Serum uric acid is associated with carotid plaques: the National Heart, Lung, and Blood Institute Family Heart Study

The impact of serum acid, arterial stiffness, and hypertension as a mediating factor: A cohort study

BACKGROUND

Serum uric acid (SUA) has been associated with arterial stiffness. However, previous studies were limited to contradicting cross-sectional studies. This study aimed to examine the longitudinal association between SUA and the progression of arterial stiffness and the potential mechanisms.

METHODS

Based on the Kailuan study, arterial stiffness progression was assessed by the annual growth rate of repeatedly measured brachial-ankle pulse wave velocity (baPWV). Generalized linear regression models were used to estimate the association of SUA with baseline arterial stiffness (n = 37,659) and arterial stiffness progression (n = 16,506), and Cox regressions were used to investigate the risk of incident arterial stiffness (n = 13,843). Mediation analysis was used to explore the potential mediators of the associations.

RESULTS

Per standard deviation increase in SUA was associated with an 11.89 cm/s increment (95% confidence interval [CI], 8.60-15.17) in baseline baPWV and a 2.67 cm/s/yr increment in the annual growth rate of baPWV. During the 5.77-year follow-up, there were 1953 cases of incident arterial stiffness. Participants in the highest quartile of SUA had a 39% higher risk of arterial stiffness (HR, 1.39; 95% CI, 1.21-1.60), as compared with those in the lowest quartile of SUA. Furthermore, the observed associations were more pronounced in women than in men (Pint<0.05). The pathological pathway from high SUA to arterial stiffness was mainly mediated through hypertension (mediated proportion: 24.74%).

CONCLUSIONS

Our study indicates that SUA was positively associated with the risk of arterial stiffness and its progression, especially in women. The association was mainly mediated through hypertension.

Development and Internal Validation of a Risk Prediction Model for Carotid Atherosclerosis in the Hyperuricemia Population

Purpose

The aim of this study was to identify independent risk factors for carotid atherosclerosis (CAS) in a population with hyperuricemia (HUA) and develop a CAS risk prediction model.

Patients and Methods

This retrospective study included 3579 HUA individuals who underwent health examinations, including carotid ultrasonography, at the Zhenhai Lianhua Hospital in Ningbo, China, in 2020. All participants were randomly assigned to the training and internal validation sets in a 7:3 ratio. Multivariable logistic regression analysis was used to identify independent risk factors associated with CAS. The characteristic variables were screened using the least absolute shrinkage and selection operator combined with 10-fold cross-validation, and the resulting model was visualized by a nomogram. The discriminative ability, calibration, and clinical utility of the risk model were validated using the receiver operating characteristic curve, calibration curve, and decision curve analysis.

Results

Sex, age, mean red blood cell volume, and fasting blood glucose were identified as independent risk factors for CAS in the HUA population. Age, gamma-glutamyl transpeptidase, serum creatinine, fasting blood glucose, total triiodothyronine, and direct bilirubin, were screened to construct a CAS risk prediction model. In the training and internal validation sets, the risk prediction model showed an excellent discriminative ability with the area under the curve of 0.891 and 0.901, respectively, and a high level of fit. Decision curve analysis results demonstrated that the risk prediction model could be beneficial when the threshold probabilities were 1-87% and 1-100% in the training and internal validation sets, respectively.

Conclusion

We developed and internally validated a risk prediction model for CAS in a population with HUA, thereby contributing to the CAS early identification.

Serum Urate Levels and Ultrasound Characteristics of Carotid Atherosclerosis across Obesity Phenotypes

BACKGROUND

Existing evidence suggests a close link among high levels of serum urate (SU), obesity and carotid atherosclerosis. The aim of the present study was to evaluate the interrelations between SU levels and carotid atherosclerosis in subjects with different obesity phenotypes.

METHODS

In this study, a total of 2076 subjects (mean age 48.1 ± 13.1 years; 1307 women) were recruited: 59 with general obesity, 616 with central obesity, 715 with mixed (general-central) obesity and 686 non-obese. Anthropometric measurements, vascular risk factors, blood biochemistry analysis (including SU levels), and carotid ultrasound were performed. Ultrasound assessment included evaluation of intima-media thickness (IMT) and plaque characteristics, including number, total area and type (vulnerable vs. stable) of plaques.

RESULTS

After adjustment for potential confounders, the highest levels of SU were observed in subjects with mixed obesity, followed by subjects with central obesity, general obesity and the non-obese (309.4 ± 82.2 vs. 301.2 ± 73.1 vs. 272.9 ± 61.8 vs. 234.2 ± 59.8 μmol/L, respectively; F = 149.2, post hoc p < 0.001). Similarly, subjects with mixed and central obesity presented higher values of IMT compared to subjects with general obesity and the non-obese (0.68 ± 0.16 vs. 0.67 ± 0.16 vs. 0.62 ± 0.14 vs. 0.57 ± 0.13 mm, respectively; F = 54.2, post hoc p < 0.001). No difference in number, total area and type of plaques among obesity groups were attested (all p > 0.05). Significantly higher IMT values were observed in subjects with increased SU levels compared to subjects with normal SU levels (0.70 ± 0.10 vs. 0.62 ± 0.14 mm, p = 0.02) only within the central obesity group. Increasing levels of SU were associated with a higher frequency of increased IMT only in subjects with central obesity (OR 1.033, 95% CI 1.025-1.041). Similarly, SU levels yielded a satisfactory performance in detecting subjects with increased IMT (AUC 0.65, 95% CI 0.50-0.73, subjects with carotid plaques (0.62, 95% CI 0.55-0.68) and subjects with vulnerable plaque types (0.68, 0.59-0.76) only within the central obesity group.

CONCLUSIONS

Among the studied obesity types, the association between SU levels and markers of carotid atherosclerosis was of particular significance in subjects with central obesity.

Association between Stroke Risk and Influenza Vaccination in Patients with Gout: A Nationwide Population-Based Study

The risk of stroke in patients with gout is high. The effect of vaccines in lowering the stroke risk in patients with gout remains unclear. We retrospectively analyzed 23,949 patients with gout (age ≥ 55 years) from the National Health Insurance Research Database over a 12-year period. The patients were divided into vaccinated (n = 11,649) and unvaccinated groups (n = 12,300). Overall, the vaccinated group had significantly lower risks of all stroke, hemorrhagic stroke, and ischemic stroke than the unvaccinated group (adjusted hazard ratio [aHR], 0.59 and 95% confidence interval [CI], 0.55–0.63; aHR, 0.60 and 95% CI, 0.49–0.73; and aHR, 0.60 and 95% CI, 0.55–0.65, respectively). The association appeared to be dose-dependent for both hemorrhagic and ischemic stroke (hemorrhagic stroke: aHR, 0.81 and 95% CI, 0.61–1.08; aHR, 0.80 and 95% CI, 0.62–1.02; and aHR, 0.37 and 95% CI, 0.28–0.48; ischemic stroke: aHR, 0.83 and 95% CI, 0.74–0.94; aHR, 0.73 and 95% CI, 0.65–0.81; and aHR, 0.42 and 95% CI, 0.38–0.47 for patients vaccinated 1, 2 or 3, and ≥4 times, respectively, during the follow-up period). Patients with a history of atrial fibrillation did not have a lower risk of hemorrhagic stroke even after receiving four vaccinations (aHR, 0.59; 95% CI, 0.25–1.38). Influenza vaccination was associated with a lower risk of all stroke in people with gout, and the association appeared to be dose-dependent.

Uric Acid Expression in Carotid Atherosclerotic Plaque and Serum Uric Acid Are Associated With Cerebrovascular Events

BACKGROUND

Uric acid (UA) concentration within carotid plaque and its association with cerebrovascular events have not been detected or quantified. Systemically, serum UA is a marker of inflammation and risk factor for atherosclerosis. However, its association with carotid plaque instability and stroke pathogenesis remains unclear. In patients undergoing carotid endarterectomy, we aimed to determine whether UA is present differentially in symptomatic versus asymptomatic carotid plaques and whether serum UA is associated with cerebrovascular symptoms (stroke, transient ischemic attack, or amaurosis fugax).

METHODS

Carotid atherosclerotic plaques were collected during carotid endarterectomy. The presence of UA was assessed using Gomori methenamine silver staining as well as anti-UA immunohistochemical staining and its quantity measured using an enzymatic colorimetric assay. Clinical information was obtained through a retrospective review of data.

RESULTS

UA was more commonly detected in symptomatic (n=23) compared with asymptomatic (n=9) carotid plaques by Gomori methenamine silver (20 [86.9%] versus 2 [22.2%]; P=0.001) and anti-UA immunohistochemistry (16 [69.5%] versus 1 [11.1%]; P=0.004). UA concentration was higher in symptomatic rather than asymptomatic plaques (25.1 [9.5] versus 17.9 [3.8] µg/g; P=0.021). Before carotid endarterectomy, serum UA levels were higher in symptomatic (n=341) compared with asymptomatic (n=146) patients (5.9 [interquartile range, 4.6-6.9] mg/dL versus 5.2 [interquartile range, 4.6-6.2] mg/dL; P=0.009).

CONCLUSIONS

The current study supports a potential role of UA as a potential tissue participant and a systemic biomarker in the pathogenesis of carotid atherosclerosis. UA may provide a mechanistic explanation for plaque instability and subsequent ischemic cerebrovascular events.

Increased Impact of Serum Uric Acid on Arterial Stiffness and Atherosclerosis in Females

AIMS

Serum uric acid increases with metabolic disorders; however, whether the effects of uric acid on atherosclerosis are different in females and males has not been sufficiently evaluated. Therefore, this study compared the impact of uric acid on arterial stiffness and atherosclerosis between females and males.

METHODS

We enrolled 10196 untreated middle-aged subjects (46±8 years, 3021 females and 7175 males) who underwent periodic health check-ups. Serum uric acid levels were measured and arterial stiffness and atherosclerosis were assessed by the cardio-ankle vascular index (CAVI), carotid intima-media thickness (IMT), and plaque, using ultrasound imaging.

RESULTS

Females with increased arterial stiffness (CAVI ≥ 8.0) or carotid plaques had higher uric acid than those without (P＜0.0001), but males did not. In multivariable regression analyses including overall participants, uric acid was significantly associated with the CAVI, where sex interacted with uric acid. In sex-specific analyses, uric acid was significantly associated with the CAVI, but not with carotid IMT, in both sexes. However, logistic regression analyses revealed that serum uric acid was independently associated with the presence of carotid plaques in females. The exclusion of subjects with abdominal obesity or metabolic syndrome from the analysis did not alter the results in females.

CONCLUSIONS

Serum uric acid was significantly associated with the CAVI in both sexes, but the interaction of sex was confirmed and associated with a carotid plaque only in females. These findings support the increased impact of serum uric acid on arterial stiffness and atherosclerosis in females.

Metabolic Factors Mediate the Association Between Serum Uric Acid to Serum Creatinine Ratio and Cardiovascular Disease

Background

The serum uric acid/serum creatinine ratio (SUA/SCr), which represents renal function‐normalized SUA, is associated with diverse adverse outcomes. The aim of this study was to investigate the association between SUA/SCr and cardiovascular disease (CVD), and determine whether and to what extent this association is mediated by cardiometabolic factors.

Methods and Results

This prospective study enrolled 96 378 participants from the Kailuan study without stroke and myocardial infarction at baseline (2006). Cox proportional hazard models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs). Mediation analyses were conducted to separately explore the mediating effects of cardiometabolic factors on the association between SUA/SCr and CVD. During median follow up of 11.01 years, 6315 (6.55%) individuals developed incident CVD. After adjustment for potential confounders, the highest quartile of SUA/SCr was associated with the highest risk of CVD (HR, 1.15; 95% CI, 1.07–1.23), stroke (HR, 1.16; 95% CI, 1.07–1.26), ischemic stroke (HR, 1.12; 95% CI, 1.02–1.22), and hemorrhagic stroke (HR, 1.36; 95% CI, 1.11–1.65), but not with myocardial infarction (HR, 1.07; 95% CI, 0.92–1.25). The association was consistent across different degrees of kidney function and glucose tolerance statuses. Additionally, the association between high SUA/SCr and CVD was partially mediated by triglycerides (30.74%), body mass index (BMI) (19.52%), total cholesterol (15.06%), hs‐CRP (high‐sensitivity C‐reactive protein) (13.06%), diastolic blood pressure (11.75%), and blood glucose (−16.38%).

Conclusions

SUA/SCr and CVD were positively associated. Furthermore, this association was partially mediated through blood lipids, BMI, blood pressure, hs‐CRP, and blood glucose.

Carotid Artery Pathology in Inflammatory Diseases

There is considerable evidence that patients with inflammatory conditions are at higher risk of developing cardiovascular (CV) disease including carotid artery stenosis. CV disease accounts for 35-50% of the excess mortality in patients with inflammatory diseases such as rheumatoid arthritis, with cerebrovascular disease being the second leading cause of death. We review current evidence regarding the association of inflammatory conditions and specifically carotid artery disease. Clinical epidemiological observations suggest that mechanisms other than classic risk factors may promote accelerated atherogenesis in rheumatoid and other inflammatory arthritis and carotid artery disease is increased in individuals with these conditions. Additional studies to better understand the underlying mechanisms and targeted strategies to mitigate such risk are indicated. For now, lifestyle modifications, aggressive treatment of risk factors and lipid lowering therapy in appropriate individuals is indicated.

Role of Carotid Ultrasound and Systematic Coronary Risk Evaluation Charts for the Cardiovascular Risk Stratification of Patients with Psoriatic Arthritis

OBJECTIVE

The assessment of the cardiovascular (CV) risk is recommended in patients with chronic inflammatory rheumatic diseases. The objectives of this study were to assess the CV risk profile in a cohort of patients with psoriatic arthritis (PsA), to determine the presence of subclinical cardiovascular disease by carotid ultrasound (US), and to study the association of CV disease to PsA characteristics.

METHODS

This was a cross-sectional multicentric descriptive study. The clinical CV risk was calculated with Systematic Coronary Risk Evaluation (SCORE) charts. Common carotid US was conducted to evaluate the carotid wall intima-media thickness and the presence of atheroma plaques. Patients were reclassified upon US results. Multivariate analyses were performed to identify associations of US carotid abnormalities with the classical CV risk factors and PsA characteristics.

RESULTS

The study included 176 patients with PsA. The SCORE-estimated CV risk was intermediate in 65.3% of the patients. In the US study, 32% of the patients had abnormalities, and 30.8% of the patients were upgraded and reclassified as very high risk owing to the presence of atheroma. Subclinical CV disease was associated with age and dyslipidemia but not with other risk factors. It was associated with axial disease in the subgroup with intermediate risk, and with C-reactive protein levels in patients with high risk.

CONCLUSION

Many patients with PsA have clinical estimated intermediate or high risk of a fatal CV event. A carotid US study detects subclinical vascular disease and may be useful to depict the real risk. The presence of atheroma is only partially explained by the classic CV risk factors.

The differential role of uric acid - The purpose or cause of cardiovascular diseases?

For 40 years many studies have been conducted to verify the connection between serum uric acid concentration and cardiovascular diseases, such as myocardial infarction. Unfortunately, it remains unclear which form of uric acid - prooxidant or antioxidant - could be a predictive marker of cardiovascular disease, especially in patients after myocardial infarction. It is well-known that uric acid is an organic compound and the water-soluble final product of purine catabolism, which is catalysed by xanthine oxidoreductase and excreted by kidneys. An increased concentration of UA in human plasma leads to diseases like tumours, renal disorders, atherosclerosis, hypertension, diabetes, metabolic syndrome, polycythaemia vera, haemolytic anaemias, ischemia, oxidative stress, and rare genetic disorders connected with UA degradation. Epidemiological studies have shown that UA might be a marker of oxidative stress, progression of inflammation, or renal disease. A fortiori, it is possible that could also be a predictor for short/long-term survival of patients with CVD. Evidence provided by multiple studies is controversial and mutually exclusive. Among 71 studies the most of them found an independent association between SUA and CVD risk. Some of those studies confirm that CVD risk is higher in women who had elevated SUA levels. On the other hand, many studies reached the opposite conclusion and did not find any relationship between SUA and CVD mortality and morbidity.

Association between serum level of urate and subclinical atherosclerosis: results from the SCAPIS Pilot

BACKGROUND

Hyperuricemia is closely associated with cardiovascular disease (CVD). However, it has not been definitively established whether this association is independent of traditional cardiovascular risk factors (CVRFs) and whether it is gender-dependent. The aim of this study was to investigate in a population-based cohort (age range, 50-64 years) stratified by sex the association between the serum urate (SU) concentration and subclinical atherosclerosis, as reflected in the coronary artery calcification (CAC) score, common carotid intima-media thickness (CIMT), and carotid plaque score.

METHODS

The study involved participants in the Swedish CArdioPulmonary bioImage Study (SCAPIS) Pilot cohort (N = 1040; 48.8% males). This pilot cohort is part of the large population-based SCAPIS with 30,000 participants in the age range of 50-64 years, aimed at improving risk prediction for CVD. Subjects with a self-reported previous history of CVD (N = 68) or gout (N = 3) were excluded. The CAC score was assessed with the Agatston method using computed tomography. CIMT and carotid plaques were quantified by ultrasound. The associations between the SU quartiles and different levels of CAC, CIMT, and carotid plaques were assessed by multivariable logistic regression.

RESULTS

Age, BMI, education level, smoking, physical activity, hs-CRP, hypertension, and dyslipidemia showed no differences between males and females, while CAC (score > 0) and diabetes were both twice as common in men than in women (58% vs 26% and 8% vs 4%, respectively). Higher SU quartiles were in both sexes associated with BMI, hs-CRP, and the prevalence of hypertension, and in women, they were also associated with the prevalence of dyslipidemia. The three upper quartiles of SU (>308μmol/L) were linked to higher CAC scores in men, when adjusting for CVRFs, but not in women. CIMT and carotid plaques showed no correlation to SU in either sex.

CONCLUSIONS

Higher levels of SU are associated with the presence of CAC in men but not in women, whereas SU is not associated with CIMT or carotid plaques in either men or women. This implies that the biological effects of SU differ in men and women or that SU has varying effects on different vascular beds or during the different stages of the atherosclerotic process.

Study of association of serum uric acid with albuminuria and carotid atherosclerosis in type 2 diabetes mellitus patients

Introduction:

Type 2 diabetes mellitus is a heterogeneous group of metabolic disorders of disturbance of carbohydrate, fat, and protein metabolism causing macrovascular (like coronary artery disease) and microvascular (kidney damage) complications. Microalbuminuria is the first manifestation of injury to glomerular filtration barrier and carotid intima-media thickness (IMT) of common carotid artery serves as an excellent marker for early lesion of atherosclerosis.

Method:

A cross-sectional observational study was carried out over a period of 1.5 years in PGIMER, DR. RML Hospital, New Delhi. Patients with type 2 diabetes mellitus, aged between 35 and 60 years, were investigated for uric acid (UA), urine albumin levels, and common carotid IMT during this period. Patients on drugs that affect serum UA level, patients with acute illness, patients with serum creatinine >1.5 mg/dL, or with coronary artery disease were excluded from study.

Result:

Prevalence of hyperuricemia was found to be high (46%) in type 2 diabetic patients. It was also higher in females (73.7%) than males (25.8%). There was positive correlation between serum UA concentrations with logarithm of urine albumin excretion (P < 0.023) and carotid intima-media thickness (IMT) (P < 0.027). Plaque index also showed a positive correlation with UA (P < 0.019). However, there was no positive correlation with UA and other variable such as age, duration of diabetes, systolic blood pressure, diastolic blood pressure, HbA1c, lipid profiles, urea, and creatinine.

Conclusion:

Serum UA concentration thus serves as an early marker of renal dysfunction and cardiovascular diseases in type 2 diabetic patients.

Modifiable risk factors for carotid atherosclerosis: a meta-analysis and systematic review

Background

Carotid atherosclerosis is a major cause of stroke, but the conclusion about risk factors for carotid atherosclerosis is still controversial. The aim of our present meta-analysis and systematic review was to explore the modifiable risk factors for carotid atherosclerosis.

Methods

We searched PubMed from January 1962 to October 2018 to include longitudinal and cross-sectional studies. The results were pooled using random effects model. Heterogeneity was measured by I² statistic and publication bias was assessed by funnel plots.

Results

A total of 14,700 articles were screened, of which 76 with 27 factors were eligible. Our meta-analysis of cross-sectional studies indicated nine factors (hyperlipidemia, hyperhomocysteinemia, hypertension, hyperuricemia, smoking, metabolic syndrome, hypertriglyceridemia, diabetes, and higher low density lipoprotein) were significantly associated with the presence of carotid plaque, among which four (hyperlipidemia, hyperhomocysteinemia, hypertension, and hyperuricemia) could elevate the risk of atherosclerosis by at least 50%; and one factor (hypertension) was associated with increased carotid intima-media thickness. In the systematic review, another five factors [negative emotion, socioeconomic strain, alcohol, air pollution, and obstructive sleep apnea syndrome (OSAS)] were also related to the presence of atherosclerosis. The cross-sectional associations with most of the above 14 factors were further confirmed by longitudinal studies. Among them, the managements of 4 factors (hypertension, hyperlipidemia, diabetes and OSAS) were indicated to prevent carotid atherosclerosis by cohort studies.

Conclusions

Effective interventions targeting pre-existing disease, negative emotion, lifestyle and diet may reduce the risk of carotid atherosclerosis. Further good-quality prospective studies are needed to confirm these findings.

Uric acid: from a biological advantage to a potential danger. A focus on cardiovascular effects

Non-communicable diseases represent nowadays the most common cause of death worldwide, having largely overcome infectious diseases. Among them, cardiovascular diseases constitute the majority. Given these premise, great efforts have been made by scientific societies to emphasize the fundamental role of cardiovascular prevention and risk factors control. In addition to classical cardiovascular risk factors such as smoking, arterial hypertension, hypercholesterolemia and male gender, new risk factors are emerging from international literature. Among them, uric acid is the protagonist. Several evidences show a direct role of hyperuricemia in the determinism of metabolic and vascular disorders. From the other hand, some researchers have demonstrated that uric acid is only a marker of cardiovascular damage and not a risk factor for its development. Aim of this review is to evaluate the scientific evidences on the role of uric acid in cardiovascular diseases in order to shed light on this confusing topic.

Uric acid and cardiovascular disease

Uric acid (UA) is an end product of purine metabolism in humans and great apes. UA acts as an antioxidant and it accounts for 50% of the total antioxidant capacity of biological fluids in humans. When present in cytoplasm of the cells or in acidic/hydrophobic milieu in atherosclerotic plaques, UA converts into a pro-oxidant agent and promotes oxidative stress and through this mechanism participates in the pathophysiology of human disease including cardiovascular disease (CVD). Most epidemiological studies but not all of them suggested the existence of an association between elevated serum UA level and CVD, including coronary heart disease (CHD), stroke, congestive heart failure, arterial hypertension and atrial fibrillation as well as an increased risk for mortality due to CVD in general population and subjects with confirmed CHD. Evidence available also suggests an association between elevated UA and traditional cardiovascular risk factors, metabolic syndrome, insulin resistance, obesity, non-alcoholic fatty liver disease and chronic kidney disease. Experimental and clinical studies have evidenced several mechanisms through which elevated UA level exerts deleterious effects on cardiovascular health including increased oxidative stress, reduced availability of nitric oxide and endothelial dysfunction, promotion of local and systemic inflammation, vasoconstriction and proliferation of vascular smooth muscle cells, insulin resistance and metabolic dysregulation. Although the causality in the relationship between UA and CVD remains unproven, UA may be pathogenic and participate in the pathophysiology of CVD by serving as a bridging mechanism mediating (enabling) or potentiating the deleterious effects of cardiovascular risk factors on vascular tissue and myocardium.

The modality of dialysis does not influence atheromatous vascular disease progression or cardiovascular outcomes in dialysis patients without previous cardiovascular disease

BACKGROUND

There is limited and inconclusive information regarding the influence of the modality of renal replacement therapy on the atherosclerotic burden of patients on dialysis. The aim of this study was to compare the prevalence of asymptomatic atheromatous carotid disease, as also its rate of progression and cardiovascular outcomes, in two matched populations of patients treated with hemodialysis (HD) and peritoneal dialysis (PD).

METHODS

Following a prospective, observational and multicenter design, we compared 237 PD and 237 HD patients without previous cardiovascular disease, included in the NEFRONA study, and matched for age, sex, diabetes and time on dialysis. Carotid ultrasound study was performed at baseline and after two years of follow-up in 6 carotid territories. Atheromatous vascular disease (AVD) progression was defined as any increase in the number of territories with plaques after 2 years. Fatal and non fatal cardiovascular events were also recorded during 36-month of follow-up.

MAIN RESULTS

At baseline, PD patients presented a worse general cardiovascular risk profile than HD patients. On the contrary, some markers of prevalent atherosclerotic disease (common carotid intima-media thickness and ankle-brachial index) were more favorable in PD patients. During follow-up, we observed no differences either in the rate of progression of atheromatous vascular disease (OR 1.78, 95% CI 0.80-4.06, p = 0.161) or in the incidence of cardiovascular events (OR 1.51, 95% CI 0.85-2.66, p = 0.159), according to the modality of dialysis.

CONCLUSION

Dialysis modality did not impact on atherosclerotic carotid disease progression or cardiovascular outcomes, in two groups of patients treated with PD or HD.

Is gout a risk equivalent to diabetes for stroke and myocardial infarction? A retrospective claims database study

Background

Gout is a risk factor for cardiovascular disease, but associations with specific cardiovascular outcomes, myocardial infarction (MI), and stroke are unclear. Our objective in the present study was to assess whether gout is as strong a risk factor as diabetes mellitus (DM) for incident MI and incident stroke.

Methods

In this retrospective study, we used U.S. claims data from 2007 to 2010 that included a mix of private and public health plans. Four mutually exclusive cohorts were identified: (1) DM only, (2) gout only, (3) gout and DM, and (4) neither gout nor DM. Outcomes were acute MI or stroke with hospitalization. We compared the age- and sex-specific rates of incident MI and stroke across the four cohorts and assessed multivariable-adjusted HRs.

Results

In this study, 232,592 patients had DM, 71,755 had gout, 23,261 had both, and 1,010,893 had neither. The incidence of acute MI was lowest in patients with neither gout nor DM, followed by patients with gout alone, DM alone, and both. Among men >80 years of age, the respective rates/1000 person-years were 14.6, 25.4, 27.7, and 37.4. Similar trends were noted for stroke and in women. Compared with DM only, gout was associated with a significantly lower adjusted HR of incident MI (HR 0.81, 95% CI 0.76–0.87) but a similar risk of stroke (HR 1.02, 95% CI 0.95–1.10). Compared with patients with DM only, patients with both gout and DM had higher HRs for incident MI and stroke (respectively, HR 1.35, 95% CI 1.25–1.47; HR 1.42, 95% CI 1.29–1.56).

Conclusions

Gout is a risk equivalent to DM for incident stroke but not for incident MI. Having both gout and DM confers incremental risk compared with DM alone for both incident MI and stroke.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-017-1427-5) contains supplementary material, which is available to authorized users.

Association between serum uric acid level and renal arteriolar hyalinization in individuals without chronic kidney disease

BACKGROUND AND AIMS

Recent studies have reported an association between serum uric acid (SUA) and renal arteriolar changes in patients with chronic kidney disease (CKD). However, the association in individuals without CKD remains unclear. In this study, we investigated the relationship between SUA and renal arteriolar lesions in individuals without CKD from our living kidney donor cohort.

METHODS

Between January 2006 and May 2016, 393 living kidney donors underwent "time-zero" biopsy at Kyushu University Hospital. Patients were divided into sex-specific quartiles of SUA before donation: Q1, Q2, Q3, and Q4 (male: <5.2,5.2-5.8,5.9-6.4, and ≥6.5 mg/dL, female: <3.8,3.8-4.3,4.4-5.0, and ≥5.1 mg/dL). Renal arteriolar hyalinization and wall thickening were assessed using a semiquantitative grading system. Predictive performance was compared between models with and without SUA by calculating the net reclassification improvement (NRI).

RESULTS

In total, 158 (40.2%) patients had arteriolar hyalinization, and 148 (37.6%) had wall thickening. High SUA was significantly associated with arteriolar hyalinization in multivariable logistic analysis (odds ratio [OR] per 1-mg/dL increase in SUA, 1.24; 95% confidence interval [CI], 1.00-1.53; p = 0.048. OR for Q4 vs. Q2, 2.22; 95% CI, 1.17-4.21; p = 0.01). We found no association between SUA and wall thickening. When SUA was incorporated into a predictive model with conventional atherosclerotic factors, the NRI was 0.21 (p = 0.04).

CONCLUSIONS

High SUA was an independent risk factor for arteriolar hyalinization in individuals without CKD. SUA provided additional predictive value beyond conventional atherosclerotic factors in predicting arteriolar hyalinization.

Prevalence of calcified carotid artery atheromas on panoramic images of older men with gout: a descriptive retrospective study

OBJECTIVES

Given the enhanced risk of ischaemic stroke resulting from the direct effects of hyperuricaemia on vascular plaque formation seen among older males with gout, we sought to determine the prevalence of calcified carotid artery atheromas (CCAAs) on their panoramic images (PIs).

METHODS

Medical record librarians identified all male patients over 45 years, who had a diagnosis of gout and a PI incidentally obtained between 2000 and 2015. The prevalence rate of CCAA on technically appropriate images was determined, as were these patients' atherogenic risk profiles including: age, body mass index, hypertension and dyslipidaemia. Comparisons of atherogenic risk factors were made between this cohort and those without CCAA.

RESULTS

Of the 531 patients with gout, 163 patients were adjudicated to be CCAA+ (the panoramic image demonstrates a calcified carotid artery atheroma). Logistic regression analysis demonstrated that a comorbid diagnosis of diabetes mellitus or dyslipidaemia, or advancing age was determinant in differentiating patients who were CCAA+ vs those who were CCAA- (the panoramic image does not demonstrate a calcified carotid artery atheroma).

CONCLUSIONS

CCAAs often herald an ischaemic stroke and may be seen on the PIs of patients with gout, especially those with increased age, dyslipidaemia or diabetes. Thus, dentists must be uniquely vigilant in detecting these lesions when evaluating the images of all patients with gout, especially those with additional positive risk factors.

Sex-specific Association Between Uric Acid and Outcomes After Acute Ischemic Stroke: A Prospective Study from CATIS Trial

The relationship between serum uric acid (UA) and outcomes after acute ischemic stroke remains debatable in human studies, and the sex effect on this association has yet to be explored. Here, we investigated these associations in a prospective study from the China Antihypertensive Trial in Acute Ischemic Stroke. Baseline UA levels were measured in 3284 acute ischemic stroke patients. Primary outcome was defined as a combination of death and major disability (modified Rankin Scale score ≥3) at 3 months. UA levels were significantly higher in men than women (310.6 ± 96.1 vs 257.5 ± 89.9 μmol/L, P < 0.001). The association between serum UA and the primary outcome was appreciably modified by sex (P-interaction = 0.007). After multivariate adjustment, a high serum UA was associated with a decreased risk of primary outcome in men [odds ratio (OR), 0.63; 95% confidence interval (CI), 0.44-0.91; P-trend = 0.01] but not in women (OR, 1.29; 95% CI, 0.83-2.01; P-trend = 0.15), when two extreme quartiles were compared. Subgroup and sensitivity analyses further confirmed these sex-specific findings. Our study indicated that there was a sex-specific association between serum UA and prognosis of acute ischemic stroke. Elevated serum UA was positively associated with better prognosis in men, but not in women.

Evaluation of cardiovascular risk in stages of gout by a complex multimodal ultrasonography

The aim of our work was to assess ultrasound features of cardiovascular (CV) risk in stages of gout. Cross-sectional complex multimodal ultrasound study of 169 age-matched patients, with similar distribution of arterial hypertension, diabetes mellitus, obesity and chronic renal failure, was divided into four groups: 41 with asymptomatic hyperuricemia, 52 gout without tophi, 42 gouty tophi and 34 controls with osteoarthritis. Parameters independently associated with CV risk were measured: renal resistive index (RRI), left ventricular mass index (LVMi), mitral annulus early diastolic velocity (e'), intima-media thickness (IMT) and common carotid artery resistive index (CCARI). Multivariate analyses were performed to evaluate the impact of gout stages and CV risk factors on ultrasound alterations. Gouty tophi increased the risk of having IMT >0.90 mm with an OR 11.51 (95 % CI 2.32-57.21, p = 0.003), gout without tophi raised the risk with an OR 6.25 (95 % CI 1.37-28.44, p = 0.018), while asymptomatic hyperuricemia had no effect on IMT. The category of CCARI >0.70 was influenced by tophi with an OR 11.18 (95 % CI 2.61-47.83, p = 0.001) and by arterial hypertension with an OR 3.22 (95 % CI 1.11-9.36, p = 0.032). Neither asymptomatic hyperuricemia nor gout without tophi modified the development of abnormally high CCARI. Gout stages had no impact on LVMi, e' and RRI. Tophi are related to worsened ultrasonographic parameters evaluating target organs in gout, relative to earlier stages of the disease. They create a strong risk of carotid arteries' changes even beyond arterial hypertension.

Losartan alleviates hyperuricemia-induced atherosclerosis in a rabbit model

OBJECTIVE

To investigate the mechanisms underlying the therapeutic effects of losartan on hyperuricemia-induced aortic atherosclerosis, in an experimental rabbit model.

METHODS

Male rabbits (n = 48) were divided into control, hyperuricemia (HU), hypercholesterolemia + hyperuricemia (HC + HU) and high-purine with 30-mg/kg/d losartan (HU + losartan) groups. Serum uric acid (UA) and plasma renin and angiotensin II activities were determined. Aortic tissue specimens were analyzed for histological changes and proliferating cell nuclear antigen (PCNA). Liver tissues were sampled for quantitative analyses of liver low-density lipoprotein receptor (LDLR) mRNA and protein via reverse transcription polymerase chain reaction and western blotting.

RESULTS

After 12 weeks, serum UA and plasma renin and plasma angiotensin II activities were enhanced in the HU and HU + HC groups (P < 0.001) compared to the control, whereas in the HU + losartan group plasma renin activity was not different and serum UA concentrations as well as plasma angiotensin II activity were moderately enhanced (P < 0.05). Smooth muscle cell (SMC) PCNA expression increased strongly in the HU and HU + HC groups (P < 0.001), but was less pronounced in the HU + losartan group. In contrast, transcription and expression of LDLR mRNA and protein were significantly higher in the control and HU + losartan groups compared to the HU and HU + HC groups. Both the HU and HU + HC groups had elevated intima thickness and intima areas compared to the control and HU + losartan groups.

CONCLUSIONS

Losartan can alleviate experimental atherosclerosis induced by hyperuricemia.

Decreased urine uric acid excretion is associated with diabetic retinopathy but not with lower limb atherosclerosis in hospitalized patients with type 2 diabetes

OBJECTIVE

To explore the associations between urine uric acid excretion (UUAE) and diabetic retinopathy (DR)/lower limb atherosclerotic lesions in hospitalized Chinese patients with type 2 diabetes.

METHODS

This cross-sectional study was conducted in 2529 hospitalized Chinese patients with type 2 diabetes. UUAE was determined enzymatically using a single 24-h urine collection. The subjects were stratified into quartile based on UUAE levels. DR was determined by digital fundus photography. Lower limb atherosclerotic lesions were assessed by Doppler ultrasound. Both DR and lower limb atherosclerosis were compared among the UUAE quartile groups, respectively.

RESULTS

There was a significant decrease in the prevalence of DR in patients across the UUAE quartiles after adjustment for sex, age and diabetic duration (35.0%, 30.7%, 26.1%, and 21.5%, respectively, p = 0.000001 for trend). A fully adjusted multiple logistic regression analyses revealed that UUAE quartiles were markedly inversely associated with the presence of DR (p = 0.030). The prevalence of lower limb plaque (73.9% vs. 62.6%, p = 0.000044) and stenosis (16.3% vs. 9.7%, p = 0.000015) was markedly higher in the diabetics with DR than in those without DR. However, there was no statistical association between the UUAE and lower limb atherosclerotic lesions in type 2 diabetes.

CONCLUSIONS

Decreased UUAE was an independent risk factor for DR but not for lower limb atherosclerosis in hospitalized Chinese patients with type 2 diabetes. In selected populations, such as those with type 2 diabetes, the role of uric acid in atherosclerosis may be result from other concomitantly atherosclerotic risk factors, such as DR.

Decreased urine uric acid excretion is an independent risk factor for chronic kidney disease but not for carotid atherosclerosis in hospital-based patients with type 2 diabetes: a cross-sectional study

Background

The associations between urine uric acid excretion (UUAE) and chronic kidney disease (CKD)/atherosclerosis have not been investigated. Our aims were to investigate the relationships between UUAE and CKD and carotid atherosclerotic lesions in hospitalized Chinese patients with type 2 diabetes.

Methods

This was a cross-sectional study that was conducted with 2627 Chinese inpatients with type 2 diabetes. UUAE was determined enzymatically using a single 24-h urine collection. The subjects were stratified into quartiles according to their UUAE levels. Carotid atherosclerotic lesions, including carotid intima-media thickness (CIMT), plaque and stenosis, were assessed by Doppler ultrasound. Both CKD and carotid atherosclerotic lesions were compared between the UUAE quartile groups.

Results

After adjustment for confounding factors, there was a significant decrease in the prevalence of CKD in the patients with type 2 diabetes across the UUAE quartiles (16.9%, 8.5%, 5.9%, and 4.9%; p < 0.001). Multiple logistic regression analyses revealed that the UUAE quartiles were significantly and inversely associated with the presence of CKD (p < 0.001). Compared with the diabetics in the highest UUAE quartile, those in the lowest quartile exhibited a nearly 4.2-fold increase in the risk of CKD (95% CI: 2.272-7.568; p < 0.001). The CIMT value (0.91 ± 0.22 mm for the diabetics with CKD and 0.82 ± 0.20 mm for the diabetics without CKD, p = 0.001) and the prevalence of carotid plaques (62.1% for the diabetics with CKD and 41.8% for the diabetics without CKD, p = 0.025) were significantly higher in the diabetics with CKD than in those without CKD. However, there was no obvious difference in carotid atherosclerotic lesions across the UUAE quartiles after controlling for the confounding factors.

Conclusions

Decreased UUAE was closely associated with the presence of CKD but not with carotid atherosclerotic lesions in hospitalized Chinese patients with type 2 diabetes. Our results suggest that UUAE is an independent risk factor for CKD in type 2 diabetes. In selected populations, such as patient with type 2 diabetes, the role of uric acid in atherosclerosis might be the result of other concomitant atherosclerotic risk factors, such as CKD.

Serum uric acid and subsequent cognitive performance in patients with pre-existing cardiovascular disease

High serum uric acid (UA) levels are associated with numerous vascular risk factors, and vascular disease, that predispose patients to cognitive impairment, yet UA is also a major natural antioxidant and higher levels have been linked to slower progression of several neurodegenerative disease. In-order to test the association between UA and subsequent cognitive performance among patients that carry a high vascular burden, UA levels were determined by calorimetric enzymatic tests in a sub-cohort of patients with chronic cardiovascular disease who previously participating in a secondary prevention trial. After an average of 9.8±1.7 years, we assessed cognitive performance (Neurotrax Computerized Cognitive Battery) as well as cerebrovascular reactivity (CVR) and common carotid intima-media thickness (IMT). Among 446 men (mean age 62.3±6.4 yrs) mean UA levels were 5.8±1.1 mg/dL. Adjusted linear regression models revealed that low UA levels (bottom quintile) were associated with poorer cognitive performance. Adjusted differences between the bottom quintile and grouped top UA quintiles were (B coefficient±SE) −4.23±1.28 for global cognitive scores (p = 0.001), −4.69±1.81 for memory scores (p = 0.010), −3.32±1.43 for executive scores (p = 0.020) and −3.43±1.97 for visual spatial scores (p = 0.082). Significant difference was also found for attention scores (p = 0.015). Additional adjustment for impaired CVR and high common carotid IMT slightly attenuated the relationship. Stronger UA effect on cognitive performance was found for older (age>65) patients with significant age interaction for global cognitive score (p = 0.016) and for executive (p = 0.018) and attention domains (p<0.001). In conclusion, we demonstrate that low UA levels in patients with preexisting cardiovascular disease are associated with poorer cognitive function a decade later. These findings lend support to the hypothesis that oxidative stress may be involved in the pathogenesis of age-associated cognitive impairment.

Association of hyperuricemia with conventional cardiovascular risk factors in elderly patients

The relationship between serum uric acid (UA) and cardiovascular risk profile was investigated in 557 outpatients (415 women) aged 60 years and older. Patients were grouped according to a UA cutoff level of 5.5 mg/dL. Prevalence of obesity, hypertension, and impaired glucose metabolism was increased in women with higher UA, who had higher body mass index (37.7±6.9 vs 33.1±5.9 kg/m(2) , P<.001), waist circumference, and serum glucose and triglyceride concentrations than women with lower UA levels. Conversely, men with higher UA levels showed lower high-density lipoprotein cholesterol and higher left ventricular mass than men with lower UA levels. Estimated glomerular filtration rate was reduced in patients with high UA levels of both sexes (65±17 vs 72±16 mL/min/1.73 m(2) , P<.001, for women; 70±16 vs 76±15 mL/min/1.73 m(2) , P<.03, for men). Grouping patients by sex-specific median UA concentrations produced similar results. These data indicate that, even in the elderly, UA clusters in a sex-specific fashion with features of metabolic syndrome and signs of target organ damage.

Association of uric acid and carotid artery disease in patients with ischemic stroke

BACKGROUND AND PURPOSE

Some previous studies reported an independent association between uric acid and coronary artery disease, while little is known on the association among uric acid and carotid artery disease (CAD). To address this issue, we investigated the association between CAD and higher uric acid level because of the well-known importance of the carotid artery pathologies for ischemic stroke.

METHODS

Between 2009 and 2012, we conducted a study among 406 consecutive first-ever ischemic stroke patients to assess the relationship between uric acid and carotid artery. A mean intima-media thickness IMT was calculated for the wall of the left and right common carotid arteries (CCA) and IMT of the bifurcation of the carotid arteries. CAD was assessed by neuroimaging techniques in patients with carotid artery stenosis more than 50%. Logistic regression models were used to determine the relation among pathological changes of the carotid artery and higher uric acid level.

RESULTS

In patients with hyperuricemia, the frequency of age (>60 years), hypertriglyceridemia, higher apo B, renal failure were significantly higher than those with normal uric acid level. CAD was more frequent in patients with hyperuricemia than those with normal uric acid level (OR, 1.8, 95% CI, 1.1-3.1; P = 0.01). In patients with higher uric acid level, the mean of the IMT of the CCA and of the bifurcation of the carotid artery were higher than those with normal uric acid level (P = 0.001 for each). Covariance matrix analysis displayed a strong correlation between CAD and age (>60 years) (P < 0.05), sex (P < 0.01), hyperuricemia (P < 0.01), hypertension (P < 0.05), and hypercholesterolemia (P < 0.05). In the models of regression analysis, a strong association was found among patients with CAD and sex, renal failure, hyperuricemia, number of plaques, and size of plaques.

CONCLUSION

Our study demonstrated that higher uric acid level is strongly associated with CAD. Elevated uric acid might be injurious for large cerebral arteries with some probable confounding risk factors. Further prospective large clinical trials will determine whether lowering uric acid level reduces the frequency of CAD and ischemic stroke.

Serum uric acid is associated with coronary artery calcification

Uric acid (UA) is associated with atherosclerosis, and coronary artery calcium (CAC) is a marker of atherosclerosis. The authors studied the association between UA and CAC. A total of 663 asymptomatic patients (564 men; mean age, 55±7 years) were evaluated for the presence of CAC. The study population was divided into three tertiles according to their UA levels, and the prevalence of CAC was compared between the tertiles. CAC was detected in 349 (53%) patients. Levels of UA were significantly higher in those with CAC than in those without CAC (5.6+1.2 vs 5.3+1.3; P=.003). The odds ratio for the presence of CAC in the highest vs lowest UA tertile was 1.72 (95% confidence interval, 1.17-2.51). The highest UA tertile remained associated with the presence of CAC after adjustment for known cardiovascular risk factors. The results show that high serum UA levels are associated with the presence of CAC.

The role of the inflammasome in cardiovascular diseases

Inflammasome is a very important signaling platform sensing a variety of triggers of the innate immune system. Inflammasome promotes the production of important pro-inflammatory cytokines such as IL-1β and IL-18. Tight control of inflammasome activity is, therefore, essential and occurs at multiple levels. The activation of inflammasome pathways is linked to the pathogenesis of various prevalent disorders including cardiovascular disease such as atherosclerosis, ischemic injury, cardiomyopathy, and Kawasaki disease. The study of the inflammasome in the cardiovascular system has led to the identification of important triggers and endogenous modulators, and to the exploration of new treatment strategies based on the inhibition of inflammasome activation or its end products, i.e., IL-1β and IL-18. In summary, the discovery of the inflammasome has greatly advanced our understanding of how the innate immune system interferes with cardiovascular disease development and progression, and targeting inflammasome provides new avenues for the treatment and management of cardiovascular diseases.

Association between serum uric acid levels and cardiovascular disease in middle-aged and elderly Chinese individuals

BACKGROUND

A link between uric acid (UA) levels and cardiovascular diseases has been previously reported. However, its importance as a risk factor is still controversial. This study sought to determine whether elevated serum uric acid levels are associated with cardiovascular disease (CVD) in middle-aged and elderly Chinese individuals.

METHODS

We conducted a population-based cross-sectional study in Shanghai, with a total of 8510 participants aged ≥40 years. The CVD included diagnosed coronary heart disease (CHD) and stroke. MetS was defined according to the updated National Cholesterol Education Program Adult Treatment Panel III criteria for Asian Americans.

RESULTS

Uric acid levels were positively associated with BMI, waist circumference, triglycerides, systolic blood pressure, diastolic blood pressure, glycohemoglobin, fasting plasma glucose, postprandial 2-hour plasma glucose (all P < 0.05), and negatively associated with HDL-cholesterol (P < 0.001). The prevalence of CVD significantly increased with increasing quartiles of UA in those without MetS group (p trend < 0.001), but not necessarily increased in those with MetS. After adjustment for metabolic syndrome and other cardiovascular risk factors, multivariate logistic regression analysis showed that odds ratios (OR) for CHD, stroke, and CVD in those in the fourth quartiles were 2.34 (95% confidence interval [CI] 1.73 to 3.45), 2.18 (95% CI 1.86 to 3.28), and 2.16 (95% CI 1.80 to 3.29), respectively, compared with those in the first quartile of UA.

CONCLUSIONS

Elevated serum uric acid level was associated with CVD, independent of conventional cardiovascular disease risk factors and metabolic syndrome.

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.

Usefulness of preprocedural serum uric acid level to predict restenosis of bare metal stents

Serum uric acid (SUA) level is known as a significant predictor for cardiovascular diseases, partly through increased inflammatory response and smooth muscle cell proliferation. Inflammation and smooth muscle cells play a crucial role in the pathogenesis of in-stent restenosis (ISR). However, the relation between SUA and ISR has not been studied. The aim of the present study was to investigate the predictive value of preprocedural SUA on the development of ISR in patients who undergo coronary bare-metal stent implantation. Clinical, biochemical, and angiographic data from 708 consecutive patients (mean age 60.3 ± 9.3 years, 71% men) who had undergone bare-metal stent implantation and additional control coronary angiography for stable or unstable angina pectoris were analyzed. Patients were divided into tertiles on the basis of preprocedural SUA levels. Stent restenosis was observed in 54 patients (23%) in the lowest tertile, in 79 (34%) in the middle tertile, and in 109 (46%) in the highest tertile (p <0.001). Using multiple logistic regression analysis, diabetes mellitus, smoking, high-density lipoprotein cholesterol, stent length, C-reactive protein level, and preprocedural SUA level emerged as independent predictors of ISR. On receiver-operating characteristics curve analysis, SUA level >5.5 mg/dl had 75% sensitivity and 71% specificity (area under the curve 0.784, p <0.001) in predicting ISR. In conclusion, higher preprocedural SUA is a powerful and independent predictor of bare-metal stent restenosis in patients with stable and unstable angina pectoris.

Longitudinal association between serum urate and subclinical atherosclerosis: the Coronary Artery Risk Development in Young Adults (CARDIA) study

OBJECTIVE

The aim of the present study was to determine whether serum urate (sUA) concentration is positively associated with subclinical atherosclerosis, independent of body mass index (BMI), amongst generally healthy adults.

DESIGN AND SETTING

The CARDIA study followed 5115 Black and White individuals aged 18-30 years in 1985-1986 (year 0). Subclinical atherosclerosis comprised coronary artery calcified plaque (CAC; years 15, 20 and 25), and maximum common carotid intima-media thickness (IMT; year 20). sUA (years 0, 10, 15 and 20) was modelled as gender-specific quartiles that were pooled. Discrete-time hazard regressions and generalized linear regressions were used for analyses.

RESULTS

Mean sUA concentration was lower in women than in men and increased with age. Adjusting for demographic and lifestyle factors, the highest versus lowest quartile of sUA at year 0 was associated with a 44% [95% confidence interval (CI) 20%, 73%] greater risk of CAC progression from years 15 to 25 (Ptrend  < 0.001), which was attenuated by adjustment for BMI at year 0 (Ptrend  = 0.45). A stronger association was found between sUA at year 15 and CAC progression at year 20 or 25 (hazard ratio 2.07, 95% CI 1.66, 2.58 for the highest versus lowest sUA quartile Ptrend  < 0.001), which was attenuated, but remained significant with additional adjustment for BMI at year 15 (Ptrend  = 0.01). A greater increment in sUA concentration from year 0 to year 15, independent of change in BMI, was related to a higher risk of CAC progression (Ptrend  < 0.001). Similar associations were found between sUA and IMT, but only in men.

CONCLUSION

sUA may be an early biomarker for subclinical atherosclerosis in young adults; starting in early middle age, sUA predicts subclinical atherosclerosis independently of BMI.

Gout as a risk factor for myocardial infarction and stroke in England: evidence from record linkage studies

OBJECTIVE

Some studies suggest that gout is a risk factor for cardiovascular disease. There is more evidence about the association between gout and acute myocardial infarction (MI) than about gout and stroke, and only limited information about risks by age group and sex. We aimed to study MI and stroke following gout, including types of stroke, by age group and comparing men and women.

METHODS

We analysed an all-England national linked dataset of hospital admissions and death records from 1999 to 2011, and a similar dataset in the Oxford Record Linkage Study spanning 1963-98. The occurrence of MI and stroke was estimated in cohorts of patients admitted to hospital with gout, compared with MI and stroke in control cohorts, and the comparisons were expressed as rate ratios (RRs).

RESULTS

The risk of MI and stroke was elevated, and similar, in both datasets. In the all-England dataset, which included 202 033 hospital patients with gout, the RR for MI following gout was 1.82 (95% CI 1.78, 1.85), for all stroke 1.71 (1.68, 1.75), ischaemic stroke 1.68 (1.64, 1.73), haemorrhagic stroke 1.69 (1.61, 1.77) and stroke of unspecified type 2.00 (1.95, 2.06). Associations were stronger in younger than older age groups, and in the younger were stronger in women than men.

CONCLUSION

Gout was associated with increased risk of stroke as well as MI. These findings should be considered by clinicians and may have implications for preventive management of circulatory disease risks in people with gout.

Elevated serum uric acid in nondiabetic people mark pro-inflammatory state and HDL dysfunction and independently predicts coronary disease

We explored the association of serum uric acid (UA) concentrations with pro-inflammatory state and high-density lipoprotein (HDL) dysfunction. UA tertiles in tracked 1,508 nondiabetic participants were analyzed cross-sectionally for associations with inflammation biomarkers and protective proteins over a mean follow-up of 4.9 years for incident coronary heart disease (CHD) using Cox proportional hazards regression. In the absence of metabolic syndrome (MetS), UA tertiles significantly distinguished, in each sex, increasing categories of three MetS components (inflammation/oxidation markers, apolipoprotein (apo)B) and (inversely) current smoking (but not protective proteins such as HDL, apoA-I, and adiponectin). Distinctions attenuated in the presence of MetS. Linear regression model revealed fasting triglycerides (1.86 mg/dl variance), male sex, and gamma-glutamyl transferase and age as covariates of UA levels in women. In Cox analysis, incident CHD (n = 137) was predicted by mid and upper UA tertile in men alone at significant hazard ratios of 2.7, additively to conventional risk factors. Elevated serum UA levels, linked to triglycerides, mark in nondiabetic people pro-inflammatory state, and, notably, HDL dysfunction. CHD risk is independently predicted by elevated UA levels in nondiabetic men and is modulated by MetS and gender.

Association of serum uric acid and cardiovascular disease in healthy adults

Studies in different populations with high risk for cardiovascular disease (CVD) have shown an association between serum uric acid (SUA) and CVD. However, only a few studies have demonstrated such an association in healthy populations. The aim of this study was to investigate the association between SUA and CVD in a cohort of men and women without diabetes or CVD. A retrospective study was conducted, with a mean 4.8-year follow-up. The outcome was the occurrence of a cardiovascular event, defined as the diagnosis of ischemic heart disease, acute coronary syndrome, acute myocardial infarction, or ischemic stroke. Mean SUA levels were 6.2 ± 1.1 mg/dl for men (n = 6,580) and 4.4 ± 1.1 mg/dl for women (n = 2,559). For women, the rate of CVD occurrence was 11.6% for the highest quartile of SUA level, compared with 5.0% to 6.5% for the lower 3 quartiles. For men, the rate of CVD occurrence was 14.0% for the highest quartile of SUA level, compared with 10.8% for the lowest quartile. The hazard ratio for CVD, adjusted for age, serum creatinine level, body mass index, systolic blood pressure, low-density lipoprotein cholesterol level, triglyceride level, plasma fasting glucose, physical activity, cardiovascular family history, use of diuretics, and current smoking, was 1.24 (95% confidence interval 1.08 to 1.41) for women and 1.06 (95% confidence interval 1.00 to 1.13) for men (p for interaction = 0.04). In conclusion, the strong association of SUA levels with CVD in women, compared with the much lesser degree in men, highlights the necessity of stratifying by gender in investigations of cardiovascular risk factors and supports exploration of SUA as a marker of CVD risk in healthy populations.

Synergistic effects of serum uric acid and cardiometabolic risk factors on early stage atherosclerosis: the cardiometabolic risk in Chinese study

OBJECTIVE

To comprehensively examine the associations of serum uric acid (SUA) with central and peripheral arterial stiffness in Chinese adults, and particularly assess the interactions between SUA and other cardiometabolic risk factors.

METHODS

The study included 3,772 Chinese men and women with carotid radial pulse wave velocity (crPWV), carotid femoral PWV (cfPWV), carotid artery dorsalis pedis PWV (cdPWV) and SUA measured.

RESULTS

After adjustment for age, sex, and BMI, the levels of SUA were significantly associated with increasing trend of cfPWV, crPWV and cdPWV (P for trend <0.0001). Further adjustment for heart rate (HR), blood pressure (BP) and lipids attenuated the associations with crPWV and cdPWV to be non-significant (P = 0.1, P = 0.099 respectively), but the association between SUV and cfPWV remained significant (P = 0.004). We found significant interactions between SUA and HR or BP in relation to cfPWV (P for interaction = 0.03, 0.003 respectively). The associations between SUA and cfPWV were more evident among individuals with higher HR or normal BP than those with lower HR or hypertension.

CONCLUSIONS

SUA was associated with elevated aortic arterial stiffness in Chinese adults, independent of conventional cardiovascular risk factors. BP and HR might modify the deleterious effects of SUA.

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.

Associations between serum uric acid and markers of subclinical atherosclerosis in young adults. The cardiovascular risk in Young Finns study

BACKGROUND AND METHODS

Serum uric acid (SUA) is a suggested biomarker for established coronary artery disease, but the role of SUA in early phases of atherosclerosis is controversial. The relations of SUA with vascular markers of subclinical atherosclerosis, including carotid artery intima-media thickness (cIMT), carotid plaque, carotid distensibility (Cdist) and brachial flow-mediated dilatation (FMD) were examined in 1985 young adults aged 30-45 years. In addition to ordinary regression, we used Mendelian randomization techniques to infer causal associations.

RESULTS

In women, the independent multivariate correlates of SUA included BMI, creatinine, alcohol use, triglycerides, glucose and adiponectin (inverse association) (Model R(2) = 0.30). In men, the correlates were BMI, creatinine, triglycerides, C-reactive protein, alcohol use, total cholesterol and adiponectin (inverse) (Model R(2) = 0.33). BMI alone explained most of the variation of SUA levels both in women and men (Partial R(2) ∼ 0.2). When SUA was modeled as an explanatory variable for vascular markers, it directly associated with cIMT and inversely with Cdist in age- and sex-adjusted analysis. After further adjustments for BMI or glomerular filtration rate, these relations were reduced to non-significance. No associations were found between SUA and FMD or the presence of a carotid plaque. Mendelian randomization analyses using known genetic variants for BMI and SUA confirmed that BMI is causally linked to SUA and that BMI is a significant confounder in the association between SUA and cIMT.

CONCLUSION

SUA is associated with cardiovascular risk markers in young adults, especially BMI, but we found no evidence that SUA would have an independent role in the pathophysiology of early atherosclerosis.

Relationships among hyperuricemia, endothelial dysfunction and cardiovascular disease: molecular mechanisms and clinical implications

Uric acid is the end product of purine metabolism. Its immediate precursor, xanthine, is converted to uric acid by an enzymatic reaction involving xanthine oxidoreductase. Uric acid has been formerly considered a major antioxidant in human plasma with possible beneficial anti-atherosclerotic effects. In contrast, studies in the past two decades have reported associations between elevated serum uric acid levels and cardiovascular events, suggesting a potential role for uric acid as a risk factor for atherosclerosis and related diseases. In this paper, the molecular pattern of uric acid formation, its possible deleterious effects, as well as the involvement of xanthine oxidoreductase in reactive oxygen species generation are critically discussed. Reactive oxygen species contribute to vascular oxidative stress and endothelial dysfunction, which are associated with the risk of atherosclerosis. Recent studies have renewed attention to the xanthine oxidoreductase system, since xanthine oxidoreductase inhibitors, such as allopurinol and oxypurinol, would be capable of preventing atherosclerosis progression by reducing endothelial dysfunction. Also, beneficial effects could be obtained in patients with congestive heart failure. The simultaneous reduction in uric acid levels might contribute to these effects, or be a mere epiphenomenon of the drug action. The molecular mechanisms involved are discussed.

Interaction between uric acid and endothelial dysfunction predicts new onset of diabetes in hypertensive patients

BACKGROUND

Both uric acid and endothelial dysfunction are associated with new occurrence of type-2 diabetes but, at this moment, there is no evidence about a possible interaction between them. We tested, in untreated hypertensive patients, without clinical evidence of vascular damage, the hypothesis that serum uric acid and endothelial dysfunction may interact in predicting new diabetes.

METHODS

In 500 uncomplicated hypertensive non diabetic (ADA criteria) patients we evaluated endothelial function, by strain-gauge plethysmography, and uric acid.

RESULTS

During the follow-up (median 87.1 months), there were 54 new cases of diabetes (1.8%/year). On univariate analysis, incident diabetes was inversely related with ACh-stimulated FBF (HR=0.65, 95%CI=0.52-0.82; P<0.001) and directly with serum CRP (HR=1.22, 95%CI=1.09-1.37; P<0.001), HOMA-index (HR=1.20, 95%CI=1.05-1.37; P=0.007), fasting insulin (HR=1.05, 95%CI=1.01-1.09; P=0.006) and age (HR=1.03, 95%CI=1.00-1.05; P=0.014). At multiple regression analysis, the interaction between ACh-stimulated FBF and uric acid resulted statistically significant. Similar results were observed for the interaction between FBF and CRP.

CONCLUSIONS

Our data clearly demonstrate that the coexistence of both hyperuricemia and reduced endothelium-dependent vasodilation increases the risk to develop new diabetes in hypertensive patients. In addition, mild-inflammation seems to be the mediator of the interaction between endothelial dysfunction and uric acid.

Uric acid is an independent risk factor for carotid atherosclerosis in a Japanese elderly population without metabolic syndrome

Background

Carotid intima-media thickness (IMT) is an useful surrogate marker of cardiovascular disease. Associations between uric acid (UA), metabolic syndrome (MetS) and carotid IMT have been reported, but findings regarding the relationship have been inconsistent.

Methods

A total of 1,579 Japanese elderly subjects aged ≥65 years {663 men aged, 78 ± 8 (mean ± standard deviation) years and 916 women aged 79 ± 8 years} were divided into 4 groups according to UA quartiles. We first investigated the association between UA concentrations and confounding factors including MetS; then, we assessed whether there is an independent association of UA with carotid IMT and atherosclerosis in participants subdivided according to gender and MetS status.

Results

Carotid IMT was significantly increased according to the quartiles of UA in both genders without MetS and women with MetS. Multivariate logistic regression analysis showed that odds ratio (OR) {95% confidence interval (CI)} in men for carotid atherosclerosis was significantly increased in the third (OR, 1.75; 95% CI, 1.02-3.02), and fourth quartiles (OR, 2.01; 95% CI, 1.12-3.60) of UA compared with that in the first quartile of UA, and the OR in women was significantly increased in the fourth quartile (OR, 2.10; 95% CI, 1.30-3.39). Similarly, the ORs were significantly associated with increasing quartiles of UA in both genders without MetS, but not necessarily increased in those with MetS.

Conclusions

UA was found to be an independent risk factor for incidence of carotid atherosclerosis in both genders without MetS.

Uric acid in heart disease: a new C-reactive protein?

PURPOSE OF REVIEW

To review and interpret the recently published data on hyperuricemia and cardiovascular disease to present an opinion on the nature of link between serum uric acid concentration and the risk for cardiovascular outcomes, and to comment on its implications for clinical practice.

RECENT FINDINGS

Evidence has accumulated in prospective observational studies that link hyperuricemia among younger adults with the risk of subsequent hypertension. Such associations have been observed with respect to insulin resistance, diabetes, and other cardiovascular risk factors. Newer data confirm the link between hyperuricemia and cardiovascular mortality. The use of allopurinol has been shown to be associated with reduced mortality risk in longer term observational studies and with reduced blood pressure in short-term randomized controlled trials. None of these findings is confounded by traditional risk factors.

SUMMARY

The available evidence has established a link between hyperuricemia and cardiovascular disease and this may be causal. Without waiting for the resolution of causality arguments, one can start using serum uric acid concentration as an inexpensive cardiovascular risk marker.

Joint and tendon subclinical involvement suggestive of gouty arthritis in asymptomatic hyperuricemia: an ultrasound controlled study

Introduction

In this study, we aimed to investigate ultrasonographic (US) changes suggestive of gouty arthritis in the hyaline cartilage, joints and tendons from asymptomatic individuals with hyperuricemia.

Methods

We conducted a cross-sectional, controlled study including US examinations of the knees and first metatarsal-phalangeal joints (first MTPJs), as well as of the tendons and enthesis of the lower limbs. Differences were estimated by χ² or unpaired t-tests as appropriate. Associations were calculated using the Spearman's correlation coefficient rank test.

Results

Fifty asymptomatic individuals with hyperuricemia and 52 normouricemic subjects were included. Hyperechoic enhancement of the superficial margin of the hyaline cartilage (double contour sign) was found in 25% of the first MTPJs from hyperuricemic individuals, in contrast to none in the control group (P < 0.0001). Similar results were found on the femoral cartilage (17% versus 0; P < 0.0001). Patellar enthesopathy (12% versus 2.9%; P = 0.01) and tophi (6% versus 0; P = 0.01) as well as Achilles enthesopathy (15% versus 1.9%; P = 0.0007) were more frequent in hyperuricemic than in normouricemic individuals. Intra-articular tophi were found in eight hyperuricemic individuals but in none of the normouricemic subjects (P = 0.003).

Conclusions

These data demonstrate that morphostructural changes suggestive of gouty arthritis induced by chronic hyperuricemia frequently occur in both intra- and extra-articular structures of clinically asymptomatic individuals.

Determinants of vascular function in patients with chronic gout

Epidemiologic studies have proposed a relationship between hyperuricemia and cardiovascular (CV) risk. However, it is unclear whether uric acid (UA) is an independent risk factor for CV disease (CVD) after controlling for other predisposing conditions. Gout patients might have persistent systemic inflammation, which, in addition to hyperuricemia, may potentiate CVD. This study examined vascular function and markers of CV damage in gout patients when compared with healthy controls. Brachial artery flow-mediated dilatation, arterial compliance, and microvascular function were measured. Circulating apoptotic endothelial cells and endothelial progenitor cells were quantified by FACS and circulating biomarkers of CVD by enzyme-linked immunosorbent assay. Gout patients displayed significant increases in body mass index, C-reactive protein, UA, and triglycerides and decreases in high-density lipoprotein. There were no significant differences in other CV traditional risk factors, adhesion molecules, or chemokines. Gout patients did not differ from controls in vascular function. In univariate and multivariate analysis, UA was not associated with the quantified CV risk parameters. Despite an increase in several CV risk factors, inflammation, and UA, gout patients display normal endothelial function and no increases in biomarkers of CVD. These results do not support the notion that gout is an independent risk factor for premature CVD.

Serum urate is not associated with coronary artery calcification: the NHLBI Family Heart Study

OBJECTIVE

urate may have effects on vascular remodeling and atherosclerosis. We had shown an association between serum uric acid (SUA) and carotid atherosclerotic plaques. Inflammation and vascular remodeling in atherosclerosis promote coronary artery calcification (CAC), a preclinical marker for atherosclerosis. Here, we examined whether SUA is associated with CAC, using the same study sample and methods as for our previous carotid atherosclerosis study.

METHODS

the national Heart, Lung, and Blood Institute Family Heart Study is a multicenter study designed to assess risk factors for heart disease. Participants were recruited from population-based cohorts in the US states of Massachusetts, North Carolina, Minnesota, Utah, and Alabama. CAC was assessed with helical computed tomography (CT). We conducted sex-specific and family-cluster analyses, as well as additional analyses among persons without risk factors related to both cardiovascular disease and hyperuricemia, adjusting for potential confounders as we had in the previous study of carotid atherosclerosis.

RESULTS

for the CAC study, 2412 subjects had both SUA and helical CT results available (55% women, age 58 ± 13 yrs, body mass index 27.6 ± 5.3). We found no association of SUA with CAC in men or women [OR in men: 1.0, 1.11, 0.86, 0.90; women: 1.0, 0.83, 1.00, 0.87 for increasing categories of SUA: < 5 (referent group), 5 to < 6, 6 to < 6.8, ≥ 6.8 mg/dl, respectively], nor in subgroup analyses.

CONCLUSION

replicating the methods used to demonstrate an association of SUA with carotid atherosclerosis did not reveal any association between SUA and CAC, suggesting that SUA likely does not contribute to atherosclerosis through effects on arterial calcification. The possibility that urate has divergent pathophysiologic effects on atherosclerosis and artery calcification merits further study.

Exposure to volatile organic compounds and kidney dysfunction in thin film transistor liquid crystal display (TFT-LCD) workers

Many volatile organic compounds (VOCs) are emitted during the manufacturing of thin film transistor liquid crystal displays (TFT-LCDs), exposure to some of which has been reported to be associated with kidney dysfunction, but whether such an effect exists in TFT-LCD industry workers is unknown. This cross-sectional study aimed to investigate the association between exposure to VOCs and kidney dysfunction among TFT-LCD workers. The results showed that ethanol (1811.0+/-1740.4 ppb), acetone (669.0+/-561.0 ppb), isopropyl alcohol (187.0+/-205.3 ppb) and propylene glycol monomethyl ether acetate (PGMEA) (102.9+/-102.0 ppb) were the four dominant VOCs present in the workplace. The 63 array workers studied had a risk of kidney dysfunction 3.21-fold and 3.84-fold that of 61 cell workers and 18 module workers, respectively. Workers cumulatively exposed to a total level of isopropyl alcohol, PGMEA and propylene glycol monomethyl ether> or =324 ppb-year had a significantly higher risk of kidney dysfunction (adjusted OR=3.41, 95% CI=1.14-10.17) compared with those exposed to <25 ppb-year after adjustment for potential confounding factors. These findings indicated that array workers might be the group at greatest risk of kidney dysfunction within the TFT-LCD industry, and cumulative exposure to specific VOCs might be associated with kidney dysfunction.

Uric acid transport and disease

Uric acid is the metabolic end product of purine metabolism in humans. It has antioxidant properties that may be protective but can also be pro-oxidant, depending on its chemical microenvironment. Hyperuricemia predisposes to disease through the formation of urate crystals that cause gout, but hyperuricemia, independent of crystal formation, has also been linked with hypertension, atherosclerosis, insulin resistance, and diabetes. We discuss here the biology of urate metabolism and its role in disease. We also cover the genetics of urate transport, including URAT1, and recent studies identifying SLC2A9, which encodes the glucose transporter family isoform Glut9, as a major determinant of plasma uric acid levels and of gout development.