Febuxostat compared with allopurinol in patients with hyperuricemia and gout

Ameliorative action of "daitongxiao" against hyperuricemia includes the "uric acid transporter group"

This study aimed to investigate the potential mechanisms involved in the therapeutic effects of daitongxiao (DTX) on hyperuricemia (HUA). DTX was administered to two animal models of HUA via gavage feeding: HUA quail model (a uricotelic animal with urate oxidase deficiency), treated continuously for 35 days post-HUA induction, and HUA rats (an animal with active urate oxidase), treated continuously for 28 days post-HUA induction. HUA was induced in quail by administering a solution of sterile dry yeast powder via gavage feeding, while in rats, it was induced by intragastric gavage feeding of a solution of adenine and ethambutol hydrochloride. DTX improved overall health; increased bodyweight; reduced renal index, serum urate levels, serum xanthine oxidase activity, blood urea nitrogen, and creatinine; and enhanced urinary and fecal uric acid (UA) excretion in these two animal models. The results of hematoxylin and eosin and hexamine silver staining of kidney sections revealed that DTX significantly mitigated HUA-induced renal structural damage and inflammatory response. The results of quantitative real-time polymerase chain reaction, Western blotting, and immunofluorescence analyses revealed that DTX downregulated the renal expression levels of glucose transporter 9 (GLUT9) and upregulated the renal expression levels of organic anion transporters (OAT1 and OAT3) in both HUA models. Thus, the findings of this study suggest that DTX suppresses the progression of HUA by modulating the expression of the UA transporter group members.

Comparison of Gout Flares With the Initiation of Treat-to-Target Allopurinol and Febuxostat: A Post-Hoc Analysis of a Randomized Multicenter Trial

OBJECTIVE

Initiating urate-lowering therapy (ULT) in gout can precipitate arthritis flares. There have been limited comparisons of flare risk during the initiation and escalation of allopurinol and febuxostat, administered as a treat-to-target strategy with optimal anti-inflammatory prophylaxis.

METHODS

This was a post-hoc analysis of a 72-week randomized, double-blind, placebo-controlled, noninferiority trial comparing the efficacy of allopurinol and febuxostat. For this analysis, the occurrence of flares was examined during weeks 0 to 24 when ULT was initiated and titrated to a serum urate (sUA) goal of less than 6 mg/dl (<5 mg/dl if tophi). Flares were assessed at regular intervals through structured participant interviews. Predictors of flare, including treatment assignment, were examined using multivariable Cox proportional hazards regression.

RESULTS

Study participants (n = 940) were predominantly male (98.4%) and had a mean age of 62.1 years with approximately equal proportions receiving allopurinol or febuxostat. Mean baseline sUA was 8.5 mg/dl and all participants received anti-inflammatory prophylaxis (90% colchicine). In a multivariable model, there were no significant associations of ULT treatment (hazard ratio [HR] 1.17; febuxostat vs allopurinol), ULT-dose escalation (HR 1.18 vs no escalation), prophylaxis type, or individual comorbidity with flare and no evidence of ULT-dose escalation interaction. Factors independently associated with flare risk during ULT initiation/escalation included younger age, higher baseline sUA, and absence of tophi.

CONCLUSION

These results demonstrate that gout flare risk during the initiation and titration of allopurinol is similar to febuxostat when these agents are administered according to a treat-to-target strategy using gradual ULT-dose titration and best practice gout flare prophylaxis.

Efficacy and Safety of Allopurinol and Febuxostat in Patients With Gout and CKD: Subgroup Analysis of the STOP Gout Trial

RATIONALE & OBJECTIVE

We conducted a prespecified examination of the efficacy and safety of allopurinol and febuxostat administered using a treat-to-target strategy in trial participants with chronic kidney disease (CKD).

STUDY DESIGN

Prespecified sub cohort analysis of a randomized controlled trial.

SETTING

& Participants: A sub study of the STOP Gout trial in participants with CKD. CKD was defined as an eGFR 30-59 mL/min/1.73 m2 at baseline.

EXPOSURE

Trial participants with CKD and gout and serum urate (sUA) concentration ≥6.8 mg/dL were randomized 1:1 to receive allopurinol or febuxostat. Urate lowering therapy (ULT) was titrated during weeks 0-24 to achieve a goal sUA of <6.0 mg/dl (<5.0 mg/dl with tophi) (Phase 1) and maintained during weeks 25-48 (Phase 2). Gout flare was assessed between weeks 49-72 (Phase 3).

OUTCOME

Gout flare between weeks 49-72 (Phase 3) was the primary outcome. Secondary outcomes included sUA goal achievement and ULT dosing at end of Phase 2, and serious adverse events (SAEs).

ANALYTICAL APPROACH

Outcomes between treatment groups were compared using logistic regression models for binary outcomes, and Poisson regression for flare rates. Multivariable models were subsequently used, adjusting for factors identified to be imbalanced by treatment arm.

RESULTS

351 of 940 participants (37.3%) had CKD; 277 were assessed for the primary outcome. Fewer patients randomized to allopurinol had a flare during phase 3 (32% vs 45%; p=0.02) despite similar attainment of sUA goal (79% vs. 81%; p=0.6) by the end of Phase 2. Acute kidney injury (AKI) was more common in participants with stage 3 CKD randomized to allopurinol compared to febuxostat.

LIMITATIONS

Limited power to assess infrequent safety events, largely male, older population.

CONCLUSIONS

Allopurinol and febuxostat are similarly efficacious and well-tolerated in the treatment of gout in people with CKD when used in a treat-to-target regimen.

Comparative Risk of Gout Flares When Initiating or Escalating Various Urate-Lowering Therapy: A Systematic Review With Network Meta-Analysis

OBJECTIVE

We systematically examined comparative gout flare risk after initiation or escalation of different urate-lowering therapies (ULTs), comparative flare risk with and without concomitant flare prophylaxis, adverse event rates associated with flare prophylaxis, and optimal duration of flare prophylaxis.

METHODS

We searched the Medline, Embase, Web of Science, and Cochrane databases and clinical trial registries from inception to November 2021 for trials investigating adults with gout initiating or escalating ULT. We performed random effects network meta-analyses and calculated risk ratios (RRs) between treatments. Bias was assessed using the revised Cochrane risk-of-bias tool.

RESULTS

We identified 3,775 records, of which 29 publications (27 trials) were included. When compared to placebo plus prophylaxis, the RR of flares ranged from 1.08 (95% confidence interval [CI] 0.87-1.33) for febuxostat 40 mg plus prophylaxis to RR 2.65 [95% CI 1.58-4.45] for febuxostat 80 mg plus lesinurad 400 mg plus prophylaxis. Compared to ULT alone, the RR of flares was lower for ULT plus rilonacept 160 mg (RR 0.35 [95% CI 0.25-0.50]), ULT plus rilonacept 80 mg (RR 0.43 [95% CI 0.31-0.60]) and ULT plus colchicine (RR 0.50 [95% CI 0.35-0.72]). There was limited evidence for other flare prophylaxis and on prophylaxis harms and optimal duration. Primarily because of missing outcome data and bias in the selection of reported results, 71.4% and 63.4% of studies were assessed as high risk of bias for flares and adverse events, respectively.

CONCLUSION

The RR of flares when introducing ULT varies depending on ULT drug and dosing strategies. There were limited data on ULT escalation. Flare prophylaxis with colchicine and rilonacept reduces flare incidence. More research is required on the harms and optimal duration of prophylaxis.

Predicting Gout Flares in People Starting Allopurinol Using the Start-Low Go-Slow Dose Escalation Strategy

OBJECTIVE

The study objective was to determine predictors of gout flare when commencing allopurinol using the "start-low go-slow" dose escalation strategy.

METHODS

A post hoc analysis of a 12-month double-blind placebo-controlled noninferiority trial with participants randomized 1:1 to colchicine 0.5 mg daily or placebo for the first six months was undertaken. Multivariate logistic regression models were used to identify independent predictors of gout flares in the first and last six months of the trial.

RESULTS

Multivariable analysis revealed a significant association between risk of a gout flare in the first six months and flare in the month before starting allopurinol (odds ratio [OR] 2.65, 95% confidence interval [CI] 1.36-5.17) and allopurinol 100 mg starting dose (OR 3.21, 95% CI 1.41-7.27). The predictors of any gout flares in the last six months of the trial, after stopping colchicine or placebo, were having received colchicine (OR 2.95, 95% CI 1.48-5.86), at least one flare in the month before stopping study drug (OR 5.39, 95% CI 2.21-13.15), and serum urate ≥0.36 mmol/L at month 6 (OR 2.85, 95% CI 1.14-7.12).

CONCLUSION

Anti-inflammatory prophylaxis when starting allopurinol using the "start-low go-slow" dose escalation strategy may be best targeted at those who have had a gout flare in the month before starting allopurinol and are commencing allopurinol 100 mg daily. For those with ongoing gout flares during the first six months of starting allopurinol who have not yet achieved serum urate target, a longer period of prophylaxis may be required.

Hyperuricemia and intravenous fat emulsion are risk factors for gout flares during active gastrointestinal bleeding: a case control study

OBJECTIVE

It is well-established that patients with a history of gout are more susceptible to experiencing gastrointestinal bleeding. Gout flare during active gastrointestinal bleeding poses a significant challenge due to the gastrointestinal side effects of anti-inflammatory therapy. This study sought to investigate the risk factors associated with gout flares during episodes of gastrointestinal bleeding.

METHODS

We conducted a retrospective observational study involving 94 patients who experienced active gastrointestinal bleeding and had a history of gout. This study was conducted at Jinhua Municipal Central Hospital from January 2019 to October 2022. We collected and recorded demographic information and clinical characteristics.

RESULTS

Among the gout flare patients, hyperuricemia and intravenous fat emulsion therapy were more prevalent compared to those who remained stable (81.6% vs. 57.8% and 46.9% vs. 24.4%, p < 0.05). Multivariate logistic regression analysis revealed that both hyperuricemia (odds ratio 2.741, 95% CI 1.014-7.413, p = 0.047) and intravenous fat emulsion therapy (odds ratio 2.645, 95% CI 1.046-6.686, p = 0.040) were independent predictors of gout flares. Furthermore, gout attacks occurred sooner in patients receiving intravenous fat emulsion therapy compared to those not receiving it (median: 4 days (interquartile range: 2) vs. median: 5 days (interquartile range: 2.25), p = 0.049).

CONCLUSION

Our study revealed a high incidence of gout flares during episodes of active gastrointestinal bleeding, with patients undergoing intravenous fat emulsion therapy and those with hyperuricemia being at increased risk.

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

Key Points

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

Background

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

Methods

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

Results

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

Conclusions

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

Clinical Trial registry name and registration number:

SAPPHIRE Trial registration number, NCT03990363 .

Predictors of Inadequate Serum Urate Response to Low-Dose Febuxostat in Male Patients with Gout

Objective

This study aimed to understand predictors of inadequate response (IR) to low-dose febuxostat treatment based on clinical variables.

Methods

We pooled data from 340 patients of an observational cohort and two clinical trials who received febuxostat 20 mg/day for at least 3 months. IR was defined as failure to reach the target serum urate level (sUA<6 mg/dL) at any time point during 3 months treatment. The potential predictors associated with short- or mid-term febuxostat IR after pooling the three cohorts were explored using mixed-effect logistic analysis. Machine learning models were performed to evaluate the predictors for IR using the pooled data as the discovery set and validated in an external test set.

Results

Of the 340 patients, 68.9% and 51.8% were non-responders to low-dose febuxostat during short- and mid-term follow-up, respectively. Serum urate and triglyceride (TG) levels were significantly associated with febuxostat IR, but were also selected as significant features by LASSO analysis combined with age, BMI, and C-reactive protein (CRP). These five features in combination, using the best-performing stochastic gradient descent classifier, achieved an area under the receiver operating characteristic curve of 0.873 (95% CI [0.763, 0.942]) and 0.706 (95% CI [0.636, 0.727]) in the internal and external test sets, respectively, to predict febuxostat IR.

Conclusion

Response to low-dose febuxostat is associated with early sUA improvement in individual patients, as well as patient age, BMI, and levels of TG and CRP.

Uric acid-lowering effect of harpagoside and its protective effect against hyperuricemia-induced renal injury in mice

Hyperuricemia (HUA) is caused by increased synthesis and/or insufficient excretion of uric acid (UA). Long-lasting HUA may lead to a number of diseases including gout and kidney injury. Harpagoside (Harp) is a bioactive compound with potent anti-inflammatory activity from the roots of Scrophularia ningpoensis. Nevertheless, its potential effect on HUA was not reported. The anti-HUA and nephroprotective effects of Harp on HUA mice were assessed by biochemical and histological analysis. The proteins responsible for UA production and transportation were investigated to figure out its anti-HUA mechanism, while proteins related to NF-κB/NLRP3 pathway were evaluated to reveal its nephroprotective mechanism. The safety was evaluated by testing its effect on body weight and organ coefficients. The results showed that Harp significantly reduced the SUA level and protected the kidney against HUA-induced injury but had no negative effect on safety. Mechanistically, Harp significantly reduced UA production by acting as inhibitors of xanthine oxidase (XOD) and adenosine deaminase (ADA) and decreased UA excretion by acting as activators of ABCG2, OAT1 and inhibitors of GLUT9 and URAT1. Moreover, Harp markedly reduced infiltration of inflammatory cells and down-regulated expressions of TNF-α, NF-κB, NLRP3 and IL-1β in the kidney. Harp was a promising anti-HUA agent.

Moving urate-lowering therapy in gout beyond guideline recommendations

The 'treat-to target serum urate strategy' when using urate-lowering therapy has been recommended by most specialist rheumatology societies for many years. An alternative "treat-to-avoid-symptoms" in gout has been suggested, albeit without a clear definition of what this means and how it might be implemented in clinical trials or clinical practice. This has hampered efforts to design clinical trials that compare the "treat-to-target [urate]" and "treat-to-avoid-symptoms" strategies in the long-term management of gout. In this review we consider the rationale for the treat-to-target urate strategy when using urate-lowering therapy, potential definitions of a "treat-to-avoid-symptoms" strategy, or perhaps what is not "treat-to-avoid-symptoms", and approaches that might address this uncertainty.

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

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

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

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

A content analysis of medication adherence material in patient educational resources about gout

Objective

This study aimed to investigate how medication adherence is addressed in online gout resources in six countries. We investigated how often adherence was referred to, the strategies suggested to improve patient adherence, and the types of nonadherence that were targeted. We also examined the readability of the adherence material.

Methods

A content analysis was conducted on 151 online gout resources from medical and health organisations in six predominantly English-speaking countries. Two reviewers coded the content of the websites into categories (kappa 0.80). The analysis involved coding the resources for reasons for nonadherence, and adherence-promoting strategies. Flesch-Kincaid Reading Ease scores and word count were also computed.

Results

Out of 151 websites examined, 77 websites discussed medication adherence (51%), with intentional nonadherence being more prevalent than unintentional nonadherence. 67 websites targeted different types of nonadherence, including drug-specific concerns (50%), misconceptions of gout curability and the necessity of medication (16%), forgetfulness (16%), and other practical challenges (5%). Strategies to promote adherence were found in one-third of the websites, with medication education being the most prevalent strategy (17%), followed by healthcare provider engagement (13%) and memory aid strategies (6%). On average, about 11% of the words (89.27, SD = 76.35) in the entire document were focused on adherence. Difficult reading comprehension was found in one-fifth of adherence-related websites.

Conclusion

Findings reveal limited medication adherence coverage and narrow strategies in online gout resources. Improved adherence portrayal is needed for effective gout management through comprehensive strategies and clear, understandable information.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Febuxostat dose requirement according to renal function in patients who achieve target serum urate levels: A retrospective cohort study

OBJECTIVES

To determine the febuxostat dose requirement according to renal function in patients who achieve target serum urate (SU) levels.

METHODS

Of 3153 gout patients who underwent febuxostat treatment, 873 patients with an initial SU level>6mg/dL were included and categorized by the estimated glomerular filtration rate: normal, chronic kidney disease (CKD) stage 3, and stages 4-5. Ninety-five patients with insufficient follow-up were further excluded. The dose of febuxostat in patients who achieved the SU target (< 6mg/dL) was defined as the average daily dosage at the time of SU target achievement.

RESULTS

The cohort of 778 gout patients had a median age of 52.0 years (IQR, 41.0-63.0) and comprised 711 (91.4%) men. The mean SU at febuxostat initiation was higher in the CKD 4-5 (9.6 [± 3.1] mg/dL) than in the other groups (CKD 3, 8.7 [± 1.7]; normal, 8.4 [± 1.7]; P<0.001). Patients achieved target SU at a median of 4.0 (1.9-9.6) months and in those who achieved target SU, the dose of febuxostat at the time of SU target achievement was significantly lower in the CKD 4-5 group (50.0 [± 16.5] mg) than in the other groups (vs. CKD stage 3, 60.0 [± 19.5] mg; P<0.01, vs. normal, 60.0 [± 19.8] mg; P<0.01). Furthermore, CKD stage 4-5 had a negative correlation with the febuxostat dose requirement (Beta: -2.334, P<0.05).

CONCLUSION

Among patients who achieved SU target, those with severely decreased renal function (CKD 4-5) required a lower febuxostat dose to achieve the target SU level compared to patients with normal or mild renal impairment.

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

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

Efficacy of dotinurad in patients with severe renal dysfunction

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Cardiovascular safety of febuxostat versus allopurinol among the Asian patients with or without gout: A systematic review and meta-analysis

The cardiovascular (CV) safety of febuxostat compared to allopurinol for the treatment of hyperuricemia among Asian patients is uncertain. In this study, we conducted a systematic review and meta-analysis to compare the CV safety profiles of febuxostat with allopurinol in Asian patients with hyperuricemia. A total of 13 studies were included. On the basis of the pooled results of cohort studies, febuxostat users were at a significantly higher risk for acute coronary syndrome (ACS; hazard ratio [HR]: 1.06, 95% confidence interval [CI]: 1.03-1.09, p < 0.01), atrial fibrillation (HR: 1.19, 95% CI: 1.05-1.35, p < 0.01) than allopurinol users, whereas no significant difference between febuxostat and allopurinol existed for urgent coronary revascularization (HR: 1.07, 95% CI: 0.98-1.16, p = 0.13), and stroke (HR: 0.96, 95% CI: 0.91-1.01, p = 0.13). Nevertheless, that difference in results of acute decompensated heart failure (ADHF; HR: 0.73, 95% CI: 0.35-1.53, p = 0.40) and all-cause death (HR = 0.86, 95% CI: 0.49-1.51, p = 0.60) was not significant based on randomized controlled trials. In the Chinese subgroup, febuxostat could increase the risk of ADHF (HR: 1.22, 95% CI: 1.01-1.48, p < 0.05), CV death (HR: 1.25, 95% CI: 1.03-1.50, p < 0.05), and all-cause mortality (HR: 1.07, 95% CI: 1.01-1.14, p < 0.05) compared to allopurinol. In conclusion, the use of febuxostat, compared with allopurinol among Asian patients, was associated with a significantly increased risk of adverse CV events.

Identification of inhibitors from a functional food-based plant Perillae Folium against hyperuricemia via metabolomics profiling, network pharmacology and all-atom molecular dynamics simulations

Introduction

Hyperuricemia (HUA) is a metabolic disorder caused by purine metabolism dysfunction in which the increasing purine levels can be partially attributed to seafood consumption. Perillae Folium (PF), a widely used plant in functional food, has been historically used to mitigate seafood-induced diseases. However, its efficacy against HUA and the underlying mechanism remain unclear.

Methods

A network pharmacology analysis was performed to identify candidate targets and potential mechanisms involved in PF treating HUA. The candidate targets were determined based on TCMSP, SwissTargetPrediction, Open Targets Platform, GeneCards, Comparative Toxicogenomics Database, and DrugBank. The potential mechanisms were predicted via Gene Ontology (GO) and Kyoto Gene and Genome Encyclopedia (KEGG) analyses. Molecular docking in AutoDock Vina and PyRx were performed to predict the binding affinity and pose between herbal compounds and HUA-related targets. A chemical structure analysis of PF compounds was performed using OSIRIS DataWarrior and ClassyFire. We then conducted virtual pharmacokinetic and toxicity screening to filter potential inhibitors. We further performed verifications of these inhibitors' roles in HUA through molecular dynamics (MD) simulations, text-mining, and untargeted metabolomics analysis.

Results

We obtained 8200 predicted binding results between 328 herbal compounds and 25 potential targets, and xanthine dehydrogenase (XDH) exhibited the highest average binding affinity. We screened out five promising ligands (scutellarein, benzyl alpha-D-mannopyranoside, elemol, diisobutyl phthalate, and (3R)-hydroxy-beta-ionone) and performed MD simulations up to 50 ns for XDH complexed to them. The scutellarein-XDH complex exhibited the most satisfactory stability. Furthermore, the text-mining study provided laboratory evidence of scutellarein's function. The metabolomics approach identified 543 compounds and confirmed the presence of scutellarein. Extending MD simulations to 200 ns further indicated the sustained impact of scutellarein on XDH structure.

Conclusion

Our study provides a computational and biomedical basis for PF treating HUA and fully elucidates scutellarein's great potential as an XDH inhibitor at the molecular level, holding promise for future drug design and development.

Anti-Hyperuricemic Effects of Extracts from Chaenomeles speciosa (Sweet) Nakai Fruits on Hyperuricemic Rats

Chaenomeles speciosa (Sweet) Nakai (C. speciosa) fruit has medicinal and food applications and exhibits beneficial pharmacological properties. This study aimed to explore the hypouricemic effect of C. speciosa fruit extracts on hyperuricemic rats and uncover potential protective mechanisms. The rats were given hypoxanthine (HX, 100 mg/kg) and potassium oxonate (PO, 300 mg/kg) for 14 days to induce hyperuricemia. Subsequently, the rats were orally administered C. speciosa fruits total extract (CSFTE, 250, 500, and 1000 mg/kg) and allopurinol (AP, 10 mg/kg) one hour after exposure to HX and PO. The results showed that CSFTE had significant xanthine oxidase (XOD) inhibitory activity in vitro (IC50 value of 334.2 μg/mL) and exhibited hypouricemic effects in vivo, reducing uric acid (UA), creatinine (CRE), and blood urea nitrogen (BUN) levels in serum. CSFTE increased UA excretion through the regulation of URAT1, GLUT9, OAT1, and OAT3 protein expression in the kidneys of hyperuricemic rats. Additionally, CSFTE (500 and 1000 mg/kg) was more effective than AP in improving renal injury and protecting kidney function in hyperuricemic rats. Our study demonstrated that CSFTE effectively reduced UA levels and protected the kidneys by inhibiting XOD expression in vitro and regulating UA, CRE, BUN, URAT1, GLUT9, OAT1, and OAT3 proteins in vivo.

Estimated excretion and clearance of uric acid as optimal surrogate indices for daily urinary uric acid excretion

OBJECTIVES

Daily uric acid excretion (Eua) is an essential index for patients with gout/hyperuricaemia. We identified alternative indices most correlated with 24-hour uric acid clearance (Cua 24 h) and 24-hour Eua (Eua 24 h) using data from the reference interval of urinary clearance and excretion of urate study.

METHODS

The subjects were indoor workers aged 20-65 years who met the Clinical and Laboratory Standards Institute Guidelines C28-A3c. Alternative indices using spot urine were urine uric acid creatinine ratio, Cua-creatinine clearance ratio (Cua/Ccr), Eua-CCr ratio (Eua/Ccr), estimated Cua (eCua), and estimated Eua (eEua). eCua and eEua are the values obtained by multiplying Cua/Ccr and Eua/Ccr with the estimated glomerular filtration rate.

RESULTS

The final number of subjects analysed was 739. Among the indices using spot urine, eCua and eEua showed the highest correlation with Cua 24 h and Eua 24 h, respectively. Compared with Cua 60 min and Eua 60 min obtained from 60-min urine collection, eCua and eEua showed lower root means squared error, lower bias, and significantly higher accuracy of within 30% and within 15%.

CONCLUSIONS

The newly proposed eCua and eEua may be appropriate from a practical perspective.

In vivo study of newly developed albumin-conjugated urate oxidase for gout treatment

BACKGROUND

Exogenously providing engineered Uox with enhanced half-life is one of the important urate-lowering treatments for gout. The potential of PAT101, a recombinant human albumin (rHA)-conjugated variant, was evaluated and compared as a novel gout treatment through various in vivo studies with PAT101 and competing drugs.

METHODS

PAT101 was produced by site-specific conjugation of rHA and Aspergillus flavus Uox (AfUox-rHA) through clickable non-natural amino acid (frTet) and Inverse electron demand Diels-Alder (IEDDA) reaction. In vivo pharmacokinetics, efficacy tests and in vitro immunogenetic assay were performed after single or multiple doses of PAT101 and its competitors in BALB/c mice, transgenic (TG) mice, Sprague-Dawley (SD) rats, and non-human primate (NHP).

RESULTS

The half-life of PAT101 in single-dose treated TG mice was more than doubled compared to pegloticase. In SD rats with 4 weeks of repeated administration of rasburicase, only 24% of Uox activity remained, whereas in PAT101, it was maintained by 86%. In the Uox KO model, the survival rate of PAT101 was comparable to that of pegloticase. In addition, human PBMC-based CD4+/CD8+ T-cell activation analysis demonstrated that PAT101 has a lower immune response compared to the original drug, rasburicase.

CONCLUSION

All results suggest that this rHA-conjugated AfUox, PAT101, can be provided as a reliable source of Uox for gout treatment.

Preparation of chitosan-coated hollow tin dioxide nanoparticles and their application in improving the oral bioavailability of febuxostat

The aim of this study was to design a chitosan-coated hollow tin dioxide nanosphere (CS-HSn) for loading febuxostat (FEB) using an adsorption method to obtain a sustained-release system (CS-HSn-FEB) to improve the oral bioavailability of FEB. The morphological characteristics of hollow tin dioxide nanospheres (HSn) and CS-HSn were analyzed by transmission electron microscopy (TEM) and dynamic light scattering (DLS). The hemolysis test and CCK-8 test were used to assess the biosafety of HSn and CS-HSn. Powder X-ray diffraction (PXRD) and differential scanning thermal analysis (DSC) were performed on CS-HSn-FEB to analyze the drug presence status. The dissolution behavior and changes in plasma drug concentration of CS-HSn-FEB were evaluated in vitro and in vivo. Sections of intestinal tissues from SD rats were obtained to observe whether chitosan could increase the distribution of nanoparticles in the intestinal tissues. The results showed that FEB was present in CS-HSn in an amorphous state. Moreover, CS-HSn, with good biosafety, significantly improved the water solubility and oral absorption of FEB, indicating that CS-HSn has great potential to improve the intestinal absorption and oral bioavailability of insoluble drugs.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Is colchicine prophylaxis required with start-low go-slow allopurinol dose escalation in gout? A non-inferiority randomised double-blind placebo-controlled trial

OBJECTIVES

To determine whether placebo is non-inferior to low-dose colchicine for reducing gout flares during the first 6 months of allopurinol using the 'start-low go-slow' dose approach.

METHODS

A 12-month double-blind, placebo-controlled non-inferiority trial was undertaken. Adults with at least one gout flare in the preceding 6 months, fulfilling the American College of Rheumatology (ACR) recommendations for starting urate-lowering therapy and serum urate ≥0.36 mmol/L were recruited. Participants were randomised 1:1 to colchicine 0.5 mg daily or placebo for the first 6 months. All participants commenced allopurinol, increasing monthly to achieve target urate <0.36 mmol/L. The primary efficacy outcome was the mean number of gout flares/month between 0 and 6 months, with a prespecified non-inferiority margin of 0.12 gout flares/month. The primary safety outcome was adverse events over the first 6 months.

RESULTS

Two hundred participants were randomised. The mean (95% CI) number of gout flares/month between baseline and month 6 was 0.61 (0.47 to 0.74) in the placebo group compared with 0.35 (0.22 to 0.49) in the colchicine group, mean difference 0.25 (0.07 to 0.44), non-inferiority p=0.92. There was no difference in the mean number of gout flares/month between randomised groups over the 12-month period (p=0.68). There were 11 serious adverse events in 7 participants receiving colchicine and 3 in 2 receiving placebo.

CONCLUSIONS

Placebo is not non-inferior to colchicine in prevention of gout flares in the first 6 months of starting allopurinol using the 'start-low go-slow' strategy. After stopping colchicine, gout flares rise with no difference in the mean number of gout flares/month between groups over a 12-month period.

TRIAL REGISTRATION NUMBER

ACTRN 12618001179224.

Past, present and future of xanthine oxidase inhibitors: design strategies, structural and pharmacological insights, patents and clinical trials

Xanthine oxidase, a molybdo-flavoenzyme, and an isoform of xanthine dehydrogenase both exist as xanthine oxidoreductase and are responsible for purine catabolism. Xanthine oxidase is more involved in pathological conditions when extensively modulated. Elevation of xanthine oxidase is not only the prime cause of gout but is also responsible for various hyperuricemia associated pathological conditions like diabetes, chronic wounds, cardiovascular disorders, Alzheimer's disease, etc. Currently available xanthine oxidase inhibitors in clinical practice (allopurinol, febuxostat and topiroxostat) suffer from fatal side effects that pose a serious problem to the healthcare system, raising global emergency to develop novel, potent and safer xanthine oxidase inhibitors. This review will provide key and systematic information about: a. design strategies (inspired from both marketed drugs in clinical practice and natural products), structural insights and pharmacological output (xanthine oxidase inhibition and associated activities) of various pre-clinical candidates reported by various research groups across the globe in the past two decades; b. patented xanthine oxidase inhibitors published in the last three decades and c. clinical trials and their outcomes on approved drug candidates. Information generated in this review has suggested fragment-based drug design (FBDD) and molecular hybridization techniques to be most suitable for development of desired xanthine oxidase inhibitors as one provides high selectivity toward the enzyme and the other imparts multifunctional properties to the structure and both may possess capabilities to surpass the limitations of currently available clinical drugs. All in combination will exclusively update researchers working on xanthine oxidase inhibitors and allied areas and potentially help in designing rational, novel, potent and safer xanthine oxidase inhibitors that can effectively tackle xanthine oxidase related disease conditions and disorders.

Efficacy of initiating urate-lowering therapy during an acute gout episode: a meta-analysis

OBJECTIVE

This study aimed to evaluate the effectiveness of initiating urate-lowering therapy (ULT) during acute gout episodes.

METHODS

We performed a literature search using MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials (from inception to February 2023). We conducted a comprehensive review and meta-analysis of randomized controlled trials (RCTs) that examined the efficacy of ULT in individuals with acute gout flares.

RESULTS

This review included six RCTs with 479 patients (225 experimental participants and 254 controls). The experimental group had longer days to resolution than did the control group. There was no significant difference in the pain visual analogue scale score between the groups by day 10. Erythrocyte sedimentation rate and C‑reactive protein level did not significantly differ between the groups by days 7 to 14. Both groups had similar rates of recurrent gout attacks by 30 days. There was no significant between-group difference in the dropout rate.

CONCLUSION

Initiating ULT therapy during a gout attack does not appear to increase the duration of the flare or aggravate pain. Despite these findings, further studies with larger sample sizes are necessary to support these conclusions.

The Stiff Joint: Comparative Evaluation of Monotherapy and Combination Therapy With Urate Lowering Agents in Managing Acute Gout

Gout, an extremely painful form of arthritis, is triggered by the innate immune system's response to the accumulation of monosodium urate crystals in specific joints and surrounding tissues. This condition is characterized by recurring episodes of excruciating arthritis flares, interspersed with periods of disease quiescence. Over time, gout can result in disability, tophi formation, and severe pain. The treatment of gout is centered around two main objectives: alleviating inflammation and pain during acute gout attacks and long-term management to reduce serum urate levels and mitigate the risk of future attacks. Addressing inflammation and pain during acute attacks is often complicated by various factors, including underlying health conditions commonly associated with gout, such as hypertension, chronic kidney disease, cardiovascular disease, and diabetes mellitus. Moreover, gout patients are frequently older and have multiple coexisting health issues, necessitating complex medication regimens. Given the rising prevalence of gout and its associated comorbidities, there's a growing demand for improved treatment options. While existing treatments effectively manage gout in some patients, a significant portion, particularly those with comorbidities, face contraindications to these treatments and require alternative approaches. Innovative medications are required to enhance gout treatment, especially for individuals with concurrent health conditions. These considerations underscore the importance of reviewing both monotherapy and combination therapy approaches for acute gout treatment.

Dose-response relationships of tea and coffee consumption with gout: a prospective cohort study in the UK Biobank

OBJECTIVES

The association of tea or coffee consumption with gout is inconsistently reported. Few prospective studies have explored their dose-response relationship. Therefore, we aimed to quantitatively investigate the association between tea, coffee and the risk of developing gout.

METHODS

The study included 447 658 participants in the UK Biobank who were initially free of gout. Tea and coffee consumption were assessed at baseline. We used Cox proportional hazards models to estimate the associations between tea/coffee consumption and incident gout, with restricted cubic spline added to the Cox models to evaluate the dose-response relationships.

RESULTS

During a median follow-up period of 13.42 years, we recorded 3,053 gout cases. The associations between tea, coffee and gout were nonlinear, with a significant reduction in the risk by ∼ six cups/day of tea and three cups/day of coffee. Compared with those who were not tea and coffee drinkers, those who consumed >6 cups/day of tea or coffee were associated with 23% (HR 0.77, 95% CI, 0.66, 0.91) and 40% (HR 0.60, 95% CI, 0.47, 0.77) lower risks of gout, respectively, and both caffeinated and decaffeinated coffee consumption were associated with a decreased risk. Moreover, hyperuricaemia may modify the association between coffee and gout. Compared with non-coffee consumers with hyperuricaemia, those with ≥4 cups/day coffee intake without hyperuricaemia had the lowest risk (HR 0.34, 95% CI, 0.28, 0.41).

CONCLUSION

Consumption of tea or coffee had a strong nonlinear association in gout risk reduction. Hyperuricaemia status had a potential effect modification on the association of coffee intake with gout.

Dispelling Dampness, Relieving Turbidity and Dredging Collaterals Decoction, Attenuates Potassium Oxonate-Induced Hyperuricemia in Rat Models

Purpose

Dispelling dampness, relieving turbidity and dredging collaterals decoction (DED), is a traditional Chinese medicine used in the treatment of hyperuricemia. We aimed to explore the effect and mechanism of DED in the treatment of hyperuricemia.

Methods

The effects of DED (9.48, 4.74, and 2.37 g/kg/d) on potassium oxonate (750 mg/kg/d)-induced hyperuricemia in rats were evaluated by serum uric acid (UA), creatinine (CRE), blood urea nitrogen (BUN), and renal pathological changes. Network pharmacology was used to identify the effective components and targets of DED, and the key targets and signaling pathways for its effects on hyperuricemia were screened. Molecular docking was used to predict the action of DED. H&E, immunohistochemistry, WB, and PCR were used to validate the network pharmacology results.

Results

DED can effectively alleviate hyperuricemia, inhibit UA, CRE, BUN, and xanthine oxidase (XOD) activity, and reduce renal inflammatory cell infiltration and glomerular atrophy. The experiment identified 27 potential targets of DED for hyperuricemia, involving 9 components: wogonin, stigmasterol 3-O-beta-D-glucopyranoside, 3β-acetoxyatractylone, beta-sitosterol, stigmasterol, diosgenin, naringenin, astilbin, and quercetin. DED can relieve hyperuricemia mainly by inhibiting RAGE, HMGB1, IL17R, and phospho-TAK1, and by regulating the AGE-RAGE and IL-17 signaling pathways.

Conclusion

DED can alleviate hyperuricemia by inhibiting XOD activity and suppressing renal cell apoptosis and inflammation via the AGE-RAGE signaling pathway and IL-17 signaling pathway. This study provides a theoretical basis for the clinical application of DED.

Gout Flares and Mortality After Sodium-Glucose Cotransporter-2 Inhibitor Treatment for Gout and Type 2 Diabetes

Importance

Recurrent flares are the hallmark of clinical manifestation of gout. Sodium-glucose cotransporter-2 inhibitors (SGLT2i) have been associated with a lower risk of incident gout; however, their association with recurrent flares is unknown.

Objective

To examine the association of SGLT2i vs active comparators (ie, glucagonlike peptide-1 receptor agonists [GLP-1 RA] or dipeptidyl peptidase-4 inhibitors [DPP-4i]) with the risk of recurrent gout flares and all-cause mortality among patients with gout and type 2 diabetes.

Design, Setting, and Participants

This population-based retrospective cohort study was performed from January 1, 2013, to March 31, 2022, using a UK primary care database. Participants included patients with gout and type 2 diabetes with visits to their general practitioners.

Exposures

Initiation of treatment with SGLT2i or active comparators.

Main Outcomes and Measures

The primary outcome was the number of recurrent gout flares ascertained using recorded codes and prescription records. Secondary outcomes were the first recurrent gout flare and all-cause mortality. The association of SGLT2i compared with active comparators for the risk of recurrent flares, the first recurrent flare, and all-cause mortality was assessed using Poisson regression or the Cox proportional hazards model with propensity score overlap weighting.

Results

Of a total of 5931 patients included in the analysis (mean [SD] age, 66.0 [11.6] years; 4604 [77.6%] men), 1548 initiated SGLT2i treatment and 4383 initiated treatment with active comparators during the study period. The relative rate of the recurrent flares with SGLT2i vs active comparators was 0.79 (95% CI, 0.65-0.97). Similar results were observed in the association of SGLT2i with the rate of recurrent flares when compared with DPP-4i or GLP-1 RA. For the first recurrent flare for SGLT2i vs active comparators, rate difference was -8.8 (95% CI, -17.2 to -0.4) per 1000 person-years and the hazard ratio was 0.81 (95% CI, 0.65-0.98). All-cause mortality per 1000 person-years was 18.8 for SGLT2i and 24.9 for active comparators, with rate difference of -6.1 (95% CI, -10.6 to -1.6) per 1000 person-years and hazard ratio of 0.71 (95% CI, 0.52-0.97).

Conclusions and Relevance

The findings of this cohort study suggest that SGLT2i were associated with a lower risk of recurrent gout flares and mortality than their active comparators in patients with gout and type 2 diabetes. These findings further suggest that SGLT2i could help reduce the burden of recurrent gout flares and could also narrow the mortality gap between patients with gout and the general population.

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.

Effect of Febuxostat versus Allopurinol on the Glomerular Filtration Rate and Hyperuricemia in Patients with Chronic Kidney Disease

Hyperuricemia is a risk factor for the progression of chronic kidney disease (CKD). We compared febuxostat versus allopurinol in the progression of CKD and hyperuricemia in 101 patients with Stage 3-4 CKD treated with febuxostat or allopurinol for at least 6 months for hyperuricemia (>7 mg/dL) between January 2012 and December 2016. Baseline characteristics, serum uric acid (SUA), serum creatinine, and estimated glomerular filtration rate (eGFR) at entry and 6 months were compared. The primary outcome was the decline in eGFR and the secondary outcomes were reductions in SUA and adverse events. Fifty-four were in the febuxostat group and 47 were in the allopurinol group. The baseline characteristics were comparable except for age. The mean dose of febuxostat and allopurinol was 43.70 ± 14.5 mg and 108.51 ± 40 mg, respectively. After 6 months, the median rate of decline in eGFR was 1.2 mL/min/1.73 m2 (IQR: 1.2, 5.5) in the febuxostat group and 3.1 mL/min/1.73 m2 (0.6, 6.2) in the allopurinol group, but this was not statistically significant (P = 0.136). The mean reduction in SUA was significantly better (P = 0.004) in the febuxostat group (3.9 ± 1.7 mg/dL) compared with the allopurinol group (2.1 ± 1.0 mg/dL). Both drugs had no serious adverse events. Febuxostat was better at reducing hyperuricemia than allopurinol, but there was no significant difference in the progression of CKD. Large randomized trials and long-term follow-up are necessary to see whether febuxostat has a favorable effect on the progression of CKD.

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.

Computational Characterization of the Inhibition Mechanism of Xanthine Oxidoreductase by Topiroxostat

Xanthine oxidase (XO) is a member of the molybdopterin-containing enzyme family. It interconverts xanthine to uric acid as the last step of purine catabolism in the human body. The high uric acid concentration in the blood directly leads to human diseases like gout and hyperuricemia. Therefore, drugs that inhibit the biosynthesis of uric acid by human XO have been clinically used for many years to decrease the concentration of uric acid in the blood. In this study, the inhibition mechanism of XO and a new promising drug, topiroxostat (code: FYX-051), is investigated by employing molecular dynamics (MD) and quantum mechanics/molecular mechanics (QM/MM) calculations. This drug has been reported to act as both a noncovalent and covalent inhibitor and undergoes a stepwise inhibition by all its hydroxylated metabolites, which include 2-hydroxy-FYX-051, dihydroxy-FYX-051, and trihydroxy-FYX-051. However, the detailed mechanism of inhibition of each metabolite remains elusive and can be useful for designing more effective drugs with similar inhibition functions. Hence, herein we present the computational investigation of the structural and dynamical effects of FYX-051 and the calculated reaction mechanism for all of the oxidation steps catalyzed by the molybdopterin center in the active site. Calculated results for the proposed reaction mechanisms for each metabolite's inhibition reaction in the enzyme's active site, binding affinities, and the noncovalent interactions with the surrounding amino acid residues are consistent with previously reported experimental findings. Analysis of the noncovalent interactions via energy decomposition analysis (EDA) and noncovalent interaction (NCI) techniques suggests that residues L648, K771, E802, R839, L873, R880, R912, F914, F1009, L1014, and A1079 can be used as key interacting residues for further hybrid-type inhibitor development.

Dietary supplements and medicinal plants in urolithiasis: diet, prevention, and cure

BACKGROUND

Urolithiasis has been a major health concern for centuries, primarily owing to the limited treatment options in the physician's armamentarium. However, various studies have underscored a lesser incidence of urolithiasis in cohorts predominantly consuming fruits and vegetables. This article aims to review various dietary plants, medicinal herbs and phytochemicals in the prevention and management of urolithiasis.

METHODS

To provide context and evidence, relevant publications were identified on Google Scholar, PubMed and Science-Direct using keywords such as urolithiasis, nephrolithiasis, urolithiasis, renal stones, phytochemicals and dietary plants.

RESULTS

Growing bodies of evidence suggest the incorporation of plant-based foods, medicinal and herbal supplements, and crude drugs containing phytochemicals into the staple diet of people. The anti-urolithiatic activity of these plant bioactives can be attributed to their antioxidant, antispasmodic, diuretic, and inhibitory effect on the crystallization, nucleation and crystal aggregation effects. These mechanisms would help alleviate the events and symptoms that aid in the development and progression of renal calculi. In addition, it will also avoid the exacerbation of secondary disorders like inflammation and injury, which can initiate a vicious circle in turn worsening the disease progression.

CONCLUSION

In conclusion, the results presented in the review demonstrate the promising role of various dietary plants, medicinal and herbal supplements, and phytochemicals in preventing and managing the precipitation of uroliths. However, more conclusive and cogent evidence from preclinical and clinical studies is required to substantiate their safety, efficacy and toxicity profiles in humans.

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.

Females present higher dose-adjusted drug concentrations of metoprolol and allopurinol/oxypurinol than males

Females present a higher risk of adverse drug reactions. Sex-related differences in drug concentrations may contribute to these observations but they remain understudied given the underrepresentation of females in clinical trials. The aim of this study was to investigate whether anthropometric and socioeconomic factors and comorbidities could explain sex-related differences in concentrations and dosing for metoprolol and oxypurinol, the active metabolite of allopurinol. We conducted an analysis of two cross-sectional studies. Participants were self-described "White" adults taking metoprolol or allopurinol selected from the Montreal Heart Institute Hospital Cohort. A total of 1007 participants were included in the metoprolol subpopulation and 459 participants in the allopurinol subpopulation; 73% and 86% of the participants from the metoprolol and allopurinol subpopulations were males, respectively. Females presented higher age- and dose-adjusted concentrations of both metoprolol and oxypurinol (both p < 0.03). Accordingly, females presented higher unadjusted and age-adjusted concentration:dose ratio of both metoprolol and allopurinol/oxypurinol compared to males (all p < 3.0 × 10^-4 ). Sex remained an independent predictor of metoprolol concentrations (p < 0.01), but not of oxypurinol concentrations, after adjusting for other predictors. In addition to sex, age, daily dose, use of moderate to strong CYP2D6 inhibitors, weight, and CYP2D6 genotype-inferred phenotype were associated with concentrations of metoprolol (all p < 0.01). Daily dose, weight, estimated glomerular filtration rate (eGFR), and employment status were associated with oxypurinol concentrations (all p < 0.01). Females present higher dose-adjusted concentrations of metoprolol and oxypurinol than males. This suggests the need for sex-specific dosing requirements for these drugs, although this hypothesis should be validated in prospective studies.

Association between use of febuxostat and muscle injury: A disproportionality analysis and meta-analysis of randomized controlled trials

AIMS

Several reports have suggested an association between febuxostat and muscle injury. The purpose of this study was to determine whether febuxostat increases the risk of muscle injury. This study included an analysis of the US Food and Drug Administration Adverse Event Reporting System (FAERS) database and a systematic review/meta-analysis of randomized controlled trials.

METHODS

First, evaluation of the FAERS data included a disproportionality analysis that compared patients with and without rhabdomyolysis according to whether they were receiving febuxostat or allopurinol. Second, a systematic review/meta-analysis was performed to assess the risk of rhabdomyolysis and muscle injury in patients who used febuxostat or allopurinol.

RESULTS

Analysis of the FAERS data revealed disproportionality for increasing rhabdomyolysis in patients who received febuxostat (reporting odds ratio 4.49, 95% confidence interval [CI] 3.72-5.38, P < .01) and allopurinol (reporting odds ratio 2.49, 95% CI 2.25-2.75, P < .01). Nineteen studies were eligible for inclusion in the systematic review/meta-analysis. Rhabdomyolysis was reported in only 1 study. The risk of any type of muscle damage was not significantly increased with febuxostat compared with placebo (risk ratio 0.92, 95% CI 0.73-1.17, P = .52, I²  = 0%; 8 studies including 2597 participants, high-certainty evidence) or allopurinol (risk ratio 1.03, 95% CI 0.94-1.11, P = .56, I²  = 0%; 9 studies including 17 644 participants, moderate-certainty evidence).

CONCLUSION

Febuxostat does not seem to affect the risk of muscle injury. However, the findings of this meta-analysis indicate a need for further high-quality observational studies with long-term follow-up.

Ultrasonography in the prediction of gout flares: a 12-month prospective observational study

OBJECTIVES

To evaluate whether US findings indicating MSU deposits and US-detected inflammation (i.e. power Doppler signal) predict gout flares over 12 months.

METHODS

Gout patients on urate-lowering therapy for at least the preceding 6 months were enrolled consecutively in this 12-month prospective, observational, single-centre study. A nested case-control analysis was performed. Cases were participants with at least one flare in the follow-up period, while controls did not self-report any gout flare. The US assessment included elbows, wrists, second MCP joints, knees, ankles, and first MTP joints. The US findings indicating MSU deposits [i.e. aggregates, double contour (DC) sign and tophi] were identified as present/absent according to the Outcome Measure in Rheumatology definitions. Power Doppler signal was scored semiquantitatively. Summated scores were calculated for each US finding.

RESULTS

Eighty-one gout participants were enrolled, and 71 completed the study. Thirty (42.3%) of 71 participants experienced at least one flare over 12 months, with a median of 2.0 flares. Cases had a greater US burden of MSU deposits (6.7 ± 4.7 vs 2.9 ± 2.6, P = 0.01) and power Doppler signal (3.73 ± 3.53 vs 0.82 ± 1.44, P < 0.01) than controls, at baseline. The baseline US scores indicating MSU deposits and US-detected inflammation were significantly associated with the occurrence (total MSU score, adjusted odds ratio:1.75, 95% CI: 1.26, 2.43; power Doppler score, adjusted odds ratio: 1.63, 95% CI: 1.12, 2.40) and the number (total MSU score, adjusted incidence risk ratio: 1.17, 95% CI: 1.08, 1.26; power Doppler score, adjusted incidence risk ratio: 1.29, 95% CI: 1.19, 1.40) of flares over 12 months in multivariate analyses.

CONCLUSIONS

Baseline US findings indicating MSU deposits and US-detected inflammation are independent predictors of gout flares over 12 months.

`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.

Hypouricemic and nephroprotective effects of palmatine from Cortex Phellodendri Amurensis: A uric acid modulator targeting Keap1-Nrf2/NLRP3 axis

ETHNOPHARMACOLOGICAL RELEVANCE

Palmatine (Pal) is a major bioactive alkaloid originated from ancient Chinese herbal medicine Cortex Phellodendri Amurensis (CPA), which has long been applied to treat hyperuricemia (HUA)-related diseases. Pal possesses potent anti-inflammatory and anti-oxidant effects against metabolic diseases. However, its potential beneficial effect against PO (potassium oxonate)/HX (hypoxanthine)-induced HUA remains elusive.

AIM OF THE STUDY

This study aimed to investigate the potential pharmacological effect and mechanism of Pal on PO/HX-induced HUA in mice.

MATERIAL AND METHODS

A mouse model of HUA was established by co-administration of PO/HX once daily for 7 consecutive days. The HUA mice were orally given three doses (25, 50 and 100 mg/kg) of Pal daily for a week. Febuxostat (Feb, 5 mg/kg) was given as a positive control. At the scheduled termination of the experiment, the whole blood, liver and kidney were collected for subsequent analyses. The concentrations of uric acid (UA), creatinine (CRE) and blood urea nitrogen (BUN), and activities of adenosine deaminase (ADA) and xanthine oxidase (XOD) were evaluated. Histopathological alterations of the kidney were detected by H&E staining. The inflammatory and oxidative stress status was detected by assay kits. Additionally, key proteins involved in the urate transporter, Keap1-Nrf2 and TXNIP/NLRP3 signaling pathways were evaluated by immunohistochemistry and Western blotting. Finally, molecular docking was employed to probe the binding characteristics of Pal and target proteins Keap1, NLRP3, URAT1 and HO-1.

RESULTS

Administration of Pal substantially decreased the elevated kidney weight, lowered UA, CRE and BUN levels, and attenuated abnormal histopathological alterations. Meanwhile, treatment with Pal also dramatically lowered hepatic XOD and ADA activities. Besides, Pal treatment effectively mitigated the renal inflammatory and oxidative stress markers. Further mechanistic investigation indicated Pal distinctly downregulated the protein levels of GLUT9 and URAT1, while up-regulated the expression levels of OAT1 and ABCG2. Pal also restored Nrf2 activation, promoted subsequent expression of anti-oxidative enzymes, and downregulated the expressions of TXNIP, NLRP3, apoptosis-associated speck-like (ASC), caspase-1, IL-1β and IL-18. Molecular docking analysis also indicated Pal firmly bound with Keap1, NLRP3, URAT1 and HO-1.

CONCLUSIONS

These findings indicated that Pal exhibited favorable anti-HUA effect via modulating the expressions of transporter-related proteins and suppressing XOD activity. Furthermore, Pal also alleviated HUA-induced kidney injury, which was at least partially related to restoring Keap1-Nrf2 pathway and inhibiting TXNIP/NLRP3 inflammasome. Our investigation was envisaged to provide experimental support for the traditional application of CPA and CPA-containing classical herbal formulas in the management of HUA-related diseases and might provide novel dimension to the clinical application of Pal.

Identification and characterization of stress degradation products of febuxostat employing ultra-performance liquid chromatography-ultraviolet/photodiode array and liquid chromatography-mass spectrometry/time-of-flight studies

RATIONALE

Febuxostat (FEB) is a xanthine oxidase inhibitor approved by the U.S. Food and Drug Administration for long-term treatment of gout and hyperuricemia. There were no reports on identification and characterization of stress degradation products of the drug.

METHODS

FEB was subjected to forced decomposition conditions such as hydrolysis (neutral, acidic, and alkaline), oxidation, photolysis, and thermal stress, per the ICH guideline Q1A(R2). The degradation products formed were subjected to ultra-performance liquid chromatography (UPLC) on a C18 Kinetex column (100 × 4.6 mm, 2.6 μm) using isocratic elution method. Detection wavelength was 317 nm. The developed method was extended to UPLC-mass spectrometry/time of flight (MS/TOF) studies to identify and characterize the degradation products.

RESULTS

The drug exhibited significant degradation under alkaline/neutral hydrolytic, alkaline/acidic photolytic, and oxidative conditions, whereas it remained stable under acid hydrolytic, neutral photolytic, and thermal conditions. In total, eight degradation products (I-VIII) were formed, which could be adequately determined from the drug using the developed UPLC method. Of the eight degradation products identified from the liquid chromatography-ultraviolet (LC-UV) chromatogram, five (III and IV and VI-VIII) could be characterized using their MS/TOF spectral data. The degradation pathway leading to the formation of the products was postulated, and this is not reported so far.

CONCLUSIONS

Forced degradation studies were conducted on FEB, and the degradation products produced were identified by their mass spectral data obtained using LC-MS studies.

Umpolung Asymmetric 1,5-Conjugate Addition via Palladium Hydride Catalysis

Electronically matched nucleophilic 1,6-conjugate addition has been well studied and widely applied in synthetic areas. In contrast, nucleophilic 1,5-conjugate addition represents an electronically forbidden process and is considered unfeasible. Here, we describe modular protocols for 1,5-conjugate addition reactions via palladium hydride catalysis. Both palladium and synergistic Pd/organocatalyst systems are developed to catalyze 1,5-conjugate reaction, followed by inter- or intramolecular [3+2] cyclization. A migratory 1,5-addition protocol is established to corroborate the feasibility of this umpolung concept. The 1,5-addition products are conveniently transformed into a series of privileged enantioenriched motifs, including polysubstituted tetrahydrofuran, dihydrofuran, cyclopropane, cyclobutane, azetidine, oxetane, thietane, spirocycle and bridged rings. Preliminary mechanistic studies corroborate the involvement of palladium hydride catalysis.

Risk factors and management of hyperuricemia after renal transplantation

Hyperuricemia (HUA) is a common complication after renal transplantation. Currently, there is no uniform consensus on factors which increase the risk for and treatment of HUA in renal transplant recipients. The purpose of this review is to summarize current and proposed risk factors and strategies to manage HUA after renal transplantation in order to assist renal function protection and prolong graft survival time.

Low-dose febuxostat exhibits a superior renal-protective effect and non-inferior safety profile compared to allopurinol in chronic kidney disease patients complicated with hyperuricemia: A double-centre, randomized, controlled study

WHAT IS KNOWN AND OBJECTIVE

The present study compared the efficacy and safety of low-dose febuxostat versus allopurinol in chronic kidney disease (CKD) patients complicated with hyperuricemia (HUA).

METHODS

In this double-centre, randomized, controlled study, 120 CKD patients complicated with HUA were recruited and randomly assigned to low-dose febuxostat group (20 mg/day) or allopurinol group (200 mg/day) at 1:1 ratio. The serum creatinine (Scr), serum uric acid (SUA), and estimated glomerular filtration rate (eGFR) were measured at baseline (M0), month (M) 1, M3, and M6. Besides, the drug-related adverse events (AEs) were recorded. The primary outcome was the proportion of patients showing a > 10% decline in eGFR from M0 to M6.

RESULTS

The eGFR level was increased at M6, but similar at M0, M1 and M3 in febuxostat group compared with allopurinol group. Notably, the proportion of patients with >10% decline in eGFR from M0 to M6 was decreased in febuxostat group compared with allopurinol group. However, there was no difference of Scr, SUA at M0, M1, M3 and M6 between febuxostat group and allopurinol group. Moreover, there was no difference of drug-related AEs between febuxostat group and allopurinol group. Further subgroup analysis exhibited that low-dose febuxostat presented superior effect on attenuating eGFR decline and lowering SUA level compared with allopurinol in CKD stage 3 subgroup, but not in CKD stage 2 subgroup.

CONCLUSION

Low-dose febuxostat may exhibit a superior renal-protective effect, non-inferior SUA lowering ability and safety profile compared with allopurinol in CKD patients complicated with HUA.