Assessing the causal relationships of gut microbial genera with hyperuricemia and gout using two-sample Mendelian randomization

BACKGROUND AND AIMS

The causal relationship between gut microbiota and gout and hyperuricemia (HUA) has not been clarified. The objective of this research was to evaluate the potential causal effects of gut microbiota on HUA and gout using a two-sample Mendelian randomization (MR) approach.

METHODS AND RESULTS

Genetic instruments were selected using summary statistics from genome-wide association studies (GWASs) comprising a substantial number of individuals, including 18,473 participants for gut microbiome, 288,649 for serum urate (SU), and 763,813 for gout. Two-sample MR analyses were performed to determine the possible causal associations of gut microbial genera with the risk of HUA and gout using the inverse-variance weighted (IVW) method, and robustness of the results was confirmed by several sensitivity analyses. A reverse MR analysis was conducted on the bacterial taxa that were identified in forward MR analysis. Based on the results of MR analyses, Escherichia-Shigella (OR = 1.05; 95% CI, 1.01-1.08; P = 0.009) exhibited a positive association with SU levels, while Lachnospiraceae NC2004 group (OR = 0.95; 95% CI, 0.92-0.98; P = 0.001) and Family XIII AD3011 group (OR = 0.94; 95% CI, 0.90-0.99; P = 0.015) were associated with a reduced HUA risk. Moreover, Coprococcus 3 (OR = 1.17, 95% CI: 1.01-1.34, P = 0.031) was causally associated with a higher gout risk. In reverse MR analysis, no causal relationships were identified between these bacterial genera and HUA or gout.

CONCLUSION

This study provides evidence for a causal association between gut microbial genera and HUA or gout, and further investigations of the underlying mechanism are warranted.

Hyperuricaemia-associated all-cause mortality risk effect is increased by non-impaired kidney function - Is renal hyperuricaemia less dangerous?

BACKGROUND

Both hyperuricaemia and chronic kidney disease are known mortality risk factors. This study examined the modifying effect of renal function on hyperuricaemia-associated mortality risk, which is an issue that has not been studied before.

METHODS

Data on levels of serum uric acid (SUA), creatinine, cystatin C and other variables of persons aged 52-76 years were collected. Persons with SUA >410 μmol/L (75th percentile) were classified as clearly hyperuricaemic and persons with eGFR of ≤67 ml/min (25th percentile) as having reduced kidney function.

RESULTS

Reduced kidney function was associated with higher mortality in both SUA groups. When compared to individuals with SUA ≤410 μmol/L and eGFR >67 ml/min the hazard ratio (HR) for all-cause mortality was 1.53 (95 % CI: 1.26-1.84) in clearly hyperuricaemic persons with reduced kidney function, 1.26 (95 % CI: 1.02-1.55) in clearly hyperuricaemic persons with eGFR of >67 ml/min and 1.15 (95 % CI: 0.96-1.39) in persons with SUA ≤410 μmol/L and reduced kidney function. The HR for hyperuricaemia-related premature death was lowest in individuals with reduced eGFR, and it rose strikingly as the eGFR increased above 90 ml/min.

CONCLUSIONS

Reduced kidney function is a risk factor for mortality both in individuals with normal and elevated SUA. The hyperuricaemia-associated mortality risk is remarkably higher in individuals with normal kidney function than in individuals with reduced kidney function. Presumably overproduction of uric acid (metabolic hyperuricaemia) is a separate and more deleterious entity than hyperuricaemia resulting from reduced renal excretion of uric acid (renal hyperuricaemia).

Nontraditional Risk Factors for Progression Through Chronic Kidney Disease Risk Categories: The Coronary Artery Risk Development in Young Adults Study

BACKGROUND

There may be nontraditional pathways of chronic kidney disease (CKD) progression that are complementary to classical pathways. Therefore, we aimed to examine nontraditional risk factors for incident CKD and its progression.

METHODS

We used the generally healthy population (n = 4382) starting at age 27-41 years in the Coronary Artery Risk Development in Young Adults (CARDIA) cohort, which is an observational longitudinal study. Nontraditional risk factors included forced vital capacity, inflammation, serum urate, and serum carotenoids. CKD risk category was classified using the estimated glomerular filtration rate (eGFR) and urinary albumin-to-creatinine ratio (UACR) measured in 1995-1996 and repeated every 5 years for 20 years: No CKD, low risk, moderate risk, high risk, and very high risk.

RESULTS

At baseline, 84.8% had no CKD (eGFR ≥60 mL/min/1.73 m2 and UACR <10 mg/g), 10.3% were in the low risk (eGFR ≥60 and UACR 10-29), and 4.9% had CKD (eGFR <60 and/or UACR ≥ 30). Nontraditional risk factors were significantly associated with the progression of CKD to higher categories. Hazard ratios per standard deviation of the predictor for incident CKD and its progression from the No CKD and low and moderate risk into CKD were inverse for forced vital capacity and serum carotenoids and positive for serum urate, GlycA, and C-reactive protein, the first 3 even after adjustment for conventional risk factors.

CONCLUSION

Several nontraditional markers were significantly associated with an increased risk of progression to higher CKD categories in generally healthy young to middle-aged adults.

Relationship between rs4349859 and rs116488202 polymorphisms close to MHC-I region and serum urate levels in patients with gout

BACKGROUND

Gout is the most common inflammatory rheumatic disease and elevated levels of serum urate (SU) are the main cause for its development. Major histocompatibility complex class 1 (MHC-1) plays an important role in the development of multiple inflammatory diseases; however, there is little evidence of its involvement in gout. The present study focused on evaluating the association of the rs4349859 and rs116488202 single nucleotide polymorphisms (SNPs) close to the MHC-1 region in patients with gout.

METHODS AND RESULTS

One hundred and seventy-six individuals of Mexican origin were included, of which 81 were patients with primary gout and 95 were healthy controls. The rs4349859 and rs116488202 SNPs were genotyped using TaqMan probes by allelic discrimination by real-time PCR. Serum concentrations of biochemical parameters were measured with enzymatic methods. Descriptive statistics were applied and P-values < 0.05 were considered significant. It was observed that the rs4349859 and rs116488202 SNPs showed significant association with the risk of gout (OR = 146, 95%CI = 44.8-480.2, P < 0.01; OR = 2885, 95%CI = 265-31398, P < 0.01, respectively). Our results also showed significantly higher serum SU levels in gout patients with respect to controls (P < 0.01) in the carriers of the GA genotype compared with the GG genotype of the rs4349859 variant, and in the carriers of the CT genotype compared with the CC genotype of the rs116488202 variant.

CONCLUSION

The study revealed that rs4349859 and rs116488202 SNPs close to MHC-I region confers strong susceptibility to gout in Mexican population, and the heterozygous genotypes of both were associated with higher levels of SU.

Fluctuation and change of serum urate levels and flares in gout: results from the NOR-Gout study

A gout attack may evolve after a purine-rich diet or alcohol and after starting urate-lowering therapy (ULT). The relationships between fluctuation and change in serum urate (SU) with the occurrence of flares were investigated in this study. In the prospective NOR-Gout study, gout patients with increased SU and a recent flare were treated to target with ULT over 1 year, with follow-up at year 2 with SU and flare as outcomes. SU and flares were assessed at both monthly and 3-monthly intervals until target SU was reached. Fluctuation over periods and changes in SU between two time points were assessed and compared in patients with and without flares. At year 1, 186 patients completed follow-up (88.2%) and 173 (82.0%) at year 2. Mean age (SD) at baseline was 56.4 (13.7) years, disease duration was 7.8 (7.6) years, and 95.3% were men. The first-year SU fluctuation and change were related to flare occurrence during year 1 (both p < 0.05). High fluctuation with an absolute sum of all SU changes during the first 9 months was related to flares over 3-month periods (all p < 0.05), and high fluctuation during the first 3 months was related to flares in months 3-6 (p = 0.04). Monthly and high SU changes or again reaching higher SU levels > 360 µmol/l were not related to flares. Fluctuation and change in SU were related to flare occurrence during the first year of ULT, while changes between visits and reaching SU levels > 360 µmol/L were not related to flares. Key Points • Urate-lowering therapy seeks to achieve a treatment target and prevent gout flares, and changes in serum urate are related to gout flares. • Fluctuation and changes in serum urate were associated with gout flares, suggesting that fluctuation in serum urate is unfavourable during gout treatment. • During urate-lowering therapy in gout in clinical practice, fluctuation of serum urate, for example, due to lack of adherence, should be observed and avoided.

Serum urate and heart failure: a bidirectional Mendelian randomization study

AIMS

Observational studies indicate that serum urate level is associated with heart failure (HF). However, whether this association is causal remains controversial, due to confounding factors and reverse causality. We aim to evaluate the causal relationship of genetically predicted serum urate level with HF.

METHODS AND RESULTS

A bidirectional Mendelian randomization (MR) study was performed. Instrumental variables were obtained from the largest genome-wide association studies of serum urate (457 690 individuals) to date. We obtained summary statistics of HF from HERMES consortium (47 309 cases; 930 014 controls), the FinnGen study (13 087 cases; 195 091 controls), and the UK Biobank study (1088 cases; 360 106 controls). Inverse-variance-weighted method was applied to obtain MR estimates and other statistical methods were conducted in the sensitivity analyses. The reverse MR analysis was performed to evaluate the effect of HF on serum urate levels. Genetically determined serum urate level was associated with HF [odds ratio (OR), 1.07; 95% confidence interval (CI), 1.03-1.10; P = 8.6×10-5]. The main results kept robust in the most sensitivity analyses. The association pattern remained for the HF in FinnGen (OR, 1.10; 95% CI, 1.03-1.19; P = 0.008) and the combined results of three data sources (OR, 1.08; 95% CI, 1.04-1.13; P < 0.001). No consistent evidence was found for the causal effect of HF on serum urate levels.

CONCLUSION

We provide consistent evidence for the causal effect of genetically predicted serum urate level on HF, but not the reverse effect of HF. Urate-lowering therapy may be of cardiovascular benefit in the prevention of HF.

Genetically predicted physical activity is associated with lower serum urate concentrations

BACKGROUND

Physical activity (PA) is considered to play an important role in the reduced gout risk. However, the epidemiology results are inconsistent and causality remains unclear.

OBJECTIVE

To investigate the causal relationship of PA with serum urate concentrations and gout risk by a bidirectional Mendelian randomization (MR) approach.

METHOD

Two genome-wide association studies (GWASs) from UK Biobank were used to identify instrumental variables for self-reported moderate-to-vigorous PA (including 377,234 European individuals), accelerometer-measured 'average acceleration' PA (including 91,084 European individuals) and accelerometer-measured overall PA (including 91,105 European individuals). The summary data for serum urate (including 110,347 European individuals) and gout (including 2,115 cases and 67,259 controls) were derived from GWAS of Global Urate Genetics Consortium. Moreover, reverse direction Mendelian randomization study was conducted. The inverse-variance weighted, weighted median, Mendelian randomization Egger regression, simple mode and weighted mode and Mendelian Randomization Pleiotropy RESidual Sum and Outlier were methods we performed.

RESULT

Genetic predisposition to accelerometer-measured 'average acceleration' PA [beta = -0.038; 95% confidence interval (CI) = -0.060,-0.015; P = 0.001] and accelerometer-measured overall PA (beta = -0.339; 95% CI = -0.522,-0.156; P = 2.8E-4) were significantly associated with decreased serum urate concentrations. Besides, there was no evidence supporting the causal association between PA and gout risk. In the reverse direction analysis, genetic predisposition to both urate and gout were not associated with PA being investigated.

CONCLUSIONS

In MR study, we found that PA may reduce serum urate concentrations but not the risk of gout. Moreover, serum urate concentrations and gout were not associated with PA.

Change in serum urate level with urate-lowering therapy initiation associates in the immediate term with patient-reported outcomes in people with gout

OBJECTIVE

To examine the associations of changes in serum urate (SU) with health-related quality of life (HRQOL) in gout.

METHODS

We used the first 6-months of data from four interventional trials and one observational, open-label study of urate-lowering therapy (ULT) use. HRQOL were assessed at baseline and every 3-months, and SU was measured monthly. Primary outcome measures were Short-form 36 physical and mental component summary scores, Health Assessment Questionnaire Disability Index (HAQ-DI), Sheehan Disability Scale (SDS), Patient Global Assessment, and pain scores in the last week. Linear mixed models for each outcome were adjusted as appropriate for current SU, change in urate in the last month, number of flare-affected days in the last month, baseline BMI, age, comorbidities, sex, ethnicity, trial/study and treatment combination, and tophi status (fixed effects); subject, and the trial/study month were random effects.

RESULTS

Higher current SU correlated with reduced physical and mental HRQOL, and increased SDS and pain but not with HAQ-DI score. In the first 6-months of new/escalating ULT use, absolute change in SU levels associated with poorer outcomes on the HAQ-DI scale (β (95% CI) = 0.013 (0.007-0.019)) and poorer outcomes on SDS, SF-36 MCS, patient global and pain scales. Reduction of SU associated with poorer outcomes in all six measures.

CONCLUSION

High SU levels were associated with poorer HRQOL, pain and Sheehan disability score. Recent SU level fluctuations are associated with poorer outcomes, primarily driven by a reduction in SU. Clinical emphasis on slow rather than fast SU reduction and the routine use of effective, anti-inflammatory medications at ULT initiation/escalation may avoid short-term poor outcomes.

Sex-specific effect of serum urate levels on coronary heart disease and myocardial infarction prevention: A Mendelian randomization study

BACKGROUND AND AIMS

Observational studies have examined serum urate levels in relation to coronary heart disease (CHD) and myocardial infarction (MI). Whether these associations are causal remains controversial, due to confounding factors and reverse causality. We aim to investigate the causality of these associations using Mendelian randomization method.

METHODS AND RESULTS

Instrumental variables were obtained from the largest genome-wide association studies of serum urate (457,690 individuals) to date. Summary statistics were from CARDIoGRAMplusC4D consortium (60,801 CHD cases; 43,676 MI cases), FinnGen (21,012 CHD cases; 12,801 MI cases), UK Biobank (10,157 CHD cases; 7018 MI cases), and Biobank Japan (29,319 CHD cases). Inverse-variance weighted method was applied as the main results. Other statistical methods and reverse MR analysis were conducted in the supplementary analyses. Elevated genetically determined serum urate levels were associated with increased risks of CHD and MI. The association pattern remained for the datasets in FinnGen, the combined results of three independent data sources (CHD: odds ratio (OR), 1.10; 95%CI, 1.06-1.15; p = 4.2 × 10^-6; MI: OR, 1.12; 95%CI, 1.07-1.18; p = 2.7 × 10^-6), and East Asian population. Interestingly, sex-specific subgroup analyses revealed that these associations kept in men only, but not among women in individuals of European ancestry. No consistent evidence was found for the causal effect of CHD or MI on serum urate levels.

CONCLUSION

We provide consistent evidence for the causal effect of genetically predicted serum urate levels on CHD and MI, but not the reverse effect. Urate-lowering therapy may be of cardiovascular benefit in the prevention of CHD and MI, especially for men.

Serum urate as a proposed surrogate outcome measure in gout trials: From the OMERACT working group

Serum urate (SU) is the most common primary efficacy outcome in trials of urate-lowering therapies for gout. Despite this, it is not formally considered a validated surrogate outcome. In this paper we will outline the definitions of biomarkers and surrogate outcome measures, respectively as well as the available frameworks and challenges in the assessment of the validity of serum urate as a surrogate in gout (i.e. a reasonable replacement for gout symptoms).

Evaluate the effects of serum urate level on bone mineral density: a genome-wide gene-environment interaction analysis in UK Biobank cohort

INTRODUCTION

Serum urate is associated with BMD and may be a protective factor. However, the exact association and mechanism are still unclear. We performed a genome-wide gene-environmental interaction study (GWGEIS) to explore the interaction effects between gene and urate on BMD, using data from the UK Biobank cohort.

METHODS

A total of 4575 participants for femur total BMD, 4561 participants for L1-L4 BMD, and 237799 participants for heel BMD were included in the present study. Linear regression models were used to test for associations between urate and BMD (femur total BMD, L1-L4 BMD, heel BMD) by R software. GWGEIS was conducted by PLINK 2.0 using a generalize linear model, adjusted for age, sex, weight, smoking behavior, drinking behavior, physical activity and 10 principle components for population structure.

RESULTS

Results showed that urate was positively associated with femur total BMD, L1-L4 BMD and heel BMD and similar findings were observed in both the male and female subgroups. GWGEIS identified 261 genome-wide significant (P < 5.00 × 10^-8) SNP × urate interaction effects for femur total BMD (rs8192585 in NOTCH4, rs116080577 in PBX1, rs9409991 in COL5A1), 17 genome-wide significant SNP × urate interaction effects for heel BMD (rs145344540 in PDE11A and rs78485379 in DKK2), 17 suggestive genome-wide SNP × urate interaction effects (P < 1.00 × 10^-5) for L1-L4 BMD (rs10977015 in PTPRD). We also detected genome-wide significant and suggestive SNP × urate interaction effects for BMD in both the male and female subgroups.

CONCLUSIONS

This study reported several novel candidate genes, and strengthen the evidence of the interactive effects between gene and urate on the variations of BMD.

DNAm-based signatures of accelerated aging and mortality in blood are associated with low renal function

BACKGROUND

The difference between an individual's chronological and DNA methylation predicted age (DNAmAge), termed DNAmAge acceleration (DNAmAA), can capture life-long environmental exposures and age-related physiological changes reflected in methylation status. Several studies have linked DNAmAA to morbidity and mortality, yet its relationship with kidney function has not been assessed. We evaluated the associations between seven DNAm aging and lifespan predictors (as well as GrimAge components) and five kidney traits (estimated glomerular filtration rate [eGFR], urine albumin-to-creatinine ratio [uACR], serum urate, microalbuminuria and chronic kidney disease [CKD]) in up to 9688 European, African American and Hispanic/Latino individuals from seven population-based studies.

RESULTS

We identified 23 significant associations in our large trans-ethnic meta-analysis (p < 1.43E-03 and consistent direction of effect across studies). Age acceleration measured by the Extrinsic and PhenoAge estimators, as well as Zhang's 10-CpG epigenetic mortality risk score (MRS), were associated with all parameters of poor kidney health (lower eGFR, prevalent CKD, higher uACR, microalbuminuria and higher serum urate). Six of these associations were independently observed in European and African American populations. MRS in particular was consistently associated with eGFR (β =  - 0.12, 95% CI = [- 0.16, - 0.08] change in log-transformed eGFR per unit increase in MRS, p = 4.39E-08), prevalent CKD (odds ratio (OR) = 1.78 [1.47, 2.16], p = 2.71E-09) and higher serum urate levels (β = 0.12 [0.07, 0.16], p = 2.08E-06). The "first-generation" clocks (Hannum, Horvath) and GrimAge showed different patterns of association with the kidney traits. Three of the DNAm-estimated components of GrimAge, namely adrenomedullin, plasminogen-activation inhibition 1 and pack years, were positively associated with higher uACR, serum urate and microalbuminuria.

CONCLUSION

DNAmAge acceleration and DNAm mortality predictors estimated in whole blood were associated with multiple kidney traits, including eGFR and CKD, in this multi-ethnic study. Epigenetic biomarkers which reflect the systemic effects of age-related mechanisms such as immunosenescence, inflammaging and oxidative stress may have important mechanistic or prognostic roles in kidney disease. Our study highlights new findings linking kidney disease to biological aging, and opportunities warranting future investigation into DNA methylation biomarkers for prognostic or risk stratification in kidney disease.

Association of urate deposition shown by ultrasound and frequent gout attacks

BACKGROUND

There are few data demonstrating the association between urate burden assessed by ultrasound (US) and gout flares. The aim of this study was to determine the association of urate deposition shown by US and frequent gout attacks.

MATERIALS AND METHODS

Patients with gout were divided into two groups according to the frequency of gout attacks in the previous 12 months: frequent (>2 attacks) and infrequent (0-2 attacks). Urate deposition in the hands, knees, and feet was assessed by US.

RESULTS

Overall, 106 patients were enrolled in this study, of whom 32 (30.1%) had had frequent gout attacks (>2 attacks) in the previous 12 months (the average number of gout attacks was 4.7, range 3-12). Those with frequent gout attacks had significantly longer gout duration, a higher serum urate level, and more urate deposition shown by US than those with infrequent gout attacks (P < 0.05). In both univariate and logistic regression analyses, frequent gout attacks were correlated with gout duration, serum urate level, and urate deposition as shown by US (P < 0.05).

CONCLUSION

These findings indicate that urate deposition shown by US is independently associated with frequent gout attacks. Special attention should be given to the prevention of flares in patients with an initially high urate burden as assessed by US.

Gout

The treat to target strategy looks attractive for management of gout because it removes the causal mechanism inducing formation, growth, and aggregation of urate crystals. Further reduction of serum urate (sUA) levels below the threshold may dissolve crystals more rapidly. It is generally agreed that sUA less than 6 mg/dL is acceptable as a therapeutic and long-term preventive target, with <5 mg/dL for the most severe cases. The challenges that this approach in gout is facing include whether proposed targets are the best for desired outcomes, whether they fit patient-related outcomes, and whether they adequately balance effectiveness and safety.

Repeated measurements of serum urate and mortality: a prospective cohort study of 152,358 individuals over 8 years of follow-up

BACKGROUND

Longitudinal evidence on change of serum urate level with mortality risk is limited as prior studies have a measurement of serum urate at a single time point. Further, the combined effect of serum urate and systemic inflammation on mortality is unknown.

METHODS

We conducted a prospective cohort study of 152,358 participants (122,045 men and 30,313 women) with repeated measurements of serum urate in 2006, 2008, 2010, and 2012 (107,751 participants had all four measurements of serum urate). We used the Cox proportional hazard model to examine the association between cumulative average and changes in serum urate with mortality. The combined effect of serum urate and systemic inflammation was determined by testing the interaction of serum urate and high-sensitive C-reactive protein (hs-CRP) in relation to mortality risk.

RESULTS

During a median follow-up of 8.7 (interquartile range 6.3-9.2) years, we identified 7564 all-cause deaths, 1763 CVD deaths, 1706 cancer deaths, and 1572 other deaths. We observed U-shaped relationships of cumulative average serum urate with all-cause mortality, cardiovascular mortality, and other mortalities. Compared with participants with stable serum urate, those with greater increases in serum urate had a 1.7-fold elevated mortality (hazard ratio (HR) = 1.66, 95% confidence interval (CI) = 1.49-1.84), and those with decreased serum urate had a 2-fold elevated mortality risk (HR = 2.14, 95% CI 1.93-2.37). Participants with both hyperuricemia and hs-CRP had 1.6 times higher mortality, compared with those with low serum urate and hs-CRP levels (HR = 1.56, 95% CI 1.37-1.76).

CONCLUSIONS

We observed a U-shaped relationship of long-term cumulative average serum urate with all-cause mortality, cardiovascular mortality, and other mortalities. Compared with participants with relatively stable serum urate levels, a greater increase or decrease in serum urate was associated with elevated mortality. Participants with both hyperuricemia and high systemic inflammation had the greatest mortality risk compared with those with low serum urate and low hs-CRP levels.

Association between serum level of urate and subclinical atherosclerosis: results from the SCAPIS Pilot

BACKGROUND

Hyperuricemia is closely associated with cardiovascular disease (CVD). However, it has not been definitively established whether this association is independent of traditional cardiovascular risk factors (CVRFs) and whether it is gender-dependent. The aim of this study was to investigate in a population-based cohort (age range, 50-64 years) stratified by sex the association between the serum urate (SU) concentration and subclinical atherosclerosis, as reflected in the coronary artery calcification (CAC) score, common carotid intima-media thickness (CIMT), and carotid plaque score.

METHODS

The study involved participants in the Swedish CArdioPulmonary bioImage Study (SCAPIS) Pilot cohort (N = 1040; 48.8% males). This pilot cohort is part of the large population-based SCAPIS with 30,000 participants in the age range of 50-64 years, aimed at improving risk prediction for CVD. Subjects with a self-reported previous history of CVD (N = 68) or gout (N = 3) were excluded. The CAC score was assessed with the Agatston method using computed tomography. CIMT and carotid plaques were quantified by ultrasound. The associations between the SU quartiles and different levels of CAC, CIMT, and carotid plaques were assessed by multivariable logistic regression.

RESULTS

Age, BMI, education level, smoking, physical activity, hs-CRP, hypertension, and dyslipidemia showed no differences between males and females, while CAC (score > 0) and diabetes were both twice as common in men than in women (58% vs 26% and 8% vs 4%, respectively). Higher SU quartiles were in both sexes associated with BMI, hs-CRP, and the prevalence of hypertension, and in women, they were also associated with the prevalence of dyslipidemia. The three upper quartiles of SU (>308μmol/L) were linked to higher CAC scores in men, when adjusting for CVRFs, but not in women. CIMT and carotid plaques showed no correlation to SU in either sex.

CONCLUSIONS

Higher levels of SU are associated with the presence of CAC in men but not in women, whereas SU is not associated with CIMT or carotid plaques in either men or women. This implies that the biological effects of SU differ in men and women or that SU has varying effects on different vascular beds or during the different stages of the atherosclerotic process.

Different associations between serum urate and diabetic complications in men and postmenopausal women

AIMS

The objective of this study was to investigate the different associations of the serum urate (SUA) level with cardiovascular and cerebrovascular diseases (CVD), diabetic kidney disease (DKD) and diabetic retinopathy (DR) in Chinese adults.

METHODS

We analyzed 4767 participants out of 4813 adults with diabetes enrolled from seven communities in a cross-sectional survey. Participants underwent several medical examinations, including the measurement of anthropometric factors, blood pressure, SUA, glucose, lipid profiles, urine albumin/creatinine ratio (ACR) and fundus photographs.

RESULTS

Compared with the first SUA tertile, the third tertile increased the prevalence of CVD by 22% (OR 1.22; 95% CI 1.01, 1.46) (P for trend <0.05) and increased the prevalence of DKD by 59% (OR 1.59; 95% CI 1.28, 1.97) for KDOQI definition. Compared with the first tertile, the OR (95% CI) of the number of diabetic complications, ranging from 0 to 2, associated with SUA level in ordinal logistic regression was 1.75 (1.44, 2.12) for the third tertile (P for trend <0.01). These associations were all fully adjusted. No association was found between the prevalence of DR and the SUA level.

CONCLUSIONS

A higher SUA level was associated with an increased prevalence of CVD and DKD and a variety of diabetic complications, other than DR, in men and postmenopausal women with T2DM. However, the causation remains to be demonstrated.

Epistatic interaction between PKD2 and ABCG2 influences the pathogenesis of hyperuricemia and gout

BACKGROUND

Genetic background affects serum urate concentration and gout risk, especially regarding these variants in the urate-transporter gene ABCG2. However, the role of epistasis between PKD2 and ABCG2 on the pathogenesis of gout is poorly understood. Here we assess this epistatic interaction in the progression from elevated serum urate to gout.

RESULTS

We identified two epistatic interaction pairs (rs2728121: rs1481012 and rs2728121: rs2231137) were associated with urate levels in 4914 Chinese individuals (Pint = 0.018 and 0.004, respectively). Using subgroup analysis for gender and BMI, we found the degree of associations was varied by gender and BMI. The SNP pair rs2728121:rs1481012 influenced urate levels in females and overweight subjects (Pint = 0.006 and 0.022, respectively), but rs2728121:rs2231137 did in males, overweight and normal-weight subjects (Pint = 0.017, 0.047 and 0.013, respectively). Consistent results were also observed in associations between these epistatic interactions with hyperuricemia. Next, the SNP pair rs2728121:rs2231137 was identified to influence the development of gout from both hyperuricemia and healthy (Pint = 0.035 and 0.001, respectively), especially in males (Pint = 0.030 and 0.001, respectively). Furthermore, we demonstrated that interacting regions were enriched by regulatory elements. Finally, we observed a strong gene co-expression pattern between PKD2 and ABCG2 (r = 0.743, P = 5.83E-06).

CONCLUSION

Our findings indicate epistasis between PKD2 and ABCG2 influence serum urate concentrations, hyperuricemia and gout risk, thus providing insight into the pathogenesis of gout.

Adherence and Outcomes with Urate-Lowering Therapy: A Site-Randomized Trial

PURPOSE

The purpose of this study was to test a pharmacist-led intervention to improve gout treatment adherence and outcomes.

METHODS

We conducted a site-randomized trial (n=1463 patients) comparing a 1-year, pharmacist-led intervention to usual care in patients with gout initiating allopurinol. The intervention was delivered primarily through automated telephone technology. Co-primary outcomes were the proportion of patients adherent (proportion of days covered ≥0.8) and achieving a serum urate <6.0 mg/dl at 1 year. Outcomes were reassessed at year 2.

RESULTS

Patients who underwent intervention were more likely than patients of usual care to be adherent (50% vs 37%; odds ratio [OR] 1.68; 95% confidence interval [CI] 1.30, 2.17) and reach serum urate goal (30% vs 15%; OR 2.37; 95% CI 1.83, 3.05). In the second year (1 year after the intervention ended), differences were attenuated, remaining significant for urate goal but not for adherence. The intervention was associated with a 6%-16% lower gout flare rate during year 2, but the differences did not reach statistical significance.

CONCLUSIONS

A pharmacist-led intervention incorporating automated telephone technology improved adherence and serum urate goal in patients with gout initiating allopurinol. Although this light-touch, low-tech intervention was efficacious, additional efforts are needed to enhance patient engagement in gout management and ultimately to improve outcomes.

Efficacy and safety during extended treatment of lesinurad in combination with febuxostat in patients with tophaceous gout: CRYSTAL extension study

Background

In gout, long-term urate-lowering therapy (ULT) promotes dissolution of tissue urate crystal deposits. However, no studies using combined xanthine oxidase inhibition and uricosuric ULT have focused on clinical outcomes or adverse events (AEs) beyond 12 months of therapy. Our objective in the present study was to examine efficacy and long-term safety in patients with tophaceous gout receiving febuxostat plus lesinurad as combination therapy.

Methods

Patients receiving combined lesinurad and febuxostat in the 12-month core CRYSTAL study continued at the same doses in the extension study (“200CONT”, “400CONT”), whereas those receiving only febuxostat 80 mg were randomized to lesinurad 200 or 400 mg with febuxostat (“200CROSS”, “400CROSS”). The primary endpoint was the proportion of patients experiencing complete resolution (CR) of at least one target tophus by extension month (EM) 12. The key secondary endpoint was mean rate of gout flares requiring treatment from the end of EM 2 to the end of EM 12. Secondary endpoints included reduction in the sum of areas for all target tophi. Safety assessments included AEs and laboratory data for the entire extension study (median length of lesinurad exposure, 800 days).

Results

Of 235 patients completing the core study, 196 (83.4%) enrolled in the extension: 200CONT (n = 64), 200CROSS (n = 33), 400CONT (n = 65), and 400CROSS (n = 34). At EM 12, 59.6%, 43.5%, 66.7%, and 50.0% of patients, respectively, had CR of at least one target tophus. The sum of areas for all target tophi was reduced by 76.4%, 58.1%, 77.5%, and 62.8%, respectively. The adjusted mean (SE) rates of gout flares requiring treatment from the end of EM 2 to the end of EM 12 were 0.6 (0.19), 1.3 (0.48), 0.2 (0.08), and 1.9 (0.93), respectively. Target sUA < 5.0 mg/dl was achieved by 77.1%, 79.2%, 88.5%, and 71.4% of patients, respectively. Exposure-adjusted incidence rates of treatment-emergent adverse events (TEAEs) and renal-related TEAEs in the core study were not increased with prolonged lesinurad exposure in the extension study.

Conclusions

Patients receiving lesinurad plus febuxostat therapy for 2 years continued to be at sUA target. Patients exhibited a progressive increase in CR of at least one target tophus, progressive reduction in tophus size, and reduction of gout flares requiring treatment over the second year, with AEs consistent with those observed in the core study.

Trial registration

ClinicalTrials.gov, NCT01510769. Registered on 13 January 2012.

Electronic supplementary material

The online version of this article (10.1186/s13075-018-1788-4) contains supplementary material, which is available to authorized users.

Tophus resolution in patients with chronic refractory gout who have persistent urate-lowering responses to pegloticase

BACKGROUND

Pegloticase is a recombinant mammalian uricase conjugated to polyethylene glycol approved in the United States for treatment of chronic refractory gout. It can profoundly decrease serum urate to < 1 mg/dl. In patients receiving pegloticase who did not generate high-titer antidrug antibodies (responders), the serum urate remained low for the duration of therapy, 6 months in the phase III clinical trials plus the open-label extension. The objective of this study was to assess the velocity of tophus resolution in subjects treated with pegloticase.

METHODS

Data from two randomized controlled trials of pegloticase in chronic refractory gout were analyzed. Tophi were assessed by computer-assisted measurements of standardized digital photographs. Subjects were designated as responders and nonresponders based on maintenance of serum urate < 6 mg/dl at months 3 and 6 of treatment. The projected time of complete resolution of all tophi was determined by linear regression analysis.

RESULTS

The mean total tophus area at baseline was 585.8 mm² for responders, 661.5 mm² for nonresponders, and 674.4 mm² for placebo-treated patients. Complete resolution at 6 months of at least one tophus was achieved by 69.6% of 23 responders, 27.9% of 43 nonresponders, and 14.3% of 21 patients who received placebo. Complete resolution of all photographed tophi was achieved by 34.8% of biochemical responders, 11.6% of nonresponders, and 0% of placebo-treated patients. The mean velocity of resolution of all tophi was 60.1 mm²/month in responders with a mean projected time of complete resolution of 9.9 months (4.6-32.6 months). There was a significant inverse correlation between serum urate AUC and tophus resolution velocity (r = - 0.40, P = 0.0002), although considerable heterogeneity in the velocity of resolution was noted. The only patient characteristic that correlated with the velocity of tophus resolution was the baseline tophus area.

CONCLUSIONS

Pegloticase treatment caused a rapid resolution of tophi in responders that correlated with the serum urate lowering associated with this therapy.

Serum urate as surrogate endpoint for flares in people with gout: A systematic review and meta-regression analysis

OBJECTIVES

The primary efficacy outcome in trials of urate lowering therapy (ULT) for gout is serum urate (SU). The aim of this study was to examine the strength of the relationship between SU and patient-important outcomes to determine whether SU is an adequate surrogate endpoint for clinical trials.

METHODS

Multiple databases through October 2017 were searched. Randomized controlled trials comparing any ULT in people with gout with any control or placebo, ≥three months duration were included. Open label extension (OLE) trial data were included in secondary analyses. Standardized data elements were extracted independently by two reviewers.

RESULTS

Ten RCTs and 3 OLE studies were identified. From the RCTs (maximum duration 24 months) meta-regression did not reveal an association between the relative risk of a gout flare and the difference in proportions of individuals with SU < 6mg/dL (P = 0.47; R2 = 8%). In a post hoc analysis, the ratio of the time in months at which the proportion of individuals having a flare was reported/time in months at which the proportion of individuals with SU < 6mg/dL was reported was calculated and studies where the ratio was <2 were excluded. Using the remaining 6 studies there was an association between proportion of individuals achieving SU < 6mg/dL and gout flares (over patient years). Duration of ULT was inversely associated with the proportion of patients experiencing a flare. Study duration and variability in reporting of outcomes limited the analysis. Observational studies supported the trend of fewer flares in those with lower SU.

CONCLUSIONS

Based on aggregate clinical trial-level data an association between SU and gout flare could not be confirmed. However, based on observational ecological study design data-including longer duration extension studies-SU < 6mg/dL was associated with reduced gout flares.

Predicting Response or Non-response to Urate-Lowering Therapy in Patients with Gout

PURPOSE OF REVIEW

To review the extent of treatment success or failure with the xanthine oxidoreductase inhibitors allopurinol and febuxostat and indicate how the dosage of urate-lowering therapy (ULT) may be modified to increase the response in the majority of patients with gout.

RECENT FINDINGS

Gout flares are associated with serum concentrations of urate above 0.42 mmol/L (7 mg/dL). Achieving and maintaining serum urate below 0.36 mmol/L is considered an effective response to ULT. On an intention to treat basis, clinical trials indicate that allopurinol at daily doses of 100 to 300 mg decreases serum urate adequately in only about 40% of gout patients while febuxostat 80 mg daily reduces serum urate adequately in approximately 70% of gout patients. Higher doses of ULT may be required in patients receiving concomitant diuretics. The addition of a uricosuric agent to allopurinol and febuxostat therapy significantly increases the proportion of patients achieving adequate lowering of serum urate. Finally, carriers of a genetic variant of the transporter, ABCG2 (BCRP), have a decreased response to allopurinol. Careful examination of medication adherence, titration of doses, and the addition of uricosuric agents increase the percentage of patients responding to allopurinol and febuxostat.

Untangling the complex relationships between incident gout risk, serum urate, and its comorbidities

BACKGROUND

Many gout comorbidities (e.g., hypertension) are correlated with serum urate. In this investigation, we identified risk factors (e.g., systolic blood pressure [SBP]), that (1) are associated with incident gout, (2) have effects on gout risk that cannot be fully explained by correlated differences in serum urate, and (3) may modulate the relationship between gout and serum urate.

METHODS

Using data from the Atherosclerosis Risk in Communities (ARIC) study, we estimated the unadjusted associations between gout and risk factors by calculating ORs and using chi-square tests. The adjusted associations were analyzed using logistic regression by sequentially adding (1) one risk factor at a time or (2) all risk factors, to a baseline model that includes serum urate only. Stepwise selection was used to select main effects. Two-way interactions of variables from the main effects model were also analyzed.

RESULTS

Average gout incidence was 2.7 per 1000 people per year. Serum urate was highly associated with incident gout, with odd ratios of 3.16 [95% CI 2.11, 4.76] and 25.9 [95% CI 17.2, 38.4] for moderately high (6-8 mg/dl) and high serum urate (> 8 mg/dl), relative to normal serum urate (< 6 mg/dl), respectively. Ethnicity and SBP were independently and additively associated with gout after accounting for serum urate levels. No significant interactions were found between serum urate and ethnicity or SBP.

CONCLUSIONS

Ethnicity and hypertension are predictive of gout risk, and the associations cannot be fully explained by serum urate. For serum urate levels near the crystallization threshold (6-8 mg/dl) African Americans and people with hypertension are at two to three times greater risk for developing gout. The gout risk for this group appears to increase before the onset of severe hyperuricemia.

Impact of diuretics on the urate lowering therapy in patients with gout: analysis of an inception cohort

Background

Diuretics have been associated with impaired response and refractoriness in gout, but whether this effect is still present with new urate-lowering drugs (ULD) and treat-to-target strategies is unknown. The aim of the present study was to assess the impact of the diuretics on the response to ULD in patients with gout. 

Methods

This was a retrospective analysis of an inception cohort. Participants were classified according to the type of ULD prescribed. We analysed the maximal dose of ULD (primary outcome variable), serum urate (SU) reduction, and the achievement of different SU targets (6 mg/dL, 5 mg/dL, and 4 mg/dL), according to the type of ULD prescribed and use of diuretics (loop and/or thiazide). We adjusted for confounders using multiple linear regression analysis.

Results

We included 245 patients: 208 treated with allopurinol (66 on diuretics, 31.7%), 35 with febuxostat (19 on diuretics, 57.6%), and 2 with benzbromarone. Significantly fewer participants in the allopurinol plus diuretics subgroup achieved SU levels of less than 5 mg/dL, but we found no other significant differences in SU targets associated with diuretics. Regarding the maximum ULD dose, a simple linear regression suggested an inverse relationship with diuretics (beta = − 0.125, p = 0.073), but this did not hold in the multivariable analysis (beta = − 0.47, p = 0.833). There was no association with febuxostat (beta = − 0.116, p = 0.514).

Conclusion

Diuretics do not appear to have a significant impact on managing gout.

Electronic supplementary material

The online version of this article (10.1186/s13075-018-1559-2) contains supplementary material, which is available to authorized users.

The effect of kidney function on the urate lowering effect and safety of increasing allopurinol above doses based on creatinine clearance: a post hoc analysis of a randomized controlled trial

BACKGROUND

The use of allopurinol in people with chronic kidney disease (CKD) remains one of the most controversial areas in gout management. The aim of this study was to determine the effect of baseline kidney function on safety and efficacy of allopurinol dose escalation to achieve serum urate (SU) <6 mg/dl.

METHODS

We undertook a post hoc analysis of a 24-month allopurinol dose escalation treat-to-target SU randomized controlled trial, in which 183 people with gout were randomized to continue current dose allopurinol for 12 months and then enter the dose escalation phase or to begin allopurinol dose escalation immediately. Allopurinol was increased monthly until SU was <6 mg/dl. The effect of baseline kidney function on urate lowering and adverse effects was investigated.

RESULTS

Irrespective of randomization, there was no difference in the percentage of those with creatinine clearance (CrCL) <30 ml/min who achieved SU <6 mg/dl at the final visit compared to those with CrCL ≥30 to <60 ml/min and those with CrCL ≥60 ml/min, with percentages of 64.3% vs. 76.4% vs. 75.0%, respectively (p = 0.65). The mean allopurinol dose at month 24 was significantly lower in those with CrCL <30 ml/min as compared to those with CrCL ≥30 to <60 ml/min or CrCL ≥60 ml/min (mean (SD) 250 (43), 365 (22), and 460 (19) mg/day, respectively (p < 0.001)). Adverse events were similar among groups.

CONCLUSIONS

Allopurinol is effective at lowering urate even though and accepting that there were small numbers of participants with CrCL <30 ml/min, these data indicate that allopurinol dose escalation to target SU is safe in people with severe CKD. The dose required to achieve target urate is higher in those with better kidney function.

TRIAL REGISTRATION

Australian and New Zealand Clinical trials Registry, ACTRN12611000845932 . Registered on 10 August 2011.

Quality of care in gout: a clinical audit on treating to the target with urate lowering therapy in real-world gout patients

The current paper aimed to describe the quality of care for gout patients by showing the clinical outcomes achieved in two patient cohorts in which differing targeted urate lowering therapy (ULT) treatment approaches were employed, both aiming to reach the European League Against Rheumatism recommended serum urate (sUA) targets. A retrospective medical chart review study was conducted. Data from the medical records of gout patients from two clinical centers in The Netherlands, both applying targeted ULT treatments (albeit using different approaches), were reviewed. Patients in cohort A were given a combination of xanthine oxidase inhibitors with uricosurics if treatment with allopurinol monotherapy failed to reach sUA target levels, whereas patients in cohort B were treated with sequential monotherapy. Data on patient characteristics and clinical outcomes were collected. A total of 177 patient dossiers were included: 99 from cohort A and 78 from cohort B. The great majority (n = 146, 82.5%) of the patients in both cohorts had a current sUA level <360 µmol/L. In addition, more than half (n = 104, 58.8%) of the patients met the stringent sUA target level of <300 µmol/L. The largest reductions in mean sUA levels were observed for patients who were treated with combination therapy. This clinical audit of two cohorts of gout patients provides initial—yet promising—results regarding the proportion of real-world gout patients in whom recommended that sUA target levels can be achieved, and demonstrates the added value that a targeted treatment approach may have in reaching these goals.

Fructose malabsorption in people with and without gout: A case-control study

BACKGROUND

Higher fructose intake has been associated with hyperuricaemia and gout. Some individuals malabsorb fructose in the small intestine. The aims of this study were to determine the rate of fructose malabsorption and the effects of gout and fructose malabsorption on serum urate in people with and without gout.

METHODS

A total of 100 people with gout (cases) were age and gender matched with one control without gout. After a low fructose diet, fructose malabsorption was measured using a hydrogen and methane breath test with a 35g fructose load. In a subgroup of 35 cases and 35 controls, serum urate response to the fructose load over 240 minutes was measured.

RESULTS

There was no significant difference in the rate of fructose malabsorption between cases and controls (48% vs. 52%; p = 0.67). Cases had a significantly lower mean (SEM) serum urate cumulative incremental concentration from baseline-240 minutes (iAUC_0-240) compared to controls 0.97 (0.56) vs. 4.78 (0.55); p < 0.001. C_max was significantly lower in cases compared to controls [0.38 (0.003) vs. 0.40 (0.003); p < 0.001]. 95% of cases were receiving allopurinol. There was no significant difference between iAUC_0-240 or C_max for malabsorbers compared to normal absorbers irrespective of case-control status. The mean (SEM) increase in serum urate between baseline and 30 minutes was 0.04 (0.004)mmol/l in the controls compared to 0.009 (0.002) in the cases (p < 0.001).

CONCLUSION

The rates of fructose malabsorption are similar in people with and without gout. Allopurinol inhibits the increase in serum urate induced by a fructose load suggesting that people with gout receiving allopurinol may not need to restrict dietary intake of fructose.

Gout: will the "King of Diseases" be the first rheumatic disease to be cured?

Gout is the most common inflammatory arthritis in adults in the Western world. Characterized by hyperuricemia and the effects of acute and chronic inflammation in joints and bursa, gout leads to an agonizing, chronically painful arthritis. Arthritis can also be accompanied by urate nephropathy and subcutaneous urate deposits (tophi). Exciting new developments in the last decade have brought back the focus on this interesting, crystal-induced chronic inflammatory condition. New insights include the role of NALP3 inflammasome-induced inflammation in acute gout, the characterization of diagnostic signs on ultrasound and dual-energy computed tomography imaging modalities, the recognition of target serum urate less than 6 mg/day as the goal for urate-lowering therapies, and evidence-based treatment guidelines. A better understanding of disease mechanisms has enabled drug discovery - three new urate-lowering drugs have been approved in the last decade, with several more in the pipeline. We now recognize the important role that environment and genetics play in the causation of gout. A focus on the cardiac, renal, and metabolic comorbidities of gout will help translational research and discovery over the next decade.

The effects of urate lowering therapy on inflammation, endothelial function, and blood pressure (SURPHER) study design and rationale

BACKGROUND

The association between hyperuricemia and hypertension is controversial. Animal models, epidemiological data, and small clinical trials have favored a causative role for hyperuricemia in hypertension but more studies are necessary to elucidate putative mechanisms, population susceptibility, and potential for urate-lowering therapies (ULT) to decrease blood pressure (BP).

PURPOSE

To describe the background and design of the Serum Urate Reduction to Prevent Hypertension (SURPHER) study.

METHODS

SURPHER is a single center, double-blinded, crossover trial in which participants are randomly assigned to allopurinol (300mg) or placebo. Enrollment focused on adults 18-40years old with baseline systolic blood pressure≥120 and <160mmHg or diastolic blood pressure≥80 and <100mmHg, and serum urate ≥5.0mg/dL or ≥4.0mg/dL for men or women, respectively. SURPHER recruitment targets participants without chronic kidney disease (estimated glomerular filtration rate>60mL/min/1.73m2), and without prior diagnosis of gout or use of ULT to treat gout. The primary outcome is change from baseline in blood pressure assessed by 24hour ambulatory blood pressure monitoring and mechanistic outcomes include changes in endothelial function as measured by flow-mediated dilation, as well as C-reactive protein levels.

RESULTS

Since June 16, 2014 until present, SURPHER is recruiting participants in the city of Birmingham, Alabama.

LIMITATIONS

The study aims to enroll otherwise healthy young adults for a pharmacological intervention study with multiple study-related procedures. Challenges related to recruitment are anticipated and multiple strategies for increasing recruitment and retention are planned if necessary.

Rationale and design of the randomized evaluation of an Ambulatory Care Pharmacist-Led Intervention to Optimize Urate Lowering Pathways (RAmP-UP) Study

BACKGROUND

Despite the availability of effective therapies, most gout patients achieve suboptimal treatment outcomes. Current best practices suggest gradual dose-escalation of urate lowering therapy and serial serum urate (sUA) measurement to achieve sUA<6.0mg/dl. However, this strategy is not routinely used. Here we present the study design rationale and development for a pharmacist-led intervention to promote sUA goal attainment.

METHODS

To overcome barriers in achieving optimal outcomes, we planned and implemented the Randomized Evaluation of an Ambulatory Care Pharmacist-Led Intervention to Optimize Urate Lowering Pathways (RAmP-UP) study. This is a large pragmatic cluster-randomized trial designed to assess a highly automated, pharmacist-led intervention to optimize allopurinol treatment in gout. Ambulatory clinics (n=101) from a large health system were randomized to deliver either the pharmacist-led intervention or usual care to gout patients over the age of 18years newly initiating allopurinol. All participants received educational materials and could opt-out of the study. For intervention sites, pharmacists conducted outreach primarily via an automated telephone interactive voice recognition system. The outreach, guided by a gout care algorithm developed for this study, systematically promoted adherence assessment, facilitated sUA testing, provided education, and adjusted allopurinol dosing. The primary study outcomes are achievement of sUA<6.0mg/dl and treatment adherence determined after one year. With follow-up ongoing, study results will be reported subsequently.

CONCLUSION

Ambulatory care pharmacists and automated calling technology represent potentially important, underutilized resources for improving health outcomes for gout patients.

A world of hurt: failure to achieve treatment goals in patients with gout requires a paradigm shift

BACKGROUND

Gout continues to be underdiagnosed and poorly managed despite the potential for cure. US and European management guidelines recommend treating to target serum urate (sUA) levels of <6 mg/dL (or <5 mg/dL to durably improve severe symptoms), with use of regular sUA monitoring, but studies suggest relatively poor adherence to these recommendations. This study investigates the real-world state of gout management in the United States by describing the characteristics of a large patient population treated in primary care and rheumatology settings.

METHODS

A retrospective chart audit, conducted among 124 primary care physicians and 125 rheumatologists, included 1245 patients with gout. Physicians completed structured case report forms capturing 12 months of sUA laboratory values, flare counts, comorbidities, types and doses of treatment, treatment duration, diagnosis date, physician specialty and socio-demographic factors. Focusing on the xanthine oxidase inhibitors (n = 858), descriptive statistics and multivariate models characterized relationships between patient characteristics, disease control, and treatment.

RESULTS

Only 83 (11%) patients achieved disease control, defined as a 12-month average sUA ≤6 mg/dL, no flares, and no tophi. Patients with greatest disease severity (defined as sUA >6 mg/dL, ≥2 flares per year, and tophi) were more likely to have kidney disease and other comorbidities. In a multivariate model, predictors of more severe gout were rheumatologist (vs primary care) management, febuxostat (vs allopurinol) use and presence of comorbid conditions.

CONCLUSION

Our findings confirm the inadequacy of gout management in the real-world setting. Regular monitoring, including sUA measurement as recommended in guidelines, is important to assess gout control. Our analyses also demonstrate that patients with more severe gout are more likely to have comorbid conditions, be treated by a specialist and use newer therapies.

Significance of the initiation time of urate-lowering therapy in gout patients: A retrospective research

OBJECTIVE

To evaluate the efficacy and safety of the initiation time of urate-lowering treatments (ULT) in gout patients.

METHOD

We retrospectively reviewed patients who were diagnosed with gout and were treated with ULT for at least 3 years. They were divided into two groups: group 1: 123 patients initiating ULT during an acute attack of gout; group 2: 457 patients prescribed ULT after an acute attack. Both demographic and clinical characteristics associated with gout were analyzed.

RESULTS

Comparing patients in group 1 versus group 2: the former exhibited a shorter duration of gout (6.3±2.1 vs. 8.9±3.3 years). At the baseline, there was no significant difference in mean serum urate (SU; 7.8±1.4mg/dL vs. 7.9±1.9mg/dL, respectively). SU target levels (<6.0mg/dL) were achieved by 66.7 and 65.6% of the patients, respectively. The duration from initiation of ULT until the SU target was attained was lower in group 1 than in group 2. During the first 12 weeks, patients on ULT in group 1 had higher attack rates than those in group 2. The incidence of chronic kidney disease increased in percentage in group 1 was lower than in group 2.

CONCLUSIONS

Our survey revealed that in patients experiencing acute gout, initiation of ULT decreased the time required to reach the target SU and the incidence of CKD, but the attack rate was greater in the first 12 weeks.