Switching from allopurinol to febuxostat for the treatment of hyperuricemia and renal function in patients with chronic kidney disease

Multicenter randomized controlled trial of intensive uric acid lowering therapy for CKD patients with hyperuricemia: TARGET-UA

BACKGROUND

We investigate whether Intensive uric acid (UA)-lowering therapy (ULT) provides increased renal protection compared with standard therapy in chronic kidney disease (CKD) patients.

METHODS

This was a multicenter randomized controlled trial. Only CKD patients with hyperuricemia were included in this study. The participants were randomly assigned to either the Intensive therapy group (target serum UA level ≥ 4.0 mg/dL and < 5.0 mg/dL) or the standard therapy group (serum UA level ≥ 6.0 mg/dL and < 7.0 mg/dL). ULT was performed using topiroxostat, a non-purine-type selective xanthine oxidase inhibitor. The primary endpoint was change in the logarithmic value of urine albumin to the creatinine ratio (ACR) between baseline and week 52 of the treatment.

RESULTS

Three hundred fifty-two patients were included in the full analysis set. In the Standard therapy group, mean serum UA was 8.23 mg/dL at baseline and 6.13 mg/dL at 52 weeks. In the Intensive therapy group, mean serum UA was 8.15 mg/dL at baseline and 5.25 mg/dL at 52 weeks. There was no significant difference in changes in log ACR at 52 weeks between the Intensive therapy and the Standard therapy groups.

CONCLUSION

This study did not reveal the benefit of Intensive ULT to improve albuminuria levels. (UMIN000026741 and jRCTs051180146).

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

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

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.

Longitudinal changes in uric acid concentration and their relationship with chronic kidney disease progression in children and adolescents

BACKGROUND

Elevated serum uric acid concentration is a risk factor for CKD progression. Its change over time and association with CKD etiology and concomitant changes in estimated glomerular filtration rate (eGFR) in children and adolescents are unknown.

METHODS

Longitudinal study of 153 children/adolescents with glomerular (G) and 540 with non-glomerular (NG) etiology from the CKD in Children (CKiD) study. Baseline serum uric acid, change in uric acid and eGFR over time, CKD etiology, and comorbidities were monitored. Adjusted linear mixed-effects regression models quantified the relationship between within-person changes in uric acid and concurrent within-person changes in eGFR.

RESULTS

Participants with stable uric acid over follow-up had CKD progression which became worse for increased baseline uric acid (average annual percentage changes in eGFR were - 1.4%, - 7.7%, and - 14.7% in those with G CKD with baseline uric acid < 5.5 mg/dL, 5.5 - 7.5 mg/dL, and > 7.5 mg/dL, respectively; these changes were - 1.4%, - 4.1%, and - 8.6% in NG CKD). Each 1 mg/dL increase in uric acid over follow-up was independently associated with significant concomitant eGFR decreases of - 5.7% (95%CI - 8.4 to - 3.0%) (G) and - 5.1% (95%CI - 6.3 to - 4.0%) (NG) for those with baseline uric acid < 5.5 mg/dL and - 4.3% (95%CI - 6.8 to - 1.6%) (G) and - 3.3% (95%CI - 4.1 to - 2.6%) (NG) with baseline uric acid between 5.5 and 7.5 mg/dL.

CONCLUSIONS

Higher uric acid levels and increases in uric acid over time are risk factors for more severe progression of CKD in children and adolescents. A higher resolution version of the Graphical abstract is available as Supplementary information.

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.

Palpable tophi and more comorbidities associated with adherence to urate-lowering medical therapy in a Chinese gout cohort

OBJECTIVE

Urate-lowering therapy (ULT) nonadherence is common and problematic in gout. Since, sociocultural factors affect adherence, we analyzed a Chinese cohort.

METHODS

We studied 903 Chinese gout patients aged 46.4±14.7 years (mean±SD), uniquely extending to assay of 2-year medication possession ratio (MPR) ≥80% defined as high adherence. Multivariable logistic regression analyses evaluated factors linked with adherence and ULT target attainment.

RESULTS

Characterization of ULT outcomes in this cohort revealed that after 2 years ULT, MPR ≥80% patients had better target serum urate (SU) achievement (from 23.3% to 71.0%, P <0.001), lower flare frequency and palpable tophi compared to MPR <80%. However, only 44.7% of cohort subjects had MPR ≥80%. Male sex (OR 3.68), gout onset age >60 years (OR 3.51), disease duration >5 years (OR 1.70), more comorbidities (OR 1.74), baseline palpable tophi (OR 1.53), SU <6mg/dL (360μmol/L) (OR 1.92) and more frequent follow-up visits (OR 1.98) were significantly associated with high adherence. Nevertheless, significant independent risk factors for failed SU target achievement included male sex (OR 0.36) and more comorbidities (OR 0.85).

CONCLUSION

Despite adherence to ULT linked to better outcomes for flares and tophi, the more adherent Chinese male patients and those with more comorbidities had decreased target SU attainment. Differences in adherence of Chinese gout patients compared to several primarily Western studies emphasize the importance of not stereotyping gout patients for projected nonadherence. Results underline the dual importance of identifying gout patients more likely to be ULT-adherent and leveraging adherence to drive treatment to SU target.

Febuxostat Improves Uric Acid Levels and Renal Function in Patients with Chronic Kidney Disease and Hyperuricemia: A Meta-Analysis

Background. Uric acid nephropathy, also known as hyperuricemia nephropathy or gouty nephropathy, is characterized by uric acid crystal deposition and inflammatory cell infiltration. Herein, we aimed to demonstrate the role of febuxostat on uric acid levels and renal function in patients with chronic kidney disease and hyperuricemia. Methods. Eight databases included were searched for clinical randomized controlled trials. Meanwhile, the confidence interval (CI) of either relative risk or mean difference was set to 95%. Besides, the heterogeneity of the research results is tested by $I^2$ . Results. Ten studies were ultimately included in this meta-analysis. All of them were considered to be random controlled trials. 10 studies reported the serum uric acid of the test group and the control group, which was significantly lower (SMD: -146.44, 95% Cl: -195.96, -86.93, and $P<0.01$ ) than the control group, EGFR (SMD: 3.21, 95% Cl: 1.17, 5.25, and $P<0.01$ ), serum creatinine (SMD: -15.27, 95% Cl: -20.75, -9.79, and $P<0.01$ ), serum urea nitrogen (SMD: -2.37, 95% Cl: -3.31, -1.61, and $P<0.01$ ), and adverse reactions (OR: 0.74, 95% Cl: 0.32, 1.68, and $P=0.47$ ). Conclusion. The results of this study suggest that febuxostat may be effective in patients with CKD with HUA, as evidenced by serum uric acid, creatinine, urea nitrogen, and EGFR. However, large sample, multicenter, low risk of bias clinical studies, as well as basic medical research, are needed.

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

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

Hyperuricemia, the heart, and the kidneys - to treat or not to treat?

Background

Hyperuricemia is a state in which the serum levels of uric acid are elevated. As such it has a pronounced effect on vascular and renal function with their consequences, while also showing some antioxidant effects that show to be beneficial.

Summary

Hyperuricemia has shown to have a J-shaped relationship with mortality, is frequently associated with development and progression of heart and kidney disease, and is correlated with malnutrition-inflammation-atherosclerosis syndrome, although several Mendelian studies have failed to show an association with morbidity and mortality. Hyperuricemia is usually associated with gout flares and tophi development but can also present as asymptomatic hyperuricemia. It is still uncertain whether asymptomatic hyperuricemia is an independent risk factor for cardiovascular or renal disease and as such its treatment is questionable.

Key messages

Some possible tools for future decision making are the use of noninvasive techniques such as pulse wave analysis, urinary sediment analysis, and joint ultrasound, which could help identify individuals with asymptomatic hyperuricemia that could benefit from urate lowering therapy most.

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

Background

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

Methods

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

Results

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

Conclusion

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

Trial registration

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

Renal safety and urate-lowering efficacy of febuxostat in gout patients with stage 4-5 chronic kidney disease not yet on dialysis

BACKGROUND/AIMS

The safety and efficacy of febuxostat in patients with stage 4-5 chronic kidney disease (CKD) are still unclear owing to a lack of studies in these patients. Therefore, we aimed to evaluate the effect of febuxostat on renal function, general safety, and efficacy in gout patients with stage 4-5 CKD.

METHODS

Among 739 patients who had been administered febuxostat from May 2012 to December 2016 at a single hospital in Korea, 370 patients who had been monitored for 1 year were analyzed. Serum uric acid levels and estimated glomerular filtration rate (eGFR) of patients with gouty arthritis were collected at baseline and 1 year after febuxostat administration.

RESULTS

Among the 370 patients, 280 patients were stage 1-3 CKD, 63 patients were stage 4-5 CKD, and 27 patients were on dialysis. The eGFR of 63 patients with stage 4-5 CKD, excluding dialysis patients, was 19.84 ± 7.08 mL/min/1.73 m2 when they began to take febuxostat and 23.49 ± 16.67 mL/min/1.73 m2 after 12 months (p = 0.13). The urate-lowering effect after 12 months of febuxostat medication showed statistical significance (8.96 ± 2.31 mg/dL at baseline and 4.88 ± 1.68 mg/dL after 12 months, p < 0.01). The difference in incidence of adverse events among patients with stage 1-3 CKD, those with stage 4-5 CKD, and those on dialysis was not significant.

CONCLUSION

Febuxostat demonstrated renal safety and good urate-lowering efficacy in gout patients with stage 4-5 CKD, who are not yet on dialysis.

Intensive uric acid-lowering therapy in CKD patients: the protocol for a randomized controlled trial

BACKGROUND

Hyperuricemia would be a risk factor for the development/progression of CKD. However, several studies showed U-shape association between serum uric acid level and renal impairment, suggesting that hypouricemia was rather associated with renal dysfunction. Perhaps, there is the optimal target level of serum UA for renal function.

METHODS

The Target-UA study is a multicenter randomized controlled trial. Eligible CKD patients (eGFR ≥ 30, < 60 mL/min/1.73 m2 and urine protein < 0.5 g/gCr or urine albumin to creatinine ratio (ACR) < 300 mg/gCr) with serum UA ≥ 8.0 mg/dL (≥ 7.0 mg/dl: under the treatment) will be enrolled and be randomly assigned to the intensive therapy group (target serum UA level ≥ 4.0 mg/dL, < 5.0 mg/dL) or the standard therapy group (serum UA level ≥ 6.0 mg/dL, < 7.0 mg/dL). Topiroxostat, a new xanthine oxidase inhibitor, will be administered to treat hyperuricemia. The primary endpoint is a change in logarithmic value of urine ACR between baseline and week 52 of treatment. The secondary endpoints include changes in serum UA, eGFR, urine protein, lipid profile, and onset of composite cardiovascular events, renal events, gouty arthritis, and attack of urolithiasis. The number of subjects has been set to be 185 in each group for a total of 370.

DISCUSSION

This is the first study, to the best of our knowledge, to determine the optimal target level of serum UA for renal protection and is expected to lead to progress in CKD treatment.

TRIAL REGISTRATION

(UMIN000026741 and jRCTs051180146).

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

AIM

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

PARTICIPANTS

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

EVIDENCE

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

CONSENSUS PROCESS

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

CONCLUSION

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

Development of an optimized febuxostat self-nanoemulsified loaded transdermal film: in-vitro, ex-vivo and in-vivo evaluation

Febuxostat (FBX) is used to treat gout and chronic hyperuricemia. However, its bioavailability is moderate (49%) as a result of low solubility and first-pass metabolism. Therefore, the aim of our study is to improve FBX bioavailability by enhancement its solubility using self-nanoemulsifying drug delivery system (SNEDDS) technique in the form of transdermal film to avoid hepatic metabolism. To accomplish this goal, Eight SNEDDS formulae were prepared according to a three-factor, two-level D-Optimal mixture design to evaluate the effect of different ratios of the Lemon oil (X1), the surfactant Tween-20 (X2), and the co-surfactant PEG-400 (X3) on the globule size in order to reach smallest globular size. Results revealed that SNEDDS globule size ranged from 177 to 454 nm. The optimized formula consisted of 20% oil, 40% surfactant and 40% co-surfactant. Diffusion study showed improved enhancement in skin permeation that was confirmed by imaging using fluorescence microscope. In vivo plasma data showed significant (p < 0.05) difference in FBX plasma levels and pharmacokinetic parameters when compared with raw FBX loaded film. In conclusion, FBX-SNEDDS loaded transdermal film could be a successful way to improve solubility and skin permeability that would lead to improvement in patient's compliance.

Comparative Renoprotective Effect of Febuxostat and Allopurinol in Predialysis Stage 5 Chronic Kidney Disease Patients: A Nationwide Database Analysis

Hyperuricemia has been associated with chronic kidney disease (CKD) progression. The antihyperuricemic febuxostat's potential renoprotective effect has been demonstrated in stage 1–3 CKD. Large‐scale studies comparing the renoprotective potential of febuxostat and allopurinol in advanced CKD are lacking. We exclusively selected 6,057 eligible patients with predialysis stage 5 CKD prescribed either febuxostat or allopurinol using the National Health Insurance Research Database in Taiwan during 2012–2015. There were 69.57% of allopurinol users and 42.01% febuxostat users who required long‐term dialysis (P < 0.0001). The adjusted hazard ratio (HR) of 0.65 (95% confidence interval (CI) 0.60–0.70) indicated near 35% lower hazards of long‐term dialysis with febuxostat use. The renal benefit of febuxostat was consistent across most patient subgroups and/or using the propensity score‐matched cohort. The adjusted HR was 0.66 (95% CI, 0.61–0.70) for long‐term dialysis or death. In conclusion, lower risk of progression to dialysis was observed in predialysis stage 5 CKD febuxostat users without compromising survival.

Phloretin ameliorates hyperuricemia-induced chronic renal dysfunction through inhibiting NLRP3 inflammasome and uric acid reabsorption

BACKGROUND

Hyperuricemia (HUA) is an important risk factor for renal diseases and contributes to renal fibrosis. It has been proved that phloretin has antioxidant and anti-inflammatory properties and could inhibit uric acid (UA) uptake in vitro. However, whether phloretin has a renal protective role in vivo remains unknown.

PURPOSE

This study aims to evaluate the therapeutic effect of phloretin on HUA-induced renal injury in mice and to reveal its underlying mechanism.

METHODS

Mice were induced hyperuricemic by oral gavage of adenine/potassium oxonate. The effects of phloretin on renal function, fibrosis, oxidative stress, inflammation, and UA metabolism in HUA mice were evaluated. The effect of phloretin on NLRP3 pathway was analyzed in human renal tubular cell lines (HK-2).

RESULTS

HUA mice showed renal dysfunction with increased renal fibrosis, inflammation and mitochondrial stress. By contrast, phloretin reduced the level of serum blood urea nitrogen (BUN), urinary albumin to creatinine ratio (UACR), tubular necrosis, extracellular matrix (ECM) deposition and interstitial fibroblasts in HUA mice. The renal infiltration of inflammatory cells, cytokines such as NOD-like receptor family pyrin domain containing 3 (NLRP3) and interleukin-1β (IL-1β) release, mitochondrial reactive oxygen species (ROS) and morphological lesions in HUA mice also decreased. Furthermore, phloretin partly inhibited renal glucose transporter 9 (GLUT9) and promoted urinary UA excretion in HUA mice. In vitro, phloretin suppressed the NLPR3 pathway under LPS or UA stimulation in HK-2 cells.

CONCLUSIONS

Phloretin could effectively attenuate UA-induced renal injury via co-inhibiting NLRP3 and UA reabsorption, and thus it might be a potential therapy to hyperuricemia-related renal diseases.

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

Background

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

Methods

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

Results

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

Conclusions

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

Electronic supplementary material

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

Switching from allopurinol to febuxostat: efficacy and safety in the treatment of hyperuricemia in renal transplant recipients

The aim of this study was to evaluate the efficacy and tolerability of febuxostat in renal transplant recipients who were previously treated with allopurinol (the daily oral dose is 100 mg). A 6-month cohort study was conducted with 46 renal transplant recipients who had hyperuricemia. In 22 patients, treatment was changed from allopurinol to febuxostat (febuxostat was given at an oral dose of 20 mg once a day), and the other 24 patients continued the allopurinol treatment (the daily oral dose is 100 mg). The serum levels of uric acid (UA), creatinine, other biochemical parameters, estimated glomerular filtration rate (eGFR), and adverse events were measured at baseline as well as at 1, 3, and 6 months after the switch to febuxostat. Serum UA levels significantly decreased from 470.82 ± 34.37 to 378.77 ± 51.97 μmol/L in the febuxostat group, and decreased from 469.46 ± 33.47 to 428.21 ± 23.37 μmol/L in the allopurinol group. The eGFR increased from 75.55 to 85.23 mL/min in the febuxostat group, and decreased from 78.79 to 70.31 mL/min in the allopurinol group. In renal transplant recipients, febuxostat reduced the serum UA levels resulting in minor short-term improvement of renal function with no changes in the other biochemical parameters.

Pharmacological urate-lowering approaches in chronic kidney disease

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

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

What is known and objective

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

Methods

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

Results and discussion

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

What is new and conclusion

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

Impact of pegloticase on patient outcomes in refractory gout: current perspectives

Gout is currently the most frequent cause of inflammatory arthritis worldwide and is responsible for poor health-related quality of life and loss of work productivity. It is caused by high levels of serum urate, leading to the deposition of monosodium urate crystals in joints and soft tissues. This condition is associated with acute flares and, if untreated or refractory, chronic and potentially destructive arthritis and tophi formation. Pegloticase is a recombinant, pegylated uricase used in the treatment of gout patients who fail conventional urate-lowering therapy. In this review, we discuss the impact of pegloticase on patient outcomes in refractory gout. We analyze different parameters, such as plasma uric acid concentration, frequency of flares, tophi reduction, pain, function, quality of life, and safety.

Efficacy and safety of febuxostat for treating hyperuricemia in patients with chronic kidney disease and in renal transplant recipients: A systematic review and meta-analysis

Febuxostat is potent and well-tolerated in the management of chronic gout. However, its clinical efficacy and safety in the treatment of hyperuricemia in patients with chronic kidney disease (CKD) and in renal transplant recipients have remained to be fully determined. The MEDLINE, EMBASE and Cochrane Library databases were searched for relevant articles. Data were extracted and pooled results were estimated from the standard mean difference (SMD) with 95% confidence intervals (95% CIs). The quality of the studies included was assessed, and their publication bias was examined. Four prospective randomized controlled trials and two retrospective observational studies were included in the systematic review and meta-analysis. Febuxostat administration significantly reduced the serum uric acid concentration in patients with CKD and in renal transplant recipients when compared with allopurinol or placebo in the short-term (1 month: SMD, −2.24; 95% CI, −3.59 to −0.89; P-value of SMD=0.001; I², 92.4%; 3 months: SMD, −1.20; 95% CI, −2.04 to −0.36; P-value of SMD=0.005; I², 88.9%; 6 months: SMD, −1.49; 95% CI, −2.68 to −0.30; P-value of SMD=0.014; I², 92.9%). Furthermore, the increase in the estimated glomerular filtration rate in the febuxostat group was significantly higher than that in the control group (SMD, 0.30; 95% CI, 0.031 to 0.58; P-value of SMD=0.029; I², 0.0%). No significant difference in the changes in serum creatinine (Scr), low-density lipoprotein (LDL) and high-density lipoprotein (HDL) was identified between the two groups (Scr: SMD, −0.17; 95% CI, −0.97 to 0.63; P-value of SMD=0.67; I², 79.2%; LDL: SMD, −0.21; 95% CI, −0.49 to 0.07; P-value of SMD=0.13; I², 34.1%; HDL: SMD, −0.05; 95% CI, −0.70 to 0.61; P-value of SMD=0.89; I², 69.2%). In conclusion, febuxostat is a potent and well-tolerated agent for the short-term management of hyperuricemia in patients with CKD and in renal transplant recipients. However, these data should be interpreted with caution due to the varied design of the studies included in the present meta-analysis.

The impact of serum uric acid reduction on renal function and blood pressure in chronic kidney disease patients with hyperuricemia

BACKGROUND

Febuxostat is tolerable in chronic kidney disease (CKD) patients with hyperuricemia. However, the long-term effect of lowering uric acid with febuxostat on renal function and blood pressure has not been elucidated.

METHODS

This was a 2 years retrospective observational study. 86 CKD patients with hyperuricemia who continued with allopurinol (allopurinol group, n = 30), switched from allopurinol to febuxostat (switched group, n = 25), or were newly prescribed febuxostat (febuxostat group, n = 31) were included in this study. Serum uric acid, estimated glomerular filtration rate (eGFR), blood pressure, and urinary protein were analyzed. Moreover, the impact of serum uric acid reduction on renal function and blood pressure was assessed.

RESULTS

Serum uric acid in the switched and febuxostat groups was significantly reduced at 6 months (switched group; 8.49 ± 1.32-7.19 ± 1.14 mg/dL, p < 0.0001, febuxostat group; 9.43 ± 1.63-6.31 ± 0.90 mg/dL, p < 0.0001). In the allopurinol group, serum uric acid was increased (6.86 ± 0.87-7.10 ± 0.85 mg/dL, p = 0.0213). eGFR was significantly increased (35.2 ± 12.8-37.3 ± 13.9 mL/min/1.73 m², p = 0.0232), while mean arterial pressure (93.1 ± 10.8-88.2 ± 9.5 mmHg, p = 0.0039) was significantly decreased at 6 months in the febuxostat group, resulting in the retention of eGFR for 2 years.

CONCLUSIONS

The impact of serum uric acid reduction might have beneficial effects on CKD progression and blood pressure. However, a large prospective study is needed to determine the long-term efficacy of febuxostat therapy in CKD patients with hyperuricemia.

Pharmacologic targeting ERK1/2 attenuates the development and progression of hyperuricemic nephropathy in rats

The pathogenesis of hyperuricemia-induced chronic kidney disease is largely unknown. In this study, we investigated whether extracellular signal–regulated kinases1/2 (ERK1/2) would contribute to the development of hyperuricemic nephropathy (HN). In a rat model of HN induced by feeding mixture of adenine and potassium oxonate, increased ERK1/2 phosphorylation and severe glomerular sclerosis and renal interstitial fibrosis were evident, in parallel with diminished levels of renal function and increased urine microalbumin excretion. Administration of U0126, which is a selective inhibitor of the ERK1/2 pathway, improved renal function, decreased urine microalbumin and inhibited activation of renal interstitial fibroblasts as well as accumulation of extracellular proteins. U0126 also inhibited hyperuricemia-induced expression of multiple profibrogenic cytokines/chemokines and infiltration of macrophages in the kidney. Furthermore, U0126 treatment suppressed xanthine oxidase, which mediates uric acid production. It also reduced expression of the urate anion exchanger 1, which promotes reabsorption of uric acid, and preserved expression of organic anion transporters 1 and 3, which accelerate uric acid excretion in the kidney of hyperuricemic rats. Finally, U0126 inhibited phosphorylation of Smad3, a key mediator in transforming growth factor (TGF-β) signaling. In cultured renal interstitial fibroblasts, inhibition of ERK1/2 activation by siRNA suppressed uric acid-induced activation of renal interstitial fibroblasts. Collectively, pharmacologic targeting of ERK1/2 can alleviate HN by suppressing TGF-β signaling, reducing inflammation responses, and inhibiting the molecular processes associated with elevation of blood uric acid levels in the body. Thus, ERK1/2 inhibition may be a potential approach for the prevention and treatment of hyperuricemic nephropathy.

Previous Dosage of Allopurinol Is a Strong Determinant of Febuxostat Efficacy

Febuxostat has currently played pivotal role in the treatment of hyperuricemia, but there is little comprehensive information for the determinants of individual difference in efficacy of febuxostat. Therefore, the present study, a retrospective investigation, was carried out to analyze the effects of patient characteristics on the efficacy of febuxostat. A total of 225 patients who were continuously prescribed the same dose of febuxostat for 8-12 weeks from the initial therapy were enrolled in the present study. The data, including patient information and laboratory data, were collected from electronic medical records. Serum urate lowering effects of febuxostat were evaluated by calculating the change in serum urate level at baseline and at 8-12 weeks after starting febuxostat. The multiple regression analysis showed the change in serum urate level was significantly lower in male patients and in those with a lower baseline serum urate level, higher previous dose of allopurinol, lower dose of febuxostat and lower body surface area-unadjusted estimated glomerular filtration rate. Concomitantly administered drugs did not show a significantly influence on the efficacy of febuxostat. In conclusion, it should be noted that the serum urate lowering efficacy of febuxostat may decrease in patients with a higher previous dose of allopurinol, renal impairment or male patients. The basic findings of the present study are believed to contribute to the proper use of febuxostat.

Efficacy and Safety of Febuxostat in Kidney Transplant Patients

OBJECTIVES

Febuxostat, a nonpurine xanthine oxidase, is known to be effective and safe, even in patients with chronic kidney disease. However, there are insufficient data about the efficacy and safety of febuxostat in kidney transplant patients.

MATERIALS AND METHODS

We reviewed medical records of all kidney transplant patients who were prescribed febuxostat between August 2012 and May 2015 at Asan Medical Center in Seoul, Korea. The efficacy and safety results of febuxostat in transplant patients were evaluated. To compare the efficacy of febuxostat, results of kidney transplant patients who were prescribed benzbromarone or allopurinol for more than 1 year during the same period were also reviewed.

RESULTS

Thirty-one patients were included in this study. The initial serum uric acid level of 481.83 ± 143.36 μmol/L decreased to 302.18 ± 150.50 μmol/L after 1 month of febuxostat use. Only 1 patient had altered sense of taste after taking febuxostat, but this symptom quickly improved and he continued treatment. No other adverse events were reported. In addition, at 12 months, mean serum uric acid levels were 280.77 ± 78.52 μmol/L in the febuxostat, 332.52 ± 72.57 μmol/L in the benzbromarone, and 363.45 ± 60.08 μmol/L in the allopurinol group. However, we found no apparent effect on estimated glomerular filtration rate (P = .344). The mean doses of febuxostat, benzbromarone, and allopurinol were 52.31 ± 5.33 mg/day, 42.19 ± 1.69 mg/day, and 146.67 ± 16.52 mg/day.

CONCLUSIONS

Febuxostat reduced serum uric acid levels effectively in kidney transplant patients without severe adverse events.

Impact of Uric Acid Levels on Kidney Disease Progression

BACKGROUND

Hyperuricemia is associated with the progression of chronic kidney disease (CKD), but it is not known whether the relationship is causal. We examined the association of hyperuricemia and uric acid lowering therapy (UALT) with progression of CKD in patients with CKD 3 and 4 in the Cleveland Clinic CKD registry.

METHODS

We included 1,676 patients with CKD stages 3 and 4 from Ohio, who had measured their uric acid (UA) levels a year prior to the recording of the second eGFR <60 mL/min/1.73 m2, and follow-up eGFR, between 2005 and 2009. Our primary composite outcome included a 50% drop in eGFR or progression to ESRD. Secondary outcomes included the rate of decline in eGFR, all-cause mortality, progression to ESRD, and a composite measure of progression to ESRD or death. We assessed the association between UA, UALT, and outcomes using Cox models and competing risks regression models.

RESULTS

In multivariable models, higher UA was associated with the composite endpoint, but it reached statistical significance only in the 4th quartile (≥8.9 mg/dL). Receipt of UALT was significantly associated with increased risk of the composite outcome. Neither UA nor UALT (considered a time-dependent covariate) was significantly associated with mortality. The inference was similar for UA as high vs. low, quartiles, or continuous. Similarly, neither high UA nor UALT were significantly associated with ESRD, the composite of ESRD and mortality, or eGFR decline.

CONCLUSIONS

Hyperuricemia is associated with increased risk of progression to ESRD in patients with CKD stages 3 and 4, but UALT does not ameliorate the risk, suggesting that the relationship is not causal.

Predictors of reaching a serum uric acid goal in patients with gout and treated with febuxostat

Purpose

Clinical guidelines recommend febuxostat as first-line pharmacologic urate-lowering therapy for patients with gout to achieve a goal serum uric acid (sUA) <6 mg/dL; however, little is known about other contributing factors. This study identified clinical characteristics of patients treated with febuxostat to develop and validate a predictive model for achieving a goal sUA.

Patients and methods

Patients with Humana Medicare or commercial insurance, diagnosed with gout and newly initiated on febuxostat (index date February 1, 2009 – December 31, 2013), were identified for a retrospective cohort study. Patients were followed for 365 days and the first valid sUA test result ≥120 days after index was retained. A stepwise logistic regression with backward elimination was estimated to model sUA goal attainment, and a linear model was estimated to model the impact of predictor variables on sUA level.

Results

The study sample (n=678) was divided into a development (training) dataset (n=453) and a validation (holdout) dataset (n=225). In the training sample, patients in the sUA <6 mg/dL group were on febuxostat for a longer time, were more adherent, and had a lower average base-line sUA level (all p<0.0001) vs patients in the sUA ≥6 mg/dL group. In the logistic model, febuxostat adherence (odds ratio [OR]=1.03, p<0.0001) and baseline sUA level (OR=0.84, p<0.0001) increased the odds of attaining sUA <6 mg/dL. In the linear regression model, increase in febuxostat adherence (p<0.0001), baseline sUA level (p<0.0001), advanced age (p=0.0021), and not having congestive heart failure (p<0.05) were associated with a reduction of sUA level. Pre-index allopurinol use was a marginally significant predictor of sUA level reduction (p=0.06).

Conclusions

Among febuxostat users diagnosed with gout in a real-world setting, adherence to febuxostat and lower baseline sUA level were the strongest predictors of attaining sUA goal. These findings may help clinicians to identify appropriate patients most likely to benefit from febuxostat treatment, and underscore the importance of medication adherence in this challenging patient population.

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

Background

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

Methods

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

Results

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

Conclusion

Febuxostat might be more renoprotective than allopurinol.

Comparative effectiveness of allopurinol versus febuxostat for preventing incident renal disease in older adults: an analysis of Medicare claims data

OBJECTIVE

To assess the comparative effectiveness of allopurinol versus febuxostat for preventing incident renal disease in elderly.

METHODS

In a retrospective cohort study using 2006-2012 Medicare claims data, we included patients newly treated with allopurinol or febuxostat (baseline period of 183 days without either medication). We used 5:1 propensity-matched Cox regression analyses to compare the HR of incident renal disease with allopurinol use (and dose) versus febuxostat (reference). Sensitivity analyses included multivariable-adjusted regression models.

RESULTS

There were 31 465 new allopurinol or febuxostat treatment episodes in 26 443 patients; 8570 ended in incident renal disease. Crude rates of incident renal disease per 1000 person-years were 192 with allopurinol versus 338 with febuxostat. Crude rates of incident renal disease per 1000 person-years were lower with higher daily dose: allopurinol <200, 200-299 and ≥300 mg/day with 238, 176 and 155; and febuxostat 40 and 80 mg/day with 341 and 326, respectively. In propensity-matched analyses, compared with febuxostat, allopurinol use was associated with lower HR of incident renal disease, 0.61 (95% CI 0.49 to 0.77). Compared with febuxostat 40 mg/day, allopurinol doses <200, 200-299 and ≥300 mg/day were associated with lower HR of incident renal disease, 0.75 (95% CI 0.65 to 0.86), 0.61 (95% CI 0.52 to 0.73) and 0.48 (95% CI 0.41 to 0.55), respectively. Sensitivity analyses using multivariable-adjusted regression confirmed these findings.

CONCLUSIONS

Allopurinol was associated with a lower risk of incident renal disease in elderly patients than febuxostat. Future studies need to examine the mechanism of this potential renal benefit of allopurinol.

Risk of Febuxostat-Associated Myopathy in Patients with CKD

BACKGROUND AND OBJECTIVES

Febuxostat, a nonpurine xanthine oxidase inhibitor, is widely used to treat hyperuricemia. Although febuxostat-associated rhabdomyolysis was reported in some patients with CKD, the association between CKD and febuxostat-associated myopathy remains uncertain.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Our retrospective cohort study included 1332 patients using febuxostat in Taipei Medical University-Wanfang Hospital from February of 2014 to January of 2016. The primary predictor was time-averaged eGFR as calculated by the equation proposed by the 2009 Chronic Kidney Disease Epidemiology Collaboration. The outcome was febuxostat-associated myopathy defined as elevated creatine kinase levels during febuxostat use that were not attributed to other muscular injuries.

RESULTS

The median duration of febuxostat use was 224 days (25th, 75th percentiles: 86, 441.5 days). Of 1332 study participants, 1222 (91.7%) had CKD; the median eGFR was 20.8 ml/min per 1.73 m2 (25th, 75th percentiles: 9.0, 35.4 ml/min per 1.73 m2). Forty-one of the participants had febuxostat-associated myopathy (3.2%). All patients with myopathy had CKD, and the incident rate was 0.013 (95% confidence interval, 0.01 to 0.02) events per 100 patient-days in patients with CKD. Of 41 patients with myopathy, 37 had myositis, and four had rhabdomyolysis. Myopathy resolved in 17 patients who withdrew from treatment and eight patients who continued febuxostat treatment. Among the evaluated predictors, multivariate analysis showed that only the lowest eGFR tertile was significantly associated with myopathy in febuxostat users. The odds ratio of the lowest eGFR tertile to the highest tertile was 4.21 (95% confidence interval, 1.7 to 10.43). This finding remained consistent among subgroups stratified by age, sex, diabetes status, coronary artery disease, and statin or fibrate use.

CONCLUSIONS

Patients with severely reduced eGFR had higher risk of myopathy with treatment of febuxostat. Regular monitoring of creatine kinase level is suggested for early detection of febuxostat-associated myopathy, particularly in patients with CKD.

Any link of gout disease control among hypertensive patients and onset of end-stage renal disease? Results from a population-based study

AIM

To determine the impact of allopurinol non-adherence as a proxy for uncontrolled disease on primary prevention of end-stage renal disease (ESRD).

METHODS

A cohort of 2752 patients with gout diagnosis was reconstructed using the Québec Régie de l’assurance maladie du Québec and MedEcho administrative databases. Eligible patients were new users of allopurinol, aged 45-85, with a diagnosis of hypertension, and treated with an antihypertensive drug between 1997 and 2007.

RESULTS

Major risk factor for ESRD onset was chronic kidney disease at stages 1 to 3 [rate ratio (RR) = 8.00; 95% confidence interval (CI): 3.16-22.3 and the severity of hypertension (≥ 3 vs < 3 antihypertensives)] was a trending risk factor as a crude estimate (RR = 1.94; 95%CI: 0.68-5.51). Of 341 patients, cases (n = 22) and controls (n = 319), high adherence level (≥ 80%) to allopurinol therapy, compared with lower adherence level (< 80%), was associated with a lower rate of ESRD onset (RR = 0.35; 95%CI: 0.13-0.91).

CONCLUSION

Gout control seem to be associated with a significant decreased risk of ESRD onset in hypertensive populations, further research should be conducted confirming this potential associated risk.

Clinical Study on efficacy of allopurinol in patients with acute coronary syndrome and its functional mechanism

OBJECTIVE

To investigate the therapeutic effect of allopurinol treatment on acute coronary syndrome and to elucidate its possible mechanism.

METHODS

Patients with acute coronary syndrome (n = 100) were recruited as research subjects in our hospital. The patients were randomly divided into two groups, an allopurinol group (n = 50) and a control group (n = 50). These two groups were treated with conventional antiplatelet, anticoagulation and anti-ischemic therapy; allopurinol therapy was added to the allopurinol group based on conventional treatment indications. Biochemical markers such as serum creatinine, uric acid, BNP, blood glucose and blood lipid were compared between the two groups. Indicators of oxidative stress and inflammatory response (MDA, OX-LDL, NO, hs-CRP and TNF-α), as well as cardiovascular events during 2-years follow-up, were recorded.

RESULTS

On admission, there was no difference in serum creatinine, uric acid, BNP, blood glucose or lipid levels between the two groups (P > 0.05). However, after 1 month of treatment, these levels were improved in patients in the allopurinol group compared to the control group (P < 0.05). MDA, OX-LDL, hs-CRP and TNF-α decreased after treatment periods of 14 days and 1 month. They were also decreased at 3 month, 6 month, 1 year, and 2 year follow-up visits. However, data from the allopurinol group demonstrated significantly lower levels than in the control group (P < 0.05). Additionally, compared with the control group, allopurinol treatment significantly elevated the level of NO (P < 0.05). The total effective rates of the allopurinol group are much higher than in the control group for both angina pectoris (93.2% and 76%, respectively) and ECG (96% and 82%, respectively). Most patients in the allopurinol group (n = 40) and the control group (n = 41) received stent implantation with no significant difference shown between them. The incidence of cardiovascular events during 2 years of follow-up in the allopurinol group was 10%; it was 30% in the control group.

CONCLUSION

Allopurinol has a remarkable effect in the treatment of ACS and can improve the oxidative stress and inflammatory reaction indicators of patients. The protective mechanism of allopurinol might be achieved by suppressing the secretion and release of inflammatory mediators such as TNF-α, hs-CRP, OX-LDL and MDA while increasing levels of NO.

Drug therapies to delay the progression of chronic kidney disease

Chronic kidney disease (CKD) is associated with significant morbidity and mortality, impacted not alone by progression to end-stage kidney disease, but also by the high associated incidence of cardiovascular events and related mortality. Despite our current understanding of the pathogenesis of CKD and the treatments available, the reported incidence of CKD continues to rise worldwide, and is often referred to as the silent public healthcare epidemic. The significant cost to patient wellbeing and to the economy of managing the later stages of CKD have prompted efforts to develop interventions to delay the development and progression of this syndrome. In this article, we review established and novel agents that may aid in delaying the progression of CKD and improve patient outcomes.

Switching from allopurinol to febuxostat: efficacy and tolerability in hemodialysis patients

Background

Febuxostat is a novel xanthine oxidase inhibitor. However, few studies have examined the long-term efficacy and tolerability of febuxostat after switching from allopurinol in hemodialysis (HD) patients. Therefore, the present study evaluated the long-term efficacy and tolerability of febuxostat in HD patients after switching from allopurinol.

Findings

We monitored the levels of hemoglobin, hematocrit, platelet count, blood urea nitrogen, serum creatinine, serum sodium, serum potassium, serum chloride, serum calcium, serum inorganic phosphorus, aspartate transaminase, alanine aminotransferase, alkaline phosphatase, lactate dehydrogenase, and total protein that were considered overall as a tolerability index, while the serum uric acid (UA) level was considered an index of efficacy. All values were measured at baseline and at 1, 6, 12, and 16 months after the switch to febuxostat therapy. All subjects switched from allopurinol (100 mg/day) to febuxostat (10 mg/day) in August 2013. Clinical laboratory data were collected at baseline in July 2013 until December 2014. Nine patients were included in the study analysis. Results showed that clinical laboratory data at baseline versus those at 16 months were not significantly different. Serum UA levels, which represented the efficacy index, were significantly different between the baseline level (6.8 ± 1.4) and those at 1, 6, 12, and 16 months (5.2 ± 1.1, 5.1 ± 1.1, 4.6 ± 0.9, and 5.4 ± 1.8 mg/dL, respectively; all p < 0.05).

Conclusion

Switching from allopurinol to febuxostat in HD patients reduced serum UA levels, with no changes in other clinical laboratory data in the long term.