Febuxostat Therapy for Patients With Stage 3 CKD and Asymptomatic Hyperuricemia: A Randomized Trial

Comparative efficacy and safety of febuxostat and allopurinol in chronic kidney disease stage 3-5 patients with asymptomatic hyperuricemia: a network meta-analysis

OBJECTIVE

This study evaluates and compares the effectiveness and safety of febuxostat and allopurinol in chronic kidney disease (CKD) stages 3-5 patients with asymptomatic hyperuricemia using a network meta-analysis.

METHODS

A systematic review and network meta-analysis were conducted, adhering to PRISMA-NMA guidelines. Searches included PubMed, Embase, Cochrane Library, and Chinese databases up to June 2024. Randomized controlled trials (RCTs) and cohort studies were assessed for methodological rigor using GRADE.

RESULTS

A total of 12 RCTs and 4 cohort studies (n = 2,423 participants) were included. Febuxostat was associated with greater improvements in estimated glomerular filtration rate compared to allopurinol (MD, 4.99 mL/min/1.73 m2; 95%CI -0.65 to 10.78; certainty: low) and placebo (MD, 4.72 mL/min/1.73 m2; 95%CI 0.67 to 8.82; low). Serum uric acid reduction was also more pronounced with febuxostat (MD, -0.61 mg/dL; 95%CI -1.15 to -0.05; moderate). Safety outcomes, including major cardiovascular events and adverse events, showed no significant differences between febuxostat and allopurinol. Subgroup analyses revealed enhanced effectiveness of febuxostat at six months of treatment.

CONCLUSIONS

This analysis provides robust evidence that febuxostat might offers greater improvements in kidney function and uric acid levels compared to allopurinol or placebo in asymptomatic hyperuricemia with CKD stage 3-5 patients, without compromising safety. These findings can guide clinical decision-making and treatment optimization.

Evaluation and Management of Chronic Kidney Disease: Synopsis of the Kidney Disease: Improving Global Outcomes 2024 Clinical Practice Guideline

DESCRIPTION

The Kidney Disease: Improving Global Outcomes (KDIGO) organization updated its existing clinical practice guideline in 2024 to provide guidance on the evaluation, management, and treatment of chronic kidney disease (CKD) in adults and children who are not receiving kidney replacement therapy.

METHODS

The KDIGO CKD Guideline Work Group defined the scope of the guideline and determined topics for systematic review. An independent Evidence Review Team systematically reviewed the evidence and graded the certainty of evidence for each of the review topics. Latest searches of the English-language literature were done in July 2023. Final modification of the guideline was informed by a public review process during summer of 2023 involving registered stakeholders.

RECOMMENDATIONS

The full guideline included 28 recommendations and 141 practice points. This synopsis focuses on the recommendations that have the greatest evidence. Practice points reflect the expert opinion of the group where evidence is not that strong. Recommendations include greater emphasis on cystatin C for assessment of glomerular filtration rate, point-of-care testing in remote areas, a shift to an individualized risk-based approach to predict kidney failure, sodium-glucose cotransporter-2 inhibitors for some patients with CKD with and without diabetes, and statin use for adults older than 50 years and CKD. Together the recommendations and practice points provide guidance for how to evaluate and manage persons with CKD.

Association of Chronic Kidney Disease With Increased Glucose Uptake-Associated Metabolic Activity of Visceral Adipose and Subcutaneous Adipose Tissue in Patients With Gout

OBJECTIVE

We evaluate the 18F-fluorodeoxyglucose positron emission tomography (PET) standardized uptake value (SUV) by PET/computed tomography (CT) scans in visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) in patients with and without gout. Additionally, we investigate whether glucose uptake in these tissues predicts the progression of chronic kidney disease (CKD).

METHODS

We used International Classification of Diseases, Tenth Revision codes from the University of California San Diego patient database to identify patients with gout and controls, forming a cohort of individuals who underwent PET/CT scans. The mean VAT and SAT maximum SUV (SUVmax) were measured using PET/CT scans and adjusted for potential confounders using inverse probability of weighting analysis. We also employed multivariable linear regression to analyze changes in estimated glomerular filtration rate (eGFR) after PET/CT scans.

RESULTS

The study included 221 patients, with 120 diagnosed with gout. After the inverse probability of weighting adjustment, the mean VAT and SAT SUVmax were higher in patients with gout (mean VAT SUVmax: β = 0.09, 95% confidence interval [CI] 0.04-0.15; mean SAT SUVmax: β = 0.06, 95% CI 0.01-0.12). Additionally, in patients with gout with CKD stage ≥3, higher mean VAT and SAT SUVmax were associated with decreased eGFR in the 5 years following PET/CT scans (mean VAT SUVmax: β = -1.76, 95% CI -3.50 to -0.01; mean SAT SUVmax: β = -2.97, 95% CI -5.61 to -0.32).

CONCLUSION

Elevated glucose uptake-associated metabolic activity in both VAT and SAT was observed in patients with gout, which may contribute to CKD progression among patients with both gout and CKD.

Efficacy of febuxostat on hyperuricemia and estimated glomerular filtration rate in patients with non-dialysis stage 3/4 chronic kidney disease and assessment of cardiac function: a 12-month interventional study

Objectives

Febuxostat, an oral medication for treating hyperuricemia (HUA), is a non-purine xanthine oxidase inhibitor that regulates serum uric acid (SUA) metabolism in patients with chronic kidney disease (CKD). However, the drug's effectiveness in improving renal function in patients with non-dialysis stage 3/4 CKD remains unclear. Our aim is to investigate the efficacy of febuxostat on kidney function. In addition, the cardiac function will be assessed.

Method

We conducted a single-center, interventional, randomized, controlled, open-label study. A total of 316 patients with non-dialysis stage 3/4 CKD, with SUA ≥6mg/dL in women and ≥7mg/dL in men, were assigned to either the febuxostat group (n=156) or the control group (n=160). The primary endpoint was the evaluation of changes in kidney biomarkers from baseline to 12 months of treatment, and any changes in cardiac biomarkers and echocardiographs were the secondary endpoint.

Results

The primary endpoint was a comparison between the two groups from baseline to 12 months of treatment. SUA was significantly decreased in patients treated with febuxostat 40 mg (6.85 ± 0.41mg/dL at baseline and 5.27 ± 0.70mg/dL at 12 months of treatment, P<0.001) and this was associated with increased eGFR (34.48 ± 8.42ml/min at baseline and 38.46 ± 8.87ml/min at 12 months of treatment, P<0.001). There were significant decreases in high-sensitivity troponin T (19.50 ± 7.24ng/L at baseline and 16.98 ± 7.32ng/L at 12 months of treatment, P<0.001) and N-terminal-pro brain natriuretic peptide (941.35 ± 374.30pg/ml at baseline and 762.22 ± 303.32 pg/ml at 12 months of treatment, P<0.001) in the febuxostat group. These changes were also associated with increased left ventricular ejection fraction in the febuxostat group (50.47 ± 3.95% at baseline and 51.12 ± 3.96% at the end of the study, P<0.001).

Conclusion

In the interventional group, febuxostat was well-tolerated and demonstrated a reduction in SUA associated with an increase in eGFR. This slowed down the progression of renal disease in patients with non-dialysis stage 3/4 CKD and improved cardiac function.

Comparative assessment of the effects of dotinurad and febuxostat on the renal function in chronic kidney disease patients with hyperuricemia

Although hyperuricemia is associated with chronic kidney disease (CKD), the impact of uric acid (UA)-lowering drugs on CKD has been controversial. Previous investigations have primarily included xanthine oxidase inhibitors; therefore, research of dotinurad, a recently developed selective urate reabsorption inhibitor, is necessary. This retrospective study included 58 patients with CKD; of these, 29 newly initiated dotinurad and 29 initiated febuxostat. The effects of dotinurad and febuxostat on the serum UA, urinary UA-to-creatinine ratio (UUCR), and estimated glomerular filtration rate (eGFR) during 3 months were analyzed to compare their impacts on renal function. Dotinurad and febuxostat decreased serum UA (8.40 ± 1.11 to 6.50 ± 0.80 mg/dL [p < 0.001] and 8.91 ± 1.21 to 6.05 ± 1.28 mg/dL [p = < 0.001], respectively). The UUCR increased after dotinurad (0.35 ± 0.15 to 0.40 ± 0.21 g/gCr [p = 0.024]); however, it decreased after febuxostat (0.33 ± 0.12 to 0.21 ± 0.06 g/gCr [p = 0.002]). The eGFR improved after dotinurad (33.9 ± 15.2 to 36.2 ± 15.9 mL/min/1.73 m2 [p < 0.001]). No change was observed after febuxostat treatment (33.4 ± 19.6 to 34.1 ± 21.6 mL/min/1.73 m2). Renal function improved only with dotinurad, thus highlighting its renoprotective effects beyond the reduction of serum UA.

Two still unanswered questions about uric acid and cardiovascular prevention: Is a specific uric acid cut-off needed? Is hypouricemic treatment able to reduce cardiovascular risk?

AIMS

The most frequent consequence of elevated uric acid (UA) levels is the development of gout and urate kidney disease. Besides these effects, several studies have investigated the association between hyperuricemia and cardiovascular (CV) disease. High serum UA has been identified as an important determinant of all-cause and CV mortality and CV events (acute and chronic coronary syndrome, stroke and peripheral artery disease). Despite the high number of publications on this topic, there are two questions that are still unanswered: do we need a specific CV cut-off of serum UA to better refine the CV risk? Is urate lowering treatment (ULT) able to reduce CV risk in asymptomatic patients? In this review, we will focus on these two points.

DATA SYNTHESIS

Although no doubt exists that the relationship between CV events starts at lower levels than the actually used cut-off, different papers found dissimilar cut-offs. Furthermore, heterogeneity is present depending on the specific CV events evaluated and none of the found cut-off have been tested in external populations (in order to confirm its discriminatory capacity). Furthermore, only few randomized clinical trials on the role of hypouricemic agents in reducing the CV risk have been published giving heterogeneous results. The last published one (ALL-HEART) has strong limitations, that we will deeply discuss.

CONCLUSIONS

A definitive answer to the two questions is impossible with the actually published paper but, over identifying current gaps in knowledge we try to individuate how they can be overruled.

Post-hoc analysis of the CARES trial suggests delayed progression of chronic kidney disease in patients with gout during urate-lowering therapy

Based on the hypothesis that hyperuricemia is a modifiable risk factor for chronic kidney disease (CKD) progression, there is an expectation that urate-lowering therapy (ULT) could delay the progression of CKD. Here, we investigated changes in kidney function and the association of the serum uric acid (sUA) level and kidney function during ULT in patients with gout. To do this we conducted post-hoc analysis on patients who received ULT with either febuxostat or allopurinol for more than six months in the CARES trial. The estimated glomerular filtration rate (eGFR) slope (annual rate of change in eGFR) was calculated using the CKD-EPI creatinine equation and linear mixed modeling. Among the 5,002 patients with gout, 3,264 (65.3%) demonstrated an increased eGFR while receiving ULT over a median follow-up of 2.5 years. Increased average sUA levels were significantly associated with declines in eGFR slope (per 1 mg/dL increase, (adjusted beta of -0.1912). Propensity score matched analysis demonstrated a significant association between low average sUA levels below 6 mg/dL during ULT and a reduced risk of eGFR decline (adjusted odds ratio: 0.66, 95% confidence interval 0.57-0.77). Despite the well-documented natural decline of eGFR over time in the general population, more than half of the patients enrolled in the CARES trial did not experience declines in eGFR while receiving ULT. Thus, our study shows maintaining low sUA levels with ULT was significantly associated with a decreased risk of CKD progression in patients with gout.

Association between urate-lowering therapy and kidney failure in patients with chronic kidney disease

BACKGROUND

Hyperuricemia is a hallmark of gout and a suspected risk factor for the progression of chronic kidney disease (CKD). However, the impact of urate-lowering therapy on CKD progression is subject to debate. The objective of the present study was to describe the prevalence of inappropriate urate-lowering therapy prescriptions and evaluate the association between urate-lowering therapy prescription and the progression of kidney disease in patients with CKD.

METHODS

CKD-REIN is a French, nationwide, prospective cohort of 3,033 nephrology outpatients with CKD (eGFR < 60 mL/min/1.73 m2). Prescriptions of urate-lowering therapy drugs (allopurinol or febuxostat) were recorded prospectively. The appropriateness of each prescription was evaluated according to the patient's kidney function at baseline and during follow-up. Propensity score-matched, cause-specific Cox proportional hazards regression models were used to assess the association between incident urate-lowering therapy use and CKD progression (defined as the initiation of kidney replacement therapy (KRT) but also in other ways).

RESULTS

At baseline, 987 of the 3009 patients included in this study (median age: 69; men: 66%) were receiving urate-lowering therapy; 396 of these 987 patients were receiving an inappropriate prescription with regard to their kidney function. During a 5-year follow-up period, 70% of the 396 urate-lowering therapy prescriptions remained inappropriate. In the propensity score-matched cohort (n = 674), 136 patients started KRT. Compared with non- urate-lowering therapy use, urate-lowering therapy use was not significantly associated with a slowing in CKD progression, regardless of the definition used (HRKRT 0.89, 95% CI 0.67-1.20).

CONCLUSIONS

Our real-world data emphasized the lack of reassessment of urate-lowering therapy prescriptions in patients with CKD. Urate-lowering therapy was not associated with a slowing of CKD progression.

Reno-protective effects of xanthine oxidase inhibitors in patients with type 2 diabetes and chronic kidney disease: a systematic review and meta-analysis

BACKGROUND

The effect of lowering uric acid levels on renal function in patients with diabetic kidney disease remains unclear. Previous randomized controlled trials (RCTs) have reported conflicting results regarding the effects of xanthine oxidase inhibitors on renal function. This study aimed to examine the renoprotective effects of xanthine oxidase inhibitors (febuxostat and topiroxostat) in patients with diabetic kidney disease.

METHODS

Relevant RCTs were searched using PubMed, Embase, and Cochrane Central databases. Ultimately, five RCTs were included in the meta-analysis. The assessed renal endpoints included changes in the estimated glomerular filtration rate (eGFR) and urine albumin-to-creatinine ratio. The meta-analysis was conducted using Review Manager version 5.4. Standardized mean differences (SMDs) and 95% confidence intervals (CIs) were calculated for changes in renal endpoints between the groups after the study period. A subgroup analysis was conducted based on the type of intervention, results of the risk of bias assessment, and baseline renal function.

RESULTS

Although the use of febuxostat or topiroxostat did not induce a significant change in eGFR compared with the placebo, it showed a tendency to delay renal function decline (SMD = 0.32, 95% CI = [- 0.00; 0.64]). There was no significant difference in albuminuria between the two groups (SMD = 0.26, 95% CI = [- 0.10; 0.62]).

CONCLUSIONS

This study suggests the potential of febuxostat or topiroxostat to delay renal function decline in patients with diabetes and underlying renal impairment, that needs to be confirmed in further studies.

TRIAL REGISTRATION

INPLASY registration number 202450024.

Associations of Serum Urate and Cardiovascular Events in a Clinical Trial of Interleukin-1β Blockade

BACKGROUND

Serum urate (SU) associates with cardiovascular (CV) events, mortality, and gout.

OBJECTIVES

The purpose of this study was to assess whether SU predicts CV risk in a trial of interleukin (IL)-1β inhibition with canakinumab, and whether IL-1β blockade, kidney function, or gout alter these associations.

METHODS

This study is a subanalysis of the Canakinumab Antiinflammatory Thrombosis Outcome Study (CANTOS), which randomized 10,061 patients with prior myocardial infarction and elevated high-sensitivity C-reactive protein to 3 doses of canakinumab or placebo. SU was measured at baseline. Cox proportional hazards models compared major adverse cardiovascular events (MACE), CV death, and all-cause mortality among those with SU ≤6.8 mg/dL (normal), 6.8 to 9.0 mg/dL (elevated), and ≥9.0 mg/dL (markedly elevated). Cox regressions were repeated within subgroups, including canakinumab vs placebo, estimated glomerular filtration rate ≥60 vs <60 mL/min, and gout vs no gout.

RESULTS

Markedly elevated SU associated with MACE (HR: 1.66 [95% CI: 1.38-1.99]; P < 0.0001), CV death (HR: 2.52 [95% CI: 1.98-3.21]; P < 0.0001), and all-cause mortality (HR: 2.43 [95% CI: 2.01-2.94]; P < 0.0001) compared to normal SU. After multivariable adjustment for a minimal set of potential confounders, SU independently predicted all 3 endpoints. Associations were unchanged after IL-1β blockade with canakinumab. For normal estimated glomerular filtration rate, SU associated with CV and all-cause mortality, but not MACE. Participants with gout had higher event rates independent of SU.

CONCLUSIONS

In over 10,000 patients with coronary artery disease, individuals with markedly elevated SU have elevated CV risk despite aggressive treatment. IL-1β blockade did not modify these associations. Baseline kidney function and monosodium urate deposition may function as effect modifiers.

Can we crystallize the role of urate-lowering treatment in chronic kidney disease?

The therapeutic value of serum urate lowering in chronic kidney disease is questionable given the lack of clinical benefit from randomized clinical trials. Post hoc analysis of the CARES (Cardiovascular Safety of Febuxostat and Allopurinol in Patients with Gout and Cardiovascular Morbidities) trial suggests a protective effect of urate lowering in gout participants over 2.5 years of follow-up with the greatest benefit for those who maintained average urate levels of <6 mg/dl. A shift in research focus from asymptomatic hyperuricemia to symptomatic hyperuricemia may yet yield dividends.

The role of hyperuricemia in the progression of end-stage kidney disease and its molecular prospective in inflammation and cardiovascular diseases: A general review

With the ongoing development of the Chinese economy, the occurrence of chronic kidney disease (CKD) has experienced a remarkable upsurge recently, and due to uremia caused by CKD, the number of patients undergoing dialysis has shown a dramatic increase. China has been ranked first in the world for patients undergoing hemodialysis (HD) and peritoneal dialysis (PD) with approximately one million patients across the country. Due to the loss of kidney function caused by CKD, the kidneys tend to lose their ability to excrete uric acid (UA) out of the body; therefore, most patients undergoing dialysis are complicated with hyperuricemia (HUA). HUA is an abnormal disease of purine metabolism, and it's considered a chronic disease. More than 90% of patients suffering from HUA will not show any symptoms on physical examination. According to statistics, if high serum UA is left untreated, 55% of patients will develop severe problems due to the purine crystallization in the body, and the kidneys are the most affected organs by HUA causing renal insufficiency that can promote end-stage kidney disease (ESKD) by activating the renin-angiotensin system (RAS), which will lead to inflammation, arteriosclerosis, cardiovascular diseases (CVD), and other diseases. Lifestyle modifications and pharmacological interventions are the first primary choice for lowering UA, although dialysis will tend to reduce the high UA levels in the blood, drugs are also necessary. This review will summarize the mechanisms and metabolism of UA, the relationship between HUA and ESKD progression, HUA and inflammation, HUA and CVD, and pharmacological treatment of HUA.

Systemic inflammation response index association with gout in hyperuricemic adults: NHANES 2007-2018

Background

Hyperuricemia is the underlying condition of gout. Previous studies have indicated that specific strategies may be effective in preventing the progression of hyperuricemia to gout. However, there is a lack of widely applicable methods for identifying high-risk populations for gout. Gout is linked to inflammation, especially in the hyperuricemic population. Systemic inflammation response index (SIRI) is a novel method for evaluating an individual's systemic inflammatory activity. However, the association between SIRI and gout in the hyperuricemic population has not been studied.

Methods

The study utilized data from the National Health and Nutrition Examination Survey (NHANES) 2007-2018.SIRI was log2-transformed before analysis. Multivariable logistic regression, subgroup analysis, and smooth curve fitting were employed to comprehensively evaluate the correlation between SIRI and gout prevalence in the hyperuricemic population. Additionally, we compared SIRI with other inflammatory markers.

Result

A total of 6,732 hyperuricemic patients were included, of which 3,764 were men. After adjusting for all covariates, SIRI was found to be significantly positively correlated with gout prevalence in the female group ([OR = 1.385, 95% CI (1.187, 1.615), p < 0.001]), and its diagnostic performance was superior to other inflammatory markers. In the male group, the correlation between log2-SIRI and gout prevalence was not significant ([OR = 0.994, 95% CI (0.892, 1.108), p = 0.916]). But there were significant positive correlations in the 20-45 age group ([OR = 1.362, 95% CI (1.021, 1.818), p = 0.036]). Subgroup analyses revealed that the results were largely consistent when the individuals were divided into different subgroups (FDR adjusted p for interaction >0.05 for all).

Conclusion

Our study suggests that the Systemic Inflammation Response Index (SIRI) has potential as a predictive marker for gout risk in hyperuricemic women. However, given the higher gout prevalence in men, the potential of SIRI as a predictive marker for gout risk in this population may be limited. Subgroup analyses, however, indicated that the relationship between SIRI and gout prevalence, as well as its statistical significance, varied across different age groups. Future research could further explore this association by investigating the relationship between SIRI and gout prevalence in different age cohorts.

Asymptomatic Hyperuricemia and the Kidney: Lessons from the URRAH Study

Chronic kidney disease (CKD) is a prevalent global health concern affecting approximately 850 million people worldwide, with a significant and rising mortality rate. CKD often coexists with hyperuricemia (HSUA), which is also increasingly common due to its association with hypertension, obesity, and diabetes. The interplay between hyperuricemia and CKD is complex; while in vitro studies and animal models support a role for uric acid mediating glomerular and tubule-interstitial damage, and HSUA has been shown to predict the onset and progression of CKD, the expectations of renal protection by the use of urate lowering treatment (ULT) are inconsistent. A significant challenge in managing asymptomatic HSUA in CKD patients lies in determining the appropriate SUA threshold values. Recent research, including the URRAH project, has sought to identify SUA cut-offs predictive of cardiovascular mortality, but these thresholds may vary depending on the severity of CKD. This variability complicates the establishment of universal guidelines for treating asymptomatic HSUA, leading to a lack of specific recommendations in clinical practice. In conclusion, while hyperuricemia is recognized as a prognostic factor for CKD and cardiovascular risk, more research is needed to refine the threshold values for SUA and to identify which patients may benefit from ULT. Stratification based on glomerular filtration rate may be necessary to tailor the treatments and improve outcomes in this population.

An update on the pharmacotherapy of gout

INTRODUCTION

Gout is a common form of acute inflammatory arthritis caused by the deposition of monosodium urate crystals within synovium of joints. This leads to severe pain, reducing quality of life for patients with this condition.

AREAS COVERED

This review summarizes the treatment of both acute flares of gout and urate-lowering therapy based on guidance from various major international societies. We have also covered new emerging therapies that have not yet reached clinical practice.

EXPERT OPINION

Standard pharmacotherapies for gout flares include the options of colchicine, NSAIDs and oral or intramuscular corticosteroids, with IL-1 inhibitors newly established as an option for flare refractory to standard therapies. Urate-lowering therapies aim to prevent gout flares, with an emphasis on treat-to-target strategy; the escalation of therapies until the target serum uric acid is reached. Initial treatments include allopurinol and febuxostat, with uricosuric agents, probenecid, sulfinpyrazone and benzbromarone, as adjuncts. There are also emerging therapies in development. However, there is increasing personalization of treatment, adjusting pharmacotherapy depending on comorbidities, such as chronic kidney disease and ischemic heart disease, as well as patient preference.

Target Serum Urate Achievement and Chronic Kidney Disease Progression in Patients With Gout and Kidney Disease

Importance

Clinicians often approach urate-lowering therapy (ULT) cautiously in patients with gout and impaired kidney function because they are concerned about the risk of progression to severe or end-stage kidney disease. However, evidence from randomized clinical trials of this association remains inconclusive.

Objective

To evaluate the association between achieving target serum urate level with ULT and progression of chronic kidney disease (CKD) to severe or end-stage in patients with gout and impaired kidney function.

Design, Setting, and Participants

This was a cohort study using the target trial emulation approach using data from a general practice database (IQVIA Medical Research Database) for 2000 to 2023. Eligible patients were 40 to 89 years old and had gout and CKD stage 3. Data analyses were performed from November 2023 to September 2024.

Exposures

Lowering serum urate level to target level (<6 mg/dL) using ULT.

Main Outcomes and Measures

Severe or end-stage kidney disease, determined by an estimated glomerular filtration rate of less than 30 mL/min/1.73 m2 on at least 2 occasions more than 90 days apart within 1 year, or at least 1 Read code (per the Refined Etiology, Anatomical Site, and Diagnosis classification) for CKD stages 4 or 5, hemodialysis, peritoneal dialysis, or kidney transplant. The prespecified noninferiority margin of the hazard ratio (HR) was set at 1.2, comparing those who achieved the target serum urate level with those who did not.

Results

Among the 14 792 participants (mean [SD] age, 73.1 [9.5] years; 9215 men [62.3%] and 5577 women [37.7%]) with gout and with CKD stage 3, the 5-year risk of severe or end-stage kidney disease was 10.32% for those who achieved the target serum urate level and 12.73% for those who did not. Compared with those not achieving the target level, the adjusted 5-year risk difference and HR of severe or end-stage kidney disease for patients achieving the target serum urate level was -2.41% (95% CI, -4.61% to -0.21%) and 0.89 (95% CI, 0.80 to 0.98), respectively.

Conclusions and Relevance

The findings of this cohort study indicate that in patients with gout and CKD stage 3, lowering serum urate level to less than 6 mg/dL vs 6 mg/dL or greater using ULT was not associated with an increased risk of severe or end-stage kidney disease. These findings support optimizing ULT to achieve target serum urate levels when treating patients with gout and impaired kidney function.

Monitoring and Management of Uric Acid Therapy in Gout and Chronic Kidney Disease: A Single-Center Retrospective Study

Background Gout commonly coexists with chronic kidney disease (CKD) due to reduced renal excretion of uric acid (UA). Guidelines recommend regular monitoring and dose adjustment of urate-lowering therapy (ULT), but the rate of adherence to these guidelines is not well established. Our study aimed to determine adherence to ULT guidelines in gout patients at our institution. In particular, we sought to assess the effect of CKD as well as other comorbidities on the prevalence of ULT guideline adherence. Methods We conducted a retrospective cohort study of 5,985 gout patients at our institution initiated on allopurinol between 2015 and 2020. Inclusion criteria were age over 18, a gout diagnosis, and a new allopurinol prescription. The primary outcome was UA monitoring within six months of therapy initiation. A secondary outcome was the prevalence of dose adjustments made by providers in response to a UA level above target. Results Only 48.3% (n = 2,889) of patients had UA levels monitored within six months. CKD stage did not significantly impact monitoring rates (p = 0.059). In patients with elevated UA levels (>6 mg/dL), 54.3% (n = 1,011) of patients had no dosage adjustments. Conclusions Significant gaps exist in adherence to ULT guidelines; nearly half of patients did not undergo recommended UA monitoring. Over half of patients with elevated uric levels did not have dosage adjustments. CKD stage did not affect the likelihood of UA monitoring or dose changes in persons with elevated UA levels.

Febuxostat provides renoprotection in patients with hyperuricemia or gout: a systematic review and meta-analysis of randomized controlled trials

PURPOSE

It is unknown whether febuxostat can delay the progression of kidney dysfunction and reduce kidney endpoint events. The aim was to evaluate the renoprotective effect of febuxostat in patients with hyperuricemia or gout by performing a meta-analysis of randomized controlled trials (RCTs).

METHODS

MEDLINE, Web of science, EMBASE, ClinicalTrials.gov, and the Cochrane Central Register for Randomized Controlled Trials were searched. The main outcomes included kidney events (serum creatinine doubling or progression to end-stage kidney disease or dialysis). The secondary outcomes were the rate of change in the estimated glomerular filtration rate (eGFR) and changes in the urine protein or urine albumin to creatinine ratio from baseline to the end of follow-up. We used random-effects models to calculate the pooled risk estimates and 95% CIs.

RESULTS

A total of 16 RCTs were included in the meta-analysis. In comparison with the control group, the patients who received febuxostat showed a reduced risk of kidney events (RR = 0.56, 95% CI 0.37-0.84, p = 0.006) and a slower decline in eGFR (WMD = 0.90 mL/min/1.73 m2, 95% CI 0.31-1.48, p = 0.003). The pooled results also revealed that febuxostat use reduced the urine albumin to creatinine ratio (SMD = -0.21, 95% CI -0.41 to -0.01, p = 0.042).

CONCLUSION

Febuxostat use is associated with a reduced risk of kidney events and a slow decline in eGFR. In addition, the urine albumin to creatinine ratio decreased in febuxostat users. Accordingly, it is an effective drug for delaying the progression of kidney function deterioration in patients with gout.Systematic review registration: PROSPERO CRD42021272591.

Cardiovascular Outcomes of Uric Acid Lowering Medications: A Meta-Analysis

BACKGROUND

Although hyperuricemia is a recognized risk factor for cardiovascular diseases, mixed results have been reported regarding the associations between uric acid-lowering medications and cardiovascular events. This meta-analysis compared the cardiovascular outcomes of different uric acid-lowering medications and placebo.

METHODS

Following PRISMA guidelines, we searched OVID Medline, Embase, Web of Science, and Cochrane databases to identify potentially relevant articles until December 2023. Studies must be randomized or observational, report cardiovascular and mortality outcomes, and compare uric acid-lowering medications to placebo or each other. Data was analyzed using Revman (version 5.4) software.

RESULTS

A total of 3,393 studies were searched, after which 47 studies were included, totaling 3,803,509 patients (28 studies comparing xanthine oxidase inhibitors (XOI) versus placebo, 17 studies comparing allopurinol and febuxostat, and 2 studies comparing XOI and uricosuric agents). Overall mean age was 57.3 years, and females comprised 20.8% of all studies. There were no significant differences between XOI and placebo for cardiovascular outcomes (mortality, myocardial infarction, major adverse cardiovascular events, heart failure, or arrhythmia). There was significant heterogeneity in all these pooled analyses. Comparing Allopurinol to Febuxostat, there was a lower risk of heart failure in febuxostat than allopurinol in 3 RCTs (OR 0.66, 95% CI 0.50-0.89, p = 0.006). Other cardiovascular outcomes were not different. Lastly, when comparing XOI and uricosuric agents, no significant differences in MI rates were evident.

CONCLUSION

XOI was not associated with reduced cardiovascular events compared to placebo. When comparing XOI agents, Febuxostat might reduce the risk of HF, but future studies are required to confirm the findings from the current study.

Cardiovascular outcomes of urate-lowering therapies in patients with gout or hyperuricemia: a network meta-analysis

BACKGROUND

To evaluate the comparative cardiovascular safety of urate-lowering therapies (ULTs) in patients with gout or hyperuricemia.

RESEARCH DESIGN AND METHODS

Randomized controlled trials (RCTs) for ULTs with reported cardiovascular outcomes were included. Pairwise and network random-effect meta-analyses were performed to obtain the odds ratios (ORs) with 95% confidence intervals (CIs). The surface under the cumulative ranking curve (SUCRA) was employed to assess and rank the cardiovascular safety of ULTs.

RESULTS

A total of 3,663 literature were retrieved, of which 26 RCTs involving 25,329 patients were finally included. Pairwise and network meta-analyses showed that allopurinol demonstrated a significant reduction in arrhythmia compared with febuxostat (for pairwise meta-analysis, OR = 0.69, 95%CI 0.49 to 0.97; for network meta-analysis, OR = 0.71, 95%CI 0.51 to 0.99). Nevertheless, there was no statistically significant difference observed in other outcomes between different ULTs or between ULTs and placebo (p > 0.05). According to the SUCRA, febuxostat and pegloticase, had the highest probability of mitigating the occurrence of major adverse cardiovascular events (MACEs) and all-cause mortality respectively.

CONCLUSIONS

Overall, ULTs showed relatively good cardiovascular safety in patients with gout or hyperuricemia. However, febuxostat has a higher risk of arrhythmia compared with allopurinol. Further studies are needed to confirm our findings.

Environmental factors and chronic kidney disease: a case-control study

Chronic kidney disease (CKD) is a non-communicable disease that includes a range of different physiological disorders causing abnormal renal function and progressive decline in the glomerular filtration rate (GFR). This study aimed to investigate the associations of several Environmental factors with CKD in the Iranian population. This is the second phase of a hospital-based case-control study, which was conducted on 700 participants (350 CKD cases and 350 controls, age and gender frequency matched). Multiple logistic regression was applied to measure the associations between the selected factors and CKD. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated. All p-values were two-sided and the results were considered statistically significant at p < 0.05. The results suggested that environmental factors including proximity of residence to mines (OR yes/no=3.98, 95%CI: 2.20-7.21, p < 0.001), proximity of residence to mobile antenna (OR yes/no=2.20, 95%CI: 1.24-3.89, p = 0.006), and exposure to chemicals (OR chemical/no=4.40, 95%CI: 2.27-8.53, p < 0.001), were significantly associated with a higher risk of CKD. The present study covered a large number of factors in association with CKD and highlighted the importance of some environmental factors in development of CKD.‌ One of the main causes of heat in the work environment being a risk factor is dehydration caused by high heat. In order to reduce damage to the kidneys in jobs that deal with high heat, the following tips are recommended: drinking fluids, reducing working hours and shifts, proper ventilation in the workplace, using suitable clothes and heat protection.

Controversies and practical management of patients with gout and chronic kidney disease

Uric acid is a toxin retained with advancing kidney disease. Clinical manifestations of hyperuricemia include gout and systemic inflammation that are associated with increased risk of cardiovascular mortality. As many as one-third of all patients with chronic kidney disease have a history of gout, yet <25% of these patients are effectively treated to target serum urate levels of ≤6 mg/dl. A major reason for ineffective management of gout and hyperuricemia is the complexity in managing these patients, with some medications contraindicated and others requiring special dosing, potential drug interactions, and other factors. Consequently, many nephrologists do not primarily manage gout despite it being a common complication of chronic kidney disease, leaving management to the primary physician or rheumatologist. We believe that kidney specialists should consider gout as a major complication of chronic kidney disease and actively manage it in their patients. Here, we present insights from nephrologists and rheumatologists for a team approach to gout management that includes the nephrologist.

Asymptomatic hyperuricemia: to treat or not a threat? A clinical and evidence-based approach to the management of hyperuricemia in the context of cardiovascular diseases

Asymptomatic hyperuricemia is defined by serum uric acid levels above 6.2 mg/dl in women and 7 mg/dl in men. In the presence of monosodium urate crystal formation and articular inflammation, hyperuricemia may become symptomatic (namely nephrolithiasis and gout). Uric acid results from purine catabolism and is at the centre of a complex metabolic interplay that involves oxidative stress, inflammation, renin-angiotensin-aldosterone system (RAAS) activation and insulin resistance. Uric acid levels present a continuous relation with conditions like hypertension and chronic kidney disease (CKD) and are reported to have an impact on risk of cardiovascular events. However, whether elevated uric acid is a causal agent and thus a possible therapeutic target is still uncertain and matter of further investigation. Treating symptomatic hyperuricemia involves lowering uric acid drugs and controlling inflammation. Urate-lowering agents are well tolerated but show minimal impact on cardiovascular events in patients with gout. Use of direct-acting urate-lowering agents in asymptomatic hyperuricemia associated with cardiovascular diseases does not warrant a clear benefit, whereas addressing cardiovascular issues with guideline-recommended therapies lowers uric acid and reduces the occurrence of cardiovascular events. Regular assessment of uric acid and clinical symptoms is advised before starting and renewing a urate-lowering treatment.

Hypertension and Cardiovascular Risk Among Children with Chronic Kidney Disease

PURPOSE OF REVIEW

Cardiovascular disease is the most common cause of mortality across the lifespan of children with chronic kidney disease (CKD). Hypertension is a common and important contributor, but other factors such as obesity, dyslipidemia and mineral bone disease play a role. This narrative review focusses on studies published in the past five years that have investigated hypertension and cardiovascular risk among children with CKD.

RECENT FINDINGS

Cohort studies such as Chronic Kidney Disease in Children (CKiD) and Cardiovascular Comorbidity in Children with CKD (4C) have continued to develop our understanding of blood pressure (BP) phenotypes, and of progressive changes in the structure and function of the heart and blood vessels occurring in children with CKD. Metabolic risk factors, such as dyslipidemia, may represent an under-recognized component of care. Trial data are less common than observational evidence, but support lifestyle interventions currently used, mainly the low sodium dietary approaches to stop hypertension (DASH) diet. The findings of the recently reported Hypertension Optimal Treatment in Children with Chronic Kidney Disease trial (HOT-KID) are described in relation to the use of office BP treatment targets. Cardiovascular health is critical to the long-term outcomes of children with CKD. Recognizing and treating hypertension remains a critical component to improving outcomes, along with measures to improve concurrent cardiovascular risk factors. Some cardiovascular changes may not be reversible with transplantation and further research is needed for children at all stages of CKD.

Association Between Febuxostat Use and the Incidence of Cardiovascular Events, Mortality, and Kidney Events in Patients With Chronic Kidney Disease Compared to Allopurinol: A Study Using a Japanese Nationwide Database

Background Patients with chronic kidney disease (CKD) were excluded in most trials that investigated the effects of urate-lowering agents, such as febuxostat and allopurinol, in hyperuricemic patients. This exclusion leads to uncertainty regarding the efficacy of febuxostat in patients with CKD. Due to the high prevalence of hyperuricemia in patients with CKD, we aimed to assess the effect of febuxostat on improving patient outcomes concerning cardiovascular events and survival compared with those treated with allopurinol among patients with CKD. Methods We conducted a retrospective cohort study using Japanese nationwide administrative data from Jan 1, 2013, to Sep 30, 2020. Patients aged over 60 years diagnosed with CKD were included in this study if they were prescribed either febuxostat or allopurinol. The primary outcome was the occurrence of cardiovascular events including myocardial infarction, stroke, unstable angina requiring urgent revascularization, and all-cause deaths. We estimated hazard ratios (HR) and 95% CI using a Cox proportional hazard regression model adjusted for comorbidities, medications, and laboratory data. We also assessed defined starting kidney replacement therapy as a secondary endpoint treating death as a competing risk using the Fine & Gray regression model. Results A total of 21,015 patients included those with febuxostat (n=17,796) and those with allopurinol (n=3,219). The association between the type of drug and the occurrence of cardiovascular events did not show a significant difference (0.107 vs. 0.116 events per patient-year; adjusted HR 0.953, 95% CI: 0.854 to 1.062, P=0.381). Similar results were seen for all-cause deaths (0.060 vs. 0.068 events per patient-year; adjusted HR 0.877, 95% CI: 0.760 to 1.012, P=0.073). Regarding the secondary endpoint, the association between the type of drug and the timing of starting kidney replacement therapy did not show a significant difference (0.118 vs. 0.097 events per patient-year; adjusted HR 0.953, 95% CI: 0.854 to 1.062, P=0.425). Conclusion The use of febuxostat was neither associated with a decreased risk of cardiovascular events or deaths nor with the timing of starting kidney replacement therapy compared to the use of allopurinol in patients with CKD.

Hyperuricemia and its related diseases: mechanisms and advances in therapy

Hyperuricemia, characterized by elevated levels of serum uric acid (SUA), is linked to a spectrum of commodities such as gout, cardiovascular diseases, renal disorders, metabolic syndrome, and diabetes, etc. Significantly impairing the quality of life for those affected, the prevalence of hyperuricemia is an upward trend globally, especially in most developed countries. UA possesses a multifaceted role, such as antioxidant, pro-oxidative, pro-inflammatory, nitric oxide modulating, anti-aging, and immune effects, which are significant in both physiological and pathological contexts. The equilibrium of circulating urate levels hinges on the interplay between production and excretion, a delicate balance orchestrated by urate transporter functions across various epithelial tissues and cell types. While existing research has identified hyperuricemia involvement in numerous biological processes and signaling pathways, the precise mechanisms connecting elevated UA levels to disease etiology remain to be fully elucidated. In addition, the influence of genetic susceptibilities and environmental determinants on hyperuricemia calls for a detailed and nuanced examination. This review compiles data from global epidemiological studies and clinical practices, exploring the physiological processes and the genetic foundations of urate transporters in depth. Furthermore, we uncover the complex mechanisms by which the UA induced inflammation influences metabolic processes in individuals with hyperuricemia and the association with its relative disease, offering a foundation for innovative therapeutic approaches and advanced pharmacological strategies.

Impact of hyperuricemia on CKD risk beyond genetic predisposition in a population-based cohort study

The bidirectional effect of hyperuricemia on chronic kidney disease (CKD) underscores the importance of hyperuricemia as a risk factor for CKD. We evaluated the effect of hyperuricemia on the presence and development of CKD after considering genetic background by calculating polygenic risk scores (PRSs). We employed genome-wide association study summary statistics-excluding the United Kingdom Biobank (UKB) datasets among published CKD Gen Consortium papers-to calculate the PRSs for CKD in white background subjects. To validate PRS performance, we divided the UKB into two datasets to validate and test the data. We used logistic regression analysis to evaluate the association between hyperuricemia and CKD, and performed Kaplan-Meier survival analysis exclusively for subjects with available follow-up data. In total, 438,253 clinical data and 4,307,940 single nucleotide polymorphisms from 459,155 samples were included. We observed a significant positive association between PRS and CKD and the presence and development of CKD. Hyperuricemia significantly increased CKD risk (adjusted odds ratio 1.55, 95% confidence interval 1.48-1.61). The impact of hyperuricemia on CKD was maintained irrespective of PRS range. In addition, negative interaction between hyperuricemia and PRS for CKD was found. Survival analysis indicates that the presence of hyperuricemia significantly increased the risk of CKD development. The PRS for CKD thoroughly reflects the risk of CKD development. Hyperuricemia is a significant indicator of CKD risk, even after incorporating the genetic risk score for CKD. Irrespective of genetic risk, patients with a prospective risk of developing CKD require uric acid monitoring and management.

Uric acid and cardiovascular diseases: a reappraisal

Serum uric acid (SUA) has garnered an increased interest in recent years as an important determinant of cardiovascular disease. Uric acid, a degradation product of purine metabolism, is affected by several inheritable and acquired factors, such as genetic mutation, metabolic syndrome, chronic kidney disease, and medication interactions. Even though elevated SUA have been commonly associated with the development of gout, it has significant impact in the development of hypertension, metabolic syndrome, and cardiovascular disease. Uric acid, in both crystalline and soluble forms, plays a key role in the induction of inflammatory cascade and development of atherosclerotic diseases. This concise reappraisal emphasizes key features about the complex and challenging role of uric acid in the development and progression of atherosclerosis and cardiovascular disease. It explores the pathogenesis and historical significance of uric acid, highlights the complex interplay between uric acid and components of metabolic syndrome, focuses on the pro-inflammatory and pro-atherogenic effects of uric acid, as well as discusses the role of urate lowering therapies in mitigating the risk of cardiovascular disease while providing the latest evidence to the healthcare professionals focusing on the clinical importance of SUA levels with regards to cardiovascular disease.

A 23-year-old male patient with Kimura's disease without renal transplantation: a rare case report from Syria

Introduction and importance

Kimura's disease (KD) is a chronic, nonmalignant inflammatory disorder that primarily affects subcutaneous tissue. It is typically characterized by painless nodules in the head and neck regions, accompanied by elevated eosinophil and serum IgE levels. The purpose of this case study is to elucidate this rare disease, particularly in the Asian region and Syria, and to explore diagnostic and therapeutic methodologies with the objective of mitigating the number of undiagnosed patients suffering from this disease.

Case presentation

A 23-year-old male patient presented to the Ear, Nose, and Throat (ENT) Department of the hospital with symptoms that had been initiated 7 months prior. The primary symptoms were pain and swelling in the left preauricular area, followed by subsequent swelling in the right preauricular area the next day. The patient experienced severe, intermittent pain, generalized pruritus, and systemic manifestations, including fever, chills, fatigue, malaise, anorexia, and a weight loss of 20 kg over the course of seven months. A fine-needle aspiration of the left parotid gland revealed the presence of lymphocytes at various maturation stages, with no evidence of abnormal cells. A diagnosis of KD was subsequently confirmed.

Clinical discussion

To our knowledge, this case represents the second documented instance of KD in Syria. Furthermore, our case is among the extremely rare instances of KD in a patient without a history of renal transplantation.

Conclusion

Further research is essential to ascertain the actual prevalence of this condition and to identify the most effective management strategies.

The effect of metabolic factors on the association between hyperuricemia and chronic kidney disease: a retrospective cohort mediation analysis

BACKGROUND

Hyperuricemia, hyperglycemia, hypertension, hyperlipidemia, and hyperhomocysteinemia are all established risk factors for chronic kidney disease (CKD), and their interplay could exacerbate CKD progression. This study aims to evaluate the potential mediation effects of hyperglycemia, hypertension, hyperlipidemia, and hyperhomocysteinemia on the association between hyperuricemia (HUA) and chronic kidney disease (CKD).

METHODS

We collected electronic medical record data from 2055 participants who underwent physical examinations at the Affiliated Hospital of Qingdao University. The data were utilized to investigate the mediating effect of various factors including systolic blood pressure (SBP), diastolic blood pressure (DBP), homocysteine (HCY), triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), blood glucose (Glu), and hemoglobin A1c (HbA1c) on the relationship between HUA and CKD.

RESULTS

Upon adjusting for confounding variables, mediation analysis indicated that only HCY acted as a mediator in the HUA-CKD relationship (p value < 0.05), exhibiting a statistically significant mediation effect of 7.04%. However, after adjustment for multiple testing, none of these variables were statistically significant.

CONCLUSIONS

Considering the observed associations between hyperuricemia, hyperglycemia, hypertension, hyperlipidemia, and CKD, none of the factors of interest remained statistically significant after adjusting for multiple testing as potential mediators of hyperuricemia on CKD.

Emerging Roles of Xanthine Oxidoreductase in Chronic Kidney Disease

Xanthine Oxidoreductase (XOR) is a ubiquitous, essential enzyme responsible for the terminal steps of purine catabolism, ultimately producing uric acid that is eliminated by the kidneys. XOR is also a physiological source of superoxide ion, hydrogen peroxide, and nitric oxide, which can function as second messengers in the activation of various physiological pathways, as well as contribute to the development and the progression of chronic conditions including kidney diseases, which are increasing in prevalence worldwide. XOR activity can promote oxidative distress, endothelial dysfunction, and inflammation through the biological effects of reactive oxygen species; nitric oxide and uric acid are the major products of XOR activity. However, the complex relationship of these reactions in disease settings has long been debated, and the environmental influences and genetics remain largely unknown. In this review, we give an overview of the biochemistry, biology, environmental, and current clinical impact of XOR in the kidney. Finally, we highlight recent genetic studies linking XOR and risk for kidney disease, igniting enthusiasm for future biomarker development and novel therapeutic approaches targeting XOR.

Association of urinary excretion rates of uric acid with biomarkers of kidney injury in patients with advanced chronic kidney disease

BACKGROUND

The potential influence of hyperuricemia on the genesis and progression of chronic kidney disease (CKD) remains controversial. In general, the correlation between blood levels of uric acid (UA) and the rate of progression of CKD is considered to be modest, if any, and the results of relevant trials oriented to disclose the effect of urate-lowering therapies on this outcome have been disappointing. Urinary excretion rates of UA could reflect more accurately the potential consequences of urate-related kidney injury.

METHOD

Using a cross-sectional design, we investigated the correlation between different estimators of the rates of urinary excretion of UA (total 24-hour excretion, mean urinary concentration, renal clearance and fractional excretion)(main study variables), on one side, and urinary levels of selected biomarkers of kidney injury and CKD progression (DKK3, KIM1, NGAL, interleukin 1b and MCP)(main outcome variables), in 120 patients with advanced CKD (mean glomerular filtration rate 21.5 mL/minute). We took into consideration essential demographic, clinical and analytic variables with a potential confounding effect on the explored correlations (control variables). Spearman's rho correlation and nonlinear generalized additive regression models (GAM) with p-splines smoothers were used for statistical analysis.

MAIN RESULTS

Multivariate analysis disclosed independent correlations between urinary UA concentrations, clearances and fractional excretion rates (but not plasma UA or total 24-hour excretion rates of UA), on one side, and the scrutinized markers. These correlations were more consistent for DKK3 and NGAL than for the other biomarkers. Glomerular filtration rate, proteinuria and treatment with statins or RAA axis antagonists were other independent correlates of the main outcome variables.

CONCLUSIONS

Our results support the hypothesis that urinary excretion rates of UA may represent a more accurate marker of UA-related kidney injury than plasma levels of this metabolite, in patients with advanced stages of CKD. Further, longitudinal studies will be necessary, to disclose the clinical significance of these findings.

Impacts of Febuxostat on Cerebral and Cardiovascular Events in Elderly Patients with Hyperuricemia: Post Hoc Analysis of a Randomized Controlled Trial

A recent meta-analysis found no benefit of uric acid-lowering therapy including febuxostat on death, cardiovascular events, or renal impairment. However, there may be populations that benefit from febuxostat in reducing mortality and cerebral and cardiovascular events. The aim of the present study was to examine the clinical benefit of febuxostat in elderly patients stratified by age using Febuxostat for Cerebral and CaRdiorenovascular Events PrEvEntion StuDy (FREED) data. FREED was a randomized study involving patients aged 65 years or older with hyperuricemia and risk factors for cerebral, cardiovascular, or renal diseases. A total of 1,070 patients were included in this post hoc analysis, divided into 2 age groups: 65-74 years and ≥ 75 years. Patients were randomized into febuxostat and non-febuxostat groups, with uric acid levels monitored for 36 months. The primary composite end point included cerebral, cardiovascular, and renal events. In patients aged between 65 and 74 years, febuxostat significantly reduced the risk of future cerebral and cardiorenovascular events. However, no effects of febuxostat were found in the older population aged ≥ 75 years. Heterogeneity in potential interactions between the age and febuxostat treatment was particularly observed in non-fatal cerebral and cardiovascular events and all-cause death. Patients aged ≥ 75 years exhibited more pre-existing factors associated with cerebral and cardiorenovascular events than those aged 65-74 years. The effectiveness of febuxostat varies by age group, with potential benefits for patients aged 65-74 years. The effects of febuxostat are complex and it is important to consider patient characteristics in its clinical use.

Hyperuricemia: An Intriguing Connection to Metabolic Syndrome, Diabetes, Kidney Disease, and Hypertension

PURPOSE OF THE REVIEW

Our review explores the epidemiology, physiology, and clinical data surrounding the connection between hyperuricemia and metabolic syndrome, chronic kidney disease, and hypertension.

RECENT FINDINGS

Compelling physiologic mechanisms have been proposed to explain a causal relationship between hyperuricemia and metabolic syndrome, chronic kidney disease, and hypertension but clinical studies have given mixed results in terms of whether intervening with hyperuricemia using urate-lowering therapy has any beneficial effects for patients with these conditions. Despite the large amount of research already put into this topic, more randomized placebo-controlled trials are needed to more firmly establish whether a cause-effect relationship exists and whether lowering uric acid levels in patients with these conditions is beneficial.

Association of time-averaged serum uric acid level with clinicopathological information and long-term outcomes in patients with IgA nephropathy

Objective

Whether serum uric acid (SUA) at baseline could been identiûed as a risk factor for progression in IgA nephropathy (IgAN) patients remains unclear, therefore, long- term SUA control levels must be monitored. We aimed to investigate the relevant factors affecting time-averaged SUA (TA-SUA) and to assess the prognostic value of TA-SUA in IgAN.

Methods

This retrospective study included 152 patients with IgAN. The relationships between TA-SUA and clinicopathological features and renal outcomes (defined as the doubling of the baseline serum creatinine level or end-stage renal disease) were analyzed in groups divided by quartiles of TA-SUA levels, the presence of hyperuricemia, and sex.

Results

Patients with high TA-SUA levels had higher levels of baseline SUA, blood urea nitrogen (BUN), triglycerides, serum C3 and serum C4 and were more likely to be male and have hypertension, proteinuria, poor renal function, and pathological injuries including high grades of tubular atrophy/interstitial fibrosis (T1-T2). These patients had a poorer prognosis compared with patients with low TA-SUA levels. The TA-SUA level was positively correlated with baseline age and BUN, triglycerides, serum C3, and serum C4 levels, and negatively correlated with baseline eGFR. Survival curve analysis indicated that persistent hyperuricemia was associated with significantly poorer renal outcomes than normo-uricemia in both men and women. The TA-SUA level also was an independent predictor of renal outcome in patients with IgAN, with optimal cutoû values of 451.38 µmol/L (area under the curve (AUC) = 0.934) for men and 492.83 µmol/L (AUC = 0.768) for women.

Conclusions

The TA-SUA level is associated with triglyceride level, complement component levels, renal function, and pathological severity of IgAN, and it may be a prognostic indicator in male and female patients with IgAN.

Timing of Initiation of Xanthine Oxidase Inhibitors Based on Serum Uric Acid Level Does Not Predict Renoprognosis in Patients with Preserved Kidney Function

Background: Despite recent evidence of remaining possibility that early initiation of xanthine oxidase inhibitors (XOIs) is beneficial in renoprognosis for patients with stage 2 or less chronic kidney disease (CKD), no evidence is available regarding the difference in renoprognosis based on serum uric acid (sUA) levels at the initiation of XOIs among patients with preserved kidney function. Methods: New XOI initiators were divided into quartiles based on baseline sUA. Primary outcome was the composite incidence of a significant estimated glomerular filtration rate (eGFR) decline (≥40% decline in eGFR from baseline or development of eGFR <30 mL/1.73 m2/min) or all-cause death within 5 years. Results: After excluding inapplicable patients, 1170 XOI initiators were analyzed (mean ± standard deviation age: 68 ± 14.3 years; sUA: 10.6 ± 1.15 mg/dL). On overall median [interquartile range (IQR)] follow-up of 824 (342, 1576) days, incidence rate of the primary outcome was 287 per 1000 person-years for 5 years. Although the nonadjusted model showed a dose-response association between baseline sUA level and the outcome, the adjusted model showed no significant association. Adjusted hazard ratios (95% confidence interval) of the second, third, and fourth quartiles of baseline sUA with the composite outcome within 5 years compared to the first quartile were 1.00 (0.78, 1.29), 1.00 (0.80, 1.30), and 1.02 (0.80, 1.32), respectively. Conclusions: Early initiation of XOIs did not predict a significant benefit on renoprognosis even among the population with preserved kidney function. The validity of initiating XOIs with the aim of improving renoprognosis based on sUA is questionable.

Allopurinol and blood pressure variability following ischemic stroke and transient ischemic attack: a secondary analysis of XILO-FIST

Blood Pressure Variability (BPV) is associated with cardiovascular risk and serum uric acid level. We investigated whether BPV was lowered by allopurinol and whether it was related to neuroimaging markers of cerebral small vessel disease (CSVD) and cognition. We used data from a randomised, double-blind, placebo-controlled trial of two years allopurinol treatment after recent ischemic stroke or transient ischemic attack. Visit-to-visit BPV was assessed using brachial blood pressure (BP) recordings. Short-term BPV was assessed using ambulatory BP monitoring (ABPM) performed at 4 weeks and 2 years. Brain MRI was performed at baseline and 2 years. BPV measures were compared between the allopurinol and placebo groups, and with CSVD and cognition. 409 participants (205 allopurinol; 204 placebo) were included in the visit-to-visit BPV analyses. There were no significant differences found between placebo and allopurinol groups for any measure of visit-to-visit BPV. 196 participants were included in analyses of short-term BPV at week 4. Two measures were reduced by allopurinol: the standard deviation (SD) of systolic BP (by 1.30 mmHg (95% confidence interval (CI) 0.18-2.42, p = 0.023)); and the average real variability (ARV) of systolic BP (by 1.31 mmHg (95% CI 0.31-2.32, p = 0.011)). There were no differences in other measures at week 4 or in any measure at 2 years, and BPV was not associated with CSVD or cognition. Allopurinol treatment did not affect visit-to-visit BPV in people with recent ischemic stroke or TIA. Two BPV measures were reduced at week 4 by allopurinol but not at 2 years.

Uric acid in health and disease: From physiological functions to pathogenic mechanisms

Owing to renal reabsorption and the loss of uricase activity, uric acid (UA) is strictly maintained at a higher physiological level in humans than in other mammals, which provides a survival advantage during evolution but increases susceptibility to certain diseases such as gout. Although monosodium urate (MSU) crystal precipitation has been detected in different tissues of patients as a trigger for disease, the pathological role of soluble UA remains controversial due to the lack of causality in the clinical setting. Abnormal elevation or reduction of UA levels has been linked to some of pathological status, also known as U-shaped association, implying that the physiological levels of UA regulated by multiple enzymes and transporters are crucial for the maintenance of health. In addition, the protective potential of UA has also been proposed in aging and some diseases. Therefore, the role of UA as a double-edged sword in humans is determined by its physiological or non-physiological levels. In this review, we summarize biosynthesis, membrane transport, and physiological functions of UA. Then, we discuss the pathological involvement of hyperuricemia and hypouricemia as well as the underlying mechanisms by which UA at abnormal levels regulates the onset and progression of diseases. Finally, pharmacological strategies for urate-lowering therapy (ULT) are introduced, and current challenges in UA study and future perspectives are also described.

Effect of uric acid reduction on chronic kidney disease. Systematic review and meta-analysis

Accumulating evidence suggests that hyperuricemia is a pathological factor in the development and progression of chronic kidney disease. However, the potential benefit afforded by the control of uric acid (UA) is controversial. Individual studies show discrepant results, and most existing meta-analysis, especially those including the larger number of studies, lack a placebo or control group as they aim to compare efficacy between drugs. On these grounds, we performed a me-ta-analysis restricted to studies including the action of any anti-gout therapies referenced to a control or placebo arm. This approach allows for a clearer association between UA reduction and renal effect. Of the twenty-nine papers included, most used allopurinol and febuxostat and, therefore, solid conclusions could only be obtained for these drugs. Both were very effective in reducing UA, but only allopurinol was able to significantly improve glomerular filtration rate (GFR), although not in a dose-dependent manner. These results raised doubts as to whether it is the hypouricemic effect of anti-gout drugs, or a pleiotropic effect, what provides protection of kidney function. Accordingly, in a correlation study that we next performed between UA reduction and GFR improvement, no association was found, which suggests that additional mechanisms may be involved. Of note, most trials show large inter-individual response variability, probably because they included patients with heterogeneous phenotypes and pathological characteristics, including different stages of CKD and comorbidities. This highlights the need to sub classify the effect of UA-lowering therapies according to the pathological scenario, in order to identify those CKD patients that may benefit most from them. Systematic Review Registration: CRD42022306646 https://www.crd.york.ac.uk/prospero/.

Impact of Hyperuricemia and Urate-Lowering Agents on Cardiovascular Diseases

The association between hyperuricemia and cardiovascular diseases has been studied for many years. Research has shown a link between high uric acid levels and increased risk of including coronary artery disease hypertension and other cardiovascular conditions. Urate-lowering therapy, particularly with xanthine oxidase inhibitors like allopurinol, has shown promising results in reducing blood pressure in individuals with hyperuricemia and hypertension. Clinical trials and studies have demonstrated significant reductions in both systolic and diastolic blood pressure with urate-lowering treatment. Urate-lowering treatment has shown a favorable effect on reducing systolic blood pressure and major adverse cardiovascular events in patients with previous cardiovascular disease. In terms of cardiovascular safety, clinical trials have indicated that xanthine oxidase inhibitors such as febuxostat are non-inferior to allopurinol and do not increase the risk of death or serious adverse events. Overall, these findings highlight the importance of managing hyperuricemia and utilizing urate-lowering therapy to mitigate the adverse cardiovascular effects associated with elevated uric acid levels.

Dotinurad restores exacerbated kidney dysfunction in hyperuricemic patients with chronic kidney disease

BACKGROUND

In this study, we aimed to clarify the beneficial effects of urate-lowering treatment with the novel agent dotinurad on renal function in patients with chronic kidney disease (CKD) and hyperuricemia (HUA).

METHODS

Thirty-five patients with CKD (mean age 65.4 ± 14.8 years, 23 men) diagnosed with HUA were recruited. Changes in eGFR before and after dotinurad administration were assessed. Patients first underwent a 3-month observation period and then 3 months treatment with dotinurad.

RESULTS

During the observation period, mean eGFR (mL/min/1.73 m2) declined significantly. The baseline eGFR was 31.8 ± 16.4 and the serum urate level (sUA, mg/dL) was 8.1 ± 1.7. During the treatment period, eGFR recovered to 36.5 ± 17.5 and sUA decreased to 6.7 ± 1.0. The increase in eGFR after dotinurad administration was correlated with a decrease in sUA (R = 0.375, p = 0.0263).

CONCLUSION

Dotinurad administration to patients with CKD and HUA appears to be beneficial in restoring kidney function. Dotinurad may represent a potential medication for the prevention of kidney function decline caused by HUA.

Cardiovascular Safety of Febuxostat in Patients With Gout or Hyperuricemia: A Systematic Review of Randomized Controlled Trials

INTRODUCTION

To this date, a causal relationship between febuxostat and cardiovascular disease remains controversial as comparison between trials can be challenging and may lead to misleading conclusions, especially when facing heterogeneous cardiovascular outcomes. We aimed to compare the cardiovascular outcomes in the most pertinent trials of febuxostat compared with controls.

METHODS

We searched electronic databases using a PICOS-style approach search strategy of randomized controlled trials (RCTs) on cardiovascular outcomes of febuxostat in patients with gout or hyperuricemia. We conducted a quality and risk of bias assessment of the included clinical trials. The definition of major adverse cardiovascular event as well as all reported cardiovascular outcomes were retrieved from every involved trial.

RESULTS

Of the 1173 records identified from all sources, 20 RCTs were included in the analysis. The mean duration of follow-up was 69.7 ± 81.5 weeks, and febuxostat dose ranged from 10 to 240 mg with 80 mg being the most commonly used dosage. Overall, the quality of evidence deriving from all RCTs showed concerns in most studies (65%). Major adverse cardiovascular event was defined in 7 of the 20 RCTs (35%), and cardiovascular outcome reporting was very heterogeneous. Overall, the data of cardiovascular safety of febuxostat were reassuring.

CONCLUSIONS

Our systematic review showed high level of concerns in quality assessment domains as well heterogeneous cardiovascular outcomes across included studies. Cardiovascular outcomes in the majority of White males with gout treated with febuxostat were reassuring when compared with allopurinol. Further studies are needed to draw conclusions in patients with severe cardiovascular disease.

Urate-Lowering Drugs and Muscle Injury: A Systematic Review and Network Meta-Analysis

Several urate-lowering drugs have been linked to muscle injury. This study investigated the association of oral urate-lowering drugs with the risk of muscle injury by performing a network meta-analysis of randomized and non-randomized controlled trials. A systematic search of MEDLINE, via PubMed, the ClinicalTrials.gov website, and the Cochrane Central Register of Controlled Trials was conducted to identify relevant studies with a primary outcome of "all muscle injuries." A random-effects model was used to perform a frequentist network meta-analysis to estimate whether there was significant heterogeneity among the studies. In total, 32 studies including 28,327 participants with 2694 (9.5%) "all muscle injuries" were assessed, and the overall risk of bias was judged to be low to moderate. No statistically significant differences were found between placebo and 6 urate-lowering therapies: allopurinol (risk ratio, RR, 1.05; 95% confidence interval, 95%CI, 0.63-1.73), febuxostat (RR 1.10, 95%CI 0.71-1.70), lesinurad (RR 7.00, 95%CI 0.31-160.36), lesinurad concomitant with allopurinol (RR 0.85, 95%CI 0.34-2.11), lesinurad concomitant with febuxostat (RR 1.97, 95%CI 0.55-7.03), and topiroxostat (RR 0.99, 95%CI 0.37-2.65). The findings suggest that there is little need to consider the risk of muscle injury when using urate-lowering drugs in the clinical setting.

Efficacy of dotinurad in patients with severe renal dysfunction

BACKGROUND

Although hyperuricemia is associated with the progression of chronic kidney disease (CKD), a reduction in CKD progression by uric acid (UA)-lowering therapy has been controversial. Recently, dotinurad, a uricosuric drug with selective urate reabsorption inhibitory properties, has been developed. However, its efficacy in lowering serum UA levels and its effects on renal function in patients with severe renal dysfunction are unclear. Thus, this study aimed to determine the effects of dotinurad on renal function in patients with severe renal dysfunction.

METHODS

Data from 53 outpatients with hyperuricemia who newly received dotinurad between December 2020 and October 2022 were retrospectively analyzed. The mean baseline estimated glomerular filtration rate (eGFR) was 38.7 ± 17.0 mL/min/1.73 m2. The patients were divided into three groups based on their baseline eGFR: eGFR < 30 (n = 17), 30 ≤ eGFR < 45 (n = 17), and eGFR ≥ 45 (n = 19).

RESULTS

The mean follow-up period was 9.8 ± 4.5 (range, 3-21) months. Serum UA levels significantly decreased in all groups. Although eGFR did not significantly change in patients with 30 ≤ eGFR < 45 and eGFR ≥ 45 (P = 0.918 and P = 0.535, respectively), it improved significantly in patients with eGFR < 30 (P = 0.032). The proportion of patients with improved eGFR was significantly higher in patients with eGFR < 30 (P = 0.038) than in patients with 30 ≤ eGFR < 45 and eGFR ≥ 45. In the multivariate logistic regression analysis, baseline eGFR < 30 and achieving a serum UA level of ≤ 6.0 mg/dL were significantly associated with improved eGFR (P = 0.033 and P = 0.015, respectively).

CONCLUSIONS

Dotinurad may have UA-lowering effects and the potential to improve kidney function in patients with severe renal dysfunction.

The Uricosuric Effect of SGLT2 Inhibitors Is Maintained in the Long Term in Patients with Chronic Kidney Disease and Type 2 Diabetes Mellitus

(1) Background: Sodium-glucose co-transporter 2 inhibitors (SGLT2is) increase uric acid excretion. The intensity of uricosuria is linked to glycosuria. (2) Methods: We aim to analyze the effect of SGLT2 inhibitors on urinary fractional excretion (FE) of uric acid and glucose in patients with type 2 diabetes mellitus (T2DM) and chronic kidney disease (CKD) in a single-center retrospective study with patients with T2DM and CKD who started on treatment with SGLT2is. Patients on renal replacement therapy or with glucagon-like peptide-1 (GLP1) analogs were excluded. Subgroup analysis was performed according to the estimated glomerular filtration rate (eGFR), the SGLT2i molecule, the main comorbidities, and concomitant treatment. As a secondary objective, the study analyzed the effect of SGLT2 inhibitors on uricemia levels. (3) Results: Seventy-three patients were analyzed, with a mean follow-up of 1.2 years. Uric acid and glucose FE significantly increased after the initiation of SGLT2is. This increase remained stable during the follow-up without differences among eGFR groups. No significant reduction in uricemia was observed. However, a trend towards a decrease was observed. (4) Conclusion: The use of SGLT2is in patients with CKD and T2DM is associated with an increase in uric acid FE, which maintains stability irrespective of glomerular filtration loss at least during 24 months of follow-up.

Consensus statement on the management of patients with asymptomatic hyperuricemia in general medical practice

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Effects of uric acid-lowering therapy (ULT) on renal outcomes in CKD patients with asymptomatic hyperuricemia: a systematic review and meta-analysis

BACKGROUND

It is well known that asymptomatic hyperuricemia and gout play an important role in patients with chronic kidney disease (CKD). However, the effect of uric acid-lowering therapy (ULT) on the prognosis of CKD patients with asymptomatic hyperuricemia remains controversial. Therefore, we aim to investigate the influence of ULT on renal outcomes in these patients.

METHODS

Comprehensive searches were conducted in PubMed, EMBASE, China National Knowledge Internet (CNKI), and the Cochrane Library, up until January 2024. We included randomized controlled trials (RCTs) that evaluated the effects of ULT on renal outcomes in CKD patients with asymptomatic hyperuricemia.

RESULTS

A total of 17 studies were included in the meta-analysis. Compared with placebo or no treatment, ULT preserved the loss of estimated glomerular filtrating rate (eGFR) (Weighted mean difference [WMD] and its 95% confidence intercal(CI): 2.07 [0.15,3.98] mL/min/1.73m2) at long-term subgroup. At the same time, short-term subgroup also proved the preserved loss of eGFR (WMD 5.74[2.09, 9.39] mL/min/1.73m2). Compared with placebo or no treatment, ULT also reduced the increase in serum creatinine (Scr) at short-term (WMD -44.48[-84.03,-4.92]μmol/L) subgroup and long-term (WMD -46.13[-65.64,-26.62]μmol/L) subgroup. ULT was associated with lower incidence of the events of doubling of Scr without dialysis (relative risk (RR) 0.32 [0.21, 0.49], p < 0.001). However, no difference was found for lower incidence of acute kidney injury (AKI) (p = 0.943).

CONCLUSIONS

According to our study, ULT is beneficial for slowing CKD progression both in short to long-term follow-ups. Additionally, in patients younger than 60 years old, the protective effect of ULT on renal outcome is more pronounced. However, it showed no significant difference in the incidence of AKI. These findings underscore the importance of considering ULT in clinical strategies for CKD patients with asymptomatic hyperuricemia.