Brief Report: Monosodium Urate Monohydrate Crystal Deposits Are Common in Asymptomatic Sons of Patients With Gout: The Sons of Gout Study

Gout, Hyperuricemia and Psoriatic Arthritis: An Evolving Conundrum

PURPOSE OF REVIEW

The co-existence of gout and psoriatic disease (PD) is long standing but more recently frequently encountered in clinical settings due to increased awareness of their shared comorbidities and clinical phenotypes, often posing diagnostic and management challenges. Here we review the overlap in gout and PD focusing on shared clinical features, common inflammatory pathophysiology and comorbidities which may prompt a diagnosis of 'Psout' and lead to changes in management.

RECENT FINDINGS

Several epidemiological studies have highlighted the increased incidence of hyperuricemia and gout in those with PD and vice versa. Although the role of monosodium urate (MSU) crystals is well recognized in activation of innate immunity via inflammasome and NETosis, it is likely that they have a role in triggering adaptive immunity via antigen presenting cells and their autocrine effect on keratinocytes in psoriasis (PSO), ultimately leading to T cell secretion of proinflammatory cytokines such as IL17. Hyperuricemia (HU) is common in PD (up to 30%) and underpins metabolic syndrome comorbidities that are common to both gout and PD. Shared clinical phenotypes and co-morbidities are routinely observed in clinical practice yet there is a paucity of evidence evaluating the effect of treating hyperuricemia/gout on PD activity, with small scale clinical trials showing a positive effect. There were no studies to our knowledge assessing gout disease activity with concurrent treatment of PD. The association between gout and PD is likely due to shared multimorbidity and perhaps to a smaller extent, the direct role of HU in triggering the release of proinflammatory cytokines in PD. There is often a significant overlap in clinical and radiological presentation of gout and Psoriatic arthritis (PsA). In those with atypical response to standard treatments of the primary condition (either gout or PsA), it would be plausible to investigate and treat for the other 'secondary' condition. This is particularly relevant and relatively feasible in those with PsA (and features of HU and multimorbidity) who respond poorly to standard immunomodulating treatments.

Imaging comparative analysis of familial and sporadic gout in Chinese men by multijoint ultrasonography

Objective

This study aimed to compare the imaging features of bilateral knees, ankles, and the first metatarsophalangeal joint using high-frequency ultrasonography in male patients with familial and sporadic primary gout and sought to elucidate the relationship between the presence of tophi and various clinical indicators.

Method

Male patients with primary gouty arthritis (GA) in the acute phase presenting to the Department of Rheumatology and Immunology at the First Affiliated Hospital of Chengdu Medical College from November 2020 to June 2022 were enrolled and classified into familial and sporadic gout groups. Comparative analyses of their clinical data and ultrasonographic imaging findings of the knees, ankles, and first metatarsophalangeal joints were performed between the groups. Univariate and multivariate logistic regression analyses, as well as receiver operating characteristic (ROC) analysis, were conducted to determine the effectiveness of significant factors in the prediction of tophi.

Result

In comparison to male patients with sporadic gout, those with familial primary gout exhibited lower age, body mass index, disease duration, and serum uric acid (SUA) levels. However, they demonstrated higher incidences of tophi and bone erosion (54.6% in familial gout vs. 35.1% in sporadic gout, p < 0.05; 71.2% in familial gout vs. 48.1% in sporadic gout, p < 0.05, respectively), with a greater prevalence of tophi in the right first metatarsophalangeal joint (44.2% in familial gout vs. 32.3% in sporadic gout, p < 0.05). Independent risk factors for tophi included family history (OR = 6.712), age (OR = 1.049), disease duration (OR = 1.134), and SUA levels (OR = 1.006). ROC analysis yielded an area under the curve of 0.883 (p < 0.05) for predicting joint tophi using these factors.

Conclusion

Male patients with familial primary GA in the acute phase experienced earlier onset, shorter disease duration compared to those with sporadic gout. They also had more affected joints, more frequent and a wider distribution of tophi, especially in the right first metatarsophalangeal joint. Family history, age, disease duration, and SUA levels are predictive of tophi formation.

Development of gout in people with asymptomatic hyperuricemia: study protocol for a 5-year prospective cohort

INTRODUCTION

The central biochemical cause of gout is hyperuricemia (elevated serum urate levels). Ultrasound features of monosodium urate (MSU) crystal deposition are common in people with asymptomatic hyperuricemia. However, it is unclear whether this is a precondition for the development of gout. This study aims to determine whether ultrasound imaging evidence of MSU crystal deposition predicts development of symptomatic gout over 5 years, in people who already have an increased risk of gout due to elevated serum urate concentrations (≥8 mg/dL).

METHODS AND ANALYSIS

This is a prospective, international, multicentre study. The study population comprises over 250 participants with asymptomatic hyperuricemia (serum urate ≥8.0 mg/dL). After the baseline assessments, participants are followed for 5 years or until the development of gout, defined by the 2015 American College of Rheumatology/European Alliance of Associations for Rheumatology gout classification criteria. Baseline assessments include anthropomorphic measures, laboratory tests, questionnaires, blood and urine specimen collection, plain radiographs of the feet and standardised ultrasound scans of the lower limbs, scored according to the Outcomes in Rheumatology (OMERACT) gout ultrasound scoring system. The primary outcomes are the development of gout and time course for development of gout in people with and without ultrasound evidence of MSU crystal deposition. Exploratory analyses will examine clinical, genetic and biological factors associated with development of MSU crystal deposition and gout.

ETHICS AND DISSEMINATION

This study protocol was approved by the New Zealand Ministry of Health Southern Health and Disability Ethics Committee (MEC/05/10/130/AM16) on 18 December 2018. The findings from this study will be published in peer-reviewed journals and will be presented at national and international conferences.

TRIAL REGISTRATION NUMBER

ACTRN12619000915156.

Preclinical gout is common in the patient with stage 3-5 chronic kidney disease. Relevance of musculoskeletal ultrasound

BACKGROUND

One in 10 patients with hyperuricemia may develop gout over time, with urate deposition sometimes asymptomatic. Recent reviews and guidelines support ultrasound (US) to assess asymptomatic hyperuricemic (AH) patients to detect gout lesions, showing double contour (DC) and tophus the highest specificities and positive predictive values. Hyperuricemia and gout are common in chronic kidney disease (CKD), especially with glomerular filtration rate (GFR) <60, and both are associated with worse prognosis, although treatment of AH in CKD is not yet recommended in all guidelines. US gout lesions have been found more frequently in AH (up to 35%) than in normouricemic (NU) patients, but evidence is scarce in CKD.

OBJECTIVES

To assess the prevalence of urate deposit in stages 3-5 CKD detected by US, and to investigate if there are differences between AH and NU patients.

METHODS

Multicenter cross-sectional study, recruiting patients aged ≥18 years with AH and stages 3-5 CKD in 4 hospitals. A comparator group of NU patients with stage 3-5 CKD was included.

EXCLUSION CRITERIA

previous diagnosis of gout, tophi. Hyperuricemia was defined as serum uric acid (sUA) >7 mg/dl, documented at least twice during the last 12 months. A standardized US exam of the knees and bilateral first metatarsophalangeal joints was performed to assess patients for DC/tophus as defined by OMERACT. Demographic, clinical and laboratory data were recorded. A descriptive analysis was performed using SPSS. Pre-clinical gout (PCG: DC and/or tophus) was considered as outcome variable. Chi-square and Fisher's exact test were used for qualitative variables, and Mann-Whitney U test for quantitative variables; significant threshold p < 0.05.

RESULTS

Fifty-three patients with stages 3-5 CKD (59.6% stage 3, 19.1% stage 4, 21.3% stage 5) were recruited, 38 AH (71.7%) and 15 NU. A higher prevalence of US findings was observed in HU patients compared to NU patients (DC 23.7% vs 13.3%, tophus 31.6% vs 26.7%, PCG 39.5% vs 33.3%), although the differences were not statistically significant. NU patients had CKD of longer duration than HU patients [11 (7.2-13.5) vs 6 (2-9.2) years; p = 0.02], with no differences in sex, age, comorbidities, or urate-lowering therapy (ULT) (66.7% vs 44.7%; p = 0.05) and other treatments. Seventy percent of NU patients with TRU had AH before starting treatment. In patients with tophi, we observed a trend towards shorter duration of CKD and shorter duration of treatment with ULT compared to those without tophi [3.5 (2-6.7) vs 7 (3-12) years; p = 0.05] and [22 (12-44) vs 39 (29-73) months; p = 0.08], respectively. This trend was also observed in PCG, but not in DC, first US sign to disappear after initiation of ULT. Ninety percent of patients (100% in non-dialyzed patients) with PCG had a median uricemia ≥5 mg/dl in the past 12 months.

CONCLUSION

We found a significant prevalence of asymptomatic urate deposition in patients with stage 3-5 CKD, mostly in subjects with median uricemia ≥5 mg/dl in the last 12 months. Early diagnosis of PCG by musculoskeletal US in CKD may allow earlier introduction and optimization of ULT. This will probably contribute to slowing down the progression of this pathology, which makes it essential to promote collaboration between Nephrology and Rheumatology.

Early-onset gout

Early-onset gout (EOG) is characterized by the occurrence of the first symptoms of gout at an unusually young age, usually <40 years. The aim of this review is to provide an overview of the epidemiology, clinical presentation and prognosis, association with comorbidities and specific management of EOG. A particularly high proportion of patients with EOG come from ethnic groups with stronger genetic factors, such as populations in the Pacific and Taiwan, who therefore have the highest prevalence of gout overall. The clinical presentation and severity of gout are broadly similar between EOG and common gout, although a longer disease duration exacerbates the disease, which more often tends to become polyarticular. Patients suffering from EOG develop metabolic comorbidities commonly associated with gout earlier in life, although those tend to be less frequent at the time of diagnosis. Some international guidelines recommend early treatment of EOG patients with urate-lowering therapies.

Mild hyperthermia enhanced synergistic uric acid degradation and multiple ROS elimination for an effective acute gout therapy

BACKGROUND

Acute gouty is caused by the excessive accumulation of Monosodium Urate (MSU) crystals within various parts of the body, which leads to a deterioration of the local microenvironment. This degradation is marked by elevated levels of uric acid (UA), increased reactive oxygen species (ROS) production, hypoxic conditions, an upsurge in pro-inflammatory mediators, and mitochondrial dysfunction.

RESULTS

In this study, we developed a multifunctional nanoparticle of polydopamine-platinum (PDA@Pt) to combat acute gout by leveraging mild hyperthermia to synergistically enhance UA degradation and anti-inflammatory effect. Herein, PDA acts as a foundational template that facilitates the growth of a Pt shell on the surface of its nanospheres, leading to the formation of the PDA@Pt nanomedicine. Within this therapeutic agent, the Pt nanoparticle catalyzes the decomposition of UA and actively breaks down endogenous hydrogen peroxide (H2O2) to produce O2, which helps to alleviate hypoxic conditions. Concurrently, the PDA component possesses exceptional capacity for ROS scavenging. Most significantly, Both PDA and Pt shell exhibit absorption in the Near-Infrared-II (NIR-II) region, which not only endow PDA@Pt with superior photothermal conversion efficiency for effective photothermal therapy (PTT) but also substantially enhances the nanomedicine's capacity for UA degradation, O2 production and ROS scavenging enzymatic activities. This photothermally-enhanced approach effectively facilitates the repair of mitochondrial damage and downregulates the NF-κB signaling pathway to inhibit the expression of pro-inflammatory cytokines.

CONCLUSIONS

The multifunctional nanomedicine PDA@Pt exhibits exceptional efficacy in UA reduction and anti-inflammatory effects, presenting a promising potential therapeutic strategy for the management of acute gout.

Moving urate-lowering therapy in gout beyond guideline recommendations

The 'treat-to target serum urate strategy' when using urate-lowering therapy has been recommended by most specialist rheumatology societies for many years. An alternative "treat-to-avoid-symptoms" in gout has been suggested, albeit without a clear definition of what this means and how it might be implemented in clinical trials or clinical practice. This has hampered efforts to design clinical trials that compare the "treat-to-target [urate]" and "treat-to-avoid-symptoms" strategies in the long-term management of gout. In this review we consider the rationale for the treat-to-target urate strategy when using urate-lowering therapy, potential definitions of a "treat-to-avoid-symptoms" strategy, or perhaps what is not "treat-to-avoid-symptoms", and approaches that might address this uncertainty.

Alterations in lipidome profiles distinguish early-onset hyperuricemia, gout, and the effect of urate-lowering treatment

BACKGROUND

Currently, it is not possible to predict whether patients with hyperuricemia (HUA) will develop gout and how this progression may be affected by urate-lowering treatment (ULT). Our study aimed to evaluate differences in plasma lipidome between patients with asymptomatic HUA detected ≤ 40 years (HUA ≤ 40) and > 40 years, gout patients with disease onset ≤ 40 years (Gout ≤ 40) and > 40 years, and normouricemic healthy controls (HC).

METHODS

Plasma samples were collected from 94 asymptomatic HUA (77% HUA ≤ 40) subjects, 196 gout patients (59% Gout ≤ 40), and 53 HC. A comprehensive targeted lipidomic analysis was performed to semi-quantify 608 lipids in plasma. Univariate and multivariate statistics and advanced visualizations were applied.

RESULTS

Both HUA and gout patients showed alterations in lipid profiles with the most significant upregulation of phosphatidylethanolamines and downregulation of lysophosphatidylcholine plasmalogens/plasmanyls. More profound changes were observed in HUA ≤ 40 and Gout ≤ 40 without ULT. Multivariate statistics differentiated HUA ≤ 40 and Gout ≤ 40 groups from HC with an overall accuracy of > 95%.

CONCLUSION

Alterations in the lipidome of HUA and Gout patients show a significant impact on lipid metabolism. The most significant glycerophospholipid dysregulation was found in HUA ≤ 40 and Gout ≤ 40 patients, together with a correction of this imbalance with ULT.

Upregulated expression of FFAR2 and SOC3 genes is associated with gout

OBJECTIVE

To examine the expression of Free fatty acid receptor 2 (FFAR2) and Suppressor of cytokine signalling 3 (SOCS3) genes in asymptomatic hyperuricaemia (AH), AH with MSU crystal deposition, inter-critical gout and gout flare.

METHODS

Study participants (n = 120) comprised 34 people with serum urate (SU) <360 μmol/l, 69 with AH ± MSU crystal deposition and 17 with a gout flare. Sixteen of the 17 patients with a gout flare attended a second visit 6-12 weeks later. Gene expression levels were assessed using RT-qPCR and results computed as fold changes (FC) after normalization to the reference gene.

RESULTS

FFAR2 was significantly upregulated during gout flares (FC = 2.9) compared with normal SU, AH, and AH + MSU crystal deposition (FC = 1.1, P < 0.0001 for each comparison). FFAR2 was also significantly upregulated during inter-critical gout (FC = 1.8) compared with normal SU, AH and AH + MSU (FC = 1.1, P < 0.001 for each comparison). SOCS3 was significantly upregulated during gout flares (FC = 3.4) compared with normal SU, AH, and AH + MSU crystal deposition (FC = 1.1, 1.1 and 1.2, respectively, P < 0.0001 for each comparison). SOCS3 was also upregulated during inter-critical gout (FC = 2.1) compared with normal SU (P = 0.02) and AH (P = 0.006) (FC = 1.1 and 1.2, respectively). FFAR2 expression was upregulated during gout flare compared with inter-critical gout and SOCS3 expression showed negative correlation with flare duration (r = -0.49, P < 0.05).

CONCLUSION

FFAR2 upregulation is associated with gout and may trigger gout flares. SOCS3 may have a role in amelioration of gout flares.

Update of the current role of ultrasound in asymptomatic hyperuricemia. A systematic literature review

Ultrasound (US) is a recognized imaging modality for the assessment of gout. Recently it is being explored for its potential role in the evaluation of subjects with asymptomatic hyperuricemia (AH). Preliminary reports demonstrated the presence of monosodium urate (MSU)-crystal deposits including aggregates, double contour sign and/or tophi in both intra-articular and periarticular tissues of AH individuals. Although these results are exciting, the value and potential application of US in AH remain to be clearly delineated. In this systematic literature review, we aim to summarise the recent publications regarding the role of US in the assessment of AH. We analyzed possible application of US in the daily clinical practice and its future clinical and research potential in the evaluation of AH individuals.

Global research trends in hyperuricemia: A bibliometric and visualised study

OBJECTIVES

The global trend of research on hyperuricaemia (HUA) has not been well studied. Therefore, this study aimed to investigate the trend of research on HUA and compare the findings in publications from different countries, institutions, journals, and authors, to predict the research hotspots.

METHODS

Publications related to HUA were searched using the Science Citation Index-Expanded Web of Science. The data were analysed by using the bibliometric methodology. Additionally, a graphical mapping was generated by using the VOS viewer software to carry out a co-occurrence analysis and to investigate the trend of publications in this field.

RESULTS

A total of 6313 articles were included. The number of publications was increasing globally yearly. USA was the leading country in global research in this field, with the largest number of publications and citations as well as the highest H-index (H-index reflects both the number of publications and the number of citations per publication). PLOS One published the largest number of publications related to HUA. JOHNSON RJ T has published the largest number of papers in this field. Published studies could be classified into six clusters: 'Pathophysiology', 'HUA and metabolic syndrome', 'HUA and cardiovascular disease', 'HUA and gout', 'HUA and nephropathy', and 'Genome-wide research'. 'Pathophysiology', 'HUA and cardiovascular disease', 'HUA and gout', and 'Genome-wide research' were predicted as the next hot topics in HUA research.

CONCLUSIONS

USA was the leading country in global research in this field. It is expected that an increasing research output will continue to be observed in the near future. 'Pathophysiology', 'HUA and cardiovascular disease', 'HUA and gout', and 'Genome-wide research' may be the next hotspots and hence need more attention in the future.

Contentious Issues in Gout Management: The Story so Far

Gout is the most common inflammatory arthritis worldwide. Although gout has been known for antiquity, many challenges still exist in gout management. It is vital to view gout as a chronic disease and not just treat the acute flare. There is a perception of gout as an acute disease requiring treatment only for acute flares. However, to combat the disease, chronic urate-lowering therapy, reducing the serum urate levels to below the saturation threshold of 6.8 mg/dL, and chronic anti-inflammatory prophylaxis, especially during urate-lowering therapy initiation, are needed. In this manuscript, we discuss some of the contentious issues in gout management. These include the timing of urate-lowering therapy initiation, which urate-lowering therapy to chose, should comorbidities influence our treatment, using genetic determinants, and patient perspectives to drive treatment and differences between gout treatment the American College of Physicians and Rheumatology guidelines for gout management: driving care.

NEUTROPHIL EXTRACELLULAR TRAPS RELEASE IN GOUT AND PSEUDOGOUT DEPENDS ON THE NUMBER OF CRYSTALS REGARDLESS OF LEUKOCYTE COUNT

OBJECTIVES

Microcrystal-induced arthritis is still an unresolved paradigm for medicine. Overt inflammation may be absent even when crystals occur in synovial fluid. Recently, the production of neutrophil extracellular traps (NETs) embedding monosodium urate crystals (MSU) has been proposed as a possible mechanism of the auto-resolution of the inflammatory phase during gout. We aimed to verify and quantify the release of NETs in synovial fluids during gout and pseudogout attacks and to compare any differences with respect to crystals and neutrophils number, and to analyze activation of necroptosis pathway in synovial fluid from crystal-induced arthritis.

METHODS

Synovial fluid samples were obtained by arthrocentesis from 22 patients presenting acute crystal-induced arthritis, gout or pseudogout (n = 11 each group), and from 10 patients with acute non-crystal arthritis as controls. NETosis was quantified in synovial fluid by nucleic acid stain and by quantification of human neutrophil elastase. Activation of p-MLKL was assessed by western blot.

RESULTS

We observed that synovial fluid neutrophils encountering MSU and CPPD crystals during episodes of gout and pseudogout release NETs in relation to the number of crystals in synovial fluid and irrespective of neutrophil density and type of crystal. This release was accompanied by necroptosis through the activation of the MLKL pathway.

CONCLUSIONS

Our findings suggest that a role of NETs in crystal-induced arthritis is to "trap extracellular particles", including microcrystals. Embedding crystals in aggregates of NETs may be the basis of tophi and CPPD deposition and may have implications for disease evolution, rather than for spontaneous resolution of the acute attack.

Matrix Metalloproteinase-3 induces proteoglycan degradation in gouty arthritis model

BACKGROUND

Gout is an inflammatory arthritis resulting from precipitation of monosodium urate (MSU) crystals in joints and surrounding tissues. However, the mechanism underlying high levels of uric acid inducing gouty arthritis has not been clarified.

OBJECTIVE

The purpose was to investigate the role of Matrix Metalloproteinase-3 (MMP-3) in the development of gouty arthritis from hyperuricemia.

METHOD

MSU crystal-induced gouty arthritis model and chondrocytes were used to evaluate changes of MMP-3 levels. Western blot, qPCR and ELISA were performed to detect MMP-3, Tissue Inhibitors of Metalloproteinase-1 (TIMP-1) and A Disintegrin and Metalloproteinase with Thrombospondin Motifs-4 (ADAMTS-4) expressions in rabbit chondrocytes. Expression of proteoglycan was determined through toluidine blue staining. Concentrations of glycosaminoglycan, Interleukin-6 (IL-6), Interleukin-1β (IL-1β) and Tumor Necrosis Factor-α (TNF-α) in chondrocytes were assessed via ELISA kits. Concentration of uric acid in supernate was tested by Automatic Analyzer.

RESULTS

MMP-3 was significantly increased in rat serum, synovial fluid, cartilages and chondrocytes treated with high-level uric acid. Increased concentration of glycosaminoglycancould be observed in chondrocytes incubated with MMP-3, as well as the remarkable downregulation of proteoglycan expression. Furthermore, high-level uric acid contributed to the degradation of proteoglycan via the activation of MMP-3. IL-6, IL-1β and TNF-α concentrations were increased significantly in 35 °C compared to 37 °C with MMP-3 and high-level uric acid.

CONCLUSION

Our study showed that MMP-3 was enhanced by high levels of uric acid, which promoted proteoglycan degradation, and induced MSU crystallization in turn. A low temperature environment is an important factor in the development of gout.

Gout

Gout is a chronic disease caused by monosodium urate (MSU) crystal deposition. Gout typically presents as an acute, self-limiting inflammatory monoarthritis that affects the joints of the lower limb. Elevated serum urate level (hyperuricaemia) is the major risk factor for MSU crystal deposition and development of gout. Although traditionally considered a disorder of purine metabolism, altered urate transport, both in the gut and the kidneys, has a key role in the pathogenesis of hyperuricaemia. Anti-inflammatory agents, such corticosteroids, NSAIDs and colchicine, are widely used for the treatment of gout flare; recognition of the importance of NLRP3 inflammasome activation and bioactive IL-1β release in initiation of the gout flare has led to the development of anti-IL-1β biological therapy for gout flares. Sustained reduction in serum urate levels using urate-lowering therapy is vital in the long-term management of gout, which aims to dissolve MSU crystals, suppress gout flares and resolve tophi. Allopurinol is the first-line urate-lowering therapy and should be started at a low dose, with gradual dose escalation. Low-dose anti-inflammatory therapies can reduce gout flares during initiation of urate-lowering therapy. Models of care, such as nurse-led strategies that focus on patient engagement and education, substantially improve clinical outcomes and now represent best practice for gout management.

The impact of dysfunctional variants of ABCG2 on hyperuricemia and gout in pediatric-onset patients

BACKGROUND

ABCG2 is a high-capacity urate transporter that plays a crucial role in renal urate overload and extra-renal urate underexcretion. Previous studies have suggested an association between hyperuricemia and gout susceptibility relative to dysfunctional ABCG2 variants, with rs2231142 (Q141K) being the most common. In this study, we analyzed the ABCG2 gene in a hyperuricemia and gout cohort focusing on patients with pediatric-onset, i.e., before 18 years of age.

METHOD

The cohort was recruited from the Czech Republic (n = 234) and consisted of 58 primary hyperuricemia and 176 gout patients, with a focus on pediatric-onset patients (n = 31, 17 hyperuricemia/14 gouts); 115 normouricemic controls were used for comparison. We amplified, sequenced, and analyzed 15 ABCG2 exons. The chi-square goodness-of-fit test was used to compare minor allele frequencies (MAF), and the log-rank test was used to compare empirical distribution functions.

RESULTS

In the pediatric-onset cohort, two common (p.V12M, p.Q141K) and three very rare (p.K360del, p.T421A, p.T434M) allelic ABCG2 variants were detected. The MAF of p.Q141K was 38.7% compared to adult-onset MAF 21.2% (OR = 2.4, P = 0.005), to the normouricemic controls cohort MAF 8.5% (OR = 6.8, P <  0.0001), and to the European population MAF 9.4% (OR = 5.7, P <  0.0001). The MAF was greatly elevated not only among pediatric-onset gout patients (42.9%) but also among patients with hyperuricemia (35.3%). Most (74%) of the pediatric-onset patients had affected family members (61% were first-degree relatives).

CONCLUSION

Our results show that genetic factors affecting ABCG2 function should be routinely considered in a hyperuricemia/gout diagnosis, especially in pediatric-onset patients. Genotyping of ABCG2 is essential for risk estimation of gout/hyperuricemia in patients with very early-onset and/or a family history.

Prevalence and discrimination of OMERACT-defined elementary ultrasound lesions of gout in people with asymptomatic hyperuricaemia: A systematic review and meta-analysis

OBJECTIVES

Ultrasound lesions of gout have been described in people with asymptomatic hyperuricemia. However, the anatomical sites and ultrasound lesions most frequently involved in asymptomatic hyperuricemia have not yet been established. This systematic review and meta-analysis aimed to determine the prevalence of the Outcome Measures in Rheumatology (OMERACT) elementary ultrasound lesions of gout (double contour, aggregates, tophus, erosion) at various sites in people with asymptomatic hyperuricemia and to determine which sites and lesions discriminate from people with normouricemia.

METHODS

A systematic search of electronic databases, conference abstracts and reference lists was undertaken. Studies were included if they used ultrasound to image people with asymptomatic hyperuricemia and reported ≥1 OMERACT-defined lesion of gout. Meta-analyses were undertaken for the pooled prevalence of site-specific lesions in people with asymptomatic hyperuricemia, and the pooled odds ratios of these lesions compared to people with normouricemia.

RESULTS

Twenty studies were included. The most common site scanned was the first metatarsophalangeal joint (1MTP) (n = 17 studies) and the most common lesion reported, the double contour (n = 18). Meta-analyses of pooled prevalence showed 1MTP double contour was the most frequent finding in people with asymptomatic hyperuricemia (0.31, 95% confidence interval (CI) 0.20-0.42), followed by femoral condyle double contour (0.16, 95%CI 0.08-0.24) and 1MTP tophus (0.16, 95%CI 0.03-0.29). The highest pooled odds ratios for asymptomatic hyperuricemia vs. normouricemia were 6.98 (95%CI 3.14-15.57) for 1MTP double contour, 13.67 (95%CI 5.42-34.49) for femoral condyle double contour and 6.10 (95%CI 1.55-24.04) for 1MTP tophus.

CONCLUSION

In people with asymptomatic hyperuricemia, scanning of the 1MTP and femoral condyle for double contour, plus the 1MTP for tophus, has the highest prevalence and discrimination compared to those with normouricemia.

How should we manage asymptomatic hyperuricemia?

The definition of asymptomatic hyperuricemia remains unclear, as no consensus exists about the serum urate cutoff or the relevance of ultrasound findings. Comorbidities associated with hyperuricemia have increased in frequency over the past two decades. Hyperuricemia (and/or gout) may be a cause or a consequence of a comorbidity. Whereas epidemiological studies suggest that hyperuricemia may be linked to cardiovascular, metabolic, and renal comorbidities, Mendelian randomization studies have not provided proof that these links are causal. Discrepancies between findings from observational studies and clinical trials preclude the development of recommendations about the potential benefits of urate-lowering therapy (ULT) in individual patients with asymptomatic hyperuricemia. The risk/benefit ratio of ULT is unclear. The risk of developing gout, estimated at 50%, must be weighed against the risk of cutaneous and cardiovascular side effects of xanthine oxidase inhibitors. The need for optimal comorbidity management, in contrast, is universally accepted. Medications for comorbidities that elevate urate levels should be discontinued and replaced with medications that have the opposite effect. Therapeutic lifestyle changes, weight loss as appropriate, and sufficient physical activity are useful for improving general health. Whether ULT has beneficial effects on comorbidities will be known only when well-powered interventional trials with relevant primary endpoints are available.