Association between serum uric acid level and peripheral arterial disease

Effects of Colchicine on Major Adverse Limb and Cardiovascular Events in Patients With Peripheral Artery Disease

OBJECTIVE

To assess the effects of colchicine, which has been shown to reduce the risks of coronary artery disease but scarcely studied in peripheral artery disease (PAD), on major adverse limb events (MALE) in patients with PAD.

METHODS

This is a retrospective study based on a nationwide database. Patients who were diagnosed with PAD between 2010 and 2020 and prescribed with colchicine after the diagnosis of PAD were identified. Patients were then categorized into the colchicine or the control group according to drug use. Propensity score matching was performed to mitigate selection bias. Risks of MALE (including lower limb revascularization and nontraumatic amputation) and major adverse cardiovascular events were compared between the two groups.

RESULTS

After patient selection and propensity score matching, there were 60,219 patients in both colchicine and control groups. After a mean follow-up of 4.5 years, the risk of MALE was significantly lower in the colchicine group compared with control (subdistribution HR, 0.75; 95% CI, 0.71 to 0.80), as were the incidence of both components of MALE, lower limb revascularization and major amputations. Colchicine treatment was also associated with lower risk of cardiovascular death. The lower risk of MALE observed with colchicine therapy was accentuated in the subgroup of patients receiving concomitant urate-lowering medications.

CONCLUSION

In patients diagnosed with PAD, the use of colchicine is associated with lower risks of MALE and cardiovascular death. Anti-inflammatory therapy with colchicine may provide benefits in vascular beds beyond the coronary arteries.

Impact of hyperuricemia on 5-year clinical outcomes following percutaneous transluminal angioplasty

BACKGROUND

Although the correlation between hyperuricemia and cardiovascular disease (CVD) is well known, there have been limited data regarding the impact of hyperuricemia on long-term clinical outcomes in patients with peripheral arterial disease (PAD) after percutaneous transluminal angioplasty (PTA).

METHODS

A total of 718 patients who underwent PTA for PAD were enrolled. The patients were divided into the hyperuricemia group (N = 168) and the normal group (N = 550). Hyperuricemia was defined as a uric acid level ≥ 7.0 mg/dL in men, and ≥ 6.5 mg/dL in women. The primary endpoint was major adverse cerebral and cardiovascular event (MACCE), including death, myocardial infarction (MI), any coronary revascularization, and stroke, up to 5 years. The secondary endpoint was major adverse limb event (MALE), including any repeated PTA, and target extremity surgery (TES). Inverse probability weighting (IPTW) analysis, derived from the logistic regression model, was performed to adjust potential confounders.

RESULTS

After IPTW matching analysis, compared to the normal group, the hyperuricemia group was not associated with increased MACCE but was associated with an increased incidence of MI (2.6 % vs. 0.5 %, p = 0.001), and coronary revascularization (6.7 % vs. 3.9 %, p = 0.018). Also, the hyperuricemia group was associated with a higher incidence of MALE (45.3 % vs. 28.9 %, p < 0.001), including target extremity revascularization (TER; 25.1 % vs. 15.9 %, p < 0.001), non-TER (11.5 % vs. 5.6 %, p < 0.001), and TES (22.8 % vs. 16.2 %, p = 0.002).

CONCLUSIONS

In the present study, hyperuricemia was associated with worse clinical outcomes in PAD patients following PTA during 5-year clinical follow-up. Further investigations should be made regarding the clinical benefit of controlling hyperuricemia on clinical outcomes.

Impact of hyperuricemia on 5-year clinical outcomes in patients with critical limb ischemia following percutaneous transluminal angioplasty

BACKGROUND

A growing evidence on the correlation between hyperuricemia and cardiovascular disease (CVD) has been previously reported. However, there have been limited data on the impact of hyperuricemia on long-term clinical outcomes in patients with critical limb ischemia (CLI) who underwent percutaneous transluminal angioplasty (PTA).

METHODS

A total of 425 peripheral artery disease patients who underwent PTA for CLI were enrolled. The patients were divided into the hyperuricemia group (n = 101) and the normal group (n = 324). The primary endpoint was major adverse cerebral and cardiovascular event (MACCE), including death, myocardial infarction, any coronary revascularization, and stroke, up to 5 years. The secondary endpoint was a major adverse limb event (MALE), including any repeated PTA, and target extremity surgery. Inverse probability weighting (IPTW) analysis, derived from the logistic regression model, was performed to adjust for potential confounders.

RESULTS

After IPTW matching analysis, compared to the normal group, the hyperuricemia group was associated with a higher incidence of MACCE (20.7% vs. 13.6%, hazard ratio [HR], 1.65; 95% confidence interval [CI], 1.15-2.38, P  = 0.006) including non-cardiac death (11.7% vs. 6.3%, HR: 1.95, 95% CI: 1.19-3.19, P  = 0.006) and MALE (47.7% vs. 36.0%, HR: 1.62, 95% CI: 1.23-2.13, P  = 0.001) including non-target extremity revascularization (15.0% vs. 6.8%, HR: 2.42, 95% CI: 1.52-3.84, P  < 0.001).

CONCLUSION

In the present study, hyperuricemia was associated with worse clinical outcomes in patients with CLI following PTA during 5-year clinical follow-up. Efficacy of controlling hyperuricemia in improving clinical outcomes should be evaluated in further studies.

Risk factors for peripheral artery disease and diabetic peripheral neuropathy among patients with type 2 diabetes

AIMS

To investigate the prevalence of peripheral artery disease (PAD) and diabetic peripheral neuropathy (DPN) and the associated risk factors among Chinese patients with type 2 diabetes mellitus.

METHODS

A cross-sectional study was conducted using data between November 1, 2018, and December 31, 2022. PAD was defined as ABI ≤ 0.9. DPN diagnosis involved specialized physician assessments using questionnaires and vibration perception threshold tests. Logistic regression analysis was used to identify related factors. We also evaluated the association between the clustering of risk factors and disease incidence.

RESULTS

The study population comprised 13,315 patients (mean age: 63.3 years). 4.9 % of the patients had PAD and 43.9 % had DPN. Multivariate regression analysis revealed advanced age, smoking, hypertension, coronary heart disease, dyslipidemia, elevated HbA1c, and uric acid levels as independent risk factors for PAD. For DPN, independent risk factors included advanced age, female gender, hypertension, coronary heart disease, elevated total cholesterol, triglycerides, lipoprotein(a), fasting plasma glucose, HbA1c, alkaline phosphatase, cystatin C, albumin-to-creatinine ratio, and elevated homocysteine levels, whereas apolipoprotein A was a protective factor. The clustering of risk factors was prevalent and associated with higher disease risk.

CONCLUSIONS

Our study contributed to identifying high-risk individuals and improving lower limb health among diabetic individuals.

Association between serum uric acid levels and peripheral artery disease in Chinese adults with hypertension

Background

Higher serum uric acid (SUA) can cause gout, which is principally characterized by arthritis due to monosodium urate crystal deposition in the lower extremities. High levels of SUA have been linked to endothelial dysfunction, oxidative stress, and inflammation, all of which are involved in the pathogenesis of peripheral artery disease(PAD). To date, the relationship between SUA levels and PAD is still poorly understood.

Method

An analysis of 9,839 Chinese adults with essential hypertension from the ongoing China H-type Hypertension Registry Study was conducted in this cross-sectional study. Patients with an ABI ≤0.9 was diagnosed with PAD. Hyperuricemia was defined as SUA levels >420 mol/L in men and >360 mol/L in women. The association between SUA levels and PAD was evaluated using multivariable logistic regression models based on odds ratios (ORs) and their 95% confidence intervals (CIs).

Results

The enrolled subjects ranged in age from 27 to 93 years, with a mean age of 63.14 ± 8.99 years. The proportion of male patients was 46.22%, and the prevalence of hyperuricemia was 50.72%. In males, hyperuricemia was positively associated with the risk of PAD (adjusted OR per SD increase: 1.72, 95% CI 1.17 to 2.53, P =0.006). Males in the highest SUA tertile were significantly more likely to have PAD (adjusted OR: 2.63, 95% CI 1.42 to 4.86, P = 0.002; P for trend = 0.001). However, this positive relationship was not observed in females (adjusted OR: 1.29, 95% CI 0.77 to 2.17, P = 0.327; P for trend = 0.347).

Conclusion

According to this cross-sectional study, higher SUA levels were positively associated with PAD in male hypertensive patients, while this positive relationship disappeared in female participants.

C-reactive Protein, Free Fatty Acid, and Uric Acid as Predictors of Adverse Events after Endovascular Revascularization of Arterial Femoropopliteal Occlusion Lesions

OBJECTIVES

This study aimed to investigate the relationship between pre-procedure high-sensitivity C-reactive protein (hsCRP), free fatty acid (FFA), and uric acid (UA) levels and post-procedure mortality and morbidity of endovascular revascularization of arterial femoropopliteal occlusion lesions.

METHODS

This was a retrospective review of clinical data retrieved from a prospectively held database in Peking Union Medical College Hospital. A total of 71 Patients who underwent endovascular treatment (EVT) for femoropopliteal occlusive disease between January 1, 2014 and November 1, 2017, were included in this study. Endpoints were defined as major adverse limb events (MALE; target vessel revascularization, amputation, or disease progression) and major adverse cardiovascular events (MACE; stroke, myocardial infarction, or all-cause death) during the entire follow-up period. Univariate and multivariate Cox proportional hazards regression models were used to evaluate the relationship of elevated biomarker levels (hsCRP, FFA and UA, measured by immunoturbidimetry assay, enzymatic assay and enzymatic assay, respectively) to MALE and MACE outcomes.

RESULTS

Seventy-one patients (72 limbs) with sufficient follow-up information were included in the analysis. The mean age was 69.7 ± 8.6 years; 21.1% were female. The Rutherford class of target limbs were ≥ 3. The median follow-up was 36 (range 18-59 months). Univariate analyses revealed that patients with elevated hsCRP levels had an increased risk of MALE (hazard ratio [HR], 2.682; 95% confidence interval [CI], 1.281-5.617, P = 0.009). High FFA levels were associated with an increased risk of MALE (HR, 2.658; 95% CI, 1.075-6.573; P = 0.034). Multivariate analyses demonstrated that elevated hsCRP values (HR, 4.015; 95% CI, 1.628-10.551; P = 0.003) and FFA value (HR, 3.034; 95% CI, 1.102-8.354; P = 0.032) were both significantly associated with increased MALE. Elevated UA levels predicted MACE in the presence of confounders (HR, 11.446; 95% CI, 1.367-95.801 P = 0.023).

CONCLUSION

Pre-procedure hsCRP and FFA levels could serve as predictors of adverse events after EVT in patients with arterial femoropopliteal occlusive disease. The role of UA in MACE may warrant further investigation, because the correlation is not as powerful as the other two in the study.

Relationship between serum uric acid, all-cause mortality and cardiovascular mortality in peritoneal dialysis patients: systematic review and meta-analysis of cohort studies

OBJECTIVES

To analyse the relationship between serum uric acid (SUA), all-cause and cardiovascular (CV) mortality in peritoneal dialysis (PD) patients to inform clinical practice and future research.

DESIGN

A systematic review of observational studies.

DATA SOURCES

PubMed, Embase, Web of Science, the Cochrane Library, China National Knowledge Infrastructure (CNKI), SinoMed, Chinese Science and Technology Journal Database (VIP) and Wan Fang databases were searched from their inception to January 2021 for cohort and case-control studies reporting SUA and mortality in patients with PD.

METHODS

The Newcastle-Ottawa Quality Assessment Scale was used to appraise quality of cohort and case-control studies. Effect estimates were presented as HRs with 95% CIs in a meta-analysis using STATA V.16.0. Data not suitable for pooling were synthesised qualitatively.

RESULTS

Fourteen cohort studies with 24 022 patients were included. No case-control studies were identified. For prospective cohort studies, pooled results for the highest SUA category were significantly greater than the lowest for all-cause (one study; 1278participants; HR 1.79; 95% CI 1.17 to 2.75) and CV mortality (one study; 1278 participants; HR 2.63; 1.62-4.27). An increase of 1 mg/dL in SUA level was associated with a 16% increased risk of all-cause mortality (one study; 1278 participants; HR 1.16; 1.03-1.32) and 34% increased CV mortality risk (one study; 1278 participants; HR 1.34; 1.16-1.55). For retrospective cohort studies, the highest SUA category did not demonstrate an elevated all-cause (five studies; 4570 participants; HR 1.09; 0.70-1.70) or CV mortality (three studies; 3748 participants; HR 1.00; 0.44-2.31) compared with the lowest SUA category. Additionally, there was no increase in all-cause (eight studies; 11 541 participants; HR 0.94; 0.88-1.02) or CV mortality (three studies; 7427 participants; HR 0.90; 0.76-1.06) for every 1 mg/dL increase in SUA level.

CONCLUSIONS

Results of prospective and retrospective cohort studies were inconsistent. Consequently, prospective, multicentre, long-term follow-up studies are required to confirm the relationship between SUA and mortality in patients with PD.

Associations of Serum Uric Acid Levels With Macrovascular and Renal Microvascular Dysfunction Among Individuals From Sub-Saharan Africa

IMPORTANCE

Serum uric acid (SUA) level is associated with vascular dysfunction in Eurasian populations, but little is known about this association in individuals from sub-Saharan Africa, who have a high prevalence of both relatively high SUA levels and vascular dysfunction.

OBJECTIVES

To assess the associations of SUA levels with macrovascular and kidney microvascular dysfunction in individuals of sub-Saharan African ancestry and evaluate potential factors that could mediate these associations.

DESIGN, SETTING, AND PARTICIPANTS

Cross-sectional analyses of baseline data from the multicenter Research on Obesity and Diabetes Among African Migrants study, conducted from 2012 to 2015, were performed from January to March 2021. The population included Ghanaian individuals living in Ghana and Europe.

EXPOSURE

Abnormal SUA levels.

MAIN OUTCOMES AND MEASURES

Logistic regression was used to examine the associations of SUA level quartiles with microvascular (albuminuria) and macrovascular (peripheral artery disease and coronary artery disease) dysfunction, with adjustments for age, sex, estimated glomerular filtration rate, site of residence, socioeconomic status, alcohol, smoking, diabetes, hypertension, waist-hip ratio, and total cholesterol level. Mediation analysis was performed to assess whether the association was via elevated blood pressure, hemoglobin A1c, and high-sensitivity C-reactive protein levels or via weight-hip ratio. The research questions were formulated after data collection.

RESULTS

A total of 4919 Ghanaian individuals (3047 [61.9%] women) aged 25-75 years (mean [SD], 46.26 [11.08] years) were included. There was a significant positive association between SUA quartiles and albuminuria, but not coronary artery disease or peripheral artery disease, after adjustment for covariates. After full adjustment, individuals in the fourth SUA quartile had higher odds of albuminuria (adjusted odds ratio [aOR], 1.54; 95% CI, 1.07-2.21), but not peripheral artery disease (aOR, 1.35; 95% CI, 0.87-2.08) or coronary artery disease (aOR, 1.09; 95% CI, 0.77-1.55), compared with individuals in the first quartile. After full adjustment, systolic and diastolic blood pressure significantly mediated the association between SUA concentrations and albuminuria, accounting for 19.4% of the total association for systolic and 17.2% for diastolic blood pressure; hemoglobin A1c, high-sensitivity C-reactive protein, and waist-hip ratio did not mediate this association.

CONCLUSIONS AND RELEVANCE

In this cross-sectional study among a sub-Saharan African population, elevated SUA levels were significantly associated with kidney microvascular dysfunction and mediated partly through elevated blood pressure. These findings suggest that individuals from sub-Saharan Africa with elevated SUA levels may benefit from periodic screening for kidney microvascular dysfunction to aid early detection or treatment.

Associations between Serum Vitamins and Serum Uric Acid in a Population of Shenyang, China

Previous studies have demonstrated that serum vitamins are associated with serum uric acid (SUA) level. However, no study has comprehensively investigated whether various serum vitamins are associated with SUA level in a general population. Thus, a cross-sectional study was designed to explore the associations between SUA level and serum vitamins. The data of this study for SUA levels were collected from participants aged ≥18 y. Serum vitamin and other baseline information, including age and body mass index, was determined. Moreover, associations between SUA level and serum vitamins were explored using analysis of covariance. Higher levels of SUA were significantly associated with a higher level of serum vitamins A, B9 and B5 (p<0.05). Higher level of SUA were associated with a lower level of serum vitamins C, and D2 (p<0.05). No significant associations were found between vitamins C, and D2 and SUA levels after adjustment. Study results suggested that serum vitamins A, B9 and B5 were positively associated, whereas serum vitamins C, and D2 were inversely associated with SUA levels.

Serum Uric Acid and Left Ventricular Mass in Essential Hypertension

Serum uric acid (sUA) has been associated with cardiovascular risk. Although the recent mechanistic hypothesis poses the basis for the association between sUA and left ventricular mass index (LVMi), the issue remains poorly investigated in a clinical setup. Through a retrospective analysis of the database of the departmental Hypertension Clinic of University Hospital of Salerno Medical School, we identified 177 essential hypertensives (age 60.3 ± 13.3 years; 85 men), free from uric acid-modulating medications and severe chronic kidney disease, and whose sUA values, anthropometric, clinical, and echocardiographic data were available. In the studied cohort, the average duration of hypertension was 8.4 ± 7.1 years. LVMi associated with classical determinants, such as age, blood pressure, and kidney function, although after multivariate correction, only age remained significant. Also, sUA correlated positively with LVMi, as well as body size, metabolism, and kidney function. In a multivariate analysis, sUA confirmed the independent association with LVMi. Also, levels of sUA >5.6 mg/dl are associated with larger cardiac size. We confirmed our data in a replicate analysis performed in a larger population (1,379 hypertensives) from an independent clinic. Our results demonstrate that sUA increases with LVMi, and a cutoff of 5.6 mg/dl predict larger LV sizes. Our data suggest that hyperuricemia might help to stratify the risk of larger cardiac size in hypertensives.

Hyperuricemia Is Associated with Left Ventricular Dysfunction and Inappropriate Left Ventricular Mass in Chronic Kidney Disease

Background. Hyperuricemia is common in patients with chronic kidney disease (CKD), and this may lead to poor cardiovascular (CV) outcomes. The aim of this cross-sectional study was to assess associations among serum uric acid (UA) and echocardiographic parameters, ankle-brachial index (ABI), and brachial-ankle pulse wave velocity (baPWV) in patients with CKD. Methods. A total of 418 patients with CKD were included. The echocardiographic measurements included left atrial diameter (LAD), left ventricular ejection fraction (LVEF) and the ratio of observed to predict left ventricular mass (LVM). ABI, baPWV and medical records were obtained. Results. Multivariable forward logistic regression analysis showed that a high UA level was significantly associated with LAD > 47 mm (odds ratio [OR], 1.329; p = 0.002), observed/predicted LVM > 128% (OR, 1.198; p = 0.008) and LVEF < 50% (OR, 1.316; p = 0.002). No significant associations were found between UA and ABI < 0.9 or baPWV > 1822 cm/s. Multivariate stepwise linear regression analysis showed that a high UA level correlated with high LAD (unstandardized coefficient β, 0.767; p < 0.001), high observed/predicted LVM (unstandardized coefficient β, 4.791; p < 0.001) and low LVEF (unstandardized coefficient β, −1.126; p = 0.001). No significant associations between UA and low ABI and high baPWV were found. Conclusion. A high serum UA level was associated with a high LAD, high observed/predicted LVM and low LVEF in the patients with CKD. A high serum UA level may be correlated with abnormal echocardiographic parameters in patients with stage 3–5 CKD.

Association between serum uric acid and large-nerve fiber dysfunction in type 2 diabetes: a cross-sectional study

Background

Large-nerve fiber dysfunction, as assessed by vibration perception threshold (VPT) predicts risks of ulceration, amputation, and mortality in diabetes. Serum uric acid (UA) is closely associated with various metabolic disorders, especially diabetes. Thus, we sought to investigate the clinical relevance of UA to large-nerve fiber dysfunction, among patients with type 2 diabetes (T2D).

Methods

Medical records of consecutive patients with T2D who were admitted to Beijing Friendship Hospital Pinggu Campus between May 2014 and December 2016 were collected. Data for the 824 eligible patients included in the final analysis were extracted using a structured form. A VPT value ≥15 in either foot was defined as abnormal. We compared the clinical characteristics between patients with abnormal VPT and those with normal VPT (VPT value <15 in both feet) in the overall population and in gender subgroups. Logistic regression analysis was performed to explore the association of abnormal VPT with UA level. One-way analysis of variance was used to compare VPT values across four UA quartiles.

Results

UA levels were significantly lower in T2D patients with abnormal VPT than in those with normal VPT (294.5 ± 84.0 vs. 314.9 ± 92.8 μmol/L, P < 0.01), especially among male patients (311.7 ± 85.2 vs. 336.9 ± 89.6 μmol/L, P < 0.01). From the logistic regression analysis, hyperuricemia (males >420 μmol/L; females >360 μmol/L) was associated with a reduced risk of abnormal VPT (odds ratio [OR], 0.60; 95% confidence interval [CI], 0.39–0.91; P < 0.05). This association was robust in male patients (OR, 0.43; 95% CI, 0.24–0.76; P < 0.01) but not in female patients (OR, 0.92; 95% CI, 0.47–1.82; P = 0.816), even after adjustment for confounding factors. For the younger male subgroup (age <65 years), VPT values decreased as the UA level increased (P for trend = 0.002), but this trend was not significant in older male subgroup (age ≥65 years; P for trend = 0.400).

Conclusions

Low serum UA levels showed a significant association with an increased risk of large-nerve fiber dysfunction in male patients with T2D, but not in female patients with T2D. In addition, in only the younger subgroup of male patients (<65 years), lower levels of UA also correlated with higher VPT values.

High serum uric acid level is a mortality risk factor in peritoneal dialysis patients: a retrospective cohort study

Background

The results remain controversial with regards to the impact of serum uric acid on clinical outcomes from peritoneal dialysis population. The aim of our study was to investigate the influence of serum uric acid levels on mortality in peritoneal dialysis patients.

Methods

Data on 9405 peritoneal dialysis patients from the Zhejiang Renal Data system were retrospectively analyzed. All demographic and laboratory data were recorded at baseline. The study cohort was divided into quintiles according to baseline uric acid level (mg/dL): Q1 (< 6.06), Q2 (6.06–6.67), Q3 (6.68–7.27) (reference), Q4 (7.28–8.03), and Q5 (≥8.04). Hazards ratio (HR) of all-cause and cardiovascular mortality was calculated.

Results

Mean serum uric acid was 7.07 ± 1.25 mg/dL. During a median follow-up of 29.4 (range, 3.0 to 115.4) months, 1226 (13.0%) patients died, of which 515 (5.5%) died of cardiovascular events. The Kaplan-Meier survival curves showed that patients in the middle uric acid quintile (Q3: 6.68–7.27) exhibited the highest patient and cardiovascular survival rates (log-rank test P < 0.05). Multivariate Cox regression analysis showed that, using Q3 as the reference, in the fully adjusted model, a higher uric acid level (Q4: 7.28–8.03, and Q5: ≥8.04) was significantly associated with higher all-cause mortality (Model 3; Q4: HR, 1.335, 95% CI, 1.073 to 1.662, P = 0.009; Q5: HR, 1.482, 95% CI, 1.187 to 1.849, P = 0.001), but not with cardiovascular mortality. The adverse effect of higher uric acid level (≥7.28 mg/dL) on all-cause mortality was more prominent in groups such as male, hypoalbuminemia, normal weight, non-diabetes mellitus at baseline rather than in their counterparts respectively.

Conclusions

A higher uric acid level was an independent risk factor for all-cause mortality in peritoneal dialysis patients.

Electronic supplementary material

The online version of this article (10.1186/s12986-019-0379-y) contains supplementary material, which is available to authorized users.

Association of overweight and obesity with cardiovascular risk factors in patients with atherosclerotic diseases

Background

The aim of this study was to compare demographic, clinical and biochemical characteristics, including inflammatory markers, according to the nutritional status of patients with verified atherosclerotic disease.

Methods

This cross-sectional study involved 1045 consecutive patients with verified carotid disease or peripheral arterial disease (PAD). Anthropometric parameters and data on cardiovascular risk factors and therapy for hypertension and hyperlipidemia were collected for all participants.

Results

Carotid disease was positively and PAD was negatively associated with body mass index (BMI). Negative association between obesity and PAD was significant only in former smokers, not in current smokers or in patients who never smoked. Overweight and general obesity were significantly related to metabolic syndrome (p < 0.001), lower values of high - density lipoprotein cholesterol (p < 0.001), increased triglycerides (p < 0.001), hyperglycemia (p < 0.001), self-reported diabetes (p < 0.001), hypertension (p < 0.001), high serum uric acid (p < 0.001), increased high sensitivity C-reactive protein (p = 0.020) and former smoking (p = 0.005) after adjustment for age, gender and type of disease. Antihypertensive therapy seems to be less effective in patients who are overweight and obese.

Conclusions

In conclusion, overweight and general obesity were significantly related to several cardiovascular risk factors.

Longitudinal association between serum uric acid levels and multiterritorial atherosclerosis

Multiterritorial atherosclerosis has dramatically increased annual risk of adverse cardiovascular events than atherosclerotic disease with single-artery affected. Serum uric acid (SUA) is an important predictor of stroke and atherosclerosis; however, which is supported by few direct evidence based on cohort studies. A prospective cohort study including 2644 North Chinese adults aged ≥40 years was performed in 2010-2012 to investigate the association between SUA and multiterritorial vascular stenosis. Hyperuricaemia was defined as SUA levels >6 and >7 mg/dL for males and females, respectively. All participants underwent twice transcranial Doppler (TCD) and bilateral carotid duplex ultrasound to evaluate intracranial artery stenosis (ICAS) and extracranial arterial stenosis (ECAS) and peripheral arterial disease (PAD) was determined by ankle-brachial index (ABI) on January 2010 and January 2012 based on regular health check-ups. The cumulative incidence of vascular stenosis was significantly higher in subjects with hyperuricaemia than in those without hyperuricaemia (54.1% vs. 34.7%, P < 0.001). The adjusted odds ratios (ORs) with 95% confidence intervals (CIs) for new on-set vascular stenosis due to hyperuricaemia and a 1-mg/dL change in SUA level were 1.75 (1.32-2.31) and 1.29 (1.21-1.38), respectively. Furthermore, in the gender-stratified analysis, the association between SUA levels and ICAS was statistically significant in males (OR: 2.02; 95% CI: 1.18-3.46), but not females (OR: 0.85, 95% CI: 0.41-1.76, P for interaction: 0.026).

Different-shaped curves for serum uric acid with and without diabetes: Results from China Health and Retirement Longitudinal Study

BACKGROUND

Several studies have revealed conflicting results regarding the relationship between serum uric acid (SUA) and blood glucose concentrations. The aim of this study was to identify the shape of the curve between SUA and either fasting plasma glucose (FPG) or HbA1c in diabetic and non-diabetic participants.

METHODS

This cross-sectional study of the relationship between SUA and diabetes and non-diabetes was conducted in 10 266 participants. Data from the national baseline survey of the China Health and Retirement Longitudinal Study (CHARLS; 2011-12) were used. Restrictive cubic spline regression and two piecewise linear regression models were used to detect non-linear trends and calculate the slope of each segment.

RESULTS

After adjusting for all confounding factors in all subjects, an L-shaped relationship was found between FPG and SUA in males (β₂  = 3.47, P < 0.01) and females (β₂  = 5.84, P < 0.01), as well as between HbA1c and SUA in males (β₂  = 0.10, P = 0.03) and females (β₂  = 0.12, P = 0.02). In non-diabetic individuals, there was a positive linear correlation between FPG and SUA in females (β = 0.62, P = 0.02). After a diagnosis of diabetes, a negative linear relationship was found between SUA and blood glucose in males, and a nearly L-shaped curve was found in females.

CONCLUSIONS

An L-shaped association was found between SUA and blood glucose in both genders. Stratified analysis revealed an L-shaped curve only in diabetic females. Further studies are warranted to investigate the mechanisms of the association between uric acid and blood glucose levels.

Blockage of macrophage migration inhibitory factor (MIF) suppressed uric acid-induced vascular inflammation, smooth muscle cell de-differentiation, and remodeling

Hyperuricemia contributes to vascular injury and dysfunction, yet the potential mechanisms are not well understood. Uric acid (UA) has been found to stimulate macrophage migration inhibitory factor (MIF) up-regulation in renal tubules from rats subjected to UA-induced nephropathy. Given that MIF is able to induce vascular smooth muscle cell (VSMC) de-differentiation (from contractile state to a secretory state), we thus hypothesized that UA-induced vascular injury is via up-regulating of MIF in VSMCs, which enhancing vascular inflammation and VSMC transition. Within a mouse model of UA injection (500 mg/kg, twice/day, 14 days), we measured circulating and vascular MIF levels under UA stimulation at 6 h, day 1, and 14. We tested the efficacy of MIF inhibitor (10 mg/kg, twice/day, 14 days) on UA-induced vascular inflammation and remodeling. High plasma level of UA induced vascular MIF release into the plasma at acute phase. In the chronic phase, the protein level of MIF is up-regulated in the vessels. MIF inhibitor suppressed vascular inflammatory responses, repressed VSMC de-differentiation, and attenuated vascular remodeling and dysfunction following UA stimulation. Knockdown of MIF in cultured VSMCs repressed UA-induced de-differentiation. Our results provided a novel mechanism for MIF-mediated vascular injury in response to UA stimulation, and suggested that anti-MIF interventions may be of therapeutic value in hyperuricemic patients.

Uric acid induced inflammatory responses in endothelial cells via up-regulating(pro)renin receptor

Hyperuricemia is an important risk factor for vascular inflammation, yet the potential mechanisms of uric acid (UA) in endothelial cells are not well understood. UA has been found to stimulate renin-angiotensin system (RAS) activation in human umbilical vein endothelial cells (HUVECs). (Pro)renin receptor ((P)RR) is widely expressed in endothelial cells and able to induce RAS activation. Whether UA-induced endothelial cell inflammation is via up-regulating (P)RR remained unknown. Primary HUVECs were cultured and treated with UA, under the condition of (P)RR or AT1 silencing. The degree of inflammation in HUVECs was determined by Real-time PCR and monocyte adhesion assay. The protein levels of (P)RR were determined by western blotting or immunofluorescence. Probenecid was used to block UA re-absorption in this study. Adhesion of monocytes to HUVECs was elucidated by microfluidic chip. We found (P)RR is up-regulated in HUVECs following UA stimulation. UA promoted vascular inflammation, which was characterized by up-regulating of cytokines and enhanced monocyte adhesion. Silencing of (P)RR alleviated UA-induced vascular inflammation. Probenecid treatment abolished UA-induced vascular inflammation in HUVECs via suppressing (P)RR up-regulation. This finding was further verified by using microfluidic chip. Our findings indicate that (P)RR plays a critical role in endothelial inflammation in response to UA stimulation.

Relation of serum uric acid to asymptomatic proximal extracranial artery stenosis in a middle-aged Chinese population: a community-based cross-sectional study

OBJECTIVE

Serum uric acid (SUA) has been associated with cardiovascular diseases, including atherosclerosis and carotid artery stenosis. However, data on the relationship between SUA level and proximal extracranial artery stenosis (PEAS) are limited. Therefore, this study investigates the association between SUA levels and the risk of PEAS in asymptomatic Chinese population.

SETTING

This community-based cross-sectional study was conducted in Jidong Community Hospital, Tangshan, Hebei, China between July 2013 and August 2014.

PARTICIPANTS

The study examined 3325 asymptomatic participants (40-60 years) to evaluate the risk of PEAS.

RESULTS

For the participants stratified into quartiles based on gender-specific SUA levels, the prevalence of PEAS increased from Q1 to Q4 from 12.3% to 29.8% in the vertebral artery (VA), and from 2.8% to 5.8% in the common carotid artery. The proportion of PEAS relative to the detected number of arterial stenosis was lower in Q1 than in Q2-Q4. The multivariable ORs and 95% CI of PEAS in the second through fourth compared with the lowest quartiles for arterial stenosis were 1.278 (0.980 to 1.665), 1.117 (0.851 to 1.468) and 1.375 (1.033 to 1.830) (p_trend=0.0399); and for VA stenosis, 1.285 (0.966 to 1.709), 1.085 (0.808 to 1.457) and 1.439 (1.061 to 1.952) (p_trend=0.0235).

CONCLUSION

Elevated SUA concentration is significantly associated with PEAS in an asymptomatic middle-aged Chinese population, and vertebral arteries appeared to be the most vulnerable vessels.

An association of smoking with serum urate and gout: A health paradox

BACKGROUND

The potential effect of cigarette smoking on levels of serum urate and risk of gout has been considered by a large number of studies, either as the primary variable of interest or as a covariate.

METHODS

Here we systematically review the published evidence relating to the relationship of smoking with serum urate, hyperuricaemia, and gout.

RESULTS

Many studies have reported that smoking reduces serum urate, however, the evidence has not been conclusive with other studies pointing to the opposite or no effect. It has also been suggested that smoking reduces the risk of gout, although there is some evidence to contradict this finding.

CONCLUSION

A consensus has yet to be reached as to the effect of smoking on serum urate levels and the risk of gout.

Prevalence of peripheral artery disease (PAD) and factors associated: An epidemiological analysis from the population-based Screening PRE-diabetes and type 2 DIAbetes (SPREDIA-2) study

AIM

To describe the prevalence of Peripheral Artery Disease (PAD) in a random population sample and to evaluate its relationship with Mediterranean diet and with other potential cardiovascular risk factors such as serum uric acid and pulse pressure in individuals ranged 45 to 74 years.

METHODS

Cross-sectional analysis of 1568 subjects (mean age 6.5 years, 43% males), randomly selected from the population. A fasting blood sample was obtained to determine glucose, lipids, and HbA1C levels. An oral glucose tolerance test was performed in non-diabetic subjects. PAD was evaluated by ankle-brachial index and/or having a prior diagnosis.

RESULTS

PAD prevalence was 3.81% (95% CI, 2.97-4.87) for all participants. In men, PAD prevalence was significantly higher than in women [5.17% (95% CI, 3.74-7.11) vs. 2.78% (95% CI, 1.89-4.07); p = 0.014]. Serum uric acid in the upper quartile was associated with the highest odds ratio (OR) of PAD (for uric acid > 6.1 mg/dl, OR = 4.31; 95% CI, 1.49-12.44). The remaining variables more strongly associated with PAD were: Heart rate >90 bpm (OR = 4.16; 95%CI, 1.62-10.65), pulse pressure in the upper quartile (≥ 54 mmHg) (OR = 3.82; 95%CI, 1.50-9.71), adherence to Mediterranean diet (OR = 2.73; 95% CI, 1.48-5.04), and former smoker status (OR = 2.04; 95%CI, 1.00-4.16).

CONCLUSIONS

Our results show the existence of a low prevalence of peripheral artery disease in a population aged 45-74 years. Serum uric acid, pulse pressure and heart rate >90 bpm were strongly associated with peripheral artery disease. The direct association between Mediterranean diet and peripheral artery disease that we have found should be evaluated through a follow-up study under clinical practice conditions.

Asymptomatic hyperuricemia is independently associated with coronary artery calcification in the absence of overt coronary artery disease: A single-center cross-sectional study

Recently, the pathogenic role of uric acid (UA) in both systemic metabolic and atherosclerotic diseases has been investigated. We sought to determine the independent correlation between serum UA levels and coronary artery calcification, as a marker of subclinical atherosclerosis. A total of 4188 individuals without prior coronary artery disease or urate-deposition disease were included. All of the participants underwent multidetector computed tomography (MDCT) for the evaluation of coronary artery calcification (CAC) during their health check-ups. The subjects were divided into thre groups according to CAC scores (group 1: 0; group 2: 1-299; group 3: ≥300). After controlling for other confounders, serum UA levels were found to be positively associated with increasing CAC scores (P = 0.001). Adjusted mean serum UA levels in each CAC group were estimated to be 5.2 ± 0.1 mg/dL, 5.3 ± 0.1 mg/dL, and 5.6 ± 0.2 mg/dL from groups 1, 2, and 3, respectively. Subsequent subgroup analyses revealed that this positive association was only significant in participants who were male, relatively older, less overweight, and did not have diabetes mellitus (DM), hypertension, smoking history, or renal dysfunction. In conclusion, serum uric acid levels were independently associated with CAC score severity and this finding is particularly relevant to the subjects who were male, relatively older, less overweight (body mass index < 25 kg/m), and without a history of DM, hypertension, smoking, or renal dysfunction.

Association of Serum Uric Acid Levels with Leg Ischemia in Patients with Peripheral Arterial Disease after Treatment

Aim: We investigated the relationships of serum uric acid levels with the progression of atherosclerosis in patients with peripheral arterial disease (PAD) after treatment.

Methods: Subjects were male patients diagnosed with PAD. Atherosclerosis at the common carotid artery was evaluated based on its intima-media thickness (IMT). Leg arterial flow was evaluated by measuring ankle-brachial index (ABI) and exercise-induced decrease in ABI.

Results: Among various risk factors including age, blood pressure, adiposity, estimated glomerular filtration rate, and blood lipid, blood glucose, uric acid, fibrinogen and C-reactive protein levels, only uric acid levels showed significant correlations with ABI [Pearson's correlation coefficient, −0.292 (p < 0.01)] and leg exercise-induced decrease in ABI [Pearson's correlation coefficient, 0.236 (p < 0.05)]. However, there was no significant correlation between uric acid levels and maximum or mean IMT. Odds ratios of subjects with the 3rd tertile versus subjects with the 1st tertile for uric acid levels were significantly higher than the reference level of 1.00 for low ABI [4.44 (95% confidence interval, 1.45–13.65, p < 0.01)] and for high % decrease in ABI after exercise [4.31 (95% confidence interval, 1.34–13.82, p < 0.05)]. The associations of uric acid levels with the indicators of leg ischemia were also found after adjustment for age, history of revascularization therapy, diabetes, smoking, alcohol consumption, body mass index, triglyceride levels, and renal function.

Conclusion: Uric acid levels are associated with the degree of leg ischemia in patients with PAD. Further interventional studies are needed to determine whether the correction of uric acid levels is effective in preventing the progression of PAD.

Assessment of Renal Function and Risk Factors for Chronic Kidney Disease in Patients With Peripheral Arterial Disease

Chronic kidney disease (CKD) and peripheral arterial disease (PAD) share common risk factors. We assessed renal function and the prevalence of CKD in patients with PAD and investigated the characteristics of the risk factors for CKD in this population. Renal function of 421 patients with PAD was evaluated. Among the participants, 194 (46.1%) patients had decreased estimated glomerular filtration rate (eGFR). The prevalence of CKD was much higher among patients with PAD. Hypertension (odds ratios [ORs] 2.156, 95% confidence interval [CI] 1.413-3.289, P < .001), serum uric acid (OR 3.794, 95% CI 2.220-6.450, P < .001), and dyslipidemia (OR 1.755, 95% CI 1.123-2.745, P = .014) were significantly associated with CKD and the independent risk factors for CKD in patients with PAD. CKD is common and has a high prevalence in a population with PAD. Patients with PAD may be considered as a high-risk population for CKD. Recognition and modification of risk factors for CKD might beneficially decrease CKD incidence and improve prognosis in patients with PAD.

Comparison of miRNA signature versus conventional biomarkers before and after off-pump coronary artery bypass graft

Circulating levels of microRNAs (miRNAs) and their expression patterns are supposed to serve as signatures for diagnosis or prognosis of cardiovascular events. The present study aimed at determining if there is any correlation between the release pattern of 2 miRNAs and the plasma levels of conventional biomarkers cardiac troponin I (cTnI), creatine kinase (CK) and uric acid (UA) in patients undergoing their first off-pump coronary artery bypass graft (OCABG). Seventy OCABG patients (69% men, aged 59.2±8.2years) were enrolled. Emergencies, re-operations, abnormal preoperative serum cTnI and combined procedures were excluded from this study. Pre-operative mean ejection fraction was 45.8±8.6%, the average number of grafts was 3±0.87/patient, and the internal mammary artery was used for all. Beside conventional clinical assays, we performed real-time quantitative PCR to analyze the circulating levels of miR-155, miR-126 and miR-499 at 1day before surgery as well as 4days after surgery. Importantly, there was no report of myocardial infarction in our patients, pre- or post-operatively. In contrast to conventional biomarkers cTnI and CK, circulating levels of miRNAs decreased significantly (P<0.01) after revascularization surgery. A significant positive correlation was seen between the cTnI and miR-499 (r∼0.53, P<0.01) and between miR-126 and UA (r∼0.5, P<0.01). Time course study of circulating miR-499, miR-126 and miR-155 in cardiac surgery clarified their advantage and correlations to the traditional biomarkers cTnI, total CK, CK-MB and UA. Our results suggest that this signature is a novel, early biomarker which indicates myocardial ischemia in cardiac surgery. It could be postulated that the application of these miRNAs may be considered for monitoring of response to pharmacological interventions aimed at reducing cardiac ischemia, especially in OCABG candidates.

Determinants of Chronic Total Occlusion in Patients With Peripheral Arterial Occlusive Disease

Chronic total occlusion (CTO) is a common finding in 40% of the patients with peripheral arterial disease (PAD). The aim of this study was to investigate the determinants of CTO in patients with PAD. The study included a total of 211 nonanemic patients with PAD. All patients were categorized according to the Fontaine classification. In lower extremity angiography cohorts, CTO− patients were designated as group 1 and CTO+ patients were designated as group 2. Patients with CTO had significantly higher red cell distribution width (RDW), neutrophil–lymphocyte ratio, uric acid, and high-sensitivity C-reactive protein compared to patients without CTO ( P ≤ .001, P = .036, P ≤ .001, and P = .015, respectively). Albumin, total bilirubin, and direct bilirubin were significantly lower in the patients with CTO compared to patients without CTO ( P = .023, P ≤ .001, and P = .049, respectively). Multivariate logistic regression analysis showed that RDW, uric acid, and total bilirubin were independent predictors of CTO in patients with PAD. We demonstrated that increased RDW and uric acid levels and lower total bilirubin values were independently associated with CTO in patients with PAD.

Longitudinal Study of Serum Uric Acid, Nutritional Status, and Mortality in Maintenance Hemodialysis Patients

BACKGROUND AND OBJECTIVES

We hypothesized that longitudinal changes in uric acid (UA) may have independent associations with changes in nutritional parameters over time and consequently, long-term survival of patients on maintenance hemodialysis.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted a retrospective, longitudinal cohort study of a clinical database containing the medical records of patients on maintenance hemodialysis receiving dialysis between June of 1999 and December of 2012 in a single center; 200 patients (130 men and 70 women) with a median age of 69.0 (interquartile range, 59.3-77.0) years old were included in the study. Dietary intake, biochemical markers of nutrition, anthropometric measurements, and UA levels were recorded at 0, 6, 12, 18, 24, 30, and 36 months followed by 15 additional months of clinical observations. The patients were followed until January 31, 2015 (median follow-up was 38.0 [interquartile range, 30.0-46.8] months).

RESULTS

In a linear mixed effects model adjusted for baseline demographics and clinical parameters, each 1.0-mg/dl longitudinal increase in UA was associated with a 13.4% slower rate of decline in geriatric nutritional risk index (GNRI) levels over 3 years of observation (95% confidence interval [95% CI], 0.11 to 0.39; P<0.001 for UA × time interaction). UA remained associated with the rate of change in GNRI, even after controlling for C-reactive protein. During the follow-up, 87 (43.5%) all-cause and 38 (19.0%) cardiovascular deaths were reported. For each 1.0-mg/dl increase in serum UA over time, the multivariate adjusted all-cause mortality hazard ratio using Cox models with the effect of time-varying risk was 0.83 (95% CI, 0.74 to 0.95; P<0.01), which continued to be significant, even after including the baseline GNRI levels in this model: 0.89 (95% CI, 0.79 to 0.98; P=0.02).

CONCLUSIONS

Longitudinal changes in serum UA seem to track with changes in nutritional status over time, and these changes are associated with survival of patients on maintenance hemodialysis. An increase in serum UA levels over time is accompanied by improvement of nutritional status and lower mortality rate.

Uric acid promotes chemokine and adhesion molecule production in vascular endothelium via nuclear factor-kappa B signaling

BACKGROUND AND AIMS

Hyperuricemia is an important risk factor for atherosclerosis, yet the potential mechanisms are not well understood. Migration and adhesion of leukocytes to endothelial cells play key roles in initiation and development of atherosclerosis. We investigated monocyte-endothelial cell interactions and potential signaling pathways under uric acid (UA)-stimulated conditions.

METHODS AND RESULTS

Primary human umbilical vein endothelial cells (HUVECs) were cultured and exposed to different concentrations of UA for various periods. Experimental hyperuricemia rat models were established. Expression of chemoattractant protein-1 (MCP-1), interleukin 8 (IL-8), vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) were evaluated. Monocyte-endothelial cell interactions were elucidated by chemotaxis and adhesion assays, and nuclear factor-kappa B (NF-κB) pathway was studied using fluorescent microscopy and electrophoretic mobility shift assay. Results showed that high concentration of UA stimulated generation of chemokines and adhesion molecules in ex vivo and in vivo experiments. Migration and adhesion of human monocytic leukemia cell line THP-1 cells to HUVECs were promoted and activated NF-κB was significantly increased. UA-induced responses were ameliorated by organic anion transporter inhibitor probenecid and NF-κB inhibitor BAY11-7082. It was also observed that human endothelial cells expressed urate transporter-1, which was not regulated by UA.

CONCLUSION

High concentration of UA exerts unfavorable effects directly on vascular endothelium via the NF-κB signaling pathway, the process of which requires intracellular uptake of UA.

Serum Uric Acid, Gender, and Low Ankle Brachial Index in Adults With High Cardiovascular Risk

Uric acid (UA) has been reported to be associated with cardiovascular disease (CVD) in caucasians. However, it is unclear whether this association remains significant in a Chinese population. The present study aimed to investigate the association between UA and low ankle brachial index (ABI), a measurement of peripheral arterial disease, in Chinese patients. A total of 6262 hospital-based patients with high CVD risk were enrolled. Low ABI was defined as ABI ≤0.9 in either side. Low ABI was detected in 1390 (22.2%) patients. Higher UA was significantly associated with higher risk of low ABI and modified by gender (P = .0045). After adjusting for age, body mass index, total cholesterol, triglyceride, low-density lipoprotein, high-density lipoprotein, fasting glucose, hypertension, and smoking, participants in the highest quartile of UA exhibited 37% (odds ratio [OR]:1.37, 95% confidence interval [CI]: 1.03-1.82) higher risk of low ABI compared to those in the lowest quartile in men, while OR (95% CI) was 1.69 (1.29-2.22) for women. However, when kidney function was further adjusted, the associations were attenuated in both men and women and were significant only in women. The results were suggestive of higher UA associating with higher risk of low ABI in women, and the association was largely driven by kidney function, especially in men.

Hyperuricemia and incident cardiovascular disease and noncardiac vascular events in patients with rheumatoid arthritis

Objective. To evaluate whether hyperuricemia is a risk factor for cardiovascular disease (CVD) in patients with rheumatoid arthritis (RA). Methods. A population-based inception cohort of patients diagnosed between 1980 and 2007 with adult-onset RA was assembled. A comparison cohort of age- and sex-matched subjects without RA (non-RA) was also assembled. All clinically obtained uric acid values were collected. CVD and noncardiac vascular events were recorded for each patient. Cox proportional hazards models were used to assess the impact of hyperuricemia on development of CVD, mortality, and noncardiac vascular disease. Results. In patients without RA, hyperuricemia was associated with heart failure (HR: 1.95; 95% CI: 1.13–3.39) and CVD (HR: 1.59; 95% CI: 0.99–2.55). In patients with RA, hyperuricemia was not significantly associated with CVD but was significantly associated with peripheral arterial events (HR: 2.52; 95% CI: 1.17–5.42). Hyperuricemia appeared to be more strongly associated with mortality among RA patients (HR: 1.96; 95% CI: 1.45–2.65) than among the non-RA subjects (HR: 1.57; 95% CI: 1.09–2.24). Conclusion. In patients with RA, hyperuricemia was a significant predictor of peripheral arterial events and mortality but not of CVD.

Serum uric acid as a clinically useful nutritional marker and predictor of outcome in maintenance hemodialysis patients

OBJECTIVE

The importance of serum uric acid (SUA) for the maintenance of a hemodialysis (MHD) population has not been well established. The aim of this study was to determine if SUA levels are associated with nutritional risk and consequently with adverse clinical outcomes in MHD patients.

METHODS

This was a 2-y prospective observational study, performed on 261 MHD outpatients (38.7% women) with a mean age of 68.6 ± 13.6 y. We measured prospective all-cause and cardiovascular (CV) hospitalization and mortality, nutritional scores (malnutrition-inflammation score [MIS) and geriatric nutritional risk index (GNRI), handgrip strength (HGS), and short-form 36 (SF36) quality-of-life (QoL) scores.

RESULTS

SUA positively correlated with laboratory nutritional markers (albumin, creatinine), body composition parameters, HGS (r = 0.26; P < 0.001) and GNRI (r = 0.34; P < 0.001). SUA negatively correlated with MIS (r = -0.33; P < 0.001) and interleukin-6 (r = -0.13; P = 0.04). Patients in the highest SUA tertile had higher total SF-36 scores (P = 0.04), higher physical functioning (P = 0.003), and role-physical (P = 0.006) SF-36 scales. For each 1 mg/dL increase in baseline SUA levels, the first hospitalization hazard ratio (HR) was 0.79 (95% confidence interval [CI], 0.68-0.91) and first CV event HR was 0.60 (95% CI, 0.44-0.82); all-cause death HR was 0.55 (95% CI, 0.43-0.72) and CV death HR was 0.55 (95% CI, 0.35-0.80). Associations between SUA and mortality risk continued to be significant after adjustments for various confounders including MIS and interleukin-6. Cubic spline survival models confirmed the linear trends.

CONCLUSIONS

In MHD patients, SUA is a good nutritional marker and associates with body composition, muscle function, inflammation, and health-related QoL, upcoming hospitalizations, as well as independently predicting all-cause and CV death risk.

The cross-sectional association between uric acid and atherosclerosis and the role of low-grade inflammation: the CODAM study

OBJECTIVES

The aims of this study were to investigate (i) associations between uric acid and prevalent cardiovascular disease (CVD), ankle-arm blood pressure index (AAIx) and carotid intima-media thickness (CIMT) in the total population and in predefined subgroups according to glucose metabolism status and (ii) the extent to which these associations are explained by low-grade inflammation.

METHODS

Cross-sectional analyses were conducted among 530 individuals [60.6% men, mean age 58.9 years (s.d. 6.9), 52.6% normal glucose metabolism (NGM)] at increased risk of CVD from the Cohort of Diabetes and Atherosclerosis Maastricht study. A low-grade inflammation score was computed by averaging the z-scores of eight inflammation markers [CRP, TNF-α, IL-6, IL-8, serum amyloid A, intercellular adhesion molecule 1 (ICAM-1), ceruloplasmin and haptoglobin].

RESULTS

After adjustment for traditional CVD risk factors, plasma uric acid (per s.d. of 81 μmol/l) was associated with CVD in individuals with NGM [odds ratio (OR) = 1.66, 95% CI 1.06, 2.58] but not with disturbed glucose metabolism (DGM) (OR = 0.81, 95% CI 0.55, 1.19, P interaction = 0.165). Uric acid was associated with CIMT in the total population (β = 0.024, 95% CI 0.007, 0.042) and slightly more strongly in individuals with NGM (β = 0.030, 95% CI 0.006, 0.054) than DGM (β = 0.018, 95% CI -0.009, 0.044, P interaction = 0.443). There was no association between uric acid and AAIx in any group (P interaction = 0.058). Uric acid was associated with low-grade inflammation in the total population (β = 0.074, 95% CI 0.013, 0.134, P interaction = 0.737). Adding low-grade inflammation to the models did not attenuate any of the associations.

CONCLUSION

The associations for uric acid with CIMT, and with CVD in NGM only, were not explained by low-grade inflammation. A difference in the strength of the associations between individuals with NGM and DGM was suggested.

Comorbidities in patients with crystal diseases and hyperuricemia

Crystal arthropathies are among the most common causes of painful inflammatory arthritis. Gout, the most common example, has been associated with cardiovascular and renal disease. In recent years, evidence for these associations and those involving other comorbidities, such as the metabolic syndrome, have emerged, and the importance of asymptomatic hyperuricemia has been established. In this review, an update on evidence, both experimental and clinical, is presented, and associations between hyperuricemia, gout, and several comorbidities are described. Causality regarding calcium pyrophosphate arthropathy and associated comorbidities is also reviewed.

Serum uric acid concentration and asymptomatic hyperuricemia with subclinical organ damage in general population

We assessed the effect of increased serum uric acid (SUA) concentration and hyperuricemia on subclinical organ damage. A cross-sectional examination of 1243 asymptomatic patients aged 55 to 84 years was conducted from September to October 2012. All participants underwent the measurements of SUA and other established cardiovascular (CV) risk factors. A morning spot urine sample was collected to detect microalbuminuria, and carotid plaque was scanned by B-mode ultrasound; the cardioankle vascular index and ankle-brachial index were obtained to evaluate arterial stiffness and peripheral artery disease (PAD), respectively. After adjustment for established CV risk factors, multiple logistic regression analyses showed that the highest quartile of SUA concentration and hyperuricemia had an independent association with PAD (respective odds ratios: 3.86 [1.26-11.83] and 2.33 [1.14-4.77]); this association maintained significantly in males but disappeared in females. Serum uric acid concentration and hyperuricemia are significantly associated with PAD in males.

Hyperuricemia as an independent predictor of vascular complications and mortality in type 2 diabetes patients: a meta-analysis

Background

Recent data have suggested that serum uric acid (SUA) level is positively associated with the development of type 2 diabetes (T2DM). Whether SUA is also independently associated with the development of vascular complications and mortality in T2DM is controversial.

Methods

A computerized literature search of MEDLINE, Embase and PubMed database was conducted and the odds ratio (OR) or hazard ratio (HR) for per 0.1mmol/l increase in SUA in each study was calculated. Cochrane’s Q and I² statistics were used to evaluate heterogeneity among studies and pooling OR and HR with 95% confidence intervals (CIs) were calculated using random-effects models and fixed-effects models. The pooled analysis was performed using Stata 10.0.

Results

Our search yielded 9 eligible articles (16 ORs and HRs) including 20,891 T2DM patients. Pooled estimates for the relationship suggested that each 0.1 mmol/l increase in SUA resulted in a 28% increase in the risk of diabetic vascular complications and a 9% increase in the risk of diabetic mortality. In stratification-analysis, the positive relationship between SUA and vascular complications remained significant irrespective of mean age, adjustment for metabolic variables and medications. However, it was inconsistent in different populations (significantly positive in the Asian but not in Australian and Italian population) and sample sizes (significantly positive in the relatively large sample size [≥1000] but non-significant in the small sample size [<1000]).

Conclusions

Results of this meta-analysis supported elevated SUA as an independent predictor of vascular complications and mortality in T2DM patients. SUA-lowering therapies might be helpful for prevention and treatment of vascular complications in this population.

Association between Serum Uric Acid Levels and Sleep Variables: Results from the National Health and Nutrition Survey 2005-2008

Sleep disordered breathing as well as high serum uric acid levels are independent risk factors for cardiovascular disease. However, studies evaluating the relationship between sleep-disordered breathing and hyperuricemia are limited. We examined the 2005-2008 National Health and Nutrition Examination survey's sleep variables and high serum uric acid among 6491 participants aged ≥20 years. The sleep variables included sleep duration, snoring, snorting, and daytime sleepiness. The main outcome was high serum uric acid level, defined as levels of serum uric acid >6.8 mg/dL in males and >6.0 mg/dL in females. We found that snoring more than 5 nights per week, daytime sleepiness, and an additive composite score of sleep variables were associated with high serum uric acid in the age- , sex-adjusted model and in a multivariable model adjusting for demographic and lifestyle/behavioral risk factors. The association was attenuated with the addition of variables related to clinical outcomes such as depression, diabetes, hypertension, and high-cholesterol levels. Our results indicate a positive relationship between sleep variables, including the presence of snoring, snorting, and daytime sleepiness, and high serum uric acid levels.

Risk factors for peripheral arterial disease among patients with chronic kidney disease

Patients with chronic kidney disease (CKD) have an increased risk for developing peripheral arterial disease (PAD). The aim of this study was to examine the cross-sectional association between novel risk factors and prevalent PAD in patients with CKD. A total of 3,758 patients with estimated glomerular filtration rates of 20 to 70 ml/min/1.73 m(2) who participated in the Chronic Renal Insufficiency Cohort (CRIC) study were included in the present analysis. PAD was defined as an ankle-brachial index <0.9 or a history of arm or leg revascularization. After adjustment for age, gender, race, cigarette smoking, physical activity, history of hypertension and diabetes, pulse pressure, high-density lipoprotein cholesterol, estimated glomerular filtration rate, and CRIC clinical sites, several novel risk factors were significantly associated with PAD. For example, odds ratios for a 1-SD higher level of risk factors were 1.18 (95% confidence interval [CI] 1.08 to 1.29) for log-transformed high-sensitivity C-reactive protein, 1.18 (95% CI 1.08 to 1.29) for white blood cell count, 1.15 (95% CI 1.05 to 1.25) for fibrinogen, 1.13 (95% CI 1.03 to 1.24) for uric acid, 1.14 (95% CI 1.02 to 1.26) for glycosylated hemoglobin, 1.11 (95% CI 1.00 to 1.23) for log-transformed homeostasis model assessment of insulin resistance, and 1.35 (95% CI 1.18 to 1.55) for cystatin C. In conclusion, these data indicate that inflammation, prothrombotic state, oxidative stress, insulin resistance, and cystatin C were associated with an increased prevalence of PAD in patients with CKD. Further studies are warranted to examine the causal effect of these risk factors on PAD in patients with CKD.

Highly sensitive determination of uric acid in the presence of major interferents using a conducting polymer film modified electrode

This paper describes the sensitive and selective determination of uric acid (UA) in the presence of important interferences, ascorbic acid (AA), dopamine (DA), tyrosine (Tyr) and methionine (Met) at physiological pH using an electropolymerized film of 3-amino-5-mercapto-1,2,4-triazole on glassy carbon (p-AMTa) electrode. The p-AMTa electrode shows an excellent electrocatalytic activity towards UA. This was understood from the observed higher oxidation current and heterogeneous rate constant (3.24×10(-5)ms(-1)) for UA when compared to bare GC electrode (4.63×10(-6)ms(-1)). The selective determination of UA in the presence of 1000-fold excess of AA was achieved using p-AMTa electrode. Further, the p-AMTa electrode was successfully used for the simultaneous and selective determination of UA in the presence of important interferences, DA, Tyr and Met. Using amperometric method, 40nM UA was detected for the first time. The current response of UA was increased linearly while increasing its concentration from 40nM to 0.1mM and a detection limit was found to be 0.52nM (S/N=3). Finally, the practical application of the present method was demonstrated by determining UA in human urine and blood serum samples.

Increased serum levels of uric acid are associated with sudomotor dysfunction in subjects with type 2 diabetes mellitus

The aim of this paper was to assess serum uric acid (SUA) levels in patients with type 2 diabetes mellitus (T2DM) with or without sudomotor dysfunction (evaluated by the Neuropad test). We included 36 T2DM patients with sudomotor dysfunction (group A: mean age 63.1 ± 2.6 years) and 40 age-, gender-, renal function- and T2DM duration-matched patients without sudomotor dysfunction (group B: mean age 62.1 ± 3.1 years). SUA was significantly higher in group A (P < 0.001). There was a significant correlation between SUA and Neuropad time to colour change in both groups (group A: r_s = 0.819, P < 0.001; group B: r_s = 0.774, P < 0.001). There was also a significant positive correlation between SUA and CRP in both groups (group A: r_s = 0.947, P < 0.001; group B: r_s = 0.848, P < 0.001). In conclusion, SUA levels were higher in T2DM patients with sudomotor dysfunction than those without this complication. The potential role of SUA in sudomotor dysfunction merits further study.

Peripheral neuropathy is associated with increased serum levels of uric acid in type 2 diabetes mellitus

We assessed serum uric acid (SUA) levels in patients with type 2 diabetes mellitus (T2DM) with or without peripheral neuropathy (diagnosed by the Neuropathy Disability score [NDS]). We enrolled 64 patients with T2DM with peripheral neuropathy (group A: 31 men, mean age 63.0 ± 2.8 years) and 66 age-, gender-, renal function- and T2DM duration-matched patients without neuropathy (group B: 32 men, mean age 62.4 ± 3.1 years). Serum uric acid was significantly higher in group A (P < .001). There was a significant correlation between SUA and NDS in both groups (group A: r(s) = .93, P < .001; group B: r( s) = .95, P < .001). C-reactive protein (CRP) was also significantly higher in group A (P < .001) and correlated significantly with SUA in both groups (group A: r(s) = .93, P < .001; group B: r(s) = .87, P < .001). Serum uric acid is increased in patients with T2DM with neuropathy versus those without. Whether SUA is involved in the pathogenesis of T2DM peripheral neuropathy remains to be established.

Association between Serum Uric Acid Levels and Diabetes Mellitus

Serum uric acid has been shown to be associated with cardiovascular disease, hypertension, and chronic kidney disease in previous studies. However, few studies have examined the association between serum uric acid and diabetes mellitus and their findings are not consistent. Therefore, we examined the association between serum uric acid levels and diabetes mellitus in participants from the third National Health and Nutrition Examination Survey (n = 18, 825, 52.5% women). Serum uric acid levels were categorized into quartiles. Diabetes mellitus was defined as fasting glucose ≥126 mg/dL, nonfasting glucose ≥200 mg/dL, or use of oral hypoglycemic medication or insulin (n = 395). In multivariable logistic regression models, we found that higher serum uric acid levels were inversely associated with diabetes mellitus after adjusting for age, sex, race/ethnicity, education, smoking, alcohol intake, body mass index, hypertension, and serum cholesterol. Compared to quartile 1 of serum uric acid, the odds ratio (95% confidence interval) of diabetes mellitus was 0.48 (0.35-0.66; P trend <0.0001). The results were consistent in subgroup analysis by gender and hypertension status. Higher serum uric acid levels were inversely associated with diabetes mellitus in a representative sample of US adults.

Uric acid and risk of myocardial infarction, stroke and congestive heart failure in 417,734 men and women in the Apolipoprotein MOrtality RISk study (AMORIS)

OBJECTIVES

Few studies have simultaneously analysed the influence of elevated serum uric acid (UA) on acute myocardial infarction (AMI), ischaemic and haemorrhagic stroke (IS, HS) and congestive heart failure (CHF) in large healthy populations. We, here, examine UA as a risk factor for AMI, stroke and CHF by age and gender in the Apolipoprotein MOrtality RISk (AMORIS) Study.

DESIGN

Prospective study (11.8 years, range 7-17) of fatal and nonfatal acute myocardial infarction, stroke and CHF through linkage with Swedish hospital discharge and mortality registers.

SETTINGS

Measurements of uric acid in 417,734 men and women from health check-ups in Stockholm area.

RESULTS

There was a gradual increase in risk of AMI, stroke and CHF by increasing UA levels. Women had a stronger relationship between UA and both AMI and IS than men. Predictions of AMI were at least as powerful in the elderly as in the young, but not so for IS. Associations were markedly attenuated when adjusted for total cholesterol, triglycerides, hospital hypertension and diabetes status. The association between UA and HS was U-shaped in both genders. CHF was more strongly related to UA than AMI and stroke and less affected by the adjustment factors.

CONCLUSIONS

Already moderate levels of UA appear to be associated with an increased incidence of AMI, stroke and CHF in middle-aged subjects without prior cardiovascular disease. These associations seem to increase gradually from lower to higher levels of UA. UA may be an important complementary indicator of cardiovascular risk in the general population.