Long-term cardiovascular safety of febuxostat compared with allopurinol in patients with gout (FAST): a multicentre, prospective, randomised, open-label, non-inferiority trial

Investigation of the Inhibition Mechanism of Xanthine Oxidoreductase by Oxipurinol: A Computational Study

Xanthine oxidoreductase (XOR) is an enzyme found in various organisms. It converts hypoxanthine to xanthine and urate, which are crucial steps in purine elimination in humans. Elevated uric acid levels can lead to conditions like gout and hyperuricemia. Therefore, there is significant interest in developing drugs that target XOR for treating these conditions and other diseases. Oxipurinol, an analogue of xanthine, is a well-known inhibitor of XOR. Crystallographic studies have revealed that oxipurinol directly binds to the molybdenum cofactor (MoCo) in XOR. However, the precise details of the inhibition mechanism are still unclear, which would be valuable for designing more effective drugs with similar inhibitory functions. In this study, molecular dynamics and quantum mechanics/molecular mechanics calculations are employed to investigate the inhibition mechanism of XOR by oxipurinol. The study examines the structural and dynamic effects of oxipurinol on the pre-catalytic structure of the metabolite-bound system. Our results provide insights on the reaction mechanism catalyzed by the MoCo center in the active site, which aligns well with experimental findings. Furthermore, the results provide insights into the residues surrounding the active site and propose an alternative mechanism for developing alternative covalent inhibitors.

Update in uric acid, hypertension, and cardiovascular diseases

A direct relationship between serum uric acid levels and hypertension, cardiovascular, renal and metabolic diseases has been reported in many basic and epidemiological studies. Among these, high blood pression is one of the most common features associated with hyperuricemia. In this regard, several small-scale interventional studies have demonstrated a significant reduction in blood pressure in hypertensive or prehypertensive patients on uric acid-lowering drugs. These observation or intervention studies have led to affirm that there is a causal relationship between uric acid and hypertension. While the clinical association between uric acid and high blood pressure is notable, no clear conclusion has yet been reached as to whether lowering uric acid is beneficial to prevent cardiovascular and renal metabolic diseases. Recently, several prospective randomized controlled intervention trials using allopurinol and other uric acid-lowering drugs have been reported, and the results from these trials were almost negative, suggesting that the correlation between hyperuricemia and cardiovascular disease has no causality. However, it is important to note that in some of these recent studies there were high dropout rates and an important fraction of participants were not hyperuricemic. Therefore, we should carry caution in interpreting the results of these studies. This review article presents the results of recent clinical trials using uric acid-lowering drugs, focusing on hypertension and cardiovascular and renal metabolic diseases, and discusses the future of uric acid therapy.

Comparative Safety of Gout Treatment Strategies on Cardiovascular Outcomes Using Observational Data: Clone-censor-weight Target Trial Emulation Approach

BACKGROUND

We sought to examine the cardiovascular safety of intensive treat-to-target serum urate strategies for gout using Medicare claims data linked to electronic health record laboratory data.

METHODS

We selected patients with gout who initiated urate-lowering therapy. We emulated a hypothetical trial comparing the rate of major adverse cardiovascular events (nonfatal myocardial infarction, nonfatal stroke, and cardiovascular death) among seven different strategies over 24 months. Three aspects were considered in defining increasingly intensive strategies: (1) continuation of urate-lowering therapy, (2) serum urate monitoring, and (3) modification of urate-lowering therapy when serum urate >6 mg/dl. We applied the "clone-censor-weight" method to account for baseline and time-varying confounding.

RESULTS

We identified 4402 patients with gout who initiated urate-lowering therapy (mean age 77; male 60%). During a total of 6611 person-years (PY) of follow-up under usual care, the rate of major cardiovascular events (first and recurrent) was 4.5/100 PY (95% CI = 4.0, 5.1). The rate ratios (RRs) suggested reductions (RR point estimates 0.88-0.84) compared with usual care. All 95% CIs were imprecise, but their upper bounds excluded substantial increase in RRs. RRs were closer to 1.0 for the analysis focusing on the first major adverse cardiovascular event during follow-up and on comparison to the strategy requiring continuation of urate-lowering therapy (but not necessarily titration).

CONCLUSIONS

Our treatment strategy trial emulation did not find increased risk of major adverse cardiovascular events with intensive urate-lowering strategies. Results may provide reassurance of the cardiovascular safety of intensive treat-to-target serum urate strategies recommended by rheumatology societies.

Asymptomatic hyperuricaemia in chronic kidney disease: mechanisms and clinical implications

Asymptomatic hyperuricaemia (HU) is considered a pathogenic factor in multiple disease contexts, but a causative role is only proven for the crystalline form of uric acid in gouty arthritis and urate nephropathy. Epidemiological studies document a robust association of HU with hypertension, cardiovascular disease (CVD) and CKD progression, but CKD-related impaired uric acid (UA) clearance and the use of diuretics that further impair UA clearance likely accounts for these associations. Interpreting the available trial evidence is further complicated by referring to xanthine oxidase inhibitors as urate-lowering treatment, although these drugs inhibit other substrates, so attributing their effects only to HU is problematic. In this review we provide new mechanistic insights into the biological effects of soluble and crystalline UA and discuss clinical evidence on the role of asymptomatic HU in CKD, CVD and sterile inflammation. We identify research areas with gaps in experimental and clinical evidence, specifically on infectious complications that represent the second common cause of death in CKD patients, referred to as secondary immunodeficiency related to kidney disease. In addition, we address potential therapeutic approaches on how and when to treat asymptomatic HU in patients with kidney disease and where further interventional studies are required.

Gout and hyperuricaemia: modifiable cardiovascular risk factors?

Gout and hyperuricaemia are two clinical situations associated with an elevated risk of developing cardiovascular (heart failure, myocardial infarction, stroke) and metabolic and renal complications. One reason is probably related to the fact that the prevalence of hyperuricaemia and gout is high in clinical situations, which themselves involve a high cardiovascular risk, such as hypertension, diabetes, chronic kidney disease or obesity. However, recent studies suggest that hyperuricaemia may promote cardiovascular complications independently of other cardiovascular risk factors, by inducing chronic inflammation, oxidative stress, and endothelial dysfunction. The questions that arise today concern primarily the treatment of asymptomatic hyperuricaemia. Should it be treated to decrease the patients' cardiovascular risk and if so, starting from which level and towards which target? There are now several pieces of evidence indicating that this might be useful, but data from large studies are not unanimous. This review will discuss this issue as well as new well-tolerated treatments, such as febuxostat or SGLT2 inhibitors, which lower uric acid levels, prevent gout and lower the risk of cardio-renal events.

Urate-lowering therapy following a treat-to-target continuation strategy compared to a treat-to-avoid-symptoms discontinuation strategy in gout patients in remission (GO TEST Finale): study protocol of a multicentre pragmatic randomized superiority trial

BACKGROUND

Long-term gout treatment is based on reducing serum urate levels using urate-lowering therapy (ULT). Most guidelines recommend using a lifelong continuation treat-to-target (T2T) strategy, in which ULT is dosed or combined until a serum urate target has been reached and maintained. However, a frequently used alternative strategy in clinical practice is a treat-to-avoid-symptoms (T2S) ULT discontinuation strategy, with the possibility of restarting the medication. This latter strategy aims at an acceptable symptom state, regardless of serum urate levels. High-quality evidence to support either strategy for patients in prolonged remission while using ULT is lacking.

METHODS

We developed an investigator-driven pragmatic, open-label, multicentre, randomized, superiority treatment strategy trial (GO TEST Finale). At least 278 gout patients using ULT who are in remission (>12 months, preliminary gout remission criteria) will be randomized 1:1 to a continued T2T strategy (treatment target serum urate < 0.36 mmol/l) or switched to a T2S discontinuation strategy in which ULT is tapered to stop and restarted in case of (persistent or recurrent) flaring. The primary outcome is the between-group difference in the proportion of patients not in remission during the last 6 months of 24 months follow-up and will be analyzed using a two proportion z test. Secondary outcomes are group differences in gout flare incidence, reintroduction or adaptation of ULT, use of anti-inflammatory drugs, serum urate changes, occurrence of adverse events (with a special interest in cardiovascular and renal events), and cost-effectiveness.

DISCUSSION

This study will be the first clinical trial comparing two ULT treatment strategies in patients with gout in remission. It will contribute to more specific and unambiguous guideline recommendations and improved cost-effectiveness of long-term gout treatment. It also paves the way (exploratory) to individualized long-term ULT treatment. In this article, we elaborate on some of our trial design choices and their clinical and methodological consequences.

TRIAL REGISTRATION

International Clinical Trial Registry Platform (ICTRP) NL9245. Registered on 2 February 2021 (METC Oost-Nederland NL74350.091.20); EudraCT EUCTR2020-005730-15-NL. Registered on 11 January 2021.

Renal herb formula protects against hyperuricemic nephropathy by inhibiting apoptosis and inflammation

BACKGROUND

Hyperuricemic nephropathy may be induced by the elevation and accumulation of uric acid in kidney after hyperuricemia, which leads to kidney residential cells apoptosis and inflammation. Renal herb formula (RHF) is a self-designed formula based on traditional Chinese medicine theory and clinical practice in kidney disease treatment. In the literature available currently, there is not yet research article reporting the reno-protective effect of RHF against hyperuricemic nephropathy.

PURPOSE

This study was performed to analyze the bioactive compound profiles of RHF, evaluate its protective effects against hyperuricemic nephropathy, and investigate the mechanisms of actions regarding apoptosis and inflammation.

METHODS

Ultra-performance liquid chromatography with a diode-array detector was applied to establish fingerprint and chemical composition of RHF. Potassium oxonate was used to induce hyperuricemic nephropathy in mice, and uric acid was used to stimulate apoptosis and inflammatory response in HK-2 cells, while the mice and cells were treated with RHF to explore its reno-protective effects and mechanisms.

RESULTS

It was found that chlorogenic acid, neochlorogenic acid, cryptochlorogenic acid, and isochlorogenic acid A-C may be the characteristic components of RHF. RHF treatment could improve kidney functions in mice with hyperuricemic nephropathies, such as decreasing urine protein, uric acid, and creatinine and serum uric acid, creatinine, and urea nitrogen. Histopathological observations showed that RHF treatment ameliorated kidney glomerular hypotrophy, tubular damage, and inflammatory infiltration. Mechanism studies revealed that RHF inhibited kidney residential cell apoptosis and inflammatory response by targeting the p53-associated intrinsic apoptosis pathway and NF-κB-mediated inflammatory pathway.

CONCLUSION

Taken together, it could be concluded that RHF exerted reno-protective effects against hyperuricemic nephropathy through reducing apoptosis and inflammation. RHF and the bioactive compounds chlorogenic acid analogs as promising candidates may be developed into novel and effective drugs for hyperuricemic nephropathy treatment and management.

The Hong Kong Society of Rheumatology consensus recommendations for the management of gout

Gout is one of the most common noncommunicable diseases in Hong Kong. Although effective treatment options are readily available, the management of gout in Hong Kong remains suboptimal. Like other countries, the treatment goal in Hong Kong usually focuses on relieving symptoms of gout but not treating the serum urate level to target. As a result, patients with gout continue to suffer from the debilitating arthritis, as well as the renal, metabolic, and cardiovascular complications associated with gout. The Hong Kong Society of Rheumatology spearheaded the development of these consensus recommendations through a Delphi exercise that involved rheumatologists, primary care physicians, and other specialists in Hong Kong. Recommendations on acute gout management, gout prophylaxis, treatment of hyperuricemia and its precautions, co-administration of non-gout medications with urate-lowering therapy, and lifestyle advice have been included. This paper serves as a reference guide to all healthcare providers who see patients who are at risk and are known to have this chronic but treatable condition.

Epidemiology and treatment-related concerns of gout and hyperuricemia in Korean

Gout is the most common form of inflammatory arthritis that affects mainly middle-aged men, and there is clear evidence of an association between hyperuricemia and the risk for gout. Increasing prevalence of gout and hyperuricemia has been reported in many countries. The prevalence of gout and hyperuricemia are constantly increasing in Korea with the patients at risk for developing a variety of comorbidities. Although there have been studies on the association between gout or serum uric acid level and several neurodegenerative diseases, cancer, and cardiovascular mortality, the causal relationship between gout and these comorbidities are still unclear. The associations of substantial economic burden with hyperuricemia, gout attack, and suboptimal treatment are well known. Gout is a disease that requires lifelong management including lifestyle modification. However, gout is poorly managed worldwide although effective urate-lowering drugs exist. In this review, we addressed epidemiological studies and treatment-related problems in the Korean population with gout or hyperuricemia to obtain the best clinical outcomes and reduce their medical burden.

Effect of febuxostat on adverse events and mortality in gout in Taiwan: An interrupted time series analysis

OBJECTIVES

To evaluate the influence of febuxostat on adverse events and mortality in gout.

METHODS

We retrospectively enrolled patients with newly diagnosed gout and prescribed urate-lowering therapy between 2006 and 2017 from the Taiwan National Health Insurance Database. These patients were divided into 2 groups: with and without comorbidities (n = 294 847 and 194 539). An interrupted time series analysis with adjustments for demographics, comorbidities, and comedication by propensity score-based stabilized weights was used to compare the trend of adverse events and mortality before vs after febuxostat was introduced in 2012.

RESULTS

The proportion of febuxostat use gradually increased from 0% in 2012 to 30% in those with comorbidities and 10% in those without comorbidities in 2017. Allopurinol use decreased from 30% in 2012 to 10% in 2017. The slope of the 1-year incidence rate of Stevens-Johnson syndrome (SJS) or toxic epidermal necrolysis (TEN) (per 10 000 patients) significantly reduced after 2012 in those with and without comorbidities (-0.375 per quarter, P = .015 and -.253 per quarter, P = .049). The slope of the 3-year incidence rate of acute myocardial infarction (AMI) (per 1000 patients), percutaneous coronary intervention (PCI) (per 1000 patients), and all-cause mortality (per 100 patients) significantly increased after 2012 in those with comorbidities (+0.207 per quarter, P = .013; +.389 per quarter, P = .002; +.103 per quarter, P = .001).

CONCLUSIONS

Febuxostat may reduce SJS and TEN in all gout patients but increase AMI, PCI, and all-cause mortality in gout patients with comorbidities.

The Singapore Experience With Uncontrolled Gout: Unmet Needs in the Management of Patients

Gout is the most common type of inflammatory arthritis, and its impact on cardiovascular health and quality of life is often underestimated. The prevalence and incidence of gout are increasing globally. Further, ischemic heart disease (IHD) and chronic kidney disease (CKD) are prevalent in gout patients. Some unmet needs for gout management include physicians' low initiation rate of urate-lowering therapy (ULT) and poor treatment adherence in patients with gout. There is also a lack of randomized controlled trials that establish safe doses of acute and long-term treatment for gout, particularly in patients with IHD and stage 4 CKD and above (including end-stage renal failure). Furthermore, there is also a lack of studies showing optimal serum uric acid (SUA) target and validated clinical outcome measures, including disease activity and remission criteria for gout tailored to treat-to-target approaches and the high cost of newer gout medications. The causal relationship between asymptomatic hyperuricemia or gout with comorbidities such as IHD and CKD has yet to be fully elucidated. There is a pressing need for collaborative international efforts to address the overall suboptimal management of gout.

Cardiovascular and kidney outcomes of uric acid-lowering therapy in patients with different kidney functions: study protocol for a systematic review, pairwise and network meta-analysis

INTRODUCTION

Hyperuricaemia has been implicated in the development of kidney function in populations with chronic kidney disease; however, the benefits of urate-lowering therapy (ULT) remain uncertain in different clinical studies. The different kidney functions of enrolled populations and distinct pharmacokinetic characteristics of ULT might be of the essence for the contrasting results. In this study, we will synthesise all available data from randomised controlled trials (RCTs) and cohort studies, then evaluate the outcomes of ULT in patients stratified by different estimated glomerular filtration rate (eGFR) stratifications. Furthermore, we will attempt to explore a relatively optimal ULT regimen using a Bayesian network meta-analysis in different eGFRs.

METHODS AND ANALYSIS

We searched published and unpublished data from MEDLINE, EMBASE, the Cochrane Central Register of Controlled trials and ClinicalTrials.gov website (before March 2022) for RCTs and cohort studies without language restriction. In the pairwise meta-analysis, all regimens of ULT will be pooled as a whole and compared with controls in different eGFRs. The random-effects model will be applied to generate the summary values using the software Stata V.12.0 (StataCorp). Network meta-analysis within a Bayesian framework will be conducted to explore the relative efficacy profiles of different ULTs and to find optimal ULT in different eGFRs. The software of WinBUGS V.1.4.3 and R2WinBUGS package of R V.3.1.1 will be used in the network meta-analysis. Primary outcomes will be the occurrence of major cardiovascular events and kidney failure events. Secondary outcomes will include the rate of change in eGFR per year, all-cause death, changes in serum uric acid level and major adverse events. Two authors will independently review study selection, data extraction and quality assessment.

ETHICS AND DISSEMINATION

The meta-analysis does not require ethical certification. The results will be disseminated through publication in a peer-reviewed journal and through presentations at academic conferences.

PROSPERO REGISTRATION NUMBER

CRD42021226163.

`Risk of cardiovascular disease associated with febuxostat versus allopurinol use in patients with gout: a retrospective cohort study in Korea

Febuxostat is the drug used to treat hyperuricemia in patients with gout. Recently, the usage of Febuxostat has been controversial over the side effects in cardiovascular. The study aimed to comparatively analyze the risk of cardiovascular disease associated with febuxostat and allopurinol use in Korean patients with gout. A cohort study was conducted using national insurance claim data from the Health Insurance Review and Assessment Service (HIRA). Adult patients who were diagnosed with gout and prescribed febuxostat or allopurinol more than once from July 1, 2015, to June 30, 2018 were studied. The outcome was cardiovascular disease. Analysis was performed using Cox's proportional hazard model following 1:1 propensity score matching to estimate the hazard ratio with a 95% confidence interval. In total, 90,590 patients were defined as the final study cohort who had an average follow-up of 467 days, including 28,732 and 61,858 patients in the febuxostat and allopurinol groups, respectively. After the 1:1 propensity score matching, the risk of cardiovascular disease in the febuxostat group was significantly higher than in the allopurinol group (HR: 1.17; 95% CI: 1.10-1.24). In the sensitivity analysis, the risk of cardiovascular disease in the febuxostat group was significantly higher than in the allopurinol group (HR: 1.09; 95% CI: 1.04-1.15). However, further sensitivity analysis showed no statistically significant difference between the febuxostat group and allopurinol group after adjusting for cardiovascular disease history before the index date. Similarly, no statistically significant difference was found between the two drugs in the subgroup analysis. Febuxostat was not associated with a significantly increased risk of cardiovascular disease.

Assessment of the influence on left ventricle by potassium oxonate and hypoxanthine-induced chronic hyperuricemia

Cellular cytoplasmic xanthine oxidase (XO)-mediated uric acid synthesis and extracellular excess uric acid exposure are both causes of cardiomyocytic injury under the condition of hyperuricemia (HUA). Potassium oxonate suppresses uric acid degradation to increase extracellular concentration, while hypoxanthine is the catalytic substrate of XO. We aimed to observe cardiac damage in a chronic HUA mouse model induced by potassium oxonate and hypoxanthine. The mouse model was established by the co-administration of potassium oxonate and hypoxanthine for eight weeks. Then, left ventricular parameters were examined by echocardiographic evaluation, and the heart tissues were harvested for further histopathological analysis. The results showed that plasma uric acid was persistently elevated in the model mice, which demonstrated the stable establishment of chronic HUA. The left ventricular anterior wall was significantly thickened in the model group compared with the blank control group. After the end of modeling, the left ventricular anterior wall thickness of the hyperuricemic mice increased compared with that of blank group. The histological analysis showed and myocardial structure disorganization in the model group compared with the blank control. The above cardiac impairment changes could be attenuated by allopurinol pretreatment. This study systematically assessed cardiac damage in a chronic HUA mouse model. In addition, it provides useful information for future HUA-associated heart injury mechanism investigation and therapeutic treatment evaluation.

Atrial Fibrillation Risk and Urate-Lowering Therapy in Patients with Gout: A Cohort Study Using a Clinical Database

Individuals of Asian descent are at higher risk for developing hyperuricemia and gout as compared to Western populations. Urate-lowering therapy (ULT) is an effective treatment for hyperuricemia and gout. It was reported that febuxostat, one of the ULTs, raises the risk of atrial fibrillation (AF) in elderly populations. Nevertheless, this association has not been properly investigated in Asian populations. We aimed to investigate the development of AF after ULT with different drugs in an Asian population. We conducted a retrospective cohort study using the clinical database at Kaohsiung Veterans General Hospital. Patients newly diagnosed with gout between 1 January 2013 and 31 December 2020 and with a documented baseline serum uric acid (sUA) level but no prior diagnosis of AF were identified. Patients were divided into three groups-allopurinol, benzbromarone, and febuxostat users. During the follow-up period, the risks of incident AF following the initiation of ULT with different drugs were assessed. Development of incident AF was noted in 43 (6%) of the 713 eligible patients during the follow-up period (mean, 49.4 ± 26.6 months). Febuxostat-treated patients had a higher prevalence of certain comorbidities (diabetes mellitus, heart failure, and chronic kidney disease) and higher CHA2DS2-VASc scores. Compared with allopurinol, neither febuxostat nor benzbromarone was associated with increased adjusted hazard ratios (HR) for incident AF (HR: 1.20, 95% confidence interval [CI]: 0.43-3.34; HR: 0.68, 95% CI: 0.22-2.08). There was no difference in the risk of incident AF among Asian patients with gout who received febuxostat, allopurinol, or benzbromarone. Further studies are needed to evaluate long-term cardiovascular outcomes in patients receiving different ULT drugs.

Ganoderma lucidum polysaccharide peptide alleviates hyperuricemia by regulating adenosine deaminase and urate transporters

Hyperuricemia (HUA) affects human health and is involved in the pathogenesis of common chronic diseases. Previous studies showed that Ganoderma lucidum extract lowered HUA in animals. However, the active ingredient and pharmacological mechanism of Ganoderma lucidum extract in the improvement of HUA are unknown. The purpose of this study was to determine the anti-HUA efficacy and related mechanism of Ganoderma lucidum polysaccharide peptide (GLPP) using a potassium oxonate (PO)-induced mouse model and an adenosine-induced cell model. The experimental results showed that blood uric acid (UA) was decreased up to 40.6% by GLPP in HUA mice in a dose-dependent manner. Additionally, GLPP significantly reduced UA production by inhibiting the hepatic and blood adenosine deaminase (ADA) activity and increased UA excretion by decreasing the expression of glucose transporter 9 (GLUT9) and increasing the expression of organic anion transporter 1 (OAT1) in kidney. The adenosine-induced cell model showed that the inhibitory effect of GLPP on ADA activity may be the main reason for the alleviation of HUA by GLPP. Furthermore, PO-induced renal histopathological damage was also alleviated by GLPP in a dose-dependent manner. The experimental results in this study indicated that GLPP exerted anti-HUA effects via regulating the UA production and excretion, suggesting that GLPP could be developed into a therapeutic agent for HUA.

Superiority of Low-Dose Benzbromarone to Low-Dose Febuxostat in a Prospective, Randomized Comparative Effectiveness Trial in Gout Patients With Renal Uric Acid Underexcretion

OBJECTIVE

The predominant mechanism driving hyperuricemia in gout is renal uric acid underexcretion; however, the standard urate-lowering therapy (ULT) recommendation is first-line xanthine oxidase inhibitor (XOI), irrespective of the cause of hyperuricemia. This comparative effectiveness clinical trial was undertaken to compare first-line nontitrated low-dose benzbromarone (LDBen) uricosuric therapy to XOI ULT with low-dose febuxostat (LDFeb) in gout patients with renal uric acid underexcretion.

METHODS

We conducted a prospective, randomized, single-center, open-label trial in men with gout and renal uric acid underexcretion (defined as fractional excretion of urate <5.5% and uric acid excretion ≤600 mg/day/1.73 m2 ). A total of 196 participants were randomly assigned to receive LDBen 25 mg daily or LDFeb 20 mg daily for 12 weeks. All participants received daily urine alkalization with oral sodium bicarbonate. The primary end point was the rate of achieving the serum urate target of <6 mg/dl.

RESULTS

More participants in the LDBen group achieved the serum urate target than those in the LDFeb group (61% compared to 32%, P < 0.001). Rates of adverse events, including gout flares and urolithiasis, did not differ between groups, with the exception of greater transaminase elevation in the LDFeb group (4% for LDBen compared to 15% for LDFeb, P = 0.008).

CONCLUSION

Compared to LDFeb, LDBen has superior urate-lowering efficacy and similar safety in treating relatively young and healthy patients with renal uric acid underexcretion-type gout.

Novel urate transporter 1 (URAT1) inhibitors: a review of recent patent literature (2020-present)

INTRODUCTION

The urate transporter 1 (URAT1) is a membrane transporter located in the apical membrane of human renal proximal tubule epithelial cells, which mediates most of the reabsorption of urate. Hyperuricemia (HUA) is a common disease caused by metabolic disorders, which has been considered as the key factor of gout. Approximately 90% of patients suffer from hyperuricemia due to insufficient or poor uric acid excretion. Therefore, the drug design of URAT1 inhibitors targeting improve the renal urate excretion by reducing the reabsorption of urate anions represent a hot topic in searching for anti-gout drugs currently.

AREAS COVERED

In this review, we summarize URAT1 inhibitors patents reported since 2020 to present through the public database at https://worldwide.espacenet.com and some medicinal chemistry strategies employed to develop novel drug candidates.

EXPERT OPINION

Ligand-based drug design (LBDD) strategies have been frequently used developing new URAT1 inhibitors. Meanwhile, the discovery of dual drugs targeting both inhibition of xanthine oxidase (XOD) and URAT1 may be an emerging horizon for designing novel uric acid-lowering candidates in future. Furthermore, advanced techniques in the field of molecular biology and computer science can increase the chances to discover and/or optimize URAT1 inhibitors, contributing to the development of novel drug candidates.

Considerations for Choosing First-Line Urate-Lowering Treatment in Older Patients with Comorbid Conditions

Gout is the most common inflammatory arthritis in adults. The prevalence of gout increases with age. Urate-lowering treatment (ULT) among older patients is often challenging in that patients frequently suffer insufficient effectiveness or adverse events due to comorbidities, concurrent medications, and altered pharmacokinetics. The large-scale randomized controlled trials (RCTs) directly investigating gout patients regarding cardiovascular (CV) safety have only recently been introduced; CARES and FAST compared the CV safety of the two xanthine oxidase inhibitors (XOis), febuxostat versus allopurinol, in patients with gout. Based on the CARES trial that showed CV concerns with febuxostat, the current international guidelines recommend allopurinol as first-line ULT in gout, while preserving other agents as a second-line treatment, despite a higher potency of febuxostat. XOis would be more suitable than uricosurics to treat older patients with gout due to the high prevalence of chronic kidney disease (CKD) in older patients. However, allopurinol alone might not achieve the target serum uric acid levels below 6 mg/dL and CKD might confer an increased risk of allopurinol induced cutaneous adverse reactions in older patients. Furthermore, as well as the later analysis of CARES participants who were lost to follow-up, data from the FAST trial and real-world studies suggest non-inferior CV safety for febuxostat compared to allopurinol even in the presence of CV diseases. Thus, febuxostat use in older patients with renal impairment may be more positively considered. The combination therapy of a novel uricosuric, verinurad, plus febuxostat reduced albuminuria in hyperuricemic patients with type 2 diabetes and CKD in a phase 2a trial, and further RCTs are awaited. Finally, the sodium-glucose cotransporter-2 inhibitor class of oral hypoglycemic agents, known to exert beneficial CV and renal effects independent of glycemic control, have shown a uricosuric effect and could be used as adjunctive therapy in older patients with cardiorenal comorbidities.

The role of gut microbiota in gout: Is gut microbiota a potential target for gout treatment

Numerous studies have demonstrated that gut microbiota is essential for the host's health because it regulates the host's metabolism, endocrine, and immune systems. In recent years, increasing evidence has shown that gut microbiota plays a role in the onset and progression of gout. Changes in the composition and metabolism of the gut microbiota, result in abnormalities of uric acid degradation, increasing uric acid generation, releasing pro-inflammatory mediators, and intestinal barrier damage in developing gout. As a result, gout therapy that targets gut microbiota has drawn significant interest. This review summarized how the gut microbiota contributes to the pathophysiology of gout and how gout affects the gut microbiota. Additionally, this study explained how gut microbiota might serve as a unique index for the diagnosis of gout and how conventional gout treatment medicines interact with it. Finally, prospective therapeutic approaches focusing on gut microbiota for the prevention and treatment of gout were highlighted, which may represent a future avenue in gout treatment.

Allopurinol blocks aortic aneurysm in a mouse model of Marfan syndrome via reducing aortic oxidative stress

BACKGROUND

Increasing evidence indicates that redox stress participates in MFS aortopathy, though its mechanistic contribution is little known. We reported elevated reactive oxygen species (ROS) formation and NADPH oxidase NOX4 upregulation in MFS patients and mouse aortae. Here we address the contribution of xanthine oxidoreductase (XOR), which catabolizes purines into uric acid and ROS in MFS aortopathy.

METHODS AND RESULTS

In aortic samples from MFS patients, XOR protein expression, revealed by immunohistochemistry, increased in both the tunicae intima and media of the dilated zone. In MFS mice (Fbn1^C1041G/+), aortic XOR mRNA transcripts and enzymatic activity of the oxidase form (XO) were augmented in the aorta of 3-month-old mice but not in older animals. The administration of the XOR inhibitor allopurinol (ALO) halted the progression of aortic root aneurysm in MFS mice. ALO administrated before the onset of the aneurysm prevented its subsequent development. ALO also inhibited MFS-associated endothelial dysfunction as well as elastic fiber fragmentation, nuclear translocation of pNRF2 and increased 3'-nitrotyrosine levels, and collagen maturation remodeling, all occurring in the tunica media. ALO reduced the MFS-associated large aortic production of H₂O₂, and NOX4 and MMP2 transcriptional overexpression.

CONCLUSIONS

Allopurinol interferes in aortic aneurysm progression acting as a potent antioxidant. This study strengthens the concept that redox stress is an important determinant of aortic aneurysm formation and progression in MFS and warrants the evaluation of ALO therapy in MFS patients.

Cardiovascular risk of urate-lowering drugs: A study using the National Database of Health Insurance Claims and Specific Health Checkups of Japan

In the present study, we aimed to investigate the association between urate-lowering drugs and cardiovascular events, primarily focusing on the risk of febuxostat and topiroxostat when compared with allopurinol in Japan. We conducted an observational study with a cohort design using the National Database of Health Insurance Claims and Specific Health Checkups of Japan, including new urate-lowering drugs users between August 1, 2010, and March 31, 2018. Exposure and control groups were defined based on the first prescription of urate-lowering drugs as follows: febuxostat or topiroxostat for exposure groups, allopurinol for the control group, and benzbromarone for the secondary control group. The primary outcome was cardiovascular events, defined as a composite of acute coronary syndrome, cerebral infarction, and cerebral hemorrhage. Hazard ratios were estimated using a Cox proportional hazards model. The number of patients in each exposure and control group was 1,357,671 in the febuxostat group, 83,683 in the topiroxostat group, 1,273,211 in the allopurinol group, and 258,786 in the benzbromarone group. The adjusted hazard ratios for the cardiovascular risk were 0.97 (95% confidence interval [CI]: 0.95-0.98) for febuxostat and 0.84 (95% CI: 0.78-0.90) for topiroxostat groups. The benzbromarone group exhibited similar results. No increased cardiovascular risk was observed with febuxostat or topiroxostat when compared with allopurinol in patients with hyperuricemia in Japan. These results provide real-world evidence regarding the cardiovascular risk associated with urate-lowering drugs, indicating that no additional safety-related regulatory actions are warranted in Japan.

Cardiovascular outcomes in adults with hypertension with evening versus morning dosing of usual antihypertensives in the UK (TIME study): a prospective, randomised, open-label, blinded-endpoint clinical trial

BACKGROUND

Studies have suggested that evening dosing with antihypertensive therapy might have better outcomes than morning dosing. The Treatment in Morning versus Evening (TIME) study aimed to investigate whether evening dosing of usual antihypertensive medication improves major cardiovascular outcomes compared with morning dosing in patients with hypertension.

METHODS

The TIME study is a prospective, pragmatic, decentralised, parallel-group study in the UK, that recruited adults (aged ≥18 years) with hypertension and taking at least one antihypertensive medication. Eligible participants were randomly assigned (1:1), without restriction, stratification, or minimisation, to take all of their usual antihypertensive medications in either the morning (0600-1000 h) or in the evening (2000-0000 h). Participants were followed up for the composite primary endpoint of vascular death or hospitalisation for non-fatal myocardial infarction or non-fatal stroke. Endpoints were identified by participant report or record linkage to National Health Service datasets and were adjudicated by a committee masked to treatment allocation. The primary endpoint was assessed as the time to first occurrence of an event in the intention-to-treat population (ie, all participants randomly assigned to a treatment group). Safety was assessed in all participants who submitted at least one follow-up questionnaire. The study is registered with EudraCT (2011-001968-21) and ISRCTN (18157641), and is now complete.

FINDINGS

Between Dec 17, 2011, and June 5, 2018, 24 610 individuals were screened and 21 104 were randomly assigned to evening (n=10 503) or morning (n=10 601) dosing groups. Mean age at study entry was 65·1 years (SD 9·3); 12 136 (57·5%) participants were men; 8968 (42·5%) were women; 19 101 (90·5%) were White; 98 (0·5%) were Black, African, Caribbean, or Black British (ethnicity was not reported by 1637 [7·8%] participants); and 2725 (13·0%) had a previous cardiovascular disease. By the end of study follow-up (March 31, 2021), median follow-up was 5·2 years (IQR 4·9-5·7), and 529 (5·0%) of 10 503 participants assigned to evening treatment and 318 (3·0%) of 10 601 assigned to morning treatment had withdrawn from all follow-up. A primary endpoint event occurred in 362 (3·4%) participants assigned to evening treatment (0·69 events [95% CI 0·62-0·76] per 100 patient-years) and 390 (3·7%) assigned to morning treatment (0·72 events [95% CI 0·65-0·79] per 100 patient-years; unadjusted hazard ratio 0·95 [95% CI 0·83-1·10]; p=0·53). No safety concerns were identified.

INTERPRETATION

Evening dosing of usual antihypertensive medication was not different from morning dosing in terms of major cardiovascular outcomes. Patients can be advised that they can take their regular antihypertensive medications at a convenient time that minimises any undesirable effects.

FUNDING

British Heart Foundation.

Allopurinol versus usual care in UK patients with ischaemic heart disease (ALL-HEART): a multicentre, prospective, randomised, open-label, blinded-endpoint trial

BACKGROUND

Allopurinol is a urate-lowering therapy used to treat patients with gout. Previous studies have shown that allopurinol has positive effects on several cardiovascular parameters. The ALL-HEART study aimed to determine whether allopurinol therapy improves major cardiovascular outcomes in patients with ischaemic heart disease.

METHODS

ALL-HEART was a multicentre, prospective, randomised, open-label, blinded-endpoint trial done in 18 regional centres in England and Scotland, with patients recruited from 424 primary care practices. Eligible patients were aged 60 years or older, with ischaemic heart disease but no history of gout. Participants were randomly assigned (1:1), using a central web-based randomisation system accessed via a web-based application or an interactive voice response system, to receive oral allopurinol up-titrated to a dose of 600 mg daily (300 mg daily in participants with moderate renal impairment at baseline) or to continue usual care. The primary outcome was the composite cardiovascular endpoint of non-fatal myocardial infarction, non-fatal stroke, or cardiovascular death. The hazard ratio (allopurinol vs usual care) in a Cox proportional hazards model was assessed for superiority in a modified intention-to-treat analysis (excluding randomly assigned patients later found to have met one of the exclusion criteria). The safety analysis population included all patients in the modified intention-to-treat usual care group and those who took at least one dose of randomised medication in the allopurinol group. This study is registered with the EU Clinical Trials Register, EudraCT 2013-003559-39, and ISRCTN, ISRCTN32017426.

FINDINGS

Between Feb 7, 2014, and Oct 2, 2017, 5937 participants were enrolled and then randomly assigned to receive allopurinol or usual care. After exclusion of 216 patients after randomisation, 5721 participants (mean age 72·0 years [SD 6·8], 4321 [75·5%] males, and 5676 [99·2%] white) were included in the modified intention-to-treat population, with 2853 in the allopurinol group and 2868 in the usual care group. Mean follow-up time in the study was 4·8 years (1·5). There was no evidence of a difference between the randomised treatment groups in the rates of the primary endpoint. 314 (11·0%) participants in the allopurinol group (2·47 events per 100 patient-years) and 325 (11·3%) in the usual care group (2·37 events per 100 patient-years) had a primary endpoint (hazard ratio [HR] 1·04 [95% CI 0·89-1·21], p=0·65). 288 (10·1%) participants in the allopurinol group and 303 (10·6%) participants in the usual care group died from any cause (HR 1·02 [95% CI 0·87-1·20], p=0·77).

INTERPRETATION

In this large, randomised clinical trial in patients aged 60 years or older with ischaemic heart disease but no history of gout, there was no difference in the primary outcome of non-fatal myocardial infarction, non-fatal stroke, or cardiovascular death between participants randomised to allopurinol therapy and those randomised to usual care.

FUNDING

UK National Institute for Health and Care Research.

Cardiovascular safety of febuxostat and allopurinol in patients with gout: A meta-analysis

Background: Gout is a common disease and is usually treated with uric acid-lowering drugs (the most commonly used of which are febuxostat and allopurinol). However, the cardiovascular safety of febuxostat and allopurinol is still controversial. The purpose of our study is to evaluate the cardiovascular safety of the two drugs in patients with gout using one-stage and two-stage meta-analysis.

Methods: PubMed, Embase, CBM, CNKI, WanFang, Central, and VIP were searched from inception to 30 January 2022. Randomized controlled trials which evaluated the cardiovascular safety of febuxostat or allopurinol for treating patients with gout were included. Based on the Kaplan–Meier curves of the two studies, individual patient data (IPD) were extracted and reconstructed. We used time-varying risk ratios (RRs) to summarize time-to-event outcomes, and the RRs of MACE incidence, cardiovascular mortality, and all-cause mortality were calculated by a multi-level flexible hazard regression model in 1-stage meta-analyses. p values were calculated using a log-rank test. At the same time, using the reconstructed IPD, we performed 2-stage meta-analyses to inform the quantitative estimates of time-specific relative risks at the six time points (1 , 2, 3, 4, 5, and 6 years) based on a random-effects model.

Results: Two RCTs with 12,318 participants were included. In the incidence of major adverse cardiovascular events between the two regimens, there was no significant difference [RR = 0.99 (95% CI, 0.89–1.11), p = 0.87]; at the same time, there was no significant difference in cardiovascular mortality [RR = 1.17 (95% CI, 0.98–1.40),p = 0.08] or all-cause mortality [RR = 1.03 (95% CI, 0.91–1.17),p = 0.62]. In terms of 2-stage meta-analyses, there was no significant difference in any outcomes at any time point (moderate-to low-certainty evidence).

Conclusion: In patients without atherosclerotic disease, febuxostat likely has a similar cardiovascular profile to allopurinol. However, in patients with a history of cardiovascular disease, allopurinol treatment is associated with less cardiovascular mortality as compared with febuxostat.

Systematic Review Registration:https://www.crd.york.ac.uk/prospero/#loginpage, identifier PROSPERO, CRD42022325656.

Review of Urate-Lowering Therapeutics: From the Past to the Future

We reviewed all currently available ULT, as well as any medications in development using following databases: United States Food and Drug Administration (FDA), European Medicines Agency (EMA), Japanese Pharmaceutical and Medical Devices Agency (PMDA), and ClinicalTrials.gov. We identified a total of 36 drugs, including 10 approved drugs, 17 in clinical testing phases, and 9 in preclinical developmental phases. The 26 drugs currently undergoing testing and development include 5 xanthine oxidase inhibitors, 14 uricosurics, 6 recombinant uricases, and one with multiple urate-lowering mechanisms of action. Herein, we reviewed the benefit and risk of each drug summarizing currently available drugs. New trials of uricosuric agents are underway to develop the new indication. New drugs are going on to improve the potency of recombinant uricase and to develop the new route administration of such as oral formulation. This review will provide valuable information on the properties, indications, and limitations of ULTs.

Cardiovascular risk associated with allopurinol or benzbromarone treatment in patients with gout

Background:

In previous studies, cardiovascular (CV) risk was increased in patients with gout. The effects of uric acid–lowering therapy on CV risk in gout patients have been investigated in numerous studies; however, allopurinol and benzbromarone have rarely been compared.

Objectives:

To compare CV risk based on allopurinol and benzbromarone treatment in Korean gout patients.

Design:

A nationwide population-based retrospective cohort study.

Methods:

We used South Korea database of the Health Insurance Review and Assessment (HIRA) service to identify gout patients ⩾18 years of age who newly started allopurinol or benzbromarone between 2009 and 2015. The primary outcome of the study was the occurrence of a composite CV endpoint, which included coronary revascularization, hospitalization due to myocardial infarction, ischemic stroke, and transient ischemic attack. Cox proportional hazard regression analysis and Kaplan–Meier curves were used for analysis.

Results:

The study included 257,097 allopurinol initiators and 7868 benzbromarone initiators. Compared with allopurinol initiators, the adjusted hazard ratio (aHR) of the composite CV endpoint of benzbromarone initiators was 1.01 [95% confidence interval (CI): 0.83−1.21], which was not significantly different. The results did not change even when 1:3 propensity score matching was performed for baseline characteristics. In subgroup analysis of high-risk patients with CV disease, significant difference was not observed between allopurinol and benzbromarone initiators.

Conclusion:

In this study, significant difference was not found in CV risk between allopurinol and benzbromarone initiators. In the high-CV-risk group, the incidence of CV events did not differ between allopurinol and benzbromarone initiators.

Sex difference in heart failure risk associated with febuxostat and allopurinol in gout patients

Background

Gout or rapid reduction in serum uric acid level may increase the incidence of heart failure (HF). To compare the risk of HF between febuxostat and allopurinol in gout patients with coexisting cardiovascular (CV) diseases, the varying severity would be likely to confound the risk estimation. Gout and HF are both sex-related diseases, and the risk difference from the urate-lowering agents between women and men remains unknown.

Aims

To evaluate the HF hospitalisations risk of febuxostat and allopurinol in gout patients in real-world settings.

Methods

A population-based cohort enrolled patients with allopurinol or febuxostat initiation from 2011 to 2018. Participants were grouped into, without (low CV risk group) or with (high CV risk group) a history of recent major CV admission. The primary outcome was HF hospitalization. The secondary outcomes were composite CV events, all-cause mortality, and the cause of CV mortality. We used the ‘as-treated' analysis and Cox proportional hazards model after propensity score (PS) matching. Patients were further stratified into men and women to evaluate the gender differences.

Results

Febuxostat users had a significantly higher risk of HF hospitalization than allopurinol users in gout patients either with low CV risk [hazard ratio (HR) 1.39; 95% confidence interval (CI) 1.25–1.55] or high CV risk [HR 1.36; 95% CI 1.22–1.52]. Particularly, women with gout had a higher risk of HF hospitalization than men.

Conclusion

The HF hospitalization risk was highest in gout women with high CV risk and febuxostat use. Monitoring of HF is warranted in these patients.

Update on Hypertension Research in 2021

In 2021, 217 excellent manuscripts were published in Hypertension Research. Editorial teams greatly appreciate the authors' contribution to hypertension research progress. Here, our editorial members have summarized twelve topics from published work and discussed current topics in depth. We hope you enjoy our special feature, "Update on Hypertension Research in 2021".

A glance into the future of gout

Gout is characterized by monosodium urate (MSU) crystal deposits in and within joints. These deposits result from persistent hyperuricaemia and most typically lead to recurrent acute inflammatory episodes (gout flares). Even though some aspects of gout are well characterized, uncertainties remain; this upcoming decade should provide further insights into many of these uncertainties. Synovial fluid analysis allows for the identification of MSU crystals and unequivocal diagnosis. Non-invasive methods for diagnosis are being explored, such as Raman spectroscopy and imaging modalities. Both ultrasound and dual-energy computed tomography (DECT) allow the detection of MSU crystals; this not only provides a mean of diagnosis, but also has furthered gout knowledge defining the presence of a preclinical deposition in asymptomatic hyperuricaemia. Scientific consensus establishes the beginning of gout as the beginning of symptoms (usually the first flare), but the concept is currently under review. For effective long-term gout management, the main goal is to promote crystal dissolution treatment by reducing serum urate below 6 mg/dL (or 5 mg/dL if faster crystal dissolution is required). Current urate-lowering therapies' (ULTs) options are limited, with allopurinol and febuxostat being widely available, and probenecid, benzbromarone, and pegloticase available in some regions. New xanthine oxidase inhibitors and, especially, uricosurics inhibiting urate transporter URAT1 are under development; it is probable that the new decade will see a welcomed increase in the gout therapeutic armamentarium. Cardiovascular and renal comorbidities are common in gout patients. Studies determining whether optimal treatment of gout will positively impact these comorbidities are currently lacking, but will hopefully be forthcoming. Overall, the single change that will most impact gout management is greater uptake of international rheumatology society recommendations. Innovative strategies, such as nurse-led interventions based on these recommendations have recently demonstrated treatment success for people with gout.

Cardiovascular Risk after Kidney Transplantation: Causes and Current Approaches to a Relevant Burden

Background. Cardiovascular disease is a frequent complication after kidney transplantation and represents the leading cause of mortality in this population. Material and Methods. We searched for the relevant articles in the National Institutes of Health library of medicine, transplant, cardiologic and nephrological journals. Results. The pathogenesis of cardiovascular disease in kidney transplant is multifactorial. Apart from non-modifiable risk factors, such as age, gender, genetic predisposition and ethnicity, several traditional and non-traditional modifiable risk factors contribute to its development. Traditional factors, such as diabetes, hypertension and dyslipidemia, may be present before and may worsen after transplantation. Immunosuppressants and impaired graft function may strongly influence the exacerbation of these comorbidities. However, in the last years, several studies showed that many other cardiovascular risk factors may be involved in kidney transplantation, including hyperuricemia, inflammation, low klotho and elevated Fibroblast Growth Factor 23 levels, deficient levels of vitamin D, vascular calcifications, anemia and poor physical activity and quality of life. Conclusions. The timely and effective treatment of time-honored and recently discovered modifiable risk factors represent the basis of the prevention of cardiovascular complications in kidney transplantation. Reduction of cardiovascular risk can improve the life expectancy, the quality of life and the allograft function and survival.

Febuxostat increases ventricular arrhythmogenesis through calcium handling dysregulation in human induced pluripotent stem cell-derived cardiomyocytes

Febuxostat is a xanthine oxidase inhibitor used to reduce the formation of uric acid and prevent gout attacks. Previous studies have suggested that febuxostat was associated with a higher risk of cardiovascular events, including atrial fibrillation, compared with allopurinol, another anti-hyperuricemia drug. Whereas in our clinical practice, we identified two cases of febuxostat-associated ventricular tachycardia events. The proarrhythmogenic effects of febuxostat on human cardiomyocytes and underlined mechanisms remain poorly understood. In this study, we employed real time cell analysis (RTCA) and calcium transient to investigate the effects of febuxostat on the cytotoxicity and electrophysiology properties of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). Up to 10 μM febuxostat treatment did not show toxicity to cell viability. However, 48-hour febuxostat exposure generated dose-dependent increased irregular calcium transients and decreased calcium transient amplitude. Furthermore, RNA-seq analysis indicated that the MAPK signaling pathway was enriched in the febuxostat-treated group, especially the protein kinases JNK. Western blotting of three main protein kinases demonstrated that JNK activation is related to febuxostat-induced arrythmia rather than ERK or p38. The dysfunctional calcium dynamics of febuxostat-treated hiPSC-CMs could be ameliorated by SP600125, the inhibitor of JNK. In conclusion, our study demonstrated that febuxostat increases the predisposition to ventricular arrythmia by dysregulating calcium dynamics.

Mapping Knowledge Structure and Global Research Trends in Gout: A Bibliometric Analysis From 2001 to 2021

Background

The incidence and prevalence of gout have been steadily increasing globally, which has resulted in gout research attracting consistently increased attention. This study aimed to visualize the knowledge structure and research trends in gout research through bibliometrics to help understand the future development of basic and clinical research.

Methods

Articles and reviews on gout from 2001 to 2021 were extracted from the Web of Science Core Collection database. CiteSpace and VOSviewer software were used to visualize the knowledge network of countries, institutions, authors, references, and keywords in this field. SPSS and Microsoft Excel software were used for curve fitting and correlation analysis.

Results

A total of 3,259 articles and reviews were included. The number of publications about gout significantly increased yearly. Publications were mainly concentrated in North America, Europe, Oceania, and East Asia. The USA contributed most with 1,025 publications, followed by China and New Zealand. After adjusting for publications by population size and Gross Domestic Product (GDP), New Zealand ranked in the first place. GDP and international collaboration were significantly correlated with scientific productivity for gout research. University of Auckland and Professor Dalbeth Nicola were the most prolific institutions and influential authors, respectively. Rheumatology was the most productive journal for gout research. Gout research hotspots have shifted over time in the following order: clinical features, pathological mechanisms, complications, gouty arthritis, epidemiology, and dual-energy computed tomography to drug clinical trials, which can be observed from the keyword analysis and co-cited reference cluster analysis.

Conclusions

This study found that research on gout is flourishing. The development and experimentation of drugs for the prevention and treatment of gouty arthritis would be the focus of current research and developmental trends in future research.

Serum uric acid in patients with ST-segment elevation myocardial infarction: An innocent bystander or leading actor?

Elevated serum uric acid (SUA) levels have been associated with several cardiovascular risk factors and the progression of coronary artery disease. In the setting of acute myocardial infarction, increasing evidence suggests that high SUA levels could be related to adverse outcomes. Interestingly elevated SUA levels have been linked to endothelial dysfunction, inflammation and oxidative stress. The aim of this review is to discuss the potential negative effects of SUA in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention, analyzing the possible underlying pathophysiological mechanisms.

Current state and prospects of gout treatment in Korea

Effective management of gout includes the following: appropriate control of gout flares; lifestyle modifications; management of comorbidities; and long-term urate-lowering therapy (ULT) to prevent subsequent gout flares, structural joint damage, and shortening of life expectancy. In addition to traditional treatments for gout, novel therapies have been introduced in recent years. Indeed, new recommendations for the management of gout have been proposed by various international societies. Although effective and safe medications to treat gout have been available, management of the disease has continued to be suboptimal, with poor patient adherence to ULT and failure to reach serum urate target. This review outlines recent progress in gout management, mainly based on the latest published guidelines, and specifically provides an update on efficient strategies for implementing treatment, efficacy and safety of specific medications for gout, and cardiovascular outcomes of ULT. In particular, we reviewed gout management approaches that can be applied to a Korean population.

Effect modification by contextual factors of urate-lowering therapy on serum urate in people with gout: A systematic review with meta-regression analysis

OBJECTIVE

To synthesize evidence of the effect of contextual factors (CFs) on efficacy of urate-lowering therapy (ULT) on serum urate (SU) as outcome in gout patients.

METHODS

Randomised controlled trials (RCTs) from (updated) Cochrane reviews were the starting point. RCTs were included if they explored the role of any CF on efficacy of ULT on SU in gout patients. For CFs with sufficient data (i.e. ≥3 trials), a mixed-effects meta-regression analysis was performed with trial and comparison as random effects, whereas specific CFs were modelled as fixed factors.

RESULTS

Eight RCTs were included. Effect modification by CFs was explored for age, sex, race, renal function, cardiovascular comorbidity, tophi, thiazide-diuretic use, and previous ULT use. Crude data stratified by renal function were available for four trials (36 randomised comparisons), and suitable for meta-analysis. Pooled estimates revealed that gout patients with a normal, mildly-, or moderately impaired renal function were consistently more likely to achieve SU target with ULT compared to control. Among RCTs comparing ULT to placebo (30 comparisons), effects of ULT on achieving SU target were not statistically different for those with normal (OR:66.87;[11.39-392.75]) compared to mildly (OR:28.54;[5.11-159.46]) and moderately (OR:21.45;[3.20-143.64]) impaired renal function, but seemed lower in those with severely impaired (OR:9.13;[0.96-86.97]) renal function. Data were insufficient to draw conclusions on effect modification by other CFs.

CONCLUSION

Few RCTs report stratified analyses exploring the role of CFs. ULT seemed effective in reaching the SU target in all levels of renal function, though severely impaired renal function appeared to render a slight disadvantage.

Characterization of xanthine oxidase inhibitory activities of phenols from pickled radish with molecular simulation

•

The 2,6-Dihydroxyacetophenone (DHAP), 4-Hydroxyphenethyl alcohol (4-HPEA), and 4-Hydroxybenzaldehyde (HBA) in pickled radish showed a good affinity for xanthine oxidase (XOD) in the molecular docking results.

•

DHAP, 4-HPEA and HBA inhibit in vitro XOD enzymatic activity by affecting secondary structure and hydrophobic groups, IC₅₀ were: 1.24 ± 0.02 mM, 24.52 ± 0.8 mM, and 2.67 ± 0.9 µM, respectively.

•

DHAP, 4-HPEA and HBA reduce xanthine-induced high uric acid levels in BRL 3A cells by inhibiting XOD enzyme activity (p < 0.05).

Pickled radish is a general source of natural bioactive compounds that include phenols. Here, we used molecular docking, fluorescence quenching, circular dichroism spectroscopy and molecular dynamics simulations to identify potential inhibitors against xanthine oxidase from a library of pickled radish compounds. The most effective compounds were selected for validation through in vitro experiments including enzyme activity inhibition tests, and cell-based assays. Molecular docking results revealed that 2,6-Dihydroxyacetophenone, 4-Hydroxyphenethyl alcohol, and 4-Hydroxybenzaldehyde exhibited significant effects on xanthine oxidase inhibition. Three phenols have varying degrees of inhibition on xanthine oxidase, which is driven by hydrophobic interactions and hydrogen bonds and affects the secondary structure and hydrophobic homeostasis of xanthine oxidase. The stability of xanthine oxidase inhibition by three phenols was analyzed by molecular dynamics simulation. Finally, cellular experiments confirmed that three phenols reduced uric acid levels by inhibiting the xanthine oxidase enzyme activity of BRL 3A cells.

Increased risk of cardiovascular events and death in the initial phase after discontinuation of febuxostat or allopurinol: another story of the CARES trial

OBJECTIVES

The Cardiovascular Safety of Febuxostat or Allopurinol in Patients with Gout (CARES) trial suggested a higher risk of cardiovascular (CV) death from febuxostat than from allopurinol. However, a significant number of patients died after discontinuation of febuxostat or allopurinol. We investigated whether major adverse cardiovascular events (MACE) and CV death were increased because of discontinuation of febuxostat or allopurinol using the CARES trial data.

METHODS

We compared the MACE that occurred during administration and after discontinuation in the initial phase after discontinuation, and we compared the CV and non-CV mortality rates in the initial phase after discontinuation to determine the impact of discontinuation of febuxostat or allopurinol.

RESULTS

Among 6190 patients, the incidence rate per 100 person-years for MACE was 3.11 during administration and 6.71 after discontinuation. MACE was significantly increased after discontinuation compared with that during administration within 1 month (HR 7.40; 95% CI 5.38 to 10.17) and 6 months (HR 5.22; 95% CI 4.26 to 6.39). In the analysis excluding death induced by adverse events that occurred up to 1 day after the last medication, the CV mortality rate was higher than the non-CV mortality rate within 6 months (45.7% vs 27.9%, p=0.0001). In addition, changes in serum uric acid levels from baseline to the last measurement before discontinuation were significantly associated with higher MACE risk after drug discontinuation (HR 1.14; 95% CI 1.04 to 1.26).

CONCLUSIONS

MACE and CV death were increased in the initial stage after discontinuation of febuxostat or allopurinol in patients with gout.

Evaluation of Serum Urate Levels and the Clinical Manifestation of Gout with Cardiovascular Mortality from the CARES Trial

Objective

To investigate whether serum urate levels, number of gout flares, and tophi burden are related to death from cardiovascular (CV) causes after treatment with febuxostat or allopurinol in patients with gout from the Cardiovascular Safety of Febuxostat or Allopurinol in Patients With Gout and Cardiovascular Comorbidities (CARES) trial.

Methods

Patients were randomly assigned to receive febuxostat (40 mg or 80 mg once daily, according to serum urate levels at week 2) or allopurinol titrated in 100‐mg increments from 200–400 mg or 300–600 mg (with dose determined according to kidney function). Changes from baseline in serum urate level, gout flares, and tophus resolution were key exploratory efficacy parameters in the overall population and in subgroups of patients who died and those who did not die from a CV‐related cause. The latter subgroup included patients who died due to non‐CV causes and those who did not die due to any cause.

Results

Patients received treatment with febuxostat (n = 3,098) or allopurinol (n = 3,092) for a median follow‐up period of 32 months (for a maximum of 85 months). In the overall population, mean serum urate levels were lower in those receiving febuxostat compared with those receiving allopurinol at most study visits. There were no associations between serum urate levels and death from CV causes with febuxostat. The number of gout flares requiring treatment was higher within 1 year of treatment with febuxostat compared with allopurinol (mean incidence of gout flares per patient‐years of exposure 1.33 versus 1.20), but was comparable thereafter and decreased overall throughout the study period (mean incidence of gout flares per patient‐years of exposure 0.35 versus 0.34 after 1 year of treatment; overall mean incidence 0.68 versus 0.63) irrespective of whether the patient died from a CV‐related cause. Overall, 20.8% of patients had ≥1 tophus at baseline; tophus resolution rates were similar between treatment groups, with cumulative resolution rates of >50%.

Conclusion

In the CARES trial, febuxostat and allopurinol (≤600 mg doses) had comparable efficacy in patients with gout and CV disease, and there was no evidence of a relationship between death from CV causes and serum urate levels, number of gout flares, or tophus resolution among the patients receiving febuxostat.

Evaluation of supported self-management in gout (GoutSMART): a randomised controlled feasibility trial

BACKGROUND

Improved outcomes for patients with gout are associated with the control of urate levels; yet, less than 40% of patients in the UK are currently offered urate lowering therapy, and it is typically offered without titration to target. Supported self-management has been shown to benefit patients with chronic health conditions; therefore, we aimed to determine whether a supported gout self-management approach, incorporating treatment-to-target urate, helped participants reach target urate levels.

METHODS

In this randomised controlled feasibility study, conducted in one hospital in Edinburgh, UK, we included patients (aged ≥18 years) with gout and a physician recommendation for initiation or escalation of urate lowering therapy. We randomised participants in a 2:1 ratio to a supported self-management group or a usual care group using the GoutSMART smartphone app. Participants in the self-management group were given a urate self-testing meter and received direct advice from clinicians on escalation of urate lowering therapy through the app. Participants were identified following referral to rheumatology, or using the Scottish Health Research Register, and they were screened and offered a detailed management plan before randomisation. Participants in the usual care group had a limited version of the app, which only allowed it to function as a health diary, and their gout management plan was implemented by their general practitioner. The primary outcome was the percentage of participants achieving a urate target of 0·30 mmol/L or less at 24 weeks, and analysis was by intent to treat. The trial was registered with ClinicalTrials.gov, NCT03274063, and there is an extension study ongoing. There was no masking of participants or assessors.

FINDINGS

Between April 5, 2019, and March 19, 2020, 60 (65%) of 92 patients screened were enrolled to the study. The mean age was 52.8 years (SD 14.6); 56 (93%) of the participants were male, and 4 (7%) were female. 58 (97%) of participants were White. 40 participants were assigned to the self-supported management group and 20 participants were assigned to the usual care group. A urate target of 0·30 mmol/L or less at 24 weeks was reached by 29 (73%) participants in the supported self-management group compared with 3 (15%) participants in the usual care group (risk difference 0·58 [95% CI 0·37-0·78]; p<0·0001). 90% of participants completed the study with no difference in the drop-out rate or adverse events between the two groups.

INTERPRETATION

Supported self-management of gout results in substantially improved attainment of urate targets compared with usual care, and it is well tolerated. Larger trials will be needed to fully evaluate the clinical and cost-effectiveness of this approach.

FUNDING

Edinburgh & Lothians Health Foundation.

Efficacy of Xanthine Oxidase Inhibitors in Lowering Serum Uric Acid in Chronic Kidney Disease: A Systematic Review and Meta-Analysis

Objective: Current guidelines for gout recommend a treat-to-target approach with serum uric acid (SUA). However, there is little evidence for the dose-dependent effects of urate-lowering therapy (ULT). Herein, we analyzed the reported SUA-lowering effect and SUA target achievement differences for various doses of xanthine oxidase inhibitors. Methods: Approved ULT drugs were selected from the FDA Drug Database. We included prospective randomized controlled trials of ULT drugs from ClinicalTrials.gov, articles published in the journal “Drugs”, and Embase, a literature database. A meta-analysis was performed to determine the ability of different ULT drugs and doses to lower and maintain a target SUA < 6 mg/dL. Results: We identified 35 trials including 8172 patients with a baseline SUA of 8.92 mg/dL. The allopurinol, febuxostat, and topiroxostat showed dose-proportional SUA-lowering responses. Compared with allopurinol 300 mg daily, febuxostat 80 mg daily and 120 mg daily more effectively maintained SUA < 6 mg/dL. Conclusion: Allopurinol, febuxostat, and topiroxostat showed dose-proportional ability to lower and achieve a target SUA < 6 mg/dL. Significance and Innovations. We showed dose-dependent SUA lowering effects of allopurinol, febuxostat, and topiroxostat. Febuxostat is effective at ULT compared to allopurinol and could be potentially offered as an alternative agent when patients (1) have CKD, (2) have the human leukocyte antigen HLA-B*5801 allele, and (3) become refractory to allopurinol. Gradual allopurinol dose increase with a lower starting dose is needed in CKD.