 44%, 70% and 31% higher risk of CVDs, CHDs and stroke, respectively. The stratified analysis showed significant associations were found in the incident and sustained MetS patients, while no significant associations were found in the non-MetS at both baseline and follow-up subjects or the MetS remission ones, especially in women. For the change status of each single component of the MetS, though the trends were not always the same, the associations with CVD were consistently significant in those with sustained metabolic disorders, except for the sustained high blood glucose group, while the associations were consistently significant in those with incident metabolic disorders except for the incident blood pressure group. We also found a significant association of kidney stone and CVD or CHD risk in the remain normal glucose or triglycerides groups; while the associations were consistently significant in those with incident metabolic disorders except for the incident blood pressure group. We also found a significant association of kidney stone and CVD or CHD risk in the remain normal glucose or triglycerides groups.

Conclusions

A history of kidney stones in women with newly developed MetS or long-standing MetS associated with increased risk of CVD. The mechanisms link kidney stones and CVD risk in the metabolic and non-metabolic pathways were warranted for further studies.

Association Between Healthy Eating Index-2015 and Kidney Stones in American Adults: A Cross-Sectional Analysis of NHANES 2007-2018

Purpose

To explore the association between Healthy Eating Index (HEI)-2015 and kidney stones in an American adult population.

Materials and Methods

National Health and Nutrition Examination Survey (NHANES) datasets from 2007 to 2018 were used. Participants aged ≥ 20 years who reported kidney stone history and dietary recall were included. Weighted proportions, multivariable analysis and spline smoothing were used to evaluate the associations between HEI-2015 and nephrolithiasis by adjusting gender, age, race, poverty income ratio, body mass index, education level, marital status, smoking, alcohol intake, energy level, vigorous activity, moderate activity, and some comorbidities.

Results

Totally 30 368 American adults were included, with weighted mean age [standard deviation (SD)] of 47.69 (16.85) years. The overall mean HEI-2015 score (SD) was 50.82 (13.80). In the fully-adjusted multivariable model, HEI-2015 was negatively correlated with urolithiasis [odds ratio (OR) = 0.991; 95% confidence interval (CI) 0.988 to 0.994]. Compared with the first quartile of HEI-2015, the population in the fourth quartile of HEI-2015 had a lower prevalence of kidney stones (OR = 0.716; 95% CI 0.635 to 0.807). The association was modified by education and vigorous activity.

Conclusions

HEI-2015 is inversely associated with the prevalence of kidney stones, which means better diet quality is associated with a lower risk of nephrolithiasis.

Insulin Resistance and Urolithiasis as a Challenge for a Dietitian

Many obesity and diet-related diseases have been observed in recent years. Insulin resistance (IR), a state of tissue resistance to insulin due to its impaired function, is a common coexisting condition. The most important predisposing factors are excessive visceral fat and chronic low-grade inflammatory response. However, IR’s pathogenesis is not fully understood. Hence, the diagnosis of IR should be carried out carefully because many different diagnostic paths do not always give equivalent results. An additional disease that is often associated with IR is urolithiasis. The common feature of these two conditions is metabolic acidosis and mild inflammation. A patient diagnosed with IR and urolithiasis is a big challenge for a dietitian. It is necessary to check a thorough dietary history, make an appropriate anthropometric measurement, plan a full-fledged diet, and carry out the correct nutritional treatment. It is also essential to conduct proper laboratory diagnostics to plan nutritional treatment, which is often a big challenge for dietitians. The diet’s basic assumptions are based on the appropriate selection of carbohydrates, healthy fats, and wholesome protein sources. It is also essential to properly compose meals, prepare them, and plan physical activities tailored to the abilities. The study aims to summarise the necessary information on IR with concomitant urolithiasis, which may be helpful in dietary practice.

Effects of metabolic syndrome on renal stone progression

PURPOSE

Studies on howmetabolic syndrome affects renal stone progression in untreated asymptomatic patients are lacking. Therefore, we investigated the effect of metabolic syndrome on changes in renal stone size.

MATERIALS AND METHODS

We retrospectively analyzed 820 patients with renal stones incidentally detected on CT during regular health examinations and who underwent follow-up CT evaluations for > 1 year. The patients were divided into two groups according to the presence of metabolic syndrome. Changes in stone size during the follow-up were assessed, and differences were compared according to various factors. Predictors of stone size change on CT were assessed using linear regression analysis.

RESULTS

Overall, 820 asymptomatic patients without a history of stone treatments and with a mean follow-up of 52.4 months were included. Of these, 104 (12.7%) had metabolic syndrome and 335 (40.9%) showed stone size increase during the follow-up. The stone size at diagnosis was not significantly different between patients with and without metabolic syndrome (225.3 ± 332.6 vs. 183.9 ± 310.2 mm³, p = 0.159); however, a significant difference was observed in the change in stone size at follow-up (148.5 ± 352.0 vs. 81.5 ± 222.4 mm³, p = 0.001). Multivariable analysis showed that age (β = - 0.11; - 5.92 to -0.69; p = 0.013), fasting glucose level ≥ 100 mg/dl (β = 0.11; 9.78-99.73; p = 0.017), and metabolic syndrome (β = 0.10; 9.78-99.73; p = 0.017) were factors predictive of stone size changes.

CONCLUSION

Metabolic syndrome, fasting glucose level ≥ 100 mg/dl and young age are positively related to renal stone size changes. Therefore, periodic follow-up and metabolic syndrome management are required in asymptomatic patients with renal stones, especially in young age.

Why is diagnosis, investigation and improved management of kidney stone disease important? Non-pharmacological and pharmacological treatments for nephrolithiasis

INTRODUCTION

Progress in the medical treatment and management of nephrolithiasis has been limited to date and continues to depend on urinary metabolic screening to assess excretion of the main stone constituents, factors determining stone solubility and precipitation, and on dietary and lifestyle recommendations.

AREAS COVERED

In this review, we try to highlight some of the broader aspects of kidney stone disease in relation to recent epidemiological and pathophysiological findings, and emerging new treatments. Specifically, this review will cover recent evidence on the association between metabolic risk factors and kidney stone disease, dietary risk factors and dietary interventions to prevent kidney stones, and how genomics, metabolomics and proteomics may improve diagnosis and treatment of this troublesome, if rarely fatal, condition. PubMed was used to identify the most suitable references according to our search strategy; only full manuscripts were included.

EXPERT OPINION

What is emerging is that kidney stone disease is not an isolated disorder, but is systemic in nature with links to important and common co-morbidities such as diabetes, hypertension, cardiovascular disease, and chronic kidney disease. These associations support the need to take nephrolithiasis seriously as a medical condition and to adopt a more holistic approach to its investigation and treatment.

The impacts of metabolic syndrome on the risk of severe urolithiasis

Metabolic syndrome (MetS) is significantly correlated with urolithiasis. However, few studies have evaluated the severity of urolithiasis. This study aimed to investigate the relationship of MetS with severe urolithiasis disease (SUD). The data of 910 patients with urolithiasis in the Department of Urology, Second Hospital of Tianjin Medical University from June 2020 to May 2021 were retrospectively collected. The patients were divided into two groups according to the severity of urolithiasis, and the relationships of MetS and its components with SUD were evaluated. The results showed 605 SUD and 272 Mets patients. Multiple regression analysis showed that middle age, male gender, and MetS increased the risk of SUD, whereas serum magnesium decreased it (P < 0.05). Further analysis revealed that the odds ratio (OR) of SUD increased with MetS grade (0-4) (1.029-2.117). Grade 4 patients had a 2.1-fold higher risk of SUD than grade 0 patients (OR 2.117; 95% CI 1.053-4.256; P = 0.035); hypertension and dyslipidemia were most strongly associated with SUD among the four MetS features (P < 0.05). Additionally, calcium oxalate was the most predominant stone component (78.7%) in the SUD(+) group, which also had stones with higher uric acid and lower calcium oxalate dihydrate levels than those of the SUD(-) group (P < 0.05). Our study concluded that SUD is more common in middle-aged men, MetS is an independent risk factor for SUD. The more severe the MetS, the higher the risk of SUD, in which hypertension and dyslipidemia play major roles.

Association between liver-type fatty acid-binding protein and hyperuricemia before and after laparoscopic sleeve gastrectomy

BACKGROUND

Liver-type fatty acid-binding protein (FABP1) contributes to metabolic disorders. However, the relationship between FABP1 and hyperuricemia remains unknown. We aimed to evaluate the correlation between serum FABP1 and hyperuricemia in patients with obesity before and after laparoscopic sleeve gastrectomy (LSG).

METHODS

We enrolled 105 patients (47 men and 58 women) with obesity who underwent LSG. They were divided into two groups: normal levels of uric acid (UA) (NUA, n = 44) and high levels of UA (HUA, n = 61) with matching sexes. FABP1 levels and other biochemical parameters were measured at baseline and 3, 6, and 12 months after LSG.

RESULTS

Serum FABP1 levels were significantly higher in the HUA group than in the NUA group (34.76 ± 22.69 ng/mL vs. 25.21 ± 21.68 ng/mL, P=0.024). FABP1 was positively correlated with UA (r=0.390, P=0.002) in the HUA group. The correlation still existed after adjusting for confounding factors. Preoperative FABP1 levels were risk factors for hyperuricemia at baseline. UA and FABP1 levels decreased at 3, 6, and 12 months postoperatively. FABP1 showed a more significant decrease in the HUA group than in the NUA group at 12 months (27.06 ± 10.98 ng/mL vs. 9.54 ± 6.52 ng/mL, P=0.003). Additionally, the change in FABP1 levels positively correlated with changes in UA levels in the HUA group 12 months postoperatively (r=0.512, P=0.011).

CONCLUSIONS

FABP1 was positively associated with UA and may be a risk factor for hyperuricemia in obesity. FABP1 levels were higher but decreased more after LSG in obese patients with hyperuricemia than in those without hyperuricemia.

Is the METS-IR Index a Potential New Biomarker for Kidney Stone Development?

OBJECTIVE

The purpose of this study was to examine whether the METS-IR index is associated with kidney stones in American adults.

METHOD

Participants from the National Health and Nutrition Examination Survey (NHANES) database from 2007-2018 were selected for logistic regression analysis, subgroup analyses, and the calculation of dose-response curves to assess the association between the METS-IR index and the incidence of kidney stones.

RESULT

This study enrolled 30,612 adults aged >20 years, 2901 of whom self-reported having had kidney stones in the past. And, after controlling for potential confounders, each unit increase in the METS-IR index was linked with a 1.23 percent rise in kidney stone incidence (OR= 1.0123, 95% CI: 1.0092 - 1.0155), with stratified analysis indicating that this was true in all subgroups. Between all groups, an elevated METS-IR index was related to kidney stone formation, and the dose-response curve revealed a positive non-linear connection between METS-IR index and kidney stone risk, with a threshold effect analysis revealing an inflection point value of 50.8314.

CONCLUSION

Higher METS-IR index is associated with the occurrence of kidney stones,and while no causative association can be shown, this is cause for concern.

Triglyceride-Glucose Index Correlate With Telomere Length in Healthy Adults From the National Health and Nutrition Examination Survey

AIM

The present investigation was designed to test the association between leukocyte telomere length (LTL) and two simple markers of insulin resistance, that is, homeostatic model assessment of insulin resistance (HOMA-IR) and triglyceride-glucose (TyG) index in U.S. adults without metabolic diseases.

METHODS

A total of 6489 U.S. adults without diabetes from NHANES 1999-2002 were analyzed. TyG index was calculated as ln [fasting triglycerides (mg/dL) × fasting glucose (mg/dL)/2]. HOMA-Index was calculated as fasting plasma glucose (mmol/L) × fasting serum insulin (mU/mL)/22.5. LTL was obtained using the quantitative polymerase chain reaction method. Multivariate linear regression analysis was assessed to evaluate the association of TyG index HOMA-IR with LTL. We further conducted a generalized additive model (GAM) and a fitted smoothing curve with penalized spline method.

RESULTS

It was found that the mean LTL was 5796.1 bp in the measured healthy adults. Overall, TyG index was significantly associated with LTL, while HOMA-IR was not. Compared with participants in tertile 1 of the TyG index, the β (95% CI) for those in the second (8.27 to 8.77) and third (≥ 8.77) were -4.31 (95% CI: -48.12~39.49) and -95.98 (95% CI: -145.08~-46.89), respectively. Subjects with TyG index ≥ 8.77 had statistically significant shorter LTL (β = -93.33, 95%CI: -134.33~-52.32), compared with TyG index < 8.77. We further explored a dose-response relation between TyG index by a decile approach [≤ 7.81 (reference), 7.81-8.04, 8.04-8.21, 8.21-8.37, 8.37-8.52, 8.52-8.68, 8.68-8.83, 8.83-9.03, 9.03-9.33, and >9.33] and LTL. Five subgroups (TyG index 7.81-8.04, 8.04-8.21, 8.21-8.37, 8.37-8.52, and 8.52-8.68) did not show significant effect on LTL; while there was a significantly shorter LTL for participants with the TyG index > 8.68, supporting a threshold effect of TyG index on LTL.

CONCLUSIONS

The results suggested that higher TyG index (> 8.68) was closely related to shorter LTL and the TyG index was better associated with LTL than HOMA-IR.

Fructose-Rich Diet Is a Risk Factor for Metabolic Syndrome, Proximal Tubule Injury and Urolithiasis in Rats

Excessive consumption of fructose (FR) leads to obesity, metabolic syndrome (MS) and insulin resistance, which are known risk factors for kidney stones. The epidemiological study has suggested the association between fructose consumption and urolithiasis, but the precise mechanism is still not well understood. Male Wistar rats were assigned for 8 weeks to three groups with different FR content in diet: RD (n = 5)-regular diet with a FR < 3%; F10 (n = 6)-regular diet with an addition of 10% Fr in drinking water; F60 (n = 5)-60% FR as a solid food. Serum concentration of FR, creatinine (Cr), insulin (Ins), triglycerides (Tg), homocysteine (HCS), uric acid (UA), calcium (Ca), phosphate (Pi), magnesium (Mg) and sodium (Na) were measured. Based on 24 h urine collection the following tests were performed: urine pH, proteinuria (PCR), excretion of N-Acetyl-(D)-Glucosaminidase (NAG), monocyte chemoattractant protein (MCP-1), uric acid (uUAEx), phosphate (uPiEx), calcium (uCaEx), magnesium (uMgEx) and sodium (uNaEx). The creatinine clearance (CrCl) was calculated. Calcium deposits in kidney sections were examined using hematoxylin and eosin (HE) and von Kossa stains. The rats on F10 and F60, as compared to the RD diet, showed a tendency for lower CrCl, higher HCS level and some features of MS as higher Ins and TG levels. Interestingly, F10 (fluid) versus F60 (solid) diet led to higher serum Ins levels. F10 and F60 versus RD demonstrated higher urinary excretion of MCP-1 and NAG which were suggestive for inflammatory injury of the proximal tubule. F10 and F60 as compared to RD showed significantly lower uUAEx, although there were no differences in clearance and fractional excretion of UA. F60 versus RD induced severe phosphaturia (>30×) and natriuria (4×) and mild calciuria. F10 versus RD induced calciuria (3×), phosphaturia (2×) and mild natriuria. Calcium phosphate stones within the tubules and interstitium were found only in rats on FR diet, respectively, in two rats from the F10 group and another two in the F60 group. The rats which developed stones were characterized by significantly higher serum insulin concentration and urinary excretion of calcium and magnesium. A fructose-rich diet may promote development of calcium stones due to proximal tubule injury and metabolic syndrome.

Calcium and Vitamin D Supplementation and Their Association with Kidney Stone Disease: A Narrative Review

Kidney stone disease is a multifactorial condition influenced by both genetic predisposition and environmental factors such as lifestyle and dietary habits. Although different monogenic polymorphisms have been proposed as playing a causal role for calcium nephrolithiasis, the prevalence of these mutations in the general population and their complete pathogenetic pathway is yet to be determined. General dietary advice for kidney stone formers includes elevated fluid intake, dietary restriction of sodium and animal proteins, avoidance of a low calcium diet, maintenance of a normal body mass index, and elevated intake of vegetables and fibers. Thus, balanced calcium consumption protects against the risk for kidney stones by reducing intestinal oxalate availability and its urinary excretion. However, calcium supplementation given between meals might increase urinary calcium excretion without the beneficial effect on oxalate. In kidney stone formers, circulating active vitamin D has been found to be increased, whereas higher plasma 25-hydroxycholecalciferol seems to be present only in hypercalciuric patients. The association between nutritional vitamin D supplements and the risk for stone formation is currently not completely understood. However, taken together, available evidence might suggest that vitamin D administration worsens the risk for stone formation in patients predisposed to hypercalciuria. In this review, we analyzed and discussed available literature on the effect of calcium and vitamin D supplementation on the risk for kidney stone formation.

Triglyceride-Glucose Index as a Novel Biomarker in the Occurrence of Kidney Stones: A Cross-Sectional Population-Based Study

Background

Triglyceride–glucose (TyG) index has been considered as the reliable marker of insulin resistance (IR), which is one risk factor of kidney stone. This study aimed to evaluate the TyG index in the occurrence of kidney stones among the United States (US) population.

Methods

Participants who received assessment were retrieved from the National Health and Nutrition Examination Survey (NHANES) between 2007 and 2018. The logistic regression analysis was conducted to assess the relationship between the TyG index and kidney stones occurrence. A 1:1 matched-pair analysis was established to optimize the bias in kidney stones by propensity score matching (PSM). The dose–response curve was performed to verify the association between the TyG index and risk of kidney stones.

Results

Of the 14,158 eligible enrolled participants, 1346 (9.5%) self-reported a history of kidney stones. All participants were divided into two groups (high TyG index group and low TyG index group) based on the median TyG index. The dose–response curve exhibited a positive non-linear correlation between the TyG index and kidney stones risk. High TyG index was related to increased kidney stones occurrence in participants, with adjusted odds ratios (AOR) of 1.14 (95% confidence intervals (CI): 1.01–1.30, P = 0.038) compared with the low TyG index subgroup before PSM. After PSM, the risk of kidney stones was 19% higher in the high TyG group compared with the low TyG group (AOR = 1.19, 95% CI: 1.02–1.38, P = 0.026), and the dose–response curve still showed a positive association between TyG index and kidney stone risk.

Conclusion

The TyG index was independently associated with kidney stones and would be a novel biomarker in predicting occurrence for clinical decision.

Educational Case: Urinary Stones

The following fictional case is intended as a learning tool within the Pathology Competencies for Medical Education (PCME), a set of national standards for teaching pathology. These are divided into three basic competencies: Disease Mechanisms and Processes, Organ System Pathology, and Diagnostic Medicine and Therapeutic Pathology. For additional information, and a full list of learning objectives for all three competencies, seehttp://journals.sagepub.com/doi/10.1177/2374289517715040. ¹

Impact of Plasma Xanthine Oxidoreductase Activity on the Mechanisms of Distal Symmetric Polyneuropathy Development in Patients with Type 2 Diabetes

To unravel associations between plasma xanthine oxidoreductase (XOR) and diabetic vascular complications, especially distal symmetric polyneuropathy (DSP), we investigated plasma XOR activities using a novel assay. Patients with type 2 diabetes mellitus (T2DM) with available nerve conduction study (NCS) data were analyzed. None were currently taking XOR inhibitors. XOR activity of fasting blood samples was assayed using a stable isotope-labeled substrate and LC-TQMS. JMP Clinical version 5.0. was used for analysis. We analyzed 54 patients. Mean age was 64.7 years, mean body mass index was 26.0 kg/m², and mean glycated hemoglobin was 9.4%. The logarithmically transformed plasma XOR activity (ln-XOR) correlated positively with hypoxanthine, xanthine, visceral fatty area, and liver dysfunction but negatively with HDL cholesterol. ln-XOR correlated negatively with diabetes duration and maximum intima-media thickness. Stepwise multiple regression analysis revealed ln-XOR to be among selected explanatory factors for various NCS parameters. Receiver operating characteristic curves showed the discriminatory power of ln-XOR. Principal component analysis revealed a negative relationship of ln-XOR with F-waves as well as positive relationships of ln-XOR with hepatic steatosis and obesity-related disorders. Taken together, our results show plasma XOR activity to be among potential disease status predictors in T2DM patients. Plasma XOR activity measurements might reliably detect pre-symptomatic DSP.

Effect of Carnosine on the Course of Experimental Urate Nephrolithiasis

The prospect of using the antioxidant dipeptide carnosine for the treatment of urate nephrolithiasis was evaluated. Urate nephrolithiasis was modeled in rats by intragastric administration of a mixture of oxonic and uric acids. Carnosine was administered intragastrically through a tube in a dose of 15 mg/kg. In rats treated with carnosine, the concentration of TBA-reactive products decreased by 1.4 times, the total antioxidant activity increased by 1.4 times, and catalase activity increased by 1.3 times. By the end of the experiment, the lactate dehydrogenate level in experimental rats was 2-fold lower than in the control, and the number of urate deposits decreased by 1.6 times with a concomitant alleviation of the inflammatory processes. Thus, the use of direct peptide antioxidant carnosine attenuated the manifestations of urate nephrolithiasis.