Serum Urate Research Articles

Modifiable risk factors and incident cardiovascular events in gout patients

Abstract Background Gout is associated with increased risks of cardiovascular events. However, it remains uncertain whether achieving the control targets for risk factors can attenuate this risk. This study evaluated the association between the attainment of targeted seven risk factors and the incidence of major adverse cardiovascular events (MACCE) among patients with gout. Methods From the UK Biobank database, we analyzed data from participants diagnosed with gout at baseline (2006-2010). These individuals were followed to monitor the incidence of MACCE. Gout patients were stratified based on the achievement of seven predefined risk factor targets at baseline: body mass index 18.5-24.9, adherence to a high-quality diet, engagement in regular exercise, non-smoking status, abstention from alcohol, hemoglobin A1c <48 mmol/mol, and serum urate < 360 μmol/L. The primary outcome was the incidence of MACCE, encompassing all-cause death, stroke, or myocardial infarction. Cox model was used to identify independent predictors of MACCE. Results After a median follow-up of 14.1 years, 1,318 of 6,273 gout patients developed MACCE. Among individuals with gout, the risk of MACCE decreased stepwise with the number of optimally managed modifiable risk factors. For participants exhibiting 1, 2, 3, and ≥4 optimal modifiable factors, the hazard ratios (HRs) were 0.39 (95% confidence interval (CI): 0.26-0.58), 0.30 (95%CI: 0.20-0.44), 0.28 (95%CI: 0.19-0.41), and 0.24 (95%CI: 0.16-0.36) respectively, showing a significant trend towards risk reduction (Ptrend <0.001). Conclusion Among individuals with gout, there is a stepwise decrease in the risk of MACCE with every additional risk factor that is optimally controlled.Study flowStratified analysis for adjusted HRs

NUMB dysfunction defines a novel mechanism underlying hyperuricemia and gout

Defective renal excretion and increased production of uric acid engender hyperuricemia that predisposes to gout. However, molecular mechanisms underlying defective uric acid excretion remain largely unknown. Here, we report a rare genetic variant of gout-unprecedented NUMB gene within a hereditary human gout family, which was identified by an unbiased genome-wide sequencing approach. This dysfunctional missense variant within the conserved region of the NUMB gene (NUMBR630H) underwent intracellular redistribution and degradation through an autophagy-dependent mechanism. Mechanistically, we identified the uric acid transporter, ATP Binding Cassette Subfamily G Member 2 (ABCG2), as a novel NUMB-binding protein through its intracellular YxNxxF motif. In polarized renal tubular epithelial cells (RTECs), NUMB promoted ABCG2 trafficking towards the apical plasma membrane. Genetic loss-of-function of NUMB resulted in redistribution of ABCG2 in the basolateral domain and ultimately defective excretion of uric acid. To recapitulate the clinical situation in human gout patients, we generated a NUMBR630H knock-in mouse strain, which showed marked increases of serum urate and decreased uric acid excretion. The NUMBR630H knock-in mice exhibited clinically relevant hyperuricemia. In summary, we have uncovered a novel NUMB-mediated mechanism of uric acid excretion and a functional missense variant of NUMB in humans, which causes hyperuricemia and gout.

Effective xanthine oxidase inhibitor urate lowering therapy in gout is linked to an emergent serum protein interactome of complement and inflammation modulators

Urate-lowering treatment (ULT) to target with xanthine oxidase inhibitors (XOIs) paradoxically causes early increase in gouty arthritis flares. Because delayed reduction in flare burden is mechanistically unclear, we tested for ULT inflammation responsiveness markers. Unbiased proteomics analyzed blood samples (baseline, 48 weeks ULT) in two, independent ULT out trial cohorts (n = 19, n = 30). STRING-db and multivariate analyses supplemented determinations of altered proteins via Wilcoxon matched pairs signed rank testing in XOI ULT responders. Mechanistic studies characterized proteomes of cultured XOI-treated murine bone marrow macrophages (BMDMs). At 48 weeks ULT, serum urate normalized in all gout patients, and flares declined in association with significantly altered proteins (p < 0.05) in clustering and proteome networks in sera and peripheral blood mononuclear cells. Sera demonstrated altered complement activation and regulatory gene ontology biologic processes. In both cohorts, a treatment-emergent serum interactome included key gouty inflammation mediators (C5, IL-1B, CXCL8, IL6). Last, febuxostat treatment decreased complement activation biologic process proteins in cultured BMDMs. Reduced gout flares are linked with a XOI treatment-emergent serum protein interactome that includes inflammation regulators, associated with altered complement activation and regulatory biologic processes. Serum and leukocyte proteomics could help identify when gouty inflammatory processes begin to subside in response to ULT.Trial Registration: ClinicalTrials.gov Identifier NCT02579096, posted October 19, 2015.

Prediagnostic Amino Acid Metabolites and Risk of Gout, Accounting for Serum Urate: Prospective Cohort Study and Mendelian Randomization.

Our objective was to prospectively investigate prediagnostic population-based metabolome for risk of hospitalized gout (ie, most accurate, severe, and costly cases), accounting for serum urate. We conducted prediagnostic metabolome-wide analyses among 249,677 UK Biobank participants with nuclear magnetic resonance metabolomic profiling (N = 168 metabolites, including eight amino acids) from baseline blood samples (2006-2010) without a history of gout. We calculated multivariable hazard ratios (HRs) for hospitalized incident gout, before and after adjusting for serum urate levels; we included patients with nonhospitalized incident gout in a sensitivity analysis. Potential causal effects were evaluated with two-sample Mendelian randomization. Correcting for multiple testing, 107 metabolites were associated with incidence of hospitalized gout (n = 2,735) before urate adjustment, including glycine and glutamine (glutamine HR 0.64, 95% confidence interval [CI] 0.54-0.75, P = 8.3 × 10-8; glycine HR 0.69, 95% CI 0.61-0.78, P = 3.3 × 10-9 between extreme quintiles), and glycoprotein acetyls (HR 2.48, 95% CI 2.15-2.87, P = 1.96 × 10-34). Associations remained significant and directionally consistent following urate adjustment (HR 0.83, 95% CI 0.70-0.98; HR 0.86, 95% CI 0.76-0.98; HR 1.41, 95% CI 1.21-1.63 between extreme quintiles), respectively; corresponding HRs per SD were 0.91 (95% CI 0.86-0.97), 0.94 (95% CI 0.91-0.98), and 1.10 (95% CI 1.06-1.14). Findings persisted when including patients with nonhospitalized incident gout. Mendelian randomization corroborated their potential causal role on hyperuricemia or gout risk; with change in urate levels of -0.05 mg/dL (95% CI -0.08 to -0.01) and -0.12 mg/dL (95% CI -0.22 to -0.03) per SD of glycine and glutamine, respectively, and odds ratios of 0.94 (95% CI 0.88-1.00) and 0.81 (95% CI 0.67-0.97) for gout. These prospective findings with causal implications could lead to biomarker-based risk prediction and potential supplementation-based interventions with glycine or glutamine.

Weight Reduction and Target Serum Urate Level: A Longitudinal Study of Annual Medical Examination.

To evaluate associations of weight reduction with serum urate (SU) changes and achieving an SU <6 mg/dl in the real-world setting, outside of specific weight reduction interventions. We analyzed systematically collected data of annual medical examination participants from October 2012 to October 2022. Exposure was weight change (increase or decrease) between two consecutive visits, categorized as minimal (≤0.9 kg, reference), small (1.0-4.9 kg), moderate (5.0-9.9 kg), and large (≥10 kg). Outcomes included SU changes between two consecutive visits and achieving SU <6 mg/dL in hyperuricemic participants (SU ≥7 mg/dL at the prior visit). We identified 58,630 eligible participants (median age 46 years, female 51.3%, overweight 19.4%, median SU 5.3 mg/dL, history of gout and/or hyperuricemia 5.6%) with 336,814 visits over a median of 5.3 years. After adjusting for relevant covariates, linear general estimating equations estimated mean SU changes (95%CI) based on observed weight reductions (vs. minimal changes): small -0.10 (-0.10, -0.09) mg/dL, moderate -0.34 (-0.36, -0.32) mg/dL, and large -0.64 (-0.70, -0.58) mg/dL. In hyperuricemic participants, adjusted relative risks (95%CI) for achieving SU level <6 mg/dL by modified Poisson regression were 1.25 (1.15, 1.37) in small, 2.82 (2.43, 3.27) in moderate, and 5.27 (4.15, 6.70) in large weight reductions, with corresponding NNT of 61.1 for small weight reductions, 8.5 for moderate, and 3.6 for large. Small weight reductions were associated with only small SU changes. Some hyperuricemic participants can achieve the target SU level with moderate to large weight reductions.

Eleven Years of Change: Disease Progression in Biomarker-Defined Sporadic Parkinson's Disease.

Long-term longitudinal data on outcomes in sporadic Parkinson's Disease are limited, especially from cohorts with extensive biological characterization. Recent advances in biomarkers characterization of Parkinson's Disease necessitate an updated examination of long-term progression within contemporary cohorts like the Parkinson's Progression Markers Initiative, which enrolled individuals within 2 years of clinical diagnosis of Parkinson's Disease. Our study leverages the Neuronal Synuclein Disease framework, which defines the disease based on biomarker assessed presence of neuronal alpha-synuclein and dopamine deficit, rather than based on conventional clinical diagnostic criteria. In this study we aimed to provide a comprehensive long-term description of disease progression using the integrated biological and clinical staging system framework. We analyzed data from 344 participants from the sporadic Parkinson's Disease cohort in the Parkinson's Progression Markers Initiative, who met Neuronal Synuclein Disease criteria. We assessed 11-year progression in a spectrum of clinical measures. We used Cox proportional hazards models to assess the association between baseline stage and time to key outcomes, including survival, postural instability (Hoehn & Yahr ≥ 3), loss of independence (Schwab & England < 80%), cognitive decline, and domain-based milestones such as walking and balance, motor complications, autonomic dysfunction, and activities of daily living. Additional analyses were completed to account for death and participant dropout. Biomarker analysis included dopamine transporter binding measures, as well as serum urate, neurofilament light chain and CSF amyloid-beta, phosphorylated tau and total tau. At baseline, despite the cohort consisting of individuals within 2 years of clinical diagnosis, there was clear separation of participants in Neuronal Synuclein Disease Stages (23% Stage 2b, 67% Stage 3, 10% Stage 4). At 11 years, data were available for 153 participants; 35 participants had died over the follow up period. Of retained participants, 59% presented normal cognition, 24% had evidence of postural instability and mean Schwab & England score was 78.5. Serum neurofilament light chain consistently increased over time. No other biofluids had a consistent change in trajectory. Of importance, baseline Neuronal Synuclein Disease Stage predicted progression to clinically meaningful milestones. This study provides data on longitudinal, 11-year progression in Neuronal Synuclein Disease participants within 2 years of clinical diagnosis. We observed better long-term outcomes in this contemporary observational study cohort. It highlights the heterogeneity in the early Parkinson's Disease population as defined by clinical diagnostic criteria and underscores the importance of shifting from clinical to biologically and functionally based inclusion criteria in the design of new clinical trials.

6741 Serum Urate-Lowering Effects Of Sodium-Glucose Transport Protein 2 Inhibitors Compared To Dipeptidyl Peptidase-4 Inhibitors In Gout Patients With Type 2 Diabetes Mellitus: A Population-Based Cohort Study

Abstract Disclosure: R.K. Shariff: None. C. Chung: None. P. Huang: None. S. Mon: None. K. Ma: None. Background/Purpose: Effective management of gout in patients requiring long-term urate-lowering therapy involves maintaining serum rate levels within specific ranges. Hyperuricemia and gout have been associated with an increased risk of Type 2 Diabetes Mellitus (T2DM), with a reported prevalence of 16% in gout patients. Pharmacological approaches to glycemic control, including Sodium-glucose Transport Protein 2 Inhibitors inhibitor (SGLT2i) and Dipeptidyl Peptidase-4 Inhibitors (DPP-4i), have showed potential serum urate lowering effects. However, a direct comparison of these effects in patients with gout and concomitant T2DM is lacking. This study aims to evaluate the serum urate-lowering effects of SGLT2i compared to DPP-4i in this patient population. Methods: This was a population-based cohort study of patients with gout diagnosed following the 2015 Gout classification criteria in the American College of Rheumatology/European League Against Rheumatism collaborative initiative and T2DM diagnosed following the American Diabetes Association criteria, respectively. Subjects treated between 2008 and 2023 at 92 United States hospitals were screened. Propensity score matching was used to balance the baseline differences in age of gout onset, sex, comorbidities, and past medical history between the two groups. The primary predictor variable was the use of therapies of SGLT2i and DPP-4i. The primary outcome of interest was the serum urate more than 6 mg/dL during the follow-up period. Kaplan-Meier analysis and log-rank tests were utilized to compare if the numbers of serum urate were higher than 6 mg/dL in both arms. A Cox proportional hazards model was utilized to estimate the association between the use of SGLT2i versus DPP-4i and the numbers of serum urate higher than 6 mg/dL. Inclusion criteria include patients with gout and concomitant T2DM, age over 18, and must have serum uric acid level data available. Results: Of the 11,495 gout patients, including 3,593 users of SGLT2i users, were propensity score-matched to 3593 DPP-4i users. Among gout patients with T2DM on SGLT2i, 598 experienced serum urate levels exceeding than 6 mg/dL, while in the DPP-4i group, 920 patients had serum urate higher than 6 mg/dL. The use of SGLT2i was associated with significantly lower odds of serum uric acid exceeding 6 mg/dl compared to DPP-4i. (OR: 0.580 [0.517-0.651]). Conclusion: Our study suggests that SGLT2i may offer a more effective means of managing serum uric acid levels in gout patients with concomitant T2DM compared to DPP-4i. Clinical trials are required to validate the findings. For clinical practice, the dosage for SGLT2i to cause the urate-lowering effect needs to be investigated. With further studies and clinical trials, the rationale of choosing SGLT2i over DPP-4i may be incorporated into the management of T2DM in gout patients with T2DM. Presentation: 6/1/2024

Downregulation of type I interferon signalling pathway by urate in primary human PBMCs.

Type I interferons (IFN1s) mediate innate responses to microbial stimuli and regulate interleukin (IL)-1 and IL-1 receptor antagonist (Ra) production in human cells. This study explores interferon-stimulated gene (ISG) alterations in the transcriptome of patients with gout and stimulated human primary cells in vitro in relation to serum urate concentrations. Peripheral blood mononuclear cells (PBMCs) and monocytes of patients with gout were primed in vitro with soluble urate, followed by lipopolysaccharide (LPS) stimulation. Separately, PBMCs were stimulated with various toll-like receptor (TLR) ligands. RNA sequencing and IL-1Ra cytokine measurement were performed. STAT1 phosphorylation was assessed in urate-treated monocytes. Cytokine responses to IFN-β were evaluated in PBMCs cultured with or without urate and restimulated with LPS and monosodium urate (MSU) crystals. Transcriptomics revealed suppressed IFN-related signalling pathways in urate-exposed PBMCs or monocytes which was supported by diminishment of phosphorylated STAT1. The stimulation of PBMCs with IFN-β did not modify the urate-induced inflammation. Interestingly, in vivo, serum urate concentrations were inversely correlated to in vitro ISG expression upon stimulations with TLR ligands. These findings support a deficient IFN1 signalling in the presence of elevated serum urate concentrations, which could translate to increased susceptibility to infections.

Identifying the association between serum urate levels and gout flares in patients taking urate-lowering therapy: a post hoc cohort analysis of the CARES trial with consideration of dropout

ObjectiveTo investigate gout flare rates based on repeated serum urate (SU) measurements in a randomised controlled trial of urate-lowering therapy (ULT), accounting for dropout and death.MethodsWe performed a secondary analysis...

Gout risk in adults with pre-diabetes initiating metformin

ObjectiveDespite the strong association between gout and pre-diabetes, the role of metformin in gout among individuals with pre-diabetes remains uncertain. We compared the incidence rates of gout in adults with...

Systemic Inflammation In Asymptomatic Hyperuricemia With Sonographic Crystal Deposits, Including A Comparison With Normouricemia And Gout.

To describe the inflammatory profile of asymptomatic hyperuricemia (AH) with ultrasound evidence of monosodium urate (MSU) crystals (AH-MSUpos), vs AH without deposits (AH-MSUneg), intercritical gout, and normouricemia. Based on serum urate levels, musculoskeletal ultrasound, and history of flares, we divided 122 participants into four groups: normouricemia, AH-MSUneg, AH-MSUpos, and intercritical gout. We tested four ultrasound definitions for MSU deposition in AH: grade 2-3 (G2-3) double contour and/or tophi, G1-3 double contour and/or tophi, G1-3 Stewart scheme (double contour sign in knee cartilage and/or first metatarsophalangeal joint and/or tophi in first metatarsophalangeal joint), and G2-3 Stewart scheme. Serum acute phase reactants, cytokines, pyroptosis derivates, and neutrophil-related proteins were measured and compared between groups. A linear regression model was fitted to correlate crystal and inflammatory burden (measured by ultrasound) with inflammatory markers in hyperuricemics. Rates of MSU deposition in AH ranged from 26.0% to 68.8%, depending on the definition used. Levels of CRP, leukocytes, IL-1RA, IL-6, sIL-6R, IL-18, TNF-α, TGF-β, and galectin-3 were higher in hyperuricemics vs normouricemics. Sex, obesity, and comorbidity scores influenced some comparisons. We saw no differences comparing AH-MSUpos vs AH-MSUneg groups, except for higher calprotectin using G1-3 sonographic definitions and higher CRP and TGF-β when restricted to women and obese participants. Hyperuricemia is associated with substantial inflammation and some degree of active pyroptosis. Four different ultrasound definitions for AH with MSU deposits yielded similar findings, although we noted some differences in calprotectin, CRP, and TGF-β. Sex, obesity, and comorbidities influenced some inflammatory responses.

Whole-genome sequencing reveals rare variants associated with gout in Taiwanese males.

To identify rare variants (RVs) of gout, we sequenced the whole genomes of 321 male gout patients and combined these with those of 64 male gout patients and 682 normal controls at Taiwan Biobank. We performed ACAT-O to identify 682 significant RVs (p < 3.8 × 10-8) clustered on chromosomes 1, 7, 10, 16, and 18. To prioritize causal variants effectively, we sifted them by Combined Annotation-Dependent Depletion score >10 or |effect size| ≥ 1.5 for those without CADD scores. In particular, to the best of our knowledge, we identified the rare variants rs559954634, rs186763678, and 13-85340782-G-A for the first time to be associated with gout in Taiwanese males. Importantly, the RV rs559954634 positively affects gout, and its neighboring gene NPHS2 is involved in serum urate and expressed in kidney tissues. The kidneys play a major role in regulating uric acid levels. This suggests that rs559954634 may be involved in gout. Furthermore, rs186763678 is in the intron of NFIA that interacts with SLC2A9, which has the most significant effect on serum urate. Note that gene-gene interaction NFIA-SLC2A9 is significantly associated with serum urate in the Italian MICROS population and a Croatian population. Moreover, 13-85340782-G-A significantly affects gout susceptibility (odds ratio 6.0; P = 0.038). The >1% carrier frequencies of these potentially pathogenic (protective) RVs in cases (controls) suggest the revealed associations may be true; these RVs deserve further studies for the mechanism. Finally, multivariate logistic regression analysis shows that the rare variants rs559954634 and 13-85340782-G-A jointly are significantly associated with gout susceptibility.

The Causal Effect of Urate Level on Female Infertility: A Mendelian Randomization Study.

This study aimed to investigate the causal relationship between urate level and female infertility using Mendelian randomization (MR) analysis. To identify instrumental variables, we selected independent genetic loci associated with serum urate levels in individuals of European ancestry, utilizing data from large-scale genome-wide association studies (GWAS). The GWAS dataset included information on serum urate levels from 288,649 CKDGen participants. Female infertility data, including different etiologic classifications, consisted of 13,142 female infertility patients and 107,564 controls. We employed four MR methods, namely inverse variance weighted (IVW), MR-Egger, weighted median, and weighted model, to investigate the causal relationship between urate levels and female infertility. The Cochran Q-test was used to assess heterogeneity among single nucleotide polymorphisms (SNPs), and the MR-Egger intercept test was employed to evaluate the presence of horizontal pleiotropy. Additionally, a "leave-one-out" sensitivity analysis was conducted to examine the influence of individual SNPs on the MR study. The IVW analysis demonstrated that elevated serum urate levels increased the risk of female infertility (odds ratio [OR] = 1.18, 95% confidence interval [CI]: 1.07-1.33). Furthermore, serum urate levels were found to be associated with infertility due to cervical, vaginal, or other unknown causes (OR = 1.16, 95% CI: 1.06-1.26), also confirmed by other methods. Heterogeneity among instrumental variables was assessed using Cochran's Q-test (p < 0.05), so a random-effects IVW approach was employed in the effects model. The MR-Egger intercept test indicated no presence of horizontal pleiotropy. A "leave-one-out" sensitivity analysis was conducted, demonstrating that no individual SNP had a substantial impact on the overall findings. In the European population, the urate level is significantly and causally associated with an increased risk of female infertility.

Non-adherence to urate lowering therapy in gout after 5 years is related to poor outcomes-results from the NOR-Gout study.

Patients with gout need to adhere to medication over time to achieve good outcomes. We assessed self-reported adherence to medication with urate lowering therapy (ULT) 5 years after a treat-to-target intervention and studied how non-adherence was related to baseline demographic and disease variables. Patients in the NOR-Gout observational study were included after a recent gout flare and serum urate >360 µmol/L. Patients (mean age 56.2 (S.D. 13.6), 94.5% males, 17.2% with tophi) attended tight-control visits over one year with escalating urate lowering therapy using a treat-to-target strategy. Five-year follow-up included the Medication Adherence Report Scale (MARS-5) questionnaire (range 5-25) for adherence. Flares and SUA target achievement were compared for 5-year adherence to medication. At 5-years most of the 163 patients used ULT (95.1%). MARS-5 adherence scores after 5 years were high (median 24, interquartile range 22-25). Patients in the lowest MARS-5 quartile had, compared to the highest quartile, more often a flare during the last year of follow-up (33.3% vs. 9.5%, P=0.004), and reached the 5-yr serum urate treatment target less frequently (45.2% vs. 87.5%, P<0.001). Baseline lower age (OR 0.56, 95%CI 0.39-0.79), non-European origin (OR 0.22, 95%CI 0.06-0.80), lower SF-36 mental health scores (OR 0.94, 95%CI 0.91-0.98) and less joint pain during last flare (OR 0.73, 95%CI 0.58-0.92) were independent risk factors for non-adherence to medication. Patients reported after 5 years high adherence to medication. Non-adherence was related to more flares and less urate target achievement. Younger age and non-European origin were associated with non-adherence.

C4d Is an Independent Predictor of the Kidney Failure in Primary IgA Nephropathy.

Background: C4d deposits are present in a substantial proportion of patients with IgA nephropathy (IgAN), indicating the activation of the lectin pathway (LP) of the complement system. It seems that patients with activated LP have worse renal prognosis. The aim of this study was to investigate the prevalence and prognostic significance of C4d in our cohort of patients with primary IgA nephropathy (pIgAN). Methods: Patients with pIgAN were recruited from a hospital register of kidney biopsies of the Department of Nephrology and Dialysis, Dubrava University Hospital, Zagreb. Additional immunohistochemistry staining for C4d was performed on paraffin-embedded kidney tissue, and patients were stratified into being C4d positive or C4d negative. The clinical and histologic features of patients were analyzed and compared regarding C4d positivity. The primary outcome was defined as kidney failure (KF), and predictor variables of KF and renal survival were analyzed. Results: Of a total of 95 patients with pIgAN included in the study, C4d was present in 43 (45.3%). C4d-positive patients had a higher value of systolic (p = 0.039) and diastolic (p = 0.006) blood pressure at diagnosis as well as higher 24 h proteinuria (p = 0.018), serum urate (p = 0.033), and lower eGFR (p < 0.001). C4d-positive patients had worse renal survival (p < 0.001), higher rates of disease progression to KF (p < 0.001), and higher proteinuria (p < 0.001) and lower eGFR (p < 0.001) at the last follow-up. Glomerular C4d was an independent predictor of disease progression to KF (HR = 5.87 [0.95 CI 1.06-32.44], p = 0.032). Conclusions: C4d is an independent predictor of disease progression in patients with pIgAN. C4d may be used as an additional marker of progressive disease course in IgAN. The therapeutic implications of C4d status in IgAN, particularly in terms of complement inhibitors application, are not yet known.

Baseline Dual-Energy Computed Tomography Urate Volume Predicts Fulfillment of Gout Remission After Two Years of Urate-Lowering Therapy.

This study aimed to identify variables that predict gout remission in people with erosive gout receiving urate-lowering therapy. We analyzed data from a two-year, double-masked randomized-controlled trial of people with erosive gout, randomized to a serum urate target of <0.20 mmol/L or <0.30 mmol/L using oral urate-lowering therapies. All participants had dual-energy computed tomography (DECT) scans of the feet and ankles at baseline. The proportion of participants achieving gout remission according to the 2016 preliminary gout remission criteria and simplified gout remission criteria (without the patient reported outcomes) was analyzed. Logistic regression models were used to evaluate predictors of gout remission in year 2. The preliminary gout remission criteria were fulfilled in 11 of 97 participants (11%) at year 1 and 21 of 92 participants (23%) at year 2. The simplified criteria were fulfilled in 26 of 97 participants (27%) in year 1 and 40 of 92 participants (44%) in year 2. In multivariable regression models, baseline DECT monosodium urate crystal volume was the only significant independent predictor of gout remission at year 2, using either criteria. Each 1-cm3 increase in the baseline DECT monosodium urate crystal volume decreased the odds of fulfilling the 2016 preliminary gout remission criteria (odds ratio [OR] 0.65, 95% confidence interval [CI] 0.46-0.93; P = 0.02) and the simplified gout remission criteria (OR 0.57, 95% CI 0.41-0.78; P < 0.001). In people with erosive gout on urate-lowering therapy, higher baseline DECT monosodium urate crystal volume is associated with lower odds of gout remission after two years of treatment, defined by either the preliminary gout remission criteria or simplified gout remission criteria.

Hyperechoic Spots in the Renal Medulla as a Potential Indicator of Early Gouty Nephropathy

Introduction: The aim of the study was to explore the causes and clinical significance of hyperechoic renal medulla observed by ultrasonography in patients with primary gout. Methods: This study included 2,107 patients with primary gout treated in the Gout Clinic of our hospital from 2016 to 2022. The clinical data and biochemical data of these patients were collected and analyzed. According to the presence or absence of punctate hyperechogenicity in the renal medulla on ultrasound examination, the patients were divided into the hyperechoic medulla (HM) and the normal hypoechoic medulla (NM) groups, and the HM group was further divided into the partial HM (P-HM) and fulfilled HM (F-HM) subgroups according to the distribution range of hyperechogenicity. Results: Among the 2,107 patients with primary gout, 380 had hyperechoic renal medulla on renal ultrasound, including 106 patients with F-HM and 274 with P-HM. There were significant differences in the gout duration, urate arthropathy number, serum urate (SU) level, clinical tophi number, blood urea nitrogen, serum creatinine (sCr), and estimated glomerular filtration rate between the HM and NM groups or between the F-HM and P-HM subgroups (p < 0.05). Multivariate regression analysis showed that the presence of HM was positively correlated with gout duration, urate arthropathy number, gout attack frequency, SU, and sCr. The number of clinical tophi and sCr were closely related to F-HM. Conclusion: Ultrasound examination showed that a high medulla echo in patients with gout was often related to renal function damage. P-HM may be a transitory condition between NM and F-HM in patients with gout.

Dietary Carbohydrates, Genetic Susceptibility, and Gout Risk: A Prospective Cohort Study in the UK.

This study aimed to investigate the associations between carbohydrate intake and gout risk, along with interactions between genetic susceptibility and carbohydrates, and the mediating roles of biomarkers. We included 187,387 participants who were free of gout at baseline and completed at least one dietary assessment in the UK Biobank. Cox proportional hazard models were used to estimate the associations between carbohydrate intake and gout risk. Over a median follow-up of 11.69 years, 2548 incident cases of gout were recorded. Total carbohydrate intake was associated with a reduced gout risk (Q4 vs. Q1: HR 0.67, 95% CI 0.60-0.74), as were total sugars (0.89, 0.80-0.99), non-free sugars (0.70, 0.63-0.78), total starch (0.70, 0.63-0.78), refined grain starch (0.85, 0.76-0.95), wholegrain starch (0.73, 0.65-0.82), and fiber (0.72, 0.64-0.80), whereas free sugars (1.15, 1.04-1.28) were associated with an increased risk. Significant additive interactions were found between total carbohydrates and genetic risk, as well as between total starch and genetic risk. Serum urate was identified as a significant mediator in all associations between carbohydrate intake (total, different types, and sources) and gout risk. In conclusion, total carbohydrate and different types and sources of carbohydrate (excluding free sugars) intake were associated with a reduced risk of gout.

Relationship between serum urate and changes in dual-energy CT monosodium urate crystal volume over 1 year in people with gout: an individual participant data analysis

ObjectivesThe dynamics of monosodium urate (MSU) crystal changes across a range of serum urate concentrations in people with gout are unknown. This study aimed to systematically examine the relationship between...

Caffeine Inhibits Both Basal and Insulin-Activated Urate Transport.

Caffeine, an adenosine receptor antagonist, is a potent central nervous system stimulant that also impairs insulin signaling. Recent studies have suggested that coffee consumption lowers serum urate (SU) and protects against gout by unknown mechanisms. We hypothesized that caffeine lowers SU by affecting activity of urate transporters. We examined the effect of caffeine and adenosine on basal and insulin stimulation of net 14C-urate uptake in the human renal proximal tubule cell line PTC-05 and on individual urate transporters expressed in Xenopus laevis oocytes. We found that caffeine and adenosine efficiently inhibited both basal and insulin stimulation of net 14C-urate uptake mediated by endogenous urate transporters in PTC-05 cells. In oocytes expressing individual urate transporters, caffeine (>0.2 mM) more efficiently inhibited the basal urate transport activity of GLUT9 isoforms, OAT4, OAT1, OAT3, NPT1, ABCG2, and ABCC4 than did adenosine without significantly affecting URAT1 and OAT10. However, unlike adenosine, caffeine at lower concentrations (<0.2 mM) very effectively inhibited insulin activation of urate transport activity of GLUT9, OAT10, OAT1, OAT3, NPT1, ABCG2, and ABCC4 by blocking activation of Akt and extracellular signal-regulated kinase. We postulate that inhibition of urate transport activity of the re-absorptive transporters GLUT9, OAT10, and OAT4 by caffeine is a key mechanism in its urate-lowering effects. Additionally, the ability of caffeine to block insulin-activated urate transport by GLUT9a and OAT10 suggests greater relative inhibition of these transporters in hyperinsulinemia.