Risk of end-stage renal disease associated with gout: a nationwide population study

Untargeted metabolomics analysis of the urinary metabolic signature of acute and chronic gout

BACKGROUND

Gout is a common kind of inflammatory arthritis with metabolic disorders. However, the detailed pathogenesis of gout is complex and not fully clear. We investigated the urine metabolic profiling of gout patients by ultra-performance liquid chromatograph quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS).

METHOD

Urine metabolites were extracted from 26 acute gout patients, 31 chronic gout patients, and 32 healthy controls. Metabolite extracts were analyzed by UPLC-Q-TOF-MS for untargeted metabolomics. The peak area of creatinine was used to correct the content variations of urine samples for the semi-quantitative analysis. The value of variable importance in the projection (VIP) was obtained through the orthogonal partial least squares-discrimination analysis (OPLS-DA), and several differential metabolites were screened out.

RESULTS

The potential metabolic markers of gout in different stages were found based on the t-test. Finally, 18 different metabolites were identified through Human Metabolome Database (HMDB) and Targeted-MS/MS. The receiver operating characteristic (ROC) curve results revealed that all the screened biomarkers exerted high accuracy and diagnostic value. Pathway analysis indicated that the significantly different metabolites were mainly involved in purine metabolism and amino acid metabolism.

CONCLUSION

The identified potential biomarkers are mainly involved in purine metabolism and amino acid metabolism, which leads us to further explore the pathogenesis of gout. This will lead us to further explore the pathogenesis of gout and provide the basis and ideas for the prevention and treatment of gout.

A study on the antioxidant, anti-inflammatory, and xanthine oxidase inhibitory activity of the Artemisia vulgaris L. extract and its fractions

ETHNOPHARMACOLOGICAL RELEVANCE

Vietnamese people use mugwort (Artemisia vulgaris L.) to treat arthritis and gout. Our previous research shows that mugwort contains flavonoids, and its extract possesses antibacterial and anti-inflammatory activities. However, no publications have been on the xanthine oxidase inhibitory activity of mugwort and acute anti-inflammatory activity in vivo.

AIM OF THE STUDY

The study aimed to verify the antioxidant, xanthine oxidase inhibitory, and anti-inflammatory capabilities of mugwort extract in vitro and in vivo, isolate phyto-compounds from potential bioactive fractions, and then evaluate their potential in inhibiting xanthine oxidase.

METHODS

According to established methods, the extract and the active flavonoids were obtained using different chromatographic techniques. DPPH, ABTS, reducing power, and H2O2 elimination were used to evaluate antioxidant activity. The model of LPS-induced RAW264.7 cells was used to measure the inhibition of NO production. The carrageenan-induced paw oedema model was used to assess acute inflammation in mice. In vitro, xanthine oxidase inhibition assay was applied to investigate the effects of extract/compounds on uric acid production. Chemical structures were identified by spectral analysis.

RESULTS

The assessment of the acute inflammatory model in mice revealed that both the 96% ethanol and the 50% ethanol extracts significantly decreased oedema in the mice's feet following carrageenan-induced inflammation. 96% ethanol extract exhibited a better reduction in oedema at the low dose. The analysis revealed that the ethyl acetate fraction had the highest levels of total polyphenols and flavonoids. Additionally, this fraction demonstrated significant antioxidant activity in various assays, such as DPPH, ABTS, reducing power, and H2O2 removal. Furthermore, it displayed the most potent inhibition of xanthine oxidase, an anti-inflammatory activity. Five phytochemicals were isolated and determined from the active fraction such as luteolin (1), rutin (2), apigenin (3), myricetin (4), and quercetin (5). Except for rutin, the other compounds demonstrated the ability to inhibit effective xanthine oxidase compared to standard (allopurinol). Moreover, quercetin (5) inhibited NO production (IC50 21.87 μM).

CONCLUSION

The results indicate that extracts from A. vulgaris effectively suppressed the activity of xanthine oxidase and exhibited antioxidant and anti-inflammatory properties, potentially leading to a reduction in the production of uric acid in the body and eliminating ROS. The study identified mugwort extract and bioactive compounds derived from Artemisia vulgaris, specifically luteolin, apigenin, and quercetin, as promising xanthine oxidase inhibitors. These findings suggest that further development of these compounds is warranted. At the same time, the above results also strengthen the use of mugwort to treat gout disease in Vietnam.

Albuminuria-based stratification of end-stage kidney disease progression and mortality with sodium-glucose cotransporter 2 inhibitors (SGLT2i): A retrospective cohort study in type 2 diabetes and chronic kidney disease

BACKGROUND

Clinical trials have shown the kidney-protective benefits of sodium-glucose cotransporter 2 inhibitors (SGLT2i). However, their real-world impact, particularly across varying levels of albuminuria, remains less well understood. This study aimed to evaluate the association of SGLT2i, compared with other oral glucose-lowering drugs, with end-stage kidney disease (ESKD) progression in patients with type 2 diabetes and chronic kidney disease (CKD) stratified by urine albumin-to-creatinine ratio (UACR) levels.

METHODS

Using data from a national database spanning from 2016 to 2021, the study included patients with type 2 diabetes and CKD with estimated glomerular filtration rates (eGFRs) below 60 mL/min/1.73 m2 and who started on SGLT2i or other oral glucose-lowering drugs. Patients were stratified into groups by UACR ≥300 mg/g and <300 mg/g. Propensity score matching was used to minimize confounding, and progression to ESKD was evaluated using competing risks and Cox proportional-hazards models. All-cause mortality was also analyzed.

RESULTS

Following propensity score matching, 18,514 patients in the severely increased albuminuria group (UACR ≥300 mg/g) were tracked, with 2.6% progressing to ESKD over 3 years. In contrast, only 0.3% of the 26,946 patients with UACR <300 mg/g progressed to ESKD. SGLT2i use was associated with a 30% reduction in risk of ESKD progression, compared with the use of other oral glucose-lowering drugs, in the severely increased albuminuria group (hazard ratio[HR]: 0.70, 95% confidence interval [CI]: 0.61-0.80). In the lower albuminuria group, no significant association was evident, though there was a nonsignificant trend toward protection over time. A consistent reduction in mortality risk was observed across all albuminuria levels.

CONCLUSIONS

SGLT2i are associated with a reduction in the progression to ESKD among patients with severely increased albuminuria, with less pronounced effects observed in those with lower albuminuria levels, suggesting variability in renal outcomes based on albuminuria severity. The consistent survival benefit across all albuminuria levels supports the potential utility of SGLT2i in diabetes and CKD treatment strategies, emphasizing the need for more targeted research.

Impact of Chronic Kidney Disease and Gout on End-Stage Renal Disease in Type 2 Diabetes: Population-Based Cohort Study

BACKGRUOUND

We examined the impact of gout on the end-stage renal disease (ESRD) risk in patients with type 2 diabetes mellitus (T2DM) and determined whether this association differs according to chronic kidney disease (CKD) status.

METHODS

Using the Korean National Health Insurance Service, this nationwide cohort study enrolled 847,884 patients with T2DM who underwent health checkups in 2009. Based on the presence of CKD (estimated glomerular filtration rate <60 mL/min/1.73 m2) and gout (two outpatient visits or one hospitalization within 5 years), patients were classified into four groups: CKD-Gout-, CKD- Gout+, CKD+Gout-, and CKD+Gout+. Patients with incident ESRD were followed up until December 2018.

RESULTS

Among 847,884 patients, 11,825 (1.4%) experienced progression to ESRD. ESRD incidence increased in the following order: 0.77 per 1,000 person-years (PY) in the CKD-Gout- group, 1.34/1,000 PY in the CKD-Gout+ group, 8.20/1,000 PY in the CKD+Gout- group, and 23.06/1,000 PY in the CKD+Gout+ group. The presence of gout modified the ESRD risk in a status-dependent manner. Hazard ratios (HR) were 1.49 (95% confidence interval [CI], 1.32 to 1.69) and 2.24 (95% CI, 2.09 to 2.40) in patients without and with CKD, respectively, indicating a significant interaction (P<0.0001). The CKD+Gout+ group had a markedly higher risk of developing ESRD (HR, 18.9; 95% CI, 17.58 to 20.32) than the reference group (CKD-Gout-).

CONCLUSION

Gout substantially enhances the risk of ESRD, even in the absence of CKD. Concurrent CKD and gout synergistically increase the risk of ESRD. Therefore, physicians should carefully screen for hyperuricemia to prevent progression to ESRD.

The Prevalence and Factors Associated with Coronary Heart Disease in Patients with Gout

Gout is associated with increased risk of cardiovascular disease (CVD) morbidity and mortality. Therefore, an association between coronary heart disease (CHD) and gout deserves careful examination.

AIM

. The aim of this study was to determine the prevalence of CHD and factors associated with CHD in patients (pts) with gout.

MATERIALS AND METHODS

. The study involved 286 male patients with gout, age 51.2 [42.8; 59.4] years (ys), disease duration 6.2 [3.8; 12.1] ys. All patients underwent standard clinical examination screening traditional risk factors (TRFs) of CVDs. We estimated the adjusted odds ratio (OR) and 95% confidence interval (95% CI).

RESULTS

. CHD was found in 111 out of the 286 pts (38.8%), MI had a history in 29.7%. Compared to individuals with CHD, participants without CHD were older (56.7[52.1; 61.1] vs 46.2[40.6; 53.4] ys), had longer duration of gout (9.3[4.7; 15.1] vs 5.6[3.3; 9.7] ys) (for all p < 0.05). Abdominal obesity (OR, 3.6; 95% CI, 1.2-10.9), family history of CHD (OR, 2.2; 95% CI, 1.3-3.7), disease duration of gout more 10 ys (OR, 2.8; 95% CI, 1.6-4.7), age of gout onset < 35 ys (OR, 5.5; 95% CI, 2.6-11.7), intraosseous tophi (OR, 3.03; 95% CI, 1.8-5.01), nephrolithiasis (OR, 1.7; 95% CI, 1.04-3.04), renal failure (OR, 5.6; 95% CI, 2.7-11.4), serum total cholesterol (TC), (OR, 1.6; 95% CI, 1.0-2.8), serum creatinine (OR, 2.5; 95% CI, 1.2-5.1), increased the risk for CHD in patients with a gout.

CONCLUSIONS

. The prevalence of CHD was 38.8% among individuals with gout (one-third of patients had a history of MI 29.7%). Our study showed that both TRFs of CVD and the severity of gout and a history of renal failure contribute to the development of CHD in patients with gout.

A consensual machine-learning-assisted QSAR model for effective bioactivity prediction of xanthine oxidase inhibitors using molecular fingerprints

Xanthine oxidase inhibitors (XOIs) have been widely studied due to the promising potential as safe and effective therapeutics in hyperuricemia and gout. Currently, available XOI molecules have been developed from different experiments but they are with the wide structure diversity and significant varying bioactivities. So it is of great practical significance to present a consensual QSAR model for effective bioactivity prediction of XOIs based on a systematic compiling of these XOIs across different experiments. In this work, 249 XOIs belonging to 16 scaffolds were collected and were integrated into a consensual dataset by introducing the concept of IC50 values relative to allopurinol (RIC50). Here, extended connectivity fingerprints (ECFPs) were employed to represent XOI molecules. By performing effective feature selection by machine-learning method, 54 crucial fingerprints were indicated to be valuable for predicting the inhibitory potency (IP) of XOIs. The optimal predictor yields the promising performance by different cross-validation tests. Besides, an external validation of 43 XOIs and a case study on febuxostat also provide satisfactory results, indicating the powerful generalization of our predictor. Here, the predictor was interpreted by shapely additive explanation (SHAP) method which revealed several important substructures by mapping the featured fingerprints to molecular structures. Then, 15 new molecules were designed and predicted by our predictor to show superior IP than febuxostat. Finally, molecular docking simulation was performed to gain a deep insight into molecular binding mode with xanthine oxidase (XO) enzyme, showing that molecules with selenazole moiety, cyano group and isopropyl group tended to yield higher IP. The absorption, distribution, metabolism, excretion and toxicity (ADMET) prediction results further enhanced the potential of these novel XOIs as drug candidates. Overall, this work presents a QSAR model for accurate prediction of IP of XOIs, and is expected to provide new insights for further structure-guided design of novel XOIs.

Association between the initial dose urate-lowering drugs and gout flares in adult males with gout

OBJECTIVES

Frequent gout attacks in the initial introduction of urate-lowering therapy (ULT) are significant causes of poor drug adherence and ULT discontinuation. Initial low-dose urate-lowering drugs may be effective in reducing gout flares, however robust evidence is sparse. The aim of this study was therefore to assess the association of initial dose urate-lowering drugs with gout flares in adult males with gout during the initial introduction of ULT.

METHODS

This cohort study obtained data on consecutive gout patients from a single-centre gout cohort study from August 2017 to October 2020. A standard questionnaire was applied to collect demographic and clinical information, and biochemical parameters were tested on the same day. The primary endpoint was to estimate the association of initial dose febuxostat with gout flares, using Cox hazard models with inverse probability of treatment weighting (IPTW).

RESULTS

A total of 582 gout patients were included in this study. During the 6-week follow-up, 71 (12.2%) patients suffered gout flares. In the main analysis using Cox hazard models with IPTW, compared with colchicine prophylaxis, initial low-dose febuxostat alone had no statistical significance with the increased risk of gout flares [hazard ratio (HR) 1.26; 95% CI 0.58, 2.72], while initial high-dose febuxostat was associated with an increased risk of gout flares (HR 3.08; 95% CI 1.34, 7.07).

CONCLUSIONS

This observational study demonstrated that initial low-dose febuxostat was equally effective in preventing gout flares as colchicine prophylaxis, while initial high-dose febuxostat alone was associated with an increased risk of gout flares.

Relationship between gout, hyperuricemia, and obesity-does central obesity play a significant role?-a study based on the NHANES database

BACKGROUND

Our objective was to evaluate how various measures of obesity, such as body mass index(BMI), body roundness index(BRI), and weigh adjusted waist index(WWI), influence urate levels, prevalence of gout and to compare the disparities among these obesity indicators.

METHODS

By analyzing the 2001-2018 National Health and Nutrition Examination Survey (NHANES), we assessed the relationship between BMI, WWI, and BRI indices and urate levels, hyperuricemia, and the prevalence of gout. Smoothed curve fitting was used to determine whether there was a nonlinear relationship between BMI,WWI, and BRI indices and urate levels, hyperuricemia, and the prevalence of gout, and threshold effects analysis was used to test this relationship. We also used ROC curves to determine the diagnostic efficacy of BMI, WWI, and BRI on the prevalence of hyperuricemia and gout.

RESULTS

The study incorporated a total of 29,310 participants aged over 20 years, out of which 14,268 were male. Following the adjustment for the pertinent confounding factors, it was observed that higher levels of BMI, WWI, and BRI were significantly associated with a gradual and dose-dependent increase in urate levels. In the sensitivity analysis, each unit increment in BMI, WWI, and BRI levels exhibited an 8%, 72%, and 26% respective elevation in the risk of hyperuricemia, as well as a 5%, 31%, and 15% respective increase in the risk of gout. Dose-response curves provided evidence of a linear positive correlation between BMI, WWI, BRI, and urate levels, as well as the prevalence of hyperuricemia and gout. Based on the response from the ROC curve, overall, the diagnostic efficacy of BRI for hyperuricemia and gout surpasses that of BMI.

CONCLUSION

The central obesity indices WWI and BRI levels are superior to BMI in detecting the prevalence of urate levels, hyperuricemia, and gout, and although a clear causal relationship has not yet been established, it is important to recognize the impact of central obesity on uric acid levels and to give it due attention.

Comparison Between Early-Onset and Common Gout: A Systematic Literature Review

INTRODUCTION

Gout is an inflammatory, metabolic disease associated with a high comorbidity burden including cardiovascular disease, hypertension, type 2 diabetes, hyperlipidemia, renal disease, and metabolic syndrome. Approximately 9.2 million Americans have gout, making prognosis and treatment outcome predictors highly important. About 600,000 Americans have early-onset gout (EOG), generally defined as first gout attack at ≤ 40 years of age. However, data on EOG clinical features, comorbidity profile, and treatment response are sparse; this systematic literature review provides insight.

METHODS

PubMed and American College of Rheumatology (ACR)/European Alliance of the Associations for Rheumatology (EULAR) abstract archives were searched for early-onset gout, "early onset gout," and ("gout" AND "age of onset"). Duplicate, foreign language, single case report, older (before 2016), and irrelevant/data insufficient publications were excluded. The age of diagnosis categorized patients as having common gout (CG, generally > 40 years) or EOG (generally ≤ 40 years). Applicable publications were extensively reviewed/discussed among authors for inclusion/exclusion consensus.

RESULTS

A total of 283 publications were identified, with 46 (35 articles, 10 abstracts) reviewed and 17 (12 articles, 5 abstracts) ultimately included. Eleven reported clinical characteristics, with 6 EOG-CG retrospective/cross-sectional comparisons. Gout diagnosis preceded cardiometabolic comorbidity and renal comorbidities were less prevalent in EOG than CG patients. EOG patients had more severe disease (more gout flares, polyarticular disease), higher pre-therapy serum urate (SU), and worse oral urate-lowering therapy response. Genetics-focused publications reported higher incidences of dysfunctional urate transporter mutations in EOG patients.

CONCLUSIONS

This review suggests that EOG is more recalcitrant to urate-lowering therapy, is associated with urate transporter defects, and carries heavy disease burden. Therefore, early rheumatology referral and urate-lowering in a treat-to-target fashion may benefit EOG patients. Interestingly, EOG patients had fewer cardiometabolic comorbidities at diagnosis than CG patients, presenting a potential "window of opportunity" to attenuate cardiometabolic comorbidity development with SU control. Preventing gout-related suffering and health burden is particularly important in these young EOG patients who will live with gout and its sequelae for decades.

Comparison of benzbromarone and allopurinol on the risk of chronic kidney disease in people with asymptomatic hyperuricemia

OBJECTIVE

The objective of the study was to compare the relative effects of benzbromarone and allopurinol on the risk of developing chronic kidney disease in persons with asymptomatic hyperuricemia.

METHODS

A retrospective cohort study was conducted to analyze a 2003-2015 national database including all claims data of 2 million beneficiaries in Taiwan. Asymptomatic hyperuricemia was defined as follows: persons using urate-lowering drugs who never developed gout flares. The benzbromarone group included persons ages 20-84 that had asymptomatic hyperuricemia and received benzbromarone alone. The allopurinol group included persons ages 20-84 that had asymptomatic hyperuricemia and received allopurinol alone. The maximum follow-up time was set as 5 years in this study. The main outcome was defined as follows: persons were newly diagnosed with chronic kidney disease. A Cox proportional hazards regression analysis was performed to test the association between variables and the risk of chronic kidney disease.

RESULTS

After propensity score matching, 9107 persons in the benzbromarone group and 4554 persons in the allopurinol group were eligible for the study. Approximately 71% of the study subjects were males. The mean age was 56 years old. The incidence rate of chronic kidney disease was lower in the benzbromarone group than in the allopurinol group (1.18 versus 1.99/per 100 person-years, incidence ratio = 0.60, and 95% confidence interval = 0.52-0.68).The Cox proportional hazards regression analysis disclosed that after adjusting for co-variables, there was a decreased risk of developing chronic kidney disease in the benzbromarone group as compared with the allopurinol group (hazard ratio = 0.59, 95% confidence interval = 0.52-0.67 and P<0.001).

CONCLUSIONS

The use of benzbromarone is associated with a lower hazard of developing chronic kidney disease as compared to allopurinol use among persons ages 20-84 with asymptomatic hyperuricemia. More studies are needed to confirm our findings.

Effect of febuxostat on adverse events and mortality in gout in Taiwan: An interrupted time series analysis

OBJECTIVES

To evaluate the influence of febuxostat on adverse events and mortality in gout.

METHODS

We retrospectively enrolled patients with newly diagnosed gout and prescribed urate-lowering therapy between 2006 and 2017 from the Taiwan National Health Insurance Database. These patients were divided into 2 groups: with and without comorbidities (n = 294 847 and 194 539). An interrupted time series analysis with adjustments for demographics, comorbidities, and comedication by propensity score-based stabilized weights was used to compare the trend of adverse events and mortality before vs after febuxostat was introduced in 2012.

RESULTS

The proportion of febuxostat use gradually increased from 0% in 2012 to 30% in those with comorbidities and 10% in those without comorbidities in 2017. Allopurinol use decreased from 30% in 2012 to 10% in 2017. The slope of the 1-year incidence rate of Stevens-Johnson syndrome (SJS) or toxic epidermal necrolysis (TEN) (per 10 000 patients) significantly reduced after 2012 in those with and without comorbidities (-0.375 per quarter, P = .015 and -.253 per quarter, P = .049). The slope of the 3-year incidence rate of acute myocardial infarction (AMI) (per 1000 patients), percutaneous coronary intervention (PCI) (per 1000 patients), and all-cause mortality (per 100 patients) significantly increased after 2012 in those with comorbidities (+0.207 per quarter, P = .013; +.389 per quarter, P = .002; +.103 per quarter, P = .001).

CONCLUSIONS

Febuxostat may reduce SJS and TEN in all gout patients but increase AMI, PCI, and all-cause mortality in gout patients with comorbidities.

The Singapore Experience With Uncontrolled Gout: Unmet Needs in the Management of Patients

Gout is the most common type of inflammatory arthritis, and its impact on cardiovascular health and quality of life is often underestimated. The prevalence and incidence of gout are increasing globally. Further, ischemic heart disease (IHD) and chronic kidney disease (CKD) are prevalent in gout patients. Some unmet needs for gout management include physicians' low initiation rate of urate-lowering therapy (ULT) and poor treatment adherence in patients with gout. There is also a lack of randomized controlled trials that establish safe doses of acute and long-term treatment for gout, particularly in patients with IHD and stage 4 CKD and above (including end-stage renal failure). Furthermore, there is also a lack of studies showing optimal serum uric acid (SUA) target and validated clinical outcome measures, including disease activity and remission criteria for gout tailored to treat-to-target approaches and the high cost of newer gout medications. The causal relationship between asymptomatic hyperuricemia or gout with comorbidities such as IHD and CKD has yet to be fully elucidated. There is a pressing need for collaborative international efforts to address the overall suboptimal management of gout.

A Randomized, Placebo-Controlled Study of Methotrexate to Increase Response Rates in Patients with Uncontrolled Gout Receiving Pegloticase: Primary Efficacy and Safety Findings

OBJECTIVE

To assess efficacy, safety, pharmacokinetics, and immunogenicity of pegloticase plus methotrexate (MTX) versus pegloticase plus placebo cotreatment for uncontrolled gout in a randomized, placebo-controlled, double-blind trial.

METHODS

This study included adults with uncontrolled gout, defined as serum urate ≥7 mg/dl, oral urate-lowering therapy failure or intolerance, and presence of ongoing gout symptoms including ≥1 tophus, ≥2 flares in the past 12 months, or gouty arthritis. Key exclusion criteria included MTX contraindication, current immunosuppressant use, G6PDH deficiency, and estimated glomerular filtration rate <40 ml/minute/1.73 m² . Patients were randomized 2:1 to 52 weeks of pegloticase (8 mg biweekly) with either oral MTX (15 mg/week) or placebo. The primary end point was the proportion of treatment responders during month 6 (defined as serum urate <6 mg/dl for ≥80% of visits during weeks 20-24). Efficacy was evaluated in all randomized patients (intent-to-treat population), and safety was evaluated in all patients receiving ≥1 blinded MTX or placebo dose.

RESULTS

A total of 152 patients were randomized, 100 to receive pegloticase plus MTX, 52 to receive pegloticase plus placebo. Significantly higher treatment response occurred during month 6 in the MTX group versus the placebo group (71.0% [71 of 100 patients] versus 38.5% [20 of 52 patients], respectively; between-group difference 32.3% [95% confidence interval 16.3%, 48.3%]) (P < 0.0001 for between-group difference). During the first 6 months of pegloticase plus MTX or pegloticase plus placebo treatment, 78 (81.3%) of 96 MTX patients versus 47 (95.9%) of 49 placebo patients experienced ≥1 adverse event (AE), most commonly gout flare (64 [66.7%] of 96 MTX patients and 34 [69.4%] of 49 placebo patients). Reports of AEs and serious AEs were comparable between groups, but the infusion reaction rate was considerably lower with MTX cotherapy (4.2% [4 of 96 MTX patients, including 1 patient who had anaphylaxis]) than with placebo cotherapy (30.6% [15 of 49 placebo patients, 0 who had anaphylaxis]) (P < 0.001). Antidrug antibody positivity was also lower in the MTX group.

CONCLUSION

MTX cotherapy markedly increased pegloticase response rate over placebo (71.0% versus 38.5%) during month 6 with no new safety signals. These findings verify higher treatment response rate, lower infusion reaction incidence, and lower immunogenicity when pegloticase is coadministered with MTX.

A multicentre, efficacy and safety study of methotrexate to increase response rates in patients with uncontrolled gout receiving pegloticase (MIRROR): 12-month efficacy, safety, immunogenicity, and pharmacokinetic findings during long-term extension of an open-label study

BACKGROUND

Publications suggest immunomodulation co-therapy improves responder rates in uncontrolled/refractory gout patients undergoing pegloticase treatment. The MIRROR open-label trial showed a 6-month pegloticase + methotrexate co-therapy responder rate of 79%, compared to an established 42% pegloticase monotherapy responder rate. Longer-term efficacy/safety data are presented here.

METHODS

Uncontrolled gout patients (serum urate [SU] ≥ 6 mg/dL and SU ≥ 6 mg/dL despite urate-lowering therapy [ULT], ULT intolerance, or functionally-limiting tophi) were included. Patients with immunocompromised status, G6PD deficiency, severe kidney disease, or methotrexate contraindication were excluded. Oral methotrexate (15 mg/week) and folic acid (1 mg/day) were administered 4 weeks before and during pegloticase therapy. Twelve-month responder rate (SU < 6 mg/dL for ≥ 80% during month 12), 52-week change from baseline in SU, and extended safety were examined. Efficacy analyses were performed for patients receiving ≥ 1 pegloticase infusion. Pharmacokinetics (PK)/anti-drug antibodies (ADAs) were examined and related to efficacy/safety findings.

RESULTS

Fourteen patients were included (all male, 49.3 ± 8.7 years, 13.8 ± 7.4-year gout history, pre-therapy SU 9.2 ± 2.5 mg/dL). Three patients were non-responders and discontinued study treatment before 24 weeks, one patient exited the study per protocol at 24 weeks (enrolled prior to treatment extension amendment), and 10 remained in the study through week 52. Of the 10, 8 completed 52 weeks of pegloticase + methotrexate and were 12-month responders. The remaining two discontinued pegloticase + methotrexate at week 24 (met treatment goals) and stayed in the study under observation (allopurinol prescribed at physicians' discretion); one remained a responder at 12 months. At 52 weeks, change from baseline in SU was - 8.2 ± 4.1 mg/dL (SU 1.1 ± 2.4 mg/dL, n = 10). Gout flares were common early in treatment but progressively decreased while on therapy (weeks 1-12, 13/14 [92.9%]; weeks 36-52, 2/8 [25.0%]). One patient recovered from sepsis (serious AE). Two non-responders developed high ADA titers; fewer patients had trough concentrations (Cmin) below the quantitation limit (BQL), and the median Cmin was higher (1.03 µg/mL vs. BQL) than pegloticase monotherapy trials.

CONCLUSIONS

Pegloticase + methotrexate co-therapy was well-tolerated over 12 months, with sustained SU lowering, progressive gout flare reduction, and no new safety concerns. Antibody/PK findings suggest methotrexate attenuates ADA formation, coincident with higher treatment response rates.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03635957 . Registered on 17 August 2018.

A glance into the future of gout

Gout is characterized by monosodium urate (MSU) crystal deposits in and within joints. These deposits result from persistent hyperuricaemia and most typically lead to recurrent acute inflammatory episodes (gout flares). Even though some aspects of gout are well characterized, uncertainties remain; this upcoming decade should provide further insights into many of these uncertainties. Synovial fluid analysis allows for the identification of MSU crystals and unequivocal diagnosis. Non-invasive methods for diagnosis are being explored, such as Raman spectroscopy and imaging modalities. Both ultrasound and dual-energy computed tomography (DECT) allow the detection of MSU crystals; this not only provides a mean of diagnosis, but also has furthered gout knowledge defining the presence of a preclinical deposition in asymptomatic hyperuricaemia. Scientific consensus establishes the beginning of gout as the beginning of symptoms (usually the first flare), but the concept is currently under review. For effective long-term gout management, the main goal is to promote crystal dissolution treatment by reducing serum urate below 6 mg/dL (or 5 mg/dL if faster crystal dissolution is required). Current urate-lowering therapies' (ULTs) options are limited, with allopurinol and febuxostat being widely available, and probenecid, benzbromarone, and pegloticase available in some regions. New xanthine oxidase inhibitors and, especially, uricosurics inhibiting urate transporter URAT1 are under development; it is probable that the new decade will see a welcomed increase in the gout therapeutic armamentarium. Cardiovascular and renal comorbidities are common in gout patients. Studies determining whether optimal treatment of gout will positively impact these comorbidities are currently lacking, but will hopefully be forthcoming. Overall, the single change that will most impact gout management is greater uptake of international rheumatology society recommendations. Innovative strategies, such as nurse-led interventions based on these recommendations have recently demonstrated treatment success for people with gout.

Stroke Risk in Patients with Gout: A Nationwide Retrospective Cohort Study in Taiwan

Objectives: To estimate stroke risk in Taiwanese patients with gout. Methods: We enrolled patients from the Taiwan National Health Insurance Database, with gout diagnosed from 2000 to 2008, and followed them up until December 2018. This cohort was propensity score-matched according to birth year, sex, the date of diagnosis of gout, comorbidities, and co-medications with individuals without gout (controls) (n = 310,820 in each group). Stroke was defined as the primary diagnosis at discharge after the index date. To evaluate ischemic and hemorrhagic stroke risks, we calculated their incidence, hazard ratio (HR), and two-year moving average incidence rate. Results: The incidence (95% CI) and HR of ischemic stroke were lower in the gout group than in the control group in the first 3 years (incidence: 4.74 [4.60–4.88] vs. 5.17 [5.03–5.32] per 1000 person-years; HR: 0.92 [0.88–0.96]), then became significantly higher than in the control group after 3 years (incidence: 4.10 [4.04–4.16] vs. 3.81 [3.75–3.87] per 1000 person-years; HR: 1.08 [1.05–1.10]). Similarly, the incidence (95% CI) and HR of hemorrhagic stroke was lower in the gout group than in the control group in the first 3 years (incidence: 1.51 [1.43–1.59] vs. 1.70 [1.62–1.79] per 1000 person-years; HR: 0.88 [0.82–0.92]), then became significantly higher than in controls after 3 years (incidence: 1.43 [1.39–1.46] vs. 1.26 [1.22–1.29] per 1000 person-years; HR: 1.14 [1.10–1.18]). Conclusions: In Taiwan, patients with gout had higher risks of ischemic and hemorrhagic stroke after 3 years.

Serum uric acid concentration is associated with hyperhomocysteinemia in hypertensive Chinese adults

PURPOSE

This study is to investigate the correlation between serum uric acid levels and hyperhomocysteinemia Chinese adult patients with hypertension.

METHODS

We enrolled 981 hypertensive patients, including unmedicated hypertensives, in our study. There were 453 patients with hyperhomocysteinemia (hyperhomocysteinemia hypertension group) and 528 without it (ordinary hypertension group). We collected histories of coronary heart disease, diabetes, and smoking and tested patients' BMI, blood pressure, fasting serum uric acid, serum total cholesterol, triglycerides, low-density lipoprotein cholesterol, serum creatinine, and homocysteine. Subjects were stratified into four groups according to their serum uric acid quartiles: Q1 group, 249 cases (≤268 μmol/L); Q2 group, 245 cases (269-322 μmol/L); Q3 group, 244 cases (323-378 μmol/L); and Q4 group, 243 cases (≥379 μmol/L). We employ logistic regression analysis to investigate the relationship between serum uric acid levels and the risk of hyperhomocysteinemia in patients with hypertension.

RESULTS

We find that there were significant differences in gender distribution, serum uric acid, BMI, serum creatinine, total cholesterol, and diastolic blood pressure between the two groups (P < 0.05). The prevalence of hyperhomocysteinemia in groups Q1 through Q4 was 26.91% (67/249), 45.31% (111/245), 47.01% (117/244), and 65.02% (158/243), respectively, after adjusting for relevant factors, we find that the risk of hyperhomocysteinemia in the Q4 group was significantly higher than that in the Q1 group (odds ratio = 3.00, 95% confidence interval: 1.83-4.93).

CONCLUSION

We find evidence that an elevated serum uric acid level is an independent indicator for hyperhomocysteinemia in patients with hypertension.

Evaluation of renal microperfusion in hyperuricemic nephropathy by Contrast-Enhanced Ultrasound imaging

Diagnostic tools for the early detection of renal injury caused by hyperuricemia are still lacking. Here, we investigated whether contrast-enhanced ultrasound (CEUS) could be used as a diagnostic tool for hyperuricemic nephropathy (HN). In the HN rat model, CEUS detected a significant decline in renal cortical perfusion compared with that in control rats. Peak intensity (PI) values correlated significantly with serum KIM-1 levels and fibrosis scores in HN rats. An early decline in PI values was also observed in chronic kidney disease (CKD) stage 1 patients with HN compared with the controls (61.1±4.52 dB versus 65.80±7.10 dB) and correlated with renal function in the patients with HN. In contrast, an increase in time to reach PI values was detected in HN patients with stage 1 CKD (15.14±1.75 s versus 14.52±4.75 s) and was more pronounced in CKD stage 4 patients (67.32±3.29 s). CEUS was able to detect abnormal renal perfusion in early CKD with HN, which correlated with renal function decline, suggesting that CEUS could be used as a noninvasive tool for assessing renal function in patients with HN.

The Negative Association Between NAFLD Severity and CKD in a Non-Diabetic Gouty Population

Nonalcoholic fatty liver disease (NAFLD) and chronic kidney disease (CKD) share common pathogenic mechanisms and risk factors. We aim to evaluate the association between NAFLD and CKD in a non-diabetic gouty population. The retrospective cross sectional study was performed on 1049 non-diabetic gouty participants, who were hospitalized between 2014 and 2020, across 4 districts in Shandong, China. Demographic and clinical characteristics of the study population were collected. The odds ratios (OR) and corresponding 95% confidence intervals (CI) about the NAFLD severity determined by ultrasonography were obtained by multiple logistic regression analysis. An unexpectedly inverse relationship was found between NAFLD severity and the risk of CKD in people with gout. Multivariate logistic regression analysis demonstrated that a higher degree of NAFLD severity is independently associated with a lower risk of CKD in people with gout, after adjusted for age, sex, smoking, gout duration, and metabolic risk factors including obesity, hypertension, hyperglycemia, hyperuricemia, and dyslipidemia, with OR 0.392 (95% CI 0.248-0.619, p<0.001), 0.379 (95% CI 0.233-0.616, p<0.001) and 0.148 (95% CI 0.043-0.512, p=0.003) in participants with mild, moderate, and severe NAFLD, respectively, compared to those without NAFLD. We also observed a weakened association of serum uric acid (SUA) with metabolic risk factors and NAFLD under circumstances of CKD in people with gout (r=-0.054, p=0.466). In conclusion, the presence and severity of NAFLD were negatively associated with the risk of CKD in the non-diabetic gouty population.

Analysis of Risk Factors for Changes in the Renal Two-Dimensional Image in Gout Patients

OBJECTIVE

To explore the effects of different blood uric acid levels in gout patients on the two-dimensional image of the kidney and the risk factors for gout-related kidney damage for providing clinical evidence to enable early prevention and treatment of gout-related kidney damage.

METHODS

We obtained information of 227 patients with primary gout and estimated the association between two-dimensional kidney images and clinical indicators using binary logistic regression.

RESULTS

Our study showed that different uric acid levels, age, disease course, cystatin C (CysC) level, and γ-glutamyl transpeptidase level were correlated with echo of the renal medulla (P < 0.05). CysC level was correlated with the renal cortex thickness and kidney stones in different uric acid-level groups (P < 0.05). Disease course, aspartate transaminase (AST) level, creatinine (CREA) level, and tophi were risk factors for renal cortex thinning in gout patients (P = 0.045, 0.026, 0.004, 0.006, respectively). The disease course, platelet (PLT) count, and high-density lipoprotein (HDL-C) level were risk factors for kidney stone formation in gout patients (P = 0.037, 0.022, 0.023, respectively), while CysC level and C-reactive protein (CRP) level were risk factors for increased renal medulla echo in these patients (P = 0.022, 0.028, respectively).

CONCLUSION

Our study revealed disease course, AST level, CREA level, tophi, PLT count, HDL-C level, CysC level and CRP level may be important predictors of renal image changes.

Association of low-level environmental exposure to cadmium and lead with gout flare using a cohort study design

Cadmium (Cd) and lead (Pb) are toxic heavy metals with endocrine-disrupting properties. We investigated the associations of low-level environmental exposure to Cd/Pb and gout status (intercritical gout, gout flare and combined gout) in a cohort study. We measured by ICP-MS the levels of Cd and Pb in blood (Cd-B and Pb-B) and urine (Cd-U and Pb-U) from 408 participants with blood and 346 participants with urine samples recruited from a hospital gout clinic. The median levels of Cd-B and Pb-B (in μg/L) in the gout flare group were 0.87 (range 0.41-2.49) and 31.54 (25.38-41.46), respectively, and the median levels of Cd-U and Pb-U in the gout flare group were 1.05 (0.69-1.91) and 3.86 (3.49-4.44), respectively. These medians were significantly higher than those in the control or intercritical groups (P < 0.05). For Cd-B in tertile 2 (T2) and Cd-U in tertile 3, Cd levels were significantly associated with gout flare status compared to the reference tertile 1 (OR = 4.3, P = 0.041 and OR = 25.1, P = 0.002, respectively) after adjustment under Model 3. For Pb-U, the risk of gout flare status was significantly higher in T2 (OR = 51.0, P = 0.002) compared to the T1 under Model 3. Our results show that median levels of Cd-B, Pb-B, Cd-U and Pb-U in the gout flare group were significantly higher than participants without gout or with gout but in the intercritical period. We provide evidence that the risk of gout flare status is associated with increased Cd levels, and that blood and urine levels of Cd are a risk factor for gout flare status.

Sesquiterpene lactones from Lychnophora species: Antinociceptive, anti-inflammatory, and antioxidant pathways to treat acute gout

ETHNOPHARMACOLOGICAL RELEVANCE

Lychnophora trichocarpha and Lychnophora passerina are species used in folk medicine to treat inflammation, pain, and rheumatism. Previous studies have demonstrated the anti-inflammatory effect of ethanol extracts of these species and identified that sesquiterpene lactones contribute to this activity.

AIM OF THE STUDY

Gout is an acute inflammatory arthritis caused by the deposition of monosodium urate (MSU) crystals in joints. Inflammation in joints induces oxidative stress in defense cells, releasing pro-inflammatory mediators. This study has three objectives: (1) to demonstrate the effects of sesquiterpene lactones lychnopholide and eremantholide C isolated from L. trichocarpha and goyazensolide isolated from L. passerina on arthritis induced by MSU crystals in C57BL6 mice; (2) to determine whether or not these compounds can inhibit the migration of neutrophils and the release of TNF-α and IL-1β cytokines in the inflammation region; and (3) to evaluate the effects of sesquiterpene lactones on the activities of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) in the cartilage of C57BL/6 mice with gouty arthritis.

MATERIALS AND METHODS

The anti-inflammatory, antinociceptive, and antioxidant activities of sesquiterpene lactones in C57BL/6 mice with MSU crystal-induced arthritis were evaluated. In our experimental model, the mice were injected with MSU crystals in the tibiofemoral joint to induce arthritis and then treated with indomethacin, vitamin C, and sesquiterpene lactones. Nociception was evaluated before and after inflammation induction and treatments, neutrophil migration, IL-1β and TNF-α concentrations, and SOD and CAT activities.

RESULTS

Sesquiterpene lactones exerted an anti-inflammatory effect by inhibiting neutrophil migration and TNF-α production. These compounds also demonstrated antinociceptive and antioxidant activities.

CONCLUSION

Lychnopholide, eremantholide C, and goyazensolide improved the inflammation induced by MSU crystals by inhibiting the migration of neutrophils to the inflamed area and by blocking the release of the pro-inflammatory cytokine TNF-α. In addition, sesquiterpene lactones reduced oxidative stress by activating SOD and CAT. These results suggest that sesquiterpene lactones have anti-gout activity through the inflammation, pain, and oxidative stress pathways.

The risk and severity of stroke in patients with atrial fibrillation and gout: A National Representative Database study

BACKGROUND

It has been shown that gout is associated with left atrium remodeling and a pro-inflammatory state leading to the development of atrial fibrillation (AF). There is limited evidence whether gout increases the risk of stroke in patients with AF. We assessed the incidence of gout and the risk of stroke in patients with AF.

METHODS

This is a retrospective cohort study using the 2016 US National Inpatient Sample (NIS) based on ICD-10 codes. The outcomes of the study were the risk and severity of new stroke in patients with pre-existing AF and gout.

RESULTS

In 2016, we identified 3 844 057 patients admitted to the hospitals in NIS with history of AF, of which 240 875 had history of gout. Patients with AF and gout have higher risk of new stroke (OR 2.07 [1.97-2.19], P < .001), and this risk remains significantly elevated after adjusting for CHADS2VASC score variables, chronic kidney disease, dyslipidemia, obesity, and race (OR 1.10 [1.01-1.11], P = .041). However, presence of gout in patients with AF was not associated with all-cause in-hospital mortality, need for mechanical ventilation, percutaneous gastrostomy tube insertion, or discharge to skilled nursing facility.

CONCLUSION

Subjects with AF and gout compared to AF alone had an increased risk of new stroke, but presence of gout was not associated with stroke severity. There is a potential role of gout as a risk factor or a risk marker for stroke in subjects with AF.

Identification of the urine and serum metabolomics signature of gout

OBJECTIVE

Gout is the most common inflammatory arthritis and the worldwide incidence is increasing. By revealing the metabolic alterations in serum and urine of gout patients, the first aim of our study was to discover novel molecular biomarkers allowing for early diagnosis. We also aimed to investigate the underlying pathogenic pathways.

METHODS

Serum and urine samples from gout patients (n = 30) and age-matched healthy controls (n = 30) were analysed by ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) to screen the differential metabolites and construct a diagnostic model. Next, the model was verified and optimized in the second validation cohort (n = 100). The pathways were illustrated to understand the underlying pathogenesis of gout.

RESULTS

In general, serum metabolomics demonstrated a clearer distinction than urine metabolomics. In the discovery cohort, 40 differential serum metabolites were identified that could distinguish gout patients from healthy controls. Among them, eight serum metabolites were verified in the validation cohort. Through regression analysis, the final model consisted of three serum metabolites-pyroglutamic acid, 2-methylbutyryl carnitine and Phe-Phe-that presented optimal diagnostic power. The three proposed metabolites produced an area under the curve of 0.956 (95% CI 0.911, 1.000). Additionally, the proposed metabolic pathways were primarily involved in purine metabolism, branched-chain amino acids (BCAAs) metabolism, the tricarboxylic acid cycle, synthesis and degradation of ketone bodies, bile secretion and arachidonic acid metabolism.

CONCLUSION

The metabolomics signatures could serve as an efficient tool for early diagnosis and provide novel insights into the pathogenesis of gout.

Serum metabolic profiling analysis of gout patients based on UPLC-Q-TOF/MS

BACKGROUND

Gout is a common kind of inflammatory arthritis with metabolic disorders. However, the detailed pathogenesis of gout is complex and not fully clear. We investigated the serum metabolic profiling of gout patients by ultra-performance liquid chromatograph quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS).

METHODS

Serum metabolites were extracted from 31 gout patients and 31 healthy controls. Metabolite extracts were analyzed in negative mode by UPLC-Q-TOF/MS for global metabolomics. Principal components analysis (PCA), orthogonal partial least squares-discriminant analysis (OPLS-DA) and hierarchical clustering analysis were performed to detect different compounds between the two groups. Receiver operating characteristic (ROC) curve analysis and pathway analysis of the different metabolites were conducted.

RESULTS

A total of 9192 compounds were detected, of which 138 significantly different compounds were selected, according to the criteria of (Variable importance in projection (VIP) > 3). Hierarchical clustering analysis showed that the relative levels of the differential compounds were different between the 2 groups. Ninety-one reliable metabolites matching the human metabolome database (HMDB) were confirmed. ROC curve results revealed that 4-hydroxytriazolam, urate and bilirubin exerted higher AUC values. Pathway analysis indicated that the significantly different metabolites were mainly involved in primary bile acid biosynthesis, purine metabolism and glycerophospholipid metabolism.

CONCLUSIONS

The serum metabolic profiling of gout patients was significantly different from healthy subjects based on UPLC-Q-TOF/MS. Bilirubin was the potential biomarker. Primary bile acid biosynthesis may be a novel metabolic pathway of gout.

Pegloticase in Combination With Methotrexate in Patients With Uncontrolled Gout: A Multicenter, Open-label Study (MIRROR)

OBJECTIVE

To examine the efficacy and safety of pegloticase in combination with methotrexate (MTX) in patients with uncontrolled gout in an exploratory, open-label clinical trial (ClinicalTrials.gov: NCT03635957) prior to a randomized, controlled trial.

METHODS

A multicenter, open-label efficacy and safety study of pegloticase with MTX co-treatment was conducted in patients with uncontrolled gout. Patients were administered oral MTX (15 mg/week) and folic acid (1 mg/day) 4 weeks prior to and throughout pegloticase treatment. The primary study outcome was the proportion of responders, defined as serum uric acid (sUA) < 6 mg/dL for ≥ 80% of the time during Month 6 (Weeks 20, 22, and 24). All analyses were performed on a modified intent-to-treat population, defined as patients who received ≥ 1 pegloticase infusion.

RESULTS

Seventeen patients were screened and 14 patients (all men, average age 49.3 ± 8.7 years) were enrolled. On Day 1, mean sUA was 9.2 ± 2.5 mg/dL, and 12 of the 14 patients had visible tophi. At the 6-month timepoint, 11/14 (78.6%, 95% CI 49.2-95.3%) met the responder definition, with 3 patients discontinuing after meeting protocol-defined treatment discontinuation rules (preinfusion sUA values > 6 mg/dL at 2 consecutive scheduled visits). All patients tolerated MTX. No new safety concerns were identified.

CONCLUSION

In this study, an increased proportion of patients maintained therapeutic response at 6 months when treated concomitantly with MTX and pegloticase as compared to the previously reported 42% using pegloticase alone. These results support the need for a randomized study of MTX or placebo with pegloticase to validate these open-label findings.

A cross-sectional study of 502 patients found a diffuse hyperechoic kidney medulla pattern in patients with severe gout

We have previously shown that ultrasonography can detect hyperechogenic crystal deposits in the kidney medulla of patients with gout. In this cross-sectional study we investigated the frequency and clinical correlates of hyperechogenic kidney medulla in 502 consecutive primary consultants for gout (ACR/EULAR criteria) at the Vien Gut medical center in Ho Chi Minh City, Vietnam. None of these patients received urate-lowering drugs. Kidney medulla echogenicity on B-mode ultrasonography was compared to that of the kidney cortex. Overall, 36% patients showed a hyperechoic pattern of Malpighi pyramids. On univariate analysis, the pattern was significantly associated with age, estimated gout duration, steroid-dependency, clinical tophi, urate arthropathy, double contour thickness at the scanned joints, coronary heart disease, arterial hypertension, hyperuricemia, proteinuria, leukocyturia, and decreased estimated glomerular filtration rate. On multivariable analysis, the hyperechoic pattern was associated with estimated disease duration, clinical tophi, urate arthropathy, double contour thickness and decreased estimated glomerular filtration rate. No hyperechoic pattern was observed in 515 consecutive consultants without gout. Thus, hyperechoic kidney medulla was frequently demonstrated in Vietnamese patients with tophaceous gout and associated with features of tubulointerstitial nephritis. This finding revives the hypothesis of microcrystalline nephropathy of gout, predominantly seen in untreated gouty patients, which could be an important target for urate-lowering therapy.

Gout inheritance in an extended Chinese family analyzed by whole-exome sequencing: A case-report

INTRODUCTION

Gout is a worldwide chronic disease generally caused by high serum levels of uric acid. Using whole exome sequencing, we aimed to explore genetic alterations in hereditary gout.

PATIENTS' CONCERNS

There were 9 direct descendants diagnosed with gout in total in this family. The patients concerned about the high incidence and inheritance of gout.

DIAGNOSIS

The youngest propositus was diagnosed as gout in our hospital. Diagnoses of other patients in this family were made on the foundation of history and clinical tests.

INTERVENTIONS

Six direct descendants and 3 healthy spouses in 1 family were recruited in our study. Whole-exome sequencing was conducted in all participants.

OUTCOMES

Whole-exome sequencing and genetic analysis revealed 2 putative rare inherited deleterious variants, which were detected only in direct descendants. Twelve gout and uric acid (UC)-related nucleotide sequence variants previously reported by GWAS were detected among all subjects.

CONCLUSIONS

In the case of this family, the GWAS identified gout and UC-related nucleotide sequence variants may increase the risk of developing gout, but penetrance was not complete. The rare sequence variants in low-density lipoprotein receptor-related protein 1 (LRP1) and oncoprotein induced transcript 3 (OIT3) may have contributed to inheritance of gout within the 5 generations of family members in this study.

Wastewater-based estimation of the prevalence of gout in Australia

Allopurinol, a first-line gout treatment drug in Australia, was assessed as a wastewater-based epidemiology biomarker of gout via quantification of the urinary metabolite, oxypurinol in wastewater. The in-sewer stability of oxypurinol was examined using laboratory-scale sewer reactors. Wastewater from 75 wastewater treatment plants across Australia, covering approximately 52% (12.2 million) of the country's population, was collected on the 2016 census day. Oxypurinol was quantified in the wastewater samples and population-weighted mass loads calculated. Pearson and Spearman rank-order correlations were applied to investigate any link between allopurinol, other selected wastewater biomarkers, and socio-economic indicators. Oxypurinol was shown to be stable in sewer conditions and suitable as a WBE biomarker. Oxypurinol was detected in all wastewater samples. The estimated consumption of allopurinol ranged from 1.9 to 32 g/day/1000 people equating to 4.8 to 80 DDD/day/1000 people. The prevalence of gout across all tested sewer catchments was between 0.5% to 8%, with a median of 2.9% nationally. No significant positive correlation was observed between allopurinol consumption and alcohol consumption, mean age of catchment population, remoteness or higher socioeconomic status. There was a significant positive correlation with selective analgesic drug use. Wastewater analysis can be used to study gout prevalence and can provide additional insights on population level risk factors when triangulated with other biomarkers.

Hyperuricemia is associated with decreased renal function and occurrence of end-stage renal disease in patients with microscopic polyangiitis and granulomatosis with polyangiitis: a retrospective study

Current evidence suggests that high uric acid levels are associated with accelerated renal damage. However, the clinical impact of serum uric acid level on patients with microscopic polyangiitis (MPA) and granulomatosis with polyangiitis (GPA) is unknown. We aimed to evaluate the impact of hyperuricemia on such patients. A retrospective study was performed to obtain patients' demographic, clinical, and laboratory data from when they were diagnosed with MPA and GPA. Multivariable logistic regression and Cox hazard model analyses were performed to evaluate factors associated with hyperuricemia at diagnosis and predictive factors of end-stage renal disease (ESRD) development. Among 156 patients, 35 (22.4%) had hyperuricemia at baseline. Hyperuricemic patients had renal manifestation and impaired renal function more frequently than non-hyperuricemic patients. Logistic regression analysis revealed that serum creatinine was significantly associated with hyperuricemia at diagnosis [odds ratio 1.995; 95% confidence interval (CI), 1.503-2.648; P < 0.001]. Cox hazard model analysis revealed that body mass index and serum creatinine were significantly associated with ESRD when all variables were included, but hyperuricemia was independently associated with ESRD [hazard ratio (HR), 3.799; 95% CI 1.719-8.222; P < 0.001) when serum creatinine was excluded. Additionally, in a subgroup analysis of patients with decreased glomerular filtration rates (GFRs), serum uric acid was the sole predictor of ESRD (HR, 1.243; 95% CI 1.048-1.475; P = 0.013). Hyperuricemia is associated with renal damage and ESRD occurrence in MPA and GPA patients. Serum uric acid level is associated with ESRD occurrence in patients with decreased GFRs.

A Retrospective Cohort Study of the Effect of Gout on Mortality Among Patients with a History of Kidney Transplantation

Background

Kidney transplantation is associated with increased prevalence of gout. However, evidence of the effect of gout on long-term kidney transplantation outcomes is mixed. This study examined mortality risk among patients with a history of kidney transplantation with vs. without gout.

Material/Methods

A retrospective study was conducted using Medicare Fee-for-Service administrative claims of patients with a history of kidney transplantation. Cox proportional hazards models determined the effect of gout on all-cause mortality, controlling for confounders, including comorbid mortality risk, via the Charlson Comorbidity Index. Because the relationships between gout and components of the Charlson Comorbidity Index are also debated, 3 different model assumptions were used: 1) gout shares a common cause with these comorbidities, 2) gout is upstream of these comorbidities, 3) the effect of gout on mortality is modified by these comorbidities.

Results

Gout increased the risk of all-cause mortality in the unadjusted model (hazard ratio: 1.44, 95% CI 1.27–1.63) and after adjustment for demographics and transplant vintage (hazard ratio: 1.16, 95% CI 1.02–1.32). Gout was not a significant risk after adjustment for baseline Charlson Comorbidity Index (hazard ratio: 1.03, 95% CI 0.90–1.17). Gout was associated with greater mortality among patients without baseline comorbidities (Charlson Comorbidity Index=0; hazard ratio: 3.48, 95% CI 1.27–9.57) in the stratified model.

Conclusions

Among patients with a history of kidney transplantation, gout did not have an independent effect on all-cause mortality. However, gout was a predictor of mortality among patients with no comorbidities, suggesting that gout is an early warning sign of poor health in kidney transplantation patients.

Prevalence of Gout in the Surviving United States Solid Organ Transplantation Population

PURPOSE

Although incidence and survival are frequent topics within the solid organ transplantation (SOT) literature, the size of the surviving SOT population is not well known. Existing studies of gout in patients with SOT have focused on the incident SOT population. This analysis was performed to characterize the prevalent SOT population and the prevalence of gout within it.

METHODS

This study includes the 2017 United States (US) population size of recipients of kidney, heart, liver, and lung transplants that was estimated by combining primary transplant recipient cohort sizes (1988-2017) with previously published survival rates for each annual cohort's time since transplantation (0-29 years). Gout among prevalent patients with SOT was assessed using Medicare and commercial claims.

RESULTS

A total of 637,231 US patients received a primary kidney (393,953), liver (142,186), heart (66,637), or lung (34,455) transplant between 1988 and 2017. An estimated 356,000 (55.8%) recipients were alive in 2017 (233,000 kidney; 78,700 liver; 29,300 heart; 14,700 lung). Gout was identified in 11% of prevalent patients with SOT in 2016. Higher rates of gout were seen in recipients of kidney (13.1%) and heart (12.7%) compared to recipients of liver (6.7%) and lung (5.6%) (P < .0001 in both datasets). Active diagnosed gout prevalence in the US population without a SOT history was 1.1% in 2016.

CONCLUSIONS

Hundreds of thousands of US patients are living with a transplanted organ today and these numbers are likely to increase. In patients with SOT, gout is a frequent comorbidity of which physicians should be aware. This study suggests a markedly higher rate of gout among transplant recipients compared to the general US population.

Association between palliative care and end-of-Life care for patients with hematological malignancies: A population-based study

To date, few studies have examined the end-of-life (EOL) care for patients with hematological malignancies (HMs). We evaluated the effects of palliative care on the quality of EOL care and health care costs for adult patients with HMs in the final month of life.We conducted a population-based study and analyzed data from Taiwan's Longitudinal Health Insurance Database, which contains claims information for patient medical records, health care costs, and insurance system exit dates (our proxy for death) between 2000 and 2011.A total of 724 adult patients who died of HMs were investigated. Of these patients, 43 (5.9%) had received only inpatient palliative care (i-Pal group), and 19 (2.6%) received home palliative care (h-Pal group). The mean health care costs during the final month of life were not significantly different between the non-Pal and Pal groups (p=0.315) and between the non-Pal, i-Pal, and h-Pal groups (p=0.293) either. By the multivariate regression model, the i-Pal group had lower risks of chemotherapy, ICU admission, and receipt of CPR, but higher risks of at least two hospitalizations and dying in hospital after adjustments. The h-Pal group had the similar trends as the i-Pal group but lower risk of dying in hospital after adjustments.Patients with HMs who had received palliative care could benefit from less aggressive EOL cancer care in the final month of life. However, 8.6% patients with HMs received palliative care. The related factors of more hospitalizations and dying in hospital warrant further investigation.

Gout and the risk of advanced chronic kidney disease in the UK health system: a national cohort study

OBJECTIVE

Evaluate the association between gout and risk of advanced chronic kidney disease (CKD).

DESIGN

Retrospective matched cohort study.

SETTING

UK Clinical Practice Research Datalink.

PARTICIPANTS

The analysis included data for 68 897 patients with gout and 554 964 matched patients without gout. Patients were aged ≥18 years, registered at UK practices, had ≥12 months of clinical data and had data linked with Hospital Episode Statistics. Patients were excluded for history of advanced CKD, juvenile gout, cancer, HIV, tumour lysis syndrome, Lesch-Nyhan syndrome or familial Mediterranean fever.

PRIMARY AND SECONDARY OUTCOME MEASURES

Advanced CKD was defined as first occurrence of: (1) dialysis, kidney transplant, diagnosis of end-stage kidney disease (ESKD) or stage 5 CKD (diagnostic codes in Read system or International Classification of Diseases, Tenth Revision); (2) estimated glomerular filtration rate (eGFR) <10 mL/min/1.73 m²; (3) doubling of serum creatinine from baseline and (4) death associated with CKD.

RESULTS

Advanced CKD incidence was higher for patients with gout (8.54 per 1000 patient-years; 95% CI 8.26 to 8.83) versus without gout (4.08; 95% CI 4.00 to 4.16). Gout was associated with higher advanced CKD risk in both unadjusted analysis (HR, 2.00; 95% CI 1.92 to 2.07) and after adjustment (HR, 1.29; 95% CI 1.23 to 1.35). Association was strongest for ESKD (HR, 2.13; 95% CI 1.73 to 2.61) and was present for eGFR <10 mL/min/1.73 m² (HR, 1.45; 95% CI 1.30 to 1.61) and serum creatinine doubling (HR, 1.13; 95% CI 1.08 to 1.19) but not CKD-associated death (HR, 1.14; 95% CI 0.99 to 1.31). Association of gout with advanced CKD was replicated in propensity-score matched analysis (HR, 1.23; 95% CI 1.17 to 1.29) and analysis limited to patients with incident gout (HR, 1.28; 95% CI 1.22 to 1.35).

CONCLUSIONS

Gout is associated with elevated risk of CKD progression. Future studies should investigate whether controlling gout is protective and reduces CKD risk.

Urate-lowering treatment and risk of total joint replacement in patients with gout

Objectives

To examine whether gout is an independent risk factor for total joint replacement (TJR) and whether urate-lowering treatment (ULT) reduces this risk.

Methods

Using the Taiwan National Health Insurance database and the UK Clinical Practice Research Datalink, 74 560 Taiwan patients and 34 505 UK patients with incident gout were identified and age and sex matched to people without gout. Cox proportional hazards models and condition logistic regression were used to examine the risk of TJR in gout patients and the association between cumulative defined daily dose (cDDD) of ULT and TJR.

Results

The prevalence rates of TJR in the patients at the time of diagnosis of gout and in people without gout were 1.16% vs 0.82% in Taiwan and 2.61% vs 1.76% in the UK. After a gout diagnosis, the incidence of TJR was higher in the patients with gout compared with those without (3.23 vs 1.91 cases/1000 person-years in Taiwan and 6.87 vs 4.61 cases/1000 person-years in the UK), with adjusted HRs of 1.56 (95% CI 1.45, 1.68) in Taiwan and 1.14 (1.05, 1.22) in the UK. Compared with patients with gout with <28 cDDD ULT, the adjusted ORs for TJR were 0.89 (95% CI 0.77, 1.03) for 28-90 cDDD, 1.03 (0.85, 1.24) for 90-180 cDDD and 1.12 (0.94, 1.34) for >180 cDDD ULT in Taiwan. In the UK, the respective ORs were 1.09 (0.83, 1.42), 0.93 (0.68, 1.27) and 1.08 (0.94, 1.24).

Conclusion

This population-based study provides evidence from two nation populations that gout confers significant TJR risk, which was not reduced by current ULT.

The Role of a “Treat-to-Target” Approach in the Long-Term Renal Outcomes of Patients with Gout

Background: Although gout is accompanied by the substantial burden of kidney disease, there are limited data to assess renal function as a therapeutic target. This study evaluated the importance of implementing a “treat-to-target” approach in relation to renal outcomes. Methods: Patients with gout who underwent continuous urate-lowering therapy (ULT) for at least 12 months were included. The effect of ULT on renal function was investigated by means of a sequential comparison of the estimated glomerular filtration rate (eGFR). Results: Improvement in renal function was only demonstrated in subjects in whom the serum urate target of <6 mg/dL was achieved (76.40 ± 18.81 mL/min/1.73 m2 vs. 80.30 ± 20.41 mL/min/1.73 m2, p < 0.001). A significant difference in the mean change in eGFR with respect to serum urate target achievement was shown in individuals with chronic kidney disease stage 3 (−0.35 ± 3.87 mL/min/1.73 m2 vs. 5.33 ± 11.64 mL/min/1.73 m2, p = 0.019). Multivariable analysis predicted that patients ≥65 years old had a decreased likelihood of improvement (OR 0.31, 95% CI 0.13–0.75, p = 0.009). Conclusions: The “treat-to-target” approach in the long-term management of gout is associated with better renal outcomes, with a greater impact on those with impaired renal function.

Comparison of medical outcomes and health care costs at the end of life between dialysis patients with and without cancer: a national population-based study

BACKGROUND

Palliative care has improved the quality of end-of-life (EOL) care and lowered the health care cost of cancer, and these benefits should be extended to patients with other serious illnesses including end-stage kidney disease. We evaluated the quality of EOL care, survival probabilities, and health care costs for dialysis patients in their last month of life.

METHODS

We conducted a population-based study and analyzed data from Taiwan's Longitudinal Health Insurance Database, which contains claims information of patient medical records, health care costs, and insurance system exit dates (our proxy for death between 2006 and 2011).

RESULTS

Data of 1177 adult patients who died of chronic hemodialysis or peritoneal dialysis were investigated. The mean age of these patients was 69.7 ± 11.9 years, and 585 (49.7%) were women. Some patients with dialysis received cardiopulmonary resuscitation (66.9%), died in a hospital (65.0%), or were admitted to an intensive care unit (51.0%) in the last month of life. We further classified these patients into two groups, namely dialysis with cancer (DC) (n = 149) and dialysis without cancer (D) (n = 1028). Only 19 dialysis patients received palliative care, and the proportion of patients receiving palliative care was higher in the DC group than in the D group (11.4% vs. 0.2%). The mean health care costs per person during the final month of life was similar between the DC and D groups (USD 2755 ± 259 vs. USD 2827 ± 88). Multivariate logistic regression showed that the DC group had lower odds of receiving cardiopulmonary resuscitation (CPR) (OR: 0.39, CI = 0.26-0.56, p < 0.001) procedures, higher odds of longer hospital stays than the third quartile (> 25 days) (OR: 1.52, CI = 1.01-2.29, p = 0.0046), and higher odds of being hospitalized more than once (OR: 2.26, CI = 1.42-3.59, p = 0.001) than the D group in the last month of life after adjustments.

CONCLUSIONS

DC patients received hospice care more frequently, received CPR less frequently, and had similar health care costs. DC patients also had a higher risk of a hospital stay that lasted more than 25 days and more than one hospitalization compared with D patients in the final month of life.

Gout Severity in Recipients of Kidney Transplant

PURPOSE

This retrospective analysis of medical chart data was performed to compare severity and treatment of gout in patients with or without a history of kidney transplantation (KT).

METHODS

Via an online survey, a panel of board-certified US nephrologists (N = 104) provided the following deidentified chart data for their 3 most recent patients with gout: age, sex, serum uric acid, numbers of swollen or tender joints, visible tophi, gout flare events (prior 12 months), gout drug treatment history, and KT history. The presence of "severe, uncontrolled gout" was defined as: serum uric acid ≥ 7.0 mg/dL, ≥1 tophi and ≥2 flares in the last 12 months, and history of xanthine oxidase inhibitor treatment.

RESULTS

Twenty-five out of 312 (8.0%) gout patients had a history of KT. Univariate analysis found that patients with gout and history of kidney transplants had: greater prevalence of severe uncontrolled gout (27% vs 8%, P = .007) and tophi (36% vs 17%, P = .030), and higher rates of failure or physician perceived contraindication to allopurinol (44% vs 23%, P = .028).

CONCLUSION

This study provides preliminary evidence that gout in patients with history of KT is more severe and poses greater challenges to pharmacologic management. Although gout has been linked to worse outcomes among kidney recipients in the literature, there are presently no publications on gout severity among patients with KT in comparison to other patients with gout. Further investigation of disease severity and appropriate, effective treatment options in recipients of kidney transplant with a diagnosis of gout, especially prior to the transplant, is warranted.

Study of epidemiological aspects of hyperuricemia in Poland

BACKGROUND

The results of the latest epidemiological studies show that the problem of hyperuricemia affects many millions of people. The main purpose of the study was to assess the knowledge of physicians with regard to the epidemiology and treatment of hyperuricemia in Poland.

METHODS

CAPI (computer assisted personal interview) interviews were conducted using short questionnaires among primary health care physicians, cardiologists and diabetologists. The entire questionnaire included 11 questions. Questions were asked to physicians at 5 different periods in time. The number of physicians surveyed, depended on the time period, and ranged from 8663 to 9980.

RESULTS

Only every 1 in 7 physicians (14%) considered that hyperuricemia in patients with cardiovascular risk factors begins when the uric acid level is 5 mg/dL, thus in line with the expert recommendations. 72% of respondents asked to indicate the uric acid levels they consider to be indicative of hyperuricemia in patients in the cardiovascular risk group, gave values ranging from 6 to 7 mg/dL, namely the values justified in cases of a patient without such a risk, i.e. in the general population. 86% of doctors surveyed gave values different from that recommended by experts.

CONCLUSIONS

The findings of the questionnaire in this survey suggests that doctors often underestimate the problem of hyperuricemia in patients with a high risk of cardiovascular disease. An important step towards more effective therapy of hyperuricemia in routine clinical practice is to raise the awareness of hyperuricemia and its comorbidities both among doctors and patients and encourage monitoring and treatment.

[Comorbidity in gout and hyperuricemia: prevalence, causes, prospects of urate lowering therapy]

Nowadays, there is increased interest in the connection of gout and asymptomatic hyperuricemia with comorbid conditions such as diabetes mellitus, cardiovascular diseases, hypertension, chronic kidney disease and other. Studies conducted over the past few decades suggest that not only gout, but also asymptomatic hyperuricemia can significantly worsen the prognosis in patients with cardiovascular diseases, as the deposition of urate crystals can be both an immediate cause and a factor in the progression of renal failure. In that way, the timely appointment of urate - lowering therapy and achieving the target serum uric acid level can not only affect joint damage, but also can significantly slow the progression of life - threatening comorbid conditions.

Characterization of patients with chronic refractory gout who do and do not have clinically apparent tophi and their response to pegloticase

OBJECTIVES

To determine the characteristics and response to pegloticase of patients with chronic refractory gout with and without clinically apparent tophi.

METHODS

Results from two randomized controlled trials of pegloticase in patients with chronic refractory gout with clinically apparent tophi or without tophi were used to assess baseline and on-treatment between-group differences.

RESULTS

Patients with tophi were significantly older than those without tophi, had a significantly longer duration of disease, higher numbers of tender and swollen joints, higher Patient Global Assessment scores and Health Assessment Questionnaire-Disability Index scores, and lower Arthritis-Specific Health Index scores. Patients with tophaceous gout also had significantly lower scores for physical functioning, role physical, social functioning, and the physical component summary scores of the Short Form 36 vs patients without tophi. In addition, subjects with clinically apparent tophi had a significantly lower mean estimated glomerular filtration rate. Pegloticase treatment of tophaceous patients caused significant reductions in serum urate, flares, Patient Global Assessment, tender joints, swollen joints, Health Assessment Questionnaire-Disability Index, visual analogue scale pain and Short Form 36 Bodily Pain, whereas patients without tophi had significant improvement in serum urate, flares, Patient Global Assessment, tender joints, and Short Form 36 Bodily Pain, but not swollen joints, Health Assessment Questionnaire-Disability Index functional score or pain visual analogue scale. Treatment with pegloticase had no effect on estimated glomerular filtration rate despite significant lowering of the urinary uric acid: creatinine ratio.

CONCLUSION

Patients with chronic refractory gout and clinically apparent tophi have more severe disease as well as reduced renal function. Both groups experienced significant clinical benefit with pegloticase treatment, although no change in renal function was noted.

U. A, Adeeb F, Fraser AD, Stack AG. Prevalence and treatment of gout among patients with chronic kidney disease in the Irish health system: A national study

Background

Gout is a common inflammatory arthritis associated with adverse clinical outcomes. Under treatment is common in the general population. The aim of this study was to determine the prevalence of gout and its treatment among patients with chronic kidney disease (CKD).

Methods

We conducted a multi-centre cross sectional study of patients (n = 522) who attended specialist nephrology clinics in Ireland. Standardized data collection tool recorded clinical characteristics and medication use at clinic visits and kidney function was assessed with standardised creatinine measurements and Estimated Glomerular Filtration Rate (eGFR). The prevalence of gout and the corresponding use of urate lowering therapies (ULT) were determined. Multivariate logistic regression explored correlates of gout expressed as Odds Ratios (OR) and 95% Confidence Intervals (CI) adjusting for demographic and clinical characteristics.

Results

Overall prevalence of gout was 16.6% and increased significantly from 7.5% in Stage 1–2 CKD to 22.8% in stage 4–5 CKD, P< 0.005. Prevalence increased with age (P < 0.005) and was higher in men than women (19.1% versus 10.3% P< 0.005). Overall, 67.9% of gout patients with CKD were treated with ULT, and the percentage increased with advancing stage of CKD from 55.6% in Stage 1–2 to 77.4% in Stage 4–5, P<0.005. Multivariable modelling identified men (vs women), OR, 1.95 (0.95–4.03), serum albumin, OR 1.09 (1.02–1.16) per 1 g/L lower, poorer kidney function, OR 1.11 (1.01–1.22) per 5 ml/min/1.73m² lower, and rising parathyroid hormone levels, OR 1.38 (1.08–1.77) per 50 pg/ml higher as disease correlates.

Conclusions

Gout is common in CKD and increases with worsening kidney function in the Irish health system. Over two thirds of patients with gout were receiving ULT, increasing to 77% of patients with advanced CKD. Greater awareness of gout in CKD, its treatment and the effectiveness of treatment strategies should be vigorously monitored to improve patient outcomes.

Urinary Uromodulin/Creatinine Ratio as a Potential Clinical Biomarker for Chronic Kidney Disease Patients with Gout: A Pilot Study

OBJECTIVE

Recent studies have reported that reduced excretion of urinary uromodulin is associated with renal tubular function and risks of progressive kidney disease. Gouty nephropathy is usually seen in patients with gout. Patients with chronic gouty nephropathy are characterized by the deposition of monosodium urate crystals primarily involving the collecting ducts in the medulla. We postulated that this correlation may be specific to gout and may serve as a useful biomarker for chronic kidney disease (CKD).

MATERIALS AND METHODS

A total of 114 Taiwanese patients diagnosed with gout (n = 72), CKD (n = 26), or healthy volunteers (n = 16) were prospectively enrolled for this study from the Rheumatology and Nephrology Outpatient Clinics of our institution. We obtained urine and blood samples on patient visits to the outpatient clinics. Demographic data were obtained from medical records.

RESULTS

In patients with gout, the spot urinary uromodulin/creatinine ratio (uUMCR; mg/g) in patients with CKD was significantly lower than that in those without CKD (CKD group: 2.2; non-CKD group: 5.6, p = 0.005). Multivariate analysis revealed that patients with CKD and gout had a lower uUMCR than those with gout alone (p = 0.028). A significant association was not observed in our non-gout cohort.

CONCLUSION

The association of decreased uUMCR with CKD status was identified only in patients with gout in the present study. We believe that uUMCR might serve as an indicator of differential CKD in patients with gout.

Risk of chronic kidney disease in patients with gout and the impact of urate lowering therapy: a population-based cohort study

Background

An association between gout and renal disease is well-recognised but few studies have examined whether gout is a risk factor for subsequent chronic kidney disease (CKD). Additionally, the impact of urate-lowering therapy (ULT) on development of CKD in gout is unclear. The objective of this study was to quantify the risk of CKD stage ≥ 3 in people with gout and the impact of ULT.

Methods

This was a retrospective cohort study using data from the Clinical Practice Research Datalink (CPRD). Patients with incident gout were identified from general practice medical records between 1998 and 2016 and randomly matched 1:1 to patients without a diagnosis of gout based on age, gender, available follow-up time and practice. Primary outcome was development of CKD stage ≥ 3 based on estimated glomerular filtration rate (eGFR) or recorded diagnosis. Absolute rates (ARs) and adjusted hazard ratios (HRs) were calculated using Cox regression models. Risk of developing CKD was assessed among those prescribed ULT within 1 and 3 years of gout diagnosis.

Results

Patients with incident gout (n = 41,446) were matched to patients without gout. Development of CKD stage ≥ 3 was greater in the exposed group than in the unexposed group (AR 28.6 versus 15.8 per 10,000 person-years). Gout was associated with an increased risk of incident CKD (adjusted HR 1.78 95% CI 1.70 to 1.85). Those exposed to ULT had a greater risk of incident CKD, but following adjustment this was attenuated to non-significance in all analyses (except on 3-year analysis of women (adjusted HR 1.31 95% CI 1.09 to 1.59)).

Conclusions

This study has demonstrated gout to be a risk factor for incident CKD stage ≥ 3. Further research examining the mechanisms by which gout may increase risk of CKD and whether optimal use of ULT can reduce the risk or progression of CKD in gout is suggested.

Electronic supplementary material

The online version of this article (10.1186/s13075-018-1746-1) contains supplementary material, which is available to authorized users.

Urinary Metabolomics Study of Patients with Gout Using Gas Chromatography-Mass Spectrometry

Objectives

Gout is a common type of inflammatory arthritis. The aim of this study was to detect urinary metabolic changes in gout patients which may contribute to understanding the pathological mechanism of gout and discovering potential metabolite markers.

Methods

Urine samples from 35 gout patients and 29 healthy volunteers were analyzed by gas chromatography-mass spectrometry (GC-MS). Orthogonal partial least-squares discriminant analysis (OPLS-DA) was performed to screen differential metabolites between two groups, and the variable importance for projection (VIP) values and Student's t-test results were combined to define the significant metabolic changes caused by gout. Further, binary logistic regression analysis was performed to establish a model to distinguish gout patients from healthy people, and receiver operating characteristic (ROC) curve was made to evaluate the potential for diagnosis of gout.

Result

A total of 30 characteristic metabolites were significantly different between gout patients and controls, mainly including amino acids, carbohydrates, organic acids, and their derivatives, associated with perturbations in purine nucleotide synthesis, amino acid metabolism, purine metabolism, lipid metabolism, carbohydrate metabolism, and tricarboxylic acid cycle. Binary logistic regression and ROC curve analysis showed the combination of urate and isoxanthopterin can effectively discriminate the gout patients from controls with the area under the curve (AUC) of 0.879.

Conclusion

Thus, the urinary metabolomics study is an efficient tool for a better understanding of the metabolic changes of gout, which may support the clinical diagnosis and pathological mechanism study of gout.

Managing Gout in the Patient with Renal Impairment

Hyperuricaemia is an independent risk factor for renal function decline. Evidence is emerging that urate-lowering therapy might be beneficial in subjects with renal impairment. We  review the association between renal impairment and gout, some of the related pathogenic processes and the possible impact of gout treatment on the progression of renal impairment. Nevertheless, the management of gout is more complex in the presence of chronic kidney disease. The main aim of gout therapy is to fully dissolve the urate crystals, thus curing the disease. Avoidance of attacks-prophylaxis-and their prompt treatment if they occur, along with accurate information to patients, completes the treatment strategy. This article provides a practical guide to managing gout in older patients and in those with renal impairment. We highlight the shortcomings in our current treatment options and strategies.

Comorbidity in gout at the time of first diagnosis: sex differences that may have implications for dosing of urate lowering therapy

Background

The aim of this study is to examine the occurrence of comorbidities at the time of first diagnosis of gout compared with matched population controls, overall and by sex, as well as to examine the crude and age-standardized prevalence of these comorbidities in men and women with gout at first diagnosis.

Methods

A population-based study used data from Swedish national and regional registers, including 14,113 gout patients aged ≥ 20 years, with a first recorded diagnosis of gout between 1 January 2006 and 31 December 2012, and 65,782 population controls, matched by age, sex and county. Prevalence ratios (95% confidence intervals) comparing gout cases and controls were calculated, overall and by sex. Crude and age-standardized prevalence (95% confidence interval) of all comorbidities in gout patients were calculated, to show differences between sexes, taking also the higher age at diagnosis in women into account.

Results

All examined comorbidities were 1.2–2.5-fold more common in gout patients at diagnosis than in population controls in both sexes. Women with gout were on average 6 years older than men at first gout diagnosis and most comorbidities, including obesity and diuretic use, were or tended to be more frequent in women than in men. When standardizing for age, women had a higher prevalence of thromboembolism (6.6% vs 5.2%) and chronic obstructive pulmonary disease (3.1% vs 2.4%). Men, on the other hand, had a higher prevalence of coronary heart disease (9.4% vs 6.4%), atrial fibrillation (9.0% vs 6.0%), congestive heart failure (7.7% vs 6.6%) and stroke (4.1% vs 3.3%).

Conclusions

The occurrence of most comorbidities was significantly increased at first diagnosis of gout in both sexes. Women were older at diagnosis and had higher occurrence of most comorbidities, including obesity and diuretic use, factors that increase serum urate, and this needs to be taken into account when starting and optimizing urate lowering therapy. These sex differences were attenuated when standardizing for age and the occurrence of cardiovascular diseases was actually higher in men.

Electronic supplementary material

The online version of this article (10.1186/s13075-018-1596-x) contains supplementary material, which is available to authorized users.