Gender-specific risk factors for incident gout: a prospective cohort study

Long-term exposure to ambient PM2.5 and its components associated with hyperuricemia: Evidence from a rural cohort study

BACKGROUND

Current research lacks the association of PM2.5 and its components exposure with hyperuricemia (HUA). This study aimed to explore the association of PM2.5 and its components with HUA and to identify harmful components as well as susceptible populations.

METHODS

A total of 22,765 participants were derived from the Henan rural cohort. PM2.5 and its components data were obtained from the Tracking Air Pollution (TAP) dataset in China. Generalized linear models (GLM) were utilized to evaluate the association between PM2.5 and its components with HUA. Restricted cubic splines were employed to explore the dose-response relationship. Additionally, the weighted quantile sum (WQS) method was used to assess the joint effect of PM2.5 components and their relative contribution to HUA.

RESULTS

After adjusting for confounders, the odds ratios (OR) and 95 % confidence interval (CI) for per standard deviation (SD) increase in PM2.5, black carbon (BC), nitrate (NO3-), sulfate (SO42-), ammonium (NH4+), and organic matter (OM) were 1.81 (1.43, 2.30), 1.69 (1.38, 2.07), 1.70 (1.39, 2.08), 1.73 (1.40, 2.14), 1.67 (1.38, 2.04), and 1.58 (1.30, 1.92), respectively. Joint exposure to the five major chemical components also showed a positive association with the risk of HUA [1.09 (1.04, 1.15)], with NO3- contributing most significantly to the combined effect of the pollutant mixture. Additionally, exposure to PM2.5 and its components showed a nonlinear dose-response relationship with HUA (P nonlinear < 0.05). Stratified analysis indicated that men may be more susceptible to the effects of environmental PM2.5 and BC.

CONCLUSION

PM2.5 and its components increased the risk of HUA, with NO3- being the primary contributor, and men were more susceptible to the effects of PM2.5 and BC. The findings suggests that reducing PM2.5 levels could bring significant public health benefits.

Elevated blood pressure and hyperuricemia risk: a retrospective cohort study from Wuhu, China

Although the relationship between hypertension and hyperuricemia is widely recognized, there is still a relative lack of research on prehypertensive individuals and the individual associations of systolic and diastolic blood pressure with the risk of hyperuricemia. From 2011 to 2016, we conducted a study on 53,323 individuals at Wuhu City Hospital in China. Based on initial blood pressure readings, participants were categorized into normal, prehypertension, or hypertension groups. We used Cox regression to analyze the associations with baseline factors. In subgroup analyses, systolic and diastolic pressures were treated as continuous variables, and their relationship with the risk of hyperuricemia was examined using restricted cubic spline analysis. The risk increased in the prehypertension and hypertension groups compared to the normal blood pressure group, with hazard ratios of 1.192 and 1.350, respectively. For each unit increase in blood pressure, the risk of hyperuricemia rose by 0.8% (systolic) and 0.9% (diastolic), especially when blood pressure levels exceeded 115/78 mmHg. Additionally, we observed that factors such as gender, alcohol consumption habits, obesity, and dyslipidemia might further influence this association. These findings emphasize the importance of early risk assessment and intervention in these patient populations in clinical practice.

Hyperuricaemia Prevalence Rates According to Their Physiochemical and Epidemiological Diagnostic Criteria and Their Associations with Cardio-Renal-Metabolic Factors: SIMETAP-HU Study

Background: Scientific societies disagree on serum uric acid (SUA) thresholds for the diagnosis of hyperuricaemia (HU) according to epidemiological or physiochemical criteria (SUA ≥ 7.0 mg/dL for men and ≥6.0 mg/dL for women [HU-7/6]; SUA ≥ 7.0 mg/dL for both genders [HU-7/7], respectively). HU is not included among the diagnostic criteria for metabolic syndrome or cardiovascular-renal-metabolic syndrome (CKM), although it promotes atherosclerosis and is associated with renal and cardiometabolic diseases. Both issues are of utmost importance and need to be clarified, hence the present study aims to assess the prevalence rates of HU and their associations with CKM factors. Methods: A cross-sectional observational study was conducted on a random population-based sample of 6489 adults. Bivariate and multivariate analyses were performed on the most well-known renal and cardiometabolic variables of the populations with and without HU-7/7 and HU-7/6. Results: The adjusted prevalence rates for HU-7/6 were 13.4% in adult population (18.4% in men; 9.6% in women) and 10.2% (18.4% in men; 3.8% in women) for HU-7/7. The main factors associated independently with HU for both genders were low estimated glomerular filtration rate, hypertension, hypertriglyceridaemia, and alcoholism, regardless of the criteria chosen, as well as albuminuria in women and central obesity in men. Conclusions: The prevalence rates of HU increase linearly with age for both genders. The associations of CKM factors with HU diagnosed according to physiochemical criterion are more similar between men and women than those using epidemiological criteria.

The role of body mass index on the association between the energy-adjusted dietary inflammatory index and hyperuricemia: a mediation analysis based on NHANES (2007-2016)

BACKGROUND

The Energy-Adjusted Dietary Inflammatory Index (E-DII) is related to both body mass index (BMI) and hyperuricemia. However, the association among BMI, hyperuricemia and DII is yet to be fully elucidated. The purpose of this study is to explore the role of BMI in the relationship between E-DII and hyperuricemia in the American population.

METHODS

A cross-sectional study was conducted using data from the National Health and Nutrition Examination Survey (NHANES) spanning from 2007 to 2016, with a sample size of 10,571 participants. The study used a weighted logistic regression model and a generalized additive model (GAM) to explore the associations among BMI, hyperuricemia and E-DII. Furthermore, mediation analysis was utilized to illustrate the mediating relationships among these variables.

RESULTS

The results of the study indicated that a higher E-DII was related to an increased risk of hyperuricemia. The association between E-DII and hyperuricemia was partially mediated by BMI.

CONCLUSIONS

E-DII is associated with hyperuricemia. BMI mediates the relationship between E-DII and hyperuricemia among Americans, which provides crucial information for the prevention of hyperuricemia.

New-onset metabolic syndrome is associated with accelerated renal function decline partially through elevated uric acid: an epidemiological cohort study

Background

The burden of metabolic syndrome (MetS) continues to rise globally and is associated with complications of multiple organ systems. We aimed to identify the association between changes in MetS status and accelerated renal function progression through a regional epidemiological survey in China, thus discovering influence factors with treatable potential.

Methods

This study was a population-based survey conducted in 2008 and 2014, assessing a representative sample of 5,225 individuals from rural areas of China. They were divided into four subgroups according to their MetS status in 2008 and 2014 (Never, Previously abnormal, New-onset, and Consistent). Multivariate logistic regression and stratification analysis evaluated the relationship between clinical factors and renal function decline under different MetS statuses. Smooth curve fitting further addressed the role of serum uric acid, illustrating the vital turning point of uric acid levels in the background of renal function deterioration.

Results

Of all groups of MetS states, the new-onset MetS showed the most significant eGFR decline, with a 6.66 ± 8.21 mL/min/1.73 m2 decrease over 6 years. The population with newly-onset MetS showed a considerable risk increase in delta eGFR with a beta coefficient of 1.66 (95%CI=1.09-2.23) after necessary correction. In searching for the drivers, the strength of the association was significantly reduced after additional adjustment for uric acid levels (β=0.91, 95%CI=0.35-1.45). Regarding the turning point, uric acid levels exceeding 426 μmol/L were more significantly associated with the stepped-up deterioration of kidney function for those with new-onset MetS.

Conclusion

Metabolic syndrome demonstrated a solid correlation with the progression of renal function, particularly in those with newly-onset MetS status. In addition to the diagnostic components of MetS, hyperuricemia could be used as a marker to identify the high risk of accelerating eGFR decline early. Furthermore, we suggested a potential renal benefit for the newly-onset MetS population when maintaining their serum uric acid level below the criteria for asymptomatic hyperuricemia.

An artificial neural network model for evaluating the risk of hyperuricaemia in type 2 diabetes mellitus

Type 2 diabetes with hyperuricaemia may lead to gout, kidney damage, hypertension, coronary heart disease, etc., further aggravating the condition of diabetes as well as adding to the medical and financial burden. To construct a risk model for hyperuricaemia in patients with type 2 diabetes mellitus based on artificial neural network, and to evaluate the effectiveness of the risk model to provide directions for the prevention and control of the disease in this population. From June to December 2022, 8243 patients with type 2 diabetes were recruited from six community service centers for questionnaire and physical examination. Secondly, the collected data were used to select suitable variables and based on the comparison results, logistic regression was used to screen the variable characteristics. Finally, three risk models for evaluating the risk of hyperuricaemia in type 2 diabetes mellitus were developed using an artificial neural network algorithm and evaluated for performance. A total of eleven factors affecting the development of hyperuricaemia in patients with type 2 diabetes mellitus in this study, including gender, waist circumference, diabetes medication use, diastolic blood pressure, γ-glutamyl transferase, blood urea nitrogen, triglycerides, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, fasting glucose and estimated glomerular filtration rate. Among the generated models, baseline & biochemical risk model had the best performance with cutoff, area under the curve, accuracy, recall, specificity, positive likelihood ratio, negative likelihood ratio, precision, negative predictive value, KAPPA and F1-score were 0.488, 0.744, 0.689, 0.625, 0.749, 2.489, 0.501, 0.697, 0.684, 0.375 and 0.659. In addition, its Brier score was 0.169 and the calibration curve also showed good agreement between fitting and observation. The constructed artificial neural network model has better efficacy and facilitates the reduction of the harm caused by type 2 diabetes mellitus combined with hyperuricaemia.

Body Mass Index and the Risk of Rheumatic Disease: Linear and Nonlinear Mendelian Randomization Analyses

OBJECTIVE

Although the association between obesity and risk of rheumatic disease is well established, the precise causal relation has not been conclusively proven. Here, we estimate the causal effect of body mass index (BMI) on the risk of developing 5 different rheumatic diseases.

METHODS

Linear and nonlinear mendelian randomization (MR) were used to estimate the effect of BMI on risk of rheumatic disease, and sex-specific effects were identified. Analyses were performed in 361,952 participants from the UK Biobank cohort for 5 rheumatic diseases: rheumatoid arthritis (n = 8,381 cases), osteoarthritis (n = 87,430), psoriatic arthropathy (n = 933), gout (n = 13,638), and inflammatory spondylitis (n = 4,328).

RESULTS

Using linear MR, we found that 1 SD increase in BMI increases the incidence rate for rheumatoid arthritis (incidence rate ratio [IRR] 1.52 [95% confidence interval (95% CI) 1.36-1.69]), osteoarthritis (IRR 1.49 [95% CI 1.43-1.55]), psoriatic arthropathy (IRR 1.80 [95% CI 1.31-2.48]), gout (IRR 1.73 [95% CI 1.56-1.92]), and inflammatory spondylitis (IRR 1.34 [95% CI 1.14-1.57]) in all individuals. BMI was found to be a stronger risk factor in women compared to men for psoriatic arthropathy (P for sex interaction = 3.3 × 10-4 ) and gout (P for sex interaction = 4.3 × 10-3 ), and the effect on osteoarthritis was stronger in premenopausal compared to postmenopausal women (P = 1.8 × 10-3 ). Nonlinear effects of BMI were identified for osteoarthritis and gout in men, and for gout in women. The nonlinearity for gout was also more extreme in men compared to women (P = 0.03).

CONCLUSION

Higher BMI causes an increased risk for rheumatic disease, an effect that is more pronounced in women for both gout and psoriatic arthropathy. The novel sex- and BMI-specific causal effects identified here provide further insight into rheumatic disease etiology and mark an important step toward personalized medicine.

Longitudinal Association between Uric Acid and Incident Sarcopenia

BACKGROUND

Sarcopenia has emerged as a significant public health concern. Uric acid (UA), as a metabolite with excellent antioxidant capacity, has been found to be associated with sarcopenia. However, the casual effects of UA on incident sarcopenia still remain unclear. Our study aimed to explore the longitudinal association between UA and incident sarcopenia among middle-aged and older adults.

METHOD

A total of 5086 participants aged ≥45 years old without sarcopenia at baseline were included from the China Health and Retirement Longitudinal Study (CHARLS). Due to the sex differences, the UA levels were analyzed by categorizing into sex-specific quartiles or by using UA levels as a continuous variable (per 1 mg/dL). The longitudinal association between UA and incident sarcopenia was evaluated using Cox proportional hazards regression models.

RESULTS

During the 4-year follow-up period, 552 (10.85%) participants with incident sarcopenia were identified, of which 370 cases were males and 182 cases were females. Compared to the first quartile (Q1) UA levels, the Q3 and Q4 UA levels were significantly associated with lower risk of incident sarcopenia in males (Q3: adjusted hazard ratio (HR), 0.72; 95% CI (confidence interval), 0.54-0.97; Q4: HR, 0.57; 95% CI, 0.41-0.80). When UA was as a continuous variable (per 1 mg/dL), the association in males remained significant (HR: 0.87; 95% CI: 0.79-0.97). No significant association was observed in females.

CONCLUSION

Our findings indicated that UA was negatively associated with incident sarcopenia in males but not in females among middle-aged and older Chinese.

Association between statin use and the risk of gout in patients with hyperlipidemia: A population-based cohort study

Objective: To investigate the association between statin use and risk of gout in patients with hyperlipidemia. Methods: In this population-based retrospective cohort study, patients ≥20 years and diagnosed as having incident hyperlipidemia between 2001 and 2012 were identified from the 2000 Longitudinal Generation Tracking Database in Taiwan. Regular statin users (incident statin use, having 2 times and ≥90 days of prescription for the first year) and two active comparators [irregular statin use and other lipid-lowering agent (OLLA) use] were compared; the patients were followed up until the end of 2017. Propensity score matching was applied to balance potential confounders. Time-to-event outcomes of gout and dose- and duration-related associations were estimated using marginal Cox proportional hazard models. Results: Regular statin use non-significantly reduced gout risk compared with irregular statin use (aHR, 0.95; 95% CI, 0.90-1.01) and OLLA use (aHR, 0.94; 95% CI, 0.84-1.04). However, a protective effect was noted for a cumulative defined daily dose (cDDD) of >720 (aHR, 0.57; 95% CI, 0.47-0.69 compared with irregular statin use and aHR, 0.48; 95% CI, 0.34-0.67 compared with OLLA use) or a therapy duration of >3 years (aHR, 0.76; 95% CI, 0.64-0.90 compared with irregular statin use and aHR, 0.50; 95% CI, 0.37-0.68 compared with OLLA use). Dose- and duration-dependent associations were consistent in the 5-year sensitivity analyses. Conclusion: Although statin use was not associated with a reduction in gout risk, the protective benefit was observed in those receiving higher cumulative doses or with a longer therapy duration.

J-Shaped Relationship of Serum Uric Acid with Unfavorable Short-Term Outcomes among Patients with Acute Ischemic Stroke

(1) Background: The role of uric acid in stroke outcomes remains inconclusive. (2) Methods: We retrospectively enrolled 3370 patients with acute ischemic stroke. (3) Results: Uric acid level was higher in men than in women. Univariate analyses revealed that the rates of hyperuricemia were higher in all patients and in women for unfavorable outcomes. For death, the hyperuricemia rates were higher in all patients including men and women, and the uric acid levels were also higher in all patients and in women. A J-shaped curve was observed between uric acid and the discharge-modified Rankin Scale score. Patients within Quartiles 1 (<4.1 mg/dL) and 4 (>6.5 mg/dL) of uric acid had higher rates of unfavorable outcomes and death than patients within Quartiles 2 (4.1−5.1 mg/dL) and 3 (5.1−6.2 mg/dL). Multivariable analyses for unfavorable outcomes revealed that Quartile 1 of uric acid was a significant factor in all patients and in men. In men, a significant factor for death was being in Quartile 1 of uric acid. In women, higher levels of uric acid or hyperuricemia (>6.6 mg/dL) were significant factors for death. (4) Conclusions: Lower uric acid levels are a predictor for unfavorable outcomes and death in men, and higher uric acid levels are a predictor for death in women.

Effects of vitamin C supplementation on gout risk: results from the Physicians' Health Study II trial

BACKGROUND

Short-term randomized trials suggest that a 500 mg/d vitamin C supplement reduces serum urate, whereas observational studies show vitamin E is inversely associated with gout risk.

OBJECTIVES

We evaluated the effect of supplemental vitamin C (prespecified primary exposure) and vitamin E (prespecified secondary exposure) on new diagnoses of gout.

METHODS

We performed a post hoc analysis of data from the Physicians' Health Study II, a randomized, double-blind, placebo-controlled factorial trial of randomized vitamin C (500 mg/d) and vitamin E (400 IU every other day). The primary outcome was new gout diagnoses, self-reported at baseline and throughout the follow-up period of ≤10 y.

RESULTS

Of 14,641 randomly assigned male physicians in our analysis, the mean age was 64 ± 9 y; 1% were Black, and 6.5% had gout prior to randomization. The incidence rate of new gout diagnoses during follow-up was 8.0 per 1000 person-years among those assigned vitamin C compared with 9.1 per 1000 person-years among those assigned placebo. The vitamin C assignment reduced new gout diagnoses by 12% (HR: 0.88; 95% CI: 0.77, 0.99; P = 0.04). These effects were greatest among those with a BMI <25 kg/m 2 (P-interaction = 0.01). Vitamin E was not associated with new gout diagnoses (HR: 1.05; 95% CI: 0.92, 1.19; P = 0.48).

CONCLUSIONS

Vitamin C modestly reduced the risk of new gout diagnoses in middle-aged male physicians. Additional research is needed to determine the effects of higher doses of vitamin C supplementation on serum urate and gout flares in adults with established gout.The Physicians' Health Study II is registered at clinicaltrials.gov (identifier: NCT00270647).

The effect of trajectory of serum uric acid on survival and renal outcomes in patients with stage 3 chronic kidney disease

Uric acid (UA) is associated with renal disease and patient survival, but the causal associations remain unclear. Also, the longitudinal UA control (trajectory) is not well understood. We enrolled 808 subjects diagnosed with stage 3 chronic kidney disease from 2007 to 2017. We plotted the mean UA over a period of 6 months with a minimum requirement of 3 samples of UA. From the sampled points, we generated an interpolated line for each patient by joining mean values of UA levels over time. Using lines from all patients, we classified them into 3 groups of trajectories (low, medium, and high) through group-based trajectory modeling, and then we further separated them into either treatment or nontreatment subgroups. Due to multiple comparisons, we performed post hoc analysis by Bonferroni adjustment. Using univariate competing-risks regression, we calculated the competing risk analysis with subdistribution hazard ratio of possible confounders. All of the 6 trajectories appeared showed a gradual decline in function over time without any of the curves crossing over one another. For all-cause mortality risk, none of the variables (including age, gender, coronary arterial disease, cerebrovascular disease, diabetes mellitus, renin-angiotensin-aldosterone system inhibitors, trajectories of UA, and treatment of UA) were statistically significant. All 6 trajectories appeared as steady curves without crossovers among them over the entire period of follow-up. Patients with diabetes mellitus were statistically more likely to undergo dialysis. The only trend was seen in the on-treatment trajectories, which showed lower risks for dialysis compared to their nontreatment trajectories. There was no effect of UA control on survival. Initial treatment of UA is crucially important for UA control. However, the long-term effects on patients and renal survival appeared to be minor and without statistical significance.

Hyperuricemia Associated with Low Skeletal Muscle in the Middle-Aged and Elderly Population in China

BACKGROUND

Previous studies have presented inconsistent results on the relationship between serum uric acid and skeletal muscle mass (SMM). We aimed to explore whether a higher serum uric acid level was associated with low SMM in the Chinese population.

METHODS

We performed a cross-sectional analysis of 6595 subjects aged 45 years or older. They were tested for fasting blood glucose, total cholesterol, triglycerides, high-density lipoprotein-cholesterol, low-density lipoprotein-cholesterol, uric acid, blood urea nitrogen, creatinine, and estimated glomerular filtration rate. SMM was accessed by dual-energy x-ray absorptiometry using two approaches: weight-adjusted appendicular skeletal muscle mass (ASM)% and ASM/BMI (body mass index (kg/m²)). Low SMM was defined as a cut-off point of ASM/BMI<0.789 for men and<0.512 for women.

RESULTS

Compared with their normal group, patients with hyperuricemia had lower ASM% (29.33±2.33 vs 30.03±2.34 for males and 24.71±1.99 vs 25.19±2.07 for females, P<0.01) and ASM/BMI (0.83±0.10 vs 0.85±0.10 for male and 0.60±0.07 vs 0.62±0.07 for female), with a higher prevalence of the associated low SMM in both sexes (35.2 vs 26.5% for male and 10.5 vs 5.9% for female, P<0.01). Pearson analysis showed that ASM% and ASM/BMI were negatively correlated with SUA (male: ASM/BMI, r=-0.097, ASM%, r=-0.146; female: ASM/BMI, r=-0.151, ASM%, r=-0.157; all P<0.001). Logistic regression analysis showed a positive association of hyperuricemia with adjusted risk of low SMM association.

CONCLUSIONS

In a middle-aged and elderly Chinese population, hyperuricemia is independently and positively associated with low SMM and can vary by age and gender.

Longitudinal development of incident gout from low-normal baseline serum urate concentrations: individual participant data analysis

INTRODUCTION

Elevated serum urate (SU) concentration is the central risk factor for the development of gout. The aim of this study was to examine the incidence of gout in people with low and normal SU levels (< 7.00 mg/dL).

METHODS

Longitudinal cohort data from the Atherosclerosis Risk in Communities Study (ARIC), Coronary Artery Risk Development in Young Adults Study (CARDIA), and both the Original and Offspring cohorts of the Framingham Heart Study (FHS) were used to determine incident gout by baseline SU over 3, 5, 10, 12 and 15 year periods. A Cox proportional hazards model with covariables of age, gender, ethnicity, and cohort was calculated to report the hazard ratios (HR) for incident gout.

RESULTS

The incidence of gout at 15 years for a baseline SU < 4.00 mg/dL was 0.59%, 4.00-4.49 mg/dL was 1.28%, 4.50-4.99 mg/dL was 0.86%, 5.00-5.49 mg/dL was 0.94%, 5.50-5.99 mg/dL was 1.52%, 6.00-6.49 mg/dL was 2.91%, 6.50-6.99 mg/dL was 3.2%, and > 7.00 mg/dL was 12.2%. In an adjusted Cox proportional hazards model, compared to the referent baseline SU < 4.00 mg/dL, there was a non-significant increase in incident gout for baseline SU bands between 4.00-5.49 mg/dL, whereas incident gout was significantly increased for SU 5.50-5.99 mg/dL (HR 2.60), 6.00-6.49 mg/dL (HR 3.70), 6.50-6.99 mg/dL (HR 5.24) and > 7.00 mg/dL (HR 18.62).

CONCLUSION

A baseline SU of 5.50 mg/dL or more is a risk factor for development of gout over 15 years. However, incident gout does occur over time in a small proportion of people with lower baseline SU levels.

Daytime Napping Duration Is Positively Associated With Risk of Hyperuricemia in a Chinese Population

CONTEXT

Loss of sleep or disturbance of sleep-wake cycles has been related to metabolic impairments. However, few studies have investigated the association between daily sleep duration and hyperuricemia.

OBJECTIVE

We investigated daily sleep duration (daytime napping and nocturnal sleep) with hyperuricemia risk.

METHODS

We cross-sectionally analyzed data from the China Multi-Ethnic Cohort (CMEC), Yunnan region. A total of 22 038 participants aged 30 to 79 years were recruited in 2018. Hyperuricemia was defined as serum uric acid (SUA) above 7.0 mg/dL in men and above 6.0 mg/dL in women. Outcomes were associations between daily sleep duration and hyperuricemia.

RESULTS

We found that the longest daytime napping duration was associated with a higher risk of hyperuricemia in the crude model (odds ratio [OR] [95% CI], 2.22 [1.88-2.61], P < .001) and in a multivariable adjustment model (OR, 1.69; 95% CI, 1.41-2.01, P < .001) after adjusting for demographic, sleep habits, and metabolic risk factors. The association was moderately attenuated with additionally adjusted for serum creatinine (OR, 1.54; 95% CI, 1.28-1.86, P < .001). Longer daytime napping duration was also related to higher risk of hyperuricemia combined with metabolic syndrome (MetS). Respondents in the group with daytime napping duration greater than or equal to 90 minutes presented with a higher risk of hyperuricemia combined with MetS (OR, 1.39; 95% CI, 1.06-1.79; P < .001) in the fully adjusted model. We did not observe any relation between nocturnal sleep duration and risk of hyperuricemia in the study.

CONCLUSION

Longer daytime napping duration (but not nocturnal sleep duration) was independently associated with risk of hyperuricemia in a Chinese population.

Hypouricemia and Mortality Risk in the US General Population

OBJECTIVE

The most recent European Alliance of Associations for Rheumatology (EULAR) recommendations for gout advise against maintaining a serum urate (SU) level of <3 mg/dl for prolonged periods of time. While several Asian cohort studies have shown higher rates of mortality in individuals with extremely low SU levels, data from non-Asian cohort studies are scarce, and the relationship between hypouricemia, cardiovascular risk, and mortality remains unclear.

METHODS

Using data collected from the 1988-1994 and 1999-2008 National Health and Nutrition Examination Survey (NHANES), we examined the relationship between SU level and overall and cause-specific mortality in 41,807 adults in the US. We calculated multivariable hazard ratios (HRs) that were compared to a referent SU level of 5-6 mg/dl for SU categories <4, 4-5, 6-7, 7-8, and >8 mg/dl in men and SU categories <3, 3-4, 4-5, 6-7, and >7 mg/dl in women.

RESULTS

A higher mortality risk was not observed in women who had an SU level of <3 mg/dl (HR 1.09 [95% confidence interval (95% CI) 0.92-1.28]). A 28% higher mortality risk was observed in men who had an SU level of <4 mg/dl (HR 1.28 [95% CI 1.13-1.45]), with a nearly three-times higher mortality risk from diabetes mellitus also noted (HR 2.89 [95% CI 1.59-5.23]), but no increase in mortality from any other specific cause.

CONCLUSION

We found no long-term excess mortality risk among American women with SU levels as low as <3 mg/dl, a finding which is incompatible with the notion of a causal relationship between hypouricemia and premature mortality in women. We found excess all-cause mortality and diabetes mellitus-related mortality among hypouricemic American men, which may in part be attributable to the uricosuric effect of hyperglycemia in fatal uncontrolled diabetes mellitus (analogous to reverse causality).

Analyzing the Association between Hyperuricemia and Periodontitis: A Cross-Sectional Study Using KoGES HEXA Data

Hyperuricemia arises from the buildup of excessive uric acid in the blood, and it is implicated in the development of periodontitis. The objective of this study was to investigate the association between hyperuricemia and periodontitis using a cross-sectional study design and Korean Genome and Epidemiology Study Health Examinee (KoGES HEXA) data. This prospective cohort study used epidemiological data from the KoGES from 2004 to 2016. Among 173,209 participants, 8809 with hyperuricemia and 126,465 controls (non-hyperuricemia) were selected. This study defined hyperuricemia as >7.0 mg/dL of uric acid in men and >6.0 mg/dL in women. This study analyzed the history of periodontitis among hyperuricemia and control participants. Participants’ age, gender, income, obesity, smoking, alcohol consumption, and nutritional intake were all examined. Chi-square tests, independent t-tests, and two-tailed analyses were used for statistical analysis. The adjusted OR (aOR) of hyperuricemia for periodontitis was 0.89 (95% confidence interval (CI) = 0.81–0.96, p = 0.005). This study demonstrated that hyperuricemia was associated with periodontitis. This finding meant that elevated uric acid levels could have a positive effect on periodontitis. However, further studies should be performed to determine the range of uric acid levels beneficial to periodontal health.

Gender equality and global health: intersecting political challenges

Background

Women’s and men’s health outcomes are different. Some differences are biological, related to male and female sex, while others are related to their gender. Sex- and gender-related issues require different solutions, but policy makers lack straightforward heuristic strategies to identify gender-related health inequities.

Methods

Using 169 causes of disability-adjusted life years (DALYs) from the 2017 Global Burden of Disease, we calculated the female-to-male (f:m) and male-to-female (m:f) ratios of global DALYs, rank-ordered the ratios by size and calculated the proportion of all-cause DALYs that each cause explained, separately for males and females 15-49 years old. Gender-related vs sex-related causes were categorised using literature on the drivers for the 15 causes with highest f:m and m:f ratios.

Results

Causes of DALYs with high m:f ratios appear to be gendered and include: road injuries, interpersonal violence, and drowning – totaling 12.4% of men’s (15-49 years) all-cause DALYs. However, causes of DALYs with high f:m ratios are more likely a mix of sex-related and gender-related factors – including headache disorders, depressive disorders, and dietary iron deficiency – totaling 13.4% of women’s (15-49 years) all-cause DALYs. Ratios vary by age, geography and Socio-demographic Index.

Conclusions

Gender-related vs sex-related causes were categorised using available literature on the drivers for selected causes, illustrating that sex-disaggregated data represents a mix of social and biological influences. This analysis offers a model that policy makers can use to uncover potential gender inequalities in health, including intersections with other social factors. From it, new challenges emerge for global health policy makers and practitioners willing to address them. Global health actors will need to achieve a balance between the two agendas of global health and gender equality.

Diabetes Mellitus Is Associated with a Lower Risk of Gout: A Meta-Analysis of Observational Studies

AIMS

Although several epidemiological studies have investigated the relationship between diabetes mellitus (DM) and the risk of gout, the results are inconsistent. Therefore, we systematically retrospected available observational studies to clarify the impact of DM on the risk of gout.

METHODS

Embase, PubMed, Cochrane Library, Scopus, Web of Science, and China National Knowledge Infrastructure were searched for relevant articles from inception to 2 March 2020. The quality of the included studies was assessed using the Newcastle-Ottawa Quality Assessment Scale. The multivariate adjusted relative risks (aRR) and corresponding 95% confidence intervals (CI) were pooled based on a random-effect model. Cochran's Q test and I ² were used to evaluate heterogeneity.

RESULTS

Five studies involving 863,755 participants were included in our meta-analysis. DM was associated with a lower risk of gout (aRR: 0.66; 95% CI: 0.59 to 0.73) but had a high heterogeneity (I ² = 89.2%). Metaregression analysis revealed that the types of DM were the source of heterogeneity. Subgroup analysis by types of DM showed that the risk of gout was significantly lower in type 1 DM (T1DM) (aRR: 0.42; 95% CI: 0.28 to 0.63) than in type 2 DM (T2DM) (aRR: 0.72; 95% CI: 0.70 to 0.74). Furthermore, when stratified according to gender in DM, sex-specific association was found. The inverse association was observed in males only (aRR: 0.57; 95% CI: 0.43 to 0.77) and not in females (aRR: 0.96; 95% CI: 0.87 to 1.05). Further stratified based on glycated hemoglobin (HbA1c) levels in DM, raised A1C levels were associated with a reduced risk of gout in patients with DM.

CONCLUSIONS

This meta-analysis indicated that DM was related to a lower risk of gout, and the protective effect of DM on the risk of gout was stronger in males, T1DM, or DM with high HbA1c levels. However, more prospective cohort studies are required to confirm these results.

The association of serum uric acid levels in psoriasis patients: A systematic review and network meta-analysis

BACKGROUND

Current research has proved that psoriasis is associated with serum uric acid (SUAC) levels. Our purpose is to clarify SUAC levels and the incidence of hyperuricemia in psoriasis patients, and to compare SUCA levels in different groups' psoriasis patients.

METHODS

We plan to search 7 electronic bibliographic databases (PubMed, Embase, Cochrane, and 4 Chinese databases) from inception to August 2019. Literatures selection and data collection will be performed independently by 2 authors. The Newcastle-Ottawa scale will be used to assess the methodologic quality and bias of included studies. Firstly, standard pairwise meta-analysis will be used to examine the considered data synthesis. Secondly, if the identified studies appear sufficiently similar within and across the different comparisons between different groups of psoriasis patients, we will estimate SUAC levels using network meta-analysis in different age and ethnicity psoriasis patients. Mean difference, risk ratio, and 95% confidence intervals will be used to assess the SUAC levels and the incidence of hyperuricemia in psoriasis patients. The software of Stata and WinBUGS will be used to calculations.

RESULTS

The results will be published in a peer-reviewed journal.

CONCLUSION

Our study will compare SUCA levels in different groups' psoriasis patients through network meta-analysis, and we believe our job is very meaningful.

ETHICS AND DISSEMINATION

Our study is a secondary study of the existing literature. So, ethical and dissemination approval is not required.

Gout is not associated with the risk of fracture: a meta-analysis

BACKGROUND

Numerous quantitatively based studies measuring the association between gout and the risk of fractures remain inconclusive. In order to determine whether gout could increase the risk of fractures, a meta-analysis was performed systematically.

METHODS

Electronic databases, MEDLINE/PubMed, Embase, and Cochrane Library were systematically searched to identify studies evaluating the association of gout and the risk of fractures. No restrictions on language, publication date, or journal of publication were imposed. Meta-analysis was performed to pool the outcome estimates of interest such as fracture incidence, fracture risk, and fracture risk in different sites and at different time points in the follow-up period.

RESULTS

Screening determined that seven studies involving a total of 684,964 participants (151,002 in the gout group and 533,962 in the control group) were deemed viable for inclusion in the meta-analysis. The results of the analysis showed that gout would not significantly have a relatively higher risk of any fracture (RR = 1.11, 95% CI 0.98-1.26). Subgroup analysis showed consistent results for sexuality (female: RR = 1.13, 95% CI 0.93-1.37; male: RR = 0.99, 95% CI 0.91-1.07) and several occurring sites (humerus, wrist, vertebra, hip, upper limbs, and lower limbs). Additionally, the results demonstrated that urate-lowering drugs prescribed early during disease had neither adverse nor beneficial effect on the long-term risk of fractures (RR = 0.89, 95% CI 0.76-1.05).

CONCLUSIONS

This meta-analysis confirmed that gout was not associated with an increased risk of fractures. Urate-lowering drugs prescribed early during the course of disease had neither adverse nor beneficial effect on the long-term risk of fractures.

Association of the ESR1 polymorphism with menopause and MLXIPL genetic variant influence serum uric acid levels in Slovak midlife women

OBJECTIVE

This study examines associations between the ESR1 (XbaI, PvuII) and the MLXIPL (rs3812316) gene polymorphisms, and uric acid (UA) levels in Slovak midlife women, subdivided according to their menopause status.

METHODS

We assessed a total of 362 women from 38 to 65 years of age. Women were recruited from different localities in the western and middle parts of Slovakia. Participants were interviewed during their medical examination at local health centers. They were investigated with respect to a variety of aspects such as medical, anthropometrical, and lifestyle. Participants provided a blood sample for biochemical analyses and DNA genotyping. The MLXIPL gene (rs3812316 SNP variant) and ESR1 gene (PvuII and XbaI) genotypes were then detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Data were analyzed using general linear models and multiple linear regression analyses to adjust for risk factors elevating the UA level such as fat mass (FM), triglycerides (TGs) and creatinine.

RESULTS

A positive association between MLXIPL and UA level was observed in the total sample of women after control for confounding covariates, including FM, TGs, and creatinine (P = 0.027). Women with the CC genotype had higher UA levels than the G-allele carriers (261.5 μmol/L ± 68.3 vs 241.1 μmol/L ± 55.1 P = 0.013). A statistically significant association was noticed between postmenopause status and the ESR1 XbaI genotype and their effect on UA (P = 0.028). The Bonferroni pairwise comparison determined that the G-allele carriers in the postmenopausal period had higher estimated UA marginal mean (269.7 μmol/L) than the AA-allele postmenopausal women (236.5 μmol/L) (P = 0.012). The estimated UA marginal mean showed a significant increasing trend according to the MS in G allele carriers (248.5 μmol/L in pre/peri-menopausal vs 269.7 μmol/L in postmenopausal, P = 0.009). In contrast, a decreasing trend was observed in AA carriers (250.6 μmol/L in pre/perimenopausal women vs 236.5 μmol/L in postmenopausal). However, this trend was not statistically significant (P = 0.288).

CONCLUSIONS

This cross-sectional study suggests that MLXIPL (rs3812316) polymorphism is associated with higher serum UA levels and that the ESR1 (XbaI) polymorphism is associated with UA levels only in the postmenopausal cohort.

Gender-specific risk factors for gout: a systematic review of cohort studies

BACKGROUND

Though gout is more prevalent in men than women, it remains unclear whether gender influences risk factors for incident gout. We aimed to systematically review all cohort studies examining risk factors for the development of gout by gender.

METHODS

MEDLINE, EMBASE, CINAHL and the Cochrane Library were searched from inception to March 2019. Risk factors for gout examined were: age, ethnicity, consumption of alcohol, meat, seafood, dairy products, purine-rich vegetables, coffee and fructose, vitamin C intake, the Dietary Approaches to Stop Hypertension (DASH) diet, metabolic syndrome, BMI, waist and chest circumference, waist-to-hip ratio, weight change, diabetes mellitus, dyslipidaemias, renal disease, psoriasis, hypertension, diuretic use and anti-diabetic medication. Cohort studies were included if examining (at least) one of these risk factors for gout in either gender in the general population or primary care. Sample characteristics from included articles and their reported risk estimates were described using narrative synthesis.

RESULTS

Thirty-three articles were included, 20 (60.6%)directly compared risk factors by gender, 10 (30.3%) used men-only samples, 3 (9.1%) used women-only samples. Articles comparing risk across genders found similar increases in most risk factors. However, in men, metabolic syndrome (Hazard Ratio (95% CI) 1.37(1.20-1.58)) presented a risk of incident gout compared to none in women (> 50 years 1.15(0.85-1.54); ≤50 years 1.29(0.76-2.17)). Compared to men, women showed greater associated risk with higher consumption of fish and shellfish (HR (95% CI) Men: 1.02 (0.86-1.22); Women 1.36 (1.12-1.65)).

CONCLUSIONS

Risk factors for developing gout did not typically differ between genders and therefore similar preventative advice can be provided. Exceptions were metabolic syndrome in men and excessive seafood consumption in women, but these singular articles need further examination and in general more research into the risk factors for gout which includes women is required.

Reference interval and upper decission limit for serum uric acid – an evidence-based approach on Romanian population using an a posteriori method

Introduction. There is accumulating evidence that high normal serum uric acid (SUA) levels of 6-7 mg/dL are associated with cardiovascular morbidity and metabolic syndrome (MetS), hence the need to redefine its upper limit of normal (ULN). We aimed to derive ULN based on statistics and evidence in a representative sample of the population and to observe its relation to MetS components.

Methods. All SUA measurements form a university rheumatology hospital were extracted between January 5th 2010 and March 21st 2018. SUA levels were measured by a single biochemist a unique type of commercially available kit. Follow-up measurements, patients with diagnoses influencing SUA levels and outlying measurements were excluded. ULNs were studied using least square analysis.

Results. Of the 22503 SUA measurements in the database, only 3318 came from normal individuals: 33.3% men (n=1105), 66.7% women (n = 2213). Least square analysis revealed the following SUA reference intervals (RI): 3.43-6.19 mg/dL for the combined sample; 4.44-7.01 mg/dL for men, 3.28-5.56 mg/dL for women. The values corresponding to the 66th percentile of each group presented lower ULNs: 5.36 mg/dL for all, 6.10 mg/dL for men, 4.90 mg/dL for women. The prevalence of hyperuricemia increased from 13.8% (manufacturer’s gender-specific ULN) to 19.9% (derived ULN). Mean SUA levels significantly increased with the number of MetS components.

Conclusion. We recommend that hyperuricemia should be defined using a statistical approach of ULN selection corresponding to the genderand population-specific 66th percentile of data range.

Differential risk group of developing stroke among older women with gouty arthritis: A latent transition analysis

OBJECTIVE

Gout-related comorbidities are intricate and its clinical features may demonstrate sex difference; however, few studies have evaluated the links between comorbidities and gout in a female population. The objectives of this study were to compare the aggregation and transitive trajectories of comorbidities of gout, and their consequences in female and male gout populations.

METHODS

A prospective cohort study was conducted using data from the Taiwan National Health Insurance Research Database. A female and male gout population were followed up from 2000 to 2009 to identify the comorbidities of cardiovascular disease, hyperlipidemia, hypertension, diabetes mellitus (DM) and chronic kidney disease. The cumulative incidence of stroke from 2000 to 2010 was examined. A latent trajectory analysis was used to determine the transitive trajectories of the comorbidities of gout.

RESULTS

Both female and male patients with gout had five risk cluster transition (CT) phenotypes of comorbidities within 10-year follow-up: CT1 and CT2, with various persistent comorbidities; CT3, with few persistent comorbidities; and CT4 and CT5, with transfer to cluster 1 from other clusters. The female participants in CT2 predominantly experienced DM and were associated with significantly increased risk of developing stroke.

CONCLUSION

Diabetes is a notable risk factor for the development of stroke in female patients with gout. Early assessment and management for the comorbidities of gout, particularly in DM, would effectively reduce future stroke risk in female gout population.

NLRP3 inflammasome and lipid metabolism analysis based on UPLC-Q-TOF-MS in gouty nephropathy

To determine the differences in plasma metabolism between healthy patients and patients with hyperuricaemia and gouty nephropathy, the present study identified differentially expressed metabolites associated with gouty nephropathy. Furthermore, the NLRP3 inflammasome signalling pathway in gouty nephropathy was explored, and the mechanism of hyperuricaemia-induced renal damage. Adult male patients examined between July 2016 and June 2017 were selected as the patient cohort for the present study from the Affiliated Bao'an Hospital of Shenzhen, Southern Medical University (Shenzhen, China). These patients were divided into three groups of 30 patients each: Control, hyperuricaemia and gouty nephropathy groups. The expression levels of NLRP3, ASC and caspase-1 mRNA and protein were detected in peripheral blood mononuclear cells, and the plasma levels of IL-1β and IL-18. Ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry was used to determine differential levels of metabolites between patients from different groups, in order to identify potential biomarkers. The expression of the NLRP3 inflammasome in peripheral blood mononuclear cells, and the levels of IL-1β and IL-18 in the plasma were increased in the gouty nephropathy group compared with the control and hyperuricaemia groups. In addition, 46 metabolites were identified as potential plasma metabolic biomarkers that were able to distinguish gouty nephropathy from hyperuricaemia. The majority of these metabolites were involved in lipid metabolism, in particular the activity of phospholipase A2 and β-oxidation. These data indicated that lipid metabolism and the NLRP3 inflammasome serve a pivotal role in gouty nephropathy. In addition, the results suggested that lipids may mediate the progression of gouty nephropathy through the activity of phospholipase A2, β-oxidation and activation of the NLRP3 inflammasome.

The Prevalence of Hyperuricemia Sharply Increases from the Late Menopausal Transition Stage in Middle-Aged Women

The impact of menopausal transition on change of serum uric acid level remains unknown. The present study evaluated the relationship of menopausal stages with prevalent hyperuricemia in middle-aged women. This cross-sectional study included 58,870 middle-aged Korean women, aged ≥40, who participated in a health examination from 2014 to 2016. Menopausal stages were obtained with a standardized, self-administered questionnaire and were categorized according to the criteria of the Stages of Reproductive Aging Workshop (STRAW+10). Hyperuricemia was defined as a serum uric acid level of ≥6 mg/dL. The prevalence of hyperuricemia increased as menopausal stage increased. The multivariable-adjusted odds ratios (95% confidence intervals) for prevalent hyperuricemia comparing early transition, late transition, and post-menopause to pre-menopause were 1.19 (0.80–1.77), 2.13 (1.35–3.36), and 1.65 (1.33–2.04), respectively. This association was stronger among non-obese compared to obese participants and in those with low high-sensitivity C-reactive protein (hsCRP) levels (<1.0 mg/L) compared to those with elevated hsCRP levels of ≥1.0 mg/L (p for interaction = 0.01). In this large sample of middle-aged women, the prevalence of hyperuricemia significantly increased from the menopausal stage of late transition, independent of potential confounders. Appropriate preventive strategies for reducing hyperuricemia and its related consequences should be initiated prior to menopause.

Joint Clinical Consensus Statement of the American College of Foot and Ankle Surgeons® and the American Association of Nurse Practitioners®: Etiology, Diagnosis, and Treatment Consensus for Gouty Arthritis of the Foot and Ankle

Gout is a condition that commonly affects the foot and ankle, and practitioners who treat these structures should be aware of the methods to diagnose and treat this form of arthritis. Practitioners also need to recognize extra-articular manifestations of the disease. Although the acutely red, hot, swollen joint is a common presentation, chronic tophaceous gout can be associated with pain, nodule formation, and cutaneous compromise. Since the underlying causes that lead to excessive monosodium urate deposition may be treatable, early and accurate diagnosis can be very beneficial and may even prevent articular degeneration.

The risk of clinically diagnosed gout by serum urate levels: results from 30 years follow-up of the Malmö Preventive Project cohort in southern Sweden

Background

Hyperuricemia (HU) is in the causal pathway for developing clinical gout. There are few population-based assessments of the absolute and relative risk of clinically diagnosed incident gout in subjects with HU. We aimed to explore the long-term risk of developing incident gout among asymptomatic adults with different levels of serum urate (SU).

Methods

Malmö Preventive Project was a population-based screening program for cardiovascular risk factors, alcohol abuse, and breast cancer in Malmö, Sweden. The study population was screened between 1974 and 1992. At baseline, subjects were assessed with a questionnaire, physical examination, and laboratory tests. Follow-up ended at first gout diagnosis, death, moving from area, or December 31, 2014. Incident gout (using ICD10 codes) was diagnosed based on national registers for specialized inpatient and outpatient care, and from 1998 onward in the Skåne Healthcare Register including primary healthcare. Incidence rates, absolute risk, hazard ratios (HRs) and potentially associated factors were analyzed by baseline SU levels, i.e. normal levels (≤ 360 μmol/L); 361–405 (levels below tissue solubility of SU), and > 405 (HU), overall, and by sex.

Results

Overall, 1275 individuals [3.8%; 1014 men (4.5%) and 261 women (2.4%)] of the 33,346 study participants (mean age: 45.7 (SD: 7.4), 67% men), developed incident gout during follow-up (mean 28.2 years). Of those with HU, 14.7% of men and 19.5% of women developed gout. Compared to subjects in the lowest SU category, the age-adjusted HR in men increased from 2.7 to 6.4, and in women from 4.4 to 13.1 with increasing baseline SU category, and with a statistically significant interaction of sex (p < 0.001). Body mass index, estimated glomerular filtration rate (negative), triglycerides, alcohol risk behavior (only in men), and comorbidities such as hypertension, cardiovascular disease, and diabetes were strongly associated with SU at baseline in both sexes.

Conclusions

The absolute risk for developing clinically diagnosed gout over 30 years in middle-aged subjects was 3.8%, and increased progressively in both men and women in relation to baseline SU. This risk increase was significantly higher in women than in men, whereas the associations between baseline risk markers and SU levels were similar in both sexes.

Effects of a Dietary Approach to Stop Hypertension (DASH) Diet Intervention on Serum Uric Acid in African Americans With Hypertension

OBJECTIVE

To examine whether partial replacement of a diet typical of the average American diet with Dietary Approaches to Stop Hypertension (DASH)-related foods in the home environment lowers the serum uric acid (UA) level in individuals with hypertension.

METHODS

We conducted an ancillary study of a randomized trial of African American adults with controlled hypertension from an urban clinic. Participants were assigned to either a control group or an intervention (DASH-Plus) group. DASH-Plus participants received coach-directed dietary advice, assistance with purchasing DASH-related foods ($30/week), and home delivery of food via a community supermarket. Participants in the control group received a DASH diet brochure and a debit card account ($30/week) to purchase foods. Serum UA levels were measured at baseline and after 8 weeks.

RESULTS

Of the original 123 randomized participants, 117 had available serum UA measurements. Seventy percent of the participants were women, the mean ± SD age was 59 ± 9.5 years, and the mean ± SD serum UA level was 6.4 ± 1.7 mg/dl. The DASH-Plus diet did not reduce serum UA levels compared with the control diet (difference in difference -0.01 mg/dl [95% confidence interval -0.39, 0.38]). However, there was a significant trend toward a greater reduction in the serum UA level in participants with higher baseline serum UA levels (P for trend = 0.008). Baseline changes in the serum UA level were inversely associated with changes in systolic blood pressure (P = 0.002), diastolic blood pressure (P = 0.001), and urinary sodium excretion (P = 0.05).

CONCLUSION

Overall, in African American individuals, partial replacement of a typical diet with DASH foods did not lower serum UA levels compared with a control diet. However, there was a significant trend toward a greater reduction in serum UA levels in subjects with higher baseline serum UA levels. Furthermore, changes in serum UA levels were associated with known correlates, suggesting heterogeneity of effects in the treatment and control arms. Future pragmatic studies of consumption of the DASH diet to lower serum UA levels should optimize replacement strategies and enroll individuals with hyperuricemia or gout.

Obesity, hypertension and diuretic use as risk factors for incident gout: a systematic review and meta-analysis of cohort studies

Background

Gout treatment remains suboptimal. Identifying populations at risk of developing gout may provide opportunities for prevention. Our aim was to assess the risk of incident gout associated with obesity, hypertension and diuretic use.

Methods

We conducted a systematic review and meta-analysis of prospective and retrospective cohort studies in adults (age ≥ 18 years) from primary care or the general population, exposed to obesity, hypertension or diuretic use and with incident gout as their outcome.

Results

A total of 9923 articles were identified: 14 met the inclusion criteria, 11 of which contained data suitable for pooling in the meta-analysis. Four articles were identified for obesity, 10 for hypertension and six for diuretic use, with four, nine and three articles included respectively for each meta-analysis. Gout was 2.24 times more likely to occur in individuals with body mass index ≥ 30 kg/m² (adjusted relative risk 2.24 (95% confidence interval) 1.76–2.86). Hypertensive individuals were 1.64 (1.34–2.01) and 2.11 (1.64–2.72) times more likely to develop gout as normotensive individuals (adjusted hazard ratio and relative risk respectively). Diuretic use was associated with almost 2.5 times the risk of developing gout compared to no diuretic use (adjusted relative risk 2.39 (1.57–3.65)).

Conclusions

Obesity, hypertension and diuretic use are risk factors for incident gout, each more than doubling the risk compared to those without these risk factors. Patients with these risk factors should be recognised by clinicians as being at greater risk of developing gout and provided with appropriate management and treatment options.

U-Shaped Association Between Serum Uric Acid Level and Risk of Mortality: A Cohort Study

OBJECTIVE

In addition to the controversy regarding the association of hyperuricemia with cardiovascular disease (CVD) mortality, few studies have examined the impact of a low uric acid level on mortality. We undertook the present study to evaluate the relationship between both low and high uric acid levels and the risk of all-cause and cause-specific mortality in a large sample of Korean adults over a full range of uric acid levels.

METHODS

A cohort study was performed in 375,163 South Korean men and women who underwent health check-ups from 2002 to 2012. Vital status and cause of death were ascertained from the national death records. Hazard ratios (HRs) and 95% confidence intervals (95% CIs) for mortality outcomes were estimated using Cox proportional hazards regression analysis.

RESULTS

During a total of 2,060,721.9 person-years of follow-up, 2,020 participants died, with 287 CVD deaths and 963 cancer deaths. Low and high uric acid levels were associated with increased all-cause, CVD, and cancer mortality. The multivariable-adjusted HRs for all-cause mortality in the lowest uric acid categories (<3.5 mg/dl for men and <2.5 mg/dl for women) compared with the sex-specific reference category were 1.58 (95% CI 1.18-2.10) and 1.80 (95% CI 1.10-2.93), respectively. Corresponding HRs in the highest uric acid categories (≥9.5 mg/dl for men and ≥8.5 mg/dl for women) were 2.39 (95% CI 1.57-3.66) and 3.77 (95% CI 1.17-12.17), respectively.

CONCLUSION

In this large cohort study of men and women, both low and high uric acid levels were predictive of increased mortality, supporting a U-shaped association between serum uric acid levels and adverse health outcomes.

Diabetes mellitus and arthritis: is it a risk factor or comorbidity?: A systematic review and meta-analysis

BACKGROUND

Investigators have explored the association between diabetes mellitus and arthritis for a long time; however, there are uncertainties and inconsistencies among various studies. In this study, we tried to explore the relationship between diabetes mellitus and the overall risk of arthritis, as well as the potential modifiers for this relationship.

METHODS

We conducted a comprehensive literature search through PubMed and identified 36 eligible studies. The overall analyses, subgroup analyses, as well as sensitivity analyses, were conducted to illustrate the association between diabetes mellitus and arthritis. Study quality was evaluated using the Newcastle-Ottawa Quality Assessment Scale. All statistical analyses were conducted using STATA SE version 13.0.

RESULTS

In our study, 36 eligible studies were identified and involved in the meta-analysis. The overall association between diabetes mellitus and arthritis is 1.61 (95% confidence interval [CI]: 1.14-2.28, P = .007). The association exists only in nongouty arthritis, where we observed the estimated odds ratio (OR) 1.33 (95% CI: 1.05-1.67, P < .001). The opposite point estimates from different types of diabetes may indicate possible different associations for type I (OR: 0.98, 95% CI: 0.18-5.39, P = .985) or type II diabetes (OR: 1.28, 95% CI: 0.88-1.84, P = .194).

CONCLUSION

Diabetes mellitus performs more likely as a comorbidity of arthritis rather than a risk factor; however, more studies will be helpful to increase the confidence of identifying the association between diabetes and arthritis.

Serum Uric Acid and the Risk of Incident and Recurrent Gout: A Systematic Review

OBJECTIVE

Lowering serum uric acid (SUA) levels can essentially cure gout; however, this is not widely practiced. To summarize epidemiologic evidence related to this causal link, we conducted a systematic review of the published literature reporting the association between SUA level and incident and recurrent gout (i.e., gout flares).

METHODS

We systematically searched Medline, EMBASE, and the Cochrane Database of Systematic Reviews using separate search strategies for incident gout and recurrent gout. We screened 646 abstracts to identify 8 eligible articles reporting gout incidence and 913 abstracts to identify 18 articles reporting recurrent gout.

RESULTS

For both gout incidence and recurrence, a graded trend was observed where the risk was increased with higher SUA levels. Gout incidence rates per 1000 person-years from population-based studies ranged from 0.8 (SUA ≤ 6 mg/dl) to 70.2 cases (SUA ≥ 10 mg/dl). Recurrent gout risk in clinical cohorts ranged from 12% (SUA ≤ 6 mg/dl) to 61% (SUA ≥ 9 mg/dl) among those receiving urate-lowering therapy (ULT), and 3.7% (SUA 6-7 mg/dl) to 61% (SUA > 9.3 mg/dl) after successful ULT. Retrospective database studies also showed a graded relationship, although the strength of the association was weaker. Studies reporting mean flares or time-to-flare according to SUA showed similar findings.

CONCLUSION

This systematic review confirms that higher SUA levels are associated with increased risk of incident and recurrent gout in a graded manner. Although few prospective cohorts have evaluated incident and recurrent gout according to SUA, the existing evidence underscores the need to treat to SUA targets, as recommended by the American College of Rheumatology and the European League Against Rheumatism.

Lower serum uric acid level predicts mortality in dialysis patients

We evaluated the impact of serum uric acid (SUA) on mortality in patients with chronic dialysis. A total of 4132 adult patients on dialysis were enrolled prospectively between August 2008 and September 2014. Among them, we included 1738 patients who maintained dialysis for at least 3 months and had available SUA in the database. We categorized the time averaged-SUA (TA-SUA) into 5 groups: <5.5, 5.5-6.4, 6.5-7.4, 7.5-8.4, and ≥8.5 mg/dL. Cox regression analysis was used to calculate the hazard ratio (HR) of all-cause mortality according to SUA group. The mean TA-SUA level was slightly higher in men than in women. Patients with lower TA-SUA level tended to have lower body mass index (BMI), phosphorus, serum albumin level, higher proportion of diabetes mellitus (DM), and higher proportion of malnourishment on the subjective global assessment (SGA). During a median follow-up of 43.9 months, 206 patients died. Patients with the highest SUA had a similar risk to the middle 3 TA-SUA groups, but the lowest TA-SUA group had a significantly elevated HR for mortality. The lowest TA-SUA group was significantly associated with increased all-cause mortality (adjusted HR, 1.720; 95% confidence interval, 1.007-2.937; P = 0.047) even after adjusting for demographic, comorbid, nutritional covariables, and medication use that could affect SUA levels. This association was prominent in patients with well nourishment on the SGA, a preserved serum albumin level, a higher BMI, and concomitant DM although these parameters had no significant interaction in the TA-SUA-mortality relationship except DM. In conclusion, a lower TA-SUA level <5.5 mg/dL predicted all-cause mortality in patients with chronic dialysis.

Bidirectional Association between Diabetes and Gout: the Singapore Chinese Health Study

We aimed to prospectively investigate the bidirectional association between type 2 diabetes (T2D) and gout. We analyzed follow-up data from the Singapore Chinese Health Study, when self-reports of diagnosed diabetes and gout were enquired at follow-ups I and II. Individuals who participated in both follow-ups and were free of cardiovascular disease or cancer at follow-up I were included. For T2D to gout (analysis I), prevalent gout were further excluded (final n = 31,137). For gout to T2D (analysis II), prevalent diabetes were excluded (final n = 28,668). Cox regression models were used to estimate relative risks (RRs). In the analysis I, the RR of diabetes to incident gout (682 cases) was 0.77 (95% CI 0.60–0.97). In the analysis II, the RR of gout to incident diabetes (2223 cases) was 1.36 (1.12–1.63), but became insignificant after adjustment for hypertension and BMI (1.00; 0.83–1.21). The gout to diabetes association was modified by BMI (P_interaction = 0.04) and hypertension (P_interaction = 0.007), and it was marginally significant in adults with BMI<24 while significant among non-hypertensive participants, but not in their counterparts. In conclusion, our results suggest that diabetes is associated with a lower risk of incident gout, while gout is positively related to diabetes among normal weight and non-hypertensive adults.

Safety and efficacy of oral febuxostat for treatment of HLA-B*5801-negative gout: a randomized, open-label, multicentre, allopurinol-controlled study

Objectives: This phase IIIB study compared the efficacy and safety of febuxostat and allopurinol in gout patients with or without tophi who were HLA-B*5801 negative.

Method: Eligible patients were randomized to a febuxostat group (80 mg QD) or an allopurinol group (300 mg QD). Following an initial 2-week washout period, over the next 12 weeks we made five measurements of serum urate levels along with assessments of adverse events (AEs).

Results: Forty-three out of 152 screened subjects (28.3%) were ineligible either because of the presence of the HLA-B*5801 allele or for various other reasons. The febuxostat group (n = 54) and the allopurinol group (n = 55) had no significant differences in demographic or baseline characteristics. From week 2 to week 12, the febuxostat group had a significantly lower serum urate level than the allopurinol group (p ≤ 0.001 for all comparisons) and significantly more patients with serum urate levels less than 6.0 mg/dL. The serum urate levels of the febuxostat group declined by more than 40% from week 2 to week 12 and this decrease was greater than that in the allopurinol group (~30%). The two groups were similar in terms of AEs.

Conclusions: Febuxostat was more effective than allopurinol in reducing the serum urate levels of Han Chinese patients with gout or tophaceous gout who were HLA-B*5801 negative, without causing any serious skin reactions. Febuxostat should be considered for treatment of Han Chinese patients with gout who are HLA-B*5801 negative.

Effect of Urate-Lowering Therapy on All-Cause and Cardiovascular Mortality in Hyperuricemic Patients without Gout: A Case-Matched Cohort Study

Objectives

An increased risk of mortality in patients with hyperuricemia has been reported. We examined (1) the risk of all-cause and cardiovascular disease (CVD) mortality in untreated hyperuricemic patients who did not receive urate-lowering therapy (ULT), and (2) the impact of ULT on mortality risk in patients with hyperuricemia.

Methods

In this retrospective case-matched cohort study during a mean follow-up of 6.4 years, 40,118 Taiwanese individuals aged ≥17 years who had never used ULT and who had never had gout were examined. The mortality rate was compared between 3,088 hyperuricemic patients who did not receive ULT and reference subjects (no hyperuricemia, no gout, no ULT) matched for age and sex (1:3 hyperuricemic patients/reference subjects), and between 1,024 hyperuricemic patients who received ULT and 1,024 hyperuricemic patients who did not receive ULT (matched 1:1 based on their propensity score and the index date of ULT prescription). Cox proportional hazard modeling was used to estimate the respective risk of all-cause and CVD (ICD-9 code 390–459) mortality.

Results

After adjustment, hyperuricemic patients who did not receive ULT had increased risks of all-cause (hazard ratio, 1.24; 95% confidence interval, 0.97–1.59) and CVD (2.13; 1.34–3.39) mortality relative to the matched reference subjects. Hyperuricemic patients treated with ULT had a lower risk of all-cause death (0.60; 0.41–0.88) relative to hyperuricemic patients who did not receive ULT.

Conclusion

Under-treatment of hyperuricemia has serious negative consequences. Hyperuricemic patients who received ULT had potentially better survival than patients who did not.

An Independent Risk of Gout on the Development of Deep Vein Thrombosis and Pulmonary Embolism: A Nationwide, Population-Based Cohort Study

Previous studies indicated that gout is a risk factor of cardiovascular diseases. This study aimed to determine if patients with gout have an increased risk of deep vein thrombosis (DVT) or pulmonary embolism (PE).We used the Longitudinal Health Insurance Database, a subset of the national insurance claim dataset, which enrolled 1 million Taiwanese to identify 57,981 patients with gout and 115,961 reference subjects matched by sex, age, and entry date of diagnosis. The risk of DVT and PE was analyzed using the Cox proportional hazards model.In this Taiwanese dataset observed from 2000 to 2010, we found the incidence of DVT was 5.26 per 10 person-years in the gout cohort, which was twofold higher than the incidence of 2.63 per 10 person-years in the reference cohort. After adjusting for age, sex, and 9 comorbidities, the hazard ratio (HR) of developing DVT was 1.66 (95% confidence interval [CI] = 1.37-2.01). Among patients with gout, the youngest age group had the highest increase in the risk of developing DVT (HR [95% CI] = 2.04 [1.24-3.37] for ages 20 to 49 years, 1.80 [1.28-2.51] for ages 50 to 64 years, and 1.45 [1.11-1.91] for ages ≥65 years). The incidence of PE was about one-fifth that of DVT in gout patients, but the effect of gout on the risk was similar (HR [95% CI] = 1.53 [1.01-2.29]).Our analysis confirmed that gout increased the risk of DVT and PE. Further exploration is needed in the future.

Attenuating the mortality risk of high serum uric acid: the role of physical activity underused

BACKGROUND

High serum uric acid (sUA) has been associated with increased mortality risks, but its clinical treatment varied with potential side effects. The role of physical activity has received limited attention.

METHODS

A cohort, consisting of 467 976 adults, who went through a standard health screening programme, with questionnaire and fasting blood samples, was successively recruited between 1996 and 2008. High sUA is defined as uric acid above 7.0 mg/dL. Leisure time physical activity level was self-reported, with fully active defined as those with 30 min per day for at least 5 days a week. National death file identified 12 228 deaths with a median follow-up of 8.5 years. Cox proportional model was used to analyse HRs, and 12 variables were controlled, including medical history, life style and risk factors.

FINDINGS

High sUA constituted one quarter of the cohort (25.6%). Their all-cause mortality was significantly increased [HR: 1.22 (1.15-1.29)], with much of the increase contributed to by the inactive (HR: 1.27 (1.17-1.37)), relative to the reference group with sUA level of 5-6 mg/dL. When they were fully active, mortality risks did not increase, but decreased by 11% (HR: 0.89 (0.82-0.97)), reflecting the benefits of being active was able to overcome the adverse effects of high sUA. Given the same high sUA, a 4-6 years difference in life expectancy was found between the active and the inactive.

CONCLUSIONS

Physical activity is a valuable alternative to pharmacotherapy in its ability to reduce the increases in mortality risks from high sUA. By being fully active, exercise can extend life span by 4-6 years, a level greater than the 1-4 years of life-shortening effect from high sUA.