Significance of serum uric acid levels on the risk of all-cause and cardiovascular mortality

Association between annual changes and visit-to-visit variability of serum uric acid and the kidney outcome in a general population

BACKGROUND

To determine whether variability of serum uric acid (UA) is associated with risk of chronic kidney disease (CKD) in a healthy population.

METHODS

Retrospective, longitudinal cohort study was conducted at a health examination center in China. The study enrolled subjects who had a minimum of three visits between 2011 and 2018. We assessed UA change and visit-to-visit UA variability including standard deviation (SD), coefficient of variation (CV), variability independent of the mean (VIM), and average real variability (ARV). Rapid estimated glomerular filtration rate (eGFR) decline was defined by annual eGFR change < -4 mL/min/1.73 m2/year. We conducted a multivariable-adjusted logistic regression analysis.

RESULTS

Ten thousand seven hundred and thirty-eight participants were included. During 4.43 ± 1.31 years follow-up, there were 535 cases with rapid eGFR decline and 240 cases developed CKD. Compared to the non-rapid eGFR decline group and non-CKD group, the UA annual changes and variability were higher in the rapid eGFR decline group and CKD group. The highest quartile of UA annual changes and variability showed a higher incident rate of rapid eGFR decline and that of CKD. After adjusting for covariates, OR for eGFR rapid decline in UA variability were 1.69 [1.53, 1.86] for annual changes of UA, 1.17 [1.08, 1.27] for SD of UA, 1.16 [1.06, 1.25] for CV of UA, 1.16 [1.07, 1.25] for VIM of UA, and 1.10 [1.02, 1.19] for ARV of UA. Consistent results were observed when CKD is used as the outcome.

CONCLUSIONS

Higher variability of serum UA was independently associated with the risk of kidney impairment.

Effects of ertugliflozin on uric acid and gout-related outcomes in persons with type 2 diabetes and cardiovascular disease: Post hoc analyses from VERTIS CV

AIM

To conduct post hoc analyses of the VERTIS CV (NCT01986881) trial to explore the effects of ertugliflozin on serum uric acid (UA) and gout-related outcomes.

MATERIALS AND METHODS

Participants with type 2 diabetes and atherosclerotic cardiovascular disease were randomised (1:1:1) to placebo, ertugliflozin 5 mg or ertugliflozin 15 mg. Mean UA over time (260 weeks) was evaluated for pooled ertugliflozin versus placebo overall, and by baseline quintile of UA (≤4.3 mg/dL [≤255.8 µmol/L], >4.3-5.1 mg/dL [>255.8-303.4 µmol/L], >5.1-5.8 mg/dL [>303.4-345.0 µmol/L], >5.8-6.9 mg/dL [>345.0-410.4 µmol/L] and >6.9 mg/dL [>410.4 µmol/L]), glycated haemoglobin level, albuminuria status, estimated glomerular filtration rate and KDIGO (Kidney Disease: Improving Global Outcomes in Chronic Kidney Disease) risk category. The effect of ertugliflozin on a composite of gout onset or initiation of anti-gout medication was assessed.

RESULTS

The mean UA levels at baseline were 5.67 and 5.62 mg/dL in the placebo and ertugliflozin groups, respectively. Ertugliflozin reduced UA over Weeks 6-260 compared with placebo, with least squares mean (LSM) changes (95% confidence interval [CI]) from baseline at Week 260 of 0.07 mg/dL (-0.02, 0.15) and -0.19 mg/dL (-0.25, -0.13) in the placebo and pooled ertugliflozin groups, respectively. At Week 260, placebo-adjusted LSM change (95% CI) from baseline in UA was -0.26 mg/dL (-0.36, -0.16) with ertugliflozin. Ertugliflozin was associated with reductions in UA across baseline UA quintiles compared with placebo. The incidence of the composite of gout-related outcomes was 84/2539 (3.3%) for placebo and 133/5091 (2.6%) for ertugliflozin (hazard ratio for the composite 0.76 [95% CI 0.580, 1.002]).

CONCLUSIONS

Ertugliflozin was generally associated with lowering UA overall and across subgroups compared with placebo, and numerically reduced rates of gout-related outcome events.

Sex-specific associations between prolonged serum uric acid levels and risk of major adverse cardiovascular events

Background

While hyperuricemia has been correlated with cardiovascular (CV) diseases, further evidence is required to evaluate the implications of stable serum uric acid (sUA) levels, especially concerning low sUA. This study aimed to investigate prolonged stable sUA levels and CV events/mortality.

Methods

We conducted a retrospective cohort study at a medical center using electronic medical records linked with the national claims database. Patients with at least two sUA measurements, with intervals ranging from 6 months to 4 years, were included. The mean of the first two eligible sUA measurements were analyzed, stratified by sex. Outcomes of interest comprised major adverse cardiovascular events (MACE), heart failure hospitalization, CV and all-cause mortality.

Results

This study included 33,096 patients (follow-up: men 6.6 years, women 6.4 years). After multivariable adjustment, cubic spline models showed that long-term high sUA levels were consistently associated with a higher risk of MACE, heart failure hospitalization, CV and all-cause mortality. A U-shaped association was observed between sUA levels and all-cause mortality in both sexes and between sUA levels and CV mortality in women. The impact of sUA, especially lower levels, on CV events and mortality was more pronounced in women than in men.

Conclusion

Long-term high sUA levels are consistently associated with increased risk of CV events and mortality. A U-shaped association between sUA levels and all-cause mortality was observed in both men and women and was pronounced in women. The findings underscore the importance of considering sUA levels, especially in women, when assessing CV risk.

Associations between serum uric acid and breast cancer incidence: A systematic review and meta-analysis

BACKGROUND

Serum uric acid (SUA) may be involved in the development of cancer by inhibiting oxidative stress, but its relationship with breast cancer remains unclear.

MATERIALS AND METHODS

The PubMed, Embase, and Web of Science databases were searched systematically for studies on SUA levels in women with breast cancer and the effect of SUA levels on the risk of breast cancer. The Newcastle‒Ottawa Quality Assessment Scale (NOS) was used to assess the quality of all relevant studies included.

RESULTS

A total of 19 studies were included, including 75,827 women with breast cancer and 508,528 healthy controls. A meta-analysis found that SUA levels were negatively correlated with breast cancer risk in women (HR = 0.94, 95% CI: 0.89 - 0.99, p = 0.003). SUA levels in female breast cancer patients were not significantly different from those in healthy controls (SMD = 0.49, 95% CI = -0.09 - 1.08, p = 0.10), while SUA levels were increased in female breast cancer patients in articles published after 2010, SUA concentration detected by spectrophotometry, and non-Asian populations, regardless of menopausal state and treatment state.

CONCLUSION

High levels of SUA may reduce the risk of breast cancer in women, suggesting that SUA was a protective factor in women.

Association between serum uric acid and colorectal cancer risk in European population: a two-sample Mendelian randomization study

Objectives

This study aimed to explore the potential causal associations between serum uric acid (SUA) and the risk of colorectal cancer, colon cancer and rectal cancer.

Methods

Twenty-six SUA-related single nucleotide polymorphisms which were identified by a large meta-analysis of genome-wide association studies (GWASs) were used as instrumental variables in the two-sample Mendelian randomization (MR) study. Meta-analyses were used to synthesize the results of multiple GWASs which were extracted from the MRC Integrative Epidemiology Unit GWAS database for each type of cancer. The inverse variance weighted (IVW) method was used as the primary MR method to analyze the association between SUA and colorectal cancer risk. Several sensitivity analyses were performed to test the robustness of results.

Results

The IVW method showed that there were no causal relationships between SUA and the risk of colorectal cancer [odds ratio (OR): 1.0015; 95% confidence interval (CI): 0.9975-1.0056] and colon cancer (OR: 1.0015; 95% CI: 0.9974-1.0055). The SUA levels were negative correlated with rectal cancer risk (OR: 0.9984; 95% CI: 0.9971-0.9998). The similar results were observed in both males (OR: 0.9987; 95% CI: 0.9975-0.9998) and females (OR: 0.9985; 95% CI: 0.9971-0.9999). The sensitivity analyses suggested no evidence of heterogeneity or horizontal pleiotropy. The leave-one-out analyses showed that one SNP (rs1471633) significantly drove the causal effect of SUA on rectal cancer risk. The MR-Egger regression and weighted median both showed that there were no causal relationships between SUA and the risk of colorectal cancer and its subtypes.

Conclusion

Overall, there was no linear causal association between SUA and the risk of colorectal cancer. However, further research is needed to investigate the role of higher SUA levels such as hyperuricemia or gout in the occurrence of colorectal cancer.

The association of low serum uric acid with mortality in older people is modified by kidney function: National Health and Nutrition Examination Survey (NHANES) 1999-2018

BACKGROUND

In older individuals, the role of low serum uric acid (SUA) as risk factor for mortality is debated. We therefore studied whether SUA levels, particularly low SUA concentrations, are associated with all-cause and cardiovascular (CV) mortality in older population, and to clarify potential effect modification of kidney function.

METHODS

We identified 14,005 older people in National Health and Nutrition Examination Survey (NHANES) data from 1999 to 2018. SUA was measured only at baseline. The relationship between SUA and mortality was assessed using Cox proportional hazards models and restricted cubic spline Cox regression stratified by the estimated glomerular filtration rate (eGFR).

RESULTS

During mean 8.3 years of follow-up, 4852 all-cause death and 1602 CV death were recorded. A significant U-shaped association was observed between SUA with all-cause mortality, with the lowest risk concentration of 5.5 mg/dL. Comparing to the reference group (5 to 7 mg/dL), the HR of 2 to < 5 mg/dL group was 1.11 (1.03-1.21) and 1.14 (1.00-1.30). This relationship was more pronounced in participants with an eGFR ≥ 60 ml/min/1.73m2 (HR, 1.16; 95%CI, 1.06-1.28). This situation similarly occurred in Urine protein negative group (HR, 1.14; 95%CI, 1.04-1.25).

CONCLUSIONS

Low SUA concentrations are associated with an increased risk in all-cause and CV mortality among older participants. Extremely low SUA concentrations are especially undesirable, especially in the older adults with normal kidney function.

Novel pathological implications of serum uric acid with cardiovascular disease risk in obesity

AIMS

This cohort study intended to elucidate the association between serum uric acid (SUA) levels and cardiovascular disease events in Japanese patients with obesity.

METHODS

Altogether, 450 obese Japanese outpatients were enrolled in a multicenter prospective cohort Japan, the Japan Obesity and Metabolic Syndrome Study. Primary analysis regarding the measurements of cardiovascular risk factors, including SUA levels, and the occurrence of macrovascular complications was based on following the participants over a 5-year period.

RESULTS

Of the eligible patients, 335 (74.4%) were followed into the fifth year. During the study period, 15 coronary heart disease, 7 stroke, and 6 arteriosclerosis obliterans events occurred in 39 patients. The CVD incidence rate was 15.8 per 1000 person-years. In the analysis of adjusted models for traditional risk factors, hyperuricemia was a significant factor for the incidence of CVD events, especially in female obese patients. Additionally, we estimated the association between SUA levels and CVD events using cubic spline models, which showed a U-shaped association in both male and female patients.

CONCLUSIONS

SUA is an effective predictor of CVD events in female obese patients and a risk factor for CVD incident in obese patients.

The fructose survival hypothesis for obesity

The fructose survival hypothesis proposes that obesity and metabolic disorders may have developed from over-stimulation of an evolutionary-based biologic response (survival switch) that aims to protect animals in advance of crisis. The response is characterized by hunger, thirst, foraging, weight gain, fat accumulation, insulin resistance, systemic inflammation and increased blood pressure. The process is initiated by the ingestion of fructose or by stimulating endogenous fructose production via the polyol pathway. Unlike other nutrients, fructose reduces the active energy (adenosine triphosphate) in the cell, while blocking its regeneration from fat stores. This is mediated by intracellular uric acid, mitochondrial oxidative stress, the inhibition of AMP kinase and stimulation of vasopressin. Mitochondrial oxidative phosphorylation is suppressed, and glycolysis stimulated. While this response is aimed to be modest and short-lived, the response in humans is exaggerated due to gain of 'thrifty genes' coupled with a western diet rich in foods that contain or generate fructose. We propose excessive fructose metabolism not only explains obesity but the epidemics of diabetes, hypertension, non-alcoholic fatty liver disease, obesity-associated cancers, vascular and Alzheimer's dementia, and even ageing. Moreover, the hypothesis unites current hypotheses on obesity. Reducing activation and/or blocking this pathway and stimulating mitochondrial regeneration may benefit health-span. This article is part of a discussion meeting issue 'Causes of obesity: theories, conjectures and evidence (Part I)'.

Association of serum uric acid with risk of stroke in US adults: A cross-sectional study from NHANES 1999-2020

BACKGROUND AND AIMS

The validity of high uric acid levels as an independent cause of stroke remains controversial, and the association between its low concentration and stroke is unclear. This study determines how different serum uric acid (SUA) levels are associated with stroke risk.

METHODS

This cross-sectional study used continuous National Health and Nutrition Examination Survey data in the United States during 1999-2020. The SUA levels of 6.0, 6.8, and 9.0 mg/dL were all considered as cut-off points. Restricted cubic spline interpolation and logistic regression models were used to evaluate the different associations. Subgroup analyses and sensitivity analyses were conducted to evaluate the influence of multiple factors on the outcomes.

RESULTS

The study included 23,413 participants aged ≥ 20 years. A J-shaped curve existed between SUA and stroke risk, and the risk of stroke was positively correlated with SUA levels in the overall population. Subgroup analysis of all adults in the SUA 6.8-9.0 mg/dL group showed that stroke risk for non-Hispanic white, obese, ex-smoker, and heavy drinking groups was increased, but for the other Hispanic group was reduced. In the SUA < 6.0 mg/dL group, stroke risk for ex-smoker, heavy drinkers, and no chronic kidney disease groups was increased.

CONCLUSION

Our findings indicate a J-shaped relationship between SUA levels and stroke risk. Low and high SUA levels increased stroke risk for different populations, except in the other Hispanic population. Early SUA management is highly significant for stroke prevention in high-risk populations.

J-shaped association between uric acid and breast cancer risk: a prospective case-control study

BACKGROUND/AIM

In terms of breast cancer risk, there is no consensus on the effect of uric acid (UA) levels. The aim of our study was to clarify the link between UA and breast cancer risk in a prospective case-control study and to find the UA threshold point.

METHODS

We designed a case-control study with 1050 females (525 newly diagnosed breast cancer patients and 525 controls). We measured the UA levels at baseline and confirmed the incidence of breast cancer through postoperative pathology. We used binary logistic regression to study the association between breast cancer and UA. In addition, we performed restricted cubic splines to evaluate the potential nonlinear links between UA and breast cancer risk. We used threshold effect analysis to identify the UA cut-off point.

RESULTS

After adjusting for multiple confounding factors, we found that compared with the referential level (3.5-4.4 mg/dl), the odds ratio (OR) of breast cancer was 1.946 (95% CI 1.140-3.321) (P < 0.05) in the lowest UA level and 2.245 (95% CI 0.946-5.326) (P > 0.05) in the highest level. Using the restricted cubic bar diagram, we disclosed a J-shaped association between UA and breast cancer risk (P-nonlinear < 0.05) after adjusting for all confounders. In our study, 3.6 mg/dl was found to be the UA threshold which acted as the optimal turning point of the curve. The OR for breast cancer was 0.170 (95% CI 0.056-0.512) to the left and 1.283 (95% CI 1.074-1.532) to the right of 3.6 mg/dl UA (P for log likelihood ratio test < 0.05).

CONCLUSION

We found a J-shaped association between UA and breast cancer risk. Controlling the UA level around the threshold point of 3.6 mg/dl provides a novel insight into breast cancer prevention.

Positive correlation between fatty liver index and hyperuricemia in hypertensive Chinese adults: a H-type hypertension registry study

Background

Few studies have examined the relationship between fatty liver index (FLI) and hyperuricemia (HUA). This study explores the relationship between FLI and HUA in hypertensive patients.

Methods

A total of 13,716 hypertensive subjects were included in the current study. FLI, a simple index calculated from triglycerides (TG), waist circumference (WC), body mass index (BMI), and γ -glutamyltransferase (GGT), was used as a useful predictor of nonalcoholic fatty liver disease (NAFLD) distribution. HUA was defined as serum uric acid ≥ 360 μmol/L for females and ≥ 420 μmol/L for males.

Results

The mean value of total FLI was 31.8 ± 25.1. Multiple logistic analyses revealed a significant positive correlation between FLI and HUA (OR, 1.78; 95% CI: 1.69-1.87). A subgroup analysis demonstrated that the correlation between FLI (< 30 vs. ≥ 30) and HUA was significant in both sexes (P for interaction = 0.006). Further analyses stratified by sex indicated a positive correlation between FLI and HUA prevalence among male and female subjects. However, the correlation between FLI and HUA was stronger in female subjects than in males (male: OR, 1.70; 95% CI: 1.58-1.83; female: 1.85; 95% CI: 1.73-1.98).

Conclusion

This study demonstrates a positive correlation between FLI and HUA in hypertensive adults, but stronger in females than males.

Serum uric acid variation and the risk of cardiovascular disease: A prospective cohort study

BACKGROUND

The association of serum uric acid (SUA) with cardiovascular disease (CVD) is inconsistent and limited by a single measurement of SUA. This study aimed to investigate the association of SUA variation, considering its magnitude and direction, with the risk of CVD.

METHODS

This study included 41,578 participants with four biennial measurements of SUA during 2006-2012 from the Kailuan study. SUA variation was measured using the coefficient of variation (primary index), standard deviation, average real variability, and variability independent of mean, and the direction of variation was also assessed. Multivariate-adjusted Cox regressions were used to assess the associations, and Bayesian network was utilized to find the most important pathway from SUA variation to CVD.

RESULTS

During a median follow-up of 6.74 (interquartile range: 6.45-7.03) years, we identified 1,852 (4.45%) cases of incident CVD. A large SUA variation (top vs. bottom tertiles) was associated with a higher risk of CVD (hazard ratio [HR], 1.24; 95% confidence interval [CI], 1.11-1.40), especially in older adults than that in young adults (Pint=0.0137). The higher risk of CVD was observed with both large rises (HR, 1.24; 95% CI, 1.10-1.39) and falls (HR, 1.19; 95% CI, 1.03-1.38) in SUA variation. The hazardous effect of SUA variation on CVD was mainly induced by excessive inflammation and elevated blood pressure. Similar results were observed for CVD subtypes.

CONCLUSIONS

Elevated SUA variation was associated with a higher risk of CVD, irrespective of the direction of SUA variation, and inflammation played an important role in the pathway.

Sex differences between serum uric acid levels and cardiovascular outcomes in patients with coronary artery disease after stent implantation

Background

The relationship between elevated serum uric acid (SUA) levels and cardiovascular outcomes after stent implantation remains uncertain. This study sought to evaluate the impact of SUA on 12-month cardiovascular outcomes after stent implantation.

Methods

We performed a retrospective study of patients who successfully underwent stent implantation and enrolled 3,222 patients with coronary artery disease (CAD) from a single center. SUA levels were measured before stent implantation. The patients were divided into six groups (<4, 4-4.9, 5-5.9, 6-6.9, 7-7.9 and ≥ 8 mg/dL) at SUA intervals of 1.0 mg/dL. The incidence of cardiovascular outcomes in the six groups was monitored for 1 year after stent implantation and the hazard ratios were estimated. Hazard ratios (HRs) and 95% confidence intervals (95% CIs) for cardiovascular outcomes were estimated using a Cox proportional hazard regression analysis. The primary endpoint was all-cause death. The secondary endpoint was a composite of all-cause death, myocardial infarction, target vessel revascularization, stent thrombosis and stroke. The follow-up duration was 12 months.

Results

Over the 12-month follow-up period, there were 101 all-cause deaths and 218 MACCE. After adjustment for several parameters, the group with SUA levels of more than or equal to 8 mg/dL had significantly higher hazard ratios in the incidence of all-cause death or MACCE. The group with <4.0 mg/dL had significantly higher hazard ratios in all-cause death only in male patients. In contrast, there were no significant differences observed for cardiovascular outcomes in female patients.

Conclusions

Our study identified a U-shaped association between SUA levels and cardiovascular outcomes during 12-month follow-up for males, but not for females. Further studies are warranted to clarify the sex differences between SUA levels and clinical outcomes.

Change in Serum Uric Acid is a Useful Predictor of All-Cause Mortality among Community-Dwelling Persons

There is limited research on the association between longitudinal variability in serum uric acid (SUA) and all-cause mortality in the general population, although recent studies have suggested that changes in SUA are associated with all-cause mortality in adults. This study aims to examine the association between percentage change in SUA (%dSUA = 100 × (cohort 2 SUA - cohort 1 SUA)/(time × cohort 1 SUA) and all-cause mortality. This study is based on 1,301 participants, of whom 543 were male (63 ± 11 years) and 758 were female (63 ± 9 years). We obtained adjusted relative risk estimates for all-cause mortality and used a Cox proportional hazards model, adjusted for possible confounders, to determine the hazard ratio (HR) and 95% confidence interval (CI) of %dSUA. Of all the participants, 79 (6.1%) were deceased, and of these, 45 were male (8.3%) and 34 were female (4.5%). The multivariable-adjusted HRs (95% CI) for all-cause mortality for the first, second to fourth (reference), and fifth %dSUA quintiles were 3.79 (1.67-8.48), 1.00, and 0.87 (0.29-2.61) for male participants and 4.00 (1.43-11.2), 1.00, and 1.19 (0.46-3.05) for female participants, respectively. Participants with a body mass index of <22 kg/m² had a significantly higher HR, forming a U-shaped curve for the first (HR, 7.59; 95% CI, 2.13-27.0) and fifth quintiles (HR, 2.93; 95% CI, 1.05-8.18) relative to the reference. Percentage change in SUA is independently and significantly associated with future all-cause mortality among community-dwelling persons.

Gender-Specific and U-Shaped Relationship Between Serum Uric Acid and All-Cause Mortality Among Chinese Older Adults: A National Population-Based Longitudinal Study

Objectives: This study aimed to prospectively investigate gender-specific relationship between hyperuricemia and all-cause mortality among Chinese older adults. Methods: The study was based on the Chinese Longitudinal Healthy Longevity Survey (CLHLS) 2008-2018, a prospective nationwide cohort of older adults in China. Multivariate Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% CIs for all-cause mortality. Restricted cubic splines (RCS) were conducted to explore the dose-response relationship between SUA levels and all-cause mortality. Results: For older women, compared to the participants in the third quartile of SUA level, those in the highest quartile of SUA was associated with significantly higher risk of all-cause mortality in the fully adjusted model (HR: 1.41, 95% CI: 1.03-1.92). No significant associations between SUA levels and all-cause mortality were observed in older men. The present study further found a U-shaped non-linear relationship between SUA levels and all-cause mortality in both sexes of older population (P for non-linear <0.05). Conclusions: This study provided prospective epidemiological evidence for the predictive role of SUA on all-cause mortality among the Chinese aging population over 10 years of follow-up, while revealing considerable gender-related differences.

Prediction of Postoperative Pathologic Risk Factors in Cervical Cancer Patients Treated with Radical Hysterectomy by Machine Learning

Pretherapeutic serological parameters play a predictive role in pathologic risk factors (PRF), which correlate with treatment and prognosis in cervical cancer (CC). However, the method of pre-operative prediction to PRF is limited and the clinical availability of machine learning methods remains unknown in CC. Overall, 1260 early-stage CC patients treated with radical hysterectomy (RH) were randomly split into training and test cohorts. Six machine learning classifiers, including Gradient Boosting Machine, Support Vector Machine with Gaussian kernel, Random Forest, Conditional Random Forest, Naive Bayes, and Elastic Net, were used to derive diagnostic information from nine clinical factors and 75 parameters readily available from pretreatment peripheral blood tests. The best results were obtained by RF in deep stromal infiltration prediction with an accuracy of 70.8% and AUC of 0.767. The highest accuracy and AUC for predicting lymphatic metastasis with Cforest were 64.3% and 0.620, respectively. The highest accuracy of prediction for lymphavascular space invasion with EN was 59.7% and the AUC was 0.628. Blood markers, including D-dimer and uric acid, were associated with PRF. Machine learning methods can provide critical diagnostic prediction on PRF in CC before surgical intervention. The use of predictive algorithms may facilitate individualized treatment options through diagnostic stratification.

Uric Acid and Chronic Kidney Disease: Still More to Do

Gout and hyperuricemia are present in 25% and 60% of patients with chronic kidney disease (CKD), respectively. Despite the common association, the role of uric acid in the progression of kidney disease and in metabolic complications remains contested. Some authorities argue that the treatment of asymptomatic hyperuricemia in CKD is not indicated, and some have even suggested hyperuricemia may be beneficial. Here, we review the various arguments both for and against treatment. The weight of the evidence suggests asymptomatic hyperuricemia is likely injurious, but it may primarily relate to subgroups, those who have systemic crystal deposits, those with frequent urinary crystalluria or kidney stones, and those with high intracellular uric acid levels. We recommend carefully designed clinical trials to test if lowering uric acid in hyperuricemic subjects with cardiometabolic complications is protective.

The effect of serum uric acid concentration on the severity of chronic congestive heart failure

This study aimed to investigate the adverse effects of serum uric acid concentration on the severity of chronic congestive heart failure. One hundred patients with chronic congestive heart failure (several risk factors include hypertension, smoking, and diabetes mellitus) were enrolled in this study (51 females and 49 males). Participants were admitted to Alsader Medical City in Al-Najaf from August 2018 to March 2019. Detailed medical history and complete clinical examination were performed for all patients. The patients' ages ranged from 13-90 years, with a mean of 62.1±15.8 years, and the median was 65 years. No statistically significant age difference was observed between males and females (P-value=0.687). Increased serum uric acid had a directly negative effect on the severity of chronic congestive heart failure and hypertension. High serum uric acid concentration was associated with increased severity of chronic congestive heart failure class NYHA III and NYHA IV and a decrement in ejection fraction of the left ventricle.

Do thrifty genes exist? Revisiting uricase

Sixty years ago, the geneticist James Neel proposed that the epidemics of obesity and diabetes today may have evolutionary roots. Specifically, he suggested that our ancestors may have accumulated mutations during periods of famine that provided a survival advantage at that time. However, the presence of this "thrifty genotype" in today's world, where food is plentiful, would predispose us to obesity and diabetes. The "thrifty gene" hypothesis, attractive to some, has been challenged over the years. The authors have previously postulated that the loss of the uricase gene, resulting in a rise in serum and intracellular uric acid levels, satisfies the criteria of a thrifty genotype mutation. This paper reviews and brings up-to-date the evidence supporting the hypothesis and discusses the current arguments that challenge this hypothesis. Although further studies are needed to test the hypothesis, the evidence supporting a loss of uricase as a thrifty gene is substantial and supports a role for evolutionary biology in the pathogenesis of the current obesity and diabetes epidemics.

Association of serum uric acid levels with cardiovascular and all-cause mortality in hypertensive patients in China: a cohort study

Purpose

The present study aimed to assess the association of elevated serum uric acid (SUA) and hypouricemia with all-cause mortality and cardiovascular mortality in Chinese hypertensive patients.

Methods

In the present prospective cohort, 9325 hypertensive patients from Dongguan, China were enrolled from 2014 to 2018 for analysis. Participants were categorised by quintiles of SUA. The HRs and 95% CIs for the association between SUA, all-cause and cardiovascular mortality were evaluated using the multivariate Cox regression model. After adjusting for multiple confounders, restricted cubic spline analysis was conducted to demonstrate the shape of relationship.

Results

After a median follow-up of 4.18 years for 9325 participants, there were 409 (4.4%) and 151 (1.6%) reported cases of all-cause and cardiovascular mortality, respectively. By using the third quintile of SUA (6.68 mg/dL to <7.55 mg/dL for men, 5.63 mg/dL to <6.42 mg/dL for women) as reference, the highest quintiles of SUA were associated with an elevated risk of all cause (HR: 1.34, 95% CI 1.00 to 1.80) in the crude model, but the association was not significant after adjusting for multiple comparisons. The association between low SUA and mortality and the dose–response analysis on the non-linearity of SUA–mortality relationship were not statistically significant.

Conclusions

Although the association between SUA levels, all-cause and cardiovascular disease mortality did not appear to be significant among Chinese hypertensive patients, the findings might be confounded by their medical conditions. Further studies are needed to verify the optimal SUA levels for hypertensive patients.

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.

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

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

The U-Shaped Relationship Between Serum Uric Acid and Long-Term All-Cause Mortality in Coronary Artery Disease Patients: A Cohort Study of 33,034 Patients

Background

Associations between high serum uric acid (SUA) and cardiovascular diseases have been reported. However, few studies have been conducted to explore the relationship between SUA and long-term all-cause mortality in coronary artery disease (CAD) patients. Our study aims to investigate the relationship between SUA and long-term all-cause mortality in patients with CAD.

Methods

From January 2007 to December 2018, we divided 33,034 patients with CAD admitted in the Guangdong Provincial People's Hospital into five groups (quintile 1: SUA <5.05 mg/dl, quintile 2: 5.05 mg/dl ≤ SUA <5.59 mg/dl, quintile 3:5.59 mg/dl ≤ SUA <6.8 mg/dl, quintile 4, 6.8 mg/dl ≤ SUA <7.93 mg/dl, and quintile 5, SUA ≥7.93 mg/d;). This study used Kaplan–Meier survival analysis to evaluate patient outcomes with different ranges of SUA. Cox proportional hazards regression models and restricted cubic spline were applied to determine the association between serum uric and long-term all-cause mortality.

Results

A total of 33,034 participants were recruited, including 24,780 (75.01%) men and 8,254 (24.99) women in this cohort study. Median follow-up was 4.91 years. We found that SUA is an independent risk factor of long-term all-cause mortality according to the result of Cox proportional hazards models. This study also illustrated an approximate U-shape association between SUA and all-cause mortality when compared with 5.95 mg/lL ≤ SUA <6.8 mg/dl, SUA <5.0 5mg/dl (adjusted hazard ratio (aHR) =1.13, 95% CI: 1.01–1.26, p = 0.03), and SUA ≥8 mg/dL (aHR = 1.18, 95% CI: 1.06-1.32, p = 0.003).

Conclusion

Our study indicated a U-shaped relationship between SUA and long-term all-cause mortality in patients with CAD. No matter whether SUA is too high or too low, it increased the all-cause mortality in the CAD population, which deserves to be closely monitored.

Hyperuricemia is associated with all-cause mortality among males and females: Findings from a study on Japanese community-dwelling individuals

Background

Serum uric acid (SUA) is a key determinant of cardiovascular diseases (CVDs). Studies have also shown that SUA independently impacts age-related health outcomes, although their findings differ between males and females. Furthermore, predictive data on all-cause mortality remain limited, particularly for the Japanese population. Thus, this study examined the association between SUA and survival prognosis among males and females based on a follow-up period of 7 or 19 years.

Methods

The study was based on 1,573 male (63 ± 14 years) and 1,980 female (65 ± 12 years) participants who participated in a Nomura Cohort Study in 2002 (Cohort 1) and 2014 (Cohort 2), and continued throughout the follow-up period. A basic resident register was referenced to derive the adjusted relative risk estimates for all-cause mortality. Finally, a Cox proportional hazards model analysis was conducted and was adjusted for possible confounders to estimate hazard ratios (HRs). 95% confidence intervals (CIs) were computed separately for male and female participants.

Results

Of the total 3,553 participants, 905 (25.5%) were deceased. Of these, 473 were male (30.1% of all males) and 432 were female (21.8% of all females). Hyperuricemia was defined in males with SUA levels of 8.5 mg/dL or higher, and in females with SUA levels of 7.5 mg/dL or higher, and was associated with a significantly increased HR for all-cause mortality (males: 1.67; 95% CI: 1.06-2.63; females: 2.17; 95% CI: 1.20-3.94). The data were further stratified based on age (< 65 years or ≥ 65 years), body mass index (BMI) (< 25.0 kg/m2 or ≥ 25.0 kg/m2), History of cardiovascular disease, estimated glomerular filtration rate (< 60 mL/min/1.73 m2 or ≥ 60 mL/min/1.73 m2), and presence of SUA-lowering medication. All stratified groups demonstrated a similar trend. The hyperuricemia group in particular reported a significant increase in HR. On the other hand, a U-shaped increase in HR was observed in those with BMI greater than 25 kg/m2 and SUA-lowering medication, but interaction effect was not significant.

Conclusions

Hyperuricemia is a key risk indicator for all-cause mortality in male and female community-dwelling individuals in Japan.

Hypouricemia and Urate Transporters

Hypouricemia is recognized as a rare disorder, defined as a serum uric acid level of 2.0 mg/dL or less. Hypouricemia is divided into an overexcretion type and an underproduction type. The former typical disease is xanthinuria, and the latter is renal hypouricemia (RHUC). The frequency of nephrogenic hypouricemia due to a deficiency of URAT1 is high in Japan, accounting for most asymptomatic and persistent cases of hypouricemia. RHUC results in a high risk of exercise-induced acute kidney injury and urolithiasis. It is vital to promote research on RHUC, as this will lead not only to the elucidation of its pathophysiology but also to the development of new treatments for gout and hyperuricemia.

Cancer risk in Korean patients with gout

BACKGROUND/AIMS

Using a nationwide cohort, we investigated the cancer risk in Korean patients with gout.

METHODS

Data were obtained from the Korean National Health Insurance Service Database. Patients with gout were defined as those aged ≥ 20 years who were diagnosed with gout and received anti-gout medication (allopurinol, colchicine, and benzbromarone) between 2008 and 2010. Patients with nail disorders were randomly assigned to a control group (1:1 ratio) after frequency matching for age and sex. Cancer incidence was then investigated between 2012 and 2018. Cox proportional hazard regression analysis was used to investigate the association between gout and cancer after adjusting for concomitant diseases.

RESULTS

This study included 179,930 patients with gout and an equal number of matched controls. The incidence of overall cancer was higher in patients with gout than in controls (incidence rate ratio, 1.08). Cox proportional hazards regression analysis showed that gout was associated with a hazard ratio of 1.053 (95% confidence interval ,1.031 to 1.077) after adjusting for concomitant diseases.

CONCLUSION

Gout was associated with a significantly high risk of cancer, especially esophageal, stomach, colon, liver, pancreatic, lung, ovarian, renal, and bladder cancers.

Impact of serum uric acid levels on cardiovascular events and quality of life in patients with chronic coronary syndromes: Insights from a contemporary, prospective, nationwide registry

BACKGROUND AND AIMS

Hyperuricemia is a metabolic disorder that has been associated with adverse cardiovascular (CV) events. Using the data from a nationwide, prospective registry on patients with chronic coronary syndromes (CCS), we assessed the impact of serum uric acid (SUA) levels on quality of life (QoL) and major adverse CV events (MACE), a composite of CV death and hospitalization for myocardial infarction, heart failure (HF), angina or revascularization at 1-year.

METHODS AND RESULTS

Among the 5070 consecutive CCS patients enrolled in the registry, levels of SUA were available for 2394 (47.2%). Patients with SUA levels available at baseline were grouped as low tertile (n = 860; 4.3 [3.7-4.7] mg/dL), middle tertile (n = 739; 5.6 [5.3-5.9] mg/dL) and high tertile (n = 795; 7.1 [6.7-7.9] mg/dL). At 1 year, the incidence of MACE was 3.7%, 4.1% and 6.8% for low, middle and high tertiles, respectively (p = 0.005 for low vs high tertile). Patients in the high tertile of SUA had a significantly higher rate of CV mortality (1.4% vs 0.4%; p = 0.05) and hospital admission for HF (2.8% vs 1.6%; p = 0.03) compared to the low tertile. However, hyperuricemia did not result as an independent predictor of MACE at multivariable analysis [hazard ratio: 1.27; 95% confidence intervals: 0.81-2.00; p = 0.3].

CONCLUSIONS

In this contemporary, large cohort of CCS, those in the high tertile of SUA had a greater burden of CV disease and worse QoL. However, SUA did not significantly influence the higher rate of CV mortality, hospitalization for HF and MACE observed in these patients during 1-year follow-up.

Uric Acid and Clinical Outcomes in Young Patients with Ischemic Stroke

BACKGROUND AND PURPOSE

There is limited available evidence for the relationship between uric acid (UA) levels and ischemic stroke in young adults. We aimed to explore the association between UA levels and acute ischemic stroke (AIS) in young patients.

MATERIALS AND METHODS

This was a prospective and observational study. We recruited young patients aged 18-45 years with AIS at our tertiary hospital. Patients were categorized into four groups according to quartiles of UA levels. The primary outcome was functional outcome at 3 months. The secondary outcomes included stroke severity, in-hospital complications, and functional outcome at discharge. Modified Rankin Scale (mRS) scores were used to assess functional outcome as poor (mRS=2-6) or favorable(mRS=0-1).

RESULTS

A total of 636 patients were enrolled in the current analysis. The four groups were defined as follows: Q1≤289.8 µmol/L, 289.8 µmol/ L<Q2≤349.0 µmol/L, 349.0 µmol/L<Q3≤421 µmol/L, and Q4>421 µmol/L. Multiple logistic regression analysis showed that UA levels were not significantly predictive of functional outcome either at discharge or at 3 months after AIS. However, compared to Q1, higher UA levels were significantly negatively associated with the rate of moderate-severe stroke (NIHSS≥5) at admission (p for trend =0.016). Furthermore, a reduction in the risk for in-hospital pneumonia was significantly associated with higher UA levels compared to Q1 (P for trend < 0.0001).

CONCLUSION

Serum UA was a protective factor for stroke severity and in-hospital pneumonia after AIS in young patients. However, we were unable to identify the predictive significance of UA for functional outcome either at discharge or at 3 months after AIS.

Prevalence, patterns and predictors of metabolic abnormalities in Nigerian hypertensives with hypertriglyceridemic waist phenotype: A cross sectional study

BACKGROUND

Simultaneous presence of elevated waist circumference and hypertriglyceridemia (HTGW) is a simple and low-cost measure of visceral obesity, and it is associated with a plethora of cardio-metabolic abnormalities that can increase the risk of cardiovascular diseases and incident Type 2 diabetes mellitus. We decided to study the prevalence, patterns, and predictors of metabolic abnormalities in Nigerian hypertensives with the HTGW phenotype.

METHODS

The medical records of 582 hypertensives with complete data of interest were retrieved and analyzed for the study. Their socio-demographic data, anthropometric data, and booking blood pressure values were retrieved. The results of their fasting plasma glucose, lipid profile, uric acid and serum creatinine were also retrieved for analysis.

RESULTS

The mean age of the study population was 56.2 ±13.6, with 53.1% being males. The prevalence of smoking and use of alcohol was 4.3% and 26.5% respectively. The prevalence of the HTGW phenotype was 23.4% and were predominantly males (61%). Subjects with the HTGW phenotype were more obese assessed by waist circumference (WC) and body mass index (BMI). Mean serum total cholesterol, triglyceride, very low-density lipoprotein, uric acid, and creatinine were significantly higher in the HTGW phenotype (p = 0.003; <0.001; <0.001; 0.002 and <0.001 respectively). The prevalence of newly diagnosed Type 2 diabetes was 28.7%. There was also a preponderance of cardio-metabolic abnormalities (obesity, dyslipidaemia, hyperuricemia) in the HTGW phenotype. In both males and females, the HGTW phenotype was significantly associated with elevated Tc, TG, VLDL, hyperuricemia and atherogenic index of plasma.

CONCLUSION

The HTGW phenotype is common amongst Nigerian hypertensives, and it is associated with metabolic abnormalities.

Diagnostic model for predicting hyperuricemia based on alterations of the gut microbiome in individuals with different serum uric acid levels

BACKGROUND

We aimed to assess the differences in the gut microbiome among participants with different uric acid levels (hyperuricemia [HUA] patients, low serum uric acid [LSU] patients, and controls with normal levels) and to develop a model to predict HUA based on microbial biomarkers.

METHODS

We sequenced the V3-V4 variable region of the 16S rDNA gene in 168 fecal samples from HUA patients (n=50), LSU patients (n=61), and controls (n=57). We then analyzed the differences in the gut microbiome between these groups. To identify gut microbial biomarkers, the 107 HUA patients and controls were randomly divided (2:1) into development and validation groups and 10-fold cross-validation of a random forest model was performed. We then established three diagnostic models: a clinical model, microbial biomarker model, and combined model.

RESULTS

The gut microbial α diversity, in terms of the Shannon and Simpson indices, was decreased in LSU and HUA patients compared to controls, but only the decreases in the HUA group were significant (P=0.0029 and P=0.013, respectively). The phylum Proteobacteria (P<0.001) and genus Bacteroides (P=0.02) were significantly increased in HUA patients compared to controls, while the genus Ruminococcaceae_Ruminococcus was decreased (P=0.02). Twelve microbial biomarkers were identified. The area under the curve (AUC) for these biomarkers in the development group was 84.9% (P<0.001). Notably, an AUC of 89.1% (P<0.001) was achieved by combining the microbial biomarkers and clinical factors.

CONCLUSIONS

The combined model is a reliable tool for predicting HUA and could be used to assist in the clinical evaluation of patients and prevention of HUA.

Optimal uric acid levels by febuxostat treatment and cerebral, cardiorenovascular risks: post hoc analysis of a randomised controlled trial

OBJECTIVES

Hyperuricaemia is recognised as an independent risk marker for cardiovascular and renal diseases. However, uric acid is a powerful free-radical scavenger, and the optimal level of serum uric acid (SUA) determining outcomes are unknown. This study explored whether interventional treatments for excessive SUA reduction were harmful and what constituted the optimal lowering of SUA levels for the prevention of events in patients with asymptomatic hyperuricaemia.

METHODS

This was a post hoc analysis of a randomised trial (Febuxostat for Cerebral and CaRdiorenovascular Events PrEvEntion StuDy [FREED]) in which 1070 older patients with asymptomatic hyperuricaemia were enrolled and allocated to febuxostat (n = 537) or non-febuxostat treatment group (n = 533). We assessed the relationship between the end point (withdrawal or study completion) SUA levels and clinical outcomes. Primary end point was defined as a composite of all-cause mortality, cerebral and cardiorenovascular events.

RESULTS

In the febuxostat group, patients achieving SUA levels ≤4 mg/dl (hazard ratio: 2.01 [95% confidence interval: 1.05-3.87]), >4 to ≤ 5 mg/dl (2.12 [1.07-4.20], >6 to ≤ 7 mg/dl (2.42 [1.05-5.60]), and >7 mg/dl (4.73 [2.13-10.5]) had significantly higher risks for a primary composite event than those achieving SUA levels >5 to ≤ 6 mg/dl (p= 0.003 [log-rank test]). This J-shaped relationship applied to patients with renal impairment (p= 0.007 [Gray's test]) and was not significant in the non-febuxostat treatment group (p= 0.212 [log-rank test]).

CONCLUSION

Optimal SUA levels by febuxostat treatment is 5-6 mg/dl for reducing all-cause mortality, cerebral, cardiovascular, and renal events. Excessive SUA reduction may be harmful in older hyperuricaemic populations.

TRIAL REGISTRATION

ClinicalTrial.gov, https://clinicaltrials.gov, NCT01984749.

High serum uric acid may associate with the increased risk of colorectal cancer in females: A prospective cohort study

Elevated serum uric acid (SUA) levels have been previously reported to play a role in multiple types of cancers. However, epidemiological studies evaluating SUA levels and colorectal cancer risk remain sparse. This cohort study included 444 462 participants between the ages of 40 and 69 years from the UK Biobank, followed up from 2006 to 2010. Multivariable adjusted Cox regression models were used to estimate hazard ratios (HRs). During a mean follow-up of 6.6 years, 2033 and 855 cases of colon and rectal cancers, respectively, were diagnosed. The multivariable-adjusted HRs for risks of colon cancer in the lowest uric acid categories (≤3.5 mg/dL) compared with the reference groups were 1.31 (95% confidence interval [CI] = 0.75-2.29) in males and 1.26 (95% CI = 1.03-1.55) in females. The HRs in the highest uric acid groups (>8.4 mg/dL) were 1.16 (95% CI = 0.83-1.63) in males and 2.00 (95% CI = 1.02-3.92) in females. The corresponding HRs of rectal cancer in the lowest uric acid groups compared with the reference group were 2.21 (95% CI = 1.15-4.23) in males and 0.98 (95% CI = 0.66-1.45) in females. The HRs in the highest uric acid groups were 1.35 (95% CI = 0.82-2.23) in males and 3.81 (95% CI = 1.38-10.56) in females. In conclusion, SUA showed a U-shaped association with colon cancer risk in both male and female populations. The same pattern was observed in male patients with rectal cancer. However, SUA levels were positively associated with occurrence of rectal cancer in female subjects.

Variation in serum urate levels in the absence of gout and urate lowering therapy

BACKGROUND

Previous studies have noted significant variation in serum urate (sUA) levels, and it is unknown how this influences the accuracy of hyperuricemia classification based on single data points. Despite this known variability, hyperuricemic patients are often used as a control group in gout studies. Our objective was to determine the accuracy of hyperuricemia classifications based on single data points versus multiple data points given the degree of variability observed with serial measurements of sUA.

METHODS

Data was analyzed from a cross-over clinical trial of urate-lowering therapy in young adults without a gout diagnosis. In the control phase, sUA levels used for this analysis were collected at 2-4 week intervals. Mean coefficient of variation for sUA was determined, as were rates of conversion between normouricemia (sUA ≤6.8 mg/dL) and hyperuricemia (sUA > 6.8 mg/dL).

RESULTS

Mean study participant (n = 85) age was 27.8 ± 7.0 years, with 39% female participants and 41% African-American participants. Mean sUA coefficient of variation was 8.5% ± 4.9% (1 to 23%). There was no significant difference in variation between men and women, or between participants initially normouricemic and those who were initially hyperuricemic. Among those initially normouricemic (n = 72), 21% converted to hyperuricemia during at least one subsequent measurement. The subgroup with initial sUA < 6.0 (n = 54) was much less likely to have future values in the range of hyperuricemia compared to the group with screening sUA values between 6.0-6.8 (n = 18) (7% vs 39%, p = 0.0037). Of the participants initially hyperuricemic (n = 13), 46% were later normouricemic during at least one measurement.

CONCLUSION

Single sUA measurements were unreliable in hyperuricemia classification due to spontaneous variation. Knowing this, if a single measurement must be used in classification, it is worth noting that those with an sUA of < 6.0 mg/dL were less likely to demonstrate future hyperuricemic measurements and this could be considered a safer threshold to rule out intermittent hyperuricemia based on a single measurement point.

TRIAL REGISTRATION

Data from parent study ClinicalTrials.gov Identifier: NCT02038179 .

Relationship between serum uric acid levels and the incidence of cardiovascular events after percutaneous coronary intervention

BACKGROUND

The role of serum uric acid (SUA) as an independent risk factor for coronary artery disease remains unclear. The aim of this study was to investigate whether the SUA levels could affect the incidence of major adverse cardiac events (MACE) after percutaneous coronary intervention (PCI).

METHODS AND RESULTS

We retrospectively examined the clinical records of 1,949 patients who underwent successful PCI. First, they were divided into two groups based on an SUA level of 7.0mg/dl. Among the two groups, the incidence of MACE was measured for a maximum of 5 years after PCI. Next, we divided them into 6 groups at SUA intervals of 1.0mg/dl and estimated the hazard ratios of each group. The Kaplan-Meier curve demonstrated that patients with SUA levels of >7.0mg/dl had a higher incidence of MACE than those with 7.0mg/dl or less. However, according to the multivariate analysis, the SUA level was not significantly correlated with the incidence of MACE because other factors could strongly affect it. Meanwhile, the group with SUA levels between 4.1-5.0mg/dl had a lower hazard ratio compared to groups with SUA levels of more than 5.1mg/dl. However, the hazard ratio of the group with SUA levels of 4.0mg or less was not lower than that of the group with SUA levels of 4.1-5.0mg/dl. Even after adjustment for several parameters, nearly the same results before adjustment were obtained for the hazard ratios of each group.

CONCLUSION

The present study demonstrated that the SUA level was one of the most valuable predictors of cardiovascular events after PCI, with elevated SUA levels adversely affecting secondary prevention.

Management of oxidative stress and inflammation in cardiovascular diseases: mechanisms and challenges

Cardiovascular diseases (CVDs) have diverse physiopathological mechanisms with interconnected oxidative stress and inflammation as one of the common etiologies which result in the onset and development of atherosclerotic plaques. In this review, we illustrate this strong crosstalk between oxidative stress, inflammation, and CVD. Also, mitochondrial functions underlying this crosstalk, and various approaches for the prevention of redox/inflammatory biological impacts will be illustrated. In part, we focus on the laboratory biomarkers and physiological tests for the evaluation of oxidative stress status and inflammatory processes. The impact of a healthy lifestyle on CVD onset and development is displayed as well. Furthermore, the differences in oxidative stress and inflammation are related to genetic susceptibility to cardiovascular diseases and the variability in the assessment of CVDs risk between individuals; Omics technologies for measuring oxidative stress and inflammation will be explored. Finally, we display the oxidative stress-related microRNA and the functions of the redox basis of epigenetic modifications.

Detailed association between serum uric acid levels and the incidence of chronic kidney disease stratified by sex in middle-aged adults

BACKGROUND AND AIMS

Chronic kidney disease (CKD) is a global health burden. Previous studies have shown a J- or U-shaped association between serum uric acid (SUA) and cardiovascular mortality. We assessed the risk of CKD incidence in a refined SUA category in middle-aged adults stratified by sex.

METHODS

We analyzed data from 138,511 participants <65 years old (29.6% women; mean age 44.1 years) without CKD at baseline acquired from the JMDC database. The Cox model was used to assess the adjusted hazard ratio (HR).

RESULTS

During the mean follow-up period of 4.68 years, 12,589 participants developed CKD. The fully adjusted HRs (95% confidence interval [CI], p-value) for CKD incidence in men with SUA <4.0, 10.0-10.9 and ≥ 11.0 mg/dL compared to men with SUA 4.0-4.9 mg/dL were 1.13 (1.01-1.26, p = 0.030), 1.98 (1.32-2.97, p = 0.0010), and 3.74 (1.68-8.35, p = 0.0013), respectively. The fully adjusted HRs for CKD incidence in women with SUA <4.0, 8.0-8.9, and ≥9.0 mg/dL compared to women with SUA 4.0-4.9 mg/dL were 1.08 (1.01-1.16, p = 0.032), 2.39 (1.07-5.35, p = 0.034), and 3.20 (0.80-12.8, p = 0.10), respectively.

CONCLUSIONS

Both high and low SUA levels were identified as risk factors for CKD incidence in middle-aged men and women. The association of SUA levels with the increase in the risk of CKD incidence differed by sex, and the range of SUA levels associated with an increase in the risk of CKD incidence varied by sex.

Cumulative Serum Uric Acid and Its Time Course Are Associated With Risk of Myocardial Infarction and All-Cause Mortality

Background Serum uric acid (SUA) has been demonstrated as a risk factor for myocardial infarction (MI) and all-cause mortality; however, the impact of cumulative SUA (cumSUA) remains unclear. We aimed to investigate the association of cumSUA with MI risk and all-cause mortality, and to further explore the effects of SUA accumulation time course. Methods and Results The study enrolled 53 463 participants without a history of MI, and these participants underwent 3 examinations during 2006 to 2010. cumSUA from baseline to the third examination was calculated, multiplying mean values between consecutive examinations by time intervals between visits. Cox models estimated hazard ratios (HRs) and 95% CIs of MI and all-cause mortality for cumSUA quartiles, hyperuricemia exposure duration, and SUA accumulation time course. During a median follow-up of 7.04 years, 476 incident MIs and 2692 deaths occurred. In the fully adjusted model, a higher MI risk was observed in the highest cumSUA quartile (HR, 1.48; 95% CI, 1.10-1.99), in participants with longer hyperuricemia exposure duration (HR, 1.71; 95% CI, 1.06-2.73), and in participants with cumSUA≥median and a negative slope (HR, 1.58; 95% CI, 1.18-2.11). Similar associations persisted for all-cause mortality. Conclusions The risk of MI and all-cause mortality increased with higher cumSUA and was affected by the SUA accumulation time course. Early SUA accumulation contributed more to MI risk and all-cause mortality than later SUA accumulation with the same overall cumulative exposure, emphasizing the importance of optimal SUA control early in life.

Uricemia in the acute phase of myocardial infarction and its relation to long-term mortality risk

Aim: Although uric acid has antioxidant effects, hyperuricemia has been established as an indicator of increased cardiovascular mortality in various patient populations. Treatment of asymptomatic hyperuricemia in patients with acute myocardial infarction (MI) is not routinely recommended, and the efficacy of such treatment in terms of cardiovascular risk reduction remains doubtful. Materials & methods: In a prospective cohort study, we followed 5196 patients admitted for a MI between 2006 and 2018. We assessed the relationship between baseline uricemia and the incidence of all-cause death and cardiovascular mortality and the effect of long-term allopurinol treatment. Hyperuricemia was defined as serum uric acid >450 μmol/l in men and >360 μmol/l in women. Results: In the entire cohort, the 1-year all-cause and cardiovascular mortality rates were 8 and 7.4%, and the 5-year rates were 18.3 and 15.3%, respectively. Using a fully adjusted model, hyperuricemia was associated with a 70% increased risk of both all-cause death and cardiovascular mortality at 1 year, and the negative prognostic value of hyperuricemia persisted over the 5-year follow-up (for all-cause death, hazard risk ratio = 1.45 [95% CI: 1.23-1.70] and for cardiovascular mortality, hazard risk ratio = 1.52 [95% CI: 1.28-1.80], respectively). Treatment of asymptomatic hyperuricemia with allopurinol did not affect mortality rates. Conclusion: Hyperuricemia detected in patients during the acute phase of an MI appears to be independently associated with an increased risk of subsequent fatal cardiovascular events. However, hyperuricemia treatment with low-dose allopurinol did not prove beneficial for these patients.

Association Between Uric Acid, Carotid Intima-Media Thickness, and Cardiovascular Events: Prospective Results From the IMPROVE Study

Background The association between elevated serum uric acid (SUA), cardiovascular disease (CVD) risk, and carotid atherosclerosis has long been explored, and contrasting results have been reported. Therefore, the role of SUA as an independent risk factor for vascular events (VEs) and carotid atherosclerosis deserves further attention. We investigated the relationship between SUA, incident VEs, carotid intima-media thickness (cIMT), and cIMT progression in subjects at moderate-to-high CVD risk. Methods and Results In the IMPROVE (IMT-Progression as Predictors of VEs) study, 3686 participants (median age 64 years; 48% men) with ≥ 3 vascular risk factors, free from VEs at baseline, were grouped according to SUA quartiles (division points: 244-284-328 µmol/L in women, 295-336-385 µmol/L in men). Carotid-IMT and its 15-month progression, along with incident VEs, were recorded. A U-shaped association between SUA and VEs was observed in men, with 2.4-fold (P = 0.004) and 2.5-fold (P = 0.002) increased CVD risk in the first and fourth SUA quartiles as compared with the second. Adjusted hazard ratios (HRs) for cerebro-VEs in men were the highest (first and fourth quartile versus second: HR, 5.3, P = 0.010 and HR, 4.4, P = 0.023, respectively). SUA level was independently associated with cIMT progression in men (β = 0.068, P = 0.014). No significant association between SUA levels, CVD end points, and cIMT progression were found in women. Conclusions Both low and high SUA levels are associated with an increased risk of VEs in men at moderate-to-high CVD risk but not in women. Only elevated SUA levels predict cIMT progression and at a lesser but not significant extent in women.

Low Serum Uric Acid Predicts Risk of a Composite Disease Endpoint

Background and objectives: Mortality may increase in hypouricemia as well as inhyperuricemia. We assessed the predictive value of low serum uric acid (SUA) levels on the risk of overall mortality or a composite endpoint of death and nonfatal events. Materials and Methods: In 1013 community-based middle-aged adults, free of uncontrolled diabetes and coronary heart disease at baseline, the association of sex-specific SUA tertiles with defined outcomes was evaluated prospectively by logistic regression, stratified to gender and presence of type-2 diabetes, using recent criteria. Results: Totally, 43 deaths and additional incident nonfatal events in 157 cases were recorded at a median 3.4 years' follow-up. Multivariable linear regression disclosed SUA to be significantly associated among non-diabetic individuals positively with creatinine, triglycerides, and body mass index in women further with fasted glucose. In multivariable-adjusted logistic regression analysis, sex-specifically dichotomized baseline uric acid (<5.1 and <4.1 mg/dL vs. higher values) significantly predicted the non-fatal events in the whole sample (relative risk (RR) 1.51 [95% confidence interval (CI) 1.02; 2.26]), as well as in men, while composite endpoint in the whole sample tended to rise (RR 1.38). Compared with the intermediate one, the top and bottom SUA tertiles combined tended to confer mortality risk (RR 2.40 [95% CI 0.89; 6.51]). Adverse outcomes in diabetic women were predicted by tertiles 2 and 3. Conclusions: Inverse association of SUA with adverse outcomes, especially in men, is consistent with the involvement of uric acid mass in autoimmune activation. The positive association of uric acid with adverse outcomes in diabetic women is likely mediated by concomitant high-density lipoprotein dysfunction.

Serum Uric Acid and Mortality in Patients with Chronic Kidney Disease: A Systematic Review and Meta-Analysis

BACKGROUND

Existing studies suggested conflicting relationships between serum uric acid (SUA) and mortality in CKD patients. The present meta-analysis aimed to determine whether SUA can be a predictor for mortality in CKD cohorts.

METHOD

A systematical search was conducted on PubMed, EMBASE, and The Cochrane Library to identify studies reporting the relationship between SUA level and all-cause and cardiovascular mortality in CKD populations. In addition, random-effects models were adopted to calculate the hazard ratios (HRs) and corresponding 95% confidence intervals (CIs).

RESULTS

On the whole, 29 studies were involved. In the present meta-analysis, patients exhibiting the maximum SUA level showed an association with a significantly higher risk for all-cause mortality (HR, 1.30; 95% CI, 1.06-1.59) compared with patients exhibiting the minimum SUA level. As revealed from the meta-analysis of 8 studies, low level of SUA was another predictor for all-cause mortality in patients with CKD (HR, 1.36; 95% CI, 1.20-1.54). No significant relationship was identified between SUA and cardiovascular mortality.

CONCLUSIONS

Higher and lower SUA levels are both associated with significantly increased risk of all-cause mortality in patients with CKD. A appreciate dose of treatment of lowering SUA agents should be confirmed.

Why Does Hyperuricemia Not Necessarily Induce Gout?

Hyperuricemia is a risk factor for gout. It has been well observed that a large proportion of individuals with hyperuricemia have never had a gout flare(s), while some patients with gout can have a normuricemia. This raises a puzzle of the real role of serum uric acid (SUA) in the occurrence of gout flares. As the molecule of uric acid has its dual effects in vivo with antioxidant properties as well as being an inflammatory promoter, it has been placed in a delicate position in balancing metabolisms. Gout seems to be a multifactorial metabolic disease and its pathogenesis should not rely solely on hyperuricemia or monosodium urate (MSU) crystals. This critical review aims to unfold the mechanisms of the SUA role participating in gout development. It also discusses some key elements which are prerequisites for the formation of gout in association with the current therapeutic regime. The compilation should be helpful in precisely fighting for a cure of gout clinically and pharmaceutically.

Comparison of Familial, Polygenic and Biochemical Predictors of Mortality

Mortality risk is known to be associated with many physiological or biochemical risk factors, and polygenic risk scores (PRSs) may offer an additional or alternative approach to risk stratification. We have compared the predictive value of common biochemical tests, PRSs and information on parental survival in a cohort of twins and their families. Common biochemical test results were available for up to 13,365 apparently healthy men and women, aged 17-93 years (mean 49.0, standard deviation [SD] 13.7) at blood collection. PRSs for longevity were available for 14,169 study participants and reported parental survival for 25,784 participants. A search for information on date and cause of death was conducted through the Australian National Death Index, with median follow-up of 11.3 years. Cox regression was used to evaluate associations with mortality from all causes, cancers, cardiovascular diseases and other causes. Linear relationships with all-cause mortality were strongest for C-reactive protein, gamma-glutamyl transferase, glucose and alkaline phosphatase, with hazard ratios (HRs) of 1.16 (95% CI [1.07, 1.24]), 1.15 (95% CI 1.04-1.21), 1.13 (95% CI [1.08, 1.19]) and 1.11 (95% CI [1.05, 1.88]) per SD difference, respectively. Significant nonlinear effects were found for urea, uric acid and butyrylcholinesterase. Lipid risk factors were not statistically significant for mortality in our cohort. Family history and PRS showed weaker but significant associations with survival, with HR in the range 1.05 to 1.09 per SD difference. In conclusion, biochemical tests currently predict long-term mortality more strongly than genetic scores based on genotyping or on reported parental survival.

Association Between Use of Anti-gout Preparations and Dementia: Nested Case-Control Nationwide Population-Based Cohort Study

Objectives: Gout is the most common form of inflammatory arthritis and was found to be independently associated with incident dementia in the elderly. However, the associations between anti-gout preparations and dementia were not well-studied.

Methods: Data were collected from Taiwan's National Health Insurance Research Database (NHIRD). A 2005–2013 retrospective cohort study was conducted, and all investigated subjects were identified by International Statistical Classification of Diseases and Related Health Problems, 9th Revision, Clinical Modification. Conditional logistic regression was used to evaluate the odds ratio of dementia in relation to different gout preparations (benzbromarone, allopurinol, sulfinpyrazone, probenecid) and number of days of anti-gout preparation use, after adjustment for potential confounding variables.

Results: A total of 3,242 gout patients with and without dementia were selected from the NHIRD and included in the final analysis after 1:1 matching for age, gender, and diagnosis year of gout. In the anti-gout preparations, only use of Benzbromarone decreased the risk of dementia (adjusted OR, 0.81; 95% CI, 0.68–0.97). The result of the subgroup analysis revealed a trend toward a lower risk of dementia with longer use of benzbromarone. Use of benzbromarone for ≥180 days showed a significantly lower risk of dementia (adjusted OR, 0.72; 95% CI, 0.58–0.89). Moreover, the protective effect was more pronounced in males compared with females.

Conclusion: This cohort study reveals that gout patients taking benzbromarone are at a decreased risk of developing incident dementia, especially with longer use and in male. Further prospective trials are warranted to confirm our findings.

Higher uric acid is associated with better discharge recovery and short-term outcome in stroke patients treated with thrombolysis

BACKGROUND

Uric acid (UA) possesses antioxidant features and potential neuroprotective effects. However, conflicting results regarding the association between serum uric acid (SUA) levels and the prognosis of stroke have been obtained. We aimed to assess whether SUA is related to discharge recovery and short-term outcomes in patients who underwent thrombolysis therapy.

METHODS

We recruited 393 consecutive patients who were diagnosed with acute ischaemic stroke (AIS) and treated with thrombolysis. The demographic information, including sex and age, was collected. Haematology tests, including SUA, fasting plasma glucose (FPG), and blood lipid parameters, were performed under fasting conditions the morning after admission. The modified Rankin Scale (mRS) was used to assess the functional outcome of patients at discharge and 3 months after onset.

RESULTS

A negative correlation was observed between the levels of SUA and the National Institute of Health Stroke Scale (NIHSS) score at discharge (r = - 0.171, P = 0.003). Additionally, a positive correlation was observed between the levels of SUA and the difference between the baseline NIHSS and discharge NIHSS (r = 0.118, P = 0.032). The levels of SUA in the patients with good outcomes (353.76 ± 93.05) were higher than those in the patients with poor outcomes (301.99 ± 92.24; P = 0.015) at 3 months. The multivariate logistic regression analysis demonstrated that a higher SUA level (odds ratio 0.988, 95% confidence interval 0.985-0.991, P = 0.002) was an independent predictor of a good outcome at 3 months.

CONCLUSION

Higher SUA levels were associated with better discharge recovery and 3-month outcomes in patients with ischaemic stroke who received thrombolysis.

[Asymptomatic Hyperuricemia and Risk Of Cardiovascular and Renal Diseases]

Asymptomatic hyperuricemia (HU) is common in the population and significantly contributes to the general cardiovascular risk. Despite extensive study of this condition there is still no conclusive answers to questions about detection of asymptomatic HU and its effect on the risk for development and progression of cardiovascular and kidney diseases. This review summarizes key information about these issues, which has been accumulated by the present time.

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).

Friend or Foe? An Unrecognized Role of Uric Acid in Cancer Development and the Potential Anticancer Effects of Uric Acid-lowering Drugs

In recent years, metabolic syndrome (Mets) has been a hot topic among medical scientists. Mets has an intimate relationship with the incidence and development of various cancers. As a contributory factor of Mets, hyperuricemia actually plays an inseparable role in the formation of various metabolic disorders. Although uric acid is classically considered an antioxidant with beneficial effects, mounting evidence indicates that a high serum uric acid (SUA) level may serve as a pro-oxidant to generate inflammatory reactions and oxidative stress. In this review, we describe the unrecognized role of hyperuricemia in cancer development and summarize major mechanisms linking uric acid to carcinogenesis. Furthermore, we also discuss the potential mechanism of liver metastasis of cancer and list some types of uric acid-lowering agents, which may exert anticancer effects.

The Complex Relationship Between Serum Uric Acid, Endothelial Function and Small Vessel Remodeling in Humans

Aims: The relationship between serum uric acid (SUA) and microvascular remodeling in humans remains largely unexplored. We assessed whether SUA provides additional information on the severity of microvascular remodeling than that obtained from the European Heart Score (HS), the patterns of microvascular remodeling associated with changes in SUA levels and the mediation by endothelial function and nitric oxide (NO) availability on this relationship. Methods: A total of 162 patients included in the microvascular dataset of the Italian Society of Hypertension with available information on SUA, media-to-lumen (M/L) ratio, media cross-sectional area (MCSA), endothelial function, NO availability and HS were included in the analysis. The top tertile of M/L ratio and MCSA were used to define severe microvascular remodeling. Results: A U-shaped association was observed between SUA and both M/L ratio and MCSA. Adjustment for HS did not affect these associations. SUA was able to reclassify a significant number of subjects without, and with, severe M/L ratio and MCSA remodeling over the HS alone. The microvascular remodeling associated with SUA levels presented a predominant hypertrophic pattern. SUA was inversely associated with endothelial function and NO availability. Structural equation modeling analysis controlling for the HS suggested that the association of SUA with M/L ratio and MCSA was mediated through changes in endothelial function and NO availability. Conclusions: The addition of SUA to the HS improves the identification of subjects with greater microvascular remodeling. The relationship between SUA and microvascular remodeling is mediated by endothelial function and NO availability.