Hyperuricemia and incident heart failure

Gender differences in association between uric acid and all-cause mortality in patients with chronic heart failure

Background

Elevated serum uric acid (SUA) is associated with poor prognosis in patients with cardiovascular disease, yet it is still not decided whether the role of SUA is causal or only reflects an underlying disease. The purpose of the study was to investigate if SUA was an independent predictor of 5-year all-cause mortality in a propensity score matched cohort of chronic heart failure (HF) outpatients. Furthermore, to assess whether gender or renal function modified the effect of SUA.

Methods

Patients (n = 4684) from the Norwegian Heart Failure Registry with baseline SUA were included in the study. Individuals in the highest gender-specific SUA quartile were propensity score matched 1:1 with patients in the lowest three SUA quartiles. The propensity score matching procedure created 928 pairs of patients (73.4% males, mean age 71.4 ± 11.5 years) with comparable baseline characteristics. Kaplan Meier and Cox regression analyses were used to investigate the independent effect of SUA on all-cause mortality.

Results

SUA in the highest quartile was an independent predictor of all-cause mortality in HF outpatients (hazard ratio (HR) 1.19, 95% confidence interval (CI) 1.03–1.37, p-value 0.021). Gender was found to interact the relationship between SUA and all-cause mortality (p-value for interaction 0.007). High SUA was an independent predictor of all-cause mortality in women (HR 1.65, 95% CI 1.24–2.20, p-value 0.001), but not in men (HR 1.06, 95% CI 0.89–1.25, p-value 0.527). Renal function did not influence the relationship between SUA and all-cause mortality (p-value for interaction 0.539).

Conclusions

High SUA was independently associated with inferior 5-year survival in Norwegian HF outpatients. The finding was modified by gender and high SUA was only an independent predictor of 5-year all-cause mortality in women, not in men.

Allopurinol Dose Escalation and Mortality Among Patients With Gout: A National Propensity-Matched Cohort Study

OBJECTIVE

Observational data suggest that hyperuricemia and gout are associated with increased mortality, while allopurinol use is associated with reduced mortality. In addition, the protective effect of allopurinol may be dose dependent. The aim of the current study was to determine whether allopurinol dose escalation is associated with cause-specific mortality in patients with gout.

METHODS

In this 10-year observational, active-comparator study of US Veterans with gout who initiated treatment with allopurinol, propensity score matching, Cox proportional hazards models, and competing risks regression analyses were used to assess differences in cause-specific mortality between patients whose allopurinol dose was escalated (dose escalators) and those whose allopurinol dose was not escalated or was reduced (non-escalators) over a 2-year period.

RESULTS

Among the 6,428 dose escalators and 6,428 matched non-escalators, there were 2,867 deaths during the observation period (40.4 deaths per 1,000 person-years). Dose escalators experienced an increase in all-cause mortality (hazard ratio [HR] 1.08, 95% confidence interval [95% CI] 1.01-1.17), with the effect sizes being similar for incidence of cardiovascular-related deaths (HR 1.08, 95% CI 0.97-1.21) and cancer-related deaths (HR 1.06, 95% CI 0.88-1.27), although neither reached statistical significance. Dose escalation to achieve the goal of lowering the serum urate (SU) level to <6.0 mg/dl was infrequent. At 2 years, 10% of dose escalators were receiving a final daily dose of >300 mg and 31% had achieved the SU goal. In a sensitivity analysis limited to dose escalators achieving the SU goal, there was a nonsignificant reduction of 7% in the hazard of cardiovascular-related mortality (HR 0.93, 95% CI 0.76-1.14).

CONCLUSION

This is the largest study to date to investigate the effects of allopurinol use on mortality and is the first to use a rigorous active-comparator design. Dose escalation was associated with a small (<10%) increase in all-cause mortality, thus showing that a strategy of allopurinol dose escalation, which in current real-life practice is characterized by limited dose increases, is unlikely to improve the survival of patients with gout.

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.

Serum uric acid as a potential marker for heart failure risk in men on antihypertensive treatment: The British Regional Heart Study

The role of serum uric acid (SUA) as a prognostic marker for incident heart failure (HF) in hypertensive subjects is uncertain. We have prospectively examined the relationship between SUA and incident HF in 3440 men aged 60–79 years separately in those on and not on antihypertensive treatment who were followed up for a mean period of 15 years. Men on SUA lowering drugs and those with history of HF or myocardial infarction were excluded. There were 260 incident HF cases. The men were divided into three groups of SUA concentrations/levels (< 350, 350–410 and > 410 μmol/L). Raised SUA was associated with significantly increased risk of HF in men on antihypertensive treatment (N = 949) but not in those without (N = 2491) (p = 0.003 for interaction). In men on antihypertensive treatment those with hyperuricemia (> 410 μmol/L) had the most adverse biological risk profile for HF including the highest rates of atrial fibrillation and renal dysfunction and the highest mean level of BMI, c-reactive protein and cardiac function (cardiac troponin T). Treated hypertensive men with SUA levels > 410 μmol/L showed an increase in risk of HF of more than twofold compared to those on treatment with levels < 350 μmol/L even after adjustment for lifestyle characteristics and biological risk factors [adjusted hazard ratio 2.26 (1.23,4.15)]. SUA improved prediction of HF beyond routine conventional risk factors (p = 0.02 for improvement in c-statistics). SUA as a marker of increased xanthine oxidase activity may be a useful prognostic marker for HF risk in older men on antihypertensive treatment.

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Raised serum uric acid (SUA) is associated with increased risk of heart failure in older men on antihypertensive treatment

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Treated hypertensive men with raised SUA have the most adverse risk profile for heart failure including underlying ischaemia

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Monitoring of SUA in older hypertensive patients may identify high risk patients who would benefit from further investigation

Is coffee consumption associated with a lower risk of hyperuricaemia or gout? A systematic review and meta-analysis

OBJECTIVES

To examine the associations of coffee consumption with the serum uric acid (SUA) level, hyperuricaemia (HU) and gout.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES AND STUDY ELIGIBILITY CRITERIA

A comprehensive literature search up to April 2015, using PubMed and EMBASE databases, was conducted to identify the observational researches that examined the associations of coffee consumption with the SUA level, HU and gout. The standard mean difference (SMD), OR, relative risk (RR) and their corresponding 95% CIs for the highest and the lowest categories of coffee intake were determined.

RESULTS

A total of 11 observational studies (6 cross-sectional, 3 cohort and 2 case-control studies) were included in this systematic review and meta-analysis. The combined SMD suggested that there was no significant difference between the highest and the lowest coffee intake categories in terms of the SUA level (SMD=-0.09, 95% CI -0.23 to 0.05; p=0.21). Meanwhile, the overall multivariable adjusted OR for HU showed no significant difference between the highest and the lowest coffee intake categories (OR=0.84, 95% CI 0.65 to 1.09; p=0.20). However, the overall multivariable adjusted RR for gout showed a significant inverse association between coffee consumption and the incidence of gout (RR=0.43, 95% CI 0.31 to 0.59, p<0.001).

CONCLUSIONS

Current evidences are insufficient to validate the association between coffee consumption and a lower risk of HU. Owing to the limited number of studies, the available data show that coffee consumption may be associated with a lower risk of incident gout. Further well-designed prospective researches and randomised controlled trials are therefore needed to elaborate on these issues.

Effect of Febuxostat, a Xanthine Oxidase Inhibitor, on Cardiovascular Risk in Hyperuricemic Patients with Hypertension: A Prospective, Open-label, Pilot Study

BACKGROUND AND OBJECTIVE

There is growing evidence of an association between high uric acid (UA) levels and cardiovascular disease (CVD). We hypothesized that febuxostat, a xanthine oxidase inhibitor, may be associated with suppressing the renin-angiotensin-aldosterone system (RAAS) and improving renal function in hyperurecemic patients with hypertension.

METHODS

We conducted a 6-month prospective study in which we randomized hypertensive hyperuricemic patients to either a febuxostat group (n = 30) or a control group (n = 30). The dose of febuxostat was adjusted to maintain the serum UA level at <6.0 mg/dL.

RESULTS

In the febuxostat group, the plasma renin activity (PRA), plasma aldosterone concentration (PAC), and serum UA level significantly decreased by 33 % (p = 0.0012), 14 % (p = 0.001), and 29 % (p < 0.0001), respectively. The estimated glomerular filtration rate (eGFR) significantly increased by 5.5 % (p = 0.001). Similar changes were not observed in the control group. Furthermore, a significant correlation was observed between the percent changes in the serum UA levels and the percent changes in the PRA (r = 0.277, p = 0.033), PAC (r = 0.310, p = 0.016), serum blood urea nitrogen levels (r = 0.434, p = 0.0005), serum creatinine levels (r = 0.413, p = 0.002), and eGFR (r = -0.474, p = 0.0001).

CONCLUSIONS

These results support the hypothesis that febuxostat might not only reduce serum UA levels but also suppress RAAS and improve renal function in hyperuricemic patients with hypertension, possibly leading to prevention of CVD.

Causal Assessment of Serum Urate Levels in Cardiometabolic Diseases Through a Mendelian Randomization Study

BACKGROUND

Although epidemiological studies have reported positive associations between circulating urate levels and cardiometabolic diseases, causality remains uncertain.

OBJECTIVES

Through a Mendelian randomization approach, we assessed whether serum urate levels are causally relevant in type 2 diabetes mellitus (T2DM), coronary heart disease (CHD), ischemic stroke, and heart failure (HF).

METHODS

This study investigated 28 single nucleotide polymorphisms known to regulate serum urate levels in association with various vascular and nonvascular risk factors to assess pleiotropy. To limit genetic confounding, 14 single nucleotide polymorphisms exclusively associated with serum urate levels were used in a genetic risk score to assess associations with the following cardiometabolic diseases (cases/controls): T2DM (26,488/83,964), CHD (54,501/68,275), ischemic stroke (14,779/67,312), and HF (4,526/18,400). As a positive control, this study also investigated our genetic instrument in 3,151 gout cases and 68,350 controls.

RESULTS

Serum urate levels, increased by 1 SD due to the genetic score, were not associated with T2DM, CHD, ischemic stroke, or HF. These results were in contrast with previous prospective studies that did observe increased risks of these 4 cardiometabolic diseases for an equivalent increase in circulating urate levels. However, a 1 SD increase in serum urate levels due to the genetic score was associated with increased risk of gout (odds ratio: 5.84; 95% confidence interval: 4.56 to 7.49), which was directionally consistent with previous observations.

CONCLUSIONS

Evidence from this study does not support a causal role of circulating serum urate levels in T2DM, CHD, ischemic stroke, or HF. Decreasing serum urate levels may not translate into risk reductions for cardiometabolic conditions.

Identification of nondiabetic heart failure-associated genes by bioinformatics approaches in patients with dilated ischemic cardiomyopathy

Heart failure (HF) is a common pathological condition affecting 4% of the worldwide population. However, approaches for predicting or treating nondiabetic HF (ND-HF) progression are insufficient. In the current study, the gene expression profile GSE26887 was analyzed, which contained samples from 5 healthy controls, 7 diabetes mellitus-HF patients and 12 ND-HF patients with dilated ischemic cardiomyopathy. The dataset of 5 healthy controls and 12 ND-HF patients was normalized with robust multichip average analysis and the differentially expressed genes (DEGs) were screened by unequal variance t-test and multiple-testing correction. In addition, the protein-protein interaction (PPI) network of the upregulated and downregulated genes was constructed using the Search Tool for the Retrieval of Interacting Genes/Proteins database and the Cytoscape software platform. Subsequently, gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed. A total of 122 upregulated and 133 downregulated genes were detected. The most significantly up- and downregulated genes were EIF1AY and SERPINE1, respectively. In addition, 38 and 77 nodes were obtained in the up- and downregulated PPI network. DEGs that owned the highest connectivity degree were USP9Y and UTY in the upregulated network, and CD44 in the downregulated networks, respectively. NPPA and SERPINE1 were also found to be hub genes in the PPI network. Several GO terms and pathways that were enriched by DEGs were identified, and the most significantly enriched KEGG pathways were drug metabolism and extracellular matrix-receptor interaction. In conclusion, the two DEGs, NPPA and SERPINE1, may be important in the pathogenesis of HF and may be used for the diagnosis and treatment of HF.

Serum Uric Acid and Mortality Form Cardiovascular Disease: EPOCH-JAPAN Study

AIM

To investigate the relationship between serum uric acid levels and cardiovascular disease in Asians.

METHODS

We examined the above relationship using the data of Evidence for Cardiovascular Prevention from Observational Cohorts in Japan (EPOCH-JAPAN Study). The data of 36,313 subjects (15,628 men and 20,685 women aged 35-89 years without histories of stroke, coronary heart disease, or cancer at baseline) were used for the analyses. Sex-specific hazard ratios (HRs) of mortality from cardiovascular disease were estimated according to the quintiles of serum uric acid using Cox hazard models stratified by cohorts.

RESULTS

During 441,771 person-years of follow-up, we documented 1,288 cardiovascular deaths. A J- or U-shaped relationship between serum uric acid level and cardiovascular disease mortality was observed. Compared with the lowest quintile of serum uric acid levels, the highest quintile was associated with an increased cardiovascular disease mortality in men [HR: 1.28; 95% confidence interval (CI): 1.01-1.63] and women (HR: 1.51; 95% CI: 1.14-1.99). However, there was no significant association with mortality from stroke, coronary heart disease or heart failure in both men and women.

CONCLUSION

This large pooled analysis in Japan suggested a J- or U-shaped relationship between serum uric acid levels and cardiovascular mortality. The highest quintile of serum uric acid levels was associated with increased cardiovascular disease mortality in both Japanese men and women.

Uric Acid and Cardiovascular Disease: An Update

In recent years, serum uric acid (SUA) as a determinant of cardiovascular (CV) risk has gained interest. Epidemiological, experimental and clinical data show that patients with hyperuricaemia SUA are at increased risk of cardiac, renal and vascular damage and CV events. There is now some evidence to suggest that urate-lowering treatment may reduce CV risk in this group and, thus, may represent a new strategy in risk reduction.

Comparison between procalcitonin, brain natriuretic peptide, and uric acid in children with cardiomyopathy and controls

Objective. This study was performed to determine the level of procalcitonin, Brain Natriuretic Peptide (BNP), and uric acid in children with cardiomyopathy in comparison with controls and the association with echocardiographic findings. Methods. The levels of BNP, procalcitonin, and serum uric acid were measured and the amounts of biomarkers compared with echocardiographic findings. Results. In this study mean age of participants was the same (p=0.321). The majority of echocardiographic indices in left and right heart have different means in case and controls (p<0.05). Means of BNP, procalcitonin, and uric acid were 213.814 ± 309.601, 9.326 ± 3.881, and 6.846 ± 1.814 for case group and 2.76 ± 1.013, 1.851 ± 1.466, and 3.317 ± 0.924 for control (p<0.001), respectively. In the patients group there was relationship of Ross classification with BNP (χ² = 15.845, p<0.05) and with age (χ² = 8.946, p<0.05). For uric acid and procalcitonin no significant relationships were observed. Conclusions. procalcitonin, uric acid, and BNP had significant relationship with many echocardiographic findings in participants. For patients, procalcitonin did not show correlation. The severity of illness based on the Ross classification showed significant correlation with BNP level and age in patients.

Heart failure: not a single organ disease but a multisystem syndrome

Heart failure is not simply a single organ disease; rather it is a complex multi-system clinical syndrome, with impairment of endocrine, haematological, musculoskeletal, renal, respiratory and vascular systems, which influence morbidity and mortality.

Aging, not menopause, is associated with higher prevalence of hyperuricemia among older women

OBJECTIVE

This work aims to study the associations, if any, of hyperuricemia, gout, and menopause status in the US population.

METHODS

Using multiyear data from the National Health and Nutrition Examination Survey, we performed unmatched comparisons and one to three age-matched comparisons of women aged 20 to 70 years with and without hyperuricemia (serum urate ≥6 mg/dL). Analyses were performed using survey-weighted multiple logistic regression and conditional logistic regression, respectively.

RESULTS

Overall, there were 1,477 women with hyperuricemia. Age and serum urate were significantly correlated. In unmatched analyses (n = 9,573 controls), postmenopausal women were older, were heavier, and had higher prevalence of renal impairment, hypertension, diabetes, and hyperlipidemia. In multivariable regression, after accounting for age, body mass index, glomerular filtration rate, and diuretic use, menopause was associated with hyperuricemia (odds ratio, 1.36; 95% CI, 1.05-1.76; P = 0.002). In corresponding multivariable regression using age-matched data (n = 4,431 controls), the odds ratio for menopause was 0.94 (95% CI, 0.83-1.06). Current use of hormone therapy was not associated with prevalent hyperuricemia in both unmatched and matched analyses.

CONCLUSIONS

Age is a better statistical explanation for the higher prevalence of hyperuricemia among older women than menopause status.

The relationship between body mass index and uric acid: a study on Japanese adult twins

OBJECTIVES

The present study aimed to investigate the association between body mass index (BMI) and uric acid (UA) using the twin study methodology to adjust for genetic factors.

METHODS

The association between BMI and UA was investigated in a cross-sectional study using data from both monozygotic and dizygotic twins registered at the Osaka University Center for Twin Research and the Osaka University Graduate School of Medicine. From January 2011 to March 2014, 422 individuals participated in the health examination. We measured height, weight, age, BMI, lifestyle habits (Breslow's Health Practice Index), serum UA, and serum creatinine. To investigate the association between UA and BMI with adjustment for the clustering of a twin within a pair, individual-level analyses were performed using generalized linear mixed models (GLMMs). To investigate an association with adjustment for genetic and family environmental factors, twin-pair difference values analyses were performed.

RESULTS

In all analysis, BMI was associated with UA in men and women. Using the GLMMs, standardized regression coefficients were 0.194 (95 % confidence interval: 0.016-0.373) in men and 0.186 (95 % confidence interval: 0.071-0.302) in women. Considering twin-pair difference value analyses, standardized regression coefficients were 0.333 (95 % confidence interval: 0.072-0.594) in men and 0.314 (95 % confidence interval: 0.151-0.477) in women.

CONCLUSIONS

The present study shows that BMI was significantly associated with UA, after adjusting for both genetic and familial environment factors in both men and women.

Serum uric acid is inversely proportional to estimated stroke volume and cardiac output in a large sample of pharmacologically untreated subjects: data from the Brisighella Heart Study

Serum uric acid is representative for xanthine-oxidase, the key enzyme involved in the production of uric acid, which is up-regulated in the failing heart, and may play an important role in the pathophysiologic process that leads to heart failure. In our study, we investigated the relation between stroke volume, cardiac output and serum uric acid in a large sample of overall healthy pharmacologically untreated subjects. The Brisighella Heart Study included 2,939 men and women between the ages of 14-84 without prior coronary heart disease or cerebrovascular disease who were not taking antihypertensive therapy at baseline. For this study, we selected 734 adult subjects enrolled in the last Brisighella population survey not taking antihypertensive, antidiabetic, lipid-lowering and uric acid-lowering drugs, and who were also not affected by chronic heart failure or by gout. The main predictors of cardiac functionality parameters were mean arterial pressure (MAP), HR, SUA and age (all p < 0.001), while gender, BMI, LDL-cholesterol, HDL-cholesterol, triglycerides, fasting plasma glucose, creatinine, estimated glomerular filtration rate, physical activity and smoking habit were not significantly associated (all p > 0.05). In particular, there is a strong relation between estimated cardiac output and serum uric acid (B = -0.219, p < 0.001) and between stroke volume and serum uric acid (B = -3.684, p < 0.001). These observations might have an impact on future considerations about serum uric acid as an early inexpensive marker of heart function decline in the general population.

Uricaemia and ejection fraction in elderly heart failure outpatients

BACKGROUND

Preliminary data suggest that serum uric acid (SUA) could be involved in the prognosis of chronic heart failure (HF). The aim of our study was to test the relationship between SUA and left ventricular ejection fraction (EF%) in a cohort of elderly hypertensive outpatients with chronic HF.

DESIGN

We consecutively enrolled 487 elderly outpatients (M = 59·8%; F = 40·2%; mean age: 72 ± 11 years old) affected by mild-to-moderate hypertensive and/or ischaemic HF, evaluating the relationship between SUA and EF%.

RESULTS

In an univariate analysis, SUA was inversely related with EF%: B = -4·392, 95% CI -5·427 to -3·357, P < 0·001. After adjustment for a large number of variables in a multivariate analysis, the value of EF% was best predicted by SUA (B = -3·005, 95% CI -4·386 to -1·623, P < 0·001), log brain natriuretic peptide (BNP: B = -2·341, 95% CI -3·137 to -1·248, P < 0·001) and mean arterial pressure (MAP: B = 0·241, 95% CI 0·047 to 0·435, P = 0·015). A separate analysis by estimated glomerular filtration rate (eGFR) levels confirmed the inverse relationship between SUA and EF% in patients with normal renal function. A separate analysis by sex confirmed that SUA and log BNP were significant strong predictors of EF% in men, but not in women where the best predictors were log BNP, MAP and body mass index. The predicting role of SUA was apparently independent of eGFR and use of diuretics.

CONCLUSION

Serum uric acid seems to be inversely related to EF% in male elderly patients with HF after adjustment for the several confounding factors. This observation supports a primary negative effect of SUA on left ventricular function that warrants further investigations.

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.

Uric acid and risk of heart failure: a systematic review and meta-analysis

AIMS

We aimed to perform a systematic review and meta-analysis to assess the association between serum uric acid and incident heart failure (HF)/prognosis of HF patients.

METHODS AND RESULTS

A systematic electronic literature search was conducted in Embase (Ovid SP, from 1974 to May 2013), Medline (Ovid SP, from 1946 to May 2013), and the Chinese Biomedical Literature Database (CBM, from 1978 to May 2013) to identify studies reporting on the association between serum uric acid and HF. Either a random effects model or a fixed effects model was used for pooling data. Five studies reporting on incident HF and 28 studies reporting on the adverse outcomes of HF patients were included. The results showed that hyperuricaemia was associated with an increased risk of incident HF [hazard ratio (HR) 1.65, 95% confidence interval (CI) 1.41-1.94], and the risk of all-cause mortality (HR 2.15, 95% CI 1.64-2.83), cardiovascular mortality (HR 1.45, 95% CI 1.18-1.78), and the composite of death or cardiac events (HR 1.39, 95% CI 1.18-1.63) in HF patients. For every 1 mg/dL increase in serum uric acid, the odds of development of HF increased by 19% (HR 1.19, 95% CI 1.17-1.21), and the risk of all-cause mortality and the composite endpoint in HF patients increased by 4% (HR 1.04, 95% CI 1.02-1.06) and 28% (HR 1.28, 95% CI 0.97-1.70), respectively. Subgroup analyses supported the positive association between serum uric acid and HF.

CONCLUSIONS

Elevated serum uric acid is associated with an increased risk of incident HF and adverse outcomes in HF patients.

Serum urate levels and consumption of common beverages and alcohol among Chinese in Singapore

OBJECTIVE

Western studies suggest that beverages may affect serum urate (SU) levels, but data from Asian populations are scarce. We evaluated the associations between beverages and SU levels in Singaporean Chinese.

METHODS

The study population consisted of 483 subjects ages 45-74 years from the Singapore Chinese Health Study cohort, recruited between 1993 and 1998. Lifestyle factors, medical histories, and diet were collected through in-person interviews. SU levels and other biomarkers were measured from blood collected between 1994 and 1996.

RESULTS

The mean age was 57.6 years and 44% were men. The geometric mean SU level was 321 μmoles/liter (range 157-719). Mean SU levels increased with alcohol consumption (P = 0.024 for trend). The mean SU level of daily alcohol drinkers was 42.6 μmoles/liter higher than that of nondrinkers. Similarly, increasing frequency of green tea intake was associated with rising SU levels. The highest mean SU level was observed in daily green tea drinkers (difference of 25.0 μmoles/liter) relative to nondrinkers (P = 0.009 for trend). Compared to nondrinkers, daily alcohol drinkers had an almost 5-fold increase in association with hyperuricemia (odds ratio [OR] 4.83, 95% confidence interval [95% CI] 1.10-21.23), whereas daily green tea drinkers had a 2-fold increase in association with hyperuricemia (OR 2.12, 95% CI 1.03-4.36). The present study did not show elevated levels of SU in individuals who consumed black tea, coffee, fruit juice, or soda.

CONCLUSION

Alcohol consumption increases SU levels. The finding that daily drinking of green tea is associated with hyperuricemia needs validation in future studies.

Uric acid in heart failure: a biomarker or therapeutic target?

There is a need for a cost-effective prognostic biomarker in heart failure (HF). Substantial evidence suggests that uric acid (UA) is an independent marker for adverse prognosis in acute and chronic HF of varying severity. Whether UA is a merely a marker of poor prognosis or is an active participant in disease pathogenesis is currently unknown. In the setting of HF, at least two different processes can be responsible for increased UA: increased production, which may result from oxidative stress, and decreased excretion due to renal insufficiency, which can be a consequence of cardio-renal syndrome, renal congestion, or comorbidities. While pioneer studies have raised the possibility of preventing HF through the use of UA lowering agents, namely xanthine oxidase inhibitors and uricosurics, the literature is still conflicting on whether the reduction in UA will result in a measurable clinical benefit. In this review, we examine the evidence relating UA to HF prognosis, the mechanisms that contribute to increased UA levels in HF, and future novel treatments aimed at reducing UA levels.

Is serum uric acid level an independent predictor of heart failure among patients with coronary artery disease?

BACKGROUND

Uric acid (UA) is elevated in patients with the metabolic syndrome, and there is a possible association with coronary events. Its association with future risk of heart failure (HF) is not clear. Our objective was to evaluate the association between levels of UA and risk of HF in patients with stable coronary artery disease (CAD).

HYPOTHESIS

Serum UA is associated with HF in CAD patients.

METHODS

A retrospective cohort analysis among 2939 participants of the bezafibrate infarction prevention study, assessing long-term risk of HF incidence over an 8-year of follow-up in relation to baseline UA.

RESULTS

Among patients with high levels of UA, there was a larger proportion of men, systolic hypertension, diabetes mellitus, metabolic syndrome, elevated total cholesterol, chronic renal failure, and previous coronary revascularization procedures. The rate of myocardial infarction during the follow-up was 10.9%, 10.3%, and 11.6% in the 1st, 2nd and 3rd tertiles of UA, respectively (P = 0.68). Age-adjusted hazard ratios for HF were 1.16 (95% confidence interval [CI]: 0.94-1.45) and 1.28 (95% CI: 1.04-1.59) in the 2nd and 3rd tertiles, respectively, as compared to the 1st tertile. After adjusting for multiple confounders and myocardial infarction, the hazard ratio for developing HF was 1.18 (95% CI: 0.95-1.47) and 1.25 (95% CI: 1.00-1.56) in the 2nd and 3rd tertiles of UA levels, respectively.

CONCLUSIONS

UA levels are associated with future risk of HF in patients with stable CAD, but this association is attenuated after adjusting for traditional CAD risk factors.

Effect of allopurinol on cardiovascular incidence among hypertensive nephropathy patients: the Gonryo study

BACKGROUND

The present study aimed to clarify the beneficial effect of allopurinol on cardiovascular morbidity and mortality in a cohort of hypertensive nephropathy patients with impaired kidney function.

METHODS

One hundred and seventy-eight patients diagnosed with hypertensive nephropathy and presenting with impaired kidney function (estimated glomerular filtration rate <45 mL/min/1.73 m(2)) were recruited from nephrology clinics. Oral allopurinol was prescribed in 67 of these patients. The effects of allopurinol use on the development of cardiovascular disease (i.e. ischemic heart disease, congestive heart failure, and stroke) and all-cause death was analyzed using the Cox proportional hazard model.

RESULTS

During the follow-up of 18.4 months (mean), 28 primary events occurred. Basal use of allopurinol was a significant beneficial factor (hazard ratio = 0.342, p = 0.0434, standard error = 0.53058) after adjusting for confounding factors.

CONCLUSION

The use of allopurinol in hypertensive subjects with impaired kidney function appears to be beneficial in preventing cardiovascular morbidity and all-cause mortality, indicating that this xanthine oxidase inhibitor protects the vascular system, at least in this specific group.

Effects of orange juice and hesperetin on serum paraoxonase activity and lipid profile in hyperuricemic rats

INTRODUCTION

Hypouricemic, antioxidant and xanthine oxidase inhibitory effects of orange juice and hesperetin have been already indicated. The objective of this study was to investigate the effects of orange juice and hesperetin on paraoxonase and arylesterase activity and lipid profile of hyperuricemic rats.

METHODS

Forty eight male Wistar rats were divided into 8 equal groups of healthy control, healthy+orange juice, healthy+hesperetin, healthy+allopurinol, hyperuricemic control, hyperuricemic+orange juice, hyperurice-mic+hesperetin and hyperuricemic+allopurinol. Hyperuricemia was induced using potassi-um oxonate (250 mg/kg ip). The treatments were carried out by daily gavage of 5 ml/kg orange juice, 5 mg/kg hesperetin and 5 mg/kg allopurinol for 2 weeks. Paraoxonase activi-ty in serum was measured spectrophotometrically using paraoxon and phenylacetate as substrates. Serum lipids levels were determined using enzymatic colorimetric methods.

RESULTS

Hyperuricemia-induced reduction of paraoxonase and arylesterase activity was restored after treatment with orange juice and hesperetin (p<0.05). The effect of both treatments on lipid profile was marginal and only orange juice could significantly increase the levels of HDL-C.

CONCLUSION

Supplementation of orange juice and hesperetin could restore paraoxonase and arylesterase activity in hyperuricemic rats. Orange juice could also partially improve the lipid profile. These effects could have major implications with respect to the prevention of cardiovascular disease in hyperuricemic patients. However, more studies are needed in future investigations.

Gout and the risk for incident heart failure and systolic dysfunction

OBJECTIVE

To test the hypothesis that gouty arthritis (gout) is a risk factor for incidence of heart failure and for echocardiographic measures signifying subclinical heart failure.

DESIGN

Post-hoc, longitudinal and cross-sectional analyses of a prospective cohort study where data were collected in 4-year intervals since 1971.

SETTINGS

The population-based Framingham Offspring Study.

PARTICIPANTS

4989 adults (mean age 36 years, 52% women) free of clinical heart failure at baseline.

OUTCOME MEASURES

Incident heart failure, echocardiographic measures of left ventricular systolic dysfunction, dilatation and hypertrophy.

RESULTS

Participants with gout (n=228) had two to three times higher incidence of clinical heart failure and echocardiographic measures of systolic dysfunction compared with those without. In Cox regression analyses, gout was associated with an adjusted HR of 1.74 (95% CI 1.03 to 2.93) for incident heart failure and RRs of 3.70 (95% CI 1.68 to 8.16) for abnormally low left ventricular ejection fraction and of 3.60 (95% CI 1.80 to 7.72) for global left ventricle systolic dysfunction. These risk relationships were consistently observed in all clinical subgroups. Overall, participants with gout had greater mortality than those without (adjusted HR 1.58, 95% CI 1.40 to 1.78). Mortality was elevated in subgroup of patients with gout and heart failure (adjusted HR 1.50, 95% CI 1.30 to 1.73) compared to those with heart failure but without gout.

CONCLUSION

Gout is associated with increased risk for clinical heart failure, subclinical measures of systolic dysfunction and mortality.

Hyperuricemia and the echocardiographic measures of myocardial dysfunction

Few studies have investigated the association between hyperuricemia and subclinical myocardial dysfunction. The authors analyzed the relationship between serum uric acid and subclinical markers of heart failure in participants in the Framingham Offspring Cohort (N=2169, mean age 57.3 years, 55.4% women). Cardiac dysfunction was assessed through echocardiographic measurements of left ventricular (LV) mass and thickness, end-diastolic LV thickness, and LV fractional shortening at the sixth visit, approximately 24 years after study onset. Participants in the highest serum uric acid quartile (≥ 6.2 mg/dL serum uric acid) had a significantly greater frequency of echocardiographic abnormalities compared with those in the lowest quartile (<4.3 mg/dL). Those in the highest quartile had multivariable-adjusted odds ratios of 9.013 (95% confidence interval, 2.051-39.604) for abnormal LV ejection fraction and 4.584 (95% confidence interval, 1.951-10.768) for LV systolic dysfunction compared with those in the lowest quartile. Hyperuricemia in young adults can be a marker for subsequent heart failure.

Reactive oxygen species in cardiovascular disease

Based on the "free radical theory" of disease, researchers have been trying to elucidate the role of oxidative stress from free radicals in cardiovascular disease. Considerable data indicate that reactive oxygen species and oxidative stress are important features of cardiovascular diseases including atherosclerosis, hypertension, and congestive heart failure. However, blanket strategies with antioxidants to ameliorate cardiovascular disease have not generally yielded favorable results. However, our understanding of reactive oxygen species has evolved to the point at which we now realize these species have important roles in physiology as well as pathophysiology. Thus, it is overly simplistic to assume a general antioxidant strategy will yield specific effects on cardiovascular disease. Indeed, there are several sources of reactive oxygen species that are known to be active in the cardiovascular system. This review addresses our understanding of reactive oxygen species sources in cardiovascular disease and both animal and human data defining how reactive oxygen species contribute to physiology and pathology.