Role of elevated serum uric acid levels at the onset of overt nephropathy in the risk for renal function decline in patients with type 2 diabetes

Deterioration in ankle reflex is associated with a reduced estimated glomerular filtration rate in patients with type 2 diabetes: A retrospective observational cohort study

AIMS/INTRODUCTION

We investigated the association between the ankle reflex and the estimated glomerular filtration rate (eGFR) in patients with type 2 diabetes.

MATERIALS AND METHODS

This was a single-center, retrospective, observational cohort study. A total of 1,387 patients who underwent an ankle reflex examination between January 2005 and December 2015 were included in the analysis for the primary outcome. The findings of the ankle reflex examination were classified into three groups: normal, decreased, or absent. The primary outcome was defined as the incidence of a 40% loss of eGFR from baseline. A survival time analysis using the Kaplan-Meier method and a regression analysis using a Cox proportional hazards model were conducted to evaluate the association between the ankle reflex test results and loss of eGFR.

RESULTS

The ankle reflex test results were as follows: normal, n = 678 (48.9%); decreased, n = 270 (19.5%); and absent, n = 439 (31.6%) patients. The median follow-up period was 5.6 years in the observational period. In the univariate regression analysis, decreased and absent ankle reflexes were significantly associated with loss of eGFR. Moreover, decreased ankle reflex (hazard ratio: 1.83, 95% confidence interval: 1.16-2.87) and absent ankle reflex (hazard ratio: 2.57, 95% confidence interval: 1.76-3.76) were independently associated with loss of eGFR after adjusting for prognostic risk factors.

CONCLUSIONS

Decreased and absent ankle reflexes are closely and independently associated with loss of eGFR in patients with type 2 diabetes.

Relationship between hyperuricemia and the risk of cardiovascular events and chronic kidney disease in both the general population and hypertensive patients: A systematic review and meta-analysis

BACKGROUND

To explore the relationships between hyperuricemia and the risk of cardiovascular diseases (CVD) and chronic kidney disease (CKD) in both the general population and hypertensive patients through meta-analysis.

METHODS AND RESULTS

We systematically searched PubMed, Embase, and Cochrane Library databases from January 2012. The eligibility criteria were predefined, and quality was assessed using the Newcastle-Ottawa Scale (NOS). Stata 15.1 was used for meta-analysis, heterogeneity and sensitivity analysis. Subgroup analysis was used to explore heterogeneity, funnel plots and Egger tests were used to assesse publication bias and applicability. A total of 10,662 studies were retrieved, 45 of which were included in this meta-analysis utilizing a random effects model. Hyperuricemia was significantly associated with an increased risk of new-onset hypertension (RR = 1.36, 95% CI 1.16-1.59; I2 = 98.8%), total CVD (RR = 1.53, 95% CI 1.23-1.89; I2 = 93.7%), stroke (RR = 1.97, 95% CI 1.71-2.26, I2 = 0.0%), coronary heart disease (CHD) (RR = 1.56, 95% CI 1.06-2.30, I2 = 93.3%), and CKD (RR = 1.71, 95% CI 1.56-1.87; I2 = 87.3%). However, subgroup analysis showed no significant associations between hyperuricemia and hypertension in non-Asian populations (RR = 0.88, 95% CI 0.59-1.33), or between hyperuricemia and CVD with a follow-up duration <5 years (RR = 1.26, 95% CI 0.97-1.63). Among hypertensive patients, hyperuricemia was significantly associated with total CVD (RR = 2.32, 95% CI 1.31-4.12, I2 = 90.2%), but not with stroke (RR = 1.48, 95% CI 0.86-2.55; I2 = 90.7%) or CHD (RR = 1.51, 95% CI 0.98-2.33; I2 = 71.7%).

CONCLUSION

Hyperuricemia was significantly associated with an increased risk of new-onset hypertension, total CVD, stroke, CHD, and CKD in the general population. Among hypertensive patients, hyperuricemia was associated with an increased risk of CVD but not stroke or CHD alone.

REGISTRATION NUMBER

CRD42022370692.

Hyperuricemia predicts increased cardiovascular events in patients with chronic coronary syndrome after percutaneous coronary intervention: A nationwide cohort study from Japan

Background

The causal relationship between hyperuricemia and cardiovascular diseases is still unknown. We hypothesized that hyperuricemic patients after percutaneous coronary intervention (PCI) had a higher risk of major adverse cardiovascular events (MACE).

Methods

This was a large-scale multicenter cohort study. We enrolled patients with chronic coronary syndrome (CCS) after PCI between April 2013 and March 2019 using the database from the Clinical Deep Data Accumulation System (CLIDAS), and compared the incidence of MACE, defined as a composite of cardiovascular death, myocardial infarction, and hospitalization for heart failure, between hyperuricemia and non-hyperuricemia groups.

Results

In total, 9,936 patients underwent PCI during the study period. Of these, 5,138 patients with CCS after PCI were divided into two group (1,724 and 3,414 in the hyperuricemia and non-hyperuricemia groups, respectively). The hyperuricemia group had a higher prevalence of hypertension, atrial fibrillation, history of previous hospitalization for heart failure, and baseline creatinine, and a lower prevalence of diabetes than the non-hyperuricemia group, but the proportion of men and age were similar between the two groups. The incidence of MACE in the hyperuricemia group was significantly higher than that in the non-hyperuricemia group (13.1 vs. 6.4%, log-rank P < 0.001). Multivariable Cox regression analyses revealed that hyperuricemia was significantly associated with increased MACE [hazard ratio (HR), 1.52; 95% confidential interval (CI), 1.23-1.86] after multiple adjustments for age, sex, body mass index, estimated glomerular filtration rate, left main disease or three-vessel disease, hypertension, diabetes mellitus, dyslipidemia, history of myocardial infarction, and history of hospitalization for heart failure. Moreover, hyperuricemia was independently associated with increased hospitalization for heart failure (HR, 2.19; 95% CI, 1.69-2.83), but not cardiovascular death or myocardial infarction after multiple adjustments. Sensitive analyses by sex and diuretic use, B-type natriuretic peptide level, and left ventricular ejection fraction showed similar results.

Conclusion

CLIDAS revealed that hyperuricemia was associated with increased MACE in patients with CCS after PCI. Further clinical trials are needed whether treating hyperuricemia could reduce cardiovascular events or not.

Decline in renal function associated with cardiovascular autonomic neuropathy positively coordinated with proteinuria in patients with type 2 diabetes

AIMS/INTRODUCTION

To investigate the association between cardiovascular autonomic neuropathy (CAN) assessed by the coefficient of variation of the R-R interval and the reduction in the estimated glomerular filtration rate (eGFR) in patients with type 2 diabetes.

MATERIALS AND METHODS

This retrospective observational cohort study enrolled type 2 diabetes patients who had their coefficient of variation of the R-R interval measured on an electrocardiogram from January 2005 to December 2018. CAN was defined using the reference coefficient of variation of the R-R interval value based on age and sex. The primary outcome was set as a 40% eGFR decline from baseline. Regression analyses using the Cox proportional hazards model were carried out to evaluate the association.

RESULTS

Of the 831 patients, 118 (14.2%) were diagnosed with CAN. In the analysis of the primary outcome, the median follow-up period was 5.3 years, and 25 (21.2%) patients with CAN and 78 (10.9%) patients without CAN developed a 40% eGFR decline. In the univariate regression analysis, CAN was significantly associated with a 40% eGFR decline (hazard ratio 2.42, 95% confidence interval 1.54-3.80). In the multivariate analysis, CAN remained almost significant after adjusting for the prognostic risk factors for CAN and the decline in the renal function, and an interaction with proteinuria was found. In analyses for the interaction effect between CAN and proteinuria, the presence of CAN synergistically increased the risk of an eGFR decline in patients with macroproteinuria.

CONCLUSIONS

CAN strongly increased the risk of a 40% eGFR decline from baseline, especially in type 2 diabetes patients with macroproteinuria.

Novel biomarkers and therapeutic approaches for diabetic retinopathy and nephropathy: Recent progress and future perspectives

The global burden due to microvascular complications in patients with diabetes mellitus persists and even increases alarmingly, the intervention and management are now encountering many difficulties and challenges. This paper reviews the recent advancement and progress in novel biomarkers, artificial intelligence technology, therapeutic agents and approaches of diabetic retinopathy and nephropathy, providing more insights into the management of microvascular complications.

Estimation of the prevalence of type 2 diabetes in combination with diabetic kidney disease and identification of the associated factors in patients attending primary hospitals in Anhui Province, China

Objective

To evaluate the prevalence of type 2 diabetes mellitus (T2DM) with chronic kidney disease (DM-CKD) and identify the associated factors in patients attending primary hospitals in Anhui Province, China.

Methods

A multi-stage sampling method was used to collect the demographic information, general clinical data, and details of the kidney disease of patients in 2019 through a questionnaire survey, physical examination, and laboratory examination.

Results

A total of 1067 patients with T2DM were studied, of whom 345 had chronic kidney disease (CKD; 32.33%); 18.8%, 12.2%, 58.0%, 9.9% and 1.2% of the participants had stages 1 to 5 CKD. Fifty-point-three percent of the participants were female and they were 59 ± 11.3 years old. Multivariate regression analysis revealed that age, systolic blood pressure, the duration of diabetes, hyperlipidaemia, and smoking were associated with DM-CKD. The duration of diabetes was positively associated with body mass index, 2-hour postprandial glucose, fasting blood glucose concentration, glycosylated haemoglobin, total cholesterol concentration and triglyceride concentration.

Conclusions

The incidence of DM-CKD is relatively high in primary hospitals in Anhui Province. Appropriate preventive and therapeutic measures should be instituted according to the age, the duration of diabetes, sex, hypertension, smoking habits, and lipidaemia of patients.

Association between serum uric acid and renal outcome in patients with biopsy-confirmed diabetic nephropathy

OBJECTIVE

To investigate the relationship between serum uric acid (SUA) level and renal outcome in patients with type 2 diabetes mellitus (T2DM) and diabetic nephropathy (DN).

METHODS

A total of 393 Chinese patients with T2DM and biopsy-proven DN and followed at least 1 year were enrolled in this study. Patients were stratified by the quartiles of baseline level of SUA: Q1 group: 286.02 ± 46.66 μmol/L (n = 98); Q2 group: 358.23 ± 14.03 μmol/L (n = 99); Q3 group: 405.50 ± 14.59 μmol/L (n = 98) and Q4 group: 499.14 ± 56.97μmol/L (n = 98). Renal outcome was defined by progression to end-stage renal disease (ESRD). Kaplan-Meier survival analysis and Cox proportional hazards model were used to analyze the association between SUA quartiles and the renal outcomes.

RESULTS

During the median 3-year follow-up period, there were 173 ESRD outcome events (44.02%). No significant difference between SUA level and the risk of progression of DN (P = 0.747) was shown in the Kaplan-Meier survival analysis. In multivariable-adjusted model, hazard ratios for developing ESRD were 1.364 (0.621-2.992; P = 0.439), 1.518 (0.768-3.002; P = 0.230) and 1.411 (0.706-2.821; P = 0.330) for the Q2, Q3 and Q4, respectively, in comparison with the Q1 (P = 0.652).

CONCLUSIONS

No significant association between SUA level and renal outcome of ESRD in Chinese patients with T2DM and DN was found in our study. Besides, the role of uric acid-lowering therapy in delaying DN progression and improving ESRD outcome had not yet been proven. Further study was needed to clarify the renal benefit of the uric acid-lowering therapy in the treatment of DN.

Serum Uric Acid Levels and Risk of Rapid Decline of Estimated Glomerular Filtration Rate in Patients with Type 2 Diabetes: Findings from a 5-Year Prospective Cohort Study

This study investigated the association between serum uric acid (SUA) levels with rapid decline of the estimated glomerular filtration rate (eGFR) in type 2 diabetes (T2 DM) patients. A prospective cohort study was conducted in a community-based hospital in Vietnam. We followed 405 T2DM patients with normal kidney function for five years. Rapid progression of kidney function was defined as an average annual decrease of eGFR of at least 4 mL/min/1.73 m² and was found in 16.0% of patients. Patients in the SUA high tertile ( ≥6 mg/dL) had higher BMI (p = 0.004), lower HbA1c (p = 0.001), lower eGFR (p < 0.001) and higher rate of hypertension than low and middle tertile. After adjusting for age and sex, rapid progression of renal function was significantly associated with SUA level (OR = 1.22, 95% CI 1.02-1.45, p = 0.026). This association was marginally significant when more covariates were included in the model (OR = 1.20, 95% CI 0.99-1.46, p = 0.065). However, the association between tertiles of SUA and rapid decline of eGFR was not statistically significant. This study demonstrates neither a strong significant association between SUA and rapid decline of eGFR nor evidence to refuse the role of SUA levels in the increased risk of renal function decline in in T2DM patients.

Development of Biomarkers and Molecular Therapy Based on Inflammatory Genes in Diabetic Nephropathy

Diabetic Nephropathy (DN) is a debilitating consequence of both Type 1 and Type 2 diabetes affecting the kidney and renal tubules leading to End Stage Renal Disease (ESRD). As diabetes is a world epidemic and almost half of diabetic patients develop DN in their lifetime, a large group of people is affected. Due to the complex nature of the disease, current diagnosis and treatment are not adequate to halt disease progression or provide an effective cure. DN is now considered a manifestation of inflammation where inflammatory molecules regulate most of the renal physiology. Recent advances in genetics and genomic technology have identified numerous susceptibility genes that are associated with DN, many of which have inflammatory functions. Based on their role in DN, we will discuss the current aspects of developing biomarkers and molecular therapy for advancing precision medicine.

Impact of Plasma Xanthine Oxidoreductase Activity on the Mechanisms of Distal Symmetric Polyneuropathy Development in Patients with Type 2 Diabetes

To unravel associations between plasma xanthine oxidoreductase (XOR) and diabetic vascular complications, especially distal symmetric polyneuropathy (DSP), we investigated plasma XOR activities using a novel assay. Patients with type 2 diabetes mellitus (T2DM) with available nerve conduction study (NCS) data were analyzed. None were currently taking XOR inhibitors. XOR activity of fasting blood samples was assayed using a stable isotope-labeled substrate and LC-TQMS. JMP Clinical version 5.0. was used for analysis. We analyzed 54 patients. Mean age was 64.7 years, mean body mass index was 26.0 kg/m², and mean glycated hemoglobin was 9.4%. The logarithmically transformed plasma XOR activity (ln-XOR) correlated positively with hypoxanthine, xanthine, visceral fatty area, and liver dysfunction but negatively with HDL cholesterol. ln-XOR correlated negatively with diabetes duration and maximum intima-media thickness. Stepwise multiple regression analysis revealed ln-XOR to be among selected explanatory factors for various NCS parameters. Receiver operating characteristic curves showed the discriminatory power of ln-XOR. Principal component analysis revealed a negative relationship of ln-XOR with F-waves as well as positive relationships of ln-XOR with hepatic steatosis and obesity-related disorders. Taken together, our results show plasma XOR activity to be among potential disease status predictors in T2DM patients. Plasma XOR activity measurements might reliably detect pre-symptomatic DSP.

Clinical features of and risk factors for normoalbuminuric diabetic kidney disease in hospitalized patients with type 2 diabetes mellitus: a retrospective cross-sectional study

BACKGROUND

Normoalbuminuric diabetic kidney disease (NADKD) is a newly defined DKD, the clinical features and pathogenesis for which are still being understood. This study aimed to investigate the features and risk factors for NADKD in patients with type 2 diabetes mellitus (T2DM).

METHODS

A retrospective cross-sectional study was conducted. The related clinical and laboratory data of patients with T2DM hospitalized between August 2012 and January 2020 were collected for statistical analysis. We classified the patients with T2DM into four groups on the basis of the presence or absence of albuminuria and reduced estimated glomerular filtration rate (eGFR). Analysis of variance, the Kruskal-Wallis test, and the chi-square test were used to compare the groups. Binary logistic regression analyses with a forward stepwise method were performed to explore the risk factors for renal dysfunction in hospitalized patients with normoalbuminuric T2DM.

RESULTS

Among the 1620 patients evaluated, 500 (30.9%) had DKD, of which 9% had NADKD. The prevalence of stroke, cardiovascular events, carotid plaque, and peripheral arterial disease in NADKD was significantly higher than in a non-DKD control group (normoalbuminuric T2DM patients with eGFR of ≥60 ml/min/1.73 m²). Regression analyses revealed that three significant independent factors were associated with NADKD: age (OR = 1.089, confidence interval [CI] 95% [1.055-1.123], p < 0.001), previous use of renin-angiotensin system inhibitors (RASIs; OR = 2.330, CI 95% [1.212-4.481], p = 0.011), and glycated hemoglobin (HbA1c; OR = 0.839, CI 95% [0.716-0.983], p = 0.03).

CONCLUSIONS

NADKD is mainly associated with macrovascular rather than microvascular complications. NADKD is more common in patients with normoalbuminuric T2DM with older age, previous use of RASIs, and good glycemic control.

Associations of serum uric acid level with diabetic retinopathy and albuminuria in patients with type 2 diabetes mellitus

Objectives

To analyze the associations of serum uric acid (SUA) level with diabetic microvascular complications, including diabetic retinopathy (DR) and diabetic nephropathy (DN), in patients with type 2 diabetes mellitus (DM).

Methods

Three hundred eighty-nine inpatients with type 2 DM were included in this retrospective analysis. Nonmydriatic fundus cameras were used to identify DR. Urinary albumin creatinine ratio was used to identify DN. Patients were divided into four groups according to SUA quartiles.

Results

The prevalences of DR and albuminuria increased with increasing SUA level. Multivariate logistic regression analysis showed that, following adjustment for other risk factors, higher levels of SUA (Q3 and Q4) were associated with greater risk for DR, compared with the lower level (Q1) (odds ratio [OR]: 3.056, 95% confidence interval [CI]: 1.506–6.198; OR: 3.417, 95% CI: 1.635–7.139, respectively). Moreover, higher levels of SUA (Q2, Q3, and Q4) were associated with greater risk for albuminuria (OR: 2.418, 95% CI: 1.059–5.522; OR: 7.233, 95% CI: 3.145–16.635; and OR: 8.911, 95% CI: 3.755–21.147, respectively).

Conclusions

SUA level was independently associated with DR and albuminuria in patients with type 2 DM. Elevated SUA level might be predictive for the occurrence of DR and DN.

Associations of serum uric acid and urinary albumin with the severity of diabetic retinopathy in individuals with type 2 diabetes

Background

Diabetic retinopathy (DR) is a serious microvascular complication of type 2 diabetes mellitus (T2DM). The aim of this retrospective study was to reveal the risk factors for the severity of DR in individuals with T2DM. Demographic data and biochemical parameters were collected and analyzed.

Methods

A total of 518 individuals with type 2 diabetes were included. These individuals were classified into three groups according to the severity of diabetic retinopathy: non-diabetic retinopathy (NDR) group (N = 172), non proliferative diabetic retinopathy (NPDR) group (N = 184), and proliferative diabetic retinopathy (PDR) group (N = 162). Demographic and clinical measurement data of the individuals were collected by reviewing medical records and direct interview. The demographic data and biochemical parameters between groups were compared using Student’s t-test. Moreover, the factors related to severity of diabetic retinopathy were identified by using the multivariate logistic regression analysis.

Results

No significant difference in age, gender, body mass index (BMI), and diabetes duration was found among these three groups. The serum uric acid (SUA), total cholesterol (TC), low density lipoprotein cholesterol (LDL-c), homocysteine, and urinary albumin levels were significantly higher in the NPDR and PDR group than those in the NDR group (P < 0.05). The individuals in the PDR group had obviously higher levels of SUA, homocysteine, and urinary albumin than individuals in the NPDR group (P < 0.05). The multivariate logistic regression analysis revealed that high SUA, homocysteine, TC, LDL-c, and urinary albumin levels were associated with more serious diabetic retinopathy (OR > 1; P < 0.05).

Conclusion

The concentrations of SUA and urinary albumin are associated with the severity of DR in individuals with T2DM.

Xanthine Oxidase Inhibitor Febuxostat Exerts an Anti-Inflammatory Action and Protects against Diabetic Nephropathy Development in KK-Ay Obese Diabetic Mice

Hyperuricemia has been recognized as a risk factor for insulin resistance as well as one of the factors leading to diabetic kidney disease (DKD). Since DKD is the most common cause of end-stage renal disease, we investigated whether febuxostat, a xanthine oxidase (XO) inhibitor, exerts a protective effect against the development of DKD. We used KK-Ay mice, an established obese diabetic rodent model. Eight-week-old KK-Ay mice were provided drinking water with or without febuxostat (15 μg/mL) for 12 weeks and then subjected to experimentation. Urine albumin secretion and degrees of glomerular injury judged by microscopic observations were markedly higher in KK-Ay than in control lean mice. These elevations were significantly normalized by febuxostat treatment. On the other hand, body weights and high serum glucose concentrations and glycated albumin levels of KK-Ay mice were not affected by febuxostat treatment, despite glucose tolerance and insulin tolerance tests having revealed febuxostat significantly improved insulin sensitivity and glucose tolerance. Interestingly, the IL-1β, IL-6, MCP-1, and ICAM-1 mRNA levels, which were increased in KK-Ay mouse kidneys as compared with normal controls, were suppressed by febuxostat administration. These data indicate a protective effect of XO inhibitors against the development of DKD, and the underlying mechanism likely involves inflammation suppression which is independent of hyperglycemia amelioration.

[Correlation between fasting C-peptide and serum uric acid in patients with type 2 diabetes mellitus]

OBJECTIVE

To explore the relationship between fasting C-peptide (F-CP) and serum uric acid (SUA) in patients with type 2 diabetes mellitus (T2DM).

METHODS

A total of 347 hospitalized patients with T2DM were stratified according to F-CP level to analyze the impact of increased F-CP levels on SUA level and the incidence of hyperuricemia (HUA). The patients with an elevated SUA level (>420 µmol/L) and a normal SUA level (≤420 µmol/L) were compared for general data, fasting C-peptide and other clinical indexes. Pearson or Spearman correlation analysis was used to analyze the correlation of SUA level with F-CP levels and other parameters. The risk factors of elevated SUA were analyzed by binary logistic regression, multiple regression analysis and hierarchical interaction analysis. The ROC curve was used to analyze the independent risk factors of elevated SUA and determine the corresponding cut-off values.

RESULTS

Compared with those with a normal SUA level, patients with elevated SUA had higher body mass index (BMI), waist-to-hip ratio, F-CP, postprandial 2hC peptide (2hP-CP), triglyceride (TG), homocysteine (HCY), serum creatinine (SCr) level (P<0.05), and a greater percentage of drinking (44.8% vs 32.6%, P=0.006), but had significantly lowered levels of HbA1c, high-density lipoprotein (HDL), and estimated glomerular filtration rate (eGFR) (P<0.05). SUA was found to be positively correlated with F-CP, 2hP-CP, BMI, waist-to-hip ratio, diastolic blood pressure, TG, HCY, SCr, smoking and drinking (P<0.05), and was negatively correlated with gender, age, age of disease onset, HbA1c, HDL and eGFR (P<0.05). SUA level and the incidence of hyperuricemia increasea significantly with F-CP level (P<0.05). F-CP was identified as an independent risk factor for elevated SUA, and gender did not affect the relationship between F-CP and SUA. ROC curve analysis showed that a F-CP level >1.260 ng/mL was associated with a significantly increased risk of hyperuricemia in T2DM patients.

CONCLUSION

F-CP is closely related with SUA and may be an independent risk factor of elevated SUA in patients with T2DM.

[Correlation between fasting C-peptide and serum uric acid in patients with type 2 diabetes mellitus]

OBJECTIVE

To explore the relationship between fasting C-peptide (F-CP) and serum uric acid (SUA) in patients with type 2 diabetes mellitus (T2DM).

METHODS

A total of 347 hospitalized patients with T2DM were stratified according to F-CP level to analyze the impact of increased F-CP levels on SUA level and the incidence of hyperuricemia (HUA). The patients with an elevated SUA level (>420 µmol/L) and a normal SUA level (≤420 µmol/L) were compared for general data, fasting C-peptide and other clinical indexes. Pearson or Spearman correlation analysis was used to analyze the correlation of SUA level with F-CP levels and other parameters. The risk factors of elevated SUA were analyzed by binary logistic regression, multiple regression analysis and hierarchical interaction analysis. The ROC curve was used to analyze the independent risk factors of elevated SUA and determine the corresponding cut-off values.

RESULTS

Compared with those with a normal SUA level, patients with elevated SUA had higher body mass index (BMI), waist-to-hip ratio, F-CP, postprandial 2hC peptide (2hP-CP), triglyceride (TG), homocysteine (HCY), serum creatinine (SCr) level (P<0.05), and a greater percentage of drinking (44.8% vs 32.6%, P=0.006), but had significantly lowered levels of HbA1c, high-density lipoprotein (HDL), and estimated glomerular filtration rate (eGFR) (P<0.05). SUA was found to be positively correlated with F-CP, 2hP-CP, BMI, waist-to-hip ratio, diastolic blood pressure, TG, HCY, SCr, smoking and drinking (P<0.05), and was negatively correlated with gender, age, age of disease onset, HbA1c, HDL and eGFR (P<0.05). SUA level and the incidence of hyperuricemia increasea significantly with F-CP level (P<0.05). F-CP was identified as an independent risk factor for elevated SUA, and gender did not affect the relationship between F-CP and SUA. ROC curve analysis showed that a F-CP level >1.260 ng/mL was associated with a significantly increased risk of hyperuricemia in T2DM patients.

CONCLUSION

F-CP is closely related with SUA and may be an independent risk factor of elevated SUA in patients with T2DM.

Does Altered Uric Acid Metabolism Contribute to Diabetic Kidney Disease Pathophysiology?

PURPOSE OF REVIEW

Multiple experimental and clinical studies have identified pathways by which uric acid may facilitate the development and progression of chronic kidney disease (CKD) in people with diabetes. However, it remains uncertain if the association of uric acid with CKD represents a pathogenic effect or merely reflects renal impairment.

RECENT FINDINGS

In contrast to many published reports, a recent Mendelian randomization study did not identify a causal link between uric acid and CKD in people with type 1 diabetes. Two recent multicenter randomized control trials, Preventing Early Renal Function Loss in Diabetes (PERL) and FEbuxostat versus placebo rAndomized controlled Trial regarding reduced renal function in patients with Hyperuricemia complicated by chRonic kidney disease stage 3 (FEATHER), were recently designed to assess if uric acid lowering slows progression of CKD. We review the evidence supporting a role for uric acid in the pathogenesis of CKD in people with diabetes and the putative benefits of uric acid lowering.

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.

Gastrointestinal symptom prevalence depends on disease duration and gastrointestinal region in type 2 diabetes mellitus

AIM

To unravel relationships between gastrointestinal (GI) symptoms impairing quality of life (QOL) and clinical profiles of diabetes mellitus (DM) patients.

METHODS

We enrolled 134 outpatients with type 2 DM. Mean age was 64.7 years, mean body mass index was 24.7 kg/m², mean glycated hemoglobin was 7.1%, and mean DM duration was 13.7 years. GI symptom-related QOL was determined using the Izumo scale, based on five factors, i.e., heartburn, gastralgia, postprandial fullness, constipation and diarrhea. The sum of scores obtained for the three questions in each domain was calculated, and subjects with a score of 5 or higher were considered to be symptomatic with impaired QOL. JMP Clinical version 5.0 was used for all statistical analyses.

RESULTS

Lower abdominal symptoms were found to be more frequent than those affecting the upper abdomen. Diabetic duration and medications showed associations with GI symptoms. We identified differences in peak prevalences of the five symptoms. Gastralgia (P = 0.02 vs 10-14 years) and total GI symptoms (P = 0.01 and P = 0.02 vs 5-9 years and 10-14 years, respectively) peaked at a diabetes duration of 15-19 years. Heartburn (P = 0.004) and postprandial fullness (P = 0.03) tended to increase with disease duration. Constipation and diarrhea showed bimodal peaks, with the first early and the second late (e.g., P = 0.03 at 15-19 years vs 10-14 years for diarrhea) in the disease course. Finally, GI symptoms showed clustering that reflected the region of the GI tract affected, i.e., constipation and diarrhea had similar frequencies (P < 0.0001).

CONCLUSION

Our study highlights the importance of questioning patients about QOL impairment due to abdominal symptoms, especially in the early and the late periods of diabetes.

Changes of serum Mir-217 and the correlation with the severity in type 2 diabetes patients with different stages of diabetic kidney disease

The aim of this study is to investigate the correlation between serum microRNA-217 and the severity of diabetic kidney disease determined by albuminuria. Four hundred ninety five type 2 diabetes patients were divided into three groups: normoalbuminuric group, microalbuminuric group, and macroalbuminuric group. Serum microRNA-217 levels were validated by real-time polymerase chain reaction. Serum silent information regulator 1, Hypoxia-inducible factor-1α and vascular endothelial growth factor were determined by enzyme-linked immunosorbent assay. Compared with control, serum microRNA-217 levels were significantly increased in type 2 diabetes patients and gradually increased in patients of normoalbuminuric, microalbuminuric, and macroalbuminuric groups (P < 0.01). Moreover, increased levels of serum microRNA-217, hypoxia-inducible factor-1α, vascular endothelial growth factor, diabetes mellitus duration, fasting blood glucose, fasting insulin, homeostasis model assessment for insulin resistance, glycated hemoglobin, low-density lipoprotein, total cholesterol, triglyceride, uric acid, serum creatinine, blood urea nitrogen, and decreased levels of serum silent information regulator 1 and high-density lipoprotein were significantly correlated with Ln(ACR) (P < 0.05). In addition, serum microRNA-217 was positively correlated with diabetes mellitus duration, homeostasis model assessment for insulin resistance, glycated hemoglobin, Ln(ACR), low-density lipoprotein, total cholesterol, triglyceride, uric acid, serum creatinine, blood urea nitrogen, hypoxia-inducible factor-1α, vascular endothelial growth factor (P < 0.05), and negatively correlated with serum silent information regulator 1 (P = 0.002). Our findings suggest that microRNA-217 may have an association with the development of proteinuria in type 2 diabetes patients. Serum microRNA-217 may be involved in the development of diabetic kidney disease by promoting chronic inflammation, renal fibrosis, and angiogenesis.

Role of Uric Acid Metabolism-Related Inflammation in the Pathogenesis of Metabolic Syndrome Components Such as Atherosclerosis and Nonalcoholic Steatohepatitis

Uric acid (UA) is the end product of purine metabolism and can reportedly act as an antioxidant. However, recently, numerous clinical and basic research approaches have revealed close associations of hyperuricemia with several disorders, particularly those comprising the metabolic syndrome. In this review, we first outline the two molecular mechanisms underlying inflammation occurrence in relation to UA metabolism; one is inflammasome activation by UA crystallization and the other involves superoxide free radicals generated by xanthine oxidase (XO). Importantly, recent studies have demonstrated the therapeutic or preventive effects of XO inhibitors against atherosclerosis and nonalcoholic steatohepatitis, which were not previously considered to be related, at least not directly, to hyperuricemia. Such beneficial effects of XO inhibitors have been reported for other organs including the kidneys and the heart. Thus, a major portion of this review focuses on the relationships between UA metabolism and the development of atherosclerosis, nonalcoholic steatohepatitis, and related disorders. Although further studies are necessary, XO inhibitors are a potentially novel strategy for reducing the risk of many forms of organ failure characteristic of the metabolic syndrome.

Serum uric acid level as an indicator for CKD regression and progression in patients with type 2 diabetes mellitus-a 4.6-year cohort study

BACKGROUND

To investigate the association of serum uric acid level with renal function change in patients with type 2 diabetes mellitus (T2DM).

METHODS

T2DM patients who had been followed-up for at least 3 years were included. Participants were categorized into stable, progression, or regression groups according to their change in chronic kidney disease (CKD) stage. During the follow-up period, all numeric values of metabolic factors, including the uric acid level and the medication possession rate, were calculated in order to investigate their associations with CKD development. Multivariate Cox regression analyses were used to identify independent factors associated with change in CKD.

RESULTS

A total of 2367 T2DM patients were enrolled in this study and followed-up for a mean of 4.6 years. The numbers of patients in the stable, progression and regression groups were 1133 (47.9%), 487 (20.6%), and 747 (31.5%), respectively. The progression group had the highest serum uric acid level (6.9 ± 1.8 mg/dL), and the regression group had the lowest uric acid level (5.4 ± 1.5 mg/dL). In addition, we found that the serum uric acid level was an independent factor associated with CKD progression when the value exceeded 6.3 mg/dL. A lower uric acid level could be beneficial for CKD improvement in T2DM patients with stage 3-5 CKD.

CONCLUSIONS

Our data indicated that the serum uric acid level is associated with CKD regression and progression and suggested that a high normal serum uric acid level should be closely monitored in patients with T2DM. Copyright © 2015 John Wiley & Sons, Ltd.

Association of serum uric acid levels with the risk of development or progression of albuminuria among Japanese patients with type 2 diabetes: a prospective cohort study [Diabetes Distress and Care Registry at Tenri (DDCRT 10)]

AIMS

To assess the prospective association between baseline serum uric acid level and subsequent risk of development or progression in albuminuria.

METHODS

Longitudinal data were obtained from 2518 patients with type 2 diabetes in the development cohort and registered in a Japanese diabetes registry. To assess the independent correlations between baseline serum uric acid quartiles and either the development or progression of diabetic nephropathy for 2 years, the Cox proportional hazards model was used and adjusted for potential confounders.

RESULTS

The mean patient age, body mass index, and glycated hemoglobin (HbA1c) level were 66.1 years, 24.6 kg/m(2), and 7.5 % (57.6 mmol/mol), respectively. The baseline serum uric acid levels, with mean values of 3.6, 4.9, 5.8, and 7.3 mg/dL from the first to fourth quartiles, were significantly associated with the urinary albumin/creatinine ratio at baseline (p < 0.001). Baseline uric acid levels were not significantly associated with the development of nephropathy, but they were with the progression of nephropathy. The multivariable-adjusted hazards ratios for the progression from microalbuminuria to macroalbuminuria were 2.17 [95 % confidence interval (CI) 1.15-4.08; p = 0.016], 3.04 (95 % CI 1.67-5.53; p < 0.001), and 3.56 (95 % CI 1.83-6.93; p < 0.0011) for the first, third, and fourth quartiles of serum uric acid levels, respectively, as compared to that for the second quartile. We did not observe significant association between uric acid levels and change in estimated glomerular filtration rate.

CONCLUSIONS

Low and high serum uric levels, independent of possible confounders, were associated with a subsequent risk of progression, not development, in albuminuria in type 2 diabetes patients. Therefore, serum uric acid levels may be useful for predicting the future risk of progression of microalbuminuria.

Prediction of the effect on antihyperglycaemic action of sitagliptin by plasma active form glucagon-like peptide-1

AIM: To investigate whether active glucagon-like peptide-1 (GLP-1) is a prediction Factor of Effect of sitagliptin on patients with type 2 diabetes mellitus (GLP-1 FEST:UMIN000010645).

METHODS: Seventy-six patients with type 2 diabetes, who had insufficient glycemic control [Hemoglobin A1c (HbA1c) ≥ 7%] in spite of treatment with metformin and/or sulfonylurea, were included in the investigation. Patients were divided into three groups by tertiles of fasting plasma active GLP-1 level, before the administration of 50 mg sitagliptin.

RESULTS: At baseline, body mass index, serum UA, insulin and HOMA-IR were higher in the high active GLP-1 group than in the other two groups. The high active GLP-1 group did not show any decline of HbA1c (7.6% ± 1.4% to 7.5% ± 1.5%), whereas the middle and low groups indicated significant decline of HbA1c (7.4 ± 0.7 to 6.8 ± 0.6 and 7.4 ± 1.2 to 6.9 ± 1.3, respectively) during six months. Only the low and middle groups showed a significant increment of active GLP-1, C-peptide level, a decreased log and proinsulin/insulin ratio after administration. In logistic analysis, the low or middle group is a significant explanatory variable for an HbA1c decrease of ≥ 0.5%, and its odds ratio is 4.5 (1.40-17.6) (P = 0.01) against the high active GLP-1 group. This remains independent when adjusted for HbA1c level before administration, patients’ medical history, medications, insulin secretion and insulin resistance.

CONCLUSION: Plasma fasting active GLP-1 is an independent predictive marker for the efficacy of dipeptidyl peptidase 4 inhibitor sitagliptin.

Serum uric acid levels are associated with a high risk of rapid chronic kidney disease progression among patients with type 2 diabetes: a prospective cohort study [Diabetes Distress and Care Registry at Tenri (DDCRT 12)]

Background

We assessed the prospective association between baseline serum uric acid (SUA) concentrations and consequent risk of chronic kidney disease (CKD) progression in type 2 diabetes patients.

Methods

Longitudinal data from a Japanese diabetes registry including 3454 type 2 diabetes patients were obtained. To assess the independent correlations between SUA and rapid CKD progression [i.e., 30 % reduction in estimated glomerular filtration rate (eGFR) over 2 years], participants were divided into five groups based on SUA levels: <5.0, ≥5.0-6.0, ≥6.0-7.0, ≥7.0-8.0, and ≥8.0 mg/dl. Cox proportional hazards model adjusted for potential confounders was used for analysis.

Results

After 2 years, rapid CKD progression was recognized in 169 patients (4.89 %) who showed longer duration of type 2 diabetes (15.5 vs. 13.5 years, p = 0.005); higher systolic blood pressure (142.0 vs. 138.3 mmHg, p = 0.016), SUA (6.15 vs. 5.32 mg/dl, p < 0.001), and urinary albumin-creatinine ratio (1127.4 vs. 184.7 mg/gCr, p < 0.001); and lower diastolic blood pressure (69.7 vs. 72.8 mmHg, p = 0.003). Multivariate ratios for rapid CKD progression were 1.19 (p = 0.371), 1.02 (p = 0.937), 1.18 (p = 0.625), and 3.04 (p = 0.004), respectively, for the first, third, fourth, and fifth serum UA range groups; a second group was used as a reference.

Conclusions

Higher SUA levels, independent of possible confounders, were associated with rapid eGFR decline and CKD progression in type 2 diabetes patients. SUA may be a useful biomarker for predicting future risk of rapid diabetic CKD progression.

Linking uric acid metabolism to diabetic complications

Hyperuricemia have been thought to be caused by the ingestion of large amounts of purines, and prevention or treatment of hyperuricemia has intended to prevent gout. Xanthine dehydrogenase/xanthine oxidase (XDH/XO) is rate-limiting enzyme of uric acid generation, and allopurinol was developed as a uric acid (UA) generation inhibitor in the 1950s and has been routinely used for gout prevention since then. Serum UA levels are an important risk factor of disease progression for various diseases, including those related to lifestyle. Recently, other UA generation inhibitors such as febuxostat and topiroxostat were launched. The emergence of these novel medications has promoted new research in the field. Lifestyle-related diseases, such as metabolic syndrome or type 2 diabetes mellitus, often have a common pathological foundation. As such, hyperuricemia is often present among these patients. Many in vitro and animal studies have implicated inflammation and oxidative stress in UA metabolism and vascular injury because XDH/XO act as one of the major source of reactive oxygen species Many studies on UA levels and associated diseases implicate involvement of UA generation in disease onset and/or progression. Interventional studies for UA generation, not UA excretion revealed XDH/XO can be the therapeutic target for vascular injury and renal dysfunction. In this review, the relationship between UA metabolism and diabetic complications is highlighted.