Renoprotective effects of febuxostat compared with allopurinol in patients with hyperuricemia: A systematic review and meta-analysis

Efficacy and Safety of Allopurinol on Chronic Kidney Disease Progression: A Systematic Review and Meta-Analysis

OBJECTIVE

Hyperuricemia is associated with the progression of chronic kidney disease (CKD). Whether urate-lowering treatment with allopurinol can delay disease progression remains controversial.

METHODS

Relevant databases were searched. Randomized clinical trials comparing the efficacy and -safety of allopurinol in patients with CKD were selected. The primary outcomes were changes in serum uric acid concentration and estimated glomerular filtration rate (eGFR). Random-effects modeling was used to -calculate the standard mean difference (SMD) with 95% CIs.

RESULTS

Four trials enrolling 698 participants were included. All were 2-arm parallel trials with a mean duration follow-up of 22.5 months. Congenital anomalies of the kidney and urinary tract were the most common cause of CKD in children, whereas diabetes was the leading cause of CKD in adults. Allopurinol significantly increased the eGFR compared with control groups (SMD, 2.04; 95% CI, 0.60-3.49; p = 0.005; I2 = 98.23%). Allopurinol led to a significant decrease in serum uric acid concentration compared with the control group (SMD, -5.16; 95% CI, -8.31 to -2.01; p = 0.001; I2 = 98.80%). No significant difference in adverse effects was identified between treatment and control groups.

CONCLUSIONS

Allopurinol treatment in patients with CKD and hyperuricemia slows the decline in eGFR as compared with placebo, without risk of increased adverse effects.

Combination Treatment with Verinurad and Allopurinol in CKD: A Randomized Placebo and Active Controlled Trial

Key Points

The SAPPHIRE trial was designed to assess albuminuria-lowering effects of the urate transporter 1 inhibitor verinurad combined with allopurinol in patients with CKD. Verinurad 3, 7.5, and 12 mg in combination with allopurinol 300 mg did not reduce albuminuria during 34 weeks treatment compared with allopurinol alone or placebo. Verinurad/allopurinol combination dose-dependently reduced serum urate concentrations compared with placebo.

Background

Hyperuricemia is associated with elevated risks of cardiovascular and chronic kidney disease (CKD). Since inhibition of urate transporter 1 has been suggested to be potentially nephroprotective, we performed a phase 2b study to assess albuminuria-lowering effects of the urate transporter 1 inhibitor verinurad combined with the xanthine oxidase inhibitor allopurinol in patients with CKD and hyperuricemia.

Methods

In this randomized placebo and active controlled trial, we enrolled participants with serum urate concentrations ≥6.0 mg/dl, eGFR ≥25 ml/min per 1.73 m2, and a urinary albumin-creatinine ratio (UACR) 30–5000 mg/g to one of five treatment arms: placebo, placebo+allopurinol 300 mg/day, verinurad 3 mg+allopurinol 300 mg/day, verinurad 7.5 mg+allopurinol 300 mg/day, or verinurad 12 mg+allopurinol 300 mg/day in a 1:1:1:1:1 ratio. The primary end point was the change in UACR from baseline to 34 weeks. Secondary end points were changes from baseline in UACR at week 60 and changes in serum urate and eGFR at weeks 34 and 60.

Results

Between August 2019 and November 2021, 861 adults with CKD (mean age 65 years, 33.0% female, mean eGFR 48 ml/min per 1.73 m2, median UACR 217 mg/g) were enrolled. At 34 weeks, the geometric mean percentage change in UACR from baseline did not differ among treatment groups (16.7%, 95% confidence interval [CI], −0.6 to 37.1 in the 3 mg group, 15.0% [95% CI, −1.85 to 34.6] in the 7.5 mg group, 14.0% [95% CI, −3.4 to 34.4] in the 12 mg group versus 9.9% [95% CI, −6.6 to 29.4] in the allopurinol group, and 37.3% [95% CI, 16.6 to 61.8] in the placebo group). UACR and eGFR change from baseline did not differ among treatment groups after 60 weeks. Verinurad/allopurinol combination dose-dependently reduced serum urate concentrations compared with placebo. The proportion of patients with adverse events and serious adverse events was balanced among treatment groups.

Conclusions

Verinurad in combination with allopurinol did not decrease UACR or eGFR decline, but further reduced serum urate compared with allopurinol alone or placebo.

Clinical Trial registry name and registration number:

SAPPHIRE Trial registration number, NCT03990363 .

A Possible Therapeutic Application of the Selective Inhibitor of Urate Transporter 1, Dotinurad, for Metabolic Syndrome, Chronic Kidney Disease, and Cardiovascular Disease

The reabsorption of uric acid (UA) is mainly mediated by urate transporter 1 (URAT1) and glucose transporter 9 (GLUT9) in the kidneys. Dotinurad inhibits URAT1 but does not inhibit other UA transporters, such as GLUT9, ATP-binding cassette transporter G2 (ABCG2), and organic anion transporter 1/3 (OAT1/3). We found that dotinurad ameliorated the metabolic parameters and renal function in hyperuricemic patients. We consider the significance of the highly selective inhibition of URAT1 by dotinurad for metabolic syndrome, chronic kidney disease (CKD), and cardiovascular disease (CVD). The selective inhibition of URAT1 by dotinurad increases urinary UA in the proximal tubules, and this un-reabsorbed UA may compete with urinary glucose for GLUT9, reducing glucose reabsorption. The inhibition by dotinurad of UA entry via URAT1 into the liver and adipose tissues increased energy expenditure and decreased lipid synthesis and inflammation in rats. Such effects may improve metabolic parameters. CKD patients accumulate uremic toxins, including indoxyl sulfate (IS), in the body. ABCG2 regulates the renal and intestinal excretion of IS, which strongly affects CKD. OAT1/3 inhibitors suppress IS uptake into the kidneys, thereby increasing plasma IS, which produces oxidative stress and induces vascular endothelial dysfunction in CKD patients. The highly selective inhibition of URAT1 by dotinurad may be beneficial for metabolic syndrome, CKD, and CVD.

Effectiveness and safety of different doses of febuxostat compared with allopurinol in the treatment of hyperuricemia: a meta-analysis of randomized controlled trials

BACKGROUND

The prevalence of hyperuricemia has increased steadily with the continuous improvement of living standards. Some studies have reported the clinical effectiveness and safety of different doses of febuxostat in comparison with allopurinol in hyperuricemia treatment, but the sample sizes of the studies have been small, and the results have been inconsistent. We designed this meta-analysis to evaluate the effectiveness and safety of different doses of febuxostat compared with allopurinol in the treatment of hyperuricemia.

METHODS

The Cochrane Library, Embase, PubMed, Web of Science and ClinicalTrials.gov databases were searched to identify randomized controlled trials (RCTs) comparing the use of febuxostat and allopurinol for the treatment of hyperuricemia. The effectiveness and safety of different doses of febuxostat and allopurinol in treating hyperuricemia were assessed using meta-analysis.

RESULTS

A total of 11 randomized controlled trials were included in the meta-analysis. The results of the meta-analysis showed that the percentage of patients achieving serum uric acid levels of 6.0 mg/dL or less was higher among patients taking febuxostat (80 mg/d) than among patients taking allopurinol (200-300 mg/d) [RR = 1.79, 95% CI (1.55, 2.08), P < 0.00001]. However, there was no statistically significant difference in the percentage of patients achieving serum uric acid levels of 6.0 mg/dL or less between febuxostat (40 mg/d) and allopurinol (200-300 mg/d) [RR = 1.10, 95% CI (0.93, 1.31), P = 0.25]. There was also no statistically significant difference in the incidence of gout between the febuxostat (40 mg/d) and allopurinol (200-300 mg/d) [RR = 0.97, 95% CI (0.64, 1.49), P = 0.91] or between the febuxostat (80 mg/d) and allopurinol (200-300 mg/d) [RR = 1.13, 95% CI (0.81, 1.58), P = 0.48].No significant difference in the incidence of major adverse reactions as observed between the febuxostat (40 mg/d) and allopurinol (200-300 mg/d) [RR = 1.16; 95% CI (0.43, 3.16), P = 0.77] or between the febuxostat (80 mg/d) and allopurinol (200-300 mg/d) [RR = 1.06; 95% CI (0.79, 1.42), P = 0.70]. The incidence of adverse cardiovascular events did not differ significantly between the febuxostat (40 mg/d) and allopurinol (200-300 mg/d) [RR = 1.30; 95% CI (0.57, 2.95), P = 0.53] or between the febuxostat (80 mg/d) and allopurinol (200-300 mg/d) [RR = 1.79; 95% CI (0.74, 4.32), P = 0.20].

CONCLUSIONS

Febuxostat (80 mg/d) was associated with a higher percentage of patients achieving serum uric acid levels of 6.0 mg/dL or less than allopurinol (200-300 mg/d), however, febuxostat (80 mg/d) did not exhibit better efficacy in reducing the incidence of gout. More attention should be devoted to the adverse reactions caused by an increase in febuxostat doses.

Celebrating Versatility: Febuxostat's Multifaceted Therapeutic Application

Febuxostat, initially developed as a xanthine oxidase inhibitor to address hyperuricemia in gout patients, has evolved into a versatile therapeutic agent with multifaceted applications. This review provides a comprehensive overview of febuxostat's mechanism of action, its effectiveness in gout management, its cardiovascular safety profile, renal and hepatic effects, musculoskeletal applications, safety considerations, and emerging research prospects. Febuxostat's primary mechanism involves selective inhibition of xanthine oxidase, resulting in reduced uric acid production. Its pharmacokinetics require personalized dosing strategies based on individual characteristics. In gout management, febuxostat offers a compelling alternative, effectively lowering uric acid levels, relieving symptoms, and supporting long-term control, especially for patients intolerant to allopurinol. Recent studies have demonstrated its cardiovascular safety, and it exhibits minimal hepatotoxicity, making it suitable for those with liver comorbidities. Febuxostat's potential nephroprotective effects and kidney stone prevention properties are noteworthy, particularly for gout patients with renal concerns. Beyond gout, its anti-inflammatory properties hint at applications in musculoskeletal conditions and a broader spectrum of clinical contexts, including metabolic syndrome. Emerging research explores febuxostat's roles in cardiovascular health, neurological disorders, rheumatoid arthritis, and cancer therapy, driven by its anti-inflammatory and antioxidative properties. Future directions include personalized medicine, combination therapies, mechanistic insights, and ongoing long-term safety monitoring, collectively illuminating the promising landscape of febuxostat's multifaceted therapeutic potential.

Febuxostat alleviates Arsenic Trioxide-Induced renal injury in Rats: Insights on the crosstalk between NLRP3/TLR4, Sirt-1/NF-κB/TGF-β signaling Pathways, and miR-23b-3p, miR-181a-5b expression

Febuxostat (FBX), a xanthine oxidase inhibitor, is known to improve renal function and can show promise as a therapeutic agent for preventing drug-induced nephrotoxicity. This study aimed to explore the protective effect of FBX in preventing renal damage caused by arsenic trioxide (ATO) toxicity and uncover the underlying mechanisms. The researchers examined how FBX (10 mg/kg, orally) affected ATO-induced kidney injury (5 mg/kg, intraperitoneally) in rats. Kidney function and toxicity parameters in serum and oxidative stress biomarkers and inflammatory cytokine levels in renal tissue were measured. H&E staining was used to detect histopathological changes in the kidney. Network the molecular mechanisms of FBX in improving kidney injury were investigated using Western blotting and PCR techniques. The findings showed that FBX improved kidney function by inhibiting the pathological changes seen in H&E staining, decreasing levels of probed kidney function and toxicity measures in serum and tissue, and exhibiting antioxidant and anti-inflammatory effects. FBX decreased MDA, MPO, TNF-α, IL-1β, IL-6, COX-II, and NADPH oxidase levels, while increased GSH, GPx, SOD, and IL-10 levels. FBX also reduced the expression of NLRP3, ASC, TLR4, and micro-RNA 181a-5b while increased the expression of IKBα, Sirt-1, and micro-RNA 23b-3p, according to Western blotting and PCR results. In conclusion, FBX can play a vital role in reducing kidney injury in cases of ATO-induced nephrotoxicity, though more clinical research needs to be conducted.

Korean guidelines for the management of gout

Gout is the most common form of arthritis, with the prevalence increasing worldwide. The present treatment guidelines provide recommendations for the appropriate treatment of acute gout, management during the inter-critical period, and prevention of chronic complications. The guidelines were developed based on evidence-based medicine and draft recommendations finalized after expert consensus. These guidelines are designed to provide clinicians with clinical evidence to enable efficient treatment of gout.

Korean guidelines for the management of gout

Gout is the most common form of arthritis, with the prevalence increasing worldwide. The present treatment guidelines provide recommendations for the appropriate treatment of acute gout, management during the inter-critical period, and prevention of chronic complications. The guidelines were developed based on evidence-based medicine and draft recommendations finalized after expert consensus. These guidelines are designed to provide clinicians with clinical evidence to enable efficient treatment of gout.

Therapeutics in rheumatology and the kidney

The field of rheumatology has advanced significantly in recent years to provide rheumatologists with an extensive array of medications to combat rheumatic joint conditions. In contrast to an older era, when NSAIDs and other nephrotoxic agents were the mainstay of treatment, modern DMARDs vary considerably in their nephrotoxic potential and their use is not always precluded in populations with pre-existing chronic kidney disease (CKD). This review will explore in detail the safety and efficacy profiles of medications used to treat rheumatologic disease, specifically in the setting of CKD. Specifically, we discuss both traditional agents used, i.e. NSAIDs, CSs and conventional synthetic DMARDs, as well as novel biologic DMARDs and targeted synthetic DMARDs. Anti-gout prescribing in CKD is also reviewed. We aim to provide practical guidance to rheumatologists, nephrologists and general physicians when prescribing these medications in the setting of CKD.

Ameliorative Effect of Mannuronate Oligosaccharides on Hyperuricemic Mice via Promoting Uric Acid Excretion and Modulating Gut Microbiota

Mannuronate oligosaccharide (MOS) is α-D-mannuronic acid polymer with 1,4-glycosidic linkages that possesses beneficial biological properties. The aim of this study was to investigate the hypouricemic effect of MOS in hyperuricemic mice and demonstrate the possible protective mechanisms involved. In this research, 200 mg/kg/day of MOS was orally administered to hyperuricemic mice for four weeks. The results showed that the MOS treatment significantly reduced the serum uric acid (SUA) level from 176.4 ± 7.9 μmol/L to 135.7 ± 10.9 μmol/L (p < 0.05). MOS alleviated the inflammatory response in the kidney. Moreover, MOS promoted uric acid excretion by regulating the protein levels of renal GLUT9, URAT1 and intestinal GLUT9, ABCG2. MOS modulated the gut microbiota in hyperuricemic mice and decreased the levels of Tyzzerella. In addition, research using antibiotic-induced pseudo-sterile mice demonstrated that the gut microbiota played a crucial role in reducing elevated serum uric acid of MOS in mice. In conclusion, MOS may be a potential candidate for alleviating HUA symptoms and regulating gut microbiota.

The effect of trajectory of serum uric acid on survival and renal outcomes in patients with stage 3 chronic kidney disease

Uric acid (UA) is associated with renal disease and patient survival, but the causal associations remain unclear. Also, the longitudinal UA control (trajectory) is not well understood. We enrolled 808 subjects diagnosed with stage 3 chronic kidney disease from 2007 to 2017. We plotted the mean UA over a period of 6 months with a minimum requirement of 3 samples of UA. From the sampled points, we generated an interpolated line for each patient by joining mean values of UA levels over time. Using lines from all patients, we classified them into 3 groups of trajectories (low, medium, and high) through group-based trajectory modeling, and then we further separated them into either treatment or nontreatment subgroups. Due to multiple comparisons, we performed post hoc analysis by Bonferroni adjustment. Using univariate competing-risks regression, we calculated the competing risk analysis with subdistribution hazard ratio of possible confounders. All of the 6 trajectories appeared showed a gradual decline in function over time without any of the curves crossing over one another. For all-cause mortality risk, none of the variables (including age, gender, coronary arterial disease, cerebrovascular disease, diabetes mellitus, renin-angiotensin-aldosterone system inhibitors, trajectories of UA, and treatment of UA) were statistically significant. All 6 trajectories appeared as steady curves without crossovers among them over the entire period of follow-up. Patients with diabetes mellitus were statistically more likely to undergo dialysis. The only trend was seen in the on-treatment trajectories, which showed lower risks for dialysis compared to their nontreatment trajectories. There was no effect of UA control on survival. Initial treatment of UA is crucially important for UA control. However, the long-term effects on patients and renal survival appeared to be minor and without statistical significance.

Urate-lowering efficacy and renal safety of febuxostat in patients with hyperuricemia and stage 4-5 chronic kidney disease not yet on dialysis: A meta-analysis of observational studies

OBJECTIVE

The efficacy and safety of febuxostat in patients with stage 4-5 chronic kidney disease (CKD) remains unclear. We evaluated the urate-lowering efficacy and renal safety of febuxostat in patients with stage 4-5 CKD not yet on dialysis, through a meta-analysis of observational studies.

METHODS

We performed a systematic search in PubMed, Ovid MEDLINE, Embase, and the Cochrane Library databases for observational studies of patients with advanced CKD starting febuxostat. Articles describing changes in serum urate levels and/or renal function assessed by the estimated glomerular filtration rate (eGFR) were included.

RESULTS

Among 148 retrieved studies, five relevant observational studies with 327 patients were included in the meta-analysis. Febuxostat was administered daily at 10-120 mg for 3-12 months. Serum urate reduced in response to febuxostat (weighted mean difference, -1.85 mg/dL; 95% CI, -2.04--1.67 mg/dL; I²; 0%). Three studies involving 145 patients included eGFR assessments. Renal function, assessed through the eGFR, did not change after febuxostat use (weighted mean difference, 0.11 mL/min/1.73m²; 95% CI, -0.25-0.47 mL/min/1.73m²; I²; 45%).

CONCLUSION

Overall, febuxostat has acceptable urate-lowering efficacy and renal safety in patients with hyperuricemia and stage 4-5 CKD who are not yet on dialysis.

Efficacy and safety of urate-lowering agents in asymptomatic hyperuricemia: systematic review and network meta-analysis of randomized controlled trials

BACKGROUND

Asymptomatic hyperuricemia was found to be associated with increased cardiovascular disease risk but the potential benefits of urate-lowering therapy (ULT) remain controversial. We conducted a systematic review and network meta-analysis (NMA) with frequentist model to estimate the efficacy and safety of ULT in asymptomatic hyperuricemia.

METHODS

MEDLINE, Embase, and Scopus were searched without language restrictions. Randomized controlled trials (RCT) of adults with asymptomatic hyperuricemia were eligible if they compared any pair of ULTs (i.e., allopurinol, febuxostat, probenecid, benzbromarone, sulfinpyrazone, rasburicase, lesinurad, and topiroxostat) and placebo or no ULT, and had outcomes of interest, including composite renal events, major adverse cardiovascular events, serum urate levels, estimated glomerular filtration rate (eGFR), systolic blood pressure, and adverse events.

RESULTS

NMA with frequentist approach was applied to estimate relative treatment effects, i.e., risk ratio (RR) and mean difference (MD). A total of 23 RCTs were eligible. NMA identified beneficial effects of ULT on composite renal events and eGFR but not for other outcomes. Allopurinol and febuxostat had significantly lower composite renal events than placebo (RR 0.39, 95% confidence interval [CI] 0.23 to 0.66, and RR 0.68, 95% CI 0.46 to 0.99, respectively). Both treatments also resulted in significantly higher eGFR than placebo (MD 3.69 ml/min/1.73 m², 95% CI 1.31 to 6.08, and MD 2.89 ml/min/1.73 m², 95% CI 0.69 to 5.09, respectively). No evidence of inconsistency was identified.

CONCLUSIONS

Evidence suggests that allopurinol and febuxostat are the ULTs of choice in reducing composite renal events and improving renal function.

TRIAL REGISTRATION

This study was registered with PROSPERO: CRD42019145908. The date of the first registration was 12^th November 2019.

Systematically Exploring the Chemical Ingredients and Absorbed Constituents of Polygonum capitatum in Hyperuricemia Rat Plasma Using UHPLC-Q-Orbitrap HRMS

Polygonum capitatum as an ethnic medicine has been used to treat urinary tract infections, pyelonephritis and urinary calculi. In our previous study, P. capitatum was found to have anti-hyperuricemia effects. Nevertheless, the active constituents of P. capitatum for treating hyperuricemia were still unclear. In this study, an ultra-high-performance liquid chromatography coupled to quadrupole/orbitrap high-resolution mass spectrometry (UHPLC-Q-Orbitrap HRMS) was used to comprehensively detect the chemical ingredients of P. capitatum and its absorbed constituents in the plasma of hyperuricemia rats for the first time. Xcalibur 3.0 and Compound Discoverer 2.0 software coupled to mzCloud and ChemSpider databases were utilized for qualitative analysis. A total of 114 chemical components including phenolics, flavonoids, tannins, phenylpropanoids, amino acids, amides and others were identified or tentatively characterized based on the exact mass, retention time and structural information. Compared to the previous P. capitatum study, an additional 66 different components were detected. Moreover, 68 related xenobiotics including 16 prototype components and 52 metabolites were found in the plasma of hyperuricemia rats. The metabolic pathways included ring fission, hydrolysis, decarboxylation, dehydroxylation, methylation, glucuronidation and sulfation. This work may provide important information for further investigation on the active constituents of P. capitatum and their action mechanisms for anti-hyperuricemia effects.

Superior effect of allopurinol compared to febuxostat on the retardation of chronic kidney disease progression

BACKGROUND

Although hyperuricemia is associated with chronic kidney disease, whether and how it should be managed for renoprotection remains debatable. Thus, we investigated whether allopurinol and febuxostat, the most frequently used urate-lowering treatments, have differential renoprotective effects on chronic kidney disease.

METHODS

Incident users of allopurinol and febuxostat were identified from two tertiary referral centers. One-to-one propensity score matching between the allopurinol and febuxostat groups was performed. Participants were followed up until the occurrence of clinical outcomes, urate-lowering agent discontinuation, mortality, or the end of the study period, whichever occurred first. The primary outcomes were a 30% decline in estimated glomerular filtration rate (eGFR) and end-stage renal disease. Differential trends of eGFR decline were estimated using a linear mixed-effects model.

RESULTS

Each group included 654 participants. Baseline eGFRs were 40.1 [26.6-57.3] and 39.1 [27.9-58.3] mL/min/1.73 m2 in the allopurinol and febuxostat group, respectively. Adjusted least square mean change in serum urate was -1.58 mg/dL [95% confidence interval (CI), -1.78 to -1.38] and -2.69 mg/dL (95% CI, -2.89 to -2.49) in the allopurinol and febuxostat groups, respectively. Despite lower serum urate levels, febuxostat was significantly more associated with a 30% decline in eGFR (hazard ratio 1.26; 95% CI 1.03-1.54) and end-stage renal disease (hazard ratio 1.91, 95% CI 1.42-2.58) than allopurinol. Annual eGFR decline in febuxostat users was estimated to be more rapid than in allopurinol users by 2.14 (standard error 0.71) mL/min/1.73 m2 per year.

CONCLUSIONS

Allopurinol demonstrated attenuation of chronic kidney disease progression and prevention of hypouricemia, compared to febuxostat. Because the treatment can be renoprotective, further studies on its effects on chronic kidney disease are required.

In vitro and in vivo ameliorative effects of polyphenols from purple potato leaves on renal injury and associated inflammation induced by hyperuricemia

In the present study, the ameliorative effects of polyphenols from purple potato leaves (PSPLP) on hyperuricemia were investigated. HPLC-MS analysis showed that PSPLP was mainly composed of caffeoylquinic acid derivatives (84%). PSPLP inhibited the levels of cytokines (IL-1β, IL-6, and TNF-α) in monosodium urate-induced RAW264.7 cells. In vivo, PSPLP significantly inhibited the level of uric acid in hyperuricemia mice from 209.6 to 166.6 μM, and significantly interfered with the activities of xanthine oxidase (XOD) and adenosine deaminase in liver, the activity of XOD decreased from 13.5 to 11.6 U/gprot. PSPLP can decrease serum creatinine level from 105 to 59 μM, and urea nitrogen level from 21.9 to 14.1 mM, which can effectively protect kidney. These results provide a reference for future research and application of PSPLP as a functional food to intervene hyperuricemia and associated inflammation. PRACTICAL APPLICATIONS: This study evaluated the effect of polyphenols from purple potato leaves (PSPLP) on hyperuricemia. The results suggested that PSPLP has an important role in the intervention of hyperuricemia and hyperuricemic-related inflammation or renal injury, and can be used in the application of functional foods. These results provided a basis for further study on the biological activities of polyphenols from purple sweet potato leaves.

Effectiveness of Drug Treatments for Lowering Uric Acid on Renal Function in Patients With Chronic Kidney Disease and Hyperuricemia: A Network Meta-Analysis of Randomized Controlled Trials

Background: Hyperuricemia is very common in patients with chronic kidney disease (CKD); the role of hyperuricemia in the occurrence and progression of kidney disease remains an interesting and unresolved issue for nephrologists, and whether urate-lowering therapy (ULT) is warranted in CKD patients is still in controversy. To summarize and compare the clinical outcomes and adverse events (AEs) of three common ULT drugs, we performed a systematic review and network meta-analysis of randomized clinical trials (RCTs). Method: PubMed, MEDLINE, Clinical Trials.gov, EMBASE, and the Cochrane Central Register of Controlled Trials electronic databases were searched. The network meta-analysis was performed using the "gemtc 0.8-7" and its dependent packages in R software. The primary outcome was the change of renal function and uric acid; creatinine, proteinuria, blood pressure, and adverse events were assessed as the secondary outcomes. Results: 16 RCTs involving 1,943 patients were included in the final network analysis. Febuxostat, allopurinol, and benzbromarone were not found to exert superior effects over placebo upon renoprotective effect. With respect to lowering urate, the three drugs showed to be statistically superior to placebo, while febuxostat could better lower urate than allopurinol (MD: -1.547; 95% CrI: -2.473 to -0.626). It is also indicated that febuxostat was superior to placebo at controlling blood pressure, while no differences were observed when allopurinol and benzbromarone were compared to placebo. These results are stable in subgroup analysis. Conclusion: There is insufficient evidence to support the renoprotective effects of the three urate-lowering agents in CKD patients with hyperuricemia; febuxostat shows a tendency to be superior to allopurinol on lowering the decline of eGFR and increment of proteinturia, but the difference does not reach a statistical significance. Regarding its urate-lowering effect, febuxostat appears to be a satisfactory alternative to allopurinol and benzbromarone, and can control blood pressure better.

Contentious Issues in Gout Management: The Story so Far

Gout is the most common inflammatory arthritis worldwide. Although gout has been known for antiquity, many challenges still exist in gout management. It is vital to view gout as a chronic disease and not just treat the acute flare. There is a perception of gout as an acute disease requiring treatment only for acute flares. However, to combat the disease, chronic urate-lowering therapy, reducing the serum urate levels to below the saturation threshold of 6.8 mg/dL, and chronic anti-inflammatory prophylaxis, especially during urate-lowering therapy initiation, are needed. In this manuscript, we discuss some of the contentious issues in gout management. These include the timing of urate-lowering therapy initiation, which urate-lowering therapy to chose, should comorbidities influence our treatment, using genetic determinants, and patient perspectives to drive treatment and differences between gout treatment the American College of Physicians and Rheumatology guidelines for gout management: driving care.

Therapeutic Strategies for the Treatment of Chronic Hyperuricemia: An Evidence-Based Update

This article aims to critically review the evidence on the available therapeutic strategies for the treatment of hyperuricemia. For this reason, several papers were reviewed. Xanthine oxidase inhibitors are the safest and most effective uric acid lowering drugs for the management of chronic hyperuricemia, while the efficacy of uricosuric agents is strongly modulated by pharmacogenetics. Emergent drugs (lesinurad, peglotidase) were found to be more effective for the acute management of refractory hyperuricemia, but their use is supported by a relatively small number of clinical trials so that further well-designed clinical research is needed to deepen their efficacy and safety profile.

Clinical Effects of Xanthine Oxidase Inhibitors in Hyperuricemic Patients

This review aims to critically present the available clinical evidence supporting the treatment of chronic hyperuricemia with xanthine oxidase inhibitors. For this reason, the studies published on uric acid (UA)-lowering drugs in the English language from 2000 to August 2019 have been carefully reviewed. The terms "serum uric acid," "xanthine oxidase," "allopurinol," "febuxostat," and "topiroxostat" were incorporated into an electronic search strategy, alone and in combinations, in both MEDLINE (National Library of Medicine, Bethesda, MD) and the Cochrane Register of Controlled Trials (The Cochrane Collaboration, Oxford, UK). Even if new urate-lowering drugs seem of particular efficacy for acute treatment of refractory hyperuricemia, their use is supported by relatively small clinical evidence. On the contrary, large long-term clinical trials have demonstrated that xanthine oxidase inhibitors (XOIs, namely, allopurinol and febuxostat) are effective, safe, and relatively well-tolerated in most of the patients. They have mainly been tested in the elderly, in patients affected by chronic diseases such as heart failure and cancer, and in patients taking a large number of drugs, confirming their safety profile. Recent data also show that they could exert some positive effects on vascular health, renal function, and glucose metabolism. Their cost is also low. In conclusion, XOIs remain the first choice of UA-lowering drug for chronic treatment.

Renoprotection with SGLT2 inhibitors in type 2 diabetes over a spectrum of cardiovascular and renal risk

Approximately half of all patients with type 2 diabetes (T2D) develop a certain degree of renal impairment. In many of them, chronic kidney disease (CKD) progresses over time, eventually leading to end-stage kidney disease (ESKD) requiring dialysis and conveying a substantially increased risk of cardiovascular morbidity and mortality. Even with widespread use of renin-angiotensin system blockers and tight glycemic control, a substantial residual risk of nephropathy progression remains. Recent cardiovascular outcomes trials investigating sodium-glucose cotransporter 2 (SGLT2) inhibitors have suggested that these therapies have renoprotective effects distinct from their glucose-lowering action, including the potential to reduce the rates of ESKD and acute kidney injury. Although patients in most cardiovascular outcomes trials had higher prevalence of existing cardiovascular disease compared with those normally seen in clinical practice, the proportion of patients with renal impairment was similar to that observed in a real-world context. Patient cardiovascular risk profiles did not relevantly impact the renoprotective benefits observed in these studies. Benefits were observed in patients across a spectrum of renal risk, but were evident also in those without renal damage, suggesting a role for SGLT2 inhibition in the prevention of CKD in people with T2D. In addition, recent studies such as CREDENCE and DAPA-CKD offer a greater insight into the renoprotective effects of SGLT2 inhibitors in patients with moderate-to-severe CKD. This review outlines the evidence that SGLT2 inhibitors may prevent the development of CKD and prevent and delay the worsening of CKD in people with T2D at different levels of renal risk.

Comparative effect of allopurinol and febuxostat on long-term renal outcomes in patients with hyperuricemia and chronic kidney disease: a systematic review

Patients with chronic kidney disease (CKD) are more likely to develop hyperuricemia and gout. Allopurinol and febuxostat are the most commonly used urate-lowering therapies with established safety and efficacy in CKD patients. The objective of the systematic review is to assess the long-term renal outcomes of allopurinol compared with febuxostat in patients with hyperuricemia and CKD or kidney transplantation. PubMed MEDLINE, Embase, Web of Science, Scopus, and Cochrane CENTRAL databases were searched from inception to December 2019 using the key terms "allopurinol," "febuxostat," "xanthine oxidase inhibitors," "gout suppressants," "hyperuricemia," "gout," "chronic renal insufficiency," and "kidney transplantation." Studies with follow-up duration ≥ 12 months were included. Risk of bias was assessed using the Cochrane Risk Of Bias In Non-randomized Studies-of Interventions (ROBINS-I) tool. Three retrospective observational studies with follow-up duration ranging from 1 to 5 years were reviewed. Febuxostat patients had a significantly higher estimated glomerular filtration rate, reduced risk for renal disease progression, and reduced serum uric acid levels compared with allopurinol patients. All studies had a serious risk of bias. Febuxostat may be more renoprotective than allopurinol in patients with both hyperuricemia and CKD based on evidence from small long-term retrospective studies with serious risk of bias. More methodologically rigorous studies are needed to determine the clinical applicability of these results.

A Lanosteryl Triterpene (RA-3) Exhibits Antihyperuricemic and Nephroprotective Effects in Rats

Considering the global health threat posed by kidney disease burden, a search for new nephroprotective drugs from our local flora could prove a powerful strategy to respond to this health threat. In this study we investigated the antihyperuricemic and nephroprotective potential of RA-3, a plant-derived lanosteryl triterpene. The antihyperuricemic and nephroprotective effect of RA-3 was investigated using the adenine and gentamicin induced hyperuricemic and nephrotoxicity rat model. Following the induction of hyperuricemia and nephrotoxicity, the experimental model rats (Sprague Dawley) were orally administered with RA-3 at 50 and 100 mg/kg body weight, respectively, daily for 14 days. Treatment of the experimental rats with RA-3, especially at 100 mg/kg, effectively lowered the serum renal dysfunction (blood urea nitrogen and creatinine) and hyperuricemic (uric acid and xanthine oxidase) biomarkers. These were accompanied by increased antioxidant status with decrease in malondialdehyde content. A much improved histomorphological structure of the kidney tissues was also observed in the triterpene treated groups when compared to the model control group. It is evident that RA-3 possesses the antihyperuricemic and nephroprotective properties, which could be vital for prevention and amelioration of kidney disease.

A treat-to-target approach for gout confers renoprotective effect in patients with chronic kidney disease stage 3

The aim of this study was to assess changes in the estimated glomerular filtration rate (eGFR) in gouty patients with chronic kidney disease (CKD) using a "treat-to-target" (T2T) approach in gout. This multicenter observational retrospective study included patients diagnosed with gout and CKD stage 3 taking xanthine oxidase inhibitors (XOIs) (allopurinol or febuxostat) for at least 12 months. All patients were treated using a T2T strategy according to national gout guidelines to achieve the target levels of serum uric acid (sUA; < 5-6 mg/dl) within 6 months of the first visit. The primary outcome was to assess changes in eGFR. The effects of independent variables were analyzed over eGFR in a linear mixed-effects (LME) model. Fifty patients with gout and CKD stage 3 treated with XOIs with a T2T strategy for 12 months were included. Eighty-two percent of the patients achieved the sUA target during the study period. The improvement seen in eGFR was higher during the first 6 months, showing a median increase of 7.54 ml/min/m² (SE = 1.25) and trending towards stability over 12 months. For every 1 mg/dl of decrease in sUA, an improvement of 1.5 ml/min/m² in eGFR was observed (coefficient ± SE: - 1.58 ± 0.26) (p < 0.001) with no differences between type and dosage of XOIs treatment, colchicine administration, age, sex, and smoking status. A reduction in sUA levels using a T2T approach with XOIs at an optimal dose is possible and could help conserve and improve renal function in gouty patients with CKD stage 3.

Management of asymptomatic hyperuricemia: Integrated Diabetes & Endocrine Academy (IDEA) consensus statement

AIM

The definition and management of asymptomatic hyperuricemia has been an area of controversy for many decades. Debate persists regarding the benefit of treating all cases of asymptomatic hyperuricemia and hence, unsurprisingly there are no clear clinical practice guidelines from our country.

PARTICIPANTS

Ten members consisting of eminent physicians, endocrinologists, nephrologist and a rheumatologist were selected by the Integrated Diabetes & Endocrine Academy (IDEA) for a closed meeting with the aim to come to a consensus.

EVIDENCE

A literature search was performed using PubMed and Cochrane library following which published articles in indexed peer review journals were selected.

CONSENSUS PROCESS

Each participant voiced their opinion after reviewing the available data and a consensus was reached after three meetings by voting.

CONCLUSION

Recommendations were made on important areas such as definition, investigation and management of asymptomatic hyperuricemia.

Acute kidney injury associated with febuxostat and allopurinol: a post-marketing study

BACKGROUND

For patients with recurrent flares of gout, tophi, urate crystal arthropathy, and renal stones, urate-lowering therapies (ULTs, including allopurinol and febuxostat) are the first-line treatment. Due to the widespread use of these ULTs (especially in patients with impaired renal function), assessment of the associated renal risk is essential. Accordingly, we performed a disproportionality analysis of reported cases of acute renal failure (ARF) associated with allopurinol and febuxostat.

METHODS

We carried out a case/non-case study of the World Health Organization's VigiBase® pharmacovigilance database between January 1, 2008, and December 31, 2018. The frequency of reports of ARF as a standardized Medical Dictionary for Regulatory Activities query for allopurinol and febuxostat was compared with that of all other reports for the two drugs and quoted as the reporting odds ratio (ROR) [95% confidence interval (CI)]. The results' stability was assessed in a series of sensitivity analyses (notably after the exclusion of putative competing drugs).

RESULTS

Among 3509 "suspected drug" notifications for febuxostat and 18,730 for allopurinol, we identified respectively 317 and 1008 cases of ARF. Acute renal failure was reported significantly more frequently for febuxostat and allopurinol than for other drugs (ROR [95%CI] 5.67 [5.05-6.36] and 3.25 [3.05-3.47], respectively). For both drugs, the ROR was higher in women than in men, respectively 11.60 [9.74-13.82] vs. 3.14 [2.69-3.67] for febuxostat and 4.45 [4.04-4.91] vs. 2.29 [2.11-2.50] for allopurinol. The sensitivity analyses confirmed the disproportionality for these two ULTs.

CONCLUSIONS

Acute renal failure was reported respectively 5.7 and 3.3 times more frequently for febuxostat and for allopurinol than for other drugs. Due to the potential consequences of ARF, physicians should take account of this disproportionality signal when prescribing the ULTs febuxostat and allopurinol.

Antioxidant, Anti-Melanogenic and Anti-Wrinkle Effects of Phellinus vaninii

In this study, the antioxidant, anti-xanthine oxidase, anti-melanogenic and anti-wrinkle effects of methanol (ME) and hot water (HE) extracts from the fruiting bodies of Phellinus vaninii were investigated. The 1,1-diphenyl-2-picryl-hydrazyl free radical scavenging activity of 2.0 mg/mL HE (95.38%) was comparable to that of butylated hydroxytoluene (96.97%), the reference standard. The hydroxyl radical scavenging activities of ME (98.19%) and HE (97.55%) were higher than that of butylated hydroxytoluene (92.66%) at 2.0 mg/mL. Neither ME nor HE was cytotoxic to murine melanoma B16-F10 cells at 25-750 µg/mL. Although the xanthine oxidase (XO) inhibitory effects of ME and HE were significantly lower than that of allopurinol, the values were higher than 84 percent. The in vitro tyrosinase inhibitory activities of ME and HE were comparable to kojic acid at 2.0 mg/mL. The cellular tyrosinase and melanin synthetic activities of ME and HE on B16-F10 melanoma cells at 500 µg/mL were higher than arbutin, indicating that the inhibitory effects of arbutin on the tyrosinase and melanin synthesis were higher than those of ME and HE. The collagenase inhibitory activity of HE was comparable to EGCG at 2.0 mg/mL, however, the elastase inhibitory activity of ME and HE was lower than EGCG at the concentration tested. The study results demonstrated that the fruiting bodies of Ph. vaninii possessed good antioxidant, anti-xanthine oxidase, cell-free anti-tyrosinase, cellular anti-tyrosinase, anti-collagenase, and moderate anti-elastase activities, which might be used for the development of novel anti-gout, skin-whitening, and skin anti-wrinkle agents.

Impact of urate-lowering drugs on the progression and recovery from chronic kidney disease among gout patients

Background

This study investigates the association between exposure to urate-lowering drugs (ULDs) and progression and recovery from chronic kidney disease (CKD).

Methods

We identified 5860 incident gout patients at Chang Gung Memorial Hospital from 2012 to 2015. Propensity score (PS)-weighted Cox proportional hazards model was used to estimate hazard ratios (HRs) for CKD progression and improvement. A separate analysis was conducted to assess the HR for CKD progression and CKD recovery among those with worsening CKD.

Results

The incidence of CKD progression among allopurinol, febuxostat and uricosuric agent users were 1.98, 1.88 and 1.64 per 1000 person-days. Compared with allopurinol users, the PS-weighted HR (95% confidence intervals [CIs]) was 1.77 (0.85–1.76) for febuxostat users and 1.37 (0.71–1.37) for uricosuric agent users for CKD progression and 1.43 (1.26–1.62) for febuxostat users and 1.00 (0.88–1.14) for uricosuric agent users for CKD improvement. Compared to allopurinol users, the HRs for CKD progression were 1.14 (0.80–1.66) for febuxostat users and 0.92 (0.67–1.31) for uricosuric agent users. Among 741 patients who had CKD progression, the incidence of CKD recovery was 1.33, 6.21 and 3.53 per 1000 person-days for allopurinol, febuxostat and uricosuric agent users. The HRs (95% CIs) for recovery in febuxostat and uricosuric agent users were 2.17 (1.40–3.47) and 1.80 (1.20–2.83) compared to allopurinol users.

Conclusions

CKD progression and recovery are common in gout patients using ULDs. Febuxostat and benzbromarone were associated with a similar risk of CKD progression with allopurinol, which has a poorer recovery compared with other ULDs.

Metabolomics analysis elucidates unique influences on purine / pyrimidine metabolism by xanthine oxidoreductase inhibitors in a rat model of renal ischemia-reperfusion injury

Background

Clinically applied as anti-gout drugs, xanthine oxidoreductase (XOR) inhibitors, especially the potent, selective, non-purine-analog XOR inhibitors febuxostat and topiroxostat, exert organ-protective effects. We tested the hypothesis that preservation of tissue concentrations of high-energy phosphates, such as ATP and ADP, contributes to organ-protective effects through CE-TOFMS metabolomics.

Methods

Rats were subjected to 30 min of renal ischemia-reperfusion (I/R) injury 60 min after oral administration of 10 mg/kg febuxostat, 10 mg/kg topiroxostat, 50 mg/kg allopurinol, or vehicle.

Results

In non-purine-analog XOR inhibitor-treated groups, renal concentrations of high-energy phosphates were greater before and after I/R injury, and renal adenine compounds were less depleted by I/R injury than in the vehicle and allopurinol groups. These findings were well in accordance with the proposed hypothesis that the recomposition of high-energy phosphates is promoted by non-purine-analog XOR inhibitors via the salvage pathway through blockade of hypoxanthine catabolism, whereas non-specific inhibitory effects of allopurinol on purine/pyrimidine enzymes impede this re-synthesis process.

Conclusions

This metabolic approach shed light on the physiology of the organ-protective effects of XOR inhibitors.

Electronic supplementary material

The online version of this article (10.1186/s10020-019-0109-y) contains supplementary material, which is available to authorized users.

Baseline characteristics of the autosomal-dominant polycystic kidney disease sub-cohort of the KoreaN cohort study for outcomes in patients with chronic kidney disease

AIM

The aim of this study was to describe the baseline characteristics of autosomal-dominant polycystic kidney disease (ADPKD) in a cohort of Korean patients with chronic kidney disease (CKD).

METHODS

From April 2011 to February 2016, patients with CKD stage 1-5 (pre-dialysis) were enrolled as an ADPKD sub-cohort of the KoreaN Cohort Study for Outcomes in Patients With Chronic Kidney Disease. Baseline characteristics, the correlation of kidney and liver volume and kidney function and the factors associated with kidney function were analysed.

RESULTS

A total of 364 ADPKD patients with a mean estimated glomerular filtration rate (eGFR) of 68.1 ± 33.3 mL/min per 1.73 m² (50.5% male with a mean age of 47.0 ± 10.6 years) were enrolled from nine hospitals in Korea. Initially, 55.8% of the patients were asymptomatic, and pain was the most common symptom (12.9%); 87.6 and 77.5% of the patients had hypertension and hepatic cysts, respectively. The height-adjusted total kidney volumes (htTKV) were higher in male patients than in female patients. In contrast, the height-adjusted total liver volumes were higher in female patients than in male patients. The decrease rate of eGFR depending on Log(htTKV) was larger in the group aged between 41 and 50 years than the other age groups. Older age, a higher 24-h urine protein excretion, larger htTKV and hyperuricemia were independently associated with lower eGFR, whereas using febuxostat was independently associated with higher eGFR.

CONCLUSION

This sub-cohort will provide clinical characteristics and outcomes of Korean ADPKD patients, which can be compared with those of other previous cohorts. We have identified factors associated with advanced-stage CKD in Korean patients with ADPKD.

Effects of febuxostat on renal function in patients with chronic kidney disease: A systematic review and meta-analysis

BACKGROUND/OBJECTIVE

Hyperuricemia has been proven to be an independent risk factor for chronic kidney disease (CKD). However, the role of hyperuricemia in the progression of CKD remains unclear. Thus, we performed a systematic review and meta-analysis to evaluate the efficacy and safety of febuxostat, a first line urate-lowering agent, in CKD patients with hyperuricemia.

METHODS

We have systematically searched for randomized controlled trials assessing the efficacy and safety of febuxostat versus control in CKD patients with hyperuricemia through MEDLINE, PubMed, EMBASE, and Cochrane databases. All statistical analyses were conducted by using the statistical package Review Manager, version 5.3.5. Heterogeneity was assessed using the Cochrane Q and I tests and summary statistics were reported with 95% confidence interval. Two-tailed test was used for analysis and a P value of <.05 is considered statistically significant.

RESULTS

Eleven eligible trials with 1317 participants were included in the meta-analysis. A significant reduction in serum uric acid was found in the febuxostat treated group. Also, a significant higher eGFR was found in the febuxostat treated group among CKD stage 3 and 4 patients. No significant difference of major complication or death was identified between treatment and control groups.

CONCLUSIONS

The meta-analysis showed that other than its urate-lowering effect, febuxostat presented a reno-protective effect in CKD patients. More studies with larger sample sizes and higher quality are required to clarify the role of febuxostat use in the progression of CKD.

Xanthine Oxidase Inhibition by Febuxostat in Macrophages Suppresses Angiotensin II-Induced Aortic Fibrosis

BACKGROUND

Several reports from basic researches and clinical studies have suggested that xanthine oxidase (XO) inhibitors have suppressive effects on cardiovascular diseases. However, the roles of a XO inhibitor, febuxostat (FEB), in the pathogenesis of vascular remodeling and hypertension independent of the serum uric acid level remain unclear.

METHODS

To induce vascular remodeling in mice, angiotensin II (Ang II) was infused for 2 weeks with a subcutaneously implanted osmotic minipump. FEB was administered every day during Ang II infusion. Aortic fibrosis was assessed by elastica van Gieson staining. Mouse macrophage RAW264.7 cells (RAW) and mouse embryonic fibroblasts were used for in vitro studies.

RESULTS

FEB suppressed Ang II-induced blood pressure elevation and aortic fibrosis. Immunostaining showed that Ang II-induced macrophage infiltration in the aorta tended to be suppressed by FEB, and XO was mainly colocalized in macrophages, not in fibroblasts. Transforming growth factor-β1 (TGF-β1) mRNA expression was induced in the aorta in the Ang II alone group, but not in the Ang II + FEB group. Ang II induced α-smooth muscle actin-positive fibroblasts in the aortic wall, but FEB suppressed them. XO expression and activity were induced by Ang II stimulation alone but not by Ang II + FEB in RAW. FEB suppressed Ang II-induced TGF-β1 mRNA expression in RAW.

CONCLUSIONS

Our results suggested that FEB ameliorates Ang II-induced aortic fibrosis via suppressing macrophage-derived TGF-β1 expression.

Febuxostat and Cardiovascular Events: A Systematic Review and Meta-Analysis

BACKGROUND

Febuxostat is approved in the United States for the management of hyperuricemia in patients with gout. In November 2017 the FDA released a warning alert on a possible link between febuxostat and cardiovascular disease (CVD) reported in a single clinical trial.

OBJECTIVE

To conduct a systematic review and meta-analysis and assess the risk of major adverse cardiovascular events (MACE) in patients receiving febuxostat compared to a control group.

METHODS

We searched the MEDLINE and EMBASE database for studies published up until March 2018. We included randomized clinical trials (RCTs) that compared febuxostat to control groups including placebo and allopurinol. We calculated the pooled relative risk (RR) of MACE and cardiovascular disease (CVD) mortality with the corresponding 95% confidence intervals (CI).

RESULTS

Our search yielded 374 potentially relevant studies. Among the 25 RCTs included in the systematic review, 10 qualified for the meta-analysis. Among the 14,402 subjects included, the median age was 54 years (IQR 52-67) and 90% were male (IQR 82-96); 8602 received febuxostat, 5118 allopurinol, and 643 placebo. The pooled RR of MACE for febuxostat was 0.9; 95% CI 0.6-1.5 (p= 0.96) compared to the control. The RR of CV-related death for febuxostat was 1.29; 95% CI 1.01-1.66 (p=0.03).

CONCLUSIONS

Compared with other SU-lowering treatments, febuxostat does not increase or decrease the risk of cardiovascular disease but may increase the risk of CVD death. More RCTs measuring cardiovascular safety as a primary outcome are needed to adequately evaluate the risk of CVD with febuxostat.

Pharmacological urate-lowering approaches in chronic kidney disease

Chronic kidney disease (CKD) has become a global public health issue and uric acid (UA) remains a major risk factor of CKD. As the main organ for the elimination of UA, kidney owned a group of urate transporters in tubular epithelium. Kidney disease hampered the UA excretion, and the accumulation of serum UA in return harmed the renal function. Commercially, there are three kinds of agents targeting at urate-lowering, xanthine oxidoreductase inhibitor which prevents the production of UA, uricosuric which increases the concentration of UA in urine thus decreasing serum UA level, and uricase which converts UA to allantoin resulting in the dramatic decrement of serum UA. Of note, in patients with CKD, administration of above-mentioned agents, alone or combined, needs special attention. New evidence is emerging for the efficacy of several urate-lowering drugs for the treatment of hyperuricemia in patients with CKD. Besides, loads of novel and promising drug candidates and phytochemicals are in the different phases of research and development. As of today, there is insufficient evidence to recommend the widespread use of UA-lowering therapy to prevent or slow down the progression of CKD. The review summarized the evidence and perspectives about the treatment of hyperuricemia with CKD for medicinal chemist and nephrologist.

Effects of febuxostat on serum cytokines IL-1, IL-4, IL-6, IL-8, TNF-α and COX-2

Effects of febuxostat on serum cytokines interleukin (IL)-1, IL-4, IL-6, IL-8, tumor necrosis factor-α (TNF-α) and cyclooxygenase-2 (COX-2) in patients with gout were investigated. A total of 80 patients with gout admitted and treated in the Affiliated Zhongshan Hospital of Dalian University from January 2015 to September 2017 were selected and divided into two groups by virtue of a random number table, with 40 patients in each group. All the enrolled patients received strict gout diet adjustment and took colchicine at the same time. Patients in the control group were additionally treated with allopurinol, while those in the the observation group were administered with febuxostat. The serum uric acid levels were compared between the two groups. The number of gout attacks and adverse reactions were recorded, and the variations in COX-2 positive value integral were clarified. At different time-points of observation, the serum uric acid levels in the observation group were significantly lower than those in the control group (p<0.05). Moreover, at 3 months after treatment, the levels of inflammatory cytokines in the serum in the observation group were decreased compared with those in the control group (p<0.05). The IL-1 and TNF-α levels were lower in the observation group at 1 week, 1 and 3 months after treatment compared with those in the control group (p<0.05). Furthermore, it was discovered that at 3 months after treatment, the COX-2 positive value integral in the observation group was superior to that in the control group (p<0.05). During follow-up, the number of gout attacks that needed medical intervention in the observation group was smaller than that in the control group (p<0.05). Compared with allopurinol therapy, febuxostat therapy can remarkably inhibit inflammatory responses in the body, relieve clinical symptoms and reduce relapse of the patients with gout.

Role of febuxostat in retarding progression of diabetic kidney disease with asymptomatic hyperuricemia: A 6-months open-label, randomized controlled trial

Introduction: Hyperuricemia is associated with chronic kidney disease (CKD) progression and poor cardiovascular outcomes. We studied the effect of febuxostat on estimated glomerular filtration rate (eGFR), proteinuria and monitored the safety profile of the medication.

Material and Methods: This is a prospective open-label, randomized study in CKD stage 3 and 4 patients with diabetic nephropathy and asymptomatic hyperuricemia. Patients were randomized into febuxostat 40 mg daily and no treatment group using block randomization method and were followed up for 6 months. Their usual care for diabetes mellitus, hypertension and dyslipidemia were continued in the study. Blood and urine investigations were monitored at baseline, 3 months and 6 months.

Results: The eGFR in febuxostat group was stabilized at 6 months with no significant reduction [26.2 (IQR 14.30) at baseline to 26.3 (IQR 15.2) ml/min/1.73 m²]. Whereas, there was a significant reduction of the eGFR in no treatment group from 28.2 (IQR 17.9) to 27.6 (IQR 19.3) ml/min/1.73 m² (p value < 0.01). We found the HbA1c (glycosylated hemoglobin) was significantly increased in febuxostat group from 7.2 ± 0.5 % at baseline to 7.6 ± 1.4 at 6 months (p value 0.04) but no significant change of HbA1c in the no treatment group. Proteinuria level was unchanged in both groups. The commonest adverse event was joint pain.

Conclusions: Febuxostat was able to preserve eGFR in CKD patients with diabetic nephropathy and this effect was beyond glycemic control. Increment of HbA1c level in febuxostat group needs further larger trials.