Prevalence of gout and hyperuricemia in the US general population: the National Health and Nutrition Examination Survey 2007-2008

Long-term safety of pegloticase in chronic gout refractory to conventional treatment

Objective

To evaluate the long-term safety (up to 3 years) of treatment with pegloticase in patients with refractory chronic gout.

Methods

This open-label extension (OLE) study was conducted at 46 sites in the USA, Canada and Mexico. Patients completing either of two replicate randomised placebo-controlled 6-month trials received pegloticase 8 mg every 2 weeks (biweekly) or every 4 weeks (monthly). Safety was evaluated as the primary outcome, with special interest in gout flares and infusion-related reactions (IRs). Secondary outcomes included urate-lowering and clinical efficacy.

Results

Patients (n=149) received a mean±SD of 28±18 pegloticase infusions and were followed for a mean of 25±11 months. Gout flares and IRs were the most frequently reported adverse events; these were least common in patients with a sustained urate-lowering response to treatment and those receiving biweekly treatment. In 10 of the 11 patients with a serious IR, the event occurred when uric acid exceeded 6 mg/dl. Plasma and serum uric acid levels remained <6 mg/dl in most randomised controlled trial (RCT)-defined pegloticase responders throughout the OLE study and were accompanied by sustained and progressive improvements in tophus resolution and flare incidence.

Conclusions

The safety profile of long-term pegloticase treatment was consistent with that observed during 6 months of RCT treatment; no new safety signals were identified. Improvements in clinical status, in the form of flare and tophus reduction initiated during RCT pegloticase treatment in patients maintaining goal range urate-lowering responses were sustained or advanced during up to 2.5 years of additional treatment.

The rheumatology of gout

Gout is a metabolic disorder of purine metabolism with primary manifestations of acute and chronic arthritis and tophus formation. The prevalence of gout appears to be increasing and may affect up to 8 million people in the United States. The development of novel therapies for gout after a 40-year hiatus has opened new understanding of this disease. In addition to causing severe musculoskeletal pain, gout is associated with impaired quality of life, reduced functional status, and injury to joints. The quality of care for many patients with gout is unfortunately not in keeping with current guidelines. The approval of new therapies to treat hyperuricemia, such as febuxostat and pegloticase, has increased our knowledge of the challenges of adequately controlling the disease. Rather than providing a comprehensive overview of gout, this review focuses on new developments in the clinical aspects of gout and highlights advances in the drug therapy of gout.

Tophi and frequent gout flares are associated with impairments to quality of life, productivity, and increased healthcare resource use: Results from a cross-sectional survey

Background

The prevalence of gout is increasing, and most research on the associated burden has focused on serum urate (sUA) levels. The present study quantifies the impact of the presence of tophi and frequency of acute gout attacks on health-related quality of life (HRQOL), productivity, and healthcare resource utilization.

Methods

Patients with self-reported gout (n = 620; 338 in US and 282 across France, Germany, and UK) were contacted based on inclusion in the 2010 US and EU National Health and Wellness Surveys (Kantar Health) and the Lightspeed Research ailment panel. Respondents were categorized into mutually-exclusive groups based on number of gout flares experienced in the past 12 months (0/don’t recall, 1–2, 3, 4–5, 6+), current presence of tophi (none, 1+, or not sure), and sUA level awareness (yes, no). HRQOL (SF-12v2), healthcare provider visits in the last 6 months, and work productivity and activity impairment (WPAI) were compared across groups.

Results

Most patients were males, mean age of 61 years, who reported experiencing at least one acute gout flare in the past 12 months, and 12.3% (n = 76) reported presence of tophi. Among the 27.7% (n = 172) of patients who were aware of their sUA levels, higher sUA was associated with more flares and tophi. Decreased HRQOL was associated with more frequent flares and presence of tophi. In multivariable models predicting outcomes based on presence of tophi and number of flares, both flares (≥4) and tophi (≥1) were associated with HRQOL decrements on physical and mental component summary scores and health utilities (all p < 0.05), after adjustment for age, gender, and time since diagnosis. Flares were also associated with greater activity impairment.

Conclusions

Impairments associated with gout flares and presence of tophi, across patients in the US and EU, underscore the importance of effective management of this potentially curable condition.

Prescription and dosing of urate-lowering therapy, rather than patient behaviours, are the key modifiable factors associated with targeting serum urate in gout

Background

Long term serum urate (SU) lowering to a target of <0.36 mmol/l (6 mg/dl) is recommended for effective gout management. However, many studies have reported low achievement of SU targets. The aim of this cross-sectional study was to examine the clinical and psychological factors associated with SU targets in patients with gout.

Methods

Patients with gout for <10 years were recruited from primary and secondary care settings. SU target was defined as SU concentration <0.36 mmol/L at the time of the study visit. Both clinical and psychological factors associated with SU target were analysed. The relationship between SU target and measures of gout activity such as flare frequency, tophi, work absences, and Health Assessment Questionnaire-II was also analysed.

Results

Of the 273 patients enrolled into the study, 89 (32.6%) had SU concentration <0.36 mmol/L. Urate-lowering therapy (ULT) use was strongly associated with SU target (p < 0.001). In those patients prescribed ULT (n = 181), allopurinol dose, patient confidence to keep SU under control, female sex, and ethnicity were independently associated with SU target. Other patient psychological measures and health-related behaviours, including adherence scores, were not independently associated with SU target in those taking ULT. Creatinine clearance, diuretic use, age, and body mass index were not associated with SU target. Patients at SU target reported lower gout flare frequency, compared with those not at target (p = 0.03).

Conclusions

ULT prescription and dosing are key modifiable factors associated with achieving SU target. These data support interventions focusing on improved use of ULT to optimise outcomes in patients with gout.

Safety of urate-lowering therapies: managing the risks to gain the benefits

Gout is a metabolic disorder of purine metabolism and uric acid elimination. Over time, acute gout can develop into a chronic, disabling arthropathy, often associated with multiple comorbidities. Gout patients have often been undertreated, partly because of the clinician's perceived risks of a therapy outweighing its potential benefits. The approval of new therapies to treat hyperuricemia in gout has led to a new understanding of gout management and medication safety regarding new and old therapies. This review focuses on potential safety issues of currently available urate-lowering therapies and outlines strategies to minimize risks so their benefits can be reached.

Adherence to uric acid treatment guidelines in a rheumatology clinic

The aim of this study was to evaluate adherence to recommended serum uric acid levels in the rheumatology outpatients department of a university teaching hospital. We performed a retrospective study of all patients with a definitive diagnosis of gout attending our subspecialty gout clinic between 1 January 2010 and 31 December 2010. We evaluated adherence with two recently suggested uric acid thresholds, <300 μmol/L (<5 mg/dL) and <360 μmol/L (<6 mg/dL). Patient management was judged to adhere to the guidelines if either (1) the latest serum uric acid level was less than the specified guideline targets or (2) uric acid-lowering therapy was titrated upwards or the agent changed if the serum uric acid was above the guideline targets. One hundred two patients with a definitive diagnosis of gout attended the outpatients department between 1 January 2010 and 31 December 2010 and were included in the study. Median serum uric acid level was 331 μmol/L (IQR 276-456 μmol/L). Eighty-six patients (84 %) were treated with allopurinol, six patients (6 %) were treated with febuxostat (one of whom also received probenecid), and one with rasburicase. In 80 patients (78 %), the management adhered to a target guideline of <360 μmol/L (<6 mg/dL). In 66 patients (65 %), the management adhered to a target guideline of <300 μmol/L (<5 mg/dL). A treat-to-target approach has the potential to improve patient outcomes in the management of gouty arthritis. Our study shows encouraging results with the majority of patients on appropriate therapy and reaching recommended targets.

Uric acid as a danger signal in gout and its comorbidities

Uric acid is a waste product of purine catabolism. This molecule comes to clinical attention when it nucleates to form crystals of monosodium urate (MSU) in joints or other tissues, and thereby causes the inflammatory disease of gout. Patients with gout frequently suffer from a number of comorbid conditions including hypertension, diabetes mellitus and cardiovascular disease. Why MSU crystals trigger inflammation and are associated with comorbidities of gout has been unclear, but recent studies provide new insights into these issues. Rather than simply being a waste product, uric acid could serve a pathophysiological role as a local alarm signal that alerts the immune system to cell injury and helps to trigger both innate and adaptive immune responses. The inflammatory component of these immune responses is caused when urate crystals trigger both inflammasome-dependent and independent pathways to generate the proinflammatory cytokine IL-1. The resulting bioactive IL-1 stimulates the inflammation of gout and might contribute to the development of other comorbidities. Surprisingly, the same mechanisms underlie the inflammatory response to a number of irritant particles, many of which also cause disease. These new insights help to explain the pathogenesis of gout and point to potential new therapeutic targets for this and other sterile inflammatory diseases.

The genetics of hyperuricaemia and gout

Gout is a common and very painful inflammatory arthritis caused by hyperuricaemia. This review provides an update on the genetics of hyperuricaemia and gout, including findings from genome-wide association studies. Most of the genes that associated with serum uric acid levels or gout are involved in the renal urate-transport system. For example, the urate transporter genes SLC2A9, ABCG2 and SLC22A12 modulate serum uric acid levels and gout risk. The net balance between renal urate absorption and secretion is a major determinant of serum uric acid concentration and loss-of-function mutations in SLC2A9 and SLC22A12 cause hereditary hypouricaemia due to reduced urate absorption and unopposed urate secretion. However, the variance in serum uric acid explained by genetic variants is small and their clinical utility for gout risk prediction seems limited because serum uric acid levels effectively predict gout risk. Urate-associated genes and genetically determined serum uric acid levels were largely unassociated with cardiovascular-metabolic outcomes, challenging the hypothesis of a causal role of serum uric acid in the development of cardiovascular disease. Strong pharmacogenetic associations between HLA-B*5801 alleles and severe allopurinol-hypersensitivity reactions were shown in Asian and European populations. Genetic testing for HLA-B*5801 alleles could be used to predict these potentially fatal adverse effects.

Imaging in gout: insights into the pathological features of disease

PURPOSE OF REVIEW

Imaging has the potential to assess various pathological manifestations of gout, including monosodium urate (MSU) crystal deposition, tophus formation and cartilage, soft tissue, and bone pathology. This review discusses recent research examining the role of imaging to assess the manifestations of disease.

RECENT FINDINGS

Various imaging techniques are used in the assessment of gout, including plain radiography, ultrasonography, conventional computed tomography (CT), dual energy computed tomography (DECT), and MRI. Potential roles for ultrasonography are MSU crystal detection, measurement of tophi, and assessment of disease complications. Ultrasonography may allow detection of MSU crystals in patients with hyperuricaemia, prior to development of clinically apparent gout. Conventional CT allows excellent visualization of tophi and bone erosion. DECT is a promising method of noninvasive MSU crystal detection. MRI allows assessment of tophi, synovial and soft tissue disease, and bone pathology. The relative absence of MRI bone marrow oedema in gout suggests that the mechanisms of bone erosion in gout are quite different from those in other erosive arthropathies.

SUMMARY

Imaging modalities have provided important insights into the pathology of gout. The role of various imaging techniques in gout diagnosis, monitoring, and prediction of outcome is rapidly developing.

Independent association of serum retinol and β-carotene levels with hyperuricemia: A national population study

OBJECTIVE

Uses of synthetic vitamin A derivatives (e.g., isotretinoin used for severe acne) and high doses of preformed vitamin A have been implicated in the pathogenesis of hyperuricemia and gout, whereas a trial reported that β-carotene may lower serum uric acid (UA) levels. We evaluated the potential population impact of these factors on serum UA in a nationally representative sample of US adults.

METHODS

Using data from 14,349 participants ages ≥20 years in the Third National Health and Nutrition Examination Survey (1988-1994), we examined the relationship between serum retinol, β-carotene, and UA levels using weighted linear regression. Additionally, we examined the relationship with hyperuricemia using weighted logistic regression.

RESULTS

Serum UA levels increased linearly with increasing serum retinol levels, whereas serum UA levels decreased with increasing serum β-carotene levels. After adjusting for age, sex, dietary factors, and other potential confounders, the serum UA level differences from the bottom (referent) to the top quintiles of serum retinol levels were 0, 0.16, 0.32, 0.43, and 0.71 mg/dl (P for trend <0.001), and for β-carotene were 0, -0.15, -0.29, -0.27, and -0.40 mg/dl (P for trend <0.001), respectively. Similarly, the multivariate odds ratios of hyperuricemia from the bottom (referent) to top quintiles of serum retinol levels were 1.00, 1.30, 1.83, 2.09, and 3.22 (P for trend <0.001) and for β-carotene were 1.00, 0.85, 0.68, 0.73, and 0.54 (P for trend <0.001), respectively. The graded associations persisted across subgroups according to cross-classification by both serum retinol and β-carotene levels.

CONCLUSION

These nationally representative data raise concerns that vitamin A supplementation and food fortification may contribute to the high frequency of hyperuricemia in the US population, whereas β-carotene intake may be beneficial against hyperuricemia. The use of β-carotene as a novel preventive treatment for gout deserves further investigation.

Relationship between serum uric acid and internal carotid resistive index in hypertensive women: a cross-sectional study

Background

The impact of serum uric acid (SUA) on arteries of hypertensive subjects remains to be fully established. This study investigated the relationship between SUA and carotid structural and hemodynamic parameters in hypertensive men and women.

Methods

Three hundred and thirty eight patients (207 women and 131 men) were cross-sectionally evaluated by clinical, laboratory, hemodynamic and carotid ultrasound analysis. Common carotid diameters, circumferential wall tensions, Young’s Elastic Modulus, Stiffness Index, Arterial Compliance and intima-media thickness (IMT) were determined. Internal carotid artery resistive index (ICRI), a hemodynamic measure that reflects local vascular impedance and microangiopathy, was also assessed.

Results

Univariate analysis showed no significant correlation of SUA with carotid diameters, elasticity/stiffness indexes, IMT and circumferential wall tensions in both genders. Conversely, SUA correlated with ICRI (r = 0.34; p < 0.001) in women, but not in men, and hyperuricemic women presented higher ICRI than normouricemic ones (0.684 ± 0.007 vs. 0.649 ± 0.004; p < 0.001). Stepwise and logistic regression analyses adjusted for potential confounding factors showed that ICRI was independently associated with SUA and hyperuricemia in women.

Conclusions

This study demonstrated that SUA was associated with ICRI in hypertensive women, suggesting that there might gender-related differences in the relationship between SUA and vascular damage in subjects with systemic hypertension.

Comorbidities of gout and hyperuricemia in the US general population: NHANES 2007-2008

PURPOSE

The objective of this study was to estimate the latest prevalence of major comorbidities associated with gout and hyperuricemia in the US based on a recent, nationally representative sample of US men and women.

METHODS

Using data from 5707 participants aged 20 years and older in the National Health and Nutrition Examination Survey 2007-2008, we calculated the national prevalence and population estimates of major comorbidities according to gout status and various hyperuricemia levels, compared with those without these conditions. Case definitions of gout and comorbidities were based on an affirmative answer to a question that asked whether a physician or a health professional had diagnosed the corresponding condition.

RESULTS

Among these individuals with gout, 74% (6.1 million) had hypertension, 71% (5.5 million) had chronic kidney disease stage ≥2, 53% (4.3 million) were obese, 26% (2.1 million) had diabetes, 24% (2.0 million) had nephrolithiasis, 14% (1.2 million) had myocardial infarction, 11% (0.9 million) had heart failure, and 10% (0.9 million) had suffered a stroke. These proportions were substantially higher than those among individuals without gout (all P-values <.67). With increasing levels of hyperuricemia, there were graded increases in the prevalences of these comorbidities. In the top category (serum urate ≥10 mg/dL), 86% of subjects had chronic kidney disease stage ≥2, 66% had hypertension, 65% were obese, 33% had heart failure, 33% had diabetes, 23% had myocardial infarction, and 12% had stroke. These prevalences were 3-33 times higher than those in the lowest serum urate category (<4 mg/dL). Sex-specific odds ratios tended to be larger among women than men, and the overall comorbidity prevalence was highest among individuals with both gout and hyperuricemia.

CONCLUSIONS

These findings from the latest nationally representative data highlight remarkable prevalences and population estimates of comorbidities of gout and hyperuricemia in the US. Appropriate preventive and management measures of these comorbidities should be implemented in gout management, with a preference to strategies that can improve gout and comorbidities together.

Are dosing adjustments required for colchicine in the elderly compared with younger patients?

INTRODUCTION

The objective of this study was to compare the relative bioavailability of the US Food and Drug Administration-approved formulation of colchicine after a single 0.6 mg dose in young (18-30 years of age) and elderly (≥60 years of age) healthy subjects to determine whether dosing adjustments are required in elderly patients.

METHODS

A single-dose, single-drug, parallel-group study was performed in 20 young subjects with normal renal function (defined as creatinine clearance [CrCl] ≥80 mL/min) and 18 elderly subjects with normal or mild renal impairment (CrCl ≥50 mL/min) in otherwise good health. Blood samples were collected for up to 72 hours postdose and analyzed for colchicine using a validated liquid chromatography/tandem mass spectrometry method. Noncompartmental pharmacokinetic parameters were compared using analysis of variance methods.

RESULTS

There were no statistically significant (P < 0.05) differences in mean colchicine pharmacokinetic parameters between young and elderly subjects, including peak plasma concentration (C(max)) (2.53 vs. 2.56 ng/mL), time to C(max) (1.25 vs. 1.25 hours), area under the plasma concentration-time curve to infinity (22.29 vs. 25.01 ng/h/mL), elimination half-life (25.4 vs. 30.1 hours), oral clearance (0.40 vs. 0.35 L/h/kg), and apparent volume of distribution (14.3 vs. 14.8 L/kg), respectively.

CONCLUSION

The lack of any significant differences in colchicine pharmacokinetic parameters between young and elderly healthy subjects, with some of the latter including mild renal impairment, suggests that dose modification of colchicine may not be necessary in healthy elderly patients. However, when evaluating the use of colchicine dosing in an elderly patient, the confounding effect on overall exposure and safety from comorbid conditions, the use of concomitant medications, and the administration of multiple doses should be considered.

Purine-rich foods intake and recurrent gout attacks

OBJECTIVE

To examine and quantify the relation between purine intake and the risk of recurrent gout attacks among gout patients.

METHODS

The authors conducted a case-crossover study to examine associations of a set of putative risk factors with recurrent gout attacks. Individuals with gout were prospectively recruited and followed online for 1 year. Participants were asked about the following information when experiencing a gout attack: the onset date of the gout attack, clinical symptoms and signs, medications (including antigout medications), and presence of potential risk factors (including daily intake of various purine-containing food items) during the 2-day period prior to the gout attack. The same exposure information was also assessed over 2-day control periods.

RESULTS

This study included 633 participants with gout. Compared with the lowest quintile of total purine intake over a 2-day period, OR of recurrent gout attacks were 1.17, 1.38, 2.21 and 4.76, respectively, with each increasing quintile (p for trend <0.001). The corresponding OR were 1.42, 1.34, 1.77 and 2.41 for increasing quintiles of purine intake from animal sources (p for trend <0.001), and 1.12, 0.99, 1.32 and 1.39 from plant sources (p=0.04), respectively. The effect of purine intake persisted across subgroups by sex, use of alcohol, diuretics, allopurinol, NSAIDs and colchicine.

CONCLUSIONS

The study findings suggest that acute purine intake increases the risk of recurrent gout attacks by almost fivefold among gout patients. Avoiding or reducing amount of purine-rich foods intake, especially of animal origin, may help reduce the risk of gout attacks.

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.

Nature versus nurture in gout: a twin study

BACKGROUND

Gouty arthritis (gout) is the most common inflammatory arthritis in the United States and several other countries. Some rare forms of gout have a known genetic basis, but the relative importance of genetic factors on the risk for the lifetime prevalence of gout is not clear.

METHODS

We performed a heritability analysis for hyperuricemia and gout among 514 unselected, all-male twin pairs who were a part of the National Heart, Lung, and Blood Institute twin study, a prospective observational cohort study. Statistical analyses were performed using structural equation models and maximum likelihood methods. The covariates used for adjustment in the structural equation models were identified using bivariate logistic regressions.

RESULTS

The study population included 253 monozygotic (MZ) and 261 dizygotic (DZ) twin pairs, aged 48 (±3) years at baseline and followed for a mean of 34 years. The lifetime prevalence of gout did not differ between MZ and DZ twins. The concordance of hyperuricemia was 53% in MZ and 24% in DZ twin pairs (P<.001). Models that quantified the relative contribution of genetic and environmental factors on phenotypic variance showed that individual variability in gout was substantially influenced by environmental factors shared between co-twins and not by genetic factors. In contrast, individual differences in hyperuricemia were influenced significantly by genetic factors.

CONCLUSION

Hyperuricemia is a genetic trait. Outside the context of rare genetic disorders, risk for gout is determined by the environment. This has implications for prevention and treatment approaches.

Treatment of chronic gouty arthritis: it is not just about urate-lowering therapy

OBJECTIVES

The management of gouty arthritis is focused on treating pain and inflammation associated with acute flares and preventing further acute flares and urate crystal deposition. A challenge associated with the successful management of gouty arthritis is an increased risk of acute flares during the first months after initiation of urate-lowering therapy (ULT). This increase in flare frequency can occur regardless of the choice of ULT and is linked to suboptimal patient adherence to ULT. Current treatment recommendations for the use of prophylaxis are limited. There are no definitive recommendations as to which agents should be used or for how long therapy is beneficial after starting ULT. This article aims to improve awareness of the importance of gouty arthritis flare prophylaxis when initiating ULT and to summarize current recommendations and clinical findings related to the efficacy and safety of currently available and investigational new therapies.

METHODS

This review discusses the pathophysiology of acute gouty arthritis flares during initiation of ULT and examines the literature on the use of anti-inflammatory prophylaxis for reduction of these flares.

RESULTS

It has recently become clear that, even when the patient is asymptomatic, chronic inflammation is often present in patients with chronic gouty arthritis. Chronic anti-inflammatory therapy should therefore be added to chronic ULT. Prophylaxis with colchicine as well as with nonsteroidal anti-inflammatory drugs (NSAIDs) during ULT initiation can reduce the incidence and severity of gouty arthritis flares substantially; however, safety concerns associated with colchicine and NSAIDs may limit their use.

CONCLUSION

When colchicine and NSAIDs are contraindicated or poorly tolerated, rilonacept and canakinumab, interleukin-1 inhibitors in trials, may prove to be useful alternatives for flare prevention. (Of note, although both inhibit the IL-1β pathway, rilonacept also binds to IL-1α and IL-1RA, in contrast to canakinumab, which binds selectively to IL-1β.).

Correlates of Axial Gout: A Cross-sectional Study

Objective.

A cross-sectional study was undertaken to determine the prevalence of axial gout in patients with established gouty arthritis and to analyze clinical, laboratory, and radiological correlations.

Methods.

Forty-eight subjects with a history of gouty arthritis (American College of Rheumatology criteria) for ≥ 3 years under poor control were included. Subjects underwent history, physical examination, laboratory testing, and imaging studies, including radiographs of the hands and feet and computerized tomography (CT) of the cervical and lumbar spines and sacroiliac joints (SIJ). Patients with characteristic erosions and/or tophi in the spine or SIJ were considered to have axial or spinal gout.

Results.

Seventeen patients (35%) had CT evidence of spinal erosions and/or tophi, with tophi identified in 7 of the 48 subjects (15%). The spinal location of axial gout was cervical in 7 patients (15%), lumbar in 16 (94%), SIJ in 1 (6%), and more than 1 location in 14 (82%). Duration of gout, presence of back pain, and serum uric acid levels did not correlate with axial gout. Extremity radiographs characteristic of gouty arthropathy found in 21 patients (45%) were strongly correlated with CT evidence of axial gout (p < 0.001). All patients with tophi in the spine had abnormal hand or feet radiographs (p = 0.005).

Conclusion.

Axial gout may be a common feature of chronic gouty arthritis. The lack of correlation with back pain, the infrequent use of CT imaging in patients with back pain, and the lack of recognition of the problem of spinal involvement in gouty arthritis suggest that this diagnosis is often missed.

Systematic review of the prevalence of gout and hyperuricaemia in Australia

AIMS

Gout is a growing health problem worldwide especially in affluent countries, such as Australia. Gout and hyperuricaemia are associated with the metabolic syndrome, diabetes mellitus, obesity and hypertension. More importantly, Australia has a growing prevalence of these important health problems. The aim of this study was to systematically review published information regarding the prevalence of gout and hyperuricaemia in Australia.

METHODS

A systematic search was undertaken of the MEDLINE, EMBASE and Web of Science databases, as well as relevant websites for journal articles and reports relating to the prevalence of hyperuricaemia and gout in Australia.

RESULTS

Twenty-five journal articles and five reports were included in the review. Data collected in a standardised way show gout increased in prevalence from 0.5% population prevalence to 1.7% population prevalence from 1968 to 1995/1996. There has been a significant rise in the prevalence of gout in the Australian Aboriginal population from 0% in 1965 to 9.7% in men and 2.9% in women in 2002. Consistent with the rise in gout prevalence, serum uric acid in blood donors has increased from 1959 to 1980 (17% in 30- to 40-year-old men).

CONCLUSIONS

The rate of gout and hyperuricaemia in Australia is high in relation to comparable countries and is increasing. The prevalence of gout in elderly male Australians is second only to New Zealand, which has the highest reported rate in the world. Further research on Aboriginal and Torres Strait Islander gout and hyperuricaemia is required as a result of the lack of contemporary data.

Evaluation of health care costs and utilization patterns for patients with gout

BACKGROUND

The prevalence of gout has been increasing. Serum uric acid (sUA) levels ≥6 mg/dL have been associated with high morbidity and increased health care utilization.

OBJECTIVE

To assess the costs and patterns of health care resource utilization for patients with gout, categorized into 3 cohorts based on sUA levels.

METHODS

We retrospectively analyzed laboratory, pharmacy, and medical service claims data (January 2005 to June 2010) for patients ≥18 years old. Inclusion criteria were at least 2 sUA levels and at least 1 primary gout diagnosis (International Classification of Disease-9th revision code 274.xx), and/or at least 1 prescription for gout-specific medications. Outcomes including costs, health care resource utilization, and medication adherence and persistence were assessed for the 1-year postindex period and summarized for the 3 cohorts based on sUA levels: <6 mg/dL, 6 to 8.99 mg/dL, and ≥9 mg/dL. Costs were adjusted based on preindex utilization and baseline characteristics.

RESULTS

Three hundred fifty-two patients met the inclusion criteria: cohort 1 (sUA <6 mg/dL), n = 38, mean age 59 years; cohort 2 (sUA 6-8.99 mg/dL), n = 231, mean age 61 years; and cohort 3 (sUA ≥9 mg/dL), n = 83, mean age 62 years. Mean adjusted gout-related health care costs were $332, $353, and $663, respectively (P <0.05); mean adjusted all-cause health care costs were $11,365, $11,551, and $14,474, respectively, for the 3 cohorts (P <0.05). sUA levels were positively associated with the percent of patients who had at least 1 hospitalization and the mean number of hospitalizations and emergency department visits (P < 0.05). Significantly more patients with sUA <6 mg/dL achieved adherence rates of ≥80% and had a longer mean duration of continuous treatment compared with patients with sUA between 6 and 8.99 mg/dL or ≥9.0 mg/dL (P <0.05).

CONCLUSIONS

Patients with high levels of sUA had higher gout-related and all-cause health care costs, more all-cause hospitalizations, and emergency department visits, but they also exhibited poorer adherence and persistence.

[The etiology and management of gout]

Gout is an inflammatory arthritis caused by monosodium urate (MSU) crystal deposits in and around the joint. The formation of urinary calculi can also occur in gout, but are less common than arthritis. Gout usually presents with recurrent episodes of joint inflammation, which over time lead to tophus formation and joint destruction. In the last decade, significant advances have been made regarding not only the epidemiology and genetics of gout and hyperuricemia but also the mechanisms of inflammation and treatment of gout. In addition, knowledge concerning the key role of interleukin 1 (IL-1) has provided new therapeutic perspectives. However, the current management of gout is often suboptimal, with many Patienten either not receiving adequate treatment or being unable to tolerate existing treatments. New therapeutic agents provide interesting new options for Patienten with difficult-to-treat gouty arthritis.The English full-text version of this is available at SpringerLink (under "Supplemental").

Can racial disparities in optimal gout treatment be reduced? Evidence from a randomized trial

There is a disproportionate burden of gout in African-Americans in the U.S. due to a higher disease prevalence and lower likelihood of receiving urate-lowering therapy (ULT), compared to Caucasians. There is an absence of strong data as to whether the response to ULT differs by race/ethnicity. BMC Musculoskeletal Disorders recently published a secondary analyses of the CONFIRMS trial, a large randomized controlled, double-blind trial of 2,269 gout patients. The authors reported that the likelihood of achieving the primary study efficacy end-point of achieving serum urate<6 mg/dl was similar between African-Americans and Caucasians, for all three treatment arms (Febuxostat 40 mg and 80 mg and allopurinol 300/200 mg). More importantly, rates were similar in subgroups of patients with mild or moderate renal insufficiency. Adverse event rates were similar, as were the rates of gout flares. These findings constitute a convincing evidence to pursue aggressive ULT in gout patients, regardless of race/ethnicity. This approach will likely help to narrow the documented racial disparities in gout care. Please see related article: http://www.biomedcentral.com/1471-2474/13/15.

Gout, genetics and ABC transporters

Gout is a chronic arthritic disease associated with high levels of urate in blood. Recent advances in research have permitted the identification of several new and common genetic factors underlying the disease. Among them, a polymorphism in the ABC transporter gene ATP-binding cassette transporter isoform G2 has been highlighted. ATP-binding cassette transporter isoform G2 was found to be involved in renal urate elimination, and the presence of the Q141K polymorphism to induce a 2-fold decrease in urate efflux. The Q141K variant has been shown to have impaired trafficking, leading to its intracellular retention, whereas the wild type protein is expressed on the cell surface. Several agents are being studied for the purpose of improving folding, trafficking and function of various ABC transporters, including ATP-binding cassette transporter isoform G2. If successful, this strategy opens doors to potential new therapies for gout.

2011 recommendations for the diagnosis and management of gout and hyperuricemia

Gout is a major health problem in the United States; it affects 8.3 million people, which is approximately 4% of the adult population. Gout is most often diagnosed and managed in primary care practices; thus, primary care physicians have a significant opportunity to improve patient outcomes. Following publication of the 2006 European League Against Rheumatism (EULAR) gout guidelines, significant new evidence has accumulated, and new treatments for patients with gout have become available. It is the objective of these 2011 recommendations to update the 2006 EULAR guidelines, paying special attention to the needs of primary care physicians. The revised 2011 recommendations are based on the Grading of Recommendations Assessment, Development, and Evaluation approach as an evidence-based strategy for rating quality of evidence and grading the strength of recommendation formulated for use in clinical practice. A total of 26 key recommendations, 10 for diagnosis and 16 for management, of patients with gout were evaluated, resulting in important updates for patient care. The presence of monosodium urate crystals and/or tophus and response to colchicine have the highest clinical diagnostic value. The key aspect of effective management of an acute gout attack is initiation of treatment within hours of symptom onset. Low-dose colchicine is better tolerated and is as effective as a high dose. When urate-lowering therapy (ULT) is indicated, the xanthine oxidase inhibitors allopurinol and febuxostat are the options of choice. Febuxostat can be prescribed at unchanged doses for patients with mild-to-moderate renal or hepatic impairment. The target of ULT should be a serum uric acid level that is ≤ 6 mg/dL. For patients with refractory and tophaceous gout, intravenous pegloticase is a new treatment option. This article is a summary of the 2011 clinical guidelines published in Postgraduate Medicine. This article provides a streamlined, accessible overview intended for quick review by primary care physicians, with the full guidelines being a resource for those seeking additional background information and expanded discussion.