Serum Uric Acid as a Risk Factor for Chronic Kidney Disease in a Japanese Community - The Hisayama Study

Comparison of the incidence of proteinuria and changes in eGFR among febuxostat and topiroxostat users

BACKGROUND

Febuxostat and topiroxostat are non-purine selective xanthine oxidoreductase inhibitors commonly used for hyperuricaemia treatment in Japan. However, comparative data on the effects of febuxostat and topiroxostat on renal function and proteinuria are limited. This study compared proteinuria incidence and changes in the estimated glomerular filtration rate (eGFR) among prevalent febuxostat and topiroxostat users.

METHODS

We conducted a retrospective cohort study using databases provided by DeSC Healthcare, Inc. (Tokyo, Japan). We identified 17,446 individuals (11.8% women; mean age 67.4 years) with eGFR ≥ 30 mL/min/1.73 m2 and no history of cardiovascular disease or proteinuria at baseline. Separate analyses were performed for individuals with eGFR < 60 mL/min/1.73 m2 and those with eGFR ≥ 60 mL/min/1.73 m2. The adjusted hazard ratio (HR) for proteinuria incidence in topiroxostat users compared with febuxostat users was assessed using the Cox model. Changes in eGFR were compared between the two groups using multiple regression analysis.

RESULTS

During the mean follow-up period of 1.79 years, 1,433 participants developed proteinuria. In non-diabetic individuals with eGFR ≥ 60 mL/min/1.73 m2, the adjusted HR for proteinuria incidence in topiroxostat users compared with febuxostat users was 0.60 (95% confidence interval, 0.40-0.91; p = 0.016). No significant differences were observed in eGFR changes between the two groups with eGFR < 60 and ≥ 60 mL/min/1.73 m2.

CONCLUSION

Topiroxostat prevalent users had a lower risk of proteinuria than febuxostat prevalent users in non-diabetic individuals with eGFR ≥ 60 mL/min/1.73 m2. Our findings suggest that topiroxostat might be more effective than febuxostat in preventing proteinuria in non-diabetic individuals with eGFR ≥ 60 mL/min/1.73 m2.

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.

Serum uric acid is associated with chronic kidney disease in elderly Chinese patients with diabetes

BACKGROUND

The relationship between hyperuricemia and chronic kidney disease (CKD) has been investigated extensively. However, studies on elderly individuals are still limited. Moreover, there is no consensus on whether hyperuricemia or elevated serum uric acid (SUA) within the normal range is correlated with the new onset of CKD and whether there are differences between males and females.

METHODS

We included 39039 elderly diabetic patients without CKD at baseline from a community-based cohort in Wuhan, China. The outcome event was the new onset of CKD (defined as an estimated glomerular filtration rate < 60 mL/min/1.73 m2). Multivariate Cox models were used to assess the adjusted hazard ratio (HR).

RESULTS

During the 2-year follow-up period, 3162 (8.10%) patients with diabetes developed new-onset CKD. The optimal cutoff value of SUA for incident CKD was 347.4 μmol/L. The adjusted HRs of hyperuricemia for new-onset CKD were 1.925 (1.724-2.150) and 1.676 (1.520-1.848) for males and females, respectively. The risk of developing CKD increased across the Q4 group up to 2.242 times for their counterparts in the lowest SUA quartile, independent of age, sex, diabetes duration, obesity, hypertension, systolic blood pressure, diastolic blood pressure, smoking, drinking, dyslipidemia, triglyceride, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and fasting plasma glucose.

CONCLUSIONS

Hyperuricemia is an independent predictor of incident CKD. Elevated SUA was linearly correlated with CKD in elderly patients with diabetes, showing a relatively higher intensity among males compared with that among females. The optimal cutoff value of SUA for the risk of new-onset CKD in elderly patients with diabetes was 347.4 μmol/L.

Sex differences in the association between urate metabolism and kidney outcomes in patients with chronic kidney disease

BACKGROUND

The association between serum uric acid (SUA) concentration and kidney outcomes in patients with chronic kidney disease (CKD) is controversial. Furthermore, there are no reports regarding the association of clearance of uric acid (CUA) with kidney outcomes. We aimed to determine whether SUA or CUA was associated with kidney outcomes in patients with CKD stratified by sex.

METHODS

The present prospective study was conducted in 815 patients (523 men and 292 women) with CKD. The participants were divided into quartiles (Q1-Q4) of SUA or CUA for each sex. Endpoints were defined as a composite of doubling of serum creatinine (SCr), end-stage kidney disease (ESKD), or death (outcome 1) and a composite of doubling of SCr or ESKD (outcome 2).

RESULTS

During a median follow-up of 2.5 years, outcomes 1 and 2 occurred in 363 and 321 patients, respectively. Multivariable-adjusted Cox analyses showed that in men, the hazard ratios (95% confidence intervals) for outcome 1 of Q1, Q2, and Q3 of CUA were 2.08 (1.18-3.70), 2.03 (1.22-3.39), and 1.85 (1.17-2.95), respectively, compared with Q4. Additionally, there were similar associations between lower CUA quartiles and outcome 2 in men. However, no associations between SUA and either outcome were observed in men. Conversely, in women, neither SUA nor CUA was associated with an outcome.

CONCLUSION

In CKD, lower CUA was independently associated with poor kidney outcomes only in men, and in both sexes, there was no association of SUA with kidney outcomes.

Association of blood pressure and hyperuricemia with proteinuria and reduced renal function in the general population

This study aimed to investigate the effect of hyperuricemia (HU) on the association of systolic blood pressure (SBP) with the prevalence of proteinuria and low estimated glomerular filtration rate (eGFR) in the general population. This cross-sectional study enrolled 24,728 Japanese individuals (11,137 men and 13,591 women) who underwent health checkups in 2010. The prevalence of proteinuria and low eGFR (< 60 mL/min/1.73 m2) among participants classified according to serum uric acid levels and SBP was compared. HU was defined as serum uric acid levels higher than the 75th percentile in male and female participants (> 7.2 and > 5.4 mg/dL, respectively). The odds ratio (OR) for proteinuria increased with elevated SBP. This trend was significantly evident in participants with HU. Moreover, there was an interactive effect of SBP and HU on the prevalence of proteinuria in the male (Pfor interaction = 0.04) and female (Pfor interaction = 0.04) participants. Next, we evaluated the OR for low eGFR (< 60 mL/min/1.73 m2) with and without proteinuria based on the presence of HU. The multivariate analysis revealed that the OR for low eGFR with proteinuria increased with elevated SBP, but that for low eGFR without proteinuria decreased. These trends of OR tended to be prevalent among those with HU. The association between SBP and the prevalence of proteinuria was more pronounced in participants with HU. However, the association between SBP and decreased renal function with and without proteinuria might be different regardless of HU.

Lower range of serum uric acid level increases risk of rapid decline of kidney function in young and middle-aged adults: the Yuport Medical Checkup Center Study

BACKGROUND

The effect of low serum uric acid (sUA) levels on kidney function is unclear. This study aimed to clarify the relationship between low sUA levels and the rapid decline in kidney function.

METHODS

We examined the relationship between sUA levels and kidney function decline in health check-up examinees. A total of 10,547 participants were enrolled using data from the Yuport Medical Checkup Center Study between 1998 and 2002 for baseline and data from 2002 to 2006 as the follow-up period in Japan. According to sUA level (mg/dL), we classified the participants into the following six groups: (1) 2.0-2.9 (n = 247), (2) 3.0-3.9 (n = 1457), (3) 4.0-4.9 (n = 2883), (4) 5.0-5.9 (n = 2899), (5) 6.0-6.9 (n = 2010), and (6) 7.0-7.9 (n = 1,051). The relationship between sUA level and rapid decline in estimated glomerular filtration rate (ΔeGFR ≥ 3 mL/min/1.73 m²/year) was examined using a logistic regression model.

RESULTS

During study period (5.4 ± 1.6 years), the incidence of rapid eGFR decline for the respective sUA groups (2.0-2.9, 3.0-3.9, 4.0-4.9, 5.0-5.9, 6.0-6.9, 7.0-7.9) were as follows: 4.5%, 4.0%, 2.4%, 3.3%, 3.1%, 3.4%. The crude and adjusted odds ratios (OR) for rapid eGFR decline were significantly higher in the 2.0-2.9 (OR:1.93 and 1.86) and 3.0-3.9 (OR:1.72 and 1.73) groups than in the 4.0-4.9 groups (reference). Stratified analysis of age differences revealed that the detrimental effect of low sUA was not evident in older adults (age ≥ 65 years).

CONCLUSION

A lower normal sUA level is related to an increased risk for a rapid decline in kidney function.

The association among uric acid, microalbumin and estimated glomerular filtration rate in hypertensive patients: a case control study

OBJECTIVE

To estimate the relationship among uric acid (UA), 24-h microalbumin (24 h-MAU) and estimated glomerular filtration rate (eGFR) in hypertensive patients.

METHOD

The study enrolled adult patients hospitalized in TEDA International Cardiovascular Hospital. The study was used to explore the correlation among UA, 24 h-MAU and eGFR. Univariate analysis was used to compare continuous or categorical data groups according to data type. Multivariate analysis was used to explore the correlation among UA, Log 24 h-MAU and eGFR by linear regression, and the relationship among UA, 24 h-MAU ≥ 30 mg/24 h (increased 24 h-MAU) and eGFR < 90 ml·min^-1·1.73 m^-2 (mildly decreased eGFR) by logistic regression. Mediation effect analysis was used to explore the mediating effect of increased 24 h-MAU between UA and mildly decreased eGFR. Subgroup analysis was used to investigate the correlation among UA, 24 h-MAU and eGFR in different gender.

RESULT

Seven hundred and thirty-three inpatients were enrolled in the study, including 257 patients with hyperuricemia. The level of UA was 377.8 ± 99.9 μmol/L in all patients enrolled, and it was about 50.1% higher in hyperuricemia group (482.3 ± 58.8 μmol/L vs. 321.4 ± 63.5 μmol/L, P < 0.001). The prevalence of hyperuricemia was 35.1% (95%CI 31.6-38.5%). The univariate regression analysis showed that UA was significant related to Log 24 h-MAU, increased 24 h-MAU, eGFR and mildly decreased eGFR. After adjusted confounding factors, UA was significant related to Log 24 h-MAU (β = 0.163, P < 0.001), eGFR (β = - 0.196, P < 0.001), increased 24 h-MAU (quantitative analysis: OR = 1.045, 95%CI 1.020-1.071, P < 0.001; qualitative analysis: OR = 2.245, 95%CI 1.410-3.572, P = 0.001), but had no significant relationship with mildly decreased eGFR. Mediating effect analysis showed that increased 24 h-MAU partially mediated the relationship between UA and mildly decreased eGFR (relative indirect effect: 25.0% and 20.3% in quantitative analysis and qualitative analysis respectively). In the subgroup analysis, the results were stable and similar to the analysis for entry patients.

CONCLUSION

The prevalence of hyperuricemia was higher in hypertensive inpatients. UA was strongly associated with Log 24 h-MAU, eGFR and increased 24 h-MAU, while the correlation with mildly decreased eGFR was affected by multiple factors. And increased 24 h-MAU might be the intermediate factor between UA and mildly decreased eGFR.

Sodium-glucose cotransporter 2 inhibitors as the first universal treatment of chronic kidney disease

In the last five years, the medical community was astonishingly surprised by the sequential large outcome trials that displayed the renal effects of sodium glucose co-transporter inhibitors (SGLT2Is) in type 2 diabetes mellitus (T2DM) patients with or without chronic kidney disease (CKD). This favorable effect was later disclosed in non-diabetic CKD patients. The EMPA-REG OUTCOME trial was the first trial that showed a reduction for the need for dialysis in patients suffering diabetic kidney disease (DKD) by 55%. This figure is double the score achieved by the angiotensin receptor blocker, Losartan, in RENAAL trial. The need for dialysis in DAPA-CKD trial was reduced in diabetic and non-diabetic CKD patients by 33%. The renal-specific composite outcome was reduced by 39% in EMPA-REG trial, 40% in CANVAS study, 47% in DECLARE-TIMI 58 study, 34% in CREDENCE trial, and 44% in DAPA-CKD trial. The greater surprise is the significant favorable effect of SGLT2Is on overall mortality in CKD patients with or without T2DM. Similar survival benefit was not previously encountered with any of the medications used in CKD patients with or without diabetes. In this review, we disclose the results of the DAPA-CKD trial, the CREDENCE trial and those of several cardiovascular outcome trials (CVOT) that used different SGLT2Is and showed that patients with lower eGFR levels may have greater benefit with respect to cardiovascular morbidity than patients with normal kidney function. In addition, we discuss the different mechanisms of action that explain the renal beneficial effects of SGLT2Is.

Hyperuricemia—a serious complication among patients with chronic kidney disease: a systematic review and meta-analysis

Aim: Hyperuricemia as a putative risk factor for chronic kidney disease (CKD) progression remains controversial and debatable. This systematic review aims to explore the prevalence of hyperuricemia among CKD patients worldwide. Methods: This study was conducted in accordance with the Meta-analysis Of Observational Studies in Epidemiology (MOOSE) guidelines by using the existing literature from online databases such as MEDLINE/PubMed, ScienceDirect, Google Scholar, Cochrane library and grey literature. The effect size with corresponding 95% confidence interval (CI) was calculated to assess the pooled prevalence of hyperuricemia in chronic kidney patients. The subgroup analysis based on gender and geography was also carried out by utilizing comprehensive meta-analysis, version 2.0. Results: Twenty-three studies containing 212,740 participants were eligible for quantitative synthesis. The pooled prevalence of 43.6% (35.2–52.4%) hyperuricemia was reported in patients with CKD globally. In India, 38.4% of prevalence was observed. The gender specific prevalence (9 studies) was reported as 67.4% (60.9–73.3%) in case of male patients and 32.6% (26.7–39.1%) in female patients with 95% CI. Conclusions: The prevalence of hyperuricemia was reported to be reasonably high among CKD patients worldwide. During the management of CKD, this high prevalence demands more prudent attention for this clinical complication which possibly can lead to positive renal outcomes.

Hyperuricemia is associated with all-cause mortality among males and females: Findings from a study on Japanese community-dwelling individuals

Background

Serum uric acid (SUA) is a key determinant of cardiovascular diseases (CVDs). Studies have also shown that SUA independently impacts age-related health outcomes, although their findings differ between males and females. Furthermore, predictive data on all-cause mortality remain limited, particularly for the Japanese population. Thus, this study examined the association between SUA and survival prognosis among males and females based on a follow-up period of 7 or 19 years.

Methods

The study was based on 1,573 male (63 ± 14 years) and 1,980 female (65 ± 12 years) participants who participated in a Nomura Cohort Study in 2002 (Cohort 1) and 2014 (Cohort 2), and continued throughout the follow-up period. A basic resident register was referenced to derive the adjusted relative risk estimates for all-cause mortality. Finally, a Cox proportional hazards model analysis was conducted and was adjusted for possible confounders to estimate hazard ratios (HRs). 95% confidence intervals (CIs) were computed separately for male and female participants.

Results

Of the total 3,553 participants, 905 (25.5%) were deceased. Of these, 473 were male (30.1% of all males) and 432 were female (21.8% of all females). Hyperuricemia was defined in males with SUA levels of 8.5 mg/dL or higher, and in females with SUA levels of 7.5 mg/dL or higher, and was associated with a significantly increased HR for all-cause mortality (males: 1.67; 95% CI: 1.06-2.63; females: 2.17; 95% CI: 1.20-3.94). The data were further stratified based on age (< 65 years or ≥ 65 years), body mass index (BMI) (< 25.0 kg/m2 or ≥ 25.0 kg/m2), History of cardiovascular disease, estimated glomerular filtration rate (< 60 mL/min/1.73 m2 or ≥ 60 mL/min/1.73 m2), and presence of SUA-lowering medication. All stratified groups demonstrated a similar trend. The hyperuricemia group in particular reported a significant increase in HR. On the other hand, a U-shaped increase in HR was observed in those with BMI greater than 25 kg/m2 and SUA-lowering medication, but interaction effect was not significant.

Conclusions

Hyperuricemia is a key risk indicator for all-cause mortality in male and female community-dwelling individuals in Japan.

A systematic review and meta-analysis of the association between uric acid levels and chronic kidney disease

The function of uric acid (UA) in the genesis and evolution of chronic kidney disease (CKD) has motivated numerous studies, but the results remain inconclusive. We sought to conduct a systematic review and meta-analysis of cohort studies aiming to analyze the association of UA levels with the incidence and progression of CKD. Pubmed/Medline, Lilacs/Bireme and Web of Science were searched to identify eligible studies, following the PRISMA protocol. Data were presented for CKD incidence and progression separately. For the meta-analysis, studies with data stratified by subgroups according to serum UA levels were selected. The inverse variance-weighted random effects model was used to generate a combined effect estimate. Meta-regressions were performed to identify the causes of heterogeneity. The Newcastle-Ottawa Scale was used to assess the risk of bias. The publication bias was tested by funnel plot and Egger's test. Eighteen CKD incidence studies (n = 398,663) and six CKD progression studies (n = 13,575) were included. An inverse relationship was observed between UA levels and protection from CKD incidence and progression. Lower UA levels were protective for the risk of CKD incidence (RR 0.65 [95% CI 0.56-0.75]) and progression (RR 0.55 [95% CI 0.44-0.68]). UA seems to be implicated both in the genesis of CKD and its evolution.

The Active Components of Sunflower (Helianthus annuus L.) Calathide and the Effects on Urate Nephropathy Based on COX-2/PGE2 Signaling Pathway and the Urate Transporter URAT1, ABCG2, and GLUT9

The sunflower (Helianthus annuus L.) calathide is gradually used as an alternative treatment for hyperuricemia; nevertheless, evidence regarding its main components and therapeutic capacity for urate nephropathy is lacking. Identification of sunflower calathide aqueous extract (SCE) was rapidly done by UPLC-ESI-Q-Orbitrap, and 32 water-soluble compounds with a comprehensive score >80 were discovered. Besides, yeast extract was administrated to induce high UA levels and hyperuricemic renal injury. We found that SCE treatment not only decreased UA levels to a comparable degree as allopurinol and benzbromarone, but also reduced the BUN levels and participated in kidney injury repair induced by uric acid. Moreover, it regulated the expression of URAT1 and ABCG2, especially inhibiting the GLUT9 in the normal kidney. Results were multifacetedly evaluated with a view to suggesting a possible mechanism of action as compared with those of allopurinol and benzbromarone by western blotting, H&E staining, and immunohistochemistry. However, the H&E staining showed histological changes in model, benzbromarone, and allopurinol groups rather than SCE treatments, and at the same time, the uric acid was identified as a cause of renal damage. The antiinflammatory effects and the regulations of COX-2/PGE2 signaling pathway were revealed on the LPS-induced RAW264.7 cells, indicating that the SCE not only increased cellular proliferation but also downregulated the COX-2, PGE2, NO, and IFN-γ cytokines in the RAW264.7 cells. To conclude, the SCE acts on urate transporters and contributes to prevent urate nephropathy via alleviating inflammatory process involving COX-2/PGE2 signaling pathway. It is available to develop SCE as food supplemental applications for hyperuricemia and nephritic inflammation.

Efficacy of Chinese herbal medicine Jiangniaosuan formula for treatment of hyperuricemia: study protocol for a double-blinded non-inferiority randomized controlled clinical trial

BACKGROUND

Jiangniaosuan formula (JNSF) is commonly used in China for treating hyperuricemia, but there is little research-based evidence to support its use. This randomized controlled trial aims to assess the efficacy and safety of JNSF.

METHODS

A total of 72 patients with hyperuricemia will be selected and randomly assigned in a ratio of 1:2 to receive either Western medicine, i.e., febuxostat 40 mg (WG group; n = 24), or Chinese herbal medicine, i.e., Jiangniaosuan formula + febuxostat 20 mg (WJNSG group; n = 48). After 12 weeks, the WJNSG will be randomly divided into two groups of 24 patients each; one group (WJNSG; n = 24) still will receive febuxostat 20 mg + Jiangniaosuan formula, and the other group (JNSG; n = 24) will continue to receive Jiangniaosuan formula + placebo. Participants will be followed up at 4-week intervals. The primary outcome will be the change in serum uric acid level, and the secondary outcome will be the change in traditional Chinese medicine (TCM) syndrome scores. Serum creatinine, blood glucose, and insulin levels will also be measured.

DISCUSSION

We hypothesize that patients with hyperuricemia will benefit from JNSF. This study will provide evidence-based recommendations for clinicians.

DISSEMINATION

The results will be published in a peer-reviewed journal and disseminated by academic conferences. The datasets analyzed during the current study are available from the corresponding author on reasonable request.

TRIAL REGISTRATION

Chinese Clinical Trials Register ChiCTR2000041083 . Registered on 3 May 2021. The protocol version number is V3.0, 20210301.

Relationship between serum uric acid levels and the incidence of cardiovascular events after percutaneous coronary intervention

BACKGROUND

The role of serum uric acid (SUA) as an independent risk factor for coronary artery disease remains unclear. The aim of this study was to investigate whether the SUA levels could affect the incidence of major adverse cardiac events (MACE) after percutaneous coronary intervention (PCI).

METHODS AND RESULTS

We retrospectively examined the clinical records of 1,949 patients who underwent successful PCI. First, they were divided into two groups based on an SUA level of 7.0mg/dl. Among the two groups, the incidence of MACE was measured for a maximum of 5 years after PCI. Next, we divided them into 6 groups at SUA intervals of 1.0mg/dl and estimated the hazard ratios of each group. The Kaplan-Meier curve demonstrated that patients with SUA levels of >7.0mg/dl had a higher incidence of MACE than those with 7.0mg/dl or less. However, according to the multivariate analysis, the SUA level was not significantly correlated with the incidence of MACE because other factors could strongly affect it. Meanwhile, the group with SUA levels between 4.1-5.0mg/dl had a lower hazard ratio compared to groups with SUA levels of more than 5.1mg/dl. However, the hazard ratio of the group with SUA levels of 4.0mg or less was not lower than that of the group with SUA levels of 4.1-5.0mg/dl. Even after adjustment for several parameters, nearly the same results before adjustment were obtained for the hazard ratios of each group.

CONCLUSION

The present study demonstrated that the SUA level was one of the most valuable predictors of cardiovascular events after PCI, with elevated SUA levels adversely affecting secondary prevention.

Sodium-glucose cotransporter 2 inhibitors as the first universal treatment of chronic kidney disease

In the last five years, the medical community was astonishingly surprised by the sequential large outcome trials that displayed the renal effects of sodium glucose co-transporter inhibitors (SGLT2Is) in type 2 diabetes mellitus (T2DM) patients with or without chronic kidney disease (CKD). This favorable effect was later disclosed in non-diabetic CKD patients. The EMPA-REG OUTCOME trial was the first trial that showed a reduction for the need for dialysis in patients suffering diabetic kidney disease (DKD) by 55%. This figure is double the score achieved by the angiotensin receptor blocker, Losartan, in RENAAL trial. The need for dialysis in DAPA-CKD trial was reduced in diabetic and non-diabetic CKD patients by 33%. The renal-specific composite outcome was reduced by 39% in EMPA-REG trial, 40% in CANVAS study, 47% in DECLARE-TIMI 58 study, 34% in CREDENCE trial, and 44% in DAPA-CKD trial. The greater surprise is the significant favorable effect of SGLT2Is on overall mortality in CKD patients with or without T2DM. Similar survival benefit was not previously encountered with any of the medications used in CKD patients with or without diabetes. In this review, we disclose the results of the DAPA-CKD trial, the CREDENCE trial and those of several cardiovascular outcome trials (CVOT) that used different SGLT2Is and showed that patients with lower eGFR levels may have greater benefit with respect to cardiovascular morbidity than patients with normal kidney function. In addition, we discuss the different mechanisms of action that explain the renal beneficial effects of SGLT2Is.

Detailed association between serum uric acid levels and the incidence of chronic kidney disease stratified by sex in middle-aged adults

BACKGROUND AND AIMS

Chronic kidney disease (CKD) is a global health burden. Previous studies have shown a J- or U-shaped association between serum uric acid (SUA) and cardiovascular mortality. We assessed the risk of CKD incidence in a refined SUA category in middle-aged adults stratified by sex.

METHODS

We analyzed data from 138,511 participants <65 years old (29.6% women; mean age 44.1 years) without CKD at baseline acquired from the JMDC database. The Cox model was used to assess the adjusted hazard ratio (HR).

RESULTS

During the mean follow-up period of 4.68 years, 12,589 participants developed CKD. The fully adjusted HRs (95% confidence interval [CI], p-value) for CKD incidence in men with SUA <4.0, 10.0-10.9 and ≥ 11.0 mg/dL compared to men with SUA 4.0-4.9 mg/dL were 1.13 (1.01-1.26, p = 0.030), 1.98 (1.32-2.97, p = 0.0010), and 3.74 (1.68-8.35, p = 0.0013), respectively. The fully adjusted HRs for CKD incidence in women with SUA <4.0, 8.0-8.9, and ≥9.0 mg/dL compared to women with SUA 4.0-4.9 mg/dL were 1.08 (1.01-1.16, p = 0.032), 2.39 (1.07-5.35, p = 0.034), and 3.20 (0.80-12.8, p = 0.10), respectively.

CONCLUSIONS

Both high and low SUA levels were identified as risk factors for CKD incidence in middle-aged men and women. The association of SUA levels with the increase in the risk of CKD incidence differed by sex, and the range of SUA levels associated with an increase in the risk of CKD incidence varied by sex.

The Pattern of Allopurinol Prescription Among Chronic Kidney Disease Patients in a Tertiary Care Centre: A Single-Centre Experience

Context

Hyperuricemia is prevalent in patients with chronic kidney disease (CKD). Although it is associated with CKD incidence and progression, treating asymptomatic hyperuricemia with uric acid-lowering agents is still debatable.

Aim of Work

determine the rate of non-classical prescription of allopurinol in CKD patients.

Settings and Design

This was a retrospective study of adult patients prescribed allopurinol with CKD (stages 2–5) in Doctor Soliman Fakeeh Hospital (DSFH) Jeddah, Saudi Arabia, from 1/1/2016 to 1/1/2017.

Subjects and Methods

Eligible patients were identified from the hospital’s pharmacy system and cross-referenced with the electronic health records. Demographic data, laboratory results and indication as recorded by the prescribing physician were extracted. Prescriptions with no indication were categorized based on the uric acid levels. Hyperuricemia was documented as mild (6–10 mg/dL in females and 7–13 mg/dL in males) and severe (>13mg/dL in men and >10mg/dL in women).

Statistical Analysis Used

Descriptive statistics (frequencies, percentages).

Results

From the 594 identified patients, 464 (78.1%) were males. A third of prescriptions (209/594) had no indication, 43.5% of which (91/209) had no documented uric acid levels, and 16.3% (34/209) had normal levels. Including patients with undocumented indication, 64.2% (381/594) were prescribed allopurinol for hyperuricemia, 86.4% of which (329/381) had mild hyperuricemia, and only 13.6% (52/381) had severe hyperuricemia. Other indications included malignancy-related disorders (6.2%, 37/594), gouty arthritis (5.2%, 31/594), and stones of unknown aetiology (3.4%, 20/594).

Conclusion

The percentage of allopurinol prescription to patients with CKD without a clear indication in our centre was markedly high. This might increase the risk for side effects with no evidence-based benefits.

Increased Uric Acid, Gamma-Glutamyl Transpeptidase and Alkaline Phosphatase in Early-Pregnancy Associated With the Development of Gestational Hypertension and Preeclampsia

Background: Previous studies have reported that biomarkers of liver injury and renal dysfunction were associated with hypertensive disorders of pregnancy (HDP). However, the associations of these biomarkers in early pregnancy with the risk of HDP and longitudinal blood pressure pattern during pregnancy were rarely investigated in prospective cohort studies. Methods: A total of 1,041 pregnant women were enrolled in this prospective cohort study. BP was assessed in four stages throughout pregnancy. The following biomarkers were measured at early pregnancy before 18 weeks gestation: lactate dehydrogenase (LDH), aspartate aminotransferase to alanine aminotransferase ratio (AST/ALT), gamma-glutamyl transpeptidase (GGT), alkaline phosphatase (ALP), uric acid (UA), and estimated glomerular filtration rate (eGFR). Linear mixed-effects and logistic regression models were used to examine the associations of these biomarkers with longitudinal BP pattern during pregnancy and HDP incidence, respectively. Results: In unadjusted models, higher serum UA, GGT, ALP, and LDH levels, as well as lower eGFR and AST/ALT, were associated with higher BP levels during pregnancy and an increased risk of HDP. After adjustment for maternal age, pre-pregnancy BMI and other potential confounders, UA, GGT, ALP, and LDH remained positively associated with both BP and HDP. However, eGFR and AST/ALT were not associated with HDP after adjusting for potential confounders. When including all 6 biomarkers simultaneously in multivariable analyses, increased UA, GGT, and ALP significantly associated with gestational hypertension and preeclampsia. Conclusion: This study suggests that increased UA, GGT, and ALP in early-pregnancy are independent risk factors of gestational hypertension and preeclampsia.

[Asymptomatic Hyperuricemia and Risk Of Cardiovascular and Renal Diseases]

Asymptomatic hyperuricemia (HU) is common in the population and significantly contributes to the general cardiovascular risk. Despite extensive study of this condition there is still no conclusive answers to questions about detection of asymptomatic HU and its effect on the risk for development and progression of cardiovascular and kidney diseases. This review summarizes key information about these issues, which has been accumulated by the present time.

U-shaped relationship between serum uric acid level and decline in renal function during a 10-year period in female subjects: BOREAS-CKD2

While hyperuricemia is recognized as a risk factor for chronic kidney disease (CKD), the risk of CKD in subjects with a low level of serum uric acid (UA) remains controversial. Here, we examined whether the association of CKD risk with serum UA level differs depending on the sex and age of subjects in a general population. Of subjects who received annual health checkups, we enrolled 6,779 subjects (male/female: 4,454/2,325; age: 45 ± 9 years) with data from a 10-year follow-up after excluding subjects taking anti-hyperuricemic drugs and those with CKD at baseline. During the follow-up period, 11.4% of the males and 11.7% of the females developed CKD. A significant interaction of sex, but not age, with the effect of baseline UA level on CKD risk was found. A restricted cubic spline analysis showed a U-shaped association of the baseline UA level with the risk of CKD in females. Multivariable Cox proportional hazard analyses for females showed that baseline UA levels in the 5th quintile (Q5, ≥5 mg/dL; HR: 1.68) and the 1st quintile (Q1, ≤3.5 mg/dL; HR: 1.73) were independent risk factors for CKD when compared with UA levels in the 4th quintile (Q4, 4.5-4.9 mg/dL). In males, restricted cubic spline analysis indicated increased CKD risk in subjects with a higher baseline UA level but not in those with a low UA level. In conclusion, a low UA level is a significant risk factor for CKD in females, while an elevated UA level increases the risk of CKD in both sexes.

Serum cystatin C levels are decreased in type 1 diabetes mellitus patients with diabetic ketoacidosis

BACKGROUND

Cystatin C is a marker of renal function and risk factor for cardiovascular disease. Patients with acute myocardial infarction showed a significant decrease in cystatin C levels. It is unknown whether reduced serum cystatin C levels are connected to acute events or represent a negative acute phase response. The current study aimed to assess the association between cystatin C and the existence of diabetic ketoacidosis (DKA), an acute event in individuals with type 1 diabetes mellitus (T1DM).

METHODS

Cystatin C was measured in the control group (N.=322) and in T1DM patients with (N.=161) and without DKA (N.=146). Data were compared according to diabetes and ketoacidosis status. Correlation analysis was used to identify factors associated with cystatin C levels. A multiple stepwise regression analysis was used to determine which of the parameters that were significantly correlated with cystatin C in univariate analysis were independently related to cystatin C. Then, we assessed the independent association between cystatin C and the occurrence of DKA in T1DM patients.

RESULTS

Serum cystatin C levels were lower in patients with DKA than in patients without DKA. After adjustment for age, sex, fasting plasma glucose and creatinine, cystatin C was positively correlated with the duration of diabetes, systolic blood pressure (SBP), total cholesterol, triglycerides, uric acid and low-density lipoprotein cholesterol (P=0.004, P=0.022, P=0.013, P=0.035, P=0.006, P=0.012, respectively) and negatively correlated with hemoglobin (P<0.001). The duration of diabetes (P<0.001), total cholesterol (P=0.002), hemoglobin (P<0.001), SBP (P=0.011) and serum creatinine (P<0.001) were independently associated with cystatin C. Furthermore, we found that cystatin C was independently associated with the occurrence of DKA in T1DM patients (OR=0.004, 95% CI: 0.000-0.079, P<0.001).

CONCLUSIONS

Cystatin C was decreased in T1DM patients with DKA and was found to be an independent predictor of the occurrence of DKA in T1DM patients. The reduction in cystatin C levels might be significantly connected with acute events.

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).

Uric acid in CKD: has the jury come to the verdict?

Epidemiological studies show that hyperuricemia independently predicts the development of chronic kidney disease (CKD) in individuals with normal kidney function both in the general population and in subjects with diabetes. As a matter of fact, an unfavorable role of uric acid may somewhat be harder to identify in the context of multiple risk factors and pathogenetic mechanisms typical of overt CKD such as proteinuria and high blood pressure. Although the discrepancy in clinical results could mean that urate lowering treatment does not provide a constant benefit in all patients with hyperuricemia and CKD, we believe that the inconsistency in the results from available meta-analysis is mainly due to inadequate sample size, short follow-up times and heterogeneity in study design characterizing the randomized controlled trials included in the analyses. Therefore, available data support the view that hyperuricemia has a damaging impact on kidney function, while preliminary evidence suggests that treatment of so-called asymptomatic hyperuricemia may be helpful to slow or delay the progression of chronic kidney.

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

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

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

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

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

Higher serum uric acid level is inversely associated with renal function assessed by cystatin C in a Japanese general population without chronic kidney disease: the KOBE study

Background

Although several epidemiological studies have suggested that high serum uric acid (SUA) levels are related to a decline in kidney function, only a few studies have investigated using cystatin C to calculate estimated glomerular filtration rate (eGFR). We aimed to clarify the relationship between SUA levels and kidney function assessed by cystatin C in a Japanese general community population without chronic kidney disease (CKD).

Methods

We conducted a community-based cross-sectional study that included 1086 healthy participants, aged 40–74 years, without CKD and not undergoing treatment of hyperuricemia, who had participated in the baseline survey of the Kobe Orthopedic and Biomedical Epidemiological (KOBE) study. The preconditions for participation in this study were no past histories of cardiovascular disease or cancer, and not undergoing treatment for diabetes, hypertension, or dyslipidemia. We classified the participants into quartiles stratified by sex according to their SUA level and then examined the relationship with eGFR. The odds ratios for having a low eGFR, defined as the lowest quartile of eGFR (i.e., ≤78.4 mL/min/1. 73m²) was estimated according to SUA quartiles (men, Q1 ≤ 5.0, Q2 5.1–5.9, Q3 6.0–6.6, and Q4 ≥ 6.7; women, Q1 ≤ 3.8, Q2 3.9–4.3, Q3 4.4–4.9, and Q4 ≥ 5.0 mg/dL) after adjustment for age, body mass index, systolic blood pressure, HbA1c, high and low density lipoprotein cholesterol, and smoking and drinking habits. The adjusted mean of each quartile was also calculated.

Results

Multivariable-adjusted means of eGFR showed a graded decrease in higher SUA quartiles (men, Q1 90.5, Q2 88.0, Q3 83.5, and Q4 82.0; women, Q1 95.7, Q2 91.3, Q3 89.2, and Q4 86.7). In addition, the multivariable-adjusted odds ratios for having a lower eGFR (95% confidence interval) for each SUA quartile compared with Q1 was Q2 2.29 (0.98, 5.35), Q3 4.94 (2.04, 11.97), and Q4 8.01 (3.20, 20.04) for men, and was Q2 2.20 (1.12, 4.32), Q3 2.68 (1.39, 5.20), and Q4 4.96 (2.62, 9.41) for women.

Conclusions

There was a graded inverse relationship between mild elevations in SUA levels and eGFR assessed by cystatin C in an apparently healthy Japanese population without CKD. This association was similar in both men and women.

Relationship between serum uric acid and clustering of cardiovascular disease risk factors and renal disorders among Shanghai population: a multicentre and cross-sectional study

OBJECTIVES

To estimate the current prevalence of cardiovascular disease risk factors (CRFs) and renal disorders across serum uric acid (SUA) quartiles, and evaluate the relationships between SUA and CRFs and renal diseases in Shanghai population.

STUDY DESIGN

Observational, cross-sectional study.

SETTING

Data were obtained from the physical check-up of local residents at three hospitals in Shanghai.

PARTICIPANTS

Residents were invited to take part in a physical check-up and provided informed consent. Exclusion criteria were diseases that resemble cancer, hepatic disease, and other coexisting illnesses including autoimmune kidney diseases and renal artery stenosis, individuals treated with xanthine oxidase inhibitors, and those with incomplete information. There are 26 768 individuals in our study.

PRIMARY AND SECONDARY OUTCOME MEASURES

Hyperuricaemia was defined as SUA ≥7 mg/dL in men and ≥6 mg/dL in women or taking xanthine oxidase inhibitors. Subjects were divided into gender-specific quartiles. We estimate the prevalence of CRFs and renal disorders across SUA quartiles. The relationships between SUA and CRFs and renal disorders in both genders were evaluated using logistic regression analysis.

RESULTS

There was a significant increase in the prevalence of major CRFs and renal diseases across SUA quartiles in a separate analysis among men and women (all p trend <0.001). After multiple adjustment, hyperuricaemia positively correlated with obesity (male OR=3.165, p<0.001; female OR=3.776, p<0.001), hypertension (male OR=1.341, p<0.001; female OR=1.289, p=0.006), dyslipidaemia (male OR=2.490, p<0.001; female OR=3.614, p<0.001), chronic kidney disease (male OR=7.081, p<0.001; female OR=11.571, p<0.001) and nephrolithiasis (male OR=1.469, p<0.001; female OR=1.242, p=0.041), but negatively correlated with diabetes mellitus (male OR=0.206, p<0.001; female OR=0.524, p<0.001). There was a stronger association between hyperuricaemia and clustered CRFs as well as chronic kidney disease in women than in men.

CONCLUSIONS

In Shanghai population, concomitant with the elevated level of SUA, the prevalence of CRFs and renal diseases was rising. Hyperuricaemia was significantly associated with CRFs and renal disorders, especially in women.

Association of serum uric acid levels with the incident of kidney disease and rapid eGFR decline in Chinese individuals with eGFR > 60 mL/min/1.73 m2 and negative proteinuria

BACKGROUND

Epidemiological studies suggest that higher serum uric acid (SUA) level is significantly associated with kidney disease development. However, it remains debatable whether higher SUA is independently associated with new-onset kidney disease and rapid eGFR decline in individuals with estimated glomerular filtration rate (eGFR) ≥ 60 mL/min/1.73 m² and negative proteinuria.

METHODS

This was a large, single-center, retrospective 6-year cohort study at People's Hospital of Tonglu County, Zhejiang, from 2001 to 2006. We enrolled 10,677 participants (19-92 years) with eGFR ≥ 60 mL/min/1.73 m² and without dipstick proteinuria at baseline. The association between SUA change and the occurrence of renal outcomes and annual eGFR decline were evaluated using Cox models with adjustment for confounders.

RESULTS

Higher quartiles (2.51%) of SUA levels were associated with greater prevalence of kidney disease compared with quartile 1 (0.52%), 2 (1.13%) and 3 (1.76%), respectively. In addition, greater baseline SUA levels [OR (95% CI) 3.29(1.68-6.45), p < 0.001] and increased SUA [1.36(1.23-1.50), p < 0.001] were all associated with greater odds of renal disease progression when comparing the 4th quartile of annual eGFR decline rate with the 1st quartile. In addition, both of higher baseline SUA levels and increased SUA change were the risk factors of rapid annual eGFR decline along with male gender, lower albumin, hematocrit and creatinine levels, higher hemoglobin levels and hyperlipidemia after multivariable adjustments when compared with each quartile group.

CONCLUSIONS

Increasing SUA were independent risk factor for the prevalent of kidney disease and rapid eGFR decline and reduced SUA over time could abate kidney disease development in a Chinese community.

Interactive effect of serum uric acid and total bilirubin for micro-vascular disease of type 2 diabetes in China

AIMS

Serum uric acid (SUA) and bilirubin at high levels had both pro-oxidant and anti-oxidant properties. The present study aimed to examine additive interactions between SUA and total bilirubin (TBIL) for the risk of micro-vascular disease (MVD) in type 2 diabetes mellitus (T2DM).

METHODS

A cross-sectional survey of 6713 inpatients with T2DM was conducted in 81 tertiary care hospitals in China. MVD was defined as having either prior diabetic retinopathy (DR) or diabetic nephropathy (DN). Binary logistic regression was used to estimate odds ratios of SUA and TBIL for MVD. Additive interaction was measured by three indices, i.e., relative excess risk due to interaction, attributable proportion due to interaction and synergy index.

RESULTS

Among 6713 inpatients, 408 (6.08%) suffered from MVD. SUA ≥ 283 μmol/l (i.e., its media) was defined as high SUA, and TBIL <11.5 μmol/l (n = 2290 or 34.11%) was defined as low TBIL. Overall, 621 patients were exposed to co-presence of high SUA and low TBIL. The co-presence of both factors greatly increased the effect sizes from 1.03(95%CI: 0.72-1.46) (high SUA alone) or 0.70(95%CI: 0.48-1.05) (low TBIL alone) to 1.90 (95%CI: 1.26-2.87) for MVD in multivariable analysis. The additive interaction of both factors was significant for MVD in both univariable analysis and multivariable analysis.

CONCLUSIONS

Co-presence of both high SUA and low TBIL indentified a group of patients at a markedly increased risk of MVD in high-risk Chinese patients with T2DM.

Spinal Gout Without Spinal Symptom in a Junior School Student: A Case Report

STUDY DESIGN

Case report.

OBJECTIVE

We report a case of a 16-year-old boy with intermittent and migratory polyarthralgia, who made a diagnostic dilemma.

SUMMARY OF BACKGROUND DATA

Spinal involvement without spinal symptom in gout seems to be rare. However, the relationship of spinal gout to symptoms is poorly understood.

METHODS

Description of the case report.

RESULTS

Laboratory findings cannot explain his symptoms; however, a computed tomography of the pelvis revealed the presence of space-occupying lesion involving the left side of spine at L5-S1 level, and the later biopsy revealed that was a urate crystal, which help us make the diagnosis of spinal gout.

CONCLUSION

Gout can be a cunning disease which has various manifestations, and spinal involvement can be asymptomatic.

LEVEL OF EVIDENCE

5.

Relation of uric acid level to rapid kidney function decline and development of kidney disease: The Jackson Heart Study

Whether elevated uric acid (UA) is an independent risk factor for chronic kidney disease (CKD) is not well established. The authors evaluated the relationship of UA with rapid kidney function decline (RKFD) and incident CKD among 3702 African Americans (AAs) in the Jackson Heart Study with serum UA levels measured at baseline exam (2000-2004). RKFD was defined as ≥ 30% eGFR loss and incident CKD as development of eGFR < 60 mL/min/1.73 m2 with a ≥ 25% decline in eGFR between baseline and exam 3 (2009-2013). RKFD and CKD were found in 11.4% and 7.5% of the participants, respectively. In a fully adjusted model, the odds of RKFD (OR, 1.8; 95% CI, 1.25-2.49) and incident CKD (OR, 2.00; 95% CI, 1.31-3.06) were significantly higher among participants in the top UA quartile vs bottom quartile. In the JHS, elevated UA was significantly associated with RKFD and incident CKD.

Augmented Association Between Blood Pressure and Proteinuria in Hyperuricemic Patients With Nonnephrotic Chronic Kidney Disease

BACKGROUND

Hyperuricemia (HU) may enhance susceptibility to hypertensive renal damage via disrupted autoregulation of glomerular hemodynamics. The effect of HU on the association between blood pressure (BP) and proteinuria remains unknown in patients with chronic kidney disease (CKD).

METHODS

In total, 109 patients with nonnephrotic CKD (55 men and 54 females) who underwent renal biopsy were recruited. Arteriolar hyalinosis was semiquantitatively assessed via arteriole grading. Correlation between BP and urine protein (UP) level was examined based on the presence of HU, which was defined as the use of urate-lowering drugs or serum uric acid levels of ≥7 and ≥5 mg/dl in males and females, respectively, which were associated with increased risks of hyalinosis in our previous study.

RESULTS

Median age, BP, estimated glomerular filtration rate, and UP level were 38 years, 124/74 mm Hg, 82 ml/min/1.73 m2, and 0.8 g/gCr, respectively. In patients with HU (n = 59), log-transformed systolic BP (SBP) was significantly correlated with log-transformed UP level (r = 0.49, P < 0.0001); this was not observed in patients without HU (n = 50). Multiple regression analysis (R2 = 0.21, P = 0.0001) revealed that the interaction between HU and log-transformed SBP with respect to proteinuria was significantly correlated with log-transformed UP level (β = 7.0, P = 0.03), independent of age, sex, and potential confounding factors; however, this statistical significance was completely eliminated after adjustment for the arteriolar hyalinosis index.

CONCLUSIONS

HU potentiates susceptibility to hypertensive glomerular damage via disrupted autoregulation in patients with nonnephrotic CKD.

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.

Uric acid-lowering and renoprotective effects of topiroxostat, a selective xanthine oxidoreductase inhibitor, in patients with diabetic nephropathy and hyperuricemia: a randomized, double-blind, placebo-controlled, parallel-group study (UPWARD study)

BACKGROUND

Hyperuricemia is supposed to be an independent risk factor for kidney dysfunction in diabetic patients. We attempted to examine the uric acid-lowering effect and the renoprotective effect of topiroxostat, a selective xanthine oxidoreductase inhibitor, in patients with diabetic nephropathy and hyperuricemia in this pilot study.

METHODS

The study design was randomized, double-blind, placebo-controlled, parallel-group study. A total of 65 patients with hyperuricemia and diabetic nephropathy with microalbuminuria were enrolled and assigned to either the topiroxostat group or the placebo group. Topiroxostat (stepwise dosing from 40 to 160 mg/day) or matching placebo was administered BID for 28 weeks. The primary endpoint was a change in the urinary albumin-to-creatinine ratio in the first-morning-void urine sample. Secondary endpoints were changes in the estimated glomerular filtration rate and the serum uric acid level.

RESULTS

At 28 weeks, there was no significant difference in the percent change from baseline in the urinary albumin-to-creatinine ratio between the two groups (topiroxostat: 0 vs. placebo: 17%, p = 0.3206), but the changes in the estimated glomerular filtration rate (- 0.2 vs. - 4.0 mL/min/1.73 m², p = 0.0303) and the serum uric acid level (- 2.94 vs. - 0.20 mg/dL, p < 0.0001) were significantly different between the topiroxostat and placebo groups. Gouty arthritis occurred in 1 patient in the placebo group and no patients in the topiroxostat group.

CONCLUSION

These findings support that diabetic nephropathy combined with hyperuricemia may be associated with kidney dysfunctions. Topiroxostat provides strict control of the serum uric acid level preventing decline of eGFR in these patients.

Albuminuria Increases the Risks for Both Alzheimer Disease and Vascular Dementia in Community-Dwelling Japanese Elderly: The Hisayama Study

Background

Epidemiologic evidence has emerged to reveal an association of albuminuria and low estimated glomerular filtration rate (eGFR) with dementia, but the findings are inconsistent. In addition, there are limited studies addressing the association between albuminuria and Alzheimer disease (AD).

Methods and Results

A total of 1562 community‐dwelling Japanese subjects aged ≥60 years without dementia were followed up for 10 years. The outcomes were incidence of all‐cause dementia and its subtypes, namely, AD and vascular dementia (VaD). The hazard ratios for the outcomes were estimated according to urine albumin–creatinine ratio (UACR) and eGFR levels using a Cox proportional hazards model. During the follow‐up, 358 subjects developed all‐cause dementia (238 AD and 93 VaD). Higher UACR level was significantly associated with greater multivariable‐adjusted risks of all‐cause dementia (hazard ratios [95% confidence intervals]: 1.00 [reference], 1.12 [0.78–1.60], 1.65 [1.18–2.30], and 1.56 [1.11–2.19] for UACR of ≤6.9, 7.0–12.7, 12.8–29.9, and ≥30.0 mg/g, respectively), AD (1.00 [reference], 1.20 [0.77–1.86], 1.75 [1.16–2.64], and 1.58 [1.03–2.41], respectively), and VaD (1.00 [reference], 1.03 [0.46–2.29], 1.94 [0.96–3.95], and 2.19 [1.09–4.38], respectively). On the other hand, lower eGFR level was marginally associated with greater risk of VaD, but not AD. Subjects with UACR ≥12.8 mg/g and eGFR of <60 mL/min per 1.73 m² had 3.3‐fold greater risk of VaD than those with UACR <12.8 mg/g and eGFR of ≥60 mL/min per 1.73 m².

Conclusions

Albuminuria is a significant risk factor for the development of both AD and VaD in community‐dwelling Japanese elderly. Moreover, albuminuria and low eGFR are mutually associated with a greater risk of VaD.

Efficacy and safety of tofogliflozin in Japanese patients with type 2 diabetes mellitus with inadequate glycaemic control on insulin therapy (J-STEP/INS): Results of a 16-week randomized, double-blind, placebo-controlled multicentre trial

AIMS

To assess the effects of 16 weeks of tofogliflozin (sodium-glucose co-transporter-2 [SGLT2] inhibitor) treatment vs placebo on glycated haemoglobin (HbA1c) levels in Japanese patients with type 2 diabetes mellitus (T2DM) inadequately controlled with insulin monotherapy or insulin plus a dipeptidyl peptidase-4 (DPP-4) inhibitor.

METHODS

The study comprised a 16-week, multicentre, double-blind, placebo-controlled period and a 36-week extension (NCT02201004). Men and women (aged ≥20 and ≤75 years) with T2DM (HbA1c ≥7.5% and ≤10.5%) were randomized 2:1 to tofogliflozin 20 mg once/day or placebo. The primary endpoint was change in HbA1c from baseline. Insulin reduction was not permitted during this study.

RESULTS

A total of 211 patients were randomized (141 tofogliflozin, 70 placebo). Addition of tofogliflozin to insulin therapy was significantly superior to placebo for lowering HbA1c (-0.59 vs +0.48%; P < .0001), fasting plasma glucose (-27.2 vs +5.3 mg/dL; P < .0001), postprandial plasma glucose (-65.0 vs +3.2 mg/dL; P < 0.0001), serum uric acid (-0.18 vs +0.07 mg/dL; P = .0062), body weight (-1.34 vs +0.03 kg; P < .0001) and daily insulin dose (-1.3 vs -0.2 U, P = .0152). Hypoglycaemia occurred in 30.7% of patients receiving tofogliflozin vs 21.4% for placebo. Two patients treated with tofogliflozin each had a genital or urinary tract infection.

CONCLUSIONS

This 16-week double-blind study indicated that, in patients with T2DM whose HbA1c levels were poorly controlled with insulin monotherapy or insulin plus a DPP-4 inhibitor, addition of tofogliflozin was an effective treatment option with an acceptable safety profile.

Uric acid in the pathogenesis of metabolic, renal, and cardiovascular diseases: A review

The association between uric acid (UA) on one side and systemic hypertension (Htn), dyslipidemia, glucose intolerance, overweight, fatty liver, renal disease and cardiovascular disease (CVD) on the other side is well recognized. However, the causal relationship between UA and these different clinical problems is still debatable. The recent years have witnessed hundreds of experimental and clinical trials that favored the opinion that UA is a probable player in the pathogenesis of these disease entities. These studies disclosed the strong association between hyperuricemia and metabolic syndrome (MS), obesity, Htn, type 2 diabetes mellitus (DM), non-alcoholic fatty liver disease, hypertriglyceridemia, acute kidney injury, chronic kidney disease (CKD), coronary heart disease (CHD), heart failure and increased mortality among cardiac and CKD patients. The association between UA and nephrolithiasis or preeclampsia is a non-debatable association. Recent experimental trials have disclosed different changes in enzyme activities induced by UA. Nitric oxide (NO) synthase, adenosine monophosphate kinase (AMPK), adenosine monophosphate dehydrogenase (AMPD), and nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase are affected by UA. These changes in enzymatic activities can lead to the observed biochemical and pathological changes associated with UA. The recent experimental, clinical, interventional, and epidemiologic trials favor the concept of a causative role of UA in the pathogenesis of MS, renal, and CVDs.

Elevated Serum Uric Acid Level Predicts Rapid Decline in Kidney Function

BACKGROUND

While elevated serum uric acid level (SUA) is a recognized risk factor for chronic kidney disease, it remains unclear whether change in SUA is independently associated with change in estimated glomerular filtration rate (eGFR) over time. Accordingly, we examined the longitudinal associations between change in SUA and change in eGFR over 5 years in a general Japanese population.

METHODS

This was a large, single-center, retrospective 5-year cohort study at St. Luke's International Hospital, Tokyo, Japan, between 2004 and 2009. We included 13,070 subjects (30-85 years) in our analyses whose data were available between 2004 and 2009. Of those, we excluded 492 subjects with eGFR <60 mL/min/1.73 m2 at baseline. In addition to examining the entire cohort (n = 12,578), we stratified our analyses by baseline eGFR groups: 60-90, 90-120, and ≥120 mL/min/1.73 m2. Linear and logistic regressions models were applied to examine the relationships between baseline and change in SUA, change in eGFR, and rapid eGFR decline (defined as the highest quartile of change in eGFR), adjusted for age, gender, body mass index, abdominal circumference, hypertension, dyslipidemia, and diabetes mellitus.

RESULTS

After multivariable adjustments including baseline eGFR, 1 mg/dL increase in baseline SUA was associated with greater odds of developing rapid eGFR decline (OR 1.27, 95% CI 1.17-1.38), and 1 mg/dL increase in SUA over 5 years was associated with 3.77-fold greater odds of rapid eGFR decline (OR 3.77, 95% CI 3.35-4.26).

CONCLUSIONS

Elevated baseline SUA and increasing SUA over time were independent risk factors for rapid eGFR decline over 5 years.

Clinical Effects of Topiroxostat on Renal and Endothelial Function in A Patient with Chronic Kidney Disease and Hyperuricemic Arteriolopathy: A Case Report

Hyperuricemia is associated with the progression of chronic kidney disease (CKD) and cardiovascular diseases. Topiroxostat, a selective xanthine oxidase inhibitor, effectively reduces serum uric acid (UA) levels and urinary albumin excretion (UAE) in CKD patients. A 50-year-old Japanese man was referred to our hospital due to albuminuria and hyperuricemia, and renal biopsy showed a typical hyperuricemic arteriolopathy. Treatment with topiroxostat decreased serum UA levels (9.2 mg/dL at baseline to 6.4 mg/dL after 6 months), UAE (388 to 88 mg/g.cr), and urinary level of liver-type fatty acid-binding protein (28.8 to 19.8 µg/g.cr). Interestingly, topiroxostat treatment was associated with a trend towards improved flow-mediated dilation (5.4 to 5.8%). These results suggested that topiroxostat in CKD patients with hyperuricemia is potentially effective, not only for ameliorating renal damages but also for improving endothelial function beyond its UA-lowering action.