Four-week effects of allopurinol and febuxostat treatments on blood pressure and serum creatinine level in gouty men

Impact of Hyperuricemia and Urate-Lowering Agents on Cardiovascular Diseases

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

Assessing the causal relationships between gout and hypertension: a bidirectional Mendelian randomisation study with coarsened exposures

OBJECTIVES

Observational studies have demonstrated associations between gout and hypertension, but whether they are causal remains unclear. Our work aims to assess the causal relationship between gout and hypertension.

METHODS

We obtained genetic information from the Taiwan Biobank, including 88,347 participants and 686,439 single-nucleotide polymorphisms (SNPs). A novel model of Mendelian randomisation (MR) with coarsened exposures was used to examine the causality between the liability of gout on hypertension and vice versa, using 4 SNPs associated with gout and 10 SNPs associated with hypertension after removal of SNPs associated with measured confounders. The binary exposure (gout/hypertension) can be considered a coarsened approximation of a latent continuous trait. The inverse-variance weighted (IVW) and polygenic risk score (PRS) methods were used to estimate effect size. The MR analysis with coarsened exposures was performed with and without adjustments for covariates.

RESULTS

Of the 88,347 participants, 3253 (3.68%) had gout and 11,948 (13.52%) had hypertension (men, 31.9%; mean age 51.1 [SD, 11.1] years). After adjusting to measured confounders, MR analysis with coarsened exposures showed a significant positive causal effect of the liability of gout on hypertension in both the IVW method (relative risk [RR], 1.10; 95% confidence interval [CI], 1.03-1.19; p = 0.0077) and the PRS method (RR, 1.10; 95% CI, 1.02-1.19; p = 0.0092). The result of causality was the same before and after involving measured confounders. However, there was no causal effect of the liability of hypertension on gout.

CONCLUSIONS

In this study, we showed that the liability of gout has a causal effect on hypertension, but the liability of hypertension does not have a causal effect on gout. Adequate management of gout may reduce the risk of developing hypertension.

Synergistic Impacts of Alpinia oxyphylla Seed Extract and Allopurinol against Experimental Hyperuricemia

In traditional medicine, Alpinia oxyphylla Miquel seed has been used to treat gout and hyperuricemia-related symptoms by enhancing kidney functions. Allopurinol is the most commonly used drug to treat hyperuricemia; however, the drug has many adverse effects. Combining allopurinol with another compound could reduce the need for high doses and result in improved safety. We investigated the possible synergistic effects of Alpinia oxyphylla seed extract (AE) and allopurinol in decreasing urate concentrations in rats with potassium oxonate-induced hyperuricemia. This study evaluated the effects of allopurinol combined with AE on levels of serum urate, blood urea nitrogen (BUN), and creatinine in a hyperuricemic rat model. The effects of allopurinol plus AE on xanthine oxidase (XOD) activity and urate uptake were measured. The concomitant administration of allopurinol and AE normalized serum urate and reduced BUN and creatinine. The attenuation of hyperuricemia-induced impaired kidney function was related to downregulation of renal urate transporter 1 and upregulation of renal organic anion transporter 1, with inhibition of serum and hepatic XOD activities. The antihyperuricemic effects of allopurinol were enhanced when combined with AE. These results suggested that the combined use of allopurinol and AE may have clinical efficacy in treating hyperuricemia.

Febuxostat ameliorates high salt intake-induced hypertension and renal damage in Dahl salt-sensitive rats

OBJECTIVE

Several clinical studies have reported that xanthine oxidoreductase inhibitors have antihypertensive and renal protective effects but their mechanisms have not been fully determined. This study aims to clarify these mechanisms by examining the effects of febuxostat, which is a novel selective xanthine oxidoreductase inhibitor, in Dahl salt-sensitive rats.

METHODS

Eight-week-old male Dahl salt-sensitive rats were fed a normal salt (0.6% NaCl) or high salt (8% NaCl) diet for 8 weeks. A portion of the rats that were fed high salt diet were treated with febuxostat (3 mg/kg per day) simultaneously. Additionally, acute effects of febuxostat (3 mg/kg per day) were examined after high salt diet feeding for 4 or 8 weeks.

RESULTS

Treatment with febuxostat for 8 weeks attenuated high salt diet-induced hypertension, renal dysfunction, glomerular injury, and renal interstitial fibrosis. Febuxostat treatment reduced urinary excretion of H2O2 and malondialdehyde and renal thiobarbituric acid reactive substances content. High salt diet increased xanthine oxidoreductase activity and expression in the proximal tubules and medullary interstitium. Febuxostat completely inhibited xanthine oxidoreductase activity and attenuated the high salt diet-increased xanthine oxidoreductase expression. Febuxostat transiently increased urine volume and Na+ excretion without change in blood pressure or urinary creatinine excretion after high salt diet feeding for 4 or 8 weeks.

CONCLUSION

Febuxostat ameliorates high salt diet-induced hypertension and renal damage with a reduction of renal oxidative stress in Dahl salt-sensitive rats. The antihypertensive effect of febuxostat may be mediated in part by diuretic and natriuretic action.

The biology of urate

Urate is the end-product of the purine metabolism in humans. The dominant source of urate is endogenous purines and the remainder comes through diet. Approximately two thirds of urate is eliminated via the kidney with the rest excreted in the feces. While the transporter BCRP, encoded by ABCG2, has been found to play a role in both the gut and kidney, SLC22A12 and SLC2A9 encoding URAT1 and GLUT9, respectively, are the two transporters best characterized. Only 8-12% of the filtered urate is excreted by the kidney. Renal elimination of urate depends substantially on specific transporters, including URAT1, GLUT9 and BCRP. Studies that have assessed the biologic effects of urate have produced highly variable results. Although there is a suggestion that urate may have anti-oxidant properties in some circumstances, the majority of evidence indicates that urate is pro-inflammatory. Hyperuricemia can result in the formation of monosodium urate (MSU) crystals that may be recognized as danger signals by the immune system. This immune response results in the activation of the NLRP3 inflammasome and ultimately in the production and release of interleukin-1β, and IL-18, that mediate both inflammation, pyroptotic cell death, and necroinflammation. It has also been demonstrated that soluble urate mediates effects on the kidney to induce hypertension and can induce long term epigenetic reprogramming in myeloid cells to induce "trained immunity." Together, these sequelae of urate are thought to mediate most of the physiological effects of hyperuricemia and gout, illustrating this biologically active molecule is more than just an "end-product" of purine metabolism.

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.

Febuxostat as a renoprotective agent for treatment of hyperuricaemia: a meta-analysis of randomised controlled trials

BACKGROUND

The objective of this meta-analysis of randomised controlled clinical trials (RCT) was to evaluate the effects of febuxostat on kidney function in patients with hyperuricaemia.

AIMS

Febuxostat is a xanthine oxidase inhibitor that decreases uric acid production. Recent studies suggested the renoprotective effect of febuxostat among hyperuricaemia patients. The aim of this study was to evaluate the effects of febuxostat on kidney function in patients with hyperuricaemia.

METHODS

We conducted electronic searches in PubMed, Embase and Cochrane Central Register of Controlled Trials from January 1960 to July 2019 to identify RCT that examined the effects of febuxostat in adult patients with hyperuricaemia on serum creatinine, estimated glomerular filtration rate (eGFR), albuminuria, blood pressure parameters, major cardiovascular events, diarrhoea, joint pain, stroke and arrhythmia.

RESULTS

Nine RCT with 2141 participants were included in this meta-analysis. Compared to placebo, the febuxostat group showed a higher eGFR at 6 months with a weighted mean difference (WMD) of 2.86 mL/min/1.73 m² (P < 0.001), as well as the end of studies (eGFR WMD 2.69 mL/min/1.73 m² , P < 0.001). There was also lower serum creatinine (SrCr WMD = -0.04 mg/dL, P < 0.001), reduction in systolic blood pressure (SBP WMD = -1.18 mmHg, P < 0.001) and diastolic blood pressure (DBP WMD = -1.14 mmHg, P = 0.04). There was no statistical difference between febuxostat and placebo in major cardiovascular events, diarrhoea, joint symptoms, stroke events and arrhythmia. Subgroup analysis among chronic kidney disease showed the febuxostat group had higher eGFR than the placebo group (eGFR WMD = 2.69 mL/min/1.73 m² , P < 0.001).

CONCLUSION

Treating hyperuricaemia with febuxostat may slow the progression of chronic kidney disease irrespective of baseline renal function without significantly associated increased risks of major cardiovascular events, diarrhoea, joint symptoms, arrhythmia and stroke, compared to placebo.

Association Between Uric Acid, Carotid Intima-Media Thickness, and Cardiovascular Events: Prospective Results From the IMPROVE Study

Background The association between elevated serum uric acid (SUA), cardiovascular disease (CVD) risk, and carotid atherosclerosis has long been explored, and contrasting results have been reported. Therefore, the role of SUA as an independent risk factor for vascular events (VEs) and carotid atherosclerosis deserves further attention. We investigated the relationship between SUA, incident VEs, carotid intima-media thickness (cIMT), and cIMT progression in subjects at moderate-to-high CVD risk. Methods and Results In the IMPROVE (IMT-Progression as Predictors of VEs) study, 3686 participants (median age 64 years; 48% men) with ≥ 3 vascular risk factors, free from VEs at baseline, were grouped according to SUA quartiles (division points: 244-284-328 µmol/L in women, 295-336-385 µmol/L in men). Carotid-IMT and its 15-month progression, along with incident VEs, were recorded. A U-shaped association between SUA and VEs was observed in men, with 2.4-fold (P = 0.004) and 2.5-fold (P = 0.002) increased CVD risk in the first and fourth SUA quartiles as compared with the second. Adjusted hazard ratios (HRs) for cerebro-VEs in men were the highest (first and fourth quartile versus second: HR, 5.3, P = 0.010 and HR, 4.4, P = 0.023, respectively). SUA level was independently associated with cIMT progression in men (β = 0.068, P = 0.014). No significant association between SUA levels, CVD end points, and cIMT progression were found in women. Conclusions Both low and high SUA levels are associated with an increased risk of VEs in men at moderate-to-high CVD risk but not in women. Only elevated SUA levels predict cIMT progression and at a lesser but not significant extent in women.

Uric Acid and Hypertension: Prognostic Role and Guide for Treatment

The relationship between serum uric acid (SUA) and hypertension has been a subject of increasing interest since the 1870 discovery by Frederick Akbar Mahomed. Several epidemiological studies have shown a strong association between high SUA levels and the presence or the development of hypertension. Genetic analyses have found that xanthine oxidoreductase (XOR) genetic polymorphisms are associated with hypertension. However, genetic studies on urate transporters and Mendelian randomization studies failed to demonstrate a causal relationship between SUA and hypertension. Results from clinical trials on the role of urate-lowering therapy in the management of patients with hypertension are not uniform. Our study sought to analyze the prognostic and therapeutic role of SUA in the hypertensive disease, from uric acid (UA) biology to clinical trials on urate-lowering therapies.

Study on Network Pharmacological Analysis and Preliminary Validation to Understand the Mechanisms of Plantaginis Semen in Treatment of Gouty Nephropathy

Plantaginis Semen (PS) has been used to promote diuresis and clear away dampness. Recent reports have shown that PS can be used to treat gouty nephropathy (GN). However, the action and mechanism of PS have not been well defined in treating GN. The present study aimed to define the molecular mechanisms of PS as a potential therapeutic approach to treat GN. A combination of network pharmacology and validation experiments in GN is used to understand the potential mechanism. Information on pharmaceutically active compounds in PS and gene information related to GN was obtained from public databases. The compound target network and protein-protein interaction network were constructed to study the mechanism of action of PS in the treatment of GN. The mechanism of action of PS in the treatment of GN was analyzed via Gene Ontology (GO) biological process annotation and Kyoto Gene and Genomics Encyclopedia (KEGG) pathway enrichment. Validation experiments were performed to verify the core targets. The GN rat model was prepared by the method of combining yeast and adenine. Hematoxylin-eosin (HE) staining was used to observe the morphology of renal tissue in rats. ELISA was applied to detect TGF-β1, TNF-α, and IL-1β levels in renal tissue. The expressions of TGF-β1, TNF-α, and IL-1β were determined using immunohistochemistry. Through the results of network pharmacology, we obtained 9 active components, 118 predicted targets, and 149 GN targets from the public database. Based on the protein-protein interaction (PPI), 26 hub genes for interaction with PS treating for GN were screened, including MMP9, TNF, IL1β, and IL6. The enrichment analysis results showed that the treatment of GN with PS was mainly involved in the TGF-β1 signaling pathway, MAPK signaling pathway, TNF signaling pathway, NF-κB signaling pathway, and PI3K Akt signaling pathway. Validation experiment results showed that PS could reduce the content of urinary protein and UA and deregulate the expression of TGF-β1, TNF-α, and IL-1β in the treatment of GN. The molecular mechanism of PS in the treatment of GN indicated the synergistic features of multicomponent, multitarget, and multipathway of traditional Chinese medicine, which provided an essential scientific basis for further elucidating the mechanism of PS in the treatment of GN.

A randomized, double-blind, positive-controlled, prospective, dose-response clinical study to evaluate the efficacy and tolerability of an aqueous extract of Terminalia bellerica in lowering uric acid and creatinine levels in chronic kidney disease subjects with hyperuricemia

Background

Hyperuricemia is an independent risk factor in chronic kidney disease (CKD). Allopurinol and febuxostat are prescription medicines used to treat hyperuricemia but suffer side-effects. Earlier clinical study has shown that an aqueous extract of Terminalia bellerica (TBE), significantly reduced uric acid levels with no serious adverse effects in hyperuricemic subjects. The objective of this study is to determine the efficacy and tolerability of TB in reducing uric acid and creatinine levels in CKD subjects.

Methods

59-subjects were randomized to three groups-40 mg-once-daily febuxostat, 500 mg-twice-daily and 1000 mg-twice-daily of TBE. Serum uric acid, creatinine levels and estimated-glometular-filtration-rate were measured at baseline, 4, 8, 12, 16, 20, 24-weeks. Biomarkers of oxidative-stress, endothelial function, systemic inflammation, and platelet-aggregation were evaluated at baseline, 4, 8, 12, 24-weeks. Adverse drug reactions were recorded. Statistical analysis evaluated using GraphPadPrism4.

Results

55-subjects completed 24-week study. Starting at 4-weeks, all treatment groups showed a significant decrease in serum uric acid levels from baseline (p ≤ 0.0001). At 24-weeks, febuxostat, T.bellerica 500 mg-twice-daily, and T.bellerica 1000 mg-twice-daily doses decreased mean-percentage serum uric acid by 63.70 ± 4.62, 19.84 ± 6.43 and 33.88% ± 4.95% respectively (p ≤ 0.0001). Significant decrease in serum creatinine with all the groups starting at 16-weeks was seen (p ≤ 0.005-p ≤ 0.0001). At 24-weeks, the mean-percentage change in creatinine levels was 23.71 ± 12.50, 11.70 ± 9.0, and 24.42 ± 8.14, respectively with febuxostat, T.bellerica 500 mg-twice-daily and T.bellerica 1000 mg-twice-daily. Statistically significant (p ≤ 0.05) increase in estimated glomerular filtration rate-(eGFR) was seen at 20 (p ≤ 0.05) and 24-weeks (p ≤ 0.01) for both febuxostat vs T.bellerica 500 mg-twice-daily and T.bellerica 1000 mg-twice-daily vs T.bellerica 500 mg-twice-daily. There was no statistically significant difference between febuxostat and T.bellerica 1000 mg-twice-daily, with an increase of eGFR of 41.38 and 40.39 ml/min/1.73m² respectively, with the inference that T.bellerica at 1000 mg-twice-daily dose is as good as febuxostat 40 mg-once-daily. Positive improvements were made by all the groups in endothelial function and the related biomarkers and high-sensitivity C-reactive protein. None of the products showed effect on platelet aggregation.

Conclusion

In this 24-week study Febuxostat 40 mg, T. bellerica 500 mg-twice-daily and 1000 mg-twice-daily, significantly decreased the serum uric acid and creatinine levels, increased eGFR in CKD subjects. T. bellerica 500 mg-twice-daily and 1000 mg-twice-daily were one-third and more than half as effective at 24-weeks, respectively. T. bellerica extract may be considered a natural alternative for reducing serum uric acid levels.

Trial registration

This study was registered with the Clinical Trials Registry – India (CTRI) with the registration number: CTRI/2019/11/022093 [Registered on: 21/11/2019] Trial Registered Retrospectively.

Pharmacotherapy for hyperuricaemia in hypertensive patients

BACKGROUND

This is the second update of this systematic review. High blood pressure represents a major public health problem. Worldwide, approximately one-fourth of the adult population has hypertension. Epidemiological and experimental studies suggest a link between hyperuricaemia and hypertension. Hyperuricaemia affects 25% to 40% of those with untreated hypertension; a much lower prevalence has been reported in those with normotension or in the general population. However, whether lowering serum uric acid (UA) might lower blood pressure (BP), is an unanswered question.

OBJECTIVES

To determine whether UA-lowering agents reduce BP in people with primary hypertension or prehypertension, compared with placebo.

SEARCH METHODS

The Cochrane Hypertension Information Specialist searched the following databases for randomised controlled trials up to May 2020: the Cochrane Hypertension Specialised Register, CENTRAL 2018, Issue 12, MEDLINE (from 1946), Embase (from 1974), the World Health Organization International Clinical Trials Registry Platform, and ClinicalTrials.gov. We also searched LILACS (1982 to May 2020), and contacted authors of relevant papers regarding further published and unpublished work. The searches had no language or date restrictions.

SELECTION CRITERIA

To be included in this updated review, the studies had to meet the following criteria: 1) randomised or quasi-randomised, with a group assigned to receive a UA-lowering agent and another group assigned to receive placebo; 2) double-blind, single-blind, or open-label; 3) parallel or cross-over trial design; 4) cross-over trials had to have a washout period of at least two weeks; 5) minimum treatment duration of four weeks; 6) participants had to have a diagnosis of essential hypertension or prehypertension plus hyperuricaemia (serum UA greater than 6 mg/dL in women, 7 mg/dL in men, and 5.5 mg/dL in children or adolescents); 7) outcome measures included change in 24-hour ambulatory systolic or diastolic BP, or both; or clinic-measured systolic or diastolic BP, or both.

DATA COLLECTION AND ANALYSIS

The two review authors independently collected the data using a data extraction form, and resolved any disagreements via discussion. We assessed risk of bias using the Cochrane 'Risk of bias' tool. We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

In this review update, we screened 722 records, selected 26 full-text reports for evaluation. We identified no ongoing studies and did not add any new studies. We included three randomised controlled trials (RCTs), enrolling 211 people with hypertension or prehypertension, plus hyperuricaemia. Low-certainty evidence from three RCTs found inconclusive results between those who received UA-lowering drugs and placebo, in 24-hour ambulatory systolic (MD -6.2 mmHg, 95% CI -12.8 to 0.5) or diastolic BP (-3.9 mmHg, 95% CI -9.2 to 1.4). Low-certainty evidence from two RCTs found that UA-lowering drugs reduced clinic-measured systolic BP (-8.43 mmHg, 95% CI -15.24 to -1.62) but results for clinic-measured diastolic BP were inconclusive (-6.45 mmHg, 95% CI -13.60 to 0.70). High-certainty evidence from three RCTs found that serum UA levels were reduced by 3.1 mg/dL (95% CI 2.4 to 3.8) in the participants that received UA-lowering drugs. Low-certainty evidence from three RCTs found inconclusive results regarding the occurrence of adverse events between those who received UA-lowering drugs and placebo (RR 1.86, 95% CI 0.43 to 8.10).

AUTHORS' CONCLUSIONS

In this updated Cochrane Review, the current RCT data are insufficient to know whether UA-lowering therapy lowers BP. More studies are needed.

The Association of Febuxostat Compared With Allopurinol on Blood Pressure and Major Adverse Cardiac Events Among Adult Patients With Hyperuricemia: A Meta-analysis

Increased uric acid levels have been known to be associated with different cardiovascular and renal diseases. Over the past few years, several studies have examined the role of urate-lowering therapy (ULT) in hypertension and major adverse cardiac events (MACE) and suggest a potential role of elevated serum uric acid as an independent cardiovascular risk factor. This meta-analysis was done to determine the association of 2 ULTs commonly used in clinical practice (febuxostat vs. allopurinol) on hypertension and MACE and resolve the conflicting results of the outcomes of earlier studies. Randomized controlled trials comparing febuxostat versus allopurinol published with outcomes on blood pressure, all-cause mortality, myocardial infarction (MI), and stroke were searched through PubMed, Google Scholar, and Cochrane database. A total of 10 studies were subsequently included in the meta-analysis. Pooled analysis of the mean differences (MD) were done for the outcomes on blood pressure (systolic and diastolic) and risk ratios (RRs) for the outcomes on MACE with corresponding 95% confidence intervals (CIs). Pooled analysis of studies on hyperuricemic patients showed that febuxostat 40 mg has no significant difference compared with allopurinol 100/300 mg with respect to diastolic (MD, -0.56 with 95% CI of -4.28 to 3.15) and systolic blood pressure (MD, 0.30 with 95% CI of -3.33 to 3.93). No significant differences were also noted on all-cause mortality (RR, 1.18 with 95% CI of 0.99-1.41), MI (RR, 0.92 with 95% CI of 0.72-1.18), and stroke (RR, 1.05 with 95% CI of 0.77-1.43). The results of this meta-analysis showed that the 2 ULTs (febuxostat vs. allopurinol) have no significant association with respect to blood pressure among adult patients with hyperuricemia. No significant association was also noted of either ULT with all-cause mortality, MI, and stroke.

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.

Pegloticase Treatment Significantly Decreases Blood Pressure in Patients With Chronic Gout

Serum urate is correlated with blood pressure (BP), and lowering urate may decrease BP, but a consistent effect has not been observed. Here, we evaluated whether pegloticase, a recombinant uricase conjugated to polyethylene glycol, which can lead to persistently low serum urate levels (<1 mg/dL), can modulate BP in subjects with chronic refractory gout. This post hoc analysis used results from two 6-month randomized clinical trials in which subjects were treated with 8 mg pegloticase every 2 or 4 weeks (q2w or q4w) or placebo. Responders in this study were defined as those individuals in whom a persistently low urate level (<6 mg/dL and usually <1 mg/dL) was maintained. Serial sitting BP was measured in 173 subjects, and estimated glomerular filtration rate was determined at baseline and after 3 and 6 months. Significant reductions in mean arterial pressure (MAP) from baseline to 6 months were noted in q2w responders ( P=0.0028), whereas reductions in MAP in other groups were not significant. Significant decreases in both systolic and diastolic BP paralleled the change in MAP. Of the 62% of q2w responders exhibiting persistent decreases in MAP, there were no significant differences in baseline age, sex, race, weight, body mass index, history of hypertension, hyperlipidemia, history of coronary artery disease, gout duration, MAP, serum urate, estimated glomerular filtration rate or urinary uric acid/creatinine ratio compared with those who did not lower MAP. No significant changes in estimated glomerular filtration rate occurred in any of the groups during the study. Responders to biweekly pegloticase who maintained a persistently lower serum urate level throughout the trial experienced significant reductions in both systolic and diastolic BP that were independent of changes in renal function. Clinical Trial Registration- URL: http://www.clinicaltrials.gov . Unique identifier: NCT00325195.

Comparison of renoprotective effects of febuxostat and allopurinol in hyperuricemic patients with chronic kidney disease

PURPOSE

This study aimed to compare the renoprotective effect between febuxostat and allopurinol in hyperuricemic patients with chronic kidney disease (CKD), about which limited data are available.

METHODS

141 patients with stage 3 CKD and hyperuricemia were followed from June 2005 to April 2018. Thirty patients received febuxostat, 40 allopurinol and 71 conventional CKD management only (control group). We compared the mean serum uric acid levels, estimated glomerular filtration rate (eGFR) changes over time and renal survival time free from predefined renal disease progression among these 3 groups.

RESULTS

Overall, mean age was 62.6 ± 13.3 years, baseline eGFR 42.1 ± 8.8 mL/min/1.73 m², and serum uric acid 8.6 ± 1.5 mg/dL without intergroup difference. During the observation period (55.9 ± 31.8 months), febuxostat group, compared to both allopurinol and control group, had significantly lower mean serum uric acid levels (5.7 ± 1.0 vs. 7.1 ± 1.2 vs. 8.0 ± 0.8 mg/dL, p < 0.001) and maintained significantly higher mean eGFR values consistently for 4 years. Febuxostat group had significantly longer renal survival time free from renal disease progression than allopurinol and control group (87.7 (95% CI 71.2-104.2) vs. 77.6 (95% CI 60.2-94.9) vs. 48.7 (95% CI 39.3-58.1) months, respectively, p < 0.001). Cox proportional hazard model analysis adjusting for potent confounders revealed that febuxostat, with control group as reference, significantly reduced the risk of renal disease progression by 74.3% (hazard ratio 0.257 (95% CI 0.072-0.912), p = 0.036), while allopurinol showed insignificant result.

CONCLUSIONS

Febuxostat seems to reduce serum uric acid level and to retard renal disease progression more effectively than allopurinol in hyperuricemic patients with CKD.

Comparison of efficacy and safety between febuxostat and allopurinol in early post-renal transplant recipients with new onset of hyperuricemia

What is known and objective

Febuxostat and allopurinol are xanthine oxidase inhibitors for urate‐lowering therapy. The efficacy and safety of febuxostat and allopurinol have been mostly reported in hyperuricemia patients with normal renal function. Here, we aimed to compare the effects of these two drugs in early post‐renal transplant recipients, focusing on evaluating the urate‐lowering effect and recovery of allograft renal function.

Methods

A retrospective cohort study was performed in early post‐renal transplant recipients with new onset of hyperuricemia receiving febuxostat or allopurinol therapy. Serum uric acid (UA) and estimated glomerular filtration rate (eGFR) were detected on days 3, 7 and 15 and months 1, 3 and 6 after therapy initiation. Liver and blood functions were monitored and other adverse events were recorded.

Results and discussion

A total of 48 and 33 patients were enrolled in the febuxostat and allopurinol groups, respectively. Significant UA‐lowering effects were observed on day 3 in both groups. Febuxostat caused a more rapid UA decline, starting on day 3 and lasting for 1 month. The most apparent contrast was found in UA level (267.25 ± 93.66 vs 334.18 ± 96.56 μmol/L, P = 0.003) on day 7; 62.5% and 30.3% of patients achieved target UA level in febuxostat and allopurinol groups respectively on day 3 (P = 0.004), but there was no significant difference between two groups from days 15 to months 6. The median times to achieve target UA level were 3 and 5 days in febuxostat and allopurinol groups respectively (P = 0.002). The eGFR levels and recovering rates were gradually upregulated but no significant differences were found between two groups. No abnormities related to febuxostat or allopurinol were observed.

What is new and conclusion

This is the first comprehensive evaluation of UA‐lowering effects of febuxostat and allopurinol in early post‐renal transplant recipients. Febuxostat caused a marginally quicker serum UA‐lowering effect than allopurinol, but there was no advantage for long‐term use of febuxostat. The drugs had no significant differences in impacting renal allograft function recovery, and both were well tolerated.

Association of Chronic Kidney Disease With Allopurinol Use in Gout Treatment

IMPORTANCE

Clinicians are often cautious about use of allopurinol in patients with gout when renal function declines.

OBJECTIVE

To assess the association of allopurinol use in gout with the risk of developing chronic kidney disease stage 3 or higher.

DESIGN, SETTING, AND PARTICIPANTS

A time-stratified propensity score-matched, population-based, prospective cohort study of individuals with newly diagnosed gout who initiated allopurinol (≥300 mg/d) compared with those who did not initiate allopurinol, using the Health Improvement Network (THIN), a United Kingdom general practitioner electronic health records database, was carried out. The data were analyzed using Cox proportional hazards regression. Among adults aged 18 to 89 years with newly diagnosed gout, we propensity score matched 4760 initiators of allopurinol (≥300 mg/d) to the same number of noninitiators of allopurinol, excluding those with chronic kidney disease stage 3 or higher or urate-lowering therapy use before their gout diagnosis.

EXPOSURES

Allopurinol initiation at a dose of 300 mg or more per day.

MAIN OUTCOMES AND MEASURES

Development of chronic kidney disease stage 3 or higher.

RESULTS

Of the 4760 allopurinol initiators (3975 men, 785 women) and same number of noninitiators (3971 men, 789 women), 579 and 623, respectively, developed chronic kidney disease stage 3 or higher, with a mean follow-up time of 5 and 4 years, mean age of 57 years, and mean body mass index (calculated as weight in kilograms divided by height in meters squared) of 30 for both groups. Use of allopurinol of at least 300 mg/d was associated with lower risk of developing chronic kidney disease stage 3 or higher compared with nonusers, with a hazard ratio (HR) of 0.87 (95% CI, 0.77-0.97). Allopurinol initiation at less than 300 mg/d was not associated with renal function decline (HR, 1.00; 95% CI, 0.91-1.09).

CONCLUSIONS AND RELEVANCE

In this large cohort, allopurinol initiation of at least 300 mg/d was associated with a lower risk of renal function deterioration. Because allopurinol does not appear to be associated with renal function decline, clinicians should consider evaluating other potential causes when patients with gout experience renal function decline.

Dietary Sodium Intake and Serum Uric Acid: A Mini-Review

The aim of the present review is to summarize recent studies on the relationship between dietary sodium intake and serum uric acid concentration. In short-term dietary sodium intervention studies, including a recent further analysis of a previously published trial, high dietary sodium intake (200 mmol/day), compared with a low sodium diet (20-60 mmol/day), resulted in a significant reduction in serum uric acid, being approximately 20-60 μmol/L. This finding, though consistent across short-term studies, is in contradiction to the long-term observational evidence on the relationship between dietary sodium intake and serum uric acid. Indeed, in a population-based prospective study, high dietary sodium intake was associated with a higher serum uric acid concentration. If serum uric acid would be followed up, several currently ongoing long-term randomized dietary sodium intervention studies may shed some light on how dietary sodium intake interacts with serum uric acid in the development of hypertension.

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.

Xanthine Oxidase Inhibitors for Improving Renal Function in Chronic Kidney Disease Patients: An Updated Systematic Review and Meta-Analysis

BACKGROUND

Accruing evidence suggests that Xanthine Oxidase inhibitors (XOis) may bring direct renal benefits, besides those related to their hypo-uricemic effect. We hence aimed at performing a systematic review of randomized controlled trials (RCTs) to verify if treatment with XOis may improve renal outcomes in individuals with chronic kidney disease (CKD).

METHODS

Ovid-MEDLINE, PubMed and CENTRAL databases were searched for RCTs comparing any XOi to standard therapy or placebo. The primary endpoint of interest was progression to End-Stage Kidney Disease (ESKD); secondary endpoints were changes in serum creatinine, glomerular filtration rate (eGFR), proteinuria and albuminuria.

RESULTS

XOis treatment significantly reduced the risk of ESKD compared to the control (3 studies, 204 pts; RR = 0.42; 95% CI, 0.22, 0.80) and also improved eGFR in data pooled from RCTs with long follow-up times (>3 mo.) (4 studies, 357 pts; mean difference (MD) 6.82 mL/min/1.73 m²; 95% CI, 3.50, 10.15) and high methodological quality (blind design) (3 studies, 400 pts; MD 2.61 mL/min/1.73 m²; 95% CI, 0.23, 4.99). Conversely, no definite effects were apparently noticed on serum creatinine, proteinuria and albuminuria.

CONCLUSIONS

XOis may represent a promising tool for retarding disease progression in CKD patients. Future trials are awaited to confirm the generalizability of these findings to the whole CKD population.

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

Background

Hyperuricemia is reported to be related to rapid progression of renal function in patients with chronic kidney disease (CKD). Allopurinol, a uric acid lowering agent, protects renal progression. However, it is not widely used in patients with CKD because of its serious adverse event. Febuxostat can be alternatively used for patients who are intolerable to allopurinol. We aimed to determine renoprotective effect and urate-lowering effect between the two drugs.

Methods

We performed a systematic review and meta-analysis of randomized controlled trials to assess the effects of febuxostat compared to allopurinol in patients with hyperuricemia. MEDLINE, Embase, and Cochrane Library databases were searched to identify research publications.

Results

Four relevant publications were selected from among 3,815 studies. No significant differences were found in the changes in serum creatinine from baseline between the febuxostat and allopurinol groups. Changes in estimated glomerular filtration rate (eGFR) were observed between the two groups at 1 month (mean difference 1.65 mL/min/1.73 m², 95% confidence interval [CI] 0.38, 2.91 mL/min/1.73 m²; heterogeneity χ² = 1.25, I² = 0%, P = 0.01); however, the changes in eGFR were not significantly different at 3 months. A significant difference did exist in the changes in albuminuria levels from baseline between the febuxostat and allopurinol groups (mean difference −80.47 mg/gCr, 95% CI −149.29, −11.64 mg/gCr; heterogeneity χ² = 0.81, I² = 0%, P = 0.02). A significant difference was also observed in the changes in serum uric acid from baseline between the febuxostat and allopurinol groups (mean difference −0.92 mg/dL, 95% CI −1.29, −0.56 mg/dL; heterogeneity χ² = 6.24, I² = 52%, P < 0.001).

Conclusion

Febuxostat might be more renoprotective than allopurinol.

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.

Pharmacotherapy for hyperuricemia in hypertensive patients

BACKGROUND

High blood pressure represents a major public health problem. Worldwide, approximately one-fourth of the adult population has hypertension. Epidemiological and experimental studies suggest a link between hyperuricemia and hypertension. Hyperuricemia affects 25% to 40 % of individuals with untreated hypertension; a much lower prevalence has been reported in normotensives or in the general population. However, whether lowering serum uric acid (UA) might lower blood pressure (BP) is an unanswered question.

OBJECTIVES

To determine whether UA-lowering agents reduce BP in patients with primary hypertension or prehypertension compared with placebo.

SEARCH METHODS

The Cochrane Hypertension Information Specialist searched the following databases for randomized controlled trials up to February 2016: the Cochrane Hypertension Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL) (2016, Issue 2), MEDLINE (from 1946), Embase (from 1974), the World Health Organization International Clinical Trials Registry Platform, and ClinicalTrials.gov. We also searched LILACS up to March 2016 and contacted authors of relevant papers regarding further published and unpublished work.

SELECTION CRITERIA

To be included in this review, the studies had to meet the following criteria: 1) randomized or quasi-randomized, with a group assigned to receive a UA-lowering agent and another group assigned to receive placebo; 2) double-blind, single-blind or open-label; 3) parallel or cross-over trial; 4) cross-over trials had to have a washout period of at least two weeks; 5) minimum treatment duration of four weeks; 6) participants had to have a diagnosis of essential hypertension or prehypertension, and hyperuricemia (serum UA greater than 6 mg/dL in women, 7 mg/dL in men and 5.5 mg/dL in children/adolescents); 7) outcome measures assessed included change in clinic systolic, diastolic or 24-hour ambulatory BP.

DATA COLLECTION AND ANALYSIS

The two review authors independently collected the data using a data extraction form, and resolved any disagreements via discussion. We assessed risk of bias using the Cochrane Collaboration' Risk of bias' tool.

MAIN RESULTS

In this review update, we examined the abstracts of 349 identified papers and selected 21 for evaluation. We also identified three ongoing studies, the results of which are not yet available. Three other randomized controlled trials (RCTs) (two new), enrolling individuals with hypertension or prehypertension, and hyperuricemia, met the inclusion criteria for the review and were included in the meta-analysis. Low quality of evidence from three RCTs indicate no reduction in systolic (MD -6.2 mmHg, 95% CI -12.8 to 0.5) or diastolic (-3.9 mmHg, 95% CI -9.2 to 1.4) 24-hour ambulatory BP with UA-lowering drugs compared with placebo. Low quality of evidence from two RCTs reveal a reduction of systolic clinic BP (-8.43 mmHg, 95% CI -15.24 to -1.62) but not diastolic clinic BP (-6.45 mmHg, 95% CI -13.60 to 0.70). High quality of evidence from three RCTs indicates that serum UA levels were reduced by 3.1 mg/dL (95% CI 2.4 to 3.8) in the participants that received UA-lowering drugs. Very low quality of evidence from three RCTs suggests that withdrawals due to adverse effects were not increased with UA-lowering therapy (RR 1.86, 95% CI 0.43 to 8.10).

AUTHORS' CONCLUSIONS

In this updated systematic review, the RCT data available at present are insufficient to know whether UA-lowering therapy also lowers BP. More studies are needed.

Effect of uric acid-lowering therapy on blood pressure: systematic review and meta-analysis

BACKGROUND

The purpose of this meta-analysis was to determine if uric acid-lowering therapy is associated with a decrease in blood pressure (BP) and serum creatinine levels.

MATERIALS AND METHODS

Medline, Cochrane, EMBASE, and Google Scholar databases were searched until 29 June 2016, with keywords: uric-acid-lowering therapy, allopurinol, febuxostat, uricosuric, and BP. Only randomized controlled trials were included. The primary outcomes were reduction in systolic BP (SBP) and diastolic BP (DBP), and secondary was reduction in serum creatinine level.

RESULTS

Patients treated with allopurinol had greater reduction in SBP (standardized difference in means [SDM] = 0.321, 95% confidence interval [CI]: 0.145-0.497, p < 0.001), DBP (SDM = 0.260, 95% CI: 0.102 to 0.417, p = 0.001), and creatinine level (SDM = 0.312, 95% CI: 0.008 to 0.615, p = 0.044) than control patients. Subgroup analysis showed that allopurinol significantly decreased SBP whether or not antihypertensive drugs were being administered; a decrease in DBP was only seen in patients receiving antihypertensive drugs. Low-dose allopurinol (≤300 mg/day) was more effective at reducing SBP than high-dose (>300 mg/day) in patients receiving antihypertensive drugs.

CONCLUSIONS

These results support that allopurinol decreases BP and creatinine levels in patients with hyperuricemia. KEY MESSAGES Allopurinol decreases SBP and DPB, and creatinine levels in patients with hyperuricemia. Allopurinol resulted in a significant decrease in SBP in patients with or without treatment of antihypertensive drugs. A dose of allopurinol of ≤300 mg per day might be more effective than a higher dose.

Gout: will the "King of Diseases" be the first rheumatic disease to be cured?

Gout is the most common inflammatory arthritis in adults in the Western world. Characterized by hyperuricemia and the effects of acute and chronic inflammation in joints and bursa, gout leads to an agonizing, chronically painful arthritis. Arthritis can also be accompanied by urate nephropathy and subcutaneous urate deposits (tophi). Exciting new developments in the last decade have brought back the focus on this interesting, crystal-induced chronic inflammatory condition. New insights include the role of NALP3 inflammasome-induced inflammation in acute gout, the characterization of diagnostic signs on ultrasound and dual-energy computed tomography imaging modalities, the recognition of target serum urate less than 6 mg/day as the goal for urate-lowering therapies, and evidence-based treatment guidelines. A better understanding of disease mechanisms has enabled drug discovery - three new urate-lowering drugs have been approved in the last decade, with several more in the pipeline. We now recognize the important role that environment and genetics play in the causation of gout. A focus on the cardiac, renal, and metabolic comorbidities of gout will help translational research and discovery over the next decade.

Uric acid in metabolic syndrome: From an innocent bystander to a central player

Uric acid, once viewed as an inert metabolic end-product of purine metabolism, has been recently incriminated in a number of chronic disease states, including hypertension, metabolic syndrome, diabetes, non-alcoholic fatty liver disease, and chronic kidney disease. Several experimental and clinical studies support a role for uric acid as a contributory causal factor in these conditions. Here we discuss some of the major mechanisms linking uric acid to metabolic and cardiovascular diseases. At this time the key to understanding the importance of uric acid in these diseases will be the conduct of large clinical trials in which the effect of lowering uric acid on hard clinical outcomes is assessed. Elevated uric acid may turn out to be one of the more important remediable risk factors for metabolic and cardiovascular diseases.

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.