Gout and hyperuricemia

HLA-B*58:01 allele is associated with augmented risk for both mild and severe cutaneous adverse reactions induced by allopurinol in Han Chinese

Aim: Allopurinol is widely used as an effective urate-lowering drug and is one of the most frequent causes of cutaneous adverse drug reactions (cADRs). Recently, a strong association of HLA-B*58:01 with allopurinol-induced severe cADRs was identified. This study investigated the predisposition to different types of allopurinol-cADRs conferred by HLA-B*5801 in a Han population from mainland China. Patients & methods:HLA-B genotyping was performed on 38 Chinese patients with different types of allopurinol-cADRs from 2008 to 2011. Results: All the allopurinol-cADR patients carried HLA-B*58:01, in contrast with only 11.11% (7/63) in the allopurinol-tolerant patients (odds ratio [OR] = 580.07; p < 0.0001) and 13.99% (80/572) in a Han Chinese population from the human MHC database (dbMHC; OR: 471.09; p < 0.0001) carried the genotype. Each type of allopurinol cADRs revealed a statistically significant association with HLA-B*58:01. In particular, the risk of allopurinol-induced maculopapular eruption was significantly higher in patients with HLA-B*58:01 (OR: 339.00; p < 0.0001). Conclusion: The strong association of both the mild and severe types of allopurinol cADRs with the HLA-B*58:01 allele were observed. The results indicated that the prospective use of a genetic test of HLA-B*58:01 might reduce the prevalence of allopurinol-induced cADRs.

Original submitted 7 March 2012; Revision submitted 21 May 2012

Association between HLA-B*58:01 allele and severe cutaneous adverse reactions with allopurinol in Han Chinese in Hong Kong

BACKGROUND

Allopurinol has been reported as a common cause of severe cutaneous adverse reactions (SCARs). Recent studies in various populations suggest that HLA-B*58:01 is a strong genetic marker for allopurinol-induced SCAR, especially in populations with a high frequency of HLA-B*58:01.

OBJECTIVES

To confirm the association link between HLA-B*58:01 and hypersensitivity reactions attributed to allopurinol use in Han Chinese patients in Hong Kong.

METHODS

We performed a case-control study to investigate whether the HLA-B*58:01 allele predisposes to allopurinol-induced SCAR in Han Chinese patients in Hong Kong. The HLA-B*58:01 genotyping was performed in 20 patients with allopurinol-induced SCAR or erythema multiforme major (EMM; n = 1) and in 30 patients tolerant to allopurinol.

RESULTS

All of the 19 patients with allopurinol-induced SCAR examined but not the patient with EMM carried HLA-B*58:01 whereas only four (13%) of the control patients had this allele. The positive rate of the HLA-B*58:01 was significantly higher in the cases than in the allopurinol-tolerant control group [odds ratio (OR) 123·5, 95% confidence interval (CI) 12·8-1195·1; P < 1 × 10(-4) ] and was even higher after removal of the patient with EMM (OR 229·7, 95% CI 11·7-4520·4). The sensitivity and specificity of the HLA-B*58:01 allele for prediction of allopurinol-induced SCAR were 100% and 86·7%, respectively.

CONCLUSIONS

This study confirmed the strong association between the HLA-B*58:01 and allopurinol-induced SCAR in Hong Kong Han Chinese patients. A screening test for the HLA-B*58:01 allele should effectively reduce the risk for allopurinol-induced SCAR in Chinese populations.

Decreased extra-renal urate excretion is a common cause of hyperuricemia

ABCG2, also known as BCRP, is a high-capacity urate exporter, the dysfunction of which raises gout/hyperuricemia risk. Generally, hyperuricemia has been classified into urate 'overproduction type' and/or 'underexcretion type' based solely on renal urate excretion, without considering an extra-renal pathway. Here we show that decreased extra-renal urate excretion caused by ABCG2 dysfunction is a common mechanism of hyperuricemia. Clinical parameters, including urinary urate excretion, are examined in 644 male outpatients with hyperuricemia. Paradoxically, ABCG2 export dysfunction significantly increases urinary urate excretion and risk ratio of urate overproduction. Abcg2-knockout mice show increased serum uric acid levels and renal urate excretion, and decreased intestinal urate excretion. Together with high ABCG2 expression in extra-renal tissues, our data suggest that the 'overproduction type' in the current concept of hyperuricemia be renamed 'renal overload type', which consists of two subtypes-'extra-renal urate underexcretion' and genuine 'urate overproduction'-providing a new concept valuable for the treatment of hyperuricemia and gout.

Living with gout in New Zealand: an exploratory study into people's knowledge about the disease and its treatment

BACKGROUND

In New Zealand, gout disproportionately affects Māori and Pacific people who also experience symptoms at an earlier age. Gout occurs predominantly in men and is associated with cardiovascular disease, diabetes, and renal disease. The impact on daily social activities, family, and work is enormous, and many people remain inadequately treated.

OBJECTIVES

The objectives of this study were to explore the knowledge and perceptions of people with gout toward the disease and to determine the impact gout has on lifestyle including possible barriers to treatment.

METHODS

Sixty people with gout from the Auckland and Waikato regions of New Zealand were invited to participate in 30-minute semistructured interviews. The data were analyzed using a general inductive thematic approach.

RESULTS

Although 85% of participants were aware of dietary triggers of gout, these were not always avoided. Less than 50% knew something about how their medicines worked, and only 33% knew which medicines to use both acutely and chronically. The negative impact of gout episodes was noted through the number participants unable to work or participate in family activities. Healthcare professionals were not always the main source of information, which is an area that could be developed to improve knowledge about gout.

CONCLUSIONS

There were substantial gaps in the knowledge about gout and its causes and management. All healthcare providers could help identify patients with suboptimal knowledge and improve the management of gout.

A whole-genome association study of major determinants for allopurinol-related Stevens-Johnson syndrome and toxic epidermal necrolysis in Japanese patients

Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS/TEN) are severe, cutaneous adverse drug reactions that are rare but life threatening. Genetic biomarkers for allopurinol-related SJS/TEN in Japanese were examined in a genome-wide association study in which Japanese patients (n=14) were compared with ethnically matched healthy controls (n=991). Associations between 890 321 single nucleotide polymorphisms and allopurinol-related SJS/TEN were analyzed by the Fisher's exact test (dominant genotype mode). A total of 21 polymorphisms on chromosome 6 were significantly associated with allopurinol-related SJS/TEN. The strongest association was found at rs2734583 in BAT1, rs3094011 in HCP5 and GA005234 in MICC (P=2.44 × 10(-8); odds ratio=66.8; 95% confidence interval, 19.8-225.0). rs9263726 in PSORS1C1, also significantly associated with allopurinol-related SJS/TEN, is in absolute linkage disequilibrium with human leukocyte antigen-B*5801, which is in strong association with allopurinol-induced SJS/TEN. The ease of typing rs9263726 makes it a useful biomarker for allopurinol-related SJS/TEN in Japanese.

Anti-hyperuricemic and nephroprotective effects of Smilax china L

ETHNOPHARMACOLOGICAL RELEVANCE

Smilax china L., popularly known as "Jin Gang Ten", has been widely used as a traditional herbal medicine for the treatment of gout, rheumatoid arthritis and other diseases for a long time in China.

AIM OF STUDY

The present study was carried out to investigate the effect of Smilax china L. on hyperuricemia and renal dysfunction in induced hyperuricemic animals.

MATERIALS AND METHODS

Five fractions (petroleum ether, chloroform, ethyl acetate, n-butanol and residual ethanol fraction) of Smilax china L. were orally administered to potassium oxonate-induced hyperuricemic mice for three days. The xanthine oxidase inhibitory activities and modes of action of nine compounds isolated from ethyl acetate fraction (EAF) were then examined in vitro. Finally, different dosages of EAF were administered to 10% fructose-induced hyperuricemic rats.

RESULTS

EAF (250 mg/kg) exhibited stronger anti-hyperuricemic activity in hyperuricemic mice compared with the other four fractions. Caffeic acid, resveratrol, rutin and oxyresveratrol isolated from EAF showed different inhibitory activities on xanthine oxidase in vitro, with the IC(50) values of 42.60, 37.53, 42.20 and 40.69 μM, respectively, and exhibited competitive or mixed inhibitory actions. Moreover, EAF (125, 250 and 500 mg/kg) markedly reversed the serum uric acid level (p<0.05, p<0.01 and p<0.001, respectively), fractional excretion of urate (p<0.05, p<0.01 and p<0.01, respectively) and blood urea nitrogen (p<0.05, p<0.01 and p<0.01, respectively) to their normal states, and prevented the renal damage against tubulointerstitial pathologies in hyperuricemic rats.

CONCLUSION

These findings show that Smilax china L. exhibits anti-hyperuricemic and nephroprotective activity in hyperuricemic animals.

HLA-B58 can help the clinical decision on starting allopurinol in patients with chronic renal insufficiency

BACKGROUND

Although allopurinol is a very effective urate-lowering drug for complicated hyperuricemia, in some patients, it can induce severe cutaneous adverse reactions (SCARs). Recent investigations suggest that HLA-B*5801 is a very strong marker for allopurinol-induced SCARs, especially in the population with a high frequency of HLA-B*5801. Korea is one of the countries with a high frequency of HLA-B*5801 which is the only subtype of HLA-B58 in the Korean population. Objective. This study was conducted to find out the incidence of allopurinol-induced hypersensitivity on patients with chronic renal insufficiency (CRI) according to HLA-B58 and the clinical implications of HLA-B58 as a risk marker for the development of allopurinol-induced hypersensitivity.

METHODS

We retrospectively reviewed the medical records of patients with CRI who took allopurinol and carried out serologic human leukocyte antigen (HLA) typing for kidney transplantation between January 2003 and May 2010.

RESULTS

Among a total of 448 patients with CRI, 16 (3.6%) patients experienced allopurinol hypersensitivity. Nine of these patients (2.0%) were diagnosed with SCARs (two Stevens-Johnson syndrome and seven allopurinol hypersensitivity syndrome) and seven patients (1.6%) had simple maculopapular rashes. The HLA-B58 allele was present in all patients with allopurinol-induced SCARs, while the frequency of HLA-B58 was only 9.5% in allopurinol-tolerant patients (P < 0.05). The incidence of allopurinol-induced SCARs in CRI shows a wide disparity according to HLA-B58 [18% in HLA-B58 (+) versus 0% in HLA-B58 (-)]. Among patients without HLA-B58, most (98.2%) of the CRI patients were tolerant to allopurinol and only 1.8% experienced simple rashes after taking allopurinol.

CONCLUSIONS

In this study, the incidence of allopurinol-induced SCARs was considerably high in CRI patients with HLA-B58. This finding indicates that the presence of HLA-B58 may increase the risk of allopurinol-induced SCARs. Screening tests for HLA-B58 in CRI patients will be clinically helpful in preventing severe allopurinol hypersensitivity reactions.

Synthesis and biological activity of pyrazolo[3,4-d]thiazolo[3,2-a]pyrimidin-4-one derivatives: in silico approach

Xanthine oxidase (XO) is responsible for the pathological condition called gout. Inhibition of XO activity by various pyrazolo[3,4-d]thiazolo[3,2-a]pyrimidine-4-one derivatives was assessed and compared with the standard inhibitor allopurinol. Out of 10 synthesized compounds, two compounds, viz. 3-amino-6-(2-hydroxyphenyl)-1H-pyrazolo[3,4-d]thiazolo[3,2-a]pyrimidin-4-one (3b) and 3-amino-6-(4-chloro-2-hydroxy-5-methylphenyl)-1H-pyrazolo[3,4-d]thiazolo[3,2-a]pyrimidin-4-one (3g) were found to have promising XO inhibitory activity of the same order as allopurinol. Both compounds and allopurinol inhibited competitively with comparable Ki (3b: 3.56 microg, 3g: 2.337 microg, allopurinol: 1.816 microg) and IC(50) (3b: 4.228 microg, 3g: 3.1 microg, allopurinol: 2.9 microg) values. The enzyme-ligand interaction was studied by molecular docking using Autodock in BioMed Cache V. 6.1 software. The results revealed a significant dock score for 3b (-84.976 kcal/mol) and 3g (-90.921 kcal/mol) compared with allopurinol (-55.01 kcal/mol). The physiochemical properties and toxicity of the compounds were determined in silico using online computational tools. Overall, in vitro and in silico study revealed 3-amino-6-(4-chloro-2-hydroxy-5-methylphenyl)-1H-pyrazolo[3,4-d]thiazolo[3,2-a]pyrimidin-4-one (3g) as a potential lead compound for the design and development of XO inhibitors.

Allopurinol to Febuxostat: How far have we come?

For decades allopurinol has been used as a xanthine oxidase inhibitor for treatment of hyperuricemia and gout. Although effective in many patients, some experience sensitivity to the drug. In some cases, this sensitivity may lead to allopurinol hypersensitivity disorder, which if untreated can be fatal. Recently the Food and Drug Administration has approved the use of febuxostat as an alternative therapy for hyperuricemia and gout. Febuxostat is a new xanthine oxidase inhibitor, but is not purine based and therefore decreases adverse reactions due to patient sensitivity. This review is a comprehensive look at the background of hyperuricemia and gout treatment with allopurinol compared to recent clinical studies with febuxostat. Each clinical study is evaluated and summarized, identifying the advances in treatment that have been made as well as the concerns that still exist with either treatment.

Dietary purines in vegetarian meat analogues

BACKGROUND

The meat alternatives market offers a wide range of products resembling meat in taste, flavour or texture but based on vegetable protein sources. These high protein-low purine foods may find application in a low purine or purine-free diet, which is sometimes suggested for subjects with increased serum urate levels, i.e. hyperuricaemia.

RESULTS

We determined purine content (uric acid, adenine, guanine, hypoxanthine, xanthine) in 39 commercially available meat substitutes and evaluated them in relation to their protein content. Some of the products contained a comparable sum of adenine and hypoxanthine per protein as meat. Analysis of variance showed an influence of protein source used. Mycoprotein-based products had significantly higher contents (2264 mg kg(-1)) of adenine and hypoxanthine per kg of 100% protein than soybean-based products (1648 mg kg(-1)) or mixtures consisting of soybean protein and wheat protein (1239 mg kg(-1)).

CONCLUSION

Protein-rich vegetable-based meat substitutes might be generally accepted as meat alternatives for individuals on special diets. The type of protein used to manufacture these products determines the total content of purines, which is relatively higher in the case of mycoprotein or soybean protein, while appearing lower in wheat protein and egg white-based products. These are therefore more suitable for dietary considerations in a low-purine diet for hyperuricaemic subjects.

Prediction of severe adverse drug reactions using pharmacogenetic biomarkers

Severe adverse drug reactions (ADRs) are a major issue for drug therapy because they can cause serious disorders and be life-threatening. Many severe ADRs appear to be idiosyncratic and unpredictable. Genetic factors may underlie susceptibility to severe ADRs, and identification of predisposing genotypes may improve drug therapy by facilitating prescreening of carriers for specific genetic biomarkers. In this review, we clarify the current status of ADRs in Japan from open ADR data sources. Then, we introduce recent progress in the field of pharmacogenetic biomarkers for severe cutaneous ADRs, liver injury, and statin-induced myopathy. Key challenges for discovery of predictable risk alleles for these severe ADRs are also discussed.

Cochlear dysfunction in hyperuricemia: otoacoustic emission analysis

PURPOSE

The objective of this study is to provide evidence that primary hyperuricemia is associated with cochlear dysfunction as other metabolic diseases that interfere with cell metabolism.

MATERIALS AND METHODS

Cochlear function was evaluated in 25 subjects with asymptomatic hyperuricemia using routine diagnostic audiometry along with transient evoked and distortion product otoacoustic emissions (TEOAE and DPOAE, respectively). To support the notion that vascular compromise was a significant underlying factor for such cochlear dysfunction, we assessed vascular anatomical and functional states through measuring the common carotid artery intima-media thickness and flow velocity of the basal intracranial vessels.

RESULTS

Compared with control subjects, reduced response levels of TEOAEs (P < .01) and amplitudes of DPOAEs (P < .001) were detected at higher frequencies. The reduced DPOAE levels at 5 kHz and TEOAEs at 4 kHz correlated significantly with uric acid (P < .05; P < .01), patients' age (P < .06; P < .05), duration since diagnosis of hyperuricemia (P < .05; P < .001), common carotid artery intima-media thickness (P < .05), mean flow velocities of middle cerebral arteries (P < .05), and vertebral arteries (P < .01). Multivariate analysis showed that the abnormalities at higher frequencies were significantly correlated with the duration and degree of hyperuricemia.

CONCLUSIONS

These data suggest that subclinical changes in cochlear function are associated with hyperuricemia. They support the usefulness of otoacoustic emissions in early detection of cochlear dysfunction. It is possible that hyperuricemia could be accompanied by increased stiffness and/or compromise of blood supply of the outer hair cells, which will impair their electromotile response.

Febuxostat: a selective xanthine-oxidase/xanthine-dehydrogenase inhibitor for the management of hyperuricemia in adults with gout

BACKGROUND

Febuxostat, a nonpurine selective inhibitor of both the oxidized and reduced forms of xanthine oxidase, was approved in February 2009 by the US Food and Drug Administration for the management of hyperuricemia in adults with gout.

OBJECTIVE

The purpose of this review was to summarize available information about the clinical use of febuxostat, including its chemistry, pharmacology, pharmacokinetics, pharmacodynamics, clinical efficacy, and safety profile.

METHODS

A search of the medical literature using PubMed (1949-August 2009) and the Iowa Drug Information Service (1966-August 2009) was performed to identify all published articles about febuxostat. Key search terms included febuxostat, hyperuricemia, gout, TMX-67, and TEI-6720. Articles were limited to those published in English. Reference lists of the primary set of articles identified were reviewed for pertinent articles and scientific meeting abstracts not identified in the original search.

RESULTS

A total of 88 published articles (including 14 human studies) were identified in the original search. Review of the references of these 88 articles yielded 7 additional trials published in abstract form. Clinical trial data from this review were obtained from these 21 studies. Dose-dependent reductions from baseline in serum urate occur with febuxostat. Clinical trials found that 40 mg/d of febuxostat was noninferior to conventionally dosed allopurinol (300 mg/d) in the percentage of subjects achieving the primary end point of serum urate <6.0 mg/dL (45% for febuxostat vs 42% for allopurinol), whereas 80 mg/d of febuxostat was reported to be superior (67% vs 42%; P < 0.001). Febuxostat 40 and 80 mg/d appeared to be well tolerated in the populations studied, with adverse events mostly limited to liver enzyme elevations (6.6% and 4.6%, respectively), nausea (1.1% and 1.3%), arthralgias (1.1% and 0.7%), and rash (0.5% and 1.6%). Febuxostat does not require dosage adjustment in patients with mild to moderate renal impairment (creatinine clearance, 30-89 mL/min). Because of the risk of acute gout flares occurring when febuxostat treatment is initiated, concomitant therapy with colchicine or an NSAID for >or=8 weeks is recommended.

CONCLUSIONS

Febuxostat is the first agent marketed in the United States to treat hyperuricemia of gout since allopurinol was approved in 1964. In English-language published clinical trials, it was found to be noninferior to allopurinol and generally well tolerated.

[Allopurinol-induced hypersensitivity syndrome resulting in death]

The present report describes the case of a 67-year-old patient who developed an allopurinol-induced hypersensitivity syndrome (AHS) with toxic epidermal necrolysis and subsequently died of septic multiorgan failure. Considering the increasing prescription rate of allopurinol, the present case report intends to demonstrate the underestimated threat of AHS.

Update on gout: new therapeutic strategies and options

Gout, a disease recognized since antiquity, has increased in prevalence in recent years and the clinical profile of this disease has become increasingly complex, owing to large numbers of cases with iatrogenic factors, multiple comorbidities, advanced age, and hyperuricemia and arthritis refractory to treatment. In this Review, key advances in gout research made during the past decade are summarized. Revised strategies for safe and effective employment of dietary measures and pharmacologic treatments for active gouty arthritis, prevention of gout flares and urate lowering are also reviewed, with an emphasis on dosing of colchicine and allopurinol, and the evidence-based approach to systemic glucocorticosteroid treatment of acute gout. Also discussed are new and emerging treatments for gout and hyperuricemia, and the potential influence of dual energy CT imaging on treatment. In this context, the therapeutic role of febuxostat, and clinical development of pegylated uricase urate-lowering therapy and interleukin 1 antagonism for gouty inflammation are reviewed. Collectively, novel approaches will hopefully lead to improved management of hyperuricemia and gout, and also to improvements in patient-centered outcomes, even for those who have previously failed to respond to treatment.

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.

Advances in the management of gout and hyperuricaemia

An acute attack of gouty arthritis is one of the most painful experiences reported throughout medical history. Therefore it is paramount to initiate appropriate therapy quickly in order to terminate the acute phase. This goal can be achieved with non-steroidal anti-inflammatory agents, colchicine, or corticosteroid-based therapies. Rarely, because of contraindications to these agents, only symptomatic treatment can be given until the attack subsides. The next step is to lower the serum urate level below the limit of solubility (i.e., below 40.8 mmol/L, or 6.8mg/dL) which reduces recurrences and begins to return the total body urate pool to normal. This equally important goal can be achieved by uricosuric agents or xanthine oxidase inhibitors, although the latter is generally favored. Allopurinol is the agent most commonly preferred because of its safety profile and ease of use, but there are known serious allergic reactions and untoward side effects that occasionally require discontinuation. Febuxostat, a xanthine oxidase inhibitor, and pegylated uricase are new agents under development and may be beneficial in these situations or when other comorbid conditions prevent the use of conventional treatments. Alcohol and dietary consumption are also related to hyperuricemia and acute gout. Recently beer, wine, and liquor were studied and the risk of gout varied according to the alcohol ingested. Furthermore, recent data sheds light on important dietary modifications that may help in the treatment of gout, and dispels certain beliefs about protein ingestion and the occurrence of acute gout. As we learn more about the associated conditions of hypertriglyceridemia, hypertension, and the metabolic syndrome, it may allow the tailoring of medical regimens that directly prevent or reduce recurrent attacks of gouty arthritis. There are specific approved treatments for these common comorbidities that have parallel effects of lowering serum urate levels. These recent findings may be especially important for treating refractory cases. While patient education remains a cornerstone to ensure compliance, other quality indicators for the management of this disease have been reported and should guide the clinician in the treatment of gout and result in improved care.

Frequency, risk, and cost of gout-related episodes among the elderly: does serum uric acid level matter?

OBJECTIVE

We examined the association between serum uric acid (SUA) level and the frequency, risk, and cost of gout flares among the elderly.

METHODS

Data were extracted from the Integrated Healthcare Information Services claims database (1999-2005). Patients were included if they had gout, were aged 65 years and older and had both medical and pharmacy benefits, and electronic laboratory data. Patients with gout and gouty episodes were identified using algorithms based on ICD-9-CM codes and medications. Logistic regression and negative binomial regressions were used to study the relationship between SUA concentration and the annual frequency and one-year risk of gout episodes. Generalized linear models were used to examine the direct healthcare costs associated with gout episodes in the 30 days following each episode.

RESULTS

Elderly patients with gout (n = 2237) with high (6-8.99 mg/dl) and very high (> 9 mg/dl) SUA concentrations were more likely to develop a flare within 12 months compared to patients with normal (< 6 mg/dl) SUA levels (OR 2.1, 95% CI 1.7-2.6; OR 3.4, 95% CI 2.6-4.4, respectively). In multivariate regressions, the average annual number of flares increased by 11.9% (p < 0.001) with each unit-increase in SUA level above 6 mg/dl (p < 0.001). Among patients with very high SUA levels, average adjusted total healthcare and gout-related costs per episode were $2,555 and $356 higher, respectively, than those of patients with normal SUA levels (both p < 0.001).

CONCLUSION

Higher SUA levels are associated with increased frequency and risk of gout episode, and with higher total and gout-related direct healthcare costs per episode.

Febuxostat in the management of hyperuricemia and chronic gout: a review

Febuxostat is a novel, potent, non-purine selective xanthine oxidase inhibitor, which in clinical trials demonstrated superior ability to lower and maintain serum urate levels below 6 mg/dL compared with conventionally used doses of allopurinol. Febuxostat was well tolerated in long term treatment in patients with hyperuricemia including those experiencing hypersensitity/intolerance to allopurinol. Dose adjustment appears unnecessary in patients with mild to moderate renal or liver insufficiency or advanced age. The most common adverse reactions reported were abnormal liver function tests, headache, and gastrointestinal symptoms, which were usually mild and transient. However, whether hepatotoxicity becomes a limitation in the use of febuxostat needs to be determined in further studies. An increased frequency of gout flares occurs for a prolonged period after treatment initiation, as with any aggressive lowering of serum urate, and prolonged prophylaxis with colchicine or NSAIDs is usually required. Febuxostat has been granted marketing authorization by the European Commission in early 2008 for the treatment of chronic hyperuricemia and gout. Febuxostat is the first major treatment alternative for gout in more than 40 years and is a promising alternative to allopurinol, although continued long-term surveillance on safety and efficacy is required.

Salvage of the first ray with concomitant septic and gouty arthritis by use of a bone block joint distraction arthrodesis and external fixation

Gouty arthropathy about the first metatarsal-phalangeal joint with a superimposed deep infection poses a great challenge to the foot and ankle surgeon. The inflammatory nature of gout compromises the soft-tissue envelope and vasculature to the area. Acute gouty arthropathy is usually a contraindication to surgical intervention secondary to wound-healing complications and possible vasospasm leading to tissue necrosis. However, if deep infection is present this must be managed with adequate surgical débridement followed by delayed soft-tissue and osseous reconstruction to prevent amputation. The authors present an exceptional clinical manifestation of gouty arthropathy of the first metatarsal-phalangeal joint concomitant with deep abscess and osteomyelitis and the surgical approach taken to afford functional limb salvage.

Pharmacogenetic information derived from analysis of HLA alleles

A large amount of pharmacogenetic information has, in particular, accumulated on the association between human leukocyte antigen (HLA) alleles and hypersensitivity to certain drugs. Prospective HLA typing has dramatically reduced the risk of abacavir hypersensitivity because of its strong association with HLA-B*5701. Significant predisposition to nevirapine hypersensitivity has been reported in Caucasian Australians harboring HLA-DRB1*0101 with high CD4+ T-cell counts, and Sardinians and Japanese harboring HLA-Cw8. A strong association between carbamazepine hypersensitivity and HLA-B*1502 has been reported in Han Chinese. Most Han Chinese individuals with allopurinol-induced severe cutaneous adverse reactions are positive for HLA-B*5801. HLA typing can stratify risk of hypersensitivity to certain drugs and allow personalized treatment, although the patients should be monitored closely even if they are negative for HLA alleles associated with hypersensitivity.

Association of baseline disease and patient characteristics with response to etoricoxib and indomethacin for acute gout

BACKGROUND AND OBJECTIVE

Disease history and clinical features can influence treatment response in patients with acute gout. The purpose of this pooled subgroup analysis was to assess the association of baseline disease and patient characteristics with response to treatment in acute gout using data from two identical studies.

METHODS

Patients > or = 18 years of age with onset of acute gout within 48 h associated with moderate, severe, or extreme pain involving less than four joints were eligible for inclusion in the primary studies, and were randomized to etoricoxib 120 mg once daily (N = 178) or indomethacin 50 mg three times daily (N = 161). The primary and secondary efficacy endpoints were analyzed using an analysis of covariance model to detect potential differential treatment responses across several subgroups: joint involvement (mono-articular vs. oligo-articular), baseline pain severity (moderate vs. severe), concomitant allopurinol and/or colchicine use (users vs. nonusers), age (< 45, 45-55, and > 55 years), gender, and race (white or other).

RESULTS

Overall, etoricoxib and indomethacin demonstrated comparable efficacy across all subgroups. Compared with patients with oligo-articular disease, those with mono-articular disease had significantly greater improvements in patient assessment of pain, patient global assessment of response to therapy (PGART), investigator global assessment of response to therapy (IGART), and study joint tenderness (p < 0.001 for all). Greater improvements were seen in patient assessment of pain (p < 0.001) and study joint tenderness (p < 0.05) for severe/extreme baseline pain compared with moderate baseline pain. Concomitant use of colchicine and/or allopurinol was associated with significantly worse IGART (p < 0.05).

CONCLUSIONS

This pooled subgroup analysis demonstrated significantly greater response of acute gout to either etoricoxib or indomethacin among those with monoarticular disease, severe/extreme baseline pain, and non-use of colchicine and/or allopurinol. These results should be interpreted in the context of a pooled subgroup analysis with a limited sample size, and with the understanding that associations identified in such analyses do not define causation. Despite limitations, the results provide insights into the types of patients more likely to respond better to anti-inflammatory medication, and reiterate the importance of earlier effective control of the disease.

Hypouricemic effect and regulatory effects on autonomic function of Shao-Yao Gan-Cao Tang, a Chinese herbal prescription, in asymptomatic hyperuricemic vegetarians

Shao-yao Gan-Cao Tang (SYGCT) is a popular Chinese herbal prescription which is composed of Paeoniae Radix and Glycyrrhizae Radix. The uric acid-lowering effects and regulatory effects on autonomic functions of SYGCT in vegetarians with asymptomatic hyperuricemia were evaluated in the present study. All the hyperuricemic vegetarians in experimental group and the normal healthy subjects in control group were administered SYGCT three times daily for 4 weeks. The blood levels of uric acid and general autonomic system function examinations were performed at baseline and after 4-week treatment. The activities of autonomic function were evaluated by a modified method from Wenger's analyses of autonomic variables. After 4-week treatment of SYGCT, a significant reduction of serum uric acid levels was found in the hyperuricemic vegetarians. SYGCT could increase the sympathetic activities of the hyperuricemic vegetarians with deficient-syndrome, but had no significant effects in the excess-syndrome subjects.

Management of gout in older adults: barriers to optimal control

Gout, a common inflammatory arthritis, can be diagnosed with absolute certainty. Gout results from the body's reaction to urate crystals deposited in tissues, and this pathophysiology is well understood. If used appropriately, available therapies can be entirely effective in not only treating the symptoms of gout, but also in eliminating the excess urate from the body, thereby eradicating the disease. Because of these facts, management of patients with gout should be successful. However, management of gout is particularly challenging in the elderly, even though the principles of management are the same for all age groups. The purpose of this article is to review these principles and discuss them as they pertain to the elderly. The classic gout attack is acute in onset, extremely painful and associated with marked swelling, warmth, erythema and tenderness of a single joint. However, the diagnosis of gout may be challenging in the elderly because atypical presentations are more common in this group. Treatment of acute gout involves the use of NSAIDs, colchicine, corticosteroids or corticotropin (adrenocorticotropic hormone). Unfortunately, co-morbid conditions such as chronic kidney disease, peptic ulcer disease and congestive heart failure may make the use of these agents dangerous or contraindicated. Thus, it is important to try to treat an acute flare of gout at the earliest sign, because the sooner treatment is initiated, the faster the inflammation will resolve. Urate-lowering agents include allopurinol and uricosuric agents. These also must be used judiciously in the elderly. However, if used at the lowest dose that maintains the serum urate level below 5.0-6.0 mg/dL, the excess urate in the body will be eliminated, acute flares will no longer occur and tophi will resolve. Gout is often seen in association with hypertension, excessive alcohol consumption, obesity and hypertriglyceridaemia. These conditions and the medications used to treat them may contribute to the hyperuricaemia. Treating these conditions and using medications that do not promote hyperuricaemia will aid in the management of gout. Despite the challenges that often complicate the management of gout in the elderly, an understanding of the pathophysiology of the disease and both the indications and limitations of the medications used should allow successful treatment.

Prevalence of hyperuricemia and its relationship with metabolic syndrome in Thai adults receiving annual health exams

BACKGROUND

Associations between hyperuricemia, metabolic syndrome, cardiovascular disease and diabetes have been reported. Limited information, however, is available concerning the prevalence and correlates of hyperuricemia among Thai men and women. We sought to estimate the prevalence of hyperuricemia among a population of patients receiving annual health exams and to evaluate its relationship with metabolic syndrome (MetS).

METHODS

We conducted a cross-sectional study of 1,381 patients (376 men and 1,005 women) who first participated in annual health examinations at the Preventive Medicine Clinic of the King Chulalongkorn Memorial Hospital in Bangkok, Thailand during the period July 1999 through February 2000. Hyperuricemia was defined as >7.0 mg/dL in men and >6.0 mg/dL in women. MetS was defined using the modified ATP III criteria.

RESULTS

The overall prevalence of the hyperuricemia was 10.6%. The condition was more common in men than in women (18.4 vs. 7.8%). Among women, serum uric acid was statistically significantly correlated with body mass index (BMI), systolic and diastolic blood pressure, high-density lipoprotein-cholesterol, triglyceride and fasting plasma glucose (all p <0.05). Men with serum uric acid concentrations >6.7 mg/dL (upper quartile) had a 3.91-fold increased in risk of MetS (95% CI:1.36-11.23), as compared with those who had concentrations <5.1 mg/dL (lowest quartile). Among women, the risk of MetS increased at least 2-fold for concentration of serum uric acid concentrations >4.0 mg/dL (p for trend <0.001).

CONCLUSIONS

Hyperuricemia is prevalent among Thai men and women receiving routine health exams. Additionally, serum uric acid is positively associated with MetS.

Colchicine for acute gout

BACKGROUND

Gout is one of the most common rheumatic diseases worldwide. Colchicine is regarded as beneficial in the treatment of acute gout, but has a high frequency of gastrointestinal adverse events.

OBJECTIVES

To evaluate the efficacy and safety of colchicine for relief of the signs and symptoms of acute gouty arthritis, compared to placebo and other treatment interventions.

SEARCH STRATEGY

We searched the following electronic databases to March 2006: Cochrane Central Register of Controlled Trials (CENTRAL, Issue 1, 2006), MEDLINE (from 1966), EMBASE (from 1980), CINAHL (from 1982), AMED (from 1985), Web of Science (from 1945) and Current Controlled Trials.

SELECTION CRITERIA

Published randomised controlled trials (RCTs) and controlled clinical trials evaluating symptom relief and adverse outcomes of colchicine therapy in acute gout were considered for this review.

DATA COLLECTION AND ANALYSIS

Two reviewers independently screened search results for inclusion, collected the data in a standardized form and assessed the methodological quality of the trial using validated criteria. Results for continuous outcome measures were expressed as weighted mean differences. Dichotomous outcome measures were pooled using relative risk. The number needed to treat was calculated for significant outcomes.

MAIN RESULTS

One RCT (N=43) comparing colchicine to placebo for the treatment of acute gout was included in this review. The results favour the use of colchicine over placebo with an absolute reduction of 34% for pain and a 30% reduction in clinical symptoms such as tenderness on palpation, swelling, redness, and pain. The number needed to treat (NNT) with colchicine versus placebo to reduce pain was 3 and the NNT to reduce clinical symptoms was 2. All participants treated with colchicine experienced gastrointestinal side effects (diarrhea and/or vomiting) and the number needed to harm (NNH) with colchicine versus placebo was 1. No studies comparing colchicine to NSAIDs or other treatments such as corticosteroids or ACTH were identified.

AUTHORS' CONCLUSIONS

Colchicine is an effective treatment for the reduction of pain and clinical symptoms in patients experiencing acute attacks of gout, although in the regimen studied its low benefit to toxicity ratio limits its usefulness. It should be used as a second line therapy when NSAIDs or corticosteroids are contraindicated or ineffective. More evidence is needed to compare the efficacy of colchicine to that of NSAIDs or corticosteroids, the current first line therapy for acute gout.

Longevity-associated NADH dehydrogenase subunit-2 237 Leu/Met polymorphism influences the effects of alcohol consumption on serum uric acid levels in nonobese Japanese men

NADH dehydrogenase subunit-2 237 leucine/methionine (ND2-237 Leu/Met) polymorphism is reportedly associated with longevity in the Japanese population. The ND2-237Met genotype may confer resistance to cardiovascular and cerebrovascular atherogenic diseases. Hyperuricemia is one of the risk factors for cardiovascular disease. To investigate whether ND2-237 Leu/Met polymorphism is associated with serum uric acid (SUA) levels, we conducted a cross-sectional study in 321 healthy Japanese male subjects. In nonobese (body mass index, BMI<25) male subjects, interaction between ND2-237 Leu/Met genotypes and drinking frequency on SUA levels was observed (P=0.031). The SUA levels were significantly higher in daily drinkers with ND2-237Leu than in non-daily drinkers with ND2-237Leu (P=0.018). In nonobese men, after adjustment for covariates, daily drinkers with ND2-237Leu had a significantly higher odds ratio (OR) for hyperuricemia (SUA> or =6.5 mg/dl: vs. daily drinkers with ND2-237Met, OR=3.26, 95% confidence interval (CI) 1.14-9.29; vs. non-daily drinkers with ND2-237Leu, OR=3.22, 95% CI 1.39-7.45; SUA> or =7.0 mg/dl: vs. non-daily drinkers with ND2-237Met, OR=3.53, 95% CI 1.00-12.4). However, in obese (BMI> or =25) men, no significant interaction between ND2-237 Leu/Met polymorphism and habitual drinking on SUA levels or on the risk for hyperuricemia was observed. These results suggest that ND2-237 Leu/Met polymorphism modulates the effects of daily alcohol consumption on SUA levels in nonobese Japanese men.

Serum uric acid as an obesity-related indicator in early adolescence

In adults, serum uric acid levels are positively correlated with body mass index (BMI) and hyperuricemia is considered to be a common lifestyle disorder related with obesity. However, the relation of serum uric acid levels with obesity has not been elucidated in children and adolescents. Serum uric acid levels were determined in 1,729 healthy children, consisted of 923 boys and 806 girls, aged 9.1 - 15.0 years. The incidence of hyperuricemia (defined as more than 7.0 mg/dl) in boys and girls were 8.8% and 0.6%, respectively. In 1,281 children out of all subjects, including 684 boys and 597 girls, height, weight, aspartate aminotransferase, and alanine aminotransferase were also determined and the correlations between serum uric acid levels and obesity were analyzed. BMI is popularly used as a standard indicator of obesity in adults. However, BMI increases without fat accumulation as children grow. In Japan, percentage of overweight (POW) is usually used as an alternative indicator for obesity. In general, children are evaluated as obesity, when POW is equal to or more than 20% (>or= 20%). Serum uric acid levels are positively correlated with obesity-related indicators, BMI and POW, in both boys and girls. Serum uric acid levels of the subjects with high POW (>or= 20%) are significantly higher than those of the subjects with low POW (< 20%) in both boys and girls. These results suggest that serum uric acid levels are significantly increased with obesity and could be used as one of obesity-related indicators even in early adolescence.

UV-induced generation of rare tautomers of allopurinol and 9-methylhypoxanthine — A matrix isolation FTIR study

Monomers of allopurinol and 9-methylhypoxanthine were studied using the matrix isolation technique combined with Fourier transform infrared spectroscopy. The oxo tautomeric forms of both compounds were found to dominate in freshly deposited low-temperature argon matrices. For 9-methylhypoxanthine, a small amount of the hydroxy tautomer was also detected in an Ar matrix before any irradiation. Upon exposure of the matrices to the UV (lambda>230 nm or lambda>270 nm) light, a proton transfer photoreaction converting the oxo forms of both compounds into the corresponding hydroxy tautomers occurred. Generation of conjugated ketenes as minor photoproducts was also observed. For 4(3H)-pyrimidinone (a model compound for both allopurinol and 9-methylhypoxanthine), photoreversibility of the UV-induced oxo --> hydroxy transformation was experimentally proven by direct observation of the back hydroxy --> oxo photoreaction. The substrates (oxo tautomers) and products (hydroxy tautomers) of the observed phototransformations were identified by comparison of their IR spectra with the spectra theoretically predicted at the DFT(B3LYP)/6-31++G(d,p) level. The IR bands in the experimental spectra were assigned to the calculated normal modes.

Hyperurikämie und Gicht

In our modern society hyperuricemia is one of the most frequent metabolism disturbances. So far, every fourth man and every tenth woman suffer from an asymptomatic or a symptomatic hyperuricemia named gout. Mostly, over nutrition and malnutrition as well as other secondary factors with a genetically determined renal secretion disturbance of uric acid lead to an increase of serum uric acid. By deposition of uric acid crystals in tissues with intermittent immunologic activation of inflammation cells a manifestation of gout can be seen. The clinical image of gout varies widely. It may manifest as acute or chronic arthritis, tophi on the skin, subcutaneous tissue and the skeletal system as well as urate nephropathy. To eliminate the consequences of hyperuricemia in the long term, apart from a thorough anamnesis of nutritional habits a general examination of metabolic parameters is necessary to exclude a metabolic syndrome and other causes for a secondarily caused hyperuricemia. As gout is very often primarily caused by a renal secretion disturbance of uric acid special diagnostics should be done. Basing on literature research and inclusion of experts opinions this article represents the therapeutically options in treatment of hyperuricemia and gout with their resulting side effects and contraindications.

Magnetic resonance imaging in the quantitative assessment of gouty tophi

Measurements of tophus size can be important in monitoring the course of gout therapy, as tophus resolution is proposed as one measure of success of treatment. This multicentre study assessed the intra- and interreader reproducibility of quantitative tophus volume measurements from magnetic resonance images (MRI) in subjects with palpable gouty tophi. Subjects first underwent radiographic imaging of a selected tophus followed by MRI before and at <or=5, 10 and 20-min after gadolinium administration. After choosing optimal parameters, subjects underwent pre- and postgadolinium-enhanced MRIs of a selected tophus on two occasions separated by 5-10 days. Unenhanced spin-echo images provided satisfactory tophi images and were less subject to interfering artefacts than gadolinium-enhanced gradient-echo images. Intrareader reproducibility was excellent, with no statistically significant difference in mean tophus volume between visits (mean difference - 0.05 +/- 0.97 cm3). A small but statistically significant difference in interreader mean tophus volume was detected (mean difference 0.89 +/- 2.05 cm3; p < 0.05). MRI can quantify tophus size in gout and deserves further comparison with other techniques for tophus size monitoring in assessing effects of gout therapy.

Correction of allopurinol dosing should be based on clearance of creatinine, but not plasma creatinine levels: another insight to allopurinol-related toxicity

BACKGROUND

Dosing of allopurinol should be corrected depending on renal function, but corrections based on either plasma creatinine (Pcr) or creatinine clearance (CrCl) have been suggested to be minimal standards of care.

METHODS

Data from a cohort database of 484 gouty patients were used to calculate estimated allopurinol doses using CrCl and estimation of the clearance of creatinine using the equation of Cockroft and Gault (CrCl-CG) if, as a hypothesis, a dosage of 300 mg/d would be prescribed in any patient with Pcr <2.0 mg/dL. Also, allopurinol-related toxicity previous to rheumatologic consultation, during previous allopurinol therapy, and the relationship between both and estimated allopurinol doses were reviewed.

RESULTS

The cutoff point of plasma creatinine <2 showed 13% sensitivity and 100% specificity to detect CrCl <50 mL/min. Correlation and agreement between CrCl and CrCl-CG were good, as was the correlation between corrected doses using CrCl and CrCl-CG. One third of patients with Pcr 1.0-1.5 mg/dL and 90% of those with Pcr 1.5-2.0 mg/dL would receive estimated doses over 400 mg/dL/d CrCl. Also, 10% and 34% would receive estimated doses over 600 mg/dL/d CrCl, respectively. Allopurinol-related toxicity previous to consultation (11%) was associated with estimated doses over 400 mg/dL/d CrCl and severe toxicity with estimated doses over 600 mg/dL/d CrCl. When patients were given doses corrected on CrCl, few side effects were observed during follow up (6.7%), and the only severe one was associated with corrected dose over 600 mg/d.

CONCLUSIONS

Dosage adjustment of allopurinol should be based on clearance of creatinine or estimation of glomerular filtration using the Cockcroft-Gault equation. Pcr is insensitive enough to detect renal function impairment so that patients may be placed at risk for overdosing side effects. Corrected doses over 600 mg/dL/d CrCl may be associated with increased risk of severe toxicity.

Pathophysiology, Clinical Presentation and Treatment of Gout

Gout is a common form of inflammatory arthritis that has been managed primarily in general medical practices for centuries. It appears that there has been an increasing prevalence of gout over the past decades, implying a growing public health burden. Accurate diagnosis and recognition of the various stages and manifestations of gout enable realistic goal setting for management. Recent evidence suggests new risk factors and potentially refutes others. Management of gout requires characterising and modifying risk factors and associated disorders, and commonly initiating drug therapy. Pharmacotherapy of gout includes the management of acute flares with anti-inflammatory agents such as NSAIDs and glucocorticoids and long-term treatment with urate-lowering drugs. Although pharmacotherapy is generally safe and effective, there are caveats and limitations to all gout therapies. Patient non-adherence and errors with the use of drugs for gout treatment are important factors leading to medical failures. With early intervention, careful monitoring and patient education, gout is a condition that can be managed very effectively. The advent of new drugs (such as febuxostat and urate oxidase [uricase]) and enhanced understanding of the pathogenesis of gout continue to improve our therapeutic options, particularly in a subset of patients with refractory disease and those who are intolerant to currently available medications.

Febuxostat compared with allopurinol in patients with hyperuricemia and gout

BACKGROUND

Febuxostat, a novel nonpurine selective inhibitor of xanthine oxidase, is a potential alternative to allopurinol for patients with hyperuricemia and gout.

METHODS

We randomly assigned 762 patients with gout and with serum urate concentrations of at least 8.0 mg per deciliter (480 micromol per liter) to receive either febuxostat (80 mg or 120 mg) or allopurinol (300 mg) once daily for 52 weeks; 760 received the study drug. Prophylaxis against gout flares with naproxen or colchicine was provided during weeks 1 through 8. The primary end point was a serum urate concentration of less than 6.0 mg per deciliter (360 micromol per liter) at the last three monthly measurements. The secondary end points included reduction in the incidence of gout flares and in tophus area.

RESULTS

The primary end point was reached in 53 percent of patients receiving 80 mg of febuxostat, 62 percent of those receiving 120 mg of febuxostat, and 21 percent of those receiving allopurinol (P<0.001 for the comparison of each febuxostat group with the allopurinol group). Although the incidence of gout flares diminished with continued treatment, the overall incidence during weeks 9 through 52 was similar in all groups: 64 percent of patients receiving 80 mg of febuxostat, 70 percent of those receiving 120 mg of febuxostat, and 64 percent of those receiving allopurinol (P=0.99 for 80 mg of febuxostat vs. allopurinol; P=0.23 for 120 mg of febuxostat vs. allopurinol). The median reduction in tophus area was 83 percent in patients receiving 80 mg of febuxostat and 66 percent in those receiving 120 mg of febuxostat, as compared with 50 percent in those receiving allopurinol (P=0.08 for 80 mg of febuxostat vs. allopurinol; P=0.16 for 120 mg of febuxostat vs. allopurinol). More patients in the high-dose febuxostat group than in the allopurinol group (P=0.003) or the low-dose febuxostat group discontinued the study. Four of the 507 patients in the two febuxostat groups (0.8 percent) and none of the 253 patients in the allopurinol group died; all deaths were from causes that the investigators (while still blinded to treatment) judged to be unrelated to the study drugs (P=0.31 for the comparison between the combined febuxostat groups and the allopurinol group).

CONCLUSIONS

Febuxostat, at a daily dose of 80 mg or 120 mg, was more effective than allopurinol at the commonly used fixed daily dose of 300 mg in lowering serum urate. Similar reductions in gout flares and tophus area occurred in all treatment groups.

Possible interactions of the endothelial constitutive nitric oxide synthase genotype with alcohol drinking and walking time for high serum uric acid levels among Japanese

A variable number of tandem repeat polymorphism located in intron 4 of the gene for endothelial constitutive nitric oxide synthase (ecNOS) is reported to be significantly associated with the nitric oxide level, which influences serum uric acid (SUA). To cast light on any association between the polymorphism and hyperuricemia, as well as gene-environment interactions, a cross-sectional study was conducted for 703 health checkup examinees (213 men and 490 women). The age-adjusted odds ratio (aOR) of hyperuricemia (> or =7 mg/dL) for ecNOS 4/4, 4/5, or 5/6 genotypes (non-5/5 group) as compared with the 5/5 genotype was 2.41 (95% confidence interval [CI], 1.09-5.30) in men. The aORs for drinking alcohol relative to never drinking were found to be 8.93 (95% CI, 1.02-78.16) among men with non-5/5 genotypes and 1.76 (95% CI, 0.59-5.26) for their 5/5 counterparts. Moreover, the aORs for heavy drinking (> or =50 mL/d) were 23.16 (95% CI, 2.14-250.35) and 2.48 (95% CI, 0.75-8.15), respectively. The interaction between the genotype and current drinking was 3.10 (95% CI, 0.45-21.41). The aORs for more than 30 minutes of daily walking relative to 30 minutes or less of daily walking were found to be 1.54 (95% CI, 0.40-5.95) among men with non-5/5 genotypes and 0.31 (95% CI, 0.12-0.81) for their 5/5 counterparts. The interaction between the genotype and more than 30 minutes of daily walking was 4.92 (95% CI, 0.95-25.64). This study indicated that the ecNOS variable number of tandem repeat polymorphism influences the SUA level in men. Although the interactions were not significant, alcohol intake may be more influential among men with non-5/5 genotypes and walking may be more effective among men with the 5/5 genotype. These findings would be informative for men with high SUA levels.

Febuxostat, a novel nonpurine selective inhibitor of xanthine oxidase: a twenty-eight-day, multicenter, phase II, randomized, double-blind, placebo-controlled, dose-response clinical trial examining safety and efficacy in patients with gout

OBJECTIVE

Gout affects approximately 1-2% of the American population. Current options for treating hyperuricemia in chronic gout are limited. The purpose of this study was to assess the safety and efficacy of febuxostat, a nonpurine selective inhibitor of xanthine oxidase, in establishing normal serum urate (sUA) concentrations in gout patients with hyperuricemia (>or=8.0 mg/dl).

METHODS

We conducted a phase II, randomized, double-blind, placebo-controlled trial in 153 patients (ages 23-80 years). Subjects received febuxostat (40 mg, 80 mg, 120 mg) or placebo once daily for 28 days and colchicine prophylaxis for 14 days prior to and 14 days after randomization. The primary end point was the proportion of subjects with sUA levels <6.0 mg/dl on day 28.

RESULTS

Greater proportions of febuxostat-treated patients than placebo-treated patients achieved an sUA level <6.0 mg/dl at each visit (P < 0.001 for each comparison). The targeted sUA level was attained on day 28 in 0% of those taking placebo and in 56% of those taking 40 mg, 76% taking 80 mg, and 94% taking 120 mg of febuxostat. The mean sUA reduction from baseline to day 28 was 2% in the placebo group and 37% in the 40-mg, 44% in the 80-mg, and 59% in the 120-mg febuxostat groups. Gout flares occurred with similar frequency in the placebo (37%) and 40-mg febuxostat (35%) groups and with increased frequency in the higher dosage febuxostat groups (43% taking 80 mg; 55% taking 120 mg). During colchicine prophylaxis, gout flares occurred less frequently (8-13%). Incidences of treatment-related adverse events were similar in the febuxostat and placebo groups.

CONCLUSION

Treatment with febuxostat resulted in a significant reduction of sUA levels at all dosages. Febuxostat therapy was safe and well tolerated.

HLA-B*5801 allele as a genetic marker for severe cutaneous adverse reactions caused by allopurinol

Allopurinol, a commonly prescribed medication for gout and hyperuricemia, is a frequent cause of severe cutaneous adverse reactions (SCAR), which include the drug hypersensitivity syndrome, Stevens-Johnson syndrome, and toxic epidermal necrolysis. The adverse events are unpredictable and carry significant morbidity and mortality. To identify genetic markers for allopurinol-SCAR, we carried out a case-control association study. We enrolled 51 patients with allopurinol-SCAR and 228 control individuals (135 allopurinol-tolerant subjects and 93 healthy subjects from the general population), and genotyped for 823 SNPs in genes related to drug metabolism and immune response. The initial screen revealed strong association between allopurinol-SCAR and SNPs in the MHC region, including BAT3 (encoding HLA-B associated transcript 3), MSH5 (mutS homolog 5), and MICB (MHC class I polypeptide-related sequence B) (P < 10(-7)). We then determined the alleles of HLA loci A, B, C, and DRB1. The HLA-B*5801 allele was present in all (100%) 51 patients with allopurinol-SCAR, but only in 20 (15%) of 135 tolerant patients [odds ratio 580.3 (95% confidence interval, 34.4-9780.9); corrected P value = 4.7 x 10(-24)] and in 19 (20%) of 93 of healthy subjects [393.51 (23.23-6665.26); corrected P value = 8.1 x 10(-18)]. HLA alleles A*3303, Cw*0302, and DRB1*0301 were in linkage disequilibrium and formed an extended haplotype with HLA-B*5801. Our results indicated that allopurinol-SCAR is strongly associated with a genetic predisposition in Han Chinese. In particular, HLA-B*5801 allele is an important genetic risk factor for this life-threatening condition.

The effect of alcoholic beverage type on hyperuricemia in Japanese male office workers

BACKGROUND

The association between alcohol consumption and risk of hyperuricemia has been pointed out. However, the potential difference in the risk of hyperuricemia according to types of alcoholic beverage has not been assessed.

METHODS

A cross-sectional survey was performed using data from 715 men who had regular medical examinations in their workplace in 2001. Subjects were interviewed using a questionnaire about their lifestyle including types of alcoholic beverages and quantity of alcohol consumed per day. Logistic regression analysis was performed to assess the relationship between the types of alcoholic beverage and high serum uric acid level.

RESULTS

Compared with subjects who did not drink alcohol, the odds ratio (OR) of hyperuricemia (serum uric acid = 7.0+ mg/dL) was 2.89 (95% confidence interval [CI]: 1.46-5.71) for subjects who consumed 50+ g/day of ethanol, and 2.64 (95% CI: 1.33-5.24) for subjects who consumed 25-49g/day. Compared with subjects who drank Japanese sake, subjects who drank beer (OR=1.24, 95% CI: 0.55-2.80) or shochu (OR=1.06, 95% CI: 0.44-2.51) did not have a statistically significant difference in risk for hyperuricemia.

CONCLUSION

These findings from a cross-sectional study of Japanese male office workers suggested that alcohol consumption is associated with an increased risk of hyperuricemia and that this increased risk does not vary according to the types of alcoholic beverage.

Stone disease in the Hmong of Minnesota: initial description of a high-risk population

BACKGROUND AND PURPOSE

The Hmong are an ethically distinct refugee population from the highlands of Laos. Metropolitan Minneapolis-St. Paul, Minnesota is home to the largest population of Hmong ( 40,000) outside Asia. A clinical impression that the Hmong have a high rate of uric acid stone disease was evaluated.

PATIENTS AND METHODS

A retrospective chart review was performed. All adult Hmong patients seen between January 1, 2000, and December 31, 2001, by a large urology group practice (N = 205) were compared with a similar number of non-Hmong patients (N = 204).

RESULTS

Of these patients, 94 Hmong (46%) and 23 non-Hmong (11%) patients had stone disease (P < 0.001). After addition of 75 non-Hmong stone patients to create a suitable comparison group, a total of 86 Hmong and 88 non-Hmong stone patients had complete records. Sex (57% v 60% male) and mean age (47.9 v 47.3 years) were similar. Staghorn calculi were found in 21 Hmong (24%) and 0 non-Hmong patients (P < 0.001). Surgical treatments differed between Hmong and non-Hmong (P = 0.004): SWL (16 v 35), ureteroscopy (24 v 29), percutaneous nephrolithotomy (19 v 7), and nephrectomy (5 v 0). Treatment for staghorn calculi was refused by 9 Hmong patients (43%). Stone composition was available in 40 Hmong and 39 non-Hmong. Uric acid (>10%) was found in 50% of Hmong and 10% of non-Hmong stones (P < 0.001).

CONCLUSIONS

Hmong patients who come to urologic attention tend to do so for stone disease and tend to have uric acid calculi. The frequent requirement for invasive therapy, including nephrectomy, in the Hmong is of concern.

Prevalence of Comorbid Conditions and Prescription Medication Use Among Patients With Gout and Hyperuricemia in a Managed Care Setting

BACKGROUND

: Comorbid disorders and multiple prescription drug use are common among patients with gout and/or hyperuricemia and may influence the clinical course and outcome of gout.

OBJECTIVE

: We wanted to document the conditions and associated medications in a large group of patients with gout in a managed care setting.

METHODS

: This study was a 2-year, retrospective, administrative claims analysis examining comorbid conditions and medication use among managed care enrollees with gout/hyperuricemia across the United States.

RESULTS

: Of the 9482 study subjects (82.1% men, mean age 52 years), 57.9% had hypertension, 45.3% had a lipid disorder, 32.5% had both conditions, and 19.9% had diabetes mellitus. During the 24-month follow-up period, subjects had 5 +/- 3.14 (mean +/- standard deviation) different comorbid conditions and filled prescriptions for of 11.0 +/- 7.90 different medications. The most commonly filled prescriptions included antihypertensive drugs, 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors (statins), and nonsteroidal antiinflammatory drugs (NSAIDs).

CONCLUSIONS

: The study indicates a high prevalence of both comorbid conditions and multiple medication use among managed care enrollees with gout and/or hyperuricemia. Heightened awareness of these associated disorders is important because they may warrant treatment of their own accord and often some modification of gout management. Drugs, particularly diuretics and prophylactic aspirin, could potentially contribute to the development of hyperuricemia and gout.

Recent trends of hyperuricemia and obesity in Japanese male adolescents, 1991 through 2002

The aim of the present study was to determine the change of serum uric acid (UA) levels in male adolescents and to characterize the relationship between UA levels and obesity or its related factors. This study was conducted in 17,155 students at enrollment in Okayama University from 1991 through 2002, in which the mean serum UA level as a whole was 5.64 +/- 0.009 mg/dL (mean +/- SEM) and the incidence of hyperuricemia (>/=7.6 mg/dL) was 4.13%. Serum UA levels were correlated with obesity-related indicators, including body mass index (BMI; r = 0.282, P <.0001) and skin-fold thickness (r = 0.286, P <.0001). The incidence of hyperuricemia was increased in parallel with BMI. In the last 4 years (1999 through 2002) of the study period, serum UA levels (5.76 mg/dL) and the incidence of hyperuricemia (4.5%) were significantly increased compared with those in the earlier period (1991 through 1994: 5.50 mg/dL and 3.5%, respectively). However, BMI has been rather gradually decreased throughout 12-year observation in all the subjects. Hyperuricemia was related to the presence of other risk factors, including hypercholesterolemia, liver function abnormality, and hypertension. The frequencies of such abnormalities were higher than euuricemic subjects and this trend was notable in the most recent students enrolled from 1999 through 2002. Hyperuricemia was even found in the group of non-obese male adolescents. Taking into consideration that hyperuricemia is associated with a high prevalence of lifestyle-related diseases in adults, it is of great importance to prevent hyperuricemia at the early stage in Japanese adolescents.

Primary prevention in rheumatology: the importance of hyperuricemia

Hyperuricemia (HU) is present in 5-30% of the general population, although the prevalence is higher among some ethnic groups and seems to be increasing worldwide. Classically, chronic HU has been considered a risk factor for gout or lithiasis and is associated with alcoholism, obesity, hypertension, dyslipidemia, hyperglycemia/diabetes mellitus, renal failure and intake of certain drugs. HU is also associated with cardiovascular diseases such as hypertension, vascular disease, pre-eclampsia, pulmonary arterial hypertension, stroke, heart failure, ischemic heart disease and also metabolic syndrome, renal disease and increased mortality. It is uncertain if these associations are dependent or not, especially cardiovascular and renal diseases. Patients with chronic HU and also those with gout require both medical investigation for associated diseases or drugs as well as nutritional counseling and life-style changes. HU should alert physicians to possible complications.

A literature review of the epidemiology and treatment of acute gout

BACKGROUND

Gout is the most common cause of inflammatory arthritis in men aged >40 years and is frequently encountered in clinical practice.

OBJECTIVE

The goal of this article was to review the published literature on the epidemiology, treatment, and estimated burden of illness of acute gout.

METHODS

Articles on gout published in English between 1980 and June 2002 were identified through a MEDLINE search. Relevant clinical studies and review articles were found using the text- and keyword-search term gout alone and in combination with epidemiology, prevalence, incidence, complications, outcome, quality of life, economics, cost, prevention or drug therapy. The reference lists of identified articles, especially review articles, were checked for any additional studies that might have been missed in the original MEDLINE search.

RESULTS

The epidemiology of gout in various geographic regions has been well documented. Data suggest that environmental, racial, and hereditary factors may influence the development of gout, and that the prevalence of gout appears to be on the rise worldwide. Evidence from well-designed clinical studies evaluating drug therapies for gout is limited. Therapies for acute gout include corticotropin, corticosteroids, colchicine or, more often, nonsteroidal anti-inflammatory drugs (NSAIDs), which have shown comparable efficacy. A recent study suggests that etoricoxib, a new cyclooxygenase-2-selective inhibitor, may be as effective as and better tolerated than traditional NSAIDs in the treatment of gout. Urate-lowering therapy, prophylactic colchicine, and low-dose NSAIDs are used for the long-term prophylaxis of gout. However, all acute and prophylactic therapies are associated with adverse events. Using an economic model for gout, the annual direct burden of illness for new cases of acute gout can be estimated at 27,378,494 US dollars in the United States.

CONCLUSIONS

Gout is an increasingly prevalent condition worldwide and creates a heavy economic burden. Available treatments are generally effective; however, they are not devoid of adverse events. Well-designed, long-term, controlled clinical trials evaluating the comparative efficacy and tolerability of treatments for gout are needed.