Serum uric acid independently predicts mortality in patients with significant, angiographically defined coronary disease

A Ten-Year Follow-Up Study of the Association Between Uric Acid and Adverse Cardiovascular Events in Patients With Coronary Artery Disease

The association between uric acid (UA) and long-term mortality in patients with coronary artery disease is poorly investigated. We assessed the association between UA and 10-year mortality after percutaneous coronary intervention (PCI) in 3,998 patients who underwent PCI. Patients were categorized in groups according to UA tertiles: tertile 1 (UA <5.80 mg/100 ml, n = 1,347), tertile 2 (UA 5.80 to 7.04 mg/100 ml, n = 1,340), and tertile 3 (UA >7.94 mg/100 ml, n = 1,311). The primary outcome was 10-year all-cause mortality. All-cause deaths occurred in 1,200 patients: 320 deaths (26.5%) in patients with UA in the first tertile, 325 deaths (26.9%) in patients with UA in the second tertile, and 555 deaths (46.0%) in patients with UA in the third tertile (adjusted hazard ratio 1.22, 95% confidence interval 1.17 to 1.27, p <0.001) for 1 mg/100 ml increment in UA level. Cardiac deaths occurred in 748 patients: 194 deaths (16.5%) in patients with UA in the first tertile, 202 deaths (17.0%) in patients with UA in the second tertile, and 352 deaths (29.7%) in patients with UA in the third tertile (adjusted hazard ratio 1.24 [1.17 to 1.32], p <0.001) for 1 mg/100 ml increment in the UA level. The 10-year rates of target lesion revascularization, target vessel revascularization, or nontarget vessel revascularization did not differ significantly according to the UA level. In conclusion, in patients with coronary artery disease treated with PCI, increased UA level was associated with higher 10-year mortality. Increased UA level was not associated with the progression of atherosclerosis in nontreated coronary vessels or progression of intimal hyperplasia in stented lesions requiring intervention.

High-level uric acid in asymptomatic hyperuricemia could be an isolated risk factor of cardio-cerebrovascular diseases: A prospective cohort study

BACKGROUND AND AIMS

Whether the asymptomatic hyperuricemia (AH) raise the cardiovascular disease risk with or without hyperuricemia-related comorbidities still remains contentious. Our study was aimed to quantitatively access the incidence risk of coronary heart disease (CHD) and stroke associated with AH.

METHODS AND RESULTS

In this prospective cohort study, multivariate-adjusted Cox regression models were applied to evaluate the risk of cardiovascular disease (CVD). Baseline serum uric acid beyond normouricemia (357 mmol/L) was quarterly stratified based on the distribution of healthy populations without CVD onset. 1062 CVD first-attack cases were collected among the 29,974 study population (age range: 18-91, mean age: 47.2 ± 13.9 years-old) with a mean follow-up duration of 5.78 ± 0.83 years. The AH showed overall non-association with the CVD incident. However, significantly increased adjusted hazard ratio (HR) of CVD with 95% confidence interval (CI) were observed when the fourth quartile compared with normouricemia stratum in the total cohort population (CHD: 1.42, 1.21-1.68; stroke: 1.27, 1.06-1.41), male (CHD: 1.26, 1.12-1.55), female (CHD: 1.34, 1.04-2.02; stroke: 2.06, 1.13-3.77) and aged over 50 years-old population. Meanwhile, the age-standardized incidence rate of CVD in the fourth quartile was 2-3 times higher than the normouricemia population. After excluded 14,464 baseline population with diabetes, dyslipidemia, and hypertension, consistent results were also observed in the AH population in absence of comorbidities (CHD: 1.51, 1.22-2.25; stroke: 1.68, 1.13-2.39).

CONCLUSION

Asymptomatic hyperuricemia patients exposed to a higher level of uric acid (>=428 mmol/L) could significantly increase the incidence risk of CHD and stroke, with or without hyperuricemia-related comorbidities.

Hyperuricemia in Patients With Coronary Artery Disease and Its Association With Disease Severity

The biochemical background of coronary artery disease (CAD) has been intensively explored in the past several decades. Previous clinical investigations have demonstrated the association of non-traditional risk factors, such as hyperuricemia, with CAD. Studies have shown that increased serum uric acid (SUA) was associated with an increased risk of adverse cardiovascular (CV) outcomes in patients with CAD. While the exact pathophysiological mechanisms leading to increased risk are still unknown, it has been postulated that hyperuricemia leads to endothelial dysfunction, oxidative metabolism, and platelet adhesiveness and aggregation, leading to CAD. Moreover, previous studies have shown that hyperuricemia is an independent risk factor for CAD. However, the correlation between high SUA levels and the severity of CAD remains unclear. The purpose of this review was to elucidate the association of hyperuricemia to CAD severity and to determine the effect of urate-lowering therapy (ULT) on CAD. A search of PubMed up to June 24, 2021, was carried out by the reviewers. From the findings, hyperuricemia stands as an independent risk factor for CAD, and CAD patients treated with ULT had improved CV outcomes and reduced mortality. Therefore, while SUA level is valuable in predicting an augmented risk of CAD and anticipating worse outcomes, ULT has promising cardioprotective effects.

Using multiple Mendelian randomization approaches and genetic correlations to understand obesity, urate, and gout

Observational studies suggest relationships between obesity, urate, and gout but are possibly confounded. We assessed whether genetically determined obesity, higher urate (and related traits), and gout were causal using multiple Mendelian randomization (MR) approaches and linkage disequilibrium score regression for genetic correlations (rg). For data, we used genome-wide association study summary statistics available through MR-Base. We observed that obesity increased urate (beta = 0.127; 95% CI = 0.098, 0.157; P-value = 1.2E-17; rg = 0.25 [P-value = 0.001]) and triglycerides (beta = 0.082; 95% CI = 0.065, 0.099; P-value = 1.2E-21; rg = 0.23 [P-value = 8.8E-12]) and decreased high-density lipoprotein cholesterol (HDL) (beta = - 0.083; 95% CI = - 0.101, - 0.065; P-value = 2.5E-19; rg = - 0.28; [P-value = 5.2E-24]). Higher triglycerides increased urate (beta = 0.198; 95% CI = 0.146, 0.251; P-value = 8.9E-14; rg = 0.29 [P-value = 0.001]) and higher HDL decreased urate (beta = - 0.109; 95% CI = - 0.148, - 0.071; P-value = 2.7E- 08; rg = - 0.21 [P-value = 9.8E-05]). Higher urate (OR = 1.030; 95% CI = 1.028, 1.032; P-value = 1.1E-130; rg = 0.89 [P-value = 1.7E-55]) and obesity caused gout (OR = 1.003; 95% CI = 1.001, 1.004; P-value = 1.3E-04; rg = 0.23 [P-value = 2.7E-05]). Obesity on gout with urate as a mediator revealed all the effect of obesity on gout occurred through urate. Obesity on low-density lipoprotein cholesterol (LDL) was null (beta = -0.011; 95% CI = -0.030, 0.008; P-value = 2.6E-01; rg = 0.03 [P-value = 0.369]). A multivariable MR of obesity, HDL, and triglycerides on urate showed obesity influenced urate when accounting for HDL and triglycerides. Obesity's impact on urate was exacerbated by it decreasing HDL.

Hepatic Accumulation of Hypoxanthine: A Link Between Hyperuricemia and Nonalcoholic Fatty Liver Disease

BACKGROUND

An elevated level of plasma uric acid has been widely recognized as a risk factor for non-alcoholic fatty liver disease (NAFLD), where oxidative stress and inflammation play an important role in the pathophysiology of the disease. Although the complete molecular mechanisms involved remain unknown, while under physiological conditions uric acid presents antioxidant properties, hyperuricemia has been linked to oxidative stress, chronic low-grade inflammation, and insulin resistance, basic signs of NAFLD.

AIM OF STUDY

Employing in vivo experimentation, we aim to investigate whether a high-fat diet rich in cholesterol (HFD), modifies the metabolism of purines in close relationship to molecular events associated with the development of NAFLD. In vitro experiments employing HepG2 cells are also carried out to study the phenomenon of oxidative stress.

METHODS

Adult male rabbits were fed for 8 weeks an HFD to induce NAFLD. At the beginning of the experiment and every 15 d until the completion of the study, plasma levels of lipids, lipoproteins, and uric acid were measured. Liver tissue was isolated, and histology performed followed by the biochemical determination of hypoxanthine, protein expression of xanthine oxidoreductase (XOR) by western blot analysis, and xanthine oxidase (XO) activity using an enzymatic kinetic assay. Furthermore, we employed in vitro experimentation studying HepG2 cells to measure the effect of hypoxanthine and H₂O₂ upon the production of radical oxygen species (ROS), XO activity, and cell viability.

RESULTS AND CONCLUSION

Hepatic tissue from rabbits fed the HFD diet showed signs of NAFLD associated with an increased ROS concentration and an altered purine metabolism characterized by the increase in hypoxanthine, together with an apparent equilibrium displacement of XOR towards the xanthine dehydrogenase (XDH) isoform of the enzyme. This protein shift visualized by a western blot analysis, associated with an increase in plasma uric acid and hepatocyte hypoxanthine could be understood as a compensatory series of events secondary to the establishment of oxidative stress associated with the chronic establishment of fatty liver disease.

Elevated postoperative serum uric acid is associated with major adverse events following coronary artery bypass grafting

BACKGROUND

Few data are available on the association between postoperative serum uric acid (SUA) level and poor survival in patients undergoing coronary artery bypass grafting (CABG). We evaluated the relationship between postoperative SUA and major adverse cardiac and cerebrovascular events (MACCE) among patients undergoing CABG.

METHODS

This study used data from 1614 consecutive patients undergoing CAGB at Fuwai Hospital (Beijing, China) from 2011 to 2015. Patients were stratified into statistical quartiles of postoperative SUA (between 6 and 18 hours after cardiac surgery): less than 203.7, 203.7 to 254.1, 254.1 to 316.6, and ≥316.6 µmol/L. The association of postoperative SUA with MACCE (ie, death, myocardial infarction [MI], stroke, or repeat revascularization) and the composite endpoint of mortality/MI were assessed.

RESULTS

Patients had a mean age of 60.3 ± 8.4 years, and 79.3% were male. During mean follow-up of 2.5 ± 0.7 years, MACCE occurred in 201 (12.5%) patients. In separate multivariable regression models, postoperative SUA level was positively associated with in-hospital MACCE (highest vs lowest SUA quartile: odds ratio [OR]: 2.40; 95% confidence interval [CI]: 1.29, 4.48; P = .006) and in-hospital composite endpoint of mortality/MI (OR: 2.88; 95% CI: 1.45, 5.72; P = .003), respectively. And elevated postoperative SUA level was independently associated with MACCE (Hazard ratio [HR]: 1.70; 95% CI: 1.12, 2.57; P = .01) and the composite endpoint of mortality/MI (HR: 2.42; 95% CI: 1.32, 4.43; P = .004) respectively within 3 years after CABG.

CONCLUSIONS

Elevated postoperative SUA level is associated with poor clinical outcomes after CABG. Patients with high postoperative SUA levels after CABG might require to be closely monitored.

Prevalence of metabolic syndrome and its associated factors in Chinese patients with ankylosing spondylitis

Purpose: We assessed the prevalence of metabolic syndrome (MetS) and associated factors in mainland Chinese patients with ankylosing spondylitis (AS). Patients and methods: A retrospective study was conducted in 117 AS patients and 117 age- and sex-matched healthy controls. Parameters of MetS based on the criteria established by the Chinese Diabetes Society in 2013 were tabulated. Demographic features, laboratory data, and clinical characteristics were also collected. Independent factors correlated with MetS in AS patients were identified by backward stepwise multivariate analysis. Results: The prevalence of MetS was higher in AS patients than in healthy controls (P= 0.026). AS patients also had higher blood pressure and fasting serum glucose levels, but generally lower serum lipid levels. AS patients with and without MetS had no distinct differences in disease duration, medication usage, disease activity, or biomarkers of inflammation. Multivariable logistic regression analysis showed that hyperuricemia (odds ratio [OR] = 2.385, 95% confidence interval [95% CI] = 1.019-5.582, P= 0.045) and high body mass index (BMI, OR = 5.165; 95% CI = 1.935-13.787, P=0.001) were independent factors for MetS in AS patients. Conclusion: Chinese AS patients living in the mainland have an increased risk of developing MetS. Hyperuricemia and high BMI are predictors of MetS in AS patients.

Serum uric acid level predicts adverse outcomes after myocardial revascularization or cardiac valve surgery

Background

High levels of serum uric acid have been associated with adverse outcomes in cardiovascular diseases such as myocardial infarction and heart failure. The aim of the current study was to evaluate the prognostic role of serum uric acid levels in patients undergoing cardiac rehabilitation after myocardial revascularization and/or cardiac valve surgery.

Design

We performed an observational prospective cohort study.

Methods

The study included 1440 patients with available serum uric acid levels, prospectively followed for 50 ± 17 months. Mean age was 67 ± 11 years; 781 patients (54%) underwent myocardial revascularization, 474 (33%) cardiac valve surgery and 185 (13%) valve-plus-coronary artery by-pass graft surgery. The primary endpoints were overall and cardiovascular mortality while secondary end-points were combined major adverse cardiac and cerebrovascular events.

Results

Serum uric acid level mean values were 286 ± 95 µmol/l and elevated serum uric acid levels (≥360 µmol/l or 6 mg/dl) were found in 275 patients (19%). Overall mortality (hazard ratio = 2.1; 95% confidence interval: 1.5–3.0; p < 0.001), cardiovascular mortality (hazard ratio = 2.0; 95% confidence interval: 1.2–3.2; p = 0.004) and major adverse cardiac and cerebrovascular events rate (hazard ratio = 1.5; 95% confidence interval: 1.0–2.0; p = 0.019) were significantly higher in patients with elevated serum uric acid levels, even after adjustment for age, gender, arterial hypertension, diabetes, glomerular filtration rate, atrial fibrillation and medical therapy. Moreover, strong positive correlations between serum uric acid level and probability of overall mortality ( p < 0.001), cardiovascular mortality ( p < 0.001) and major adverse cardiac and cerebrovascular events ( p = 0.003) were found.

Conclusions

Serum uric acid levels predict mortality and adverse cardiovascular outcome in patients undergoing myocardial revascularization and/or cardiac valve surgery even after the adjustment for age, gender, arterial hypertension, diabetes, glomerular filtration rate and medical therapy.

Hyperuricemia as an independent risk factor for major cardiovascular events: a 10-year cohort study from Southern Italy

AIMS

To date, whether hyperuricemia may represent a marker or an independent risk factor for cardiovascular disease remains unclear. This study aimed at assessing the role of hyperuricemia in the onset of major cardiovascular events (MACE).

METHODS

Baseline clinical data were collected through a 1998/1999 longitudinal survey as part of the larger Valle dell'Irno Prevenzione Project. Ten years later, MACE incidence was evaluated.

RESULTS

A total of 1175 patients (50% men, aged 25-74 years) completed the study. At least one MACE was reported by 135 patients, whose mean uric acid values were significantly higher compared with patients without events (6.0 ± 4.8 and 4.6 ± 4.0 mg/dl, respectively; P < 0.01). Patients with uric acid values of at least 6 mg/dl (prevalence of 14.6%) had significantly lower levels of high-density lipoprotein cholesterol and increased values of BMI, blood pressure (BP), cholesterol, triglycerides, white blood cells, complement component 3 (C3) and creatinine. After subgrouping patients in tertiles and considering the first one as reference [odds ratio (OR): 1], the OR (95% confidence interval) was 1.44 (0.7-2.9) in the second and 2.2 (1.3-3.5) in the third tertile, respectively. Confounder-adjusted stepwise linear regression revealed uric acid, age, creatinine, glucose and systolic BP as independent predictors of MACE. Diastolic BP and creatinine were independently correlated with uric acid in the entire population, diastolic BP only in men and BMI, creatinine, age and C3 in women.

CONCLUSION

Hyperuricemia was shown to be a strong independent risk factor for MACE and should be included in cardiovascular prevention strategies. Whether hypouricemic drugs can decrease cardiovascular disease risk warrants further studies.

Hyperuricemia and risk of increased arterial stiffness in healthy women based on health screening in Korean population

Hyperuricemia is a risk factor for cardiovascular disease and is associated with increased arterial stiffness in high-risk populations. However, given the possible sex-related differences in the prevalence of hyperuricemia, the association between elevated serum uric acid (SUA) level and increased arterial stiffness has yielded conflicting results. We investigated the relationship between SUA and arterial stiffness in asymptomatic healthy subjects who underwent a health examination. Subjects who underwent a comprehensive health examination were enrolled. After exclusion of extensive confounding factors, 2,704 healthy subjects with coronary calcium score < 100 were evaluated in the final analysis. All subjects underwent brachial—ankle pulse wave velocity (baPWV) to detect arterial stiffness. The SUA was divided into quartiles for its association with arterial stiffness and was analyzed separately for men and women. The mean SUA level was significantly lower in women than in men. The baPWV was significantly elevated in subjects with the highest quartile of SUA in women, but not in men. After adjusting for age, smoking, systolic blood pressure, body mass index, estimated glomerular filtration rate, fasting plasma glucose, high-density lipoprotein-cholesterol, low-density lipoprotein-cholesterol, and coronary artery calcium score, the highest quartile of SUA in women was significantly associated with increased risk of high baPWV compared with the lowest quartile of SUA (OR = 1.7, p = 0.018), whereas in men, SUA level was not associated with high baPWV. Our study showed that elevated SUA is independently associated with increased baPWV in healthy Korean women, but not in men.

An examination of the relationship between serum uric acid level, a clinical history of gout, and cardiovascular outcomes among patients with acute coronary syndrome

BACKGROUND

Studies have suggested a relationship between higher baseline serum uric acid (sUA) levels and an elevated risk of subsequent ischemic cardiovascular outcomes among acute coronary syndrome (ACS) patients; this relationship may be modified by a clinical history of gout and has not been studied in large patient cohorts. We sought to understand the effect of sUA and gout on ACS outcomes.

METHODS

Using PLATO and TRACER data on 27,959 ACS patients, we evaluated baseline sUA levels in relation to a composite of cardiovascular death, myocardial infarction (MI), or stroke. We assessed interaction terms to determine if a baseline clinical diagnosis of gout modified this putative relationship; 46% (n=12,882) had sUA levels elevated >6.0 mg/dL.

RESULTS

Patients with elevated levels were more often male with a history of prior MI, diabetes, and heart failure compared with those with sUA <6.0 mg/dL. The unadjusted risk of the composite endpoint increased with corresponding elevations in sUA levels (per 1 mg/dL increase) (HR=1.23 [95% CI: 1.20-1.26]) above the statistical inflection point of 5.0 mg/dL. After adjustment, the association between sUA level and the composite outcome remained significant (HR=1.07 [95% CI: 1.04-1.10]), and baseline gout did not modify this relationship.

CONCLUSIONS

In patients with ACS, increasing levels of sUA are associated with an elevated risk of cardiovascular events, regardless of a clinical diagnosis of gout. Further investigation is warranted to determine the mechanism behind this relationship and to delineate whether sUA is an appropriate therapeutic target to reduce cardiovascular risk.

Does Uric Acid Level Provide Additional Risk Stratification Information in Emergency Patients With Symptoms of Possible Acute Coronary Syndrome?

OBJECTIVE

Elevated uric acid levels have been associated with the presence and severity of coronary artery disease (CAD). This study aimed to assess the clinical utility of serum uric acid levels to identify patients at high risk of acute coronary syndrome (ACS) in those who presented to the emergency department (ED) with chest pain.

METHODS

This was a prospective observational study of 951 adult patients who were being evaluated for ACS in a single ED. Serum uric acid was taken on presentation. Patients were followed up 30 days and 1 year after initial presentation. The primary outcome was a diagnosis of ACS within 30 days of initial attendance. A logistic regression analysis was performed to identify whether elevated uric acid levels were predictive of ACS. Kaplan-Meier curves were generated to identify 1-year mortality in those who were available for 1-year follow-up and Cox regression was performed to identify whether uric acid levels were an independent predictor of mortality.

RESULTS

ACS was diagnosed in 88 patients and 140 patients had elevated uric acid levels. A total of 679 patients agreed to 1-year follow-up. Elevated uric acid levels were not associated with a diagnosis of ACS (p = 0.96). Patients with elevated uric acid had a higher 1-year death rate (8/101; 7.92%) compared with patients with normal uric acid levels (12/596; 2.01%, p < 0.01).

CONCLUSIONS

Uric acid levels lack diagnostic utility for ACS but may be useful for identifying ED patients with chest pain who are at high risk for 1-year mortality. Elevated uric acid levels correlate with the presence of other risk factors of CAD and are a marker for poor long-term outcome.

Elevated serum uric acid and risk of cardiovascular or all-cause mortality in people with suspected or definite coronary artery disease: A meta-analysis

BACKGROUND AND AIMS

Serum uric acid (SUA) has been recognized as an independent risk factor for mortality in the general population. We performed this meta-analysis to determine whether elevated SUA levels are associated with greater risk of cardiovascular or all-cause mortality in people with suspected or definite coronary artery disease (CAD).

METHODS

The Pubmed and Embase databases were searched up to April 1, 2016 for the longitudinal studies that investigated the association between the elevated SUA and cardiovascular or all-cause mortality risk in people with suspected or definite CAD. Pooled adjusted risk ratio (RR) and corresponding 95% confidence interval (CI) were calculated for the highest vs. the lowest SUA category or each 1 mg/ml SUA rise.

RESULTS

Nine studies enrolling 25,229 participants were included in the analyses. The highest vs. lowest SUA category was associated with greater risk of cardiovascular mortality (RR 2.09; 95% CI: 1.45-3.02) and all-cause mortality (RR 1.80; 95% CI: 1.39-2.34) after adjustment for potential confounders in a random effects model. Moreover, each 1 mg/ml SUA rise significantly increased by 12% cardiovascular mortality and by 20% all-cause mortality.

CONCLUSIONS

Elevated SUA levels are strongly and independently associated with greater risk of cardiovascular and all-cause mortality in people with suspected or definite CAD.

Serum Uric Acid Levels and Renal Impairment among ST-Segment Elevation Myocardial Infarction Patients Undergoing Primary Percutaneous Intervention

BACKGROUND

Elevated serum uric acid (UA) levels are associated with adverse outcomes in ST-segment elevation myocardial infarction (STEMI) patients undergoing primary percutaneous coronary intervention (PCI). However, the relation between UA and acute kidney injury (AKI) in this population is unclear. We evaluated the effect of elevated UA levels on the risk to develop AKI among consecutive STEMI patients treated with primary PCI.

METHODS

We performed a retrospective analysis of 1,372 consecutive patients admitted with the diagnosis of STEMI between January 2008 and February 2015. Patients were stratified into quartiles according to UA levels as follows: quartile 1, <4.7 mg/dl; quartile 2, 4.8 to <5.6 mg/dl; quartile 3, 5.7 to <6.6 mg/dl, and quartile 4, >6.7 mg/dl.

RESULTS

STEMI patients with elevated UA levels had a higher frequency of AKI (4 vs. 6% vs. 10 vs. 24%; p < 0.001). In a subgroup analysis of patients with reduced baseline estimated glomerular filtration rate (≤60 ml/min/1.73 m(2)), an elevated UA level was associated with a significant risk to develop AKI, with 46% of patients developing AKI in the highest UA quartile. In a multivariate logistic regression model, for every 1-mg/dl increase in the UA concentration, the adjusted risk for AKI increased by 46% (OR = 1.46, 95% CI 1.18-1.66; p < 0.001).

CONCLUSIONS

Among STEMI patients undergoing primary PCI, elevated UA levels are an independent predictor of AKI.

Gender differences in the association between serum uric acid and prognosis in patients with acute coronary syndrome

BACKGROUND

Increased levels of uric acid (UA) have been associated with cardiovascular disease. This association is generally stronger in women than men. However, gender differences in the prognostic value of UA in patients with acute coronary syndrome (ACS) are unknown. We investigated gender differences in the relationship between UA level and the prognosis in patients with ACS.

METHOD

This was an observational analysis of patients with ACS undergoing percutaneous coronary intervention enrolled in the Ibaraki Cardiac Assessment Study (ICAS) registry. We analyzed 1380 patients (330 women, 1050 men) with ACS who had information on UA. We assessed the association between UA and the incidence of major cardiovascular adverse events (MACE), defined as all-cause death, congestive heart failure, reinfarction, and stroke. Patients were divided according to gender-specific UA quartile.

RESULTS

The mean UA level in women was significantly lower than that in men (4.9mg/dl vs 5.9mg/dl, p<0.001). After a median duration of follow-up period of 437 days (interquartile range 222-801 days), MACE had occurred in 186 (13%) patients [56 (17%) events in women; 130 (12%) events in men]. Kaplan-Meier analysis for MACE-free survival demonstrated that a higher quartile of UA was associated with MACE in both women and men (p<0.001, p=0.002, respectively). Multivariate Cox regression analysis revealed that the highest quartile of UA, as compared with the lowest quartile of UA, was an independent predictor of MACE in women [hazard ratio (HR), 2.84; 95% CI, 1.19-6.77; p=0.018] but not in men (HR, 1.32; 95% CI, 0.66-2.64; p=0.422).

CONCLUSIONS

An increased level of UA was associated with MACE more strongly in women than in men with ACS. These results suggest that there are gender differences in the association of UA level with the prognosis in patients with ACS.

Potential role of uric acid in metabolic syndrome, hypertension, kidney injury, and cardiovascular diseases: is it time for reappraisal?

Elevated serum uric acid concentration is a common laboratory finding in subjects with metabolic syndrome/obesity, hypertension, kidney disease and cardiovascular events. Hyperuricemia has been attributed to hyperinsulinemia in metabolic syndrome and to decreased uric acid excretion in kidney dysfunction, and is not acknowledged as a main mediator of metabolic syndrome, renal disease, and cardiovascular disorder development. However, more recent investigations have altered this traditional view and shown, by providing compelling evidence, to support an independent link between hyperuricemia and increased risk of metabolic syndrome, diabetes, hypertension, kidney disease and cardiovascular disorders. However, despite these new findings, controversy regarding the exact role of uric acid in inducing these diseases remains to be unfolded. Furthermore, recent data suggest that the high-fructose diet in the United State, as a major cause of hyperuricemia, may be contributing to the metabolic syndrome/obesity epidemic, diabetes, hypertension, kidney disease and cardiovascular disorder. Our focus in this review is to discuss the available evidence supporting a role for uric acid in the development of metabolic syndrome, hypertension, renal disease, and cardiovascular disorder; and the potential pathophysiology mechanisms involved.

Serum uric Acid is not an independent risk factor for premature coronary artery disease

BACKGROUND/AIM

There is still debate on the role of serum uric acid as an independent risk factor for coronary artery disease (CAD), particularly premature CAD. This study aimed to investigate whether serum uric acid is a risk factor for premature CAD and whether it can influence the severity of coronary artery stenosis.

METHODS

Candidates for coronary artery angiography (age <45 years for men and <55 years for women) who met the inclusion criteria were enrolled in this study. Clinical data of the patients as well as their serum uric acid levels were compared with the presence of premature CAD.

RESULTS

In total, 473 patients were included and divided into two groups: the premature CAD group consisted of 245 patients (age = 46.2 ± 5.7 years; males = 110, 44.9%) and the normal coronary group consisted of 228 subjects (age = 45.7 ± 6.4 years; males = 62, 27.2%). Uric acid was significantly related to the presence of CAD, but this relationship was not significant after adjustment for confounding variables, including classic CAD risk factors. CAD patients were then categorized based on the extent of the disease (from minimal CAD to three-vessel disease); however, unlike the classic risk factors of CAD, uric acid was not significantly different between these groups (p = 0.10), and a similar result was observed after adjustment for confounders.

CONCLUSION

Uric acid is not an independent risk factor for premature CAD but is weakly correlated with the extent of the disease; nevertheless, this relationship requires further investigation.

Uric acid induces oxidative stress and growth inhibition by activating adenosine monophosphate-activated protein kinase and extracellular signal-regulated kinase signal pathways in pancreatic β cells

Hyperuricaemia is a disorder of purine metabolism, and is strongly associated with insulin resistance and abnormal glucose metabolism. As the producer of insulin, pancreatic β cells might be affected by elevated serum uric acid levels and contribute to the disregulated glucose metabolism. In this study, we investigated the effect of high uric acid on rat pancreatic β cell function. Under high uric acid condition, proliferation of pancreatic β cells was inhibited, production of reactive oxygen species increased, and glucose stimulated insulin secretion was also compromised. Further examination on signal transduction pathways revealed that uric acid-induced ROS is involved in the activation of adenosine monophosphate-activated protein kinase (AMPK), and extracellular signal-regulated kinase (ERK). Pharmacological inhibition of ERK activation rescued β cells from growth inhibition. More importantly, activation of ERK induced by uric acid is significantly diminished by AMPK inhibitor, indicating ERK as a downstream target of AMPK in response to high uric acid condition. We also investigated the transportation channel for uric acid into pancreatic β cells. While major urate transporter URAT1 is not expressed in β cells, organic anion transporter (OAT) inhibitor successfully blocked the activation of ERK by uric acid. Our data indicate that high uric acid levels induce oxidative damage and inhibit growth of rat pancreatic β cells by activating the AMPK and ERK signal pathways. Hyperuricemia may contribute to abnormal glucose metabolism by causing oxidative damage and function inhibition of pancreatic β cells.

Uric acid and prognosis in angiography-proven coronary artery disease

BACKGROUND

The optimal uric acid (UA) level associated with the lowest mortality and the strength of association between UA and mortality in various subgroups of patients with coronary artery disease (CAD) are unknown.

MATERIALS AND METHODS

This study included 13 273 patients with angiographic confirmation of CAD and UA measurements available. The primary outcome analysis was 1-year mortality.

RESULTS

Based on the receiver operating characteristic curve analysis, the best cut-off of UA for mortality prediction was 7·11 mg/dL. Using this cut-off, patients were divided into two groups: the group with UA ≤ 7·11 mg/dL (n = 9075) and the group with UA > 7·11 mg/dL (n = 4198). Cardiac mortality was 6·3% (256 deaths) in patients with UA > 7·11 mg/dL and 2·3% (201 deaths) in patients with UA ≤ 7·11 mg/dL [hazard ratio (HR) = 2·82, 95% confidence interval (CI) 2·36-3·36; P < 0·001]. After adjustment for cardiovascular risk factors, UA remained an independent correlate of cardiac mortality (HR = 1·20, 95% CI 1·08-1·34; P = 0·001, for each standard deviation increase in the logarithmic scale of UA). The relationship between cardiac or all-cause mortality and UA showed a J-shaped pattern with lowest mortality in patients with UA between 5·17 and 6·76 mg/dL. UA predicted mortality across all subgroups of patients, with strongest association in women and patients without arterial hypertension.

CONCLUSIONS

UA predicted an increased risk of cardiac mortality across all subgroups of patients with CAD. The association between UA and cardiac or all-cause mortality had a 'J-shaped' pattern with lowest risk of death in patients with UA levels between 5·17 and < 6·76 mg/dL.

Comparison of the efficacy and safety of single-pill fixed-dose combinations of losartan/hydrochlorothiazide and valsartan/hydrochlorothiazide in patients with hypertension (SALT-VAT study)

OBJECTIVE

We analyzed the efficacy and safety of Preminent(®) [losartan (50 mg/day)/HCTZ (12.5 mg/day)] compared to CodioMD(®) [valsartan (80 mg/day)/HCTZ (6.25 mg/day)].

METHODS

In this study, 31 hypertensive patients after receiving 3 months of Preminent(®) (Stage A) were enrolled. We applied a changeover with switching from Preminent(®) to CodioMD(®) (Stage B). We then applied another changeover with switching from CodioMD(®) to Preminent(®) after 3 months (Stage C).

RESULTS

Average values of 24-h blood pressure (BP), daytime BP and nighttime BP using ambulatory BP monitoring (ABPM) significantly increased from Stage A to B [4/3 mmHg, 5/3 mmHg and 3/3 mmHg, respectively]. Average values of 24-h BP, morning BP, daytime BP, nighttime BP significantly decreased from the end of Stage B to C [-5/-5 mmHg, -4/-6 mmHg, -5/-5 mmHg and -6/-4 mmHg, respectively]. Interestingly, the serum levels of uric acid and the urinary albumin/creatinine ratio showed a significant increase after the change to CodioMD(®). Since these adverse effects did not disappear after the return to Preminent(®) at the end of Stage C, we performed an additional 3-month follow-up (extended stage). These adverse effects finally disappeared at the end of this extended stage.

CONCLUSION

Single-pill fixed-dose combination therapy using Preminent(®) showed significant 24-h BP-lowering effects and was safe when compared with CodioMD(®).

Association of renal manifestations with serum uric acid in Korean adults with normal uric acid levels

Several studies have reported that hyperuricemia is associated with the development of hypertension and cardiovascular disease. Increasing evidences also suggest that hyperuricemia may have a pathogenic role in the progression of renal disease. Paradoxically, uric acid is also widely accepted to have antioxidant activity in experimental studies. We aimed to investigate the association between glomerular filtration rate (GFR) and uric acid in healthy individuals with a normal serum level of uric acid. We examined renal function determined by GFR and uric acid in 3,376 subjects (1,896 men; 1,480 women; aged 20-80 yr) who underwent medical examinations at Gangnam Severance Hospital from November 2006 to June 2007. Determinants for renal function and uric acid levels were also investigated. In both men and women, GFR was negatively correlated with systolic and diastolic blood pressures, fasting plasma glucose, total cholesterol, uric acid, log transformed C reactive protein, and log transformed triglycerides. In multivariate regression analysis, total uric acid was found to be an independent factor associated with estimated GFR in both men and women. This result suggests that uric acid appears to contribute to renal impairment in subjects with normal serum level of uric acid.

Gout, hyperuricemia, and the risk of cardiovascular disease: cause and effect?

Gout and hyperuricemia have long been suspected to be risk factors for cardiovascular disease. However, studies have frequently failed to distinguish whether these entities have an independent effect on cardiovascular risk or serve as markers for other risk factors. In vitro and animal studies suggest that uric acid is a biologically active compound that can increase inflammatory mediators known to lead to vascular damage. In contrast, uric acid also has potentially protective effects as a strong antioxidant, approaching the potency of vitamin C. Large clinical trials demonstrate a consistent relationship between elevated serum uric acid and a variety of cardiovascular diseases, although the strength of association varies greatly. We review the evidence for and against an independent role for hyperuricemia and/or gout in cardiovascular pathology.

Epidemiological association between uric acid concentration in plasma, lipoprotein(a), and the traditional lipid profile

BACKGROUND

Elevated levels of uric acid in serum (SUA) or plasma (PUA) are increasingly related to cardiovascular disease. It is unclear whether they are independent risk factors or simply markers, reflecting association with other traditional risk factors.

METHODS

We retrospectively assessed results of a lipid profile, including total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides, total cholesterol to HDL-C ratio (TC/HDL-C), the atherogenic index of plasma (AIP), and lipoprotein(a) (Lp[a]), in a large cohort of unselected adult outpatients.

RESULTS

Hyperuricemic men displayed significantly increased values of triglycerides and AIP when compared with men with normal PUA levels. In hyperuricemic women, significant differences were observed for HDL-C, triglycerides, TC/HDL-C, and AIP compared with women with normal PUA levels. The percentage of patients with unfavorable values was statistically higher for triglycerides and AIP in hyperuricemic men; for HDL-C, triglycerides, TC/HDL-C, and AIP in hyperuricemic women. In multivariable linear regression analysis triglycerides, AIP, and TC/HDL-C were independently associated with PUA in women, whereas no significant association was observed in men.

CONCLUSION

PUA measurement might be advisable in patients to identify those at increased risk of cardiovascular disease (CVD) who might benefit from further triage and intervention.

The potential for xanthine oxidase inhibition in the prevention and treatment of cardiovascular and cerebrovascular disease

There is a now a wealth of epidemiological, animal, and clinical data to suggest the benefits of uric acid reduction and hxanthine oxidase inhibition in prevention of vascular disease. This review discusses the available epidemiological, preclinical, and clinical data and considers arguments for and against a role for serum uric acid in common cardiovascular disorders. It concludes that large scale trials with clinical endpoints are justified to address this important question and to define whether use of drugs such as allopurinol should be a routine part of preventative strategies.

Usefulness of combining serum uric acid and C-reactive protein for risk stratification of patients with coronary artery disease (Bezafibrate Infarction Prevention [BIP] study)

Combined assessment of serum uric acid (UA) and C-reactive protein (CRP) compared with single-marker evaluation in patients with coronary artery disease (CAD) was performed. CRP is an independent predictor of cardiac events in patients with or without CAD. Data regarding the prognostic value of UA in patients with CAD are conflicting. The primary end point (fatal or nonfatal myocardial infarction or sudden cardiac death) was related to levels of UA and CRP in 2,966 patients with CAD enrolled in the Bezafibrate Infarction Prevention trial who were followed for a mean period of 6.2 years. Primary end-point rates were directly related to increasing tertiles (from tertile 1 [T1] to tertile 3 [T3]) of UA (12.7%, 12.8%, and 17.6% respectively, p for trend <0.0001) and CRP (11.5%, 14.2%, and 17.3% respectively, p for trend <0.002). By multivariable analysis, T3 UA (>6.25 mg/dl) and T3 CRP (>5.37 mg/dl) were shown to be independently associated with a significant increase in risk for the primary end point (hazard ratio 1.30, 1.01 to 1.68, p = 0.04; hazard ratio 1.31, 1.02 to 1.69, p = 0.03, respectively). Primary end-point rates were similarly high in those patients with a combination of T3 UA and T1 CRP levels (hazard ratio 1.68, 1.05 to 2.66) or a combination of T3 CRP and T1 serum UA levels (hazard ratio 1.64, 1.04 to 2.58) or in patients with T3 of the 2 markers (hazard ratio 1.66, 1.07 to 2.59). In conclusion, combined assessment of UA and CRP levels provides incremental information for risk stratification of patients with CAD with low levels of a single marker.

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

OBJECTIVE

To examine the association of serum uric acid (SUA) with a marker of preclinical cardiovascular disease (CVD), carotid atherosclerotic plaques (PLQ), where early evidence of risk may be evident, focusing on individuals without CV risk factors.

METHODS

The National Heart, Lung, and Blood Institute Family Heart Study is a multicenter study designed to assess risk factors for heart disease. PLQ were assessed with carotid ultrasound. We conducted sex-specific logistic regression to assess the association of SUA with presence of PLQ, including analyses among persons without risk factors related to both CVD and hyperuricemia.

RESULTS

In total, 4,866 participants had both SUA and carotid ultrasound assessed (54% women, mean age 52 yrs, mean body mass index 27.6). The association of SUA with PLQ increased with increasing SUA levels, demonstrating a dose-response relation for men [OR 1.0, 1.29, 1.61, 1.75, for SUA categories < 5 (reference), 5 to < 6, 6 to < 6.8, >or= 6.8 mg/dl, respectively; p = 0.002]. Similar associations were found in men without CV risk factors. We found no relation of SUA with PLQ in women.

CONCLUSION

In this large study, SUA was associated with carotid atherosclerotic plaques in men. Results were similar in the absence of CV risk factors. These results suggest that SUA may have a pathophysiologic role in atherosclerosis in men.

Serum Levels of Uric Acid and Diabetes Mellitus Influence Survival after Surgery for Primary Hyperparathyroidism: A Prospective Cohort Study

BACKGROUND

Primary hyperparathyroidism (pHPT) is associated with an increased mortality attributable to cardiovascular disease (CVD), suggested to be alleviated by surgery. The exact mechanism of the beneficial influence of parathyroidectomy on survival is unknown. Furthermore, studies suggest that there is no increased mortality compared to the mortality rate in the general population during recent years. This study therefore investigated relative survival (RS), as well overall mortality associated with the clinical and biochemical variables in patients undergoing operation for sporadic pHPT. Furthermore, the influence of surgery on biochemical variables associated with pHPT was analyzed.

METHODS

A group of 323 patients with sporadic pHPT operated between September 1989 and July 2003 were followed from surgery over a 10-year period. The median and mean follow-up time was 69 and 70 months, respectively (range: 1-120 months). Relative survival (RS) was calculated, and the impact of clinical and biochemical variables on overall death were evaluated.

RESULTS

Postoperatively, serum levels of triglycerides and uric acid decreased. Glucose levels and glomerular filtration rate remained unchanged. A decreased RS was evident during the latter part of the 10 year follow-up period. In the multivariate Cox-analysis, diabetes mellitus (hazard ratio [HR] = 2.8, 95%; confidence interval [CI] 1.2-6.7), and the combination of an increased level of serum uric acid and cardiovascular disease (CVD) (HR = 8.6, 95%; CI 1.5-49.7) was associated with a higher mortality. The increased risk of death was evident for patients with persistently increased levels of uric acid postoperatively (HR = 4.8, 95%; CI = 1.4-16.01).

CONCLUSIONS

Patients undergoing operation for pHPT had a decreased RS during a 10-year follow-up compared to the general population. This decrease in RS is associated with diabetes mellitus and increased levels of uric acid pre-and postoperatively.

Independent association of high serum uric acid concentration with angiographically defined coronary artery disease

Epidemiological studies have shown that a high serum uric acid concentration is a risk factor for coronary artery disease (CAD). However, the issue of whether it is an independent cardiovascular risk factor or simply a marker of co-existing conditions is a matter of controversy. In the present case-controlled study, we explored the association between serum uric acid and angiographically defined CAD in middle-aged subjects (356 CAD patients and 350 healthy individuals). Serum uric acid in CAD patients was significantly higher than that in healthy individuals (359 +/- 88.7 and 289 +/- 79.3 micromol/l, respectively, p < 0.01) and remained significantly higher after adjusting for confounding factors (F = 79.77, p < 0.01). The association between uric acid and CAD was not limited to the hyperuricemic range of values, but was also found in the high-normal range (p < 0.01). An unadjusted odds ratio (OR) of 5.0 was obtained in both genders (p < 0.01). Female patients with > 50% stenosis (clinically significant CAD), regardless of the number of diseased vessels, had higher uric acid concentrations than those with < 50% stenosis even after adjusting for confounders (F = 3.79, p = 0.01). In conclusion, we have demonstrated that high serum uric acid is independently associated with CAD and that uric acid determination could be useful as one of the markers of clinically significant CAD.

Serum uric acid as a risk factor for cardiovascular and renal disease: an old controversy revived

Hyperuricemia is commonly associated with traditional risk factors such as abnormalities in glucose metabolism, dyslipidemia, and hypertension. Recent studies have revived the controversy over the role of serum uric acid as an independent prognostic factor for cardiovascular mortality. The authors review clinical and experimental evidence concerning the role of serum uric acid in the development of cardiovascular and renal damage. Results of trials suggesting that serum uric acid variations over time may have a prognostic impact are also discussed.

Uric acid and xanthine oxidase: future therapeutic targets in the prevention of cardiovascular disease?

Serum uric acid may be an independent risk factor for cardiovascular disease. This review examines this association, potential mechanisms, and explores whether strategies to reduce uric acid will improve outcomes. The recent studies of xanthine oxidase inhibition are given particular focus. Epidemiological evidence supports the theory that uric acid is an independent risk factor for cardiovascular disease. Recent studies of losartan, atorvastatin and fenofibrate suggest that uric acid reduction contributes to the risk reduction offered by these therapies. Several small studies of xanthine oxidase inhibition have shown improvements in measures of cardiovascular function of a similar magnitude to that of other proven preventative treatments. These trial data and the convincing epidemiological evidence mandate that large clinical trials of uric acid-lowering strategies are performed in patients with or at high risk of cardiovascular disease. If such approaches are shown to be effective in reducing cardiovascular events, they would represent a novel and cost-effective preventative approach.

Endothelial nitric oxide synthase G894T gene polymorphism in Chilean subjects with coronary artery disease and controls

BACKGROUND

Nitric oxide (NO) from the endothelium, produced by oxidation of l-arginine to L-citruline for the action at the endothelial nitric oxide synthase (eNOS), is considered an important atheroprotective factor. The Glu298Asp (G894T) polymorphic variant of the eNOS gene has been implicated in the development of coronary artery disease (CAD). We investigated the association between occurrence of CAD documented by angiography and the G894T polymorphism of the NOS3 gene in Chilean individuals.

METHODS

A total of 112 unrelated patients with diagnosis of CAD and 72 controls were included in this study. G894T gene polymorphism was analyzed by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP).

RESULTS

The frequency of TT homozygous genotype for G894T polymorphism was 7% in CAD patients and 1% in the control group. However, the genotype distribution and allele frequencies were not significantly different between CAD and control subjects (P>0.05). Moreover, the odds ratio for CAD associated with the T variant failed to reach statistical significance (OR=1.5; 95% CI: 0.87-2.59, P>0.05).

CONCLUSION

These findings suggest that the G894T polymorphism of the eNOS gene was not associated with CAD in Chilean individuals.

Consequences of Intrauterine Growth Restriction for the Kidney

Low birth weight due to intrauterine growth restriction is associated with various diseases in adulthood, such as hypertension, cardiovascular disease, insulin resistance and end-stage renal disease. The purpose of this review is to describe the effects of intrauterine growth restriction on the kidney. Nephrogenesis requires a fine balance of many factors that can be disturbed by intrauterine growth restriction, leading to a low nephron endowment. The compensatory hyperfiltration in the remaining nephrons results in glomerular and systemic hypertension. Hyperfiltration is attributed to several factors, including the renin-angiotensin system (RAS), insulin-like growth factor (IGF-I) and nitric oxide. Data from human and animal studies are presented, and suggest a faltering IGF-I and an inhibited RAS in intrauterine growth restriction. Hyperfiltration makes the kidney more vulnerable during additional kidney disease, and is associated with glomerular damage and kidney failure in the long run. Animal studies have provided a possible therapy with blockage of the RAS at an early stage in order to prevent the compensatory glomerular hyperfiltration, but this is far from being applicable to humans. Research is needed to further unravel the effect of intrauterine growth restriction on the kidney.

Crystal-induced arthropathies: recent investigative advances

PURPOSE OF REVIEW

To highlight recent investigations that have stimulated renewed interest in crystal-induced arthropathies.

RECENT FINDINGS

Specific diet-related and alcohol-related risks for gout have been clarified, and alternative urate-lowering treatments likely to benefit patients with difficult-to-treat gout are in development. Progress toward understanding mechanisms underlying the renal deficits defining most cases of gout includes characterization of a urate-specific renal tubule transporter explaining many aspects of renal uric acid handling and identification of mutations in the UMOD gene, resulting in altered uromodulin protein in the gout-associated disorders familial juvenile hyperuricemic nephropathy and medullary cystic kidney disease type 2. A genetic marker associated with the risk for severe allopurinol toxicity has been reported. Hyperuricemia and gout are increasing in incidence, as is complicated gout, especially among the elderly and patients with cardiovascular and renal comorbidities, organ transplants, or complex concomitant medication regimens. Asymptomatic hyperuricemia is clearly associated with hypertension, chronic kidney disease, cardiovascular disease, and the insulin resistance syndrome, and the pathogenetic significance of these associations is under intensive study. Mutation in the ANKH gene has been found among some patients with sporadic as well as familial calcium pyrophosphate deposition disease.

SUMMARY

The results of these clinical, epidemiologic, experimental, and therapeutic investigations presage advances in the management of crystal-induced arthropathies.

Hyperuricemia and Associated Diseases

After introduction of urate-lowering therapy, asympotomatic hyperuricemia was treated with allopurinol or uricosuric agents in the belief that hyperuricemia and/or gout caused chronic kidney disease. Epidemiologic studies in the 1970s, however, failed to confirm the view that hyperuricemia and gout were independent risk factors for chronic kidney disease. As a result, urate-lowering pharmacotherapy is generally not recommended at the present time in the management of asymptomatic hyperuricemia even though recent epidemiological, experimental, and clinical studies have prompted reexamination of a causal role for hyperuricemia (with or without gout) in chronic kidney disease as well as other important disorders including cardiovascular disease, hypertension, and metabolic syndrome. The issue of such a role remains unresolved and this article reviews the current status of the relationship between hyperuricemia and associated disorders.

New insights into gout epidemiology

PURPOSE OF REVIEW

The systematic study of gout dates to antiquity, to Hippocrates' initial descriptions of disease risk factors including advancing age, female menopause, and male sex. Although urate crystal diagnosis remains the gold standard for diagnosis it is impractical at a population level. Beyond crystal diagnosis, progress in gout epidemiology has been hampered by the lack of a standardized approach in defining case status.

RECENT FINDINGS

Substantial progress has been made in furthering our understanding of gout over the last few decades. Taken together, epidemiologic investigations suggest that gout frequency is on the rise worldwide. Our understanding of gout risk factors continues to expand with the recent availability of well designed prospective cohort studies from both the USA and abroad. Moreover, recent investigations have shed important insight on the complex relationships of hyperuricemia, gout, and comorbid conditions, particularly the association of serum urate levels with cardiovascular morbidity and mortality.

SUMMARY

Despite our growing understanding of the many facets of this age-old condition, current evidence continues to underscore the frequency with which gout is characterized by suboptimal care. Below we review our current knowledge of gout epidemiology with an emphasis on the association of hyperuricemia with cardiovascular comorbidity and evidence and determinants of continued suboptimal care in gout.

Adiponectin is a candidate marker of metabolic syndrome in obese children and adolescents

The aim of this study was to compare the use of several biomarkers to identify obese children and adolescents with increased metabolic risk. One hundred sixty-two Caucasian obese children and adolescents (41% males, 9-18 years old) referred to the Istituto Auxologico Italiano between 2003 and 2004 underwent an oral glucose tolerance test. Circulating levels of adiponectin (AD), plasminogen activator inhibitor 1 (PAI-1), interleukin 18 (IL-18), C-reactive protein (CRP), fibrinogen, uric acid, lipids and insulin were measured. Twenty five percent of obese children had the MS defined using World Health Organization-derived child specific criteria. MS subjects had significantly lower AD (p<0.01) and higher log-PAI-1 (p<0.001), uric acid (p<0.0001), and IL-18 (p<0.001). Subjects with AD levels </=median value had a significantly increased risk of having the MS (p<0.0001), as did subjects with uric acid and PAI-1 levels greater than the median. There was no increased risk with elevated IL-18, CRP, or fibrinogen. Hypoadiponectinemia was independently associated with the MS risk (p<0.0001). In conclusion in obese children and adolescents AD is the best predictor of MS and thus of higher cardiovascular disease risk.

Hyperuricemia as a risk factor for contrast-induced nephropathy in patients with chronic kidney disease

OBJECTIVES

Hyperuricemia as a risk factor for contrast-induced nephropathy (CIN) has not been studied.

BACKGROUND

The aim of the present study was to assess the influence of hyperuricemia on the development of CIN in patients undergoing coronary angiography.

METHODS

This was a prospective cohort study. A total of 266 patients with a mean age of 58.33 +/- 7.85 years and serum creatinine > or = 1.2 mg/dl were divided into two groups (hyperuricemic, n = 126, and normouricemic, n = 140). CIN was defined as an increase of > or = 25% in creatinine over baseline within 48 hr of angiography, and hyperuricemia as serum uric acid > or = 7 mg/dl in males and > or = 6.5 mg/dl in females.

RESULTS

CIN occurred in 15.1% of the hyperuricemic group and 2.9% of the normouricemic group (P < 0.001). Serum creatinine increased from 1.45 +/- 0.20 to 1.67 +/- 0.45 mg/dl in the hyperuricemic group and from 1.42 +/- 0.16 to 1.56 +/- 0.23 mg/dl in the normouricemic group (P < 0.001). Hyperuricemia [odds ratio (OR) 4.71; 95% confidence interval (95% CI) 1.29-17.21; P = 0.019] and a high incidence of multi-vessel coronary involvement (OR 3.59; 95% CI 1.12-11.48; P = 0.032) in the hyperuricemic group were predictors of CIN. Hypoalbuminemia (P = 0.001) and age > or = 70 years (P = 0.023) were other risk indicators of CIN. Length of hospital stay (P < 0.001) and CIN requiring renal replacement therapy (P = 0.017) were significantly higher in hyperuricemic group. Serum uric acid level > or = 7 mg/dl in males and > or = 5.9 mg/dl in females were found to be the best cut-off value for prediction of CIN.

CONCLUSION

Our data support the hypothesis that patients with hyperuricemia are at risk of developing CIN.

Genome-wide search for genes affecting serum uric acid levels: the Framingham Heart Study

Serum uric acid levels are associated with hypertension, cardiovascular disease, and renal disease. Uric acid has been shown to be heritable; however, genome-wide linkage analyses have not been reported. Genome-wide multipoint variance components linkage analyses with 401 markers spaced at approximately 10 centimorgan (cM) were conducted on 1258 subjects of the Framingham Heart Study, using the average of two serum uric acid measurements obtained in examinations 1 and 2 around 1971 and 1979. Covariates in fully adjusted model included sex, age, body mass index (BMI), serum creatinine, alcohol consumption, diabetes, diuretic treatment, and triglycerides. To investigate possible pleiotropic effects between uric acid and covariates that may have a genetic component, bivariate linkage analyses of uric acid with BMI, triglycerides, and glucose were conducted at the uric acid linkage regions. The heritability of uric acid was 0.63. The highest multipoint log-of-the-odds (LOD) score was 3.3 at 50 cM on chromosome 15 for age-sex-adjusted uric acid, but decreased to 1.5 after multivariable adjustment. Additional evidence of linkage was seen on chromosomes 2 (LOD score 1.1 at 4 cM) and 8 (LOD score 1.7 at 6 cM) for multivariable-adjusted uric acid. Pleiotropic effects were only found between uric acid and glucose and BMI at chromosomes 8 and 15 linkage locations, respectively. We have identified several novel loci linked to uric acid. We found possible pleiotropic effects between uric acid and BMI and glucose. Further research is necessary to identify the genes involved in uric acid metabolism and their roles in hypertension, cardiovascular disease, and renal disease.