Renal Function in Gout: Long-Term Treatment Effects of Febuxostat

An artificial intelligence-based gout management system reduced chronic kidney disease incident and improved target serum urate achievement

OBJECTIVES

Stage ≥3 chronic kidney disease (CKD) affects ∼25% of people with gout. The effects of urate-lowering therapy (ULT) on CKD incidence and progression have remained inconclusive. Here, we assessed the impact of a gout ULT clinic intervention using artificial intelligence (AI) on CKD incidence and achievement of serum urate (SU) target.

METHODS

An observational study compared propensity score (PS)-matched gout cohorts from an AI-based Gout Intelligent Management System (GIMS) and a standard Electronic Medical Records system (EMRS) clinic database. The GIMS included a mobile application, data fusion interface and modules for expert consultation and laboratory results management. All patients had gout and a starting estimated glomerular filtration rate >60 ml/min. Using a 1:2 PS-matched cohort study design, we assessed the impact of the AI-based system on CKD outcomes and ULT effectiveness over 4 years of follow-up.

RESULTS

Compared with EMRS, GIMS was associated with reduced incidence of CKD stage ≥3. Specifically, 169/4117 new-onset CKD stage ≥3 (incidence 4.1 per 100 person-years) with GIMS compared with 164/2128 with EMRS (incidence 7.7 per 100 person-years) during follow-up. More participants achieved SU <6.0 mg/dl with GIMS versus EMRS during follow-up (49.8% vs 25.9%, P < 0.001).

CONCLUSION

Application of the artificial intelligence-based Gout Intelligent Management System was associated with lower incidence of chronic kidney disease stage ≥3 and superior target serum urate achievement in people with gout. The Gout Intelligent Management System represents a novel approach to improve real-world renal outcomes and urate-lowering therapy success in gout.

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.

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.

Prediction of renal and cardiometabolic outcomes in gout during urate-lowering therapy by sonography

OBJECTIVES

To assess whether the extent of monosodium urate (MSU) crystal deposition estimated by ultrasound could predict renal and cardiometabolic events during urate-lowering therapy (ULT).

METHODS

A prospective study on gout patients from two referral centers initiating ULT who underwent baseline ultrasound and were followed for 1 year. Ultrasound scans assessed six joints for double-contour (DC) signs and tophi. A five-point change (mL/min/1.73 m2 ) in the glomerular filtration rate at month 12 (M12) was considered significant. Outcomes of interest were renal function degraded versus improved and a composite cardiometabolic outcome (new hypertension, diabetes, atherosclerotic disease, and cardiovascular death). Homogeneity analyses and Cox regression models were performed.

RESULTS

One hundred sixty patients were recruited. At baseline, 81.1% of patients (n = 129) showed sonographic tophi with a mean number of 1.4 joints (±1.3) with a DC sign. At M12, 18 patients (11.3%) were lost to follow-up. The serum urate (SU) target (<6.0 mg/dL) was reached in 86 patients (69.9%). Regarding renal function, 15.9% of patients showed improvement, while in 31.0% it degraded. Fourteen new cardiometabolic events occurred in 12 patients. Neither the DC sign nor tophi showed any significant impact on the outcomes of interest. Baseline SU level was higher in those with renal improvement but not with renal decline, while achieving the SU target protected against new cardiometabolic events (HR = 0.2; 95% CI: 0.05-0.81).

CONCLUSIONS

Sonographic MSU crystal burden was unhelpful in predicting renal and cardiometabolic events during the first year of ULT. Reaching the SU target prevented cardiometabolic events, while its benefit in preserving/improving renal function is unclear.

Xanthine Oxidase Inhibitory Activity and Chemical Composition of Pistacia chinensis Leaf Essential Oil

Gout is a common metabolic disease caused by abnormal purine metabolism that promotes the formation and deposition of monosodium urate crystals within joints that causes acute arthritis and can seriously affect the daily life of patients. Pistacia chinensis is one of the traditional medicinal plants of the Anacardiaceae family, and there have been many studies on its biological activity, including anti-inflammatory, antidepressant, antibacterial, antioxidant, and hypoglycemic activities. The aim of this study was to evaluate the antigout effect of P. chinensis leaf essential oil and its constituents through xanthine oxidase inhibition. Leaf essential oil showed good xanthine oxidase inhibitory activity for both substrates, hypoxanthine and xanthine. Six fractions were obtained from open column chromatography, and fraction E1 exhibited the best activity. The constituents of leaf essential oil and fraction E1 were analyzed by GC-MS. The main constituents of both leaf essential oil and fraction E1 were limonene and 3-carene; limonene showed a higher inhibitory effect on xanthine oxidase. Based on the enzyme kinetic investigation, limonene was the mixed-type inhibitor against xanthine oxidase. The results revealed that Pistacia chinensis leaf essential oil and limonene have the potential to act as natural remedies for the treatment of gout.

Management and Cure of Gouty Arthritis

Gout is the most common inflammatory arthritis in the United States. Gouty arthritis is associated with significant morbidity and mortality and is the result of chronic hyperuricemia. Gout is effectively managed and potentially cured by decreasing the overall urate burden with serum urate-lowering therapy. When serum urate is maintained at less than 6.0 mg/dL, urate deposition is resolved, and gout can be cured. Unfortunately, because of less than optimal physician monitoring and dose escalation, many patients do not achieve these urate levels.

Management of gout in the primary care setting

Gout is a commonly treated inflammatory arthritis that is often managed in the primary care setting. This disease is prevalent among the multi-ethnic Malaysian population. Unfortunately, gout is still frequently managed sub-optimally, even in the hospital and primary care settings. Gout should be considered a major disease since it can potentially lead to multiple disabilities from joint destruction, nephropathy and increased cardiovascular morbidity and mortality. The objectives of this review are to summarise the latest updated information and management of gout in the primary care setting.

Molecular Biological and Clinical Understanding of the Pathophysiology and Treatments of Hyperuricemia and Its Association with Metabolic Syndrome, Cardiovascular Diseases and Chronic Kidney Disease

Uric acid (UA) is synthesized mainly in the liver, intestines, and vascular endothelium as the end product of an exogenous purine from food and endogenously from damaged, dying, and dead cells. The kidney plays a dominant role in UA excretion, and the kidney excretes approximately 70% of daily produced UA; the remaining 30% of UA is excreted from the intestine. When UA production exceeds UA excretion, hyperuricemia occurs. Hyperuricemia is significantly associated with the development and severity of the metabolic syndrome. The increased urate transporter 1 (URAT1) and glucose transporter 9 (GLUT9) expression, and glycolytic disturbances due to insulin resistance may be associated with the development of hyperuricemia in metabolic syndrome. Hyperuricemia was previously thought to be simply the cause of gout and gouty arthritis. Further, the hyperuricemia observed in patients with renal diseases was considered to be caused by UA underexcretion due to renal failure, and was not considered as an aggressive treatment target. The evidences obtained by basic science suggests a pathogenic role of hyperuricemia in the development of chronic kidney disease (CKD) and cardiovascular diseases (CVD), by inducing inflammation, endothelial dysfunction, proliferation of vascular smooth muscle cells, and activation of the renin-angiotensin system. Further, clinical evidences suggest that hyperuricemia is associated with the development of CVD and CKD. Further, accumulated data suggested that the UA-lowering treatments slower the progression of such diseases.

Pegloticase treatment of chronic refractory gout: Update on efficacy and safety

Gout is currently the most frequent cause of inflammatory arthritis worldwide. It results from elevated serum urate and subsequent deposition of monosodium urate crystals in joints and other tissues. While many patients with gout can be managed with conventional agents (e.g., allopurinol, febuxostat), those with chronic refractory gout often fail to achieve treatment goals with these agents. Pegloticase is a recombinant, pegylated mammalian uricase developed for treatment of chronic refractory gout. Pegloticase is different than other urate lowering therapies in that it enzymatically degrades urate. Pegloticase has been evaluated in multiple studies, most importantly in two randomized controlled trials and a follow-up open-label extension. Extensive analysis of results from these studies has shown that pegloticase profoundly lowers serum urate, resolves tophi, reduces tender and swollen joint counts, decreases pain, and improves both patients' global assessments and quality of life. Pegloticase also significantly decreases blood pressure in patients with chronic refractory gout, but has no significant effect on renal function. Post hoc analyses of clinical results also indicated that chronic refractory gout patients not achieving sustained urate lowering still have significant clinical benefits with pegloticase treatment. The major limitation of pegloticase is immunogenicity and the emergence of anti-drug antibodies that result in increased drug clearance, loss of efficacy, and infusion reactions. However, these reactions can be avoided by stopping pegloticase when there is a loss of serum urate lowering. New dosing regimens and co-administration of immunosuppressive agents are also being employed to overcome this limitation and extend the benefits of pegloticase to a larger number of patients.

Management and Cure of Gouty Arthritis

Gout is the most common inflammatory arthritis in the United States. Gouty arthritis is associated with significant morbidity and mortality and is caused by hyperuricemia. Gout is effectively managed and potentially cured by decreasing the overall urate burden with serum urate-lowering therapy. When serum urate is maintained at less than 6.0 mg/dL urate deposition is resolved and gout can be cured. Unfortunately, owing to a lack of physician monitoring and dose escalation the majority of patients do not achieve these urate levels.

Hyperuricemia and Hypertension, Coronary Artery Disease, Kidney Disease: From Concept to Practice

Since the publication of the Framingham Heart Study, which suggested that uric acid should no longer be associated with coronary heart disease after additional adjustment for cardiovascular disease risk factors, the number of publications challenging this statement has dramatically increased. The aim of this paper was to review and discuss the most recent studies addressing the possible relation between sustained elevated serum uric acid levels and the onset or worsening of cardiovascular and renal diseases. Original studies involving American teenagers clearly showed that serum uric acid levels were directly correlated with systolic and diastolic pressures, which has been confirmed in adult cohorts revealing a 2.21-fold increased risk of hypertension. Several studies involving patients with coronary artery disease support a role for serum uric acid level as a marker and/or predictor for future cardiovascular mortality and long-term adverse events in patients with coronary artery disease. Retrospective analyses have shown an inverse relationship between serum uric acid levels and renal function, and even a mild hyperuricemia has been shown to be associated with chronic kidney disease in patients with type 2 diabetes. Interventional studies, although of small size, showed that uric acid (UA)-lowering therapies induced a reduction of blood pressure in teenagers and a protective effect on renal function. Taken together, these studies support a role for high serum uric acid levels (>6 mg/dL or 60 mg/L) in hypertension-associated morbidities and should bring awareness to physicians with regards to patients with chronic hyperuricemia.

Hyperuricemia Predisposes to the Onset of Diabetes via Promoting Pancreatic β-Cell Death in Uricase-Deficient Male Mice

Clinical studies have shown a link between hyperuricemia (HU) and diabetes, while the exact effect of soluble serum urate on glucose metabolism remains elusive. This study aims to characterize the glucose metabolic phenotypes and investigate the underlying molecular mechanisms using a novel spontaneous HU mouse model in which the uricase (Uox) gene is absent. In an attempt to study the role of HU in glycometabolism, we implemented external stimulation on Uox knockout (KO) and wild-type (WT) males with a high-fat diet (HFD) and/or injections of multiple low-dose streptozotocin (MLD-STZ) to provoke the potential role of urate. Notably, while Uox-KO mice developed glucose intolerance in the basal condition, no mice spontaneously developed diabetes, even with aging. HFD-fed Uox-KO mice manifested similar insulin sensitivity compared with WT controls. HU augmented the existing glycometabolism abnormality induced by MLD-STZ and eventually led to diabetes, as evidenced by the increased random glucose. Reduced β-cell masses and increased terminal deoxynucleotidyl TUNEL-positive β-cells suggested that HU-mediated diabetes was cell death dependent. However, urate-lowering therapy (ULT) cannot ameliorate the diabetes incidence or reverse β-cell apoptosis with significance. ULT displayed a significant therapeutic effect of HU-crystal-associated kidney injury and tubulointerstitial damage in diabetes. Moreover, we present transcriptomic analysis of isolated islets, using Uox-KO versus WT mice and streptozotocin-induced diabetic WT (STZ-WT) versus diabetic Uox-KO (STZ-KO) mice. Shared differentially expressed genes of HU primacy revealed Stk17β is a possible target gene in HU-related β-cell death. Together, this study suggests that HU accelerates but does not cause diabetes by inhibiting islet β-cell survival.

Effect of Curcumin on Serum Urate in Asymptomatic Hyperuricemia: A Randomized Placebo-Controlled Trial

BACKGROUND/OBJECTIVE

Hyperuricemia leads to gout and renal complications and may increase cardiovascular risk. Curcumin inhibits xanthine oxidase and increases uricosuric activity and, as a result, decreases serum urate (SU). This randomized controlled trial aimed to determine the effects of curcumin versus placebo on SU in subjects with asymptomatic hyperuricemia (SU level ≥ 6 mg/dL in women or ≥ 7 mg/dL in men).

METHODS

Thirty-nine subjects with persistent hyperuricemia were randomized to receive curcumin (500-mg capsules twice daily, 20 subjects) or placebo (19 subjects). Primary outcome was the difference between SU before and 8 weeks after randomization. Secondary outcomes were differences between urine uric acid (UUA) clearance, fasting plasma glucose (FPG), and lipid profiles before and 8 weeks after randomization and adverse events.

RESULTS

Out of 39 subjects, there were no differences at baseline SU, UUA clearance, FPG, lipid profiles, and demographics between curcumin and placebo groups. After 8 weeks, SU was significantly decreased in both groups (6.9% in curcumin group, p = 0.002, and 5.0% in placebo group, p = 0.009). However, there was no difference in SU reduction between the two groups (p = 0.532). There were no differences in UUA, FPG, lipid profiles, or adverse events in either group at 8 weeks after randomization. The most common adverse event was diarrhea with no treatment required.

CONCLUSION

Curcumin was not superior to placebo in reducing serum urate and in increasing UUA clearance.

Mangiferin Ameliorates Hyperuricemic Nephropathy Which Is Associated With Downregulation of AQP2 and Increased Urinary Uric Acid Excretion

Hyperuricemia is characterized by abnormally high level of circulating uric acid in the blood and is associated with increased risk of kidney injury. The pathophysiological mechanisms leading to hyperuricemic nephropathy (HN) involve oxidative stress, endothelial dysfunction, inflammation, and fibrosis. Mangiferin is a bioactive C-glucoside xanthone, which has been exerting anti-inflammatory, anti-fibrotic, and antioxidative effects in many diseases. This study aimed to evaluate the effect of mangiferin treatment in HN. In a mouse model of HN, we observed lower circulating urate levels and ameliorated renal dysfunction with mangiferin treatment, which was associated with reduced renal inflammation and fibrosis. We next investigated the mechanism of urate lowering effect of mangiferin. Metabolic cage experiment showed that mangiferin-administrated mice excreted significantly more urinary uric acid due to elevated urine output, but no marked change in urine uric acid concentration. Expressions of water channels and urate transporters were further assessed by western blot. Renal AQP2 expression was decreased, yet urate transporters URAT1, GLUT9, and OAT1 expressions were not affected by mangiferin in HN mice. Moreover, mangiferin treatment also normalized xanthine oxidase and SOD activity in HN mice, which would decrease uric acid synthesis and improve oxidative stress, respectively. Therefore, our results reveal a novel mechanism whereby mangiferin can reduce serum uric acid levels by promoting AQP2-related urinary uric acid excretion. This study suggested that mangiferin could be a multi-target therapeutic candidate to prevent HN via mechanisms that involve increased excretion and decreased production of uric acid and modulation of inflammatory, fibrotic, and oxidative pathways.

Changeover Trial of Febuxostat and Topiroxostat for Hyperuricemia with Cardiovascular Disease: Sub-Analysis for Chronic Kidney Disease (TROFEO CKD Trial)

Background: The TROFEO trial demonstrated that febuxostat causes greater and more rapid reduction of serum uric acid (s-UA) than topiroxostat. We compared these drugs in patients with chronic kidney disease (CKD) by sub-analysis of the TROFEO trial.

Methods: This sub-analysis targeted patients with an estimated glomerular filtration rate (eGFR) ≤60 mL/min/1.73 m². The primary endpoint was the s-UA level. Secondary endpoints included creatinine, eGFR, urinary albumin, cystatin-C, oxidized low-density lipoprotein (Ox-LDL), eicosapentaenoic acid/arachidonic acid ratio, lipid biomarkers, high-sensitivity C-reactive protein, and B-type natriuretic peptide (BNP).

Results: There was no significant difference of s-UA between the two groups either before or after treatment. However, s-UA did not exceed 6.0 mg/dL in febuxostat group during the study period, but it exceeded this level in seven patients from topiroxostat group, with the number being significantly higher in topiroxostat group. Serum creatinine (s-Cr) and eGFR were significantly better after 6 months of febuxostat treatment compared with topiroxostat Cystatin-C was significantly lower after 6 months of febuxostat treatment compared with topiroxostat. The Ox-LDL was significantly lower after 3 and 6 months of febuxostat treatment compared with topiroxostat.

Conclusion: Febuxostat had stronger renoprotective and antioxidant effects than topiroxostat in patients with hyperuricemia and CKD.

Efficacy and Safety of Febuxostat Extended and Immediate Release in Patients With Gout and Renal Impairment: A Phase III Placebo-Controlled Study

Objective

To assess the efficacy and safety of febuxostat extended release (XR) and immediate release (IR) in patients with gout and normal or impaired renal function.

Methods

This was a 3‐month, phase III, multicenter, double‐blind, placebo‐controlled study. Patients (n = 1,790) with a history of gout and normal or impaired (mild‐to‐severe) renal function were randomized to receive placebo, febuxostat IR 40 or 80 mg, or febuxostat XR 40 or 80 mg once daily (1:1:1:1:1 ratio). End points included proportions of patients with a serum urate (UA) level of <5.0 mg/dl at month 3 (primary end point), a serum UA level of <6.0 mg/dl at month 3, and ≥1 gout flare requiring treatment over 3 months (secondary end points).

Results

Both febuxostat formulations led to significantly greater proportions of patients achieving a serum UA level of <5.0 mg/dl or <6.0 mg/dl at month 3 (P < 0.001 for all comparisons versus placebo). Equivalent doses of febuxostat XR and IR had similar treatment effects on serum UA level end points; however, a significantly greater proportion of patients achieved a serum UA level of <5.0 mg/dl with XR 40 mg versus IR 40 mg. Similar proportions of patients experienced ≥1 gout flare across treatment groups. Rates of treatment‐emergent adverse events were low and evenly distributed between treatment arms. A preplanned subgroup analysis demonstrated that febuxostat formulations were well tolerated and generally effective on serum UA level end points (versus placebo) across all renal function subgroups.

Conclusion

Both formulations of febuxostat (XR and IR) were well tolerated and effective in patients with gout and normal or impaired renal function, including patients with severe renal impairment.

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.

The Role of a “Treat-to-Target” Approach in the Long-Term Renal Outcomes of Patients with Gout

Background: Although gout is accompanied by the substantial burden of kidney disease, there are limited data to assess renal function as a therapeutic target. This study evaluated the importance of implementing a “treat-to-target” approach in relation to renal outcomes. Methods: Patients with gout who underwent continuous urate-lowering therapy (ULT) for at least 12 months were included. The effect of ULT on renal function was investigated by means of a sequential comparison of the estimated glomerular filtration rate (eGFR). Results: Improvement in renal function was only demonstrated in subjects in whom the serum urate target of <6 mg/dL was achieved (76.40 ± 18.81 mL/min/1.73 m2 vs. 80.30 ± 20.41 mL/min/1.73 m2, p < 0.001). A significant difference in the mean change in eGFR with respect to serum urate target achievement was shown in individuals with chronic kidney disease stage 3 (−0.35 ± 3.87 mL/min/1.73 m2 vs. 5.33 ± 11.64 mL/min/1.73 m2, p = 0.019). Multivariable analysis predicted that patients ≥65 years old had a decreased likelihood of improvement (OR 0.31, 95% CI 0.13–0.75, p = 0.009). Conclusions: The “treat-to-target” approach in the long-term management of gout is associated with better renal outcomes, with a greater impact on those with impaired renal function.

Uric acid and progression of chronic kidney disease

The association between serum uric acid levels and human disease has garnered intense interest over the last decade including chronic kidney disease. Animal studies have provided evidence for a potential mechanistic role of uric acid in promoting progression of chronic kidney disease. Epidemiologic studies have also suggested an association between elevated serum uric acid levels and worsening renal function in the general population as well as in patients with chronic kidney disease. However, there is currently insufficient evidence to recommend the use of uric acid-lowering therapy to delay progression of chronic kidney disease in this patient population. Adequately powered, randomized, placebo-controlled trials are required to more precisely evaluate the risk and benefits of uric acid-lowering therapy in pediatric patients.

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

RATIONALE & OBJECTIVE

Epidemiologic and clinical studies have suggested that urate-lowering therapy may slow the progression of chronic kidney disease (CKD). However, definitive evidence is lacking.

STUDY DESIGN

Randomized, double-blind, placebo-controlled trial.

SETTING & PARTICIPANTS

467 patients with stage 3 CKD and asymptomatic hyperuricemia at 55 medical institutions in Japan.

INTERVENTION

Participants were randomly assigned in a 1:1 ratio to receive febuxostat or placebo for 108 weeks.

OUTCOMES

The primary end point was the slope (in mL/min/1.73m² per year) of estimated glomerular filtration rate (eGFR). Secondary end points included changes in eGFRs and serum uric acid levels at 24, 48, 72, and 108 weeks of follow-up and the event of doubling of serum creatinine level or initiation of dialysis therapy.

RESULTS

Of 443 patients who were randomly assigned, 219 and 222 assigned to febuxostat and placebo, respectively, were included in the analysis. There was no significant difference in mean eGFR slope between the febuxostat (0.23±5.26mL/min/1.73m² per year) and placebo (-0.47±4.48mL/min/1.73m² per year) groups (difference, 0.70; 95% CI, -0.21 to 1.62; P=0.1). Subgroup analysis demonstrated a significant benefit from febuxostat in patients without proteinuria (P=0.005) and for whom serum creatinine concentration was lower than the median (P=0.009). The incidence of gouty arthritis was significantly lower (P=0.007) in the febuxostat group (0.91%) than in the placebo group (5.86%). Adverse events specific to febuxostat were not observed.

LIMITATIONS

GFR was estimated rather than measured, and patients with stages 4 and 5 CKD were excluded.

CONCLUSIONS

Compared to placebo, febuxostat did not mitigate the decline in kidney function among patients with stage 3 CKD and asymptomatic hyperuricemia.

FUNDING

Funded by Teijin Pharma Limited.

TRIAL REGISTRATION

Registered at the UMIN (University Hospital Medical Information Network) Clinical Trials Registry with study number UMIN000008343.

Recent pharmacological advances in the management of gout

Gout is the most common cause of inflammatory arthritis worldwide, and reports show that despite availability of therapies, management is still suboptimal. The new EULAR 2016 recommendations for the treatment of gout highlight the huge development in gout therapies, and the number of drugs being trialled only continues to increase. A clinical review of the evidence that underlies the recommendations from EULAR can reveal possible gaps in the literature and avenues for future research into gout therapies.

Efficacy and safety of febuxostat extended release and immediate release in patients with gout and moderate renal impairment: phase II placebo-controlled study

BACKGROUND

Febuxostat immediate release (IR), a xanthine oxidase inhibitor, is indicated for the management of hyperuricemia in patients with gout by lowering urate levels. An extended release (XR) formulation of febuxostat was developed to provide equal or superior efficacy on urate lowering compared with the IR formulation and potentially lower the risk of treatment-initiated gout flares due to an altered pattern of drug exposure. The present study evaluated the efficacy and safety of febuxostat XR and IR formulations in patients with gout and moderate renal impairment (estimated glomerular filtrate rate ≥ 30 and < 60 ml/min).

METHODS

This was an exploratory, 3-month, phase II, multicenter, placebo-controlled, double-blind proof-of-concept study. Patients (n = 189) were randomized 1:1:1:1:1 to receive placebo or febuxostat IR 40 mg, XR 40 mg, IR 80 mg, or XR 80 mg once daily. Endpoints included: proportion of patients with serum uric acid (sUA) < 5.0 mg/dl at month 3 (primary endpoint), proportion of patients with sUA < 6.0 mg/dl at month 3, and proportion of patients with ≥ 1 gout flare requiring treatment over 3 months.

RESULTS

At month 3, all febuxostat treatment groups were associated with greater proportions of patients achieving sUA < 5.0 mg/dl (p < 0.05 vs placebo). A greater proportion of patients receiving XR 40 mg achieved sUA < 5.0 mg/dl versus those receiving IR 40 mg (p = 0.034); proportions were similar in the IR 80 mg and XR 80 mg groups. Higher proportions of febuxostat-treated patients achieved sUA < 6.0 mg/dl at month 3 (p < 0.05 vs placebo) and experienced ≥ 1 gout flare (significant for all comparisons, except XR 40 mg). Incidences of treatment-related adverse events were low across all treatment groups; the majority were mild or moderate with no apparent trends correlating with IR or XR doses. The most common treatment-emergent adverse event was hypertension. One death (unrelated to the study drug) was reported.

CONCLUSIONS

These exploratory data demonstrate that febuxostat (XR and IR) formulations were effective and well tolerated in patients with gout and moderate renal impairment.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02128490 Registered on 29 April 2014.

Side Effects and Interactions of the Xanthine Oxidase Inhibitor Febuxostat

The paper addresses the safety of febuxostat and summarizes reports on side effects and interactions of febuxostat published by the cut-off date (last day of literature search) of 20 March 2018. Publications on side effects and the interactions of febuxostat were considered. Information concerning the occurrence of side effects and interactions in association with the treatment with febuxostat was collected and summarized in the review. The incidence of severe side effects was much less frequent than mild side effects (1.2–3.8% to 20.1–38.7%). The rate and range of febuxostat side effects are low at doses of up to 120 mg and only increase with a daily dose of over 120 mg. The publications reveal no age-dependent increase in side effects for febuxostat. In patients with impaired renal function, no increase in adverse events is described with a dose of up to 120 mg of febuxostat per day. Patients with impaired liver function had no elevated risk for severe side effects. A known allopurinol intolerance increases the risk of skin reactions during treatment with febuxostat by a factor of 3.6. No correlation between treatment with febuxostat and agranulocytosis has been confirmed. Possible interactions with very few medications (principally azathioprine) are known for febuxostat. Febuxostat is well tolerated and a modern and safe alternative to allopurinol therapy.

Improving adherence to gout therapy: an expert review

Gout is the most common form of inflammatory arthritis and is a considerable burden to patients and health care systems worldwide. Despite its clinical, economic, and social impact, patient persistence and adherence to prescribed urate-lowering therapies (ULT), ranging from 20% to 70%, is considered to be among the poorest of all chronic conditions. The majority of gout patients consequently receive suboptimal benefits of their prescribed pharmacotherapies. As gout is associated with several comorbidities along with an increased risk of premature mortality, achieving improved outcomes through adherence to ULT is crucial. Adherence to medication is complex and multidimensional and includes a combination of treatment-, patient-, and physician-related factors. This review explores the factors related to ULT adherence with the overall aim of helping health care providers better understand the barriers to adherence. Several interventions targeting pharmacists, nurses, and patients are being investigated to improve adherence. Furthermore, enhanced awareness and understanding of the need to treat-to-target in order to improve patient outcomes is needed among health care professionals. Greater understanding of the multidimensional nature of non-adherence can help physicians to treat gout more effectively and empower patients to improve self-management of this long-term disease.

Design and Rationale for the Veterans Affairs "Cooperative Study Program 594 Comparative Effectiveness in Gout: Allopurinol vs. Febuxostat" Trial

BACKGROUND

Gout patients do not routinely achieve optimal outcomes related in part to suboptimal administration of urate lowering therapy (ULT) including first-line xanthine oxidase inhibitors allopurinol or febuxostat. Studies leading to the approval of febuxostat compared this agent to allopurinol in inappropriately low, fixed doses. We will compare allopurinol with febuxostat in gout using appropriately titrated doses of both agents and a "treat-to-target" strategy congruent with specialty guidelines.

METHODS

We have planned and initiated the Veterans Affairs (VA) Cooperative Study Program (CSP) 594, Comparative Effectiveness in Gout: Allopurinol vs Febuxostat study. This large double-blind, non-inferiority trial will enroll 950 gout patients randomized to receive allopurinol or febuxostat. Patients will be followed for a total of 72 weeks encompassing 3 distinct 24-week study phases. During Phase I (0-24 weeks), participants will undergo gradual dose titration of ULT until achievement of serum uric acid (sUA) <6.0 mg/dL or <5.0 mg/dL if tophi are present. Dose escalation will not be allowed during final three study visits of Phase 2 (24-48 weeks) and during Phase 3 (48-72 weeks). The primary study outcome is the proportion of participants experiencing at least one gout flare during Phase 3. Subsequent to the 72-week study, participants will be followed passively for up to 10 years after the study to assess long-term health outcomes.

CONCLUSION

With its completion, the VA Comparative Effectiveness in Gout: Allopurinol vs Febuxostat study will demonstrate the central role of gradual ULT dose escalation and a treat-to-target strategy in gout management.

Does Altered Uric Acid Metabolism Contribute to Diabetic Kidney Disease Pathophysiology?

PURPOSE OF REVIEW

Multiple experimental and clinical studies have identified pathways by which uric acid may facilitate the development and progression of chronic kidney disease (CKD) in people with diabetes. However, it remains uncertain if the association of uric acid with CKD represents a pathogenic effect or merely reflects renal impairment.

RECENT FINDINGS

In contrast to many published reports, a recent Mendelian randomization study did not identify a causal link between uric acid and CKD in people with type 1 diabetes. Two recent multicenter randomized control trials, Preventing Early Renal Function Loss in Diabetes (PERL) and FEbuxostat versus placebo rAndomized controlled Trial regarding reduced renal function in patients with Hyperuricemia complicated by chRonic kidney disease stage 3 (FEATHER), were recently designed to assess if uric acid lowering slows progression of CKD. We review the evidence supporting a role for uric acid in the pathogenesis of CKD in people with diabetes and the putative benefits of uric acid lowering.

Hyperuricemia, Acute and Chronic Kidney Disease, Hypertension, and Cardiovascular Disease: Report of a Scientific Workshop Organized by the National Kidney Foundation

Urate is a cause of gout, kidney stones, and acute kidney injury from tumor lysis syndrome, but its relationship to kidney disease, cardiovascular disease, and diabetes remains controversial. A scientific workshop organized by the National Kidney Foundation was held in September 2016 to review current evidence. Cell culture studies and animal models suggest that elevated serum urate concentrations can contribute to kidney disease, hypertension, and metabolic syndrome. Epidemiologic evidence also supports elevated serum urate concentrations as a risk factor for the development of kidney disease, hypertension, and diabetes, but differences in methodologies and inpacts on serum urate concentrations by even subtle changes in kidney function render conclusions uncertain. Mendelian randomization studies generally do not support a causal role of serum urate in kidney disease, hypertension, or diabetes, although interpretation is complicated by nonhomogeneous populations, a failure to consider environmental interactions, and a lack of understanding of how the genetic polymorphisms affect biological mechanisms related to urate. Although several small clinical trials suggest benefits of urate-lowering therapies on kidney function, blood pressure, and insulin resistance, others have been negative, with many trials having design limitations and insufficient power. Thus, whether uric acid has a causal role in kidney and cardiovascular diseases requires further study.

Effects of uric acid-lowering therapy in patients with chronic kidney disease: A meta-analysis

Background and objectives

The effects of uric acid-lowering therapy in patients with chronic kidney disease (CKD) remain uncertain. Therefore, we undertook a systematic review and meta-analysis to investigate the effects of uric acid-lowering agents on major clinical outcomes of CKD.

Design, setting, participants, and measurements

According to the pre-specified protocol that was registered with PROSPERO (No. CRD42016038030), we searched systematically in MEDLINE, EMBASE, and the Cochrane Library for trials up to February 2016. Prospective, randomized, controlled trials assessing the effects of uric acid-lowering agents on cardiovascular and kidney outcomes in patients with CKD were included. Random-effects analytical methods were used.

Results

Sixteen eligible trials were identified, providing data for 1,211 patients with CKD, including 146 kidney failure events and 69 cardiovascular events. Uric acid-lowering therapy produced a 55% relative risk (RR) reduction (95% confidence interval [95% CI], 31–64) for kidney failure events (P < 0.001), and a 60% RR reduction (95% CI, 17–62) for cardiovascular events (P < 0.001), but had no significant effect on the risk of all-cause death (RR, 0.86; 95% CI, 0.50–1.46). The mean differences in rate of decline in the estimated glomerular filtration rate (4.10 mL/min/1.73 m² per year slower in uric acid-lowering therapy recipients, 95% CI, 1.86–6.35) and the standardized mean differences in the change in proteinuria or albuminuria (−0.23 units of standard deviation greater in uric acid-lowering therapy recipients; 95% CI, −0.43 to −0.04) were also statistically significant.

Conclusions

Uric acid-lowering therapy seemed to improve kidney outcomes and reduce the risk of cardiovascular events in adults with CKD.

The role of urate-lowering treatment on cardiovascular and renal disease: evidence from CARES, FAST, ALL-HEART, and FEATHER studies

Hyperuricemia has long been known to cause gout, and has recently been correlated with cardiovascular disease, hypertension, and renal disease. In the last few years, several large clinical studies have confirmed that hyperuricemia is a significant and independent risk factor for hypertension, ischemic heart disease, and heart failure, after an extensive adjustment for almost all the possible confounding conditions. This article reviews published literature on the subject, and describes ongoing studies on the use of urate-lowering therapy for cardiovascular and renal diseases.

Impact of Febuxostat on Renal Function in Gout Patients With Moderate-to-Severe Renal Impairment

OBJECTIVE

Renal impairment is a risk factor for gout and a barrier to optimal gout management. We undertook this exploratory study to obtain data that have been heretofore limited regarding the safety and efficacy of febuxostat in patients with moderate-to-severe renal impairment (estimated glomerular filtration rate [GFR] 15-50 ml/minute/1.73 m(2) ).

METHODS

Ninety-six gout patients with moderate-to-severe renal impairment were enrolled in a 12-month multicenter, randomized, double-blind, placebo-controlled study. Patients were randomly assigned at a 1:1:1 ratio to receive 30 mg febuxostat twice daily, 40/80 mg febuxostat once daily, or placebo. The primary efficacy end point was the change in serum creatinine (Cr) level from baseline to month 12. Secondary end points included the change in estimated GFR from baseline to month 12 and the proportion of patients with a serum uric acid (UA) level of <6.0 mg/dl at month 12.

RESULTS

At month 12, there were no significant differences in the change in serum Cr level from baseline, or in the change in estimated GFR from baseline, in either febuxostat group compared to the placebo group. The proportion of patients with a serum UA level of <6.0 mg/dl at month 12 was significantly greater in both febuxostat groups compared to the placebo group (both P < 0.001). At least 1 treatment-emergent adverse event (TEAE) occurred in 78.1% of patients receiving 30 mg febuxostat twice daily, 87.5% of patients receiving 40/80 mg febuxostat once daily, and 78.1% of patients receiving placebo. TEAEs most frequently involved the categories of renal failure and impairment and renal function analyses.

CONCLUSION

Febuxostat proved to be efficacious in serum UA reduction and was well tolerated in gout patients with moderate-to-severe renal impairment. Patients randomly assigned to receive febuxostat demonstrated significantly lower serum UA levels and no significant deterioration in renal function.

Renal and Vascular Effects of Uric Acid Lowering in Normouricemic Patients With Uncomplicated Type 1 Diabetes

Higher plasma uric acid (PUA) levels are associated with lower glomerular filtration rate (GFR) and higher blood pressure (BP) in patients with type 1 diabetes (T1D). Our aim was to determine the impact of PUA lowering on renal and vascular function in patients with uncomplicated T1D. T1D patients (n = 49) were studied under euglycemic and hyperglycemic conditions at baseline and after PUA lowering with febuxostat (FBX) for 8 weeks. Healthy control subjects were studied under normoglycemic conditions (n = 24). PUA, GFR (inulin), effective renal plasma flow (para-aminohippurate), BP, and hemodynamic responses to an infusion of angiotensin II (assessment of intrarenal renin-angiotensin-aldosterone system [RAAS]) were measured before and after FBX treatment. Arterial stiffness, flow-mediated dilation (FMD), nitroglycerin-mediated dilation (GMD), urinary nitric oxide (NO), and inflammatory markers were measured before and after FBX treatment. Gomez equations were used to estimate arteriolar afferent resistance, efferent resistance (R_E), and glomerular hydrostatic pressure (P_GLO). FBX had a modest systolic BP-lowering effect in T1D patients (112 ± 10 to 109 ± 9 mmHg, P = 0.049) without impacting arterial stiffness, FMD, GMD, or NO. FBX enhanced the filtration fraction response to hyperglycemia in T1D patients through larger increases in R_E, P_GLO, and interleukin-18 but without impacting the RAAS. FBX lowered systolic BP and modulated the renal R_E responses to hyperglycemia but without impacting the RAAS or NO levels, suggesting that PUA may augment other hemodynamic or inflammatory mechanisms that control the renal response to hyperglycemia at the efferent arteriole. Ongoing outcome trials will determine cardiorenal outcomes of PUA lowering in patients with T1D.

Treatment of asymptomatic hyperuricemia in chronic kidney disease: A new target in an old enemy - A review

Asymptomatic hyperuricemia is increasing in prevalence. There is a growing body of literature suggesting that uric acid has deleterious effects on vascular health and renal histological integrity. Several trials, reviewed herein, suggest that lowering the serum uric acid level is associated with a slowing in the rate of renal deterioration in those with chronic kidney disease. Given that there is little available in the general armamentarium to slow the rate of kidney deterioration, strong consideration could be given to the administration of agents or lifestyle changes that decrease uric acid production in hyperuricemic patients with deteriorating kidney function.

Management of Gout and Hyperuricemia in CKD

Hyperuricemia and gout, the clinical manifestation of monosodium urate crystal deposition, are common in patients with chronic kidney disease (CKD). Although the presence of CKD poses additional challenges in gout management, effective urate lowering is possible for most patients with CKD. Initial doses of urate-lowering therapy are lower than in the non-CKD population, whereas incremental dose escalation is guided by regular monitoring of serum urate levels to reach the target level of <6mg/dL (or <5mg/dL for patients with tophi). Management of gout flares with presently available agents can be more challenging due to potential nephrotoxicity and/or contraindications in the setting of other common comorbid conditions. At present, asymptomatic hyperuricemia is not an indication for urate-lowering therapy, though emerging data may support a potential renoprotective effect.

Serum uric acid and acute kidney injury: A mini review

Acute kidney injury causes great morbidity and mortality in both the community and hospital settings. Understanding the etiological factors and the pathophysiological principles resulting in acute kidney injury is essential in prompting appropriate therapies. Recently hyperuricemia has been recognized as a potentially modifiable risk factor for acute kidney injury, including that associated with cardiovascular surgery, radiocontrast administration, rhabdomyolysis, and associated with heat stress. This review discussed the evidence that repeated episodes of acute kidney injury from heat stress and dehydration may also underlie the pathogenesis of the chronic kidney disease epidemic that is occurring in Central America (Mesoamerican nephropathy). Potential mechanisms for how uric acid might contribute to acute kidney injury are also discussed, including systemic effects on renal microvasculature and hemodynamics, and local crystalline and noncrystalline effects on the renal tubules. Pilot clinical trials also show potential benefits of lowering uric acid on acute kidney injury associated with a variety of insults. In summary, there is mounting evidence that hyperuricemia may have a significant role in the development of acute kidney injury. Prospective, placebo controlled, randomized trials are needed to determine the potential benefit of uric acid lowering therapy on kidney and cardio-metabolic diseases.

Plasma uric acid effects on glomerular haemodynamic profile of patients with uncomplicated Type 1 diabetes mellitus

AIMS

Increased plasma uric acid (PUA) levels are associated with impaired renal function in patients with Type 1 diabetes, but the mechanisms are not well understood. Our aim was to evaluate whether higher PUA levels are associated with increased afferent arteriolar resistance in patients with Type 1 diabetes vs. healthy controls, thereby influencing renal function.

METHODS

PUA, GFR (inulin) and effective renal plasma flow (ERPF; para-aminohippurate) were measured in 70 otherwise healthy patients with Type 1 diabetes and 60 healthy controls. Gomez's equations were used to estimate afferent (RA ) and efferent (RE ) arteriolar resistances, glomerular hydrostatic pressure (PGLO ) and filtration pressure (ΔPF ). The relationships between PUA and glomerular haemodynamic parameters were evaluated by univariable linear regression correlation coefficients.

RESULTS

In patients with Type 1 diabetes, higher PUA correlated with lower PGLO (P = 0.002) and ΔPF (P = 0.0007), with higher RA (P = 0.001), but not with RE (P = 0.55). These associations were accompanied by correlations between higher PUA with lower GFR (P = 0.0007), ERPF (P = 0.008), RBF (P = 0.047) and higher RVR (P = 0.021). There were no significant correlations between PUA and renal haemodynamic parameters in the healthy controls.

CONCLUSIONS

The association between higher PUA with lower GFR and lower ERPF in patients with Type 1 diabetes is driven by alterations in the estimated RA . PUA-mediated RA may be caused by increased tone or thickening of the afferent renal arteriole, which might potentiate renal injury by causing ischaemia to the renal microcirculation.

Effect of Febuxostat, a Xanthine Oxidase Inhibitor, on Cardiovascular Risk in Hyperuricemic Patients with Hypertension: A Prospective, Open-label, Pilot Study

BACKGROUND AND OBJECTIVE

There is growing evidence of an association between high uric acid (UA) levels and cardiovascular disease (CVD). We hypothesized that febuxostat, a xanthine oxidase inhibitor, may be associated with suppressing the renin-angiotensin-aldosterone system (RAAS) and improving renal function in hyperurecemic patients with hypertension.

METHODS

We conducted a 6-month prospective study in which we randomized hypertensive hyperuricemic patients to either a febuxostat group (n = 30) or a control group (n = 30). The dose of febuxostat was adjusted to maintain the serum UA level at <6.0 mg/dL.

RESULTS

In the febuxostat group, the plasma renin activity (PRA), plasma aldosterone concentration (PAC), and serum UA level significantly decreased by 33 % (p = 0.0012), 14 % (p = 0.001), and 29 % (p < 0.0001), respectively. The estimated glomerular filtration rate (eGFR) significantly increased by 5.5 % (p = 0.001). Similar changes were not observed in the control group. Furthermore, a significant correlation was observed between the percent changes in the serum UA levels and the percent changes in the PRA (r = 0.277, p = 0.033), PAC (r = 0.310, p = 0.016), serum blood urea nitrogen levels (r = 0.434, p = 0.0005), serum creatinine levels (r = 0.413, p = 0.002), and eGFR (r = -0.474, p = 0.0001).

CONCLUSIONS

These results support the hypothesis that febuxostat might not only reduce serum UA levels but also suppress RAAS and improve renal function in hyperuricemic patients with hypertension, possibly leading to prevention of CVD.

Safety and efficacy of oral febuxostat for treatment of HLA-B*5801-negative gout: a randomized, open-label, multicentre, allopurinol-controlled study

Objectives: This phase IIIB study compared the efficacy and safety of febuxostat and allopurinol in gout patients with or without tophi who were HLA-B*5801 negative.

Method: Eligible patients were randomized to a febuxostat group (80 mg QD) or an allopurinol group (300 mg QD). Following an initial 2-week washout period, over the next 12 weeks we made five measurements of serum urate levels along with assessments of adverse events (AEs).

Results: Forty-three out of 152 screened subjects (28.3%) were ineligible either because of the presence of the HLA-B*5801 allele or for various other reasons. The febuxostat group (n = 54) and the allopurinol group (n = 55) had no significant differences in demographic or baseline characteristics. From week 2 to week 12, the febuxostat group had a significantly lower serum urate level than the allopurinol group (p ≤ 0.001 for all comparisons) and significantly more patients with serum urate levels less than 6.0 mg/dL. The serum urate levels of the febuxostat group declined by more than 40% from week 2 to week 12 and this decrease was greater than that in the allopurinol group (~30%). The two groups were similar in terms of AEs.

Conclusions: Febuxostat was more effective than allopurinol in reducing the serum urate levels of Han Chinese patients with gout or tophaceous gout who were HLA-B*5801 negative, without causing any serious skin reactions. Febuxostat should be considered for treatment of Han Chinese patients with gout who are HLA-B*5801 negative.

Comparison of the Renoprotective Effect of Febuxostat for the Treatment of Hyperuricemia between Patients with and without Type 2 Diabetes Mellitus: A Retrospective Observational Study

Objective The effects of febuxostat therapy on hyperuricemia in patients with and without type 2 diabetes were compared in this retrospective observational study after pair-matching using the propensity scores. Methods In total, 160 patients with hyperuricemia were studied as the treated set, and the 155 subjects in whom the administration of febuxostat was not discontinued during the observation period were investigated in the full analysis. The study subjects were divided into two groups based on the style of initiation of febuxostat: initial and switching therapy from allopurinol administration. Results The reduction in the serum uric acid (sUA) levels at six months after the initiation of febuxostat administration did not significantly differ between the patients with and without diabetes in both the initial (206±114 and 226±113 μmol/L in patients with and without diabetes, respectively) and switching (154±91 and 129±90 μmol/L in patients with and without diabetes, respectively) therapy groups. The eGFR values were significantly increased compared to the baseline levels only in the patients without diabetes. The changes in the eGFR values were significantly associated with the presence of diabetes and sUA at baseline in a multivariate analysis. The frequency of adverse events was not significantly different between the patients with and without diabetes. Conclusion Although febuxostat exerted a similar sUA-lowering effect against hyperuricemia in patients with type 2 diabetes compared to those without, the renoprotective effect was attenuated in those with diabetes compared to nondiabetic subjects.

Urate-lowering therapy: current options and future prospects for elderly patients with gout

Gout is increasingly seen in the elderly population, in large part due to physiological decline in renal function with age, and as a result of therapy for comorbidities, in particular the use of diuretic therapies for hypertension and congestive heart failure. Urate-lowering therapy (ULT) is the cornerstone of successful long-term gout management with the aim of achieving a sustained reduction in urate (<0.36 mmol/L, or lower [<0.30 mmol/L] in those with tophi). After decades during which there has been relatively little interest in developing new agents to treat gout, the last 5-10 years has seen a plethora of new agents with several now used in routine clinical practice. There has also been a renewed focus on the optimal use of established ULT, specifically allopurinol, which remains the first-line therapy for most patients. There is emerging data on its use in patients with renal impairment and better recognition of risk factors of the rare but potentially lethal allopurinol hypersensitivity syndrome (AHS). Febuxostat, a new xanthine oxidase inhibitor, is now established in everyday practice. Uricosuric agents may be indicated in certain patient groups, whilst a new class of recombinant uricases (pegloticase) given by intravenous infusion may achieve dramatic and rapid urate-lowering effects. Cost and other factors have thus far limited its use to the very severe cases. Furthermore, increased understanding of urate metabolism has led to the development of a number of drugs currently under clinical evaluation. Common therapeutic targets are the urate transporters in the kidney and alternative xanthine oxidase inhibition pathways. These advances bode well for the better management of gout and hyperuricaemia in our elderly patients.

Uric acid as a biomarker and a therapeutic target in diabetes

Diabetic nephropathy is a long-standing microvascular complication of diabetes mellitus and is the leading cause of end stage renal disease in developed countries. Current therapeutic strategies used to prevent or delay diabetic nephropathy exert limited clinical protective effects and can have serious adverse effects. Thus, identification of new pharmacologic agents that protect against the initiation and progression of complications of diabetes is of the utmost importance. Uric acid (UA) recently emerged as an inflammatory factor that increases oxidative stress and promotes activation of the renin angiotensin aldosterone system. As a consequence, higher UA levels are associated with various stages of the onset and progression of diabetic nephropathy, including metabolic, cardiovascular and kidney function abnormalities. If UA-lowering drugs, such as the xanthine oxidase inhibitors, block the mechanisms responsible for micro- and macrovascular injury in diabetes, these agents could represent a critical step toward preventing the progression of diabetes. This review focuses on the evidence that supports serum UA levels as a biomarker of renal and cardiovascular risk and as a potential additional therapeutic target in diabetes.

Detrimental role of hyperuricemia on the cardio-reno-vascular system

A bulk of evidence now exists that links gout with adverse cardiovascular (CV) outcomes. However, continuing doubt remains as to whether hyperuricemia can be truly considered an independent major CV risk factor. In fact, many gouty patients who develop major CV and renal events also possess several traditional CV risk factors, the presence of which can potentially confound any relationship between gout and adverse CV events. This paper reviews the available evidence to determine whether sufficient proof exists from biological, epidemiological and clinical trial studies to support a causal relationship between gout and major CV and renal events. This review is based on a PubMed/Embase database search for articles on hyperuricemia and its impact on cardiovascular and renal function.