Association of uric acid with kidney function and albuminuria: the Uric Acid Right for heArt Health (URRAH) Project

Disparity of serum uric acid threshold for CKD among hypertensive and non-hypertensive individuals

INTRODUCTION

Hypertension and rising serum uric acid (sUA) played a pivotal role in the development of Chronic Kidney Disease (CKD). This study investigates the interactive effect of sUA and hypertension on CKD and identifies the optimal threshold of sUA among individuals with and without hypertension in the Chinese community population.

MATERIALS AND METHODS

The study included 4180 individuals aged 45-85 years, derived from the China Health and Retirement Longitudinal Study (CHARLS) between 2011 and 2015. Additionally, a hospital-based study enrolled subjects in the Department of Nephrology at Zhongshan Hospital, China from January 1, 2019, to December 31, 2021. The interaction effect analysis were used to assess the impact of sUA and hypertension on CKD. We also compared the distribution of sUA and the CKD risk in community populations, distinguishing between those with and without hypertension. For the hospital-based population, kidney injury was marked by a KIM-1 positive area.

RESULTS

Our results indicate a higher prevalence of CKD in the community population with hypertension (10.2% vs. 3.9%, p < .001). A significant additive synergistic effects of the sUA and hypertension on the CKD risk were found. When the sUA level was < 4.55 mg/dL in the hypertensive population and < 5.58 mg/dL in the non-hypertensive population, the risk of CKD was comparable (p = .809). In the propensity score matched (PSM) population, the result remained roughly constant.

CONCLUSION

Therefore, even moderate levels of sUA was associated with a higher risk of CKD in middle-aged hypertensive patients, who warrant stricter sUA control.

Management of hypertension addressing hyperuricaemia: introduction of nano-based approaches

Uric acid (UA) levels in blood serum have been associated with hypertension, indicating a potential causal relationship between high serum UA levels and the progression of hypertension. Therefore, the reduction of serum UA level is considered a potential strategy for lowering and mitigating blood pressure. If an individual is at risk of developing or already manifesting elevated blood pressure, this intervention could be an integral part of a comprehensive treatment plan. By addressing hyperuricaemia, practitioners may subsidize the optimization of blood pressure regulation, which illustrates the importance of addressing UA levels as a valuable strategy within the broader context of hypertension management. In this analysis, we outlined the operational principles of effective xanthine oxidase inhibitors for the treatment of hyperuricaemia and hypertension, along with an exploration of the contribution of nanotechnology to this field.

Dissecting the risk factors for hyperuricemia in vegetarians in Taiwan

BACKGROUND

Vegetarian diets have been shown to lower the risks of hyperuricemia and gout. Little is known about the risk factors of hyperuricemia in vegetarians.

METHODS

This community-based retrospective case-control study was conducted to establish prediction models for hyperuricemia. From September 5, 2005, to December 31, 2016, 7331 adult vegetarians were recruited at Taipei Tzu Chi Hospital. Hyperuricemia was defined as a serum uric acid concentration greater than 7 mg/dL.

RESULTS

There were 593 (8.1%) vegetarians with hyperuricemia and 6738 (91.9%) without hyperuricemia. We stepwise built up three models for predicting hyperuricemia in vegetarians. The full model (model 3) has the highest area under the receiver operating characteristic curve (AUROC, 85.52%). Additionally, the AUROC of model 3 is 77.97% and 84.85% in vegetarians with or without prior gout history, respectively. Moreover, male gender, hyperlipidemia, body mass index, and serum albumin are independent risk factors for hyperuricemia in vegetarians. In contrast, estimated glomerular filtration rate and proteinuria are independently associated with lower risks of hyperuricemia in vegetarians.

CONCLUSION

Our study revealed that risk factors for hyperuricemia, which includes clinical characteristics, account for more than 85% of discriminatory performance in Taiwanese vegetarians. This model may be helpful for monitoring and preventing hyperuricemia in the population.

Hyperuricaemia-associated all-cause mortality risk effect is increased by non-impaired kidney function - Is renal hyperuricaemia less dangerous?

BACKGROUND

Both hyperuricaemia and chronic kidney disease are known mortality risk factors. This study examined the modifying effect of renal function on hyperuricaemia-associated mortality risk, which is an issue that has not been studied before.

METHODS

Data on levels of serum uric acid (SUA), creatinine, cystatin C and other variables of persons aged 52-76 years were collected. Persons with SUA >410 μmol/L (75th percentile) were classified as clearly hyperuricaemic and persons with eGFR of ≤67 ml/min (25th percentile) as having reduced kidney function.

RESULTS

Reduced kidney function was associated with higher mortality in both SUA groups. When compared to individuals with SUA ≤410 μmol/L and eGFR >67 ml/min the hazard ratio (HR) for all-cause mortality was 1.53 (95 % CI: 1.26-1.84) in clearly hyperuricaemic persons with reduced kidney function, 1.26 (95 % CI: 1.02-1.55) in clearly hyperuricaemic persons with eGFR of >67 ml/min and 1.15 (95 % CI: 0.96-1.39) in persons with SUA ≤410 μmol/L and reduced kidney function. The HR for hyperuricaemia-related premature death was lowest in individuals with reduced eGFR, and it rose strikingly as the eGFR increased above 90 ml/min.

CONCLUSIONS

Reduced kidney function is a risk factor for mortality both in individuals with normal and elevated SUA. The hyperuricaemia-associated mortality risk is remarkably higher in individuals with normal kidney function than in individuals with reduced kidney function. Presumably overproduction of uric acid (metabolic hyperuricaemia) is a separate and more deleterious entity than hyperuricaemia resulting from reduced renal excretion of uric acid (renal hyperuricaemia).

Novel function of MOTS-c in mitochondrial remodelling contributes to its antiviral role during HBV infection

OBJECTIVE

Hepatitis B virus (HBV) infection causes substantial harm to mitochondrial activity, which hinders the development of effective treatments for chronic hepatitis B (CHB). The discovery of the mitochondrial-derived short peptide MOTS-c, which possesses multiple bioactivities, offers a promising new approach in treating HBV infection. This study aims to explore the diagnostic and therapeutic potential of MOTS-c in HBV-related diseases and its molecular mechanism.

DESIGN

In total, 85 healthy subjects and 404 patients with HBV infection, including 20 clinical treatment cohorts, were recruited for this study. MOTS-c levels were measured by ELISA and its diagnostic value was evaluated by receiving operating characteristic curve analysis. The therapeutic effect of MOTS-c was observed in multiple HBV-infected mice and cells through various techniques, including transcriptomic sequencing, flow cytometry, immunofluorescence and electron microscopy. Additionally, MOTS-c's potential interaction with myosin-9 (MYH9) and actin was predicted using immunoprecipitation, proteomics and target prediction software.

RESULTS

MOTS-c negatively correlates with HBV DNA expression (R=-0.71), and its AUC (the area under the curve) for distinguishing CHB from healthy controls is 0.9530, and IA (immune reactive) from IC (inactive HBV carrier) is 0.8689. Inhibition of HBV replication (with a 50-70% inhibition rate) was observed alongside improved liver function without notable toxicity in vitro or in vivo. MOTS-c was found to promote mitochondrial biogenesis and enhance the MAVS (mitochondrial antiviral signalling protein) signalling pathway. The impact is dependent on MOTS-c's ability to regulate MYH9-actin-mediated mitochondrial homeostasis.

CONCLUSION

MOTS-c has the potential to serve as a biomarker for the progression of HBV infection while also enhancing antiviral efficacy. These findings present a promising innovative approach for effectively treating patients with CHB. Furthermore, our research uncovers a novel role for MOTS-c in regulating MYH9-actin-mediated mitochondrial dynamics and contributing to mitochondrial biogenesis.

Analysis of the prevalence and influencing factors of hyperuricemia in children and adolescents aged 6-17 years in northeastern Sichuan Province

OBJECTIVE

To investigate the factors influencing hyperuricemia in children and adolescents and to provide a scientific basis for early prevention and treatment.

METHODS

A retrospective study (2017-2021) of the prevalence of hyperuricemia in children and adolescents was conducted, and the factors influencing hyperuricemia were analyzed by multi-factor logistic regression.

RESULTS

The overall prevalence of hyperuricemia in children and adolescents aged 6-17 years in northeast Sichuan Province was 55.12% (8676/15,739), of which 60.68% (5699/9392) in boys and 46.90% (2977/6347) in girls; the prevalence of hyperuricemia from 2017 to 2021 was 52.40% ( 1540/2939), 52.56% (1642/3124), 52.11% (1825/3502), 58.33% (1691/2899), and 60.40% (1978/3275), respectively; the prevalence rates of 6-12 years old were 48.92% (864/1766), 50.46% (769/1524), and 52.73% (685/1299), 56.99% (693/1216), 35.46% (444/1252), 46.33% (524/1131), 60.50% (720/1190), and 66.82% (739/1106), 58.95% (652/1106), and 62.17% (761/1106) for 13-17 years old, respectively, 62.17% (761/1224), 63.19% (855/1353), and 61.70% (970/1572), respectively. Logistic regression showed that the prevalence of male (OR = 1.451, 95% CI 1.034 to 2.035, p = 0.031), age (OR = 1.074, 95% CI 1.024 to 1.126, p = 0.003), overweight/obesity (OR = 1.733, 95% CI 1.204∼2.494, p = 0.003), blood creatinine (OR = 1.018, 95% CI 1.005∼1.031, p = 0.007), triglycerides (OR = 1.450, 95% CI 1.065∼1.972, p = 0.018), blood calcium (OR = 6.792, 95% CI 1.373∼33.594, p = 0.019), and systolic blood pressure (OR = 1.037, 95% CI 1.018∼1.057, p < 0.001) were influential factors for the development of hyperuricemia.

CONCLUSION

The prevalence of hyperuricemia was higher in children and adolescents aged 6-17 years in northeastern Sichuan Province, with a higher prevalence in boys than in girls, and the prevalence increased with age.

Central diastolic blood pressure, plasma aldosterone and uric acid are associated with microalbuminuria in essential hypertension: a case-control study

OBJECTIVE

To study the development of microalbuminuria (MAU) in essential hypertension (EHT), we investigated the association of MAU with central blood pressure (CBP), direct renin concentration (DRC), plasma aldosterone (PA), and uric acid (UA).

METHOD

We determined 24 h-urinary albumin excretion (24 h-UAE) in patients with EHT who were hospitalized at TEDA International Cardiovascular Hospital from June 2020 to May 2022. We defined MAU as 24 h-UAE in the range of 30 mg/24 h to 300 mg/24 h. Univariate and multivariate analyses were conducted to determine the associations of MAU with CBP, DRC, PA, and UA in EHT, considering demographic and clinical information. We also plotted receiver operating characteristic curves (ROCs) for predicting MAU using these results.

RESULTS

More than a quarter of patients (26.5%, 107/404, 95% CI: 22.2-31.1%) were diagnosed with MAU in EHT. A higher body mass index (BMI), longer duration of hypertension, and higher severity were associated with MAU. Also, nearly 10% more creatinine levels were recorded in the MAU group than in the control group (69.5 ± 18.7 µmol/L vs. 64.8 ± 12.5 µmol/L, P = 0.004). The increase was also observed for PA (15.5, 9.7-20.6 ng/dL vs. 12.3, 9.0-17.3 ng/dL, P = 0.024) and UA (419.8 ± 105.6 µmol/L vs. 375.1 ± 89.5 µmol/L, P < 0.001) in the MAU group compared to that in the control group. Several variables were associated with MAU, including central diastolic blood pressure (CDBP) (OR = 1.017, 95% CI: 1.002-1.032, P = 0.027), PA (OR = 1.043, 95% CI: 1.009-1.078, P = 0.012) and UA (OR = 1.005, 95% CI: 1.002-1.008, P < 0.001). For MAU prediction, the area under the curve (AUC) was 0.709 (95% CI: 0.662-0.753; P < 0.001) when CDBP, PA, and UA were used in combination, and the optimal probability of the cut-off value was 0.337.

CONCLUSION

We found that CDBP, PA, and UA, used for MAU prediction, might be associated with its development during EHT.

Prevalence and associated factors of hyperuricemia among Chinese patients with diabetes: a cross-sectional study

Background

As a part of metabolic syndrome, hyperuricemia has a higher incidence in patients with diabetes than in the general population owing to various underlying factors.

Objectives

The objective of the present study was to investigate the prevalence of hyperuricemia among patients with diabetes and identify associated factors.

Design

A cross-sectional study.

Methods

Herein, we included patients with diabetes managed at nine healthcare centers in Chenghua District, Chengdu, from February 2021 to November 2021. Clinical data, lifestyle habits, and laboratory data were collected to determine the prevalence and factors associated with hyperuricemia.

Results

In total, we included 1577 patients with diabetes (males, 50.35%; females, 49.65%). The median serum uric acid level was 337.9 μmol/L, and the prevalence of hyperuricemia in patients with diabetes was 21.24%. The prevalence of hyperuricemia in male patients was significantly higher than in females (29.35% in males versus 13.03% in females, p < 0.001). Male patients with obesity (p = 0.006) or triglyceride (TG) ⩾ 1.7 mmol/L (p < 0.001) had a high risk of developing hyperuricemia, and hyperuricemia was negatively associated with estimated glomerular filtration rate (eGFR) ⩾ 60 mL/min/1.73 m2 (p < 0.001), glycosylated hemoglobin (HbA1c) ⩾ 7% (p < 0.001), fenofibrate (p = 0.010), and sodium-glucose cotransporter 2 (SGLT-2) inhibitors (p = 0.035). Considering females, overweight (p = 0.004), alanine transaminase (ALT) > 40 U/L (p < 0.001), and TG ⩾ 1.7 mmol/L (p = 0.015) showed a significant positive correlation with hyperuricemia, while eGFR ⩾ 60 mL/min/1.73 m2 (p < 0.001) was negatively associated with the risk of hyperuricemia.

Conclusion

Hyperuricemia is highly prevalent in patients with diabetes, especially in males. In addition to traditionally associated factors, fenofibrate and SGLT-2 inhibitors were also associated with the risk of hyperuricemia.

Registration

The study protocol was registered in the Chinese Clinical Trial Registry (http://www.chictr.org.cn/), and the registration number was ChiCTR 2100042742.

The Results of the URRAH (Uric Acid Right for Heart Health) Project: A Focus on Hyperuricemia in Relation to Cardiovascular and Kidney Disease and its Role in Metabolic Dysregulation

The relationship between Serum Uric Acid (UA) and Cardiovascular (CV) diseases has already been extensively evaluated, and it was found to be an independent predictor of all-cause and cardiovascular mortality but also acute coronary syndrome, stroke and heart failure. Similarly, also many papers have been published on the association between UA and kidney function, while less is known on the role of UA in metabolic derangement and, particularly, in metabolic syndrome. Despite the substantial number of publications on the topic, there are still some elements of doubt: (1) the better cut-off to be used to refine CV risk (also called CV cut-off); (2) the needing for a correction of UA values for kidney function; and (3) the better definition of its role in metabolic syndrome: is UA simply a marker, a bystander or a key pathological element of metabolic dysregulation?. The Uric acid Right for heArt Health (URRAH) project was designed by the Working Group on uric acid and CV risk of the Italian Society of Hypertension to answer the first question. After the first papers that individuates specific cut-off for different CV disease, subsequent articles have been published responding to the other relevant questions. This review will summarise most of the results obtained so far from the URRAH research project.

Serum uric acid and left ventricular mass index independently predict cardiovascular mortality: The uric acid right for heart health (URRAH) project

A relationship between serum uric acid (SUA) and cardiovascular (CV) events has been documented in the Uric Acid Right for Heart Health (URRAH) study.

AIM

of this study was to investigate the association between SUA and left ventricular mass index (LVMI) and whether SUA and LVMI or their combination may predict the incidence of CV death.

METHODS

Subjects with echocardiographic measurement of LVMI included in the URRAH study (n=10733) were part of this analysis. LV hypertrophy (LVH) was defined as LVMI > 95 g/m2 in women and 115 g/m2 in men.

RESULTS

A significant association between SUA and LVMI was observed in multiple regression analysis in men: beta 0,095, F 5.47, P< 0.001 and women: beta 0,069, F 4.36, P<0.001. During follow-up 319 CV deaths occurred. Kaplan-Meier curves showed a significantly poorer survival rate in subjects with higher SUA (> 5.6 mg/dl in men and 5.1 mg/dl in women) and LVH (log-rank chi-square 298.105; P<0.0001). At multivariate Cox regression analysis in women LVH alone and the combination of higher SUA and LVH but not hyperuricemia alone, were associated with a higher risk of CV death, while in men hyperuricemia without LVH, LVH without hyperuricemia and their combination were all associated with a higher incidence of CV death.

CONCLUSIONS

Our findings demonstrate that SUA is independently associated with LVMI and suggest that the combination of hyperuricemia with LVH is an independent and powerful predictor for CV death both in men and women.

Uric acid en route to gout

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

Non-Haemodynamic Mechanisms Underlying Hypertension-Associated Damage in Target Kidney Components

Arterial hypertension (AH) is a global challenge that greatly impacts cardiovascular morbidity and mortality worldwide. AH is a major risk factor for the development and progression of kidney disease. Several antihypertensive treatment options are already available to counteract the progression of kidney disease. Despite the implementation of the clinical use of renin-angiotensin aldosterone system (RAAS) inhibitors, gliflozins, endothelin receptor antagonists, and their combination, the kidney damage associated with AH is far from being resolved. Fortunately, recent studies on the molecular mechanisms of AH-induced kidney damage have identified novel potential therapeutic targets. Several pathophysiologic pathways have been shown to play a key role in AH-induced kidney damage, including inappropriate tissue activation of the RAAS and immunity system, leading to oxidative stress and inflammation. Moreover, the intracellular effects of increased uric acid and cell phenotype transition showed their link with changes in kidney structure in the early phase of AH. Emerging therapies targeting novel disease mechanisms could provide powerful approaches for hypertensive nephropathy management in the future. In this review, we would like to focus on the interactions of pathways linking the molecular consequences of AH to kidney damage, suggesting how old and new therapies could aim to protect the kidney.

Correlation between the increase in serum uric acid and the rapid decline in kidney function in adults with normal kidney function: a retrospective study in Urumqi, China

BACKGROUND

To examine the association between elevated serum uric acid (SUA) levels and the rapid decline in kidney function by conducting a retrospective cohort study on a physically healthy population in Urumqi, China.

METHODS

A cohort study of 2,802 physically healthy people with a normal estimated glomerular filtration rate (eGFR) was investigated from 2018 to 2021. The examination procedure included using questionnaires, taking physical measurements, and blood sampling. The rapid decline in kidney function was defined as eGFR > 5 mL·min^-1 ·(1.73 m² )^-1 year. The relationship between elevated SUA levels and the rapid decline in kidney function was assessed.

RESULTS

When performing the three-year retrospective analysis, 688 (28.55%) cases experienced a rapid decline in kidney function, and 52 (1.9%) cases developed chronic kidney disease (CKD). They were divided into the stable group and the rapidly declining kidney function group according to eGFR > 15 mL·min^-1·(1.73 m² )^-1. The comparison revealed a greater increase in uric acid in the rapidly declining kidney function group [0.30 (-0.29, 0.82) mg/dL vs. - 0.07(-0.54, 0.37) mg/dL, Z = - 8.822, P < 0.001]. The participants were further divided into four groups according to their uric acid levels in 2018 and 2021, which included the normal to normal (N-N) group, the normal to hyperuricemia (HUA) (N-H) group, the HUA to normal (H-N) group, and the persistently HUA (H-H) group. The decrease in eGFR was significantly higher in the N-H group than in the other three groups (χ² = 20.580, P < 0.001). The results of the multifactorial logistic regression analysis showed that elevated uric acid was a risk factor for the rapid decline in kidney function (OR = 1.640, P < 0.001).

CONCLUSION

Elevated SUA levels were a risk factor for the rapid decline in kidney function in the Chinese health examination population. Higher SUA levels might predict the occurrence of progressive kidney impairment.

Serum Uric Acid Predicts All-Cause and Cardiovascular Mortality Independently of Hypertriglyceridemia in Cardiometabolic Patients without Established CV Disease: A Sub-Analysis of the URic acid Right for heArt Health (URRAH) Study

High serum uric acid (SUA) and triglyceride (TG) levels might promote high-cardiovascular risk phenotypes across the cardiometabolic spectrum. However, SUA predictive power in the presence of normal and high TG levels has never been investigated. We included 8124 patients from the URic acid Right for heArt Health (URRAH) study cohort who were followed for over 20 years and had no established cardiovascular disease or uncontrolled metabolic disease. All-cause mortality (ACM) and cardiovascular mortality (CVM) were explored by the Kaplan-Meier estimator and Cox multivariable regression, adopting recently defined SUA cut-offs for ACM (≥4.7 mg/dL) and CVM (≥5.6 mg/dL). Exploratory analysis across cardiometabolic subgroups and a sensitivity analysis using SUA/serum creatinine were performed as validation. SUA predicted ACM (HR 1.25 [1.12-1.40], p < 0.001) and CVM (1.31 [1.11-1.74], p < 0.001) in the whole study population, and according to TG strata: ACM in normotriglyceridemia (HR 1.26 [1.12-1.43], p < 0.001) and hypertriglyceridemia (1.31 [1.02-1.68], p = 0.033), and CVM in normotriglyceridemia (HR 1.46 [1.23-1.73], p < 0.001) and hypertriglyceridemia (HR 1.31 [0.99-1.64], p = 0.060). Exploratory and sensitivity analyses confirmed our findings, suggesting a substantial role of SUA in normotriglyceridemia and hypertriglyceridemia. In conclusion, we report that SUA can predict ACM and CVM in cardiometabolic patients without established cardiovascular disease, independent of TG levels.

The association among uric acid, microalbumin and estimated glomerular filtration rate in hypertensive patients: a case control study

OBJECTIVE

To estimate the relationship among uric acid (UA), 24-h microalbumin (24 h-MAU) and estimated glomerular filtration rate (eGFR) in hypertensive patients.

METHOD

The study enrolled adult patients hospitalized in TEDA International Cardiovascular Hospital. The study was used to explore the correlation among UA, 24 h-MAU and eGFR. Univariate analysis was used to compare continuous or categorical data groups according to data type. Multivariate analysis was used to explore the correlation among UA, Log 24 h-MAU and eGFR by linear regression, and the relationship among UA, 24 h-MAU ≥ 30 mg/24 h (increased 24 h-MAU) and eGFR < 90 ml·min^-1·1.73 m^-2 (mildly decreased eGFR) by logistic regression. Mediation effect analysis was used to explore the mediating effect of increased 24 h-MAU between UA and mildly decreased eGFR. Subgroup analysis was used to investigate the correlation among UA, 24 h-MAU and eGFR in different gender.

RESULT

Seven hundred and thirty-three inpatients were enrolled in the study, including 257 patients with hyperuricemia. The level of UA was 377.8 ± 99.9 μmol/L in all patients enrolled, and it was about 50.1% higher in hyperuricemia group (482.3 ± 58.8 μmol/L vs. 321.4 ± 63.5 μmol/L, P < 0.001). The prevalence of hyperuricemia was 35.1% (95%CI 31.6-38.5%). The univariate regression analysis showed that UA was significant related to Log 24 h-MAU, increased 24 h-MAU, eGFR and mildly decreased eGFR. After adjusted confounding factors, UA was significant related to Log 24 h-MAU (β = 0.163, P < 0.001), eGFR (β = - 0.196, P < 0.001), increased 24 h-MAU (quantitative analysis: OR = 1.045, 95%CI 1.020-1.071, P < 0.001; qualitative analysis: OR = 2.245, 95%CI 1.410-3.572, P = 0.001), but had no significant relationship with mildly decreased eGFR. Mediating effect analysis showed that increased 24 h-MAU partially mediated the relationship between UA and mildly decreased eGFR (relative indirect effect: 25.0% and 20.3% in quantitative analysis and qualitative analysis respectively). In the subgroup analysis, the results were stable and similar to the analysis for entry patients.

CONCLUSION

The prevalence of hyperuricemia was higher in hypertensive inpatients. UA was strongly associated with Log 24 h-MAU, eGFR and increased 24 h-MAU, while the correlation with mildly decreased eGFR was affected by multiple factors. And increased 24 h-MAU might be the intermediate factor between UA and mildly decreased eGFR.

The Bidirectional Relationship between Chronic Kidney Disease and Hyperuricemia: Evidence from a Population-Based Prospective Cohort Study

BACKGROUND

Although several studies have examined the association between chronic kidney disease (CKD) and hyperuricemia (HUA), the direction of the association remains unclear. We aimed to investigate whether there was a bidirectional association between them.

METHODS

The present study was conducted in three analyses. Analysis I included 25,433 participants free of HUA at baseline to evaluate the associations between CKD and estimated glomerular filtration rate (eGFR) with incident HUA. Analysis II had 28,422 participants free of CKD at baseline to analyze the relationships between HUA and serum uric acid (sUA) with new-onset CKD. Cox proportional hazards regression models were applied to evaluate the association involved in Analysis I and II. Analysis III included 31,028 participants with complete data and further dissected the bidirectional association between sUA and eGFR using cross-lag models.

RESULTS

New-onset HUA and CKD were observed in the first round of the follow-up study among 1597 and 1212 participants, respectively. A significantly higher risk of HUA was observed in individuals with CKD compared to individuals without CKD (HR = 1.58, 95% CI: 1.28-1.95). The adjusted HRs (95% CIs) of HUA were 3.56 (2.50-5.05) for the participants in the group of eGFR less than 60 mL·min^-1·1.73 m^-2, 1.61 (1.42-1.83) for those in the group of eGFR between 60 and 90 mL·min^-1·1.73 m^-2, and 1.74 (1.42-2.14) for those in the group of eGFR more than 120 mL·min^-1·1.73 m^-2, compared with the group of eGFR between 90 and 120 mL·min^-1·1.73 m^-2. A higher risk of CKD was also observed in individuals with HUA compared to individuals without HUA (HR = 1.28, 95% CI: 1.12-1.47). Compared with the first quintile of sUA, the adjusted HR (95% CI) of CKD was 1.24 (1.01-1.51) for the participants in the fourth quantile. There was a bidirectional relationship between sUA and eGFR, with the path coefficients (ρ₁ = -0.024, p < 0.001) from baseline eGFR to follow-up sUA and the path coefficients (ρ₂ = -0.015, p = 0.002) from baseline sUA to follow-up eGFR.

CONCLUSIONS

The present study indicated that CKD and HUA were closely associated, and there was a bidirectional relationship between sUA and eGFR.

Chronic kidney disease: Which role for xanthine oxidoreductase activity and products?

The present review explores the role of xanthine oxidoreductase (XOR) in the development and progression of chronic kidney disease (CKD). Human XOR is a multi-level regulated enzyme, which has many physiological functions, but that is also implicated in several pathological processes. The main XOR activities are the purine catabolism, which generates uric acid, and the regulation of cell redox state and cell signaling, through the production of reactive oxygen species. XOR dysregulation may lead to hyperuricemia and oxidative stress, which could have a pathogenic role in the initial phases of CKD, by promoting cell injury, hypertension, chronic inflammation and metabolic derangements. Hypertension is common in CKD patients and many mechanisms inducing it (upregulation of renin-angiotensin-aldosterone system, endothelial dysfunction and atherosclerosis) may be influenced by XOR products. High XOR activity and hyperuricemia are also risk factors for obesity, insulin resistance, type 2 diabetes and metabolic syndrome that are frequent CKD causes. Moreover, CKD is common in patients with gout, which is characterized by hyperuricemia, and in patients with cardiovascular diseases, which are associated with hypertension, endothelial dysfunction and atherosclerosis. Although hyperuricemia is undoubtedly related to CKD, controversial findings have been hitherto reported in patients treated with urate-lowering therapies.

Cardio-respiratory and phenotypic rescue of dystrophin/utrophin-deficient mice by combination therapy

Duchenne muscular dystrophy (DMD) is a systemic progressive muscular disease caused by frame-disrupting mutations in the DMD gene. Although exon-skipping antisense oligonucleotides (AOs) are clinically approved and can correct DMD, insufficient muscle delivery limits efficacy. If AO activity can be enhanced by safe dietary supplements, clinical trials for efficacy can be undertaken rapidly to benefit patients. We showed previously that intravenous glycine enhanced phosphorodiamidate morpholino oligomer (PMO) delivery to peripheral muscles in mdx mice. Here, we demonstrate that the combination of oral glycine and metformin with intravenous PMO enhances PMO activity, dystrophin restoration, extends lifespan, and improves body-wide function and phenotypic rescue of dystrophin /utrophin double knock-out (DKO) mice without any overt adverse effects. The DKO mice treated with the combination without altering the approved administration protocol of PMO show improved cardio-respiratory and behavioral functions. Metformin and glycine individually are ineffective in DMD patients, but the combination of PMO with clinically-approved oral glycine and metformin might improve the efficacy of the treatment also in DMD patients. Our data suggest that this combination therapy might be an attractive therapy for DMD and potentially other muscle diseases requiring systemic treatment with AOs.

A systematic review and meta-analysis of the association between uric acid levels and chronic kidney disease

The function of uric acid (UA) in the genesis and evolution of chronic kidney disease (CKD) has motivated numerous studies, but the results remain inconclusive. We sought to conduct a systematic review and meta-analysis of cohort studies aiming to analyze the association of UA levels with the incidence and progression of CKD. Pubmed/Medline, Lilacs/Bireme and Web of Science were searched to identify eligible studies, following the PRISMA protocol. Data were presented for CKD incidence and progression separately. For the meta-analysis, studies with data stratified by subgroups according to serum UA levels were selected. The inverse variance-weighted random effects model was used to generate a combined effect estimate. Meta-regressions were performed to identify the causes of heterogeneity. The Newcastle-Ottawa Scale was used to assess the risk of bias. The publication bias was tested by funnel plot and Egger's test. Eighteen CKD incidence studies (n = 398,663) and six CKD progression studies (n = 13,575) were included. An inverse relationship was observed between UA levels and protection from CKD incidence and progression. Lower UA levels were protective for the risk of CKD incidence (RR 0.65 [95% CI 0.56-0.75]) and progression (RR 0.55 [95% CI 0.44-0.68]). UA seems to be implicated both in the genesis of CKD and its evolution.

Uric acid lowering for slowing CKD progression after the CKD-FIX trial: a solved question or still a dilemma?

Hyperuricemia has been associated with several cardiovascular risk factors and is a well-known predictor of kidney disease. In vitro studies as well as animal models highlighted a role for uric acid in the development and progression of haemodynamic and tissue damage at the renal level leading to glomerular and tubulointerstitial abnormalities. Urate-lowering treatment, especially by xanthine oxidase inhibitors, has been proposed in order to improve kidney outcomes. However, recent randomized controlled trials failed to demonstrate a beneficial effect of allopurinol or febuxostat on renal disease, casting doubts on the role of this therapeutical approach to improve nephroprotection. We provide a critical overview of current literature on this topic and offer a possible interpretation of results from recent intervention trials with urate-lowering treatment on renal outcomes.

Urate-lowering therapy for CKD patients with asymptomatic hyperuricemia without proteinuria elucidated by attribute-based research in the FEATHER Study

Attribute-based medicine is essential for patient-centered medicine. To date, the groups of patients with chronic kidney disease (CKD) requiring urate-lowering therapy are clinically unknown. Herein, we evaluated the efficacy of febuxostat using a cross-classification, attribute-based research approach. We performed post hoc analysis of multicenter, randomized, double-blind, placebo-controlled trial data for 395 patients with stage 3 CKD and asymptomatic hyperuricemia. Participants were divided into febuxostat or placebo groups and subcohorts stratified and cross-classified by proteinuria and serum creatinine concentrations. In patients stratified based on proteinuria, the mean eGFR slopes were significantly higher in the febuxostat group than in the placebo group (P = 0.007) in the subcohort without proteinuria. The interaction between febuxostat treatment and presence of proteinuria in terms of eGFR slope was significant (P for interaction = 0.019). When cross-classified by the presence of proteinuria and serum creatinine level, the mean eGFR slopes significantly differed between the febuxostat and placebo groups (P = 0.040) in cross-classified subcohorts without proteinuria and with serum creatinine level ≥ median, but not in the cross-classified subcohorts with proteinuria and serum creatinine level < median. Febuxostat mitigated the decline in kidney function among stage 3 CKD patients with asymptomatic hyperuricemia without proteinuria.

Uric Acid and Impairment of Renal Function in Non-diabetic Hypertensive Patients

Hyperuricemia is a risk factor for renal impairment. However, investigations focusing on patients with hypertension are limited and inconsistent. A single-center prospective cohort study of 411 Han Chinese non-diabetic hypertensive patients was conducted in Taiwan. The mean age of the participants was 62.0 ±14.4 years. The baseline estimated glomerular filtration rate and uric acid level were 86 mL/min/1.73 m² and 6.2 mg/dL, respectively. All patients underwent serum biochemistry tests for creatinine levels every 3 months. Renal events were defined as >25% and >50% decline in estimated glomerular filtration rate. During an average follow-up period of 4.7 ± 2.9 years (median 4.0 years), a >25 and >50% decline in estimated glomerular filtration rate was noted in 52 and 11 patients, respectively. The multivariate Cox regression analysis revealed that a baseline uric acid level ≥8.0 mg/dL increased the risk of >25% decline (hazard ratio: 3.541; 95% confidence interval: 1.655–7.574, P = 0.001) and >50% decline (hazard ratio: 6.995; 95% confidence interval: 1.309–37.385, P = 0.023) in estimated glomerular filtration rate. Similarly, a baseline uric acid level ≥7.5 mg/dL was independently associated with >25% decline (hazard ratio: 2.789; 95% confidence interval: 1.399–5.560, P = 0.004) and >50% decline (hazard ratio: 6.653; 95% confidence interval: 1.395–31.737, P = 0.017). However, this was not demonstrated at baseline uric acid level ≥7.0 mg/dL. Our study suggests that hyperuricemia is an independent risk factor for the decline in renal function in patients with hypertension. Uric acid level ≥7.5 mg/dL may be considered as the optimal cutoff value for clinical practice in predicting the development of renal impairment.

The Association between Baseline, Changes in Uric Acid, and Renal Failure in the Elderly Chinese Individuals: A Prospective Study with a 3-Year Follow-Up

OBJECTIVE

The objective is to find whether serum uric acid (SUA) levels are associated with the progression of chronic kidney disease (CKD) remains uncertain, and follow-up data among the elderly population are relatively lacking, especially in China. The aim of the present study was to reveal the association between baseline SUA levels, changes in SUA levels, and renal failure in Chinese elderly adults.

METHODS

In this retrospective cohort study, 425 subjects (age range 71-100 years) were analyzed and divided into quartiles based on baseline SUA levels (Q1: <4.8; Q2: <5.7; Q3: <6.5; and Q4: ≥6.5 mg/dl). CKD was defined as estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m². We used multiple linear and logistic regressions to compare the risk of renal dysfunction among the different SUA level groups.

RESULTS

The prevalence of hyperuricemia was 24.24% in the elderly subjects. In the multivariable analysis, the odds ratio (OR) for the development of CKD increased with the increase in SUA quartiles at baseline (1.00 vs. 1.79 (95% CI, 1.00-3.22), 3.4 (95% CI, 1.79-6.47), and 6.79 (95% CI, 3.45-13.75), respectively; P for linear trend <0.001), and a per unit increase in baseline SUA levels gave an OR of 1.76 (95% CI, 1.45-2.14) for renal failure. At the same time, a change in SUA levels had a stronger inverse correlation with a change in eGFR in females (r = -0.318, P < 0.001) than in males (r = -0.187, P < 0.01). In a linear regression analysis, a 1 mg/dl increase in SUA levels was associated with an additional 1.25 (95% CI, -1.83 to -0.67) ml/min/1.73 m² decrease in eGFR over a 3-year period.

CONCLUSION

Elevated baseline SUA levels and changes in SUA levels were associated with a decline in eGFR and an increased risk of CKD in an elderly Chinese population.

Inequalities in enrollment of women and racial minorities in trials testing uric acid lowering drugs

AIMS

We investigated sex and racial inequalities in clinical trials testing serum uric acid (SUA) lowering drugs and analyzed the temporal trends of participation among the pre-specified demographic groups. Data were collected from publications of clinical trials testing SUA-lowering drugs. Linear regression analysis was performed to assess the relation between drug approval year and proportion of women and minorities enrolled in clinical studies.

DATA SYNTHESIS

The mean percentage enrollment of women in clinical trials significantly decreased over the time (r = -0.43, P-value = 0.02). Moreover, there was a statistically significant difference in mean percentage enrollment of women among trials testing different SUA-lowering drugs, with the highest representation in rasburicase (71.1%) and the lowest representation of women in dotinurad (0.8%). Over the time, also the mean percentage enrollment of racial minorities decreased, passing from 8.7% to 2.2% in a 10-year period. Women were proportionally underrepresented compared with their share of the population with asymptomatic hyperuricemia, overall (participation-to-prevalence ratio (PPR) = 0.34), in trials testing xanthine oxiase inhibitors (PPR = 0.38) and uricosurics (PPR = 0.29), and in trials with febuxostat, allopurinol, pegloticase, halofenate/arhalofenate, verinurad, lesinurad and dotinurad. Women were proportionally underreppresented also compared with their share of the population with gout, overall (PPR = 0.69) and in trials testing XOIs (PPR = 0.69), uricosurics (PPR = 0.68), and all SUA-lowering drugs excepted for rasburicase, pegloticase and topiroxostat.

CONCLUSIONS

Our analysis shows that women and racial and ethnical minorities are underrepresented in controlled clinical trials testing SUA-lowering drugs, with similar pattern across drug classes.

The Role of Uric Acid in Acute and Chronic Coronary Syndromes

Uric acid (UA) is the final product of the catabolism of endogenous and exogenous purine nucleotides. While its association with articular gout and kidney disease has been known for a long time, new data have demonstrated that UA is also related to cardiovascular (CV) diseases. UA has been identified as a significant determinant of many different outcomes, such as all-cause and CV mortality, and also of CV events (mainly Acute Coronary Syndromes (ACS) and even strokes). Furthermore, UA has been related to the development of Heart Failure, and to a higher mortality in decompensated patients, as well as to the onset of atrial fibrillation. After a brief introduction on the general role of UA in CV disorders, this review will be focused on UA's relationship with CV outcomes, as well as on the specific features of patients with ACS and Chronic Coronary Syndrome. Finally, two issues which remain open will be discussed: the first is about the identification of a CV UA cut-off value, while the second concerns the possibility that the pharmacological reduction of UA is able to lower the incidence of CV events.

Serum Uric Acid and Kidney Disease Measures Independently Predict Cardiovascular and Total Mortality: The Uric Acid Right for Heart Health (URRAH) Project

Background: Serum uric acid predicts the onset and progression of kidney disease, and the occurrence of cardiovascular and all-cause mortality. Nevertheless, it is unclear which is the appropriate definition of hyperuricemia in presence of chronic kidney disease (CKD). Our goal was to study the independent impact of uric acid and CKD on mortality. Methods: We retrospectively investigated 21,963 patients from the URRAH study database. Hyperuricemia was defined on the basis of outcome specific cut-offs separately identified by ROC curves according to eGFR strata. The primary endpoints were cardiovascular and all-cause mortality. Results: After a mean follow-up of 9.8 year, there were 1,582 (7.20%) cardiovascular events and 3,130 (14.25%) deaths for all causes. The incidence of cardiovascular and all-cause mortality increased in parallel with reduction of eGFR strata and with progressively higher uric acid quartiles. During 215,618 person-years of follow-up, the incidence rate for cardiovascular mortality, stratified based on eGFR (>90, between 60 and 90 and <60 ml/min) was significantly higher in patients with hyperuricemia and albuminuria (3.8, 22.1 and 19.1, respectively) as compared to those with only one risk factor or none (0.4, 2.8 and 3.1, respectively). Serum uric acid and eGFR significantly interact in determining cardiovascular and all-cause mortality. For each SUA increase of 1 mg/dl the risk for mortality increased by 10% even after adjustment for potential confounding factors included eGFR and the presence of albuminuria. Conclusions: hyperuricemia is a risk factor for cardiovascular and all-cause mortality additively to eGFR strata and albuminuria, in patients at cardiovascular risk.

Association of uric acid and uric acid to creatinine ratio with chronic kidney disease in hypertensive patients

Background

Recent studies have shown that the serum uric acid/creatinine ratio (SUA/SCr) is a better predictor of chronic kidney disease (CKD) than serum uric acid (SUA) isolated. The aim of the present study was to evaluate the association of isolated SUA and the SUA/SCr with CKD in hypertensive patients.

Methods

Cross-sectional study conducted with hypertensive patients followed-up by the Primary Health Care Service (PHC). Sociodemographic, economic, lifestyle, clinical, anthropometric, and biochemical variables were evaluated. The association between SUA parameters (quartiles of SUA and quartiles of SUA/SCr) and CKD was evaluated by bivariate and multivariate logistic regression. The association between SUA parameters (SUA and SUA/SCr) and estimated glomerular filtration rate (eGFR) was evaluated by linear regression. The analyses were performed considering four adjustment models. SUA and SUA/SCr were compared by receiver operating characteristic (ROC) curve.

Results

In the fully adjusted model, SUA was positively associated with the presence of CKD (OR = 6.72 [95 % CI 1.96–22.96]) and inversely associated with eGFR (β Coef. = -2.41 [95 % CI -3.44; -1.39]). SUA/SCr was positively associated with eGFR (β Coef. = 2.39 [1.42; 3.36]). According to the ROC curve, the SUA is a better predictor of CKD than the SUA/SCr.

Conclusions

Elevated levels of isolated SUA were associated with CKD and eGFR. However, the SUA/SCr was not associated with CKD. We do not recommend using the SUA/SCr to predict CKD in hypertensive patients.

Hyperuricemia and Progression of Chronic Kidney Disease: A Review from Physiology and Pathogenesis to the Role of Urate-Lowering Therapy

The relationship between hyperuricemia, gout, and renal disease has been investigated for several years. From the beginning, kidney disease has been considered a complication of gout; however, the viewpoints changed, claiming that hypertension and elevated uric acid (UA) levels are caused by decreased urate excretion in patients with renal impairment. To date, several examples of evidence support the role of hyperuricemia in cardiovascular or renal diseases. Several mechanisms have been identified that explain the relationship between hyperuricemia and chronic kidney disease, including the crystal effect, renin-angiotensin-aldosterone system activation, nitric oxide synthesis inhibition, and intracellular oxidative stress stimulation, and urate-lowering therapy (ULT) has been proven to reduce renal disease progression in the past few years. In this comprehensive review, the source and physiology of UA are introduced, and the mechanisms that explain the reciprocal relationship between hyperuricemia and kidney disease are reviewed. Lastly, current evidence supporting the use of ULT to postpone renal disease progression in patients with hyperuricemia and gout are summarized.

Effect of Berberine on Hyperuricemia and Kidney Injury: A Network Pharmacology Analysis and Experimental Validation in a Mouse Model

Purpose

Berberine (BBR) is an active component of Phellodendri Cortex (PC), which is a traditional Chinese medicine that has been prescribed clinically for hyperuricemia (HUA) for hundreds of years. Many studies reported the anti-inflammatory and nephroprotective properties of BBR and PC; however, the therapeutic effects of BBR on HUA have not been explored. This study aims to investigate the efficacy and mechanism of BBR for treating HUA.

Methods

The mechanism of BBR in the treatment of HUA were predicted by network pharmacology. A mouse model of HUA established by potassium oxonate and hypoxanthine was used to verify the prediction. The levels of serum uric acid (UA), urea nitrogen (BUN) and creatinine (CRE) were determined by biochemical test kits. Hematoxylin and eosin staining of kidney tissues was used to observe the kidney damage. ELISA kits were applied to detect the levels of interleukin (IL)-1β and IL-18 in serum and kidney tissues. Quantitative real-time PCR and Western blotting were adopted to analyze the expression of NLRP3, ASC, Caspase1, IL-1β and URAT1. The expressions of URAT1 in the kidney tubules were visualized by immunohistochemical staining. Molecular docking was used to assess the interaction between URAT1 and BBR.

Results

The network pharmacology screened out 82 genes and several inflammation-related signaling pathways related to the anti-hyperuricemia effect of BBR. In the in vivo experiment, BBR substantially decreased the level of UA, BUN and CRE, and alleviated the kidney damage in mice with HUA. BBR reduced IL-1β and IL-18, and downregulated expressions of NLRP3, ASC, Caspase1 and IL-1β. BBR also inhibited expression of URAT1 and exhibited strong affinity with this target in silico docking.

Conclusion

BBR exerts anti-HUA and nephroprotective effects via inhibiting activation of NLRP3 inflammasome and correcting the aberrant expression of URAT1 in kidney. BBR might be a novel therapeutic agent for treating HUA.

Association Between Low-Dose Aspirin and Uric Acid in the Elderly: An Observational Retrospective Cross-Sectional Study

Purpose

Uric acid is an independent factor for arteriosclerotic cardiovascular disease (ASCVD). Although aspirin is one of the most widely used agent in patients with ASCVD, there were only a few studies focusing on the effects of low-dose aspirin on uric acid metabolism with controversial results. The present study aimed to investigate an association between low-dose aspirin treatment for more than one month and serum uric acid (SUA) with its urinary excretion in elderly patients.

Patients and Methods

This paper presents an observational retrospective cross-sectional study to determine the association between continuous daily taking low-dose aspirin (50–100mg) for more than one month and SUA with fraction excretion of uric acid (FEUA) in elderly patients. A total of 506 inpatients equal or over 60 in Department of Geriatrics of Peking University First Hospital were enrolled from 2017 to 2020. About 41.9% of them were taking aspirin for more than one month, while others were not taking this medicine. The correlation between aspirin use and SUA or FEUA was analyzed, and group-comparison was performed in different dosage groups of aspirin.

Results

After correcting confounding factors, there is no remarkable correlation between taking low-dose aspirin and SUA or FEUA, but a decreasing trend (coefficients=−4.946) of SUA in hyperuricemia patients with low-dose aspirin was observed despite no obvious difference (P=0.534). Whether SUA or FEUA has no significant difference between 50mg/d and 100mg/d aspirin subjects.

Conclusion

SUA and urinary uric acid excretion are not associated with using of 50–100mg/d aspirin for more than one month in elderly patients with ASCVD or at risk.

Relationship between uric acid and kidney function in adults at risk for tumor lysis syndrome

Uric acid drives acute kidney injury in tumor lysis syndrome (TLS). This study investigated the relationship between uric acid and changes in estimated glomerular filtration rate (eGFR) in adults at risk for TLS. Linear regression was used to evaluate the relationship between uric acid area under the curve (AUC) and percent change in eGFR from baseline at hospital dismissal, 1 and 3 months. In 210 included participants, each 100 mg*hour/dL increase in 24 h AUC was associated with an average decline in eGFR at hospital dismissal of 9% (95%CI 3, 15) in univariate analysis. Each 100 mg*hour/dL increase in 24 h AUC was independently associated with an average decline in eGFR of 8% (95%CI 2, 13) at 1 month after dismissal. Additional research is needed to confirm these findings and determine whether treatments that reduce overall uric acid exposure improve kidney outcomes. Preserving kidney health could favorably impact cancer treatment eligibility, tolerability, and outcomes.