Hyperuricemia and Associated Diseases

A paper based microfluidic device for easy detection of uric acid using positively charged gold nanoparticles

A paper based microfluidic device is fabricated that can rapidly detect very low concentrations of uric acid (UA) using 3,5,3',5'-tetramethyl benzidine (TMB), H2O2 and positively charged gold nanoparticles ((+)AuNPs). In the presence of (+)AuNPs, H2O2 reacts with TMB to produce a bluish-green colour which becomes colourless on reaction with UA. This colorimetric method can detect as low as 8.1 ppm of UA within <20 minutes on white filter paper. This technique provides an alternative way for UA detection.

Gout and Risk of Myocardial Infarction: A Systematic Review and Meta-Analysis of Cohort Studies

Introduction

A high incidence of myocardial infarction among patients with gout has been suggested by several observational studies. We performed a meta-analysis to evaluate the association between gout and the risk of myocardial infarction.

Materials and Methods

The PubMed and Embase databases were searched from inception to October 2014 for cohort studies that evaluating the association between gout and the risk of myocardial infarction. Summary estimates were derived using a random-effects model and reported as relative risks (RRs) with 95% confidence intervals (CIs).

Results

Five studies involving 8,656,413 participants with a total of 1000 MI events were included. Overall, gout was associated with an increased risk of myocardial infarction (RR 1.45; 95% CI, 1.19–1.75; p<0.001), and the association referred to non-fatal myocardial infarction (RR 1.29; 95% CI, 1.19–1.39; p <0.001) but not fatal myocardial infarction (RR 1.11; 95% CI, 0.96–1.28; p = 0.174). The increased risk was observed in both women (RR 1.62; 95% CI, 1.18–2.21; p = 0.003) and men (RR 1.45; 95% CI, 1.21–1.74; p <0.001). Stratified analysis revealed a gradual increase in myocardial infarction risk with a younger age of gout onset (age 20–44 years old (RR 2.82; 95% CI, 1.38–5.79; p = 0.05); 45–69 years old (RR 1.85; 95% CI, 1.22–2.82; p = 0.04); ≥70 years old (RR 1.52; 95% CI, 1.22–1.88; p <0.001)).

Conclusion

This meta-analysis suggests that patients with gout have an increased risk of myocardial infarction.

Pharmacokinetics, pharmacodynamics, and safety of lesinurad, a selective uric acid reabsorption inhibitor, in healthy adult males

Lesinurad is a selective uric acid reabsorption inhibitor under investigation for the treatment of gout. Single and multiple ascending dose studies were conducted to evaluate pharmacokinetics, pharmacodynamics, and safety of lesinurad in healthy males. Lesinurad was administered as an oral solution between 5 mg and 600 mg (single ascending dose; N=34) and as an oral solution or immediate-release capsules once daily (qday) between 100 mg and 400 mg for 10 days under fasted or fed condition (multiple ascending dose; N=32). Following single doses of lesinurad solution, absorption was rapid and exposure (maximum observed plasma concentration and area under the plasma concentration–time curve) increased in a dose-proportional manner. Following multiple qday doses, there was no apparent accumulation of lesinurad. Urinary excretion of unchanged lesinurad was generally between 30% and 40% of dose. Increases in urinary excretion of uric acid and reductions in serum uric acid correlated with dose. Following 400 mg qday dosing, serum uric acid reduction was 35% at 24 hours post-dose, supporting qday dosing. A relative bioavailability study in healthy males (N=8) indicated a nearly identical pharmacokinetic profile following dosing of tablets or capsules. Lesinurad was generally safe and well tolerated.

Wide expression of type I Na+-phosphate cotransporter 3 (NPT3/SLC17A2), a membrane potential-driven organic anion transporter

Membrane potential (Δψ)-driven and Cl(-)-dependent organic anion transport is a primary function of the solute carrier family 17 (SLC17) transporter family. Although the transport substrates and physiological relevance of the major members are well understood, SLC17A2 protein known to be Na(+)-phosphate cotransporter 3 (NPT3) is far less well characterized. In the present study, we investigated the transport properties and expression patterns of mouse SLC17A2 protein (mNPT3). Proteoliposomes containing the purified mNPT3 protein took up radiolabeled p-aminohippuric acid (PAH) in a Δψ- and Cl(-)-dependent manner. The mNPT3-mediated PAH uptake was inhibited by 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDs) and Evans blue, common inhibitors of SLC17 family members. The PAH uptake was also inhibited by various anionic compounds, such as hydrophilic nonsteroidal anti-inflammatory drugs (NSAIDs) and urate. Consistent with these observations, the proteoliposome took up radiolabeled urate in a Δψ- and Cl(-)-dependent manner. Immunohistochemistry with specific antibodies against mNPT3 combined with RT-PCR revealed that mNPT3 is present in various tissues, including the hepatic bile duct, luminal membranes of the renal urinary tubules, maternal side of syncytiotrophoblast in the placenta, apical membrane of follicle cells in the thyroid, bronchiole epithelial cells in the lungs, and astrocytes around blood vessels in the cerebrum. These results suggested that mNPT3 is a polyspecific organic anion transporter that is involved in circulation of urate throughout the body.

Traditional Uighur Medicine Karapxa decoction, inhibits liver xanthine oxidase and reduces serum uric acid concentrations in hyperuricemic mice and scavenges free radicals in vitro

Background

Karapxa decoction (KD) is a Traditional Uighur Medicine used for hepatitis, cholecystitis, gastralgia, oedema, gout and arthralgia. Because of its purported effect in gout, its effects were tested in hyperuricemic mice models induced by yeast extract paste or potassium oxonate, as well as its capacity to scavenge free radicals in vitro.

Methods

Hyperuricemia was induced in mice by yeast extract paste or potassium oxonate. KD was given orally for 14 days at 200, 400 and 800 mg/kg/day, with Allopurinol 10 mg/kg/day as positive control. Serum uric acid (UA), and liver xanthine oxidase activity (XO) were measured. Scavenging activity of KD on 1, 1-diphenyl-2-picrylhydrazyl radicals (DPP•), nitric oxide (•NO), superoxide (O₂•-), efficiency against lipid peroxidation, and XO inhibition were determined in vitro.

Results

KD inhibited liver XO activity and reduced serum uric acid in hyperuricemic mice. KD also showed noticeable antioxidant activity, scavenging free radicals (DPP•, •NO and O₂•-). It was effective against lipid peroxidation and inhibited XO in vitro.

Conclusions

This study supports the traditional use of Karapxa decoction to treat hyperuricemia and gout.

Prevalence of gout with comorbidity aggregations in southern Taiwan

OBJECTIVE

Comorbidity is an important concern for chronic gout patients. We evaluated the relationship between comorbidity profiles and gout in Taiwan aborigines and Taiwanese Han.

METHODS

We used the claims data from the Taiwan national health insurance database for 2004 to 2006. Physician-diagnosed gout and comorbidities were coded using the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM). Total sampling from Pingtung County of southern Taiwan included 37,482 aborigines (gout cases, n=3906 and controls, n=33,576) and 37,451 Han (gout cases, n=1115 and controls, n=36,336).

RESULTS

In 2006, the gout prevalences were 10.42% and 2.98% (prevalence ratio [PR]=3.50) in the aborigines and Han general populations, respectively. The prevalences of uric acid nephrolithiasis and tophi were higher in aborigines (0.42% and 0.30%, respectively) than in Han (0.09% and 0.04%, respectively). When stratified by comorbidity status, the prevalences of gout were 4.49% and 27.34% in aborigines and 1.52% and 9.44% in Han (approximate PR=3.00). Similarly, the prevalence ratios of gout in the comorbidity group, compared with the non-comorbidity group, were 6.09 in aborigines and 6.23 in Han. Multivariate odds ratios [ORs] showed that hypercholesterolemia, hyperglyceridemia, essential hypertension and renal insufficiency were the common comorbidities of gout (OR≥1.63); heart failure exerted a significant effect only in aborigines (OR=1.55). For five comorbidity factors, patients with multiple comorbidities had higher gout prevalence (maximum OR=12.90).

CONCLUSION

Gout prevalence was higher in aborigines, both with and without comorbidities, than in Han. The comorbid diseases and comorbidity aggregations showed a substantial association with gout occurrence in both ethnicities.

Is hyperuricemia an independent risk factor for new-onset chronic kidney disease?: A systematic review and meta-analysis based on observational cohort studies

BACKGROUND

Hyperuricemia has been reported to be associated with chronic kidney disease (CKD). However whether an elevated serum uric acid level is an independent risk factor for new-onset CKD remained controversial.

METHODS

A systematic review and meta-analysis using a literature search of online databases including PubMed, Embase, Ovid and ISI Web/Web of Science was conducted. Summary adjusted odds ratios with corresponding 95% confidence intervals (95% CI) were calculated to evaluate the risk estimates of hyperuricemia for new-onset CKD.

RESULTS

Thirteen studies containing 190,718 participants were included. A significant positive association was found between elevated serum uric acid levels and new-onset CKD at follow-up (summary OR, 1.15; 95% CI, 1.05-1.25). Hyperuricemia was found be an independent predictor for the development of newly diagnosed CKD in non-CKD patients (summary OR, 2.35; 95% CI, 1.59-3.46). This association increased with increasing length of follow-up. No significant differences were found for risk estimates of the associations between elevated serum uric acid levels and developing CKD between males and females.

CONCLUSIONS

With long-term follow-up of non-CKD individuals, elevated serum uric acid levels showed an increased risk for the development of chronic renal dysfunction.

Optimization of pH values to formulate the bireagent kit for serum uric acid assay

A new formulation of the bireagent kit for serum uric acid assay was developed based on the effects of pH on enzyme stability. At 4 °C, half-lives of uricases from Bacillus fastidious and Arthrobacter globiforms were longer than 15 months at pH 9.2, but became shorter at pH below 8.0; half-lives of ascorbate oxidase and peroxidase were comparable at pH 6.5 and 7.0, but became much shorter at pH higher than 7.4. In the new formulation of the bireagent kit, Reagent A contained peroxidase, 4-aminoantipyrine, and ascorbate oxidase in 50 mM phosphate buffer at pH 6.5; Reagent B contained B. fastidious or A. globiforms uricase in 50 mM sodium borate buffer at pH 9.2; Reagents A and B were mixed at 4:1 to produce a final pH from 7.2 to 7.6 for developing a stable color. The new bireagent kit consumed smaller quantities of three enzymes for the same shelf life. With the new bireagent kit, there were linear responses of absorbance at 546 nm to uric acid up to 34 mM in reaction mixtures and a good correlation of uric acid levels in clinical sera with those by a commercial kit, but stronger resistance to ascorbate. Therefore, the new formulation was advantageous.

Evaluation of the Antihyperuricemic Activity of Phytochemicals from Davallia formosana by Enzyme Assay and Hyperuricemic Mice Model

Abnormal serum urate levels are recognized as a critical factor in the progression of several chronic diseases. To evaluate the antihyperuricemic effect of Davallia formosana, the inhibitory activities of 15 isolated phytochemicals, including five novel compounds of 6,8-dihydroxychromone-7-C-β-d-glucopyranoside (1), 6,8,3′,4′-tetrahydroxyflavanone-7-C-β-d-glucopyranoside (2), 6,8,4′-trihydroxyflavanone-7-C-β-d-glucopyranoside (3), 8-(2-pyrrolidinone-5-yl)-catechin-3-O-β-d-allopyranoside (4), and epiphyllocoumarin-3-O-β-d-allopyranoside (5), were examined against xanthine oxidase (XOD) and in a potassium oxonate-(PTO-) induced acute hyperuricemic mice model. The results indicated that compounds 3 and 5 significantly inhibited XOD activity in vitro and reduced serum uric acid levels in vivo. This is the first report providing new insights into the antihyperuricemic activities of flavonoid glycosides which can possibly be developed into potential hypouricemic agents.

High serum ferritin levels increase the risk of hyperuricemia: a cross-sectional and longitudinal study

BACKGROUND/AIMS

To examine the cross-sectional and longitudinal associations of serum ferritin levels with hyperuricemia.

METHODS

A cross-sectional and subsequently prospective study was performed among the employees of Zhenhai Refining and Chemical Company, Ningbo, China. In a cross-sectional study, the association between serum ferritin levels and the prevalence of hyperuricemia was analyzed. Subjects who were free of hyperuricemia at baseline were followed up annually to explore the prospective association between serum ferritin levels and hyperuricemia incidence.

RESULTS

Of the 10,074 subjects enrolled at baseline, 1,731 (17.18%) fulfilled the diagnostic criteria of hyperuricemia. Subjects with hyperuricemia presented significantly higher serum ferritin levels, and the levels were positively correlated with the prevalence of hyperuricemia. During a total of 22,367 person-years of follow-up, 502 subjects developed hyperuricemia. The overall incidence of hyperuricemia for 1,000 person-years of follow-up was 22.4, ranging from 17.6 in subjects with baseline serum ferritin levels in the first quintile to 19.2, 21.7, 23.9, and 30.7 in subjects in quintiles 2, 3, 4, and 5, respectively (p for trend < 0.001). Cox regression analyses showed that serum ferritin levels were positively associated with the risk of incident hyperuricemia.

CONCLUSIONS

Our cross-sectional and longitudinal results indicate that high serum ferritin levels increase the risk of hyperuricemia.

Betaine reduces serum uric acid levels and improves kidney function in hyperuricemic mice

Betaine as a dietary alkaloid has attracted the attention of patients with kidney diseases. This study aimed to investigate the effects of betaine on serum uric acid levels and kidney function, and explore their underlying mechanisms in potassium oxonate-induced hyperuricemic mice. Betaine at 5, 10, 20, and 40 mg/kg was orally administered to hyperuricemic mice for 7 days and found to significantly reduce serum uric acid levels and increase fractional excretion of uric acid in hyperuricemic mice in a dose-dependent manner. It effectively restored renal protein level alterations of urate transport-related molecular proteins urate transporter 1, glucose transporter 9, organic anion transporter 1, and ATP-binding cassette subfamily G member 2 in this model, possibly resulting in the enhancement of kidney urate excretion. Moreover, betaine reduced serum creatinine and blood urea nitrogen levels and affected urinary levels of beta-2-microglobulin and N-acetyl-beta-D-glucosaminidase as well as upregulated renal protein levels of organic cation/carnitine transporters OCT1, OCTN1, and OCTN2, resulting in kidney function improvement in hyperuricemic mice. The findings from this study provide evidence that betaine has anti-hyperuricemic and nephroprotective actions by regulating protein levels of these renal organic ion transporters in hyperuricemic mice.

Diabetes and gout: efficacy and safety of febuxostat and allopurinol

AIM

Assess influences of demographics and co-morbidities of gout patients with or without diabetes on safety and efficacy of urate-lowering agents.

METHODS

Post-hoc analysis of 312 diabetic and 1957 non-diabetic gout patients [baseline serum urate levels (sUA) ≥8.0 mg/dl] enrolled in a 6-month randomized controlled trial comparing urate-lowering efficacy (ULE) and safety of daily xanthine oxidase inhibitors (XOIs) febuxostat (40 mg or 80 mg) and allopurinol (200 mg or 300 mg). We compared baseline demographic, gout and co-morbid characteristics, ULE, and safety of XOI treatment in diabetic and non-diabetic gout patients. ULE was measured by the proportion of diabetic and non-diabetic patients in each treatment group achieving final visit sUA < 6.0 mg/dl. Safety was monitored throughout the trial.

RESULTS

Diabetic gout patients were older, more frequently female, and had longer gout duration. Co-morbidities were more frequent among diabetic patients: cardiovascular disease; impaired renal function; hyperlipidemia; and obesity (body mass index >30 kg/m²) (p < 0.001 for all comparisons). Febuxostat 80 mg ULE exceeded that of febuxostat 40 mg or allopurinol (p < 0.050) at all levels of renal function, achieving sUA goal range in the majority of diabetic and non-diabetic patients. Diabetics and non-diabetics reported self-limiting diarrhoea and URIs as the most common adverse events.

CONCLUSIONS

Despite higher co-morbidity rates in diabetic patients, febuxostat and allopurinol were safe in both groups at the doses tested. Febuxostat 80 mg achieved sUA <6.0 mg/dl more often than febuxostat 40 mg or allopurinol at commonly prescribed doses.

The effect of gout on health-related quality of life, work productivity, resource use and clinical outcomes among patients with hypertension

Although gout has been found to be associated with health-related quality of life (HRQoL), few studies have examined the burden of gout in the presence of concomitant cardiometabolic conditions. The present study evaluated the effect of gout on HRQoL and work productivity among patients with hypertension. Data from the 2010 National Health and Wellness Survey were obtained for respondents ≥18 years of age who had self-reported, physician-diagnosed hypertension or blood pressure levels ≥140/90 mmHg (≥130/80 mmHg for those with physician-diagnosed diabetes or chronic kidney disease). Bivariate analysis was used to evaluate differences between patients with and without self-reported comorbid gout. Generalized linear models were used to evaluate differences in productivity (using the Work Productivity and Activity Impairment scale) and HRQoL (using the physical component summary [PCS], mental component summary and health utilities from the SF-12v2 health survey). As uric acid levels may influence other organ systems, core modeling did not include comorbidities other than osteoarthritis and depression as covariates. Sensitivity analyses were controlled for the Charlson comorbidity index. A total of 22,686 patients with self-reported hypertension met study eligibility requirements. Of these, 4.51% reported having gout. These patients were older, more likely to be male and have insurance through Veteran Affairs (all p-values < 0.05). Patients with comorbid gout reported lower levels of mental component summary scores (47.25 vs 48.93), PCS scores (39.06 vs 43.78) and health utilities (0.68 vs 0.73; all p-values < 0.05). For both PCS and health utilities, differences between groups exceeded clinically meaningful cutoffs. Sensitivity analyses conducted on PCS and health utilities uncovered slightly smaller, but statistically significant and clinically meaningful, effects (p-values < 0.05). The effect of gout on overall work impairment (23.33 vs 17.40% with and without comorbid gout, respectively) remained after controlling for the Charlson comorbidity index. Significantly greater impairment in daily activities (38.96 vs 28.32%; p < 0.05) was also observed among patients with comorbid gout. Results demonstrate that gout has significant and clinically meaningful impact on work productivity, physical HRQoL and utilities independent of other health conditions.

Effects of Uric Acid on Lipid Levels in CKD Patients in a Randomized Controlled Trial

Background

Few studies have been conducted that compared lipid levels and uric acid in CKD or End-Stage Renal Disease (ESRD) patients with most using animal models. The purpose of the study was to explore effects on lipids while controlling uric acid levels in CKD patients.

Methods

Twenty-four CKD patients (N = 24) volunteered to participate in this study. The study was conducted using a double-blind, randomized, placebo controlled experimental protocol. The experimental group was prescribed 300 mg of allopurinol PO daily by their treating physician and followed prospectively for 8-weeks. The control group consumed a similar pill once a day for 8-weeks.

Results

ANCOVA revealed significant differences in total cholesterol (P = 0.009) and Apo B (P = 0.006) with lower levels in the allopurinol group. A trend emerged with LDL (P = 0.052) with lower levels in the allopurinol group. No significant differences were discovered in triglycerides (P = 0.403), HDL (P = 0.762) and total Cholesterol/HDL Ratio (P = 0.455).

Conclusions

After statistically controlling for compliance and inflammation significant differences between groups were observed for total cholesterol and Apo B. In both instances the allopurinol group had lower concentrations than the placebo group. Similarly, a trend was observed in LDL with the allopurinol group having lower concentrations than the placebo group.

Polymorphisms in the NLRP3 gene and risk of primary gouty arthritis

The aim of the present study was to investigate the association between genetic variants in 17 tagSNPs of the NLRP3 gene and the susceptibility to primary gouty arthritis. A genotype-phenotype analysis of 480 primary gout and 480 control patients was performed. Samples from all the patients were collected from The Affiliated Hospital of Medical College (Qingdao, China). Seventeen tagSNPs of the NLRP3 gene were amplified using polymerase chain reaction (PCR) and MassARRAY technology was used for single nucleotide polymorphism (SNP) genotyping. The genetic frequency of rs7512998 was significantly different between the gout and control patients (P<0.05), whereas no significant differences were identified for the remaining SNPs. The 17 SNPs conformed to the Hardy-Weinberg equilibrium (HWE) in the control group (P>0.05). The haplotype association among the 17 SNPs of the NLRP3 gene indicated that no individual SNP was significantly associated with primary gouty arthritis. CTATCAGCGCCCAGTGC was the most common haplotype in the case and control groups, with a frequency of 0.224 and 0.243, respectively. However, the odds ratios (ORs) of the 8 haplotypes were not identified to be significantly associated with gouty arthritis (P>0.05 for all the 8 haplotypes). To the best of our knowledge, this is the first study to investigate the association between SNPs of the NLRP3 gene and the risk of primary gouty arthritis, although no significant association was identified. Further clinical studies and functional analysis are required to explore the potential associations between NLRP3 gene polymorphisms and the risk of primary gouty arthritis.

A Na+-phosphate cotransporter homologue (SLC17A4 protein) is an intestinal organic anion exporter

The SLC17 anion transporter family comprises nine members that transport various organic anions in membrane potential (Δψ)- and Cl−-dependent manners. Although the transport substrates and physiological relevance of the majority of the members have already been determined, little is known about SLC17A4 proteins known to be Na+-phosphate cotransporter homologue (NPT homologue). In the present study, we investigated the expression and transport properties of human SLC17A4 protein. Using specific antibodies, we found that a human NPT homologue is specifically expressed and present in the intestinal brush border membrane. Proteoliposomes containing the purified protein took up radiolabeled p-aminohippuric acid (PAH) in a Cl−-dependent manner at the expense of an electrochemical gradient of protons, especially Δψ, across the membrane. The Δψ- and Cl−-dependent PAH uptake was inhibited by diisothiocyanostilbene-2,2′-disulfonic acid and Evans blue, common inhibitors of SLC17 family members. cis-Inhibition studies revealed that various anionic compounds, such as hydrophilic nonsteroidal anti-inflammatory drugs, pravastatin, and urate inhibited the PAH uptake. Proteoliposomes took up radiolabeled urate, with the uptake having properties similar to those of PAH uptake. These results strongly suggested that the human NPT homologue acts as a polyspecific organic anion exporter in the intestines. Since SLC17A1 protein (NPT1) and SLC17A3 protein (NPT4) are responsible for renal urate extrusion, our results reveal the possible involvement of a NPT homologue in urate extrusion from the intestinal duct.

The effects of fructose intake on serum uric acid vary among controlled dietary trials

Hyperuricemia is linked to gout and features of metabolic syndrome. There is concern that dietary fructose may increase uric acid concentrations. To assess the effects of fructose on serum uric acid concentrations in people with and without diabetes, we conducted a systematic review and meta-analysis of controlled feeding trials. We searched MEDLINE, EMBASE, and the Cochrane Library for relevant trials (through August 19, 2011). Analyses included all controlled feeding trials ≥ 7 d investigating the effect of fructose feeding on uric acid under isocaloric conditions, where fructose was isocalorically exchanged with other carbohydrate, or hypercaloric conditions, and where a control diet was supplemented with excess energy from fructose. Data were aggregated by the generic inverse variance method using random effects models and expressed as mean difference (MD) with 95% CI. Heterogeneity was assessed by the Q statistic and quantified by I(2). A total of 21 trials in 425 participants met the eligibility criteria. Isocaloric exchange of fructose for other carbohydrate did not affect serum uric acid in diabetic and nondiabetic participants [MD = 0.56 μmol/L (95% CI: -6.62, 7.74)], with no evidence of inter-study heterogeneity. Hypercaloric supplementation of control diets with fructose (+35% excess energy) at extreme doses (213-219 g/d) significantly increased serum uric acid compared with the control diets alone in nondiabetic participants [MD = 31.0 mmol/L (95% CI: 15.4, 46.5)] with no evidence of heterogeneity. Confounding from excess energy cannot be ruled out in the hypercaloric trials. These analyses do not support a uric acid-increasing effect of isocaloric fructose intake in nondiabetic and diabetic participants. Hypercaloric fructose intake may, however, increase uric acid concentrations. The effect of the interaction of energy and fructose remains unclear. Larger, well-designed trials of fructose feeding at "real world" doses are needed.

Increased expression of SLC2A9 decreases urate excretion from the kidney

Urate is the final metabolite of purine in humans. Renal urate handling is clinically important because under-reabsorption or underexcretion causes hypouricemia or hyperuricemia, respectively. We have identified a urate-anion exchanger, URAT1, localized at the apical side and a voltage-driven urate efflux transporter, URATv1, expressed at the basolateral side of the renal proximal tubules. URAT1 and URATv1 are vital to renal urate reabsorption because the experimental data have illustrated that functional loss of these transporter proteins affords hypouricemia. While mutations affording enhanced function via these transporter proteins on urate handling is unknown, we have constructed kidney-specific transgenic (Tg) mice for URAT1 or URATv1 to investigate this problem. In our study, each transgene was under the control of the mouse URAT1 promoter so that transgene expression was directed to the kidney. Plasma urate concentrations in URAT1 and URATv1 Tg mice were not significantly different from that in wild-type (WT) mice. Urate excretion in URAT1 Tg mice was similar to that in WT mice, while URATv1 Tg mice excreted more urate compared with WT. Our results suggest that hyperfunctioning URATv1 in the kidney can lead to increased urate reabsorption and may contribute to the development of hyperuricemia.

Human uric acid transporter 1 (hURAT1): an inhibitor structure-activity relationship (SAR) study

The current study describes the chemical synthesis of a series of (2-ethylbenzofuran-3-yl)(substituted-phenyl)methanone compounds and their subsequent in vitro testing via oocytes expressing hURAT1. The experimental data support the notion that a potent hURAT1 inhibitor requires an anion (i.e., a formal negative charge) to interact with the positively charged hURAT1 binding pocket. An anion appears to be a primary requirement in order to be a hURAT1 substrate (i.e., urate) or inhibitor. We discuss the inhibitor structure-activity relationship and how electronically donating or withdrawing groups attached to the B-ring can decrease or increase inhibitory potency, respectively.

[The epidemiology and genetic of gout]

Gout affects 1-2% of adults in developed countries, where it is the most common inflammatory arthritis in men. Epidemiological data are consistent with a rise in the prevalence of gout. Diet and genetic predisposition seem to be the main causal factors of primary gout. Gout and hyperuricaemia are associated with hypertension, diabetes mellitus, metabolic syndrome, and renal and cardiovascular diseases. Genetic studies have found that variants of GLUT9 and ABCG2 were associated with urate levels.

Developing potent human uric acid transporter 1 (hURAT1) inhibitors

The kidneys are a vital organ in the human body. They serve several purposes including homeostatic functions such as regulating extracellular fluid volume and maintaining acid-base and electrolyte balance and are essential regarding the excretion of metabolic waste. Furthermore, the kidneys play an important role in uric acid secretion/reabsorption. Abnormalities associated with kidney transporters have been associated with various diseases, such as gout. The current study utilized Xenopus oocytes expressing human uric acid transporter 1 (hURAT1; SLC22A12) as an in vitro method to investigate novel compounds and their ability to inhibit (14)C-uric acid uptake via hURAT1. We have prepared and tested a series of 2-ethyl-benzofuran compounds and probed the hURAT1 in vitro inhibitor structure-activity relationship. As compared to dimethoxy analogues, monophenols formed on the C ring showed the best in vitro inhibitory potential. Compounds with submicromolar (i.e., IC(50) < 1000 nM) inhibitors were prepared by brominating the corresponding phenols to produce compounds with potent uricosuric activity.

Effect of hydrochlorothiazide on the pharmacokinetics and pharmacodynamics of febuxostat, a non-purine selective inhibitor of xanthine oxidase

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

Hyperuricaemia and gout frequently coexist with cardiovascular disorders such as hypertension and heart failure. The use of diuretics has been re-established as a first-line treatment for patients with hypertension and the effects of diuretics on serum uric acid may diminish the urate-lowering effects of febuxostat, a novel, potent, non-purine selective inhibitor of xanthine oxidase.

WHAT THIS STUDY ADDS

Co-administration of febuxostat 80 mg and hydrochlorothiazide 50 mg had no effect on the pharmacokinetics and did not have a clinically significant effect on the pharmacodynamics of febuxostat. Dose adjustment for febuxostat is not necessary when it is administered with hydrochlorothiazide.

AIM

This study examined the effect of co-administration of febuxostat, an investigational urate lowering therapy, and hydrochlorothiazide on the pharmacokinetics and pharmacodynamics of febuxostat.

METHODS

Healthy subjects (36 healthy men and women) received single doses of febuxostat 80 mg alone and febuxostat 80 mg + hydrochlorothiazide 50 mg, separated by 7 days in an open-label, randomized, crossover fashion. Plasma concentrations of febuxostat and urinary and serum concentrations of uric acid were assessed.

RESULTS

Mean febuxostat C(max), AUC((0-t)), AUC((0-infinity)), t(1/2,z), CL/F and V(ss)/F values for regimens co-administration/febuxostat alone were 2.9/2.9 microg ml(-1), 9.3/9.1 microg ml(-1) h, 9.6/9.3 microg ml(-1) h, 6.5/6.1 h, 8.8/9.3 l h(-1) and 45/44 l, respectively. Geometric mean ratios (co-administration : febuxostat alone) and their 90% confidence intervals for febuxostat plasma C(max), AUC((0-t)), and AUC((0-infinity)) were 1.00 (0.86, 1.17), 1.03 (0.98, 1.09), and 1.04 (0.98, 1.10), respectively; all of the 90% CIs were within the no effect range of 0.8 to 1.25. Serum uric acid C(mean,24h), C(mean,48h) and CL(R) for both regimens co-administration/febuxostat alone were 216/203 micromol l(-1), 218/202 micromol l(-1) and 9.1/10.1 ml min(-1), respectively. Although serum uric acid C(mean,24h) and C(mean,48h) values were higher and CL(R) values lower after co-administration compared with dosing of febuxostat alone, with the differences being statistically significant (P < 0.003), none of the differences (6.5%-9.5%) was considered clinically significant.

CONCLUSION

Dose adjustment for febuxostat is not necessary when it is administered with hydrochlorothiazide.

A 'complexity' of urate transporters

Genetic variation in the SLC2A9 gene is a new genetic risk factor for low fractional excretion of uric acid, hyperuricemia, and gout. Its gene product, GLUT9, was previously known as a type II glucose/fructose transporter but is now known to function as a high-capacity uric acid transporter that is expressed in kidney, liver, and several other tissues. Follow-up meta-analyses, including one with data from 28,141 individuals, implicated a total of nine additional loci influencing serum urate concentrations, including six other membrane transporters (SLC17A1, SLC17A3, SLC22A11, SLC22A12, SLC16A9, and ABCG2). Variants in these genes together account for about 5% of the variance in serum urate, two-thirds of which is due to SLC2A9. Using these variants in 'Mendelian randomization' analyses provides a powerful means of dissecting the role of urate in cardiovascular and metabolic diseases, where cause-and-effect influences are difficult to discern due to potential confounding. The results highlight the complex interplay of membrane transporters involved in urate metabolism. They also show how variants of weak effect identified by genome-wide association studies can still be important in identifying novel pathways, including a 'complexity' of new and potentially druggable targets for modifying urate transport.

The relation of coffee consumption to serum uric Acid in Japanese men and women aged 49-76 years

Objective. Few studies have suggested an inverse relation between coffee intake and serum concentrations of uric acid (UA), but none has addressed the relation in men and women separately. We examined the relation between coffee intake and serum UA levels in free-living middle-aged and elderly men and women in Fukuoka, Japan. Methods. Study subjects were derived from the baseline survey of a cohort study on lifestyle-related diseases, and included 11.662 men and women aged 49–76 years; excluded were those with medication for gout and hyperuricemia, use of diuretic drugs, and medical care for cancer or chronic kidney disease. Statistical adjustment was made for body mass index, alcohol use, hypertension, diabetes mellitus, and other factors. Results. There were inverse associations of coffee consumption with serum UA concentrations and hyperuricemia in men regardless of adjustment for covariates. Women showed a statistically significant, but weaker, inverse association between coffee and serum UA levels after allowance for the confounding factors. Conclusion. The findings add to evidence for a protective association between coffee intake and hyperuricemia.

Type 1 sodium-dependent phosphate transporter (SLC17A1 Protein) is a Cl(-)-dependent urate exporter

SLC17A1 protein (NPT1) is the first identified member of the SLC17 phosphate transporter family and mediates the transmembrane cotransport of Na(+)/P(i) in oocytes. Although this protein is believed to be a renal polyspecific anion exporter, its transport properties are not well characterized. Here, we show that proteoliposomes containing purified SLC17A1 transport various organic anions such as p-aminohippuric acid and acetylsalicylic acid (aspirin) in an inside positive membrane potential (Deltapsi)-dependent manner. We found that NPT1 also transported urate. The uptake characteristics were similar to that of SLC17 members in its Cl(-) dependence and inhibitor sensitivity. When arginine 138, an essential amino acid residue for members of the SLC17 family such as the vesicular glutamate transporter, was specifically mutated to alanine, the resulting mutant protein was inactive in Deltapsi-dependent anion transport. Heterologously expressed and purified human NPT1 carrying the single nucleotide polymorphism mutation that is associated with increased risk of gout in humans exhibited 32% lower urate transport activity compared with the wild type protein. These results strongly suggested that NPT1 is a Cl(-)-dependent polyspecific anion exporter involved in urate excretion under physiological conditions.

Relevance of uric Acid in progression of type 2 diabetes mellitus

Recent studies have introduced serum uric acid (UA) as a potential risk factor for developing diabetes, hypertension, stroke, and cardiovascular diseases. The value of elevated levels of UA in serum as a risk factor for diabetes development is still under scrutiny. Recent data suggest that clearance of UA is being reduced with increase in insulin resistance and UA as a marker of prediabetes period. However, conflicting data related to UA in serum of patients with Type 2 diabetes prompted us to study the urine/serum ratio of UA levels (USRUA) in these patients and healthy controls. All subjects included in the study were free of evidence of hepatitis B or C viral infection or active liver and kidney damage. Patients receiving drugs known to influence UA levels were also excluded from this study. Analysis of glucose and uric acid were performed on Dade Behring analyzer using standard IFCC protocols. Interestingly, our data demonstrated about 2.5 fold higher USRUA values in diabetic patients as compared to control subjects. Furthermore, there was a trend of correlation of USRUA value with the blood glucose levels in diabetic patients, which was more prominent in diabetic men than in women. With aging, levels of uric acid increased in serum of diabetic patients, and this effect was also more profound in male than in female diabetics. In conclusion, this study showed significantly elevated USRUA levels in patients with Type 2 diabetes, a negative USRUA correlation with the blood glucose levels in diabetic patients, and an effect of sex and age on the uric acid levels. Since literature data suggest a strong genetic effect on UA levels, it would be pertinent to perform further, possibly genetic studies, in order to clarify gender and ethnic differences in UA concentrations.

Hyperuricemia and coronary heart disease: a systematic review and meta-analysis

OBJECTIVE

The role of serum uric acid as an independent risk factor for cardiovascular disease remains unclear, although hyperuricemia is associated with cardiovascular disease such as coronary heart disease (CHD), stroke, and hypertension.

METHODS

A systematic review and meta-analysis using a random-effects model was conducted to determine the risk of CHD associated with hyperuricemia in adults. Studies of hyperuricemia and CHD were identified by searching major electronic databases using the medical subject headings and keywords without language restriction (through February 2009). Only prospective cohort studies were included if they had data on CHD incidences or mortalities related to serum uric acid levels in adults.

RESULTS

Twenty-six eligible studies of 402,997 adults were identified. Hyperuricemia was associated with an increased risk of CHD incidence (unadjusted risk ratio [RR] 1.34, 95% confidence interval [95% CI] 1.19-1.49) and mortality (unadjusted RR 1.46, 95% CI 1.20-1.73). When adjusted for potential confounding, the pooled RR was 1.09 (95% CI 1.03-1.16) for CHD incidence and 1.16 (95% CI 1.01-1.30) for CHD mortality. For each increase of 1 mg/dl in uric acid level, the pooled multivariate RR for CHD mortality was 1.12 (95% CI 1.05-1.19). Subgroup analyses showed no significant association between hyperuricemia and CHD incidence/mortality in men, but an increased risk for CHD mortality in women (RR 1.67, 95% CI 1.30-2.04).

CONCLUSION

Hyperuricemia may marginally increase the risk of CHD events, independently of traditional CHD risk factors. A more pronounced increased risk for CHD mortality in women should be investigated in future research.

The urate-lowering efficacy and safety of febuxostat in the treatment of the hyperuricemia of gout: the CONFIRMS trial

Introduction

The purpose of this study was to compare urate-lowering (UL) efficacy and safety of daily febuxostat and allopurinol in subjects with gout and serum urate (sUA) ≥ 8.0 mg/dL in a six-month trial.

Methods

Subjects (n = 2,269) were randomized to febuxostat 40 mg or 80 mg, or allopurinol 300 mg (200 mg in moderate renal impairment). Endpoints included the proportion of all subjects with sUA <6.0 mg/dL and the proportion of subjects with mild/moderate renal impairment and sUA <6.0 mg/dL. Safety assessments included blinded adjudication of each cardiovascular (CV) adverse event (AE) and death.

Results

Comorbidities included: renal impairment (65%); obesity (64%); hyperlipidemia (42%); and hypertension (53%). In febuxostat 40 mg, febuxostat 80 mg, and allopurinol groups, primary endpoint was achieved in 45%, 67%, and 42%, respectively. Febuxostat 40 mg UL was statistically non-inferior to allopurinol, but febuxostat 80 mg was superior to both (P < 0.001). Achievement of target sUA in subjects with renal impairment was also superior with febuxostat 80 mg (72%; P < 0.001) compared with febuxostat 40 mg (50%) or allopurinol (42%), but febuxostat 40 mg showed greater efficacy than allopurinol (P = 0.021). Rates of AEs did not differ across treatment groups. Adjudicated (APTC) CV event rates were 0.0% for febuxostat 40 mg and 0.4% for both febuxostat 80 mg and allopurinol. One death occurred in each febuxostat group and three in the allopurinol group.

Conclusions

Urate-lowering efficacy of febuxostat 80 mg exceeded that of febuxostat 40 mg and allopurinol (300/200 mg), which were comparable. In subjects with mild/moderate renal impairment, both febuxostat doses were more efficacious than allopurinol and equally safe. At the doses tested, safety of febuxostat and allopurinol was comparable.

Clinical Trial Registration

NCT00430248

Hyperuricemia and coronary heart disease: a systematic review and meta-analysis

OBJECTIVE

The role of serum uric acid as an independent risk factor for cardiovascular disease remains unclear, although hyperuricemia is associated with cardiovascular disease such as coronary heart disease (CHD), stroke, and hypertension.

METHODS

A systematic review and meta-analysis using a random-effects model was conducted to determine the risk of CHD associated with hyperuricemia in adults. Studies of hyperuricemia and CHD were identified by searching major electronic databases using the medical subject headings and keywords without language restriction (through February 2009). Only prospective cohort studies were included if they had data on CHD incidences or mortalities related to serum uric acid levels in adults.

RESULTS

Twenty-six eligible studies of 402,997 adults were identified. Hyperuricemia was associated with an increased risk of CHD incidence (unadjusted risk ratio [RR] 1.34, 95% confidence interval [95% CI] 1.19-1.49) and mortality (unadjusted RR 1.46, 95% CI 1.20-1.73). When adjusted for potential confounding, the pooled RR was 1.09 (95% CI 1.03-1.16) for CHD incidence and 1.16 (95% CI 1.01-1.30) for CHD mortality. For each increase of 1 mg/dl in uric acid level, the pooled multivariate RR for CHD mortality was 1.12 (95% CI 1.05-1.19). Subgroup analyses showed no significant association between hyperuricemia and CHD incidence/mortality in men, but an increased risk for CHD mortality in women (RR 1.67, 95% CI 1.30-2.04).

CONCLUSION

Hyperuricemia may marginally increase the risk of CHD events, independently of traditional CHD risk factors. A more pronounced increased risk for CHD mortality in women should be investigated in future research.

Sugar-sweetened soda consumption, hyperuricemia, and kidney disease

The metabolism of high-fructose corn syrup used to sweeten soda drinks may lead to elevations in uric acid levels. Here we determined whether soda drinking is associated with hyperuricemia and, as a potential consequence, reduced kidney function. At baseline, 15,745 patients in the Atherosclerosis Risk in Communities Study completed a dietary questionnaire and had measurements of their serum creatinine and uric acid. After 3 and 9 years of follow-up, multivariate odds ratios from logistic regressions for binary outcome of hyperuricemia and chronic kidney disease (eGFR less than 60 ml/min per 1.73 m(2)) were evaluated. Compared to participants who drank less, consumption of over one soda per day was associated with increased odds of prevalent hyperuricemia and chronic kidney disease. The odds ratio for chronic kidney disease significantly increased to 2.59 among participants who drank more than one soda per day and had a serum uric acid level over 9.0 mg/dl. In longitudinal analyses, however, drinking more than one soda per day was not associated with hyperuricemia or chronic kidney disease. Neither preexistent hyperuricemia nor development of hyperuricemia modified the lack of association between soda drinking and incident chronic kidney disease. Thus our study shows that high consumption of sugar-sweetened soda was associated with prevalent but not incident hyperuricemia and chronic kidney disease.

Hyperuricemia and risk of stroke: a systematic review and meta-analysis

OBJECTIVE

To assess the association between hyperuricemia and risk of stroke incidence and mortality because hyperuricemia is hypothesized to be a risk factor for stroke and other cardiovascular disease, but, to date, results from observational studies are conflicting.

METHODS

A systematic review and meta-analysis were conducted. Studies were identified by searching major electronic databases using the Medical Subject Headings and keywords without restriction in languages. Prospective cohort studies were included only if they contained data on stroke incidences or mortalities related to serum uric acid levels in adults. Pooled risk ratios (RRs) for the association of stroke incidence and mortality with serum uric acid levels were calculated.

RESULTS

A total of 16 studies including 238,449 adults were eligible and abstracted. Hyperuricemia was associated with a significantly higher risk of both stroke incidence (6 studies; RR 1.41, 95% confidence interval [95% CI] 1.05, 1.76) and mortality (6 studies; RR 1.36, 95% CI 1.03, 1.69) in our meta-analyses of unadjusted study estimates. Subgroup analyses of studies adjusting for known risk factors such as age, hypertension, diabetes mellitus, and cholesterol still showed that hyperuricemia was significantly associated with both stroke incidence (4 studies; RR 1.47, 95% CI 1.19, 1.76) and mortality (6 studies; RR 1.26, 95% CI 1.12, 1.39). The pooled estimate of multivariate RRs did not differ significantly by sex.

CONCLUSION

Hyperuricemia may modestly increase the risks of both stroke incidence and mortality. Future research is needed to determine whether lowering uric acid level has any beneficial effects on stroke.

Metabolic profiling of the response to an oral glucose tolerance test detects subtle metabolic changes

Background

The prevalence of overweight is increasing globally and has become a serious health problem. Low-grade chronic inflammation in overweight subjects is thought to play an important role in disease development. Novel tools to understand these processes are needed. Metabolic profiling is one such tool that can provide novel insights into the impact of treatments on metabolism.

Methodology

To study the metabolic changes induced by a mild anti-inflammatory drug intervention, plasma metabolic profiling was applied in overweight human volunteers with elevated levels of the inflammatory plasma marker C-reactive protein. Liquid and gas chromatography mass spectrometric methods were used to detect high and low abundant plasma metabolites both in fasted conditions and during an oral glucose tolerance test. This is based on the concept that the resilience of the system can be assessed after perturbing a homeostatic situation.

Conclusions

Metabolic changes were subtle and were only detected using metabolic profiling in combination with an oral glucose tolerance test. The repeated measurements during the oral glucose tolerance test increased statistical power, but the metabolic perturbation also revealed metabolites that respond differentially to the oral glucose tolerance test. Specifically, multiple metabolic intermediates of the glutathione synthesis pathway showed time-dependent suppression in response to the glucose challenge test. The fact that this is an insulin sensitive pathway suggests that inflammatory modulation may alter insulin signaling in overweight men.

Serum uric acid levels and risk of metabolic syndrome in healthy adults

OBJECTIVE

To investigate the relationship between hyperuricemia and metabolic syndrome in a population of healthy subjects.

METHODS

We studied 1,573 healthy adults (25 to 64 years old) in the population laboratory of the Tehran University of Medical Sciences. The study was designed according to the World Health Organization MONICA (Multinational Monitoring of Trends and Determinants in Cardiovascular Disease) project with use of the National Cholesterol Education Program Adult Treatment Panel III criteria for metabolic syndrome.

RESULTS

The crude prevalence of the metabolic syndrome was 29.9% (age-adjusted, 27.5%). The rate of metabolic syndrome significantly increased in higher quartiles of serum uric acid in both sexes but especially in women (P<.0001 versus P = .026). The bivariate correlation was significant between uric acid levels and age, total serum cholesterol, high-density lipoprotein cholesterol, triglycerides, body mass index, waist and hip circumferences, waist-to-hip ratio, and systolic and diastolic blood pressures; however, there was not a significant correlation between serum uric acid concentrations and fasting plasma glucose.

CONCLUSION

These data indicate that an independent relationship exists between hyperuricemia and the metabolic syndrome. Moreover, hyperuricemia is significantly correlated with hypertriglyceridemia, hypertension, and visceral obesity. Early detection of hyperuricemia seems to be essential for prevention of the metabolic syndrome.

We can make gout management more successful now

PURPOSE OF REVIEW

The purpose of this editorial review is to identify and comment on factors contributing to the current less-than-optimal state of gout management and to emphasize immediate opportunities to improve management practices affecting many patients with gout.

RECENT FINDINGS

Numerous publications document deficits in the current management and clinical outcomes of gout despite detailed understanding of the pathogenesis and pathophysiology of the disorder, the ability to establish the diagnosis with certainty, and the likely effectiveness, for most patients, of available lifestyle and pharmacological interventions. Among impediments to successful gout management are diagnostic inaccuracy; a paucity of validated management recommendations to guide care providers; incomplete patient education about gout and the aims and modalities of management; suboptimal patient adherence, even to demonstrably effective therapeutic recommendations; comorbidities and drug interferences that complicate treatment of gout; patient groups at special risk for progression to chronic tophaceous gout; and limited urate-lowering alternatives.

SUMMARY

Recent publication of evidence-based recommendations for the diagnosis and management of gout and the impending availability of new urate-lowering agents suggest that this is an opportune time to initiate professional and patient education efforts toward improved management of this increasingly common disorder.

SLC2A9 is a newly identified urate transporter influencing serum urate concentration, urate excretion and gout

Uric acid is the end product of purine metabolism in humans and great apes, which have lost hepatic uricase activity, leading to uniquely high serum uric acid concentrations (200-500 microM) compared with other mammals (3-120 microM). About 70% of daily urate disposal occurs via the kidneys, and in 5-25% of the human population, impaired renal excretion leads to hyperuricemia. About 10% of people with hyperuricemia develop gout, an inflammatory arthritis that results from deposition of monosodium urate crystals in the joint. We have identified genetic variants within a transporter gene, SLC2A9, that explain 1.7-5.3% of the variance in serum uric acid concentrations, following a genome-wide association scan in a Croatian population sample. SLC2A9 variants were also associated with low fractional excretion of uric acid and/or gout in UK, Croatian and German population samples. SLC2A9 is a known fructose transporter, and we now show that it has strong uric acid transport activity in Xenopus laevis oocytes.

Gouty attacks occur frequently in postoperative gastric bypass patients

BACKGROUND

Both obesity and surgery are known risk factors for instigating gouty attacks. We describe the incidence and management of postoperative gouty attacks after bariatric surgery.

METHODS

We performed a retrospective, multi-institutional review of 411 consecutive laparoscopic gastric bypass patients and identified all patients with postoperative gouty attacks.

RESULTS

Of the 411 patients reviewed, 21 (5.1%) had had a previous diagnosis of gout. Of these 21 patients, 7 (33.3%) had had an acute attack postoperatively. No patient who had never had a preoperative episode developed gout. In 4 of the 7 (57.1%) patients, the attack was severe enough to require treatment with corticosteroids. Monoarticular attacks occurred in 5 (71.4%) of the 7 patients, and polyarticular attacks occurred in 2 (28.6%). The joints involved included the toes, ankles, and wrists. One patient presented with cervical gout and developed polyarticular gout that required a significant rehabilitation stay.

CONCLUSION

The morbidity of postoperative gouty attacks in bariatric surgery patients is significant. Patients with a history of gout should given prophylactic treatment and closely monitored.

Relationship between hyperuricemia and metabolic syndrome

OBJECTIVE

To investigate the relationship between metabolic syndrome and hyperuricemia.

METHODS

A total of 2 374 subjects who received health examination in our hospital from Jan. 2004 to Dec. 2006 were enrolled in our study. Hyperuricemia is defined as >or=7 mg/dl (in men) or >or=6.0 mg/dl (in women). Metabolic syndrome was defined using AHA/NHLBI (American Heart Association/National Heart, Lung, and Blood Institute) criteria.

RESULTS

(1) The overall prevalence of hyperuricemia was 13.10%. The condition was more common in men than in women (19.07% vs 3.42%). (2) Among men, uric acid concentration is statistically significantly positively correlated with waist circumference, blood pressure, and triglyceride. Uric acid is negatively correlated with serum high-density lipoprotein-cholesterol (HDL-C). Uric acid concentration is most strongly correlated with serum triglyceride (r=0.379) and waist circumference (r=0.297). Among women, statistically significant positive correlations were noted for the serum uric acid concentrations with waist circumference, triglyceride and fasting plasma glucose. Serum triglyceride (r=0.329) and waist circumference (r=0.234) are most strongly correlated with uric acid concentrations. (3) Men with hyperuricemia had a 1.634-fold increased risk of metabolic syndrome as compared with those without hyperuricemia [odds ratio (OR)=1.634, P=0.000]. Women with hyperuricemia had a 1.626-fold increased risk of metabolic syndrome (OR=1.626, P=0.000) as compared with those without hyperuricemia.

CONCLUSION

Hyperuricemia is prevalent among Chinese population. Additionally, serum uric acid is positively associated with metabolic syndrome.

Metabolic syndrome-related conditions among people with and without gout: prevalence and resource use

OBJECTIVE

A cohort of employees with gout were compared to those without to evaluate the differences in prevalence of disorders associated with metabolic syndrome (both those considered underlying and those associated with end-stage morbidity and mortality) as well as the cost of annual medical services (AMS) required for treatment of these conditions.

METHODS

Employees with gout were identified by International Classification of Diseases-9 (ICD-9) code during the calendar years of 2001-2004 and compared to propensity-score matched employees without gout using the Human Capital Management Services Research Reference Database. T-tests were then used to compare prevalence and average AMS of comorbid disorders defined from Agency for Healthcare and Research Quality (AHRQ) diagnostic categories.

RESULTS

'Hyperlipidemia', 'essential hypertension', and 'diabetes mellitus without complications' ranked in the top 10 categories of mean number of AMS for employees with gout using AHRQ specific categories; the values were higher than found for those without gout (all p < 0.0001). 'Essential hypertension', 'hyperlipidemia', 'diabetes mellitus without complications', and 'coronary atherosclerosis' showed an approximate 2:1 prevalence ratio for employees with gout over those without (p < or = 0.05). Main study limitations include the small number of subjects with gout, retrospective study design, and possible miscoding and/or non-coding of individuals with the studied disorders.

CONCLUSION

These results support the continued need for patients with gout and their clinicians to be aware of the possibility of the increased risk of associated metabolic syndrome and related comorbidities in these individuals, emphasizing the need for prevention when possible and treatment when necessary.