Association of plasma uric acid with ischaemic heart disease and blood pressure: mendelian randomisation analysis of two large cohorts

Kidney function, uric acid, and risk of atrial fibrillation: experience from the AMORIS cohort

BACKGROUND

Uric acid closely relates to both kidney disease and atrial fibrillation (AF), yet the extent to which it influences the kidney-AF association remains uncertain. We examined the relationship between kidney function and risk of AF, accounting for uric acid levels.

METHODS

A total of 308,509 individuals in the Swedish Apolipoprotein-Related Mortality Risk (AMORIS) cohort were included and their serum creatinine and uric acid were measured during 1985-1996. Ten-year incident AF was identified via linkage with the national registers. Glomerular filtration rate (eGFR) (ml/min/1.73 m2) was calculated with the 2009 Chronic Kidney Disease Epidemiology Collaboration equation. Hyperuricemia was defined as > 420 µmol/L for men and > 360 µmol/L for women.

RESULTS

Over a mean follow-up of 9.4 years, 10,007 (3.2%) incident AF cases occurred. After adjusting for age, sex, cardiovascular diseases, total cholesterol, triglycerides, and glucose, individuals with low eGFR (< 30 and 30-59 ml/min/1.73 m2 ) had a higher risk of AF compared to those with normal eGFR (60-89) (hazard ratio (HR) = 1.72, 95% confidence interval (CI):1.29-2.30; HR = 1.10, 95% CI: 1.03-1.18, respectively). After further adjusting for uric acid levels, the association disappeared (HR = 0.97, 95% CI: 0.72-1.30; HR = 0.93, 95% CI: 0.86-1.00, respectively). When stratifying by hyperuricemia yes/no, eGFR < 30 ml/min/1.73 m2 was associated with higher AF risk in a small group of individuals without hyperuricemia (HR = 2.58, 95% CI: 1.64-4.07).

CONCLUSION

Uric acid largely accounted for the relationship between eGFR and AF in this study. However, in individuals without hyperuricemia, eGFR in the lowest range (< 30 ml/min/1.73 m2) was still associated with increased risk of AF.

Effect of cumulative uric acid to high-density lipoprotein cholesterol ratio on myocardial infarction in prospective cohorts

OBJECTIVE

This study aimed to investigate the effect of the ratio of cumUHR on MI, based on the hypothesis that higher exposure to the ratio of cumUHR is associated with a higher risk of MI.

METHODS

Participants who underwent three examinations between 2006 and 2010 were selected. The cumUHR from baseline to the third check was calculated, multiplying the mean between consecutive checks by the time interval between visits. The association between cumUHR and MI and its progression was evaluated by Cox proportional hazards regression model. The cumulative incidence of endpoint events between cumUHR groups was compared using a log-rank test. Stratification by age, sex, and BMI was further performed.

RESULTS

A total of 53,697 people, with an average age of 53.08 years, 78 % of whom were male, with a median follow-up of 10.51 years and 744 myocardial infarction events, were enrolled. The highest cumUHR quartile, MI, had the highest cumulative incidence (log-rank P < 0.01). Multivariate COX regression analysis showed that in the fully adjusted model, there was a high level of concentration in the highest cumUHR quartile (HR, 1.52; 95 % CI, 1.20-1.92) and participants with longer duration of high UHR exposure (HR, 1.55; 95 % CI, 1.22-1.97).

CONCLUSIONS

The risk of MI increases with cumUHR and is influenced by the time course of cumUHR. In particular, in people aged ≥ 60 years, males, and BMI < 28 kg/m2, the risk of MI is more affected by the level of UHR, and more attention should be paid to controlling the level of UHR.

Empagliflozin lowers serum uric acid in chronic kidney disease: exploratory analyses from the EMPA-KIDNEY trial

BACKGROUND AND HYPOTHESIS

Hyperuricaemia and gout are common in chronic kidney disease (CKD). We aimed to assess the effects of sodium-glucose co-transporter-2 (SGLT2) inhibition on uric acid (urate) and gout in patients with CKD.

METHODS

The EMPA-KIDNEY trial randomised 6609 patients with CKD (estimated glomerular filtration rate [eGFR] ≥20 and <90 mL/min/1.73m2) to receive either empagliflozin 10 mg daily or matching placebo over a median of two years follow-up. Serum uric acid was measured at randomisation then 2 and 18 months of follow-up and the effects of empagliflozin were analysed using a pre-specified mixed model repeated measures approach. Participant-reported gout events were analysed in Cox regression models (first events) with the Andersen-Gill extension (total events). A post-hoc composite outcome included new initiation of uric acid lowering therapy or colchicine. EMPA-KIDNEY primary and kidney disease progression outcomes were also assessed in subgroups of baseline serum uric acid.

RESULTS

Baseline mean ± SD serum uric acid concentration was 431±114 µmol/L. Allocation to empagliflozin resulted in a study-average between-group difference in serum uric acid of -25.6 (95%CI -30.3,-21.0) µmol/L with larger effects in those with higher eGFR (trend P < 0.001) and without diabetes (heterogeneity P < 0.001). Compared to placebo, empagliflozin did not significantly reduce first or total gout events (HR 0.87, 95%CI 0.74-1.02 for the 595 first events, and 0.86, 0.72-1.03 for the 869 total events) with similar hazard ratios for the post-hoc composite and across subgroups, including by diabetes and eGFR. The effect of empagliflozin on the primary outcome and kidney disease progression outcomes were similar irrespective of baseline level of uric acid.

CONCLUSION

SGLT2 inhibition reduces serum uric acid in patients with CKD with larger effects at higher eGFR and in the absence of diabetes. However, the effect on uric acid is modest and did not translate into reduced risk of gout in EMPA-KIDNEY.

Hyperuricemia and its related diseases: mechanisms and advances in therapy

Hyperuricemia, characterized by elevated levels of serum uric acid (SUA), is linked to a spectrum of commodities such as gout, cardiovascular diseases, renal disorders, metabolic syndrome, and diabetes, etc. Significantly impairing the quality of life for those affected, the prevalence of hyperuricemia is an upward trend globally, especially in most developed countries. UA possesses a multifaceted role, such as antioxidant, pro-oxidative, pro-inflammatory, nitric oxide modulating, anti-aging, and immune effects, which are significant in both physiological and pathological contexts. The equilibrium of circulating urate levels hinges on the interplay between production and excretion, a delicate balance orchestrated by urate transporter functions across various epithelial tissues and cell types. While existing research has identified hyperuricemia involvement in numerous biological processes and signaling pathways, the precise mechanisms connecting elevated UA levels to disease etiology remain to be fully elucidated. In addition, the influence of genetic susceptibilities and environmental determinants on hyperuricemia calls for a detailed and nuanced examination. This review compiles data from global epidemiological studies and clinical practices, exploring the physiological processes and the genetic foundations of urate transporters in depth. Furthermore, we uncover the complex mechanisms by which the UA induced inflammation influences metabolic processes in individuals with hyperuricemia and the association with its relative disease, offering a foundation for innovative therapeutic approaches and advanced pharmacological strategies.

[Association between serum uric acid and airflow obstruction based on the health-checkup population]

OBJECTIVE

To investigate the association between serum uric acid, pulmonary function and airflow obstruction in Chinese Taiwan healthy subjects.

METHODS

All the cross-sectional analysis was performed in the population over 40 years old using the physical examination data of Chinese Taiwan MJ Health Resource Center between 1996 and 2016 stratification by gender. The correlation analyses between serum uric acid were done and multivariate Logistic regression analysis was used to explore the effect of serum uric acid on airflow obstruction.

RESULTS

A total of 35 465 people were included in the study, including 16 411 men and 19 054 women. Among them, the serum uric acid concentration of men was higher than that of women, and the serum uric acid concentration of the people with airflow obstruction was higher than that of the people without airflow obstruction. There was a negative correlation between serum uric acid level and the forced expiratory volume in one second (FEV1) and the force vital capacity (FVC) in women (P < 0.05), but in men the correlation didn' t exist (P>0.05). After adjusting for age, education, smoking status, drinking status, work strength, body mass index, history of cough, history of hypertension, history of diabetes, history of dyslipidemia, white blood cells and blood albumin, the airflow obstruction in women was more likely to exist with the serum uric acid elevated (OR=1. 12, 95%CI: 1.02-1.22, P < 0.05). The results showed that women with hyperuricemia were more likely to have airflow obstruction than those without hyperuricemia (OR=1.36, 95%CI: 1.06-1.75, P < 0.05). There was no correlation between serum uric acid concentration and airflow obstruction in men (OR=1.04, 95%CI: 0.96-1.13, P>0.05), also the hyperuricemia and airflow obstruction (OR=1.12, 95%CI: 0.89-1.39, P>0.05).

CONCLUSION

There is a negative correlation between serum uric acid and FEV1 and FVC in relatively healthy women, and there is an association between elevated serum uric acid and airflow obstruction in women, but not in men. Further prospective studies are needed to explore whether high serum uric acid level can increase the risk of airflow obstruction.

Use of Mendelian randomization to assess the causal status of modifiable exposures for rheumatic diseases

The explosion in Mendelian randomization (MR) publications is hard to ignore and shows no signs of slowing. Clinician readers, who may not be familiar with jargon-ridden methods, are expected to discern the good from the many low-quality studies that make overconfident claims of causality or stretch the plausibility of what MR can investigate. We aim to equip readers with foundational concepts, contextualized using examples in rheumatology, to appraise the many MR papers that are or will appear in their journals. We highlight the importance of assessing whether exposures are under plausibly specific genetic influence, whether the hypothesized causal pathways make biological sense, and whether results stand up to replication and use of control outcomes. Quality of research can vary substantially using MR as with any design, and all methods have inherent limitations. MR studies have provided and can still contribute valuable insights in the context of evidence triangulation.

Does Serum Uric Acid to Creatinine Ratio Predict Mortality Risk in Patients With Heart Failure?

BACKGROUND

Previous studies have established a positive correlation between serum uric acid to creatinine (SUA/Cr) ratio and cardiovascular disease, but the relationship between SUA/Cr ratio and the prognosis of heart failure (HF) remains unknown. This study investigated the potential of SUA/Cr ratio as a prognostic predictor for patients with HF.

METHODS

This single-center prospective cohort study enrolled 2,122 patients with HF between March 2013 and June 2017. All patients were divided into 3 groups according to SUA/Cr ratio tertiles and were followed up with until December 31, 2022. The association between SUA/Cr ratio and the prognosis of HF was assessed using the Cox proportional hazards model.

RESULTS

The mean (SD) age and mean (SD) SUA/Cr ratio of the study cohort (66% male) were 59.3 (14.7) years and 4.71 (2.09), respectively. During a median follow-up period of 15 months (range, 11-26 months), 390 end-point events were observed. Prognosis analysis revealed that a high SUA/Cr ratio was associated with an increased mortality risk of HF (hazard ratio, 1.62 [95% CI, 1.26-2.09]; P < .001) compared with the SUA/Cr ratio in the lowest tertile. After adjusting for covariates, the hazard ratio for mortality risk of HF was 1.71 (95% CI, 1.23-2.37; P = .001). Subgroup analysis showed that mortality risk increased in direct proportion with the SUA/Cr ratio in female patients, patients with a history of hypertension and β-blocker use, and patients with UA levels below 428 μmol/L and creatinine levels less than 97 mg/dL. Stratification by age; by history of diabetes, hyperlipidemia, and smoking; and by level of fasting plasma glucose, however, had no obvious effect on the association between SUA/Cr ratio and HF prognosis. Patients with higher SUA/Cr ratios had reduced left ventricular ejection fraction and increased left ventricular end-diastolic diameter.

CONCLUSION

A high SUA/Cr ratio was an independent risk factor for the mortality risk of HF.

Large-scale cross-ancestry genome-wide meta-analysis of serum urate

Hyperuricemia is an essential causal risk factor for gout and is associated with cardiometabolic diseases. Given the limited contribution of East Asian ancestry to genome-wide association studies of serum urate, the genetic architecture of serum urate requires exploration. A large-scale cross-ancestry genome-wide association meta-analysis of 1,029,323 individuals and ancestry-specific meta-analysis identifies a total of 351 loci, including 17 previously unreported loci. The genetic architecture of serum urate control is similar between European and East Asian populations. A transcriptome-wide association study, enrichment analysis, and colocalization analysis in relevant tissues identify candidate serum urate-associated genes, including CTBP1, SKIV2L, and WWP2. A phenome-wide association study using polygenic risk scores identifies serum urate-correlated diseases including heart failure and hypertension. Mendelian randomization and mediation analyses show that serum urate-associated genes might have a causal relationship with serum urate-correlated diseases via mediation effects. This study elucidates our understanding of the genetic architecture of serum urate control.

Mendelian randomization analysis of 34,497 German Holstein cows to infer causal associations between milk production and health traits

BACKGROUND

Claw diseases and mastitis represent the most important health issues in dairy cattle with a frequently mentioned connection to milk production. Although many studies have aimed at investigating this connection in more detail by estimating genetic correlations, they do not provide information about causality. An alternative is to carry out Mendelian randomization (MR) studies using genetic variants to investigate the effect of an exposure on an outcome trait mediated by genetic variants. No study has yet investigated the causal association of milk yield (MY) with health traits in dairy cattle. Hence, we performed a MR analysis of MY and seven health traits using imputed whole-genome sequence data from 34,497 German Holstein cows. We applied a method that uses summary statistics and removes horizontal pleiotropic variants (having an effect on both traits), which improves the power and unbiasedness of MR studies. In addition, genetic correlations between MY and each health trait were estimated to compare them with the estimates of causal effects that we expected.

RESULTS

All genetic correlations between MY and each health trait were negative, ranging from - 0.303 (mastitis) to - 0.019 (digital dermatitis), which indicates a reduced health status as MY increases. The only non-significant correlation was between MY and digital dermatitis. In addition, each causal association was negative, ranging from - 0.131 (mastitis) to - 0.034 (laminitis), but the number of significant associations was reduced to five nominal and two experiment-wide significant results. The latter were between MY and mastitis and between MY and digital phlegmon. Horizontal pleiotropic variants were identified for mastitis, digital dermatitis and digital phlegmon. They were located within or nearby variants that were previously reported to have a horizontal pleiotropic effect, e.g., on milk production and somatic cell count.

CONCLUSIONS

Our results confirm the known negative genetic connection between health traits and MY in dairy cattle. In addition, they provide new information about causality, which for example points to the negative energy balance mediating the connection between these traits. This knowledge helps to better understand whether the negative genetic correlation is based on pleiotropy, linkage between causal variants for both trait complexes, or indeed on a causal association.

Efficacy and safety of orlistat in male patients with overweight/obesity and hyperuricemia: results of a randomized, double-blind, placebo-controlled trial

BACKGROUND

Obesity is associated with elevated serum uric acid (SUA) levels and frequent gout flares. Losing weight can reduce the SUA level and gout flares. The effect of orlistat on SUA levels and gout flares in patients with overweight/obesity and hyperuricemia (HUA) has not been extensively studied. This study investigated the effects of orlistat on SUA levels and gout flares compared to placebo in overweight and obese patients with HUA.

METHODS

A total of 72 Chinese patients with overweight/obesity and HUA were randomly divided into a placebo group (35, 48.6%) and an orlistat group (37, 51.4%); the trial lasted 12 weeks. The primary endpoints were the relative changes in body weight, the SUA level, and gout flares in the per-protocol population.

RESULTS

Orlistat reduced the proportion of patients with gout flares (log-rank P = 0.023, hazard ratio = 0.31, 95% confidence interval 0.11-0.85). There was no significant difference in SUA level between the two groups. The average weight loss of the orlistat group was 2.85 kg, and the average weight loss of the placebo group was 0.76 kg. The weight loss in the orlistat group was significantly greater than that in the control group (P < 0.05).

CONCLUSIONS

This study is the first to demonstrate that orlistat has no significant effect on SUA levels in patients with overweight/obesity and HUA. The utility of orlistat as an adjunct therapy to prevent gout flares during weight loss in patients with HUA was emphasized.

TRIAL REGISTRATION

Clinicaltrials.gov NCT05496075.

Sjögren's Disease and Oral Health: A Genetic Instrumental Variable Analysis

Epidemiological studies have consistently shown that Sjögren's disease (SjD) increases the risk of dental caries. Despite similar evidence indicating an elevated risk of periodontitis, SjD remains a disputed risk factor for this disease. The risk of bias in observational research is a major impediment to confirming this link. Within an instrumental variable framework, genetic variants associated with a risk factor can be used to proxy its effect on an outcome while avoiding common sources of observational study bias. In this study, we leveraged an instrumental variable approach to investigate whether SjD affects the risk of caries and periodontitis. A total of 57 genetic variants strongly associated with SjD were identified from a genome-wide association study of 2,247 European descent cases and 332,115 controls. We tested for associations of these genetic instruments with caries (measured as the number of decayed, missing, and filled surfaces in 26,792 individuals) and periodontitis (17,353 clinical periodontitis cases and 28,210 European controls). Several sensitivity analyses were used to further validate the primary inverse variance weighted (IVW) estimate. IVW analysis revealed an adverse effect of SjD on caries (β = 0.039, P = 6.3e-16) and periodontitis (odds ratio = 1.033, P = 2.3e-05). Sensitivity analyses, conducted to assess the robustness to potential violations of instrumental variable assumptions, further support these findings. Our results showed that SjD has a detrimental effect on caries and also suggest that SjD promotes periodontitis.

Effects of uric acid on ischemic diseases, stratified by lipid levels: a drug-target, nonlinear Mendelian randomization study

Although uric acid-lowering agents such as xanthine oxidase inhibitors have potential cardioprotective effects, studies on their use in preventing cardiovascular diseases are lacking. We investigated the genetically proxied effects of reducing uric acid on ischemic cardiovascular diseases in a lipid-level-stratified population. We performed drug-target Mendelian randomization (MR) analyses using UK Biobank data to select genetic instruments within a uric acid-lowering gene, xanthine dehydrogenase (XDH), and construct genetic scores. For nonlinear MR analyses, individuals were stratified by lipid level. Outcomes included acute myocardial infarction (AMI), ischemic heart disease, cerebral infarction, transient cerebral ischemic attack, overall ischemic disease, and gout. We included 474,983 non-gout individuals with XDH-associated single-nucleotide polymorphisms. The XDH-variant-induced uric acid reduction was associated with reduced risk of gout (odds ratio [OR], 0.85; 95% confidence interval [CI], 0.78-0.93; P < 0.001), cerebral infarction (OR, 0.86; 95% CI, 0.75-0.98; P = 0.023), AMI (OR, 0.79; 95% CI, 0.66-0.94; P = 0.010) in individuals with triglycerides ≥ 188.00 mg/dL, and cerebral infarction in individuals with low-density lipoprotein cholesterol (LDL-C) ≤ 112.30 mg/dL (OR, 0.76; 95% CI, 0.61-0.96; P = 0.020) or LDL-C of 136.90-157.40 mg/dL (OR, 0.67; 95% CI, 0.49-0.92; P = 0.012). XDH-variant-induced uric acid reduction lowers the risk of gout, AMI for individuals with high triglycerides, and cerebral infarction except for individuals with high LDL-C, highlighting the potential heterogeneity in the protective effects of xanthine oxidase inhibitors for treating AMI and cerebral infarction depending on the lipid profiles.

Exploring the Multifaceted Nexus of Uric Acid and Health: A Review of Recent Studies on Diverse Diseases

The prevalence of patients with hyperuricemia or gout is increasing worldwide. Hyperuricemia and gout are primarily attributed to genetic factors, along with lifestyle factors like consuming a purine-rich diet, alcohol and/or fructose intake, and physical activity. While numerous studies have reported various comorbidities linked to hyperuricemia or gout, the range of these associations is extensive. This review article focuses on the relationship between uric acid and thirteen specific domains: transporters, genetic factors, diet, lifestyle, gout, diabetes mellitus, metabolic syndrome, atherosclerosis, hypertension, kidney diseases, cardiovascular diseases, neurological diseases, and malignancies. The present article provides a comprehensive review of recent developments in these areas, compiled by experts from the Young Committee of the Japanese Society of Gout and Uric and Nucleic Acids. The consolidated summary serves to enhance the global comprehension of uric acid-related matters.

High-normal serum uric acid predicts macrovascular events in patients with type 2 diabetes mellitus without hyperuricemia based on a 10-year cohort

BACKGROUND AND AIMS

The upper limits of normal serum uric acid (SUA) or the lower limits of hyperuricemia were frequently set at 420 or 360 μmol/L (7.0 or 6.0 mg/dL). We aimed to explore the association between high-normal SUA (360 ≤ SUA≤420 μmol/L) and incidence of macrovascular and renal events based on a 10-year cohort with type 2 diabetes mellitus (T2DM) to explore which cut-off was more appropriate.

METHODS AND RESULTS

A total of 2988 patients with T2DM without hyperuricemia (SUA≤420 μmol/L) were included and followed up. Cox proportional hazards models and restricted cubic spline regression were used to evaluate the relationship between baseline SUA (as continuous and categorical variable) and macrovascular and renal events. Patients were grouped as low-normal (SUA<360 μmol/L) and high-normal groups based on baseline SUA, and the latter group had higher incidence of macrovascular events. Multivariate Cox regression analysis indicated that baseline levels of SUA were significantly associated with cardiovascular (HR = 1.385, 95%CI:1.190-1.613, P < 0.001) and peripheral vascular events (HR = 1.266, 95%CI:1.018-1.574, P = 0.034), and the linear association existed. Moreover, fully adjusted multivariable Cox analyses indicated high-normal SUA increased the risks of cardiovascular (HR = 1.835, 95%CI:1.319-2.554, P < 0.001) and peripheral vascular events (HR = 1.661, 95%CI:1.000-2.760, P = 0.050) compared to low-normal SUA.

CONCLUSIONS

Baseline SUA levels were positively associated with cardiovascular and peripheral vascular events, and high-normal SUA increased the risks of these events in patients with T2DM even without hyperuricemia. A threshold value for SUA of 360 μmol/L should be more appropriate in terms of predicting macrovascular events risks compared to the value of 420 μmol/L.

Associations between obesity parameters and hyperuricemia by sex, age, and diabetes mellitus: A nationwide study in Korea

OBJECTIVE

We investigated the associations between obesity parameters and the risk of hyperuricemia among Korean adults by sex, age, and diabetes mellitus status.

METHODS

This study analyzed data from 17,753 adults from the Korea National Health and Nutrition Examination Survey (KNHANES) 2016-2018. Multivariable logistic regression analyses were conducted to examine the associations of body mass index (BMI), waist circumference (WC), and general and abdominal obesity with the risk of hyperuricemia (serum uric acid ≥7.0 mg/dL in men and ≥6.0 mg/dL in women).

RESULTS

Of all the participants, 12.7% (n = 2256) had hyperuricemia. The age-adjusted mean serum uric acid levels increased significantly with increasing BMI and WC (P for trend <0.001). The adjusted odds ratios (ORs) of hyperuricemia increased as BMI and WC increased in both sexes (P for trend <0.001). General (OR 1.98, 95% confidence interval [CI]: 1.69-2.32) and abdominal (OR 2.21, 95% CI: 1.89-2.58) obesity in men and general (OR 3.26, 95% CI: 2.60-4.09) and abdominal (OR 3.43, 95% CI: 2.69-4.37) obesity in women were associated with higher risks of hyperuricemia. These associations were prominent in women. The association between abdominal obesity and hyperuricemia persisted after additional adjustments for BMI in both sexes. Significant interactions were observed in younger adults and individuals without diabetes mellitus.

CONCLUSION

Increased BMI and WC, and general and abdominal obesity, may be important risk factors for hyperuricemia in both sexes. Women, young adults, and individuals without diabetes mellitus require particular attention to prevent obesity and hyperuricemia.

Guidelines for performing Mendelian randomization investigations: update for summer 2023

This paper provides guidelines for performing Mendelian randomization investigations. It is aimed at practitioners seeking to undertake analyses and write up their findings, and at journal editors and reviewers seeking to assess Mendelian randomization manuscripts. The guidelines are divided into ten sections: motivation and scope, data sources, choice of genetic variants, variant harmonization, primary analysis, supplementary and sensitivity analyses (one section on robust statistical methods and one on other approaches), extensions and additional analyses, data presentation, and interpretation. These guidelines will be updated based on feedback from the community and advances in the field. Updates will be made periodically as needed, and at least every 24 months.

Sugar, salt, immunity and the cause of primary hypertension

Despite its discovery more than 150 years ago, the cause of primary hypertension remains unknown. Most studies suggest that hypertension involves genetic, congenital or acquired risk factors that result in a relative inability of the kidney to excrete salt (sodium chloride) in the kidneys. Here we review recent studies that suggest there may be two phases, with an initial phase driven by renal vasoconstriction that causes low-grade ischemia to the kidney, followed by the infiltration of immune cells that leads to a local autoimmune reaction that maintains the renal vasoconstriction. Evidence suggests that multiple mechanisms could trigger the initial renal vasoconstriction, but one way may involve fructose that is provided in the diet (such as from table sugar or high fructose corn syrup) or produced endogenously. The fructose metabolism increases intracellular uric acid, which recruits NADPH oxidase to the mitochondria while inhibiting AMP-activated protein kinase. A drop in intracellular ATP level occurs, triggering a survival response. Leptin levels rise, triggering activation of the sympathetic central nervous system, while vasopressin levels rise, causing vasoconstriction in its own right and stimulating aldosterone production via the vasopressin 1b receptor. Low-grade renal injury and autoimmune-mediated inflammation occur. High-salt diets can amplify this process by raising osmolality and triggering more fructose production. Thus, primary hypertension may result from the overactivation of a survival response triggered by fructose metabolism. Restricting salt and sugar and hydrating with ample water may be helpful in the prevention of primary hypertension.

Update in uric acid, hypertension, and cardiovascular diseases

A direct relationship between serum uric acid levels and hypertension, cardiovascular, renal and metabolic diseases has been reported in many basic and epidemiological studies. Among these, high blood pression is one of the most common features associated with hyperuricemia. In this regard, several small-scale interventional studies have demonstrated a significant reduction in blood pressure in hypertensive or prehypertensive patients on uric acid-lowering drugs. These observation or intervention studies have led to affirm that there is a causal relationship between uric acid and hypertension. While the clinical association between uric acid and high blood pressure is notable, no clear conclusion has yet been reached as to whether lowering uric acid is beneficial to prevent cardiovascular and renal metabolic diseases. Recently, several prospective randomized controlled intervention trials using allopurinol and other uric acid-lowering drugs have been reported, and the results from these trials were almost negative, suggesting that the correlation between hyperuricemia and cardiovascular disease has no causality. However, it is important to note that in some of these recent studies there were high dropout rates and an important fraction of participants were not hyperuricemic. Therefore, we should carry caution in interpreting the results of these studies. This review article presents the results of recent clinical trials using uric acid-lowering drugs, focusing on hypertension and cardiovascular and renal metabolic diseases, and discusses the future of uric acid therapy.

Association of Normal Serum Uric Acid Level and Cardiovascular Disease in People Without Risk Factors for Cardiac Diseases in China

Background Healthy individuals with normal level of serum uric acid (SUA) may not be truly at the lowest risk of cardiovascular disease (CVD). This study aimed to assess the association of SUA levels with CVD and its subtypes in people without CVD risk factors and determine a suitable target of SUA to prevent CVD. Methods and Results We enrolled 25 284 participants who were free of CVD, absent of CVD risk factors, and with an SUA level between 180 and 359 μmol/L (3-6 mg/dL) at baseline from the Kailuan study. Cox proportional hazards models were applied to calculated adjusted hazard ratio (HR) and 95% CI for the risk of CVD and its subtypes. During a median follow-up of 12.97 years (interquartile range, 12.68-13.16 years), we identified 1007 cases of CVD. There was an increase in the risk of incident CVD with increasing SUA levels (P_trend=0.0011). Compared with participants with SUA levels of 180 to 239 μmol/L (3-4 mg/dL), the HR of CVD was 1.12 (95% CI, 0.96-1.31) and 1.28 (95% CI, 1.08-1.52) for SUA levels of 240 to 299 μmol/L (4-5 mg/dL) and 300 to 359 μmol/L (5-6 mg/dL), respectively. A multivariable-adjusted spline regression model showed a J-shaped association between SUA and the risk of CVD. Similar results were observed for stroke and myocardial infarction. Conclusions The risk of incident CVD increased with elevating SUA levels among individuals without hyperuricemia or other traditional CVD risk factors. These findings highlighted the importance of primordial prevention for SUA level increase along with other traditional CVD risk factors.

U-shaped association of serum uric acid with cardiovascular disease risk scores and the modifying role of sex among Chinese adults

BACKGROUND AND AIMS

Serum uric acid (SUA) is involved in the development of cardiovascular disease (CVD). However, information on the dose-response relationship between SUA and CVD is limited in the Chinese population. This study aimed to investigate the potential nonlinear dose-response association of SUA with CVD risk in a Chinese population and to explore the effect of sex on these associations.

METHODS AND RESULTS

Cross-sectional data, from 6252 Chinese adults aged 30-74 years who participated in the China Health and Nutrition Survey 2009, were stratified by SUA deciles. The 10-year risk of CVD was determined using the Framingham risk score. A restricted cubic spline (RCS) was incorporated into the logistic models to assess the nonlinear relationship between SUA and CVD. Among the participants, 65%, 20%, and 15% had low, moderate, and high 10-year CVD risks, respectively. Compared with the reference SUA strata of 225 to <249 μmol/L, CVD risk was significantly increased at SUA ≥294 μmol/L, with adjusted ORs ranging from 2.39 (1.33-4.33) to 4.25 (2.37-7.65). An increasingly higher nonsignificant CVD risk was found at SUA <225 μmol/L and showed a nonlinear U-shaped association. In the fitted RCS model, an approximate U-shaped association between SUA and CVD risk scores was found in women, but this significant nonlinear relationship was not found in men.

CONCLUSION

This study showed that both lower and higher SUA levels were associated with a higher 10-year CVD risk among Chinese adults, forming a U-shaped relationship, and this pattern was particularly pronounced for women.

Trends in serum uric acid levels among Korean children and adolescents between 2016 and 2020: a nationwide study

The aim of this study was to examine trends in serum uric acid (SUA) levels over a recent 5-year period according to age, sex, obesity, and abdominal obesity among Korean children and adolescents. We conducted a serial cross-sectional analysis using nationally representative data from the Korea National Health and Nutritional Examination Survey from 2016 to 2020. The study outcome was trends in SUA levels. SUA trends were analyzed by survey-weighted linear regression analysis considering the survey year as a continuous variable. SUA trends were also analyzed for subgroups based on age, sex, abdominal obesity, or obesity. This study included 3,554 children and adolescents aged 10-18 years. SUA increased significantly over the study period in boys (p for trend = 0.043), but not in girls (p for trend = 0.300). In age-specific analyses, SUA increased significantly in the 10-12 years group (p for trend = 0.029). After adjusting for age, SUA increased significantly in the obese group of both boys (p for trend = 0.026) and girls (p for trend = 0.023), but not in the overweight, normal, or under-weight groups of either sex. After adjusting for age, SUA increased significantly in the abdominal obesity group of boys (p for trend = 0.017) and girls (p for trend = 0.014), but not in the non-abdominal obesity group of either sex.   Conclusion: In the current study, SUA levels significantly increased in both boys and girls with obesity or abdominal obesity. Further studies of the effect of SUA on health outcomes in boys and girls with obesity or abdominal obesity are needed. What is Known: • High serum uric acid (SUA) is a risk factor for various metabolic diseases, including gout, hypertension, and type 2 diabetes. What is New: • SUA levels increased in boys and the 10-12 years group of Korean children and adolescents. • SUA levels increased significantly in Korean children and adolescents with obesity or central obesity.

Metabolic Syndrome and Its Components Are Associated with New-Onset Hyperuricemia in a Large Taiwanese Population Follow-Up Study

The prevalence rate of hyperuricemia remains high in Taiwan, at 21.6% in men and 9.57% in women. Both metabolic syndrome (MetS) and hyperuricemia can cause many complications; however, few studies have evaluated the correlation between MetS and hyperuricemia. Therefore, in this observational cohort study, we explored associations between metabolic syndrome (MetS) and its components and new-onset hyperuricemia. Of 27,033 individuals in the Taiwan Biobank who had complete follow-up data, we excluded those with hyperuricemia at baseline (n = 4871), those with gout at baseline (n = 1043), those with no data on baseline uric acid (n = 18), and those with no data on follow-up uric acid (n = 71). The remaining 21,030 participants (mean age 50.8 ± 10.3 years) were enrolled. We found a significant association between new-onset hyperuricemia with MetS and the components of MetS (hypertriglyceridemia, abdominal obesity, low high-density lipoprotein cholesterol, hyperglycemia, and high blood pressure). Furthermore, compared to those without any MetS components, those with one MetS component (OR = 1.816), two MetS components (OR = 2.727), three MetS components (OR = 3.208), four MetS components (OR = 4.256), and five MetS components (OR = 5.282) were significantly associated with new-onset hyperuricemia (all p < 0.001). MetS and its five components were associated with new-onset hyperuricemia in the enrolled participants. Further, an increase in the number of MetS components was associated with an increase in the incidence rate of new-onset hyperuricemia.

Outcome Monitoring After Cardiac Surgery (OMACS): a single-centre prospective cohort study of cardiac surgery patients

INTRODUCTION

More than 30 000 cardiac surgery procedures are performed in the UK each year, however, postoperative complications and long-term failure of interventions are common, leading to repeated surgeries. This represents a significant burden on the patient and health service.Routinely, patients are discharged to their general practitioner 6 weeks postoperatively and research studies typically only report short-term outcomes up to 1 year after surgery, together this makes long-term outcomes of cardiac surgery difficult to monitor. Further, traditional research methods have yet to advance understanding of what causes early complications and why surgical interventions fail.

METHODS AND ANALYSIS

This prospective cohort study will characterise participants undergoing cardiac surgery at baseline, describe short-term, medium-term and long-term health outcomes postoperatively and collect tissue samples.All eligible adult patients undergoing cardiac surgery at the Bristol Heart Institute, UK will be approached for consent. Recruitment is expected to continue for up to 10 years resulting in the largest cohort of cardiac patients reported to date. Blood, urine and waste tissue samples will be collected during admission. Samples, along with anonymised data, will be used to investigate outcomes and inform predictive models of complications associated with cardiac surgery.Data about the surgical admission will be obtained from hospital databases and medical notes. Participants may be monitored up to 5 years postoperatively using data obtained from NHS digital. Participants will complete health questionnaires 3 months and 12 months postoperatively.The analysis of data and tissue samples to address specific research questions will require separate research protocols and ethical approval.

ETHICS AND DISSEMINATION

This study was approved by the East Midlands Nottingham 2 Research Ethics Committee.Findings will be disseminated through peer-reviewed publications and presentation at national and international meetings. Participants will be informed of results in annual newsletters.

TRIAL REGISTRATION NUMBER

ISRCTN90204321.

Gene Dose-Dependent and Additive Effects of ABCG2 rs2231142 and SLC2A9 rs3733591 Genetic Polymorphisms on Serum Uric Acid Levels

This study aimed to evaluate whether the single nucleotide polymorphisms of ATP-binding cassette subfamily G member 2 (ABCG2) and solute carrier family 2 member 9 (SLC2A9) affect individual blood uric acid levels using pyrosequencing. ABCG2 (rs2231142, rs72552713, rs2231137), SLC2A9 (rs3734553, rs3733591, rs16890979), and individual uric acid levels were prospectively analyzed in 250 healthy young Korean male participants. Prominent differences in uric acid levels of the alleles were observed in the SLC2A9 rs3733591 polymorphism: wild-type (AA) vs. heterozygote (AG), 0.7 mg/dL (p < 0.0001); AA vs. mutant type (GG), 1.32 mg/dL (p < 0.0001); and AG vs. GG, 0.62 mg/dL (p < 0.01). In ABCG2 single nucleotide polymorphisms (SNPs), the statistically significant differences in uric acid levels were only found in rs2231142 between CC vs. AA (1.06 mg/dL; p < 0.001), and CC vs. CA (0.59 mg/dL; p < 0.01). Serum uric acid levels based on the ABCG2 and SLC2A9 diplotype groups were also compared. The uric acid levels were the lowest in the CC/AA diplotype and highest in the AA/AG diplotype. In addition, the SNP SLC2A9 rs3733591 tended to increase the uric acid levels when the ABCG2 rs2231142 haplotypes were fixed. In conclusion, both the ABCG2 rs2231142 and SLC2A9 rs3733591 polymorphisms may additively elevate blood uric acid levels.

Potential Mediators of Causal Associations of Circulating Triglycerides With Blood Pressure: Evidence From Genetic and Observational Data

Background:

Existing evidence indicates that elevated triglycerides may affect blood pressure, but the underlying mechanisms are not fully understood. Herein, we aim to identify the intermediaries of associations of triglyceride with systolic blood pressure and diastolic blood pressure using the Mendelian randomization (MR) framework.

Methods:

Triglyceride-associated single nucleotide polymorphisms were extracted and used to match phenotypes in PhenoScanner. From the broad spectrum of possible triglyceride-associated traits, potential mediators linking triglyceride to blood pressure were screened out by MR and MR-based mediation analysis. Moreover, cross-sectional observational data of 206 341 adults were used to validate the mediators identified at the genetic level.

Results:

Among the nearly 100 raw phenotypes matched by 313 triglyceride-associated single nucleotide polymorphisms, 39 traits were filtered and integrated into subsequent analysis. By further filtering using MR analysis, only pulse rate and lymphocyte count (LC) were identified as independent mediators. MR-based mediation analysis showed that genetically predicted LC could mediate 9.2% of the association of triglyceride with systolic blood pressure; genetically predicted pulse rate and LC could mediate 18.3% and 17.6% of the association of triglyceride with DBP, respectively. Observational data also support the mediating role of pulse rate and LC.

Conclusions:

The current findings highlighted the mediating role of pulse rate and LC on the causal pathway from triglyceride to blood pressure and may contribute to a better understanding of the pathogenic mechanism by which high triglyceride affects other cardiometabolic factors.

Assessing the causal relationships between gout and hypertension: a bidirectional Mendelian randomisation study with coarsened exposures

Objectives

Observational studies have demonstrated associations between gout and hypertension, but whether they are causal remains unclear. Our work aims to assess the causal relationship between gout and hypertension.

Methods

We obtained genetic information from the Taiwan Biobank, including 88,347 participants and 686,439 single-nucleotide polymorphisms (SNPs). A novel model of Mendelian randomisation (MR) with coarsened exposures was used to examine the causality between the liability of gout on hypertension and vice versa, using 4 SNPs associated with gout and 10 SNPs associated with hypertension after removal of SNPs associated with measured confounders. The binary exposure (gout/hypertension) can be considered a coarsened approximation of a latent continuous trait. The inverse-variance weighted (IVW) and polygenic risk score (PRS) methods were used to estimate effect size. The MR analysis with coarsened exposures was performed with and without adjustments for covariates.

Results

Of the 88,347 participants, 3253 (3.68%) had gout and 11,948 (13.52%) had hypertension (men, 31.9%; mean age 51.1 [SD, 11.1] years). After adjusting to measured confounders, MR analysis with coarsened exposures showed a significant positive causal effect of the liability of gout on hypertension in both the IVW method (relative risk [RR], 1.10; 95% confidence interval [CI], 1.03–1.19; p = 0.0077) and the PRS method (RR, 1.10; 95% CI, 1.02–1.19; p = 0.0092). The result of causality was the same before and after involving measured confounders. However, there was no causal effect of the liability of hypertension on gout.

Conclusions

In this study, we showed that the liability of gout has a causal effect on hypertension, but the liability of hypertension does not have a causal effect on gout. Adequate management of gout may reduce the risk of developing hypertension.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-022-02933-4.

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.

Synergistic Interaction between Hyperuricemia and Abdominal Obesity as a Risk Factor for Metabolic Syndrome Components in Korean Population

BACKGROUND

The present study investigated the role of synergistic interaction between hyperuricemia and abdominal obesity as a risk factor for the components of metabolic syndrome.

METHODS

We performed a cross-sectional study using the data of 16,094 individuals from the seventh Korean National Health and Nutrition Examination Survey (2016 to 2018). The adjusted odds ratios of metabolic syndrome and its components were analyzed by multivariate logistic regression analysis. The presence of synergistic interaction between hyperuricemia and abdominal obesity was evaluated by calculating the additive scales-the relative excess risk due to interaction, attributable proportion due to interaction, and synergy index (SI).

RESULTS

There was a synergistic interaction between hyperuricemia and abdominal obesity in hypertriglyceridemia (men: SI, 1.39; 95% confidence interval [CI], 1.01 to 1.98; women: SI, 1.61; 95% CI, 1.02 to 2.69), and low high-density lipoprotein cholesterol (HDL-C) (men: SI, 2.03; 95% CI, 1.41 to 2.91; women: SI, 1.70; 95% CI, 1.05 to 2.95). There was no significant synergistic interaction between hyperuricemia and abdominal obesity for the risk of high blood pressure (men: SI, 1.22; 95% CI, 0.85 to 1.77; women: SI, 1.53; 95% CI, 0.79 to 2.97), and hyperglycemia (men: SI, 1.03; 95% CI, 0.72 to 1.47; women: SI, 1.39; 95% CI, 0.75 to 2.57).

CONCLUSION

Hyperuricemia and abdominal obesity synergistically increased the risk of hypertriglyceridemia and low HDL-C in both sexes.

Weak Association Between Genetic Markers of Hyperuricemia and Cardiorenal Outcomes: Insights From the STANISLAS Study Cohort With a 20-Year Follow-Up

Background Hyperuricemia is associated with poor cardiovascular outcomes, although it is uncertain whether this relationship is causal in nature. This study aimed to: (1) assess the heritability of serum uric acid (SUA) levels, (2) conduct a genome-wide association study on SUA levels, and (3) investigate the association between certain single-nucleotide polymorphisms and target organ damage. Methods and Results The STANISLAS (Suivi Temporaire Annuel Non-Invasif de la Santé des Lorrains Assurés Sociaux) study cohort is a single-center longitudinal cohort recruited between 1993 and 1995 (visit 1), with a last visit (visit 4 [V4]) performed ≈20 years apart. Serum lipid profile, SUA, urinary albumin/creatinine ratio, estimated glomerular filtration rate, 24-hour ambulatory blood pressure monitoring, transthoracic echocardiography, pulse wave velocity, and genotyping for each participant were assessed at V4. A total of 1573 participants were included at V4, among whom 1417 had available SUA data at visit 1. Genome-wide association study results highlighted multiple single-nucleotide polymorphisms on the SLC2A9 gene linked to SUA levels. Carriers of the most associated mutated SLC2A9 allele (rs16890979) had significantly lower SUA levels. Although SUA level at V4 was highly associated with diabetes, prediabetes, higher body mass index, CRP (C-reactive protein) levels, estimated glomerular filtration rate variation (visit 1-V4), carotid intima-media thickness, and pulse wave velocity, rs16890979 was only associated with higher carotid intima-media thickness. Conclusions Our findings demonstrate that rs16890979, a genetic determinant of SUA levels located on the SLC2A9 gene, is associated with carotid intima-media thickness despite significant associations between SUA levels and several clinical outcomes, thereby lending support to the hypothesis of a link between SUA and cardiovascular disease.

Uric Acid and Oxidative Stress-Relationship with Cardiovascular, Metabolic, and Renal Impairment

Background: The connection between uric acid (UA) and renal impairment is well known due to the urate capacity to precipitate within the tubules or extra-renal system. Emerging studies allege a new hypothesis concerning UA and renal impairment involving a pro-inflammatory status, endothelial dysfunction, and excessive activation of renin–angiotensin–aldosterone system (RAAS). Additionally, hyperuricemia associated with oxidative stress is incriminated in DNA damage, oxidations, inflammatory cytokine production, and even cell apoptosis. There is also increasing evidence regarding the association of hyperuricemia with chronic kidney disease (CKD), cardiovascular disease, and metabolic syndrome or diabetes mellitus. Conclusions: Important aspects need to be clarified regarding hyperuricemia predisposition to oxidative stress and its effects in order to initiate the proper treatment to determine the optimal maintenance of UA level, improving patients’ long-term prognosis and their quality of life.

No Evidence for a Causal Link between Serum Uric Acid and Nonalcoholic Fatty Liver Disease from the Dongfeng-Tongji Cohort Study

Background and Aims

Elevated serum uric acid (SUA) is associated with an increased risk of nonalcoholic fatty liver disease (NAFLD); however, whether this association is causal is undetermined.

Methods

Each participant from the Dongfeng-Tongji cohort study based on 27,009 retirees was interviewed face-to-face following a clinical examination. Covariance, logistic regression analysis, and instrumental variables were used to assess associations between SUA and (severity of) NAFLD and the causal link.

Results

Among 8,429 subjects free of NAFLD at baseline, 2,007 participants developed NAFLD after 5 years of follow-up. The multivariable-adjusted odds ratio (OR) for NAFLD for individuals in the fourth quartile of SUA level versus those in the first was 1.71 (95% CI: 1.45-2.01, P for trend <0.001) and was more dramatic in women or normal-weight persons. Furthermore, SUA was materially associated with greater mean markers of hepatic necroinflammation and greater probabilities of fibrosis. In genetic analyses, both single nucleotide polymorphisms (rs11722228 to SLC2A9 and rs2231142 to ABCG2) were pronouncedly associated with increased SUA concentrations, ranging from 0.19 to 0.22 mg/dl. No significant associations were observed between SNPs and potential confounders. No association was observed between the SUA-increasing allele and NAFLD, with an OR of 0.98 (95% CI: 0.90-1.08) per genetic score. This was not significantly different (P = 0.25) from what was expected (1.03, 95% CI: 1.03-1.03).

Conclusions

SUA was positively associated with NAFLD incidence especially in female and normal-weight individuals and the suspected progression risk of newly developed NAFLD. However, the Mendelian randomization analyses lend no causal evidence, suggesting high SUA as a marker and not a cause of NAFLD.

Joint Effect of Beer, Spirits Intake, and Excess Adiposity on Hyperuricemia Among Chinese Male Adults: Evidence From the China National Health Survey

Alcohol intake and excess adiposity are associated with serum uric acid (SUA), but their interaction effect on hyperuricemia (HUA) remains unclear. Using data from the China National Health Survey (CNHS) (2012-2017), we analyzed the additive interaction of beer, spirits intake, excess adiposity [measured by body mass index (BMI), body fat percentage (BFP), and visceral fat index (VFI)] with HUA among male participants aged 20-80 from mainland China. The relative excess risk due to interaction (RERI), the attributable proportion due to interaction (AP), and the synergy index (SI) were calculated to assess the interaction effect on the additive scale. Both RERI and AP larger than 0 and SI larger than 1 indicate a positive additive interaction. Among 12,592 male participants, the mean SUA level was 367.1 ± 85.5 μmol/L and 24.1% were HUA. Overweight/obese men who were presently drinking spirits had an odds ratio (OR) of 3.20 (95%CI: 2.71-3.79) than the never drink group, with RERI, AP, and SI of 0.45 (95%CI: 0.08-0.81), 0.14 (95%CI: 0.03-0.25), and 1.25 (95%CI: 1.02-1.54), respectively. However, although combined exposures on beer intake and excess adiposity had the highest OR compared with no beer intake and nonobese participants, there was no additive interaction, with RERI, AP, and SI in the overweight/obesity and the beer intake group of 0.58 (-0.41-1.57), 0.17 (-0.08-0.41), and 1.30 (0.85-1.97), respectively. Other excess adiposity indexes revealed similar estimates. Our findings suggested that the exposures of both excess adiposity and alcohol drink could result in an additive interaction effect on HUA: the combined risk of excess adiposity with spirits intake but not with beer was greater than the sum of the effects among Chinese male adults.

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.

Excess comorbidities in gout: the causal paradigm and pleiotropic approaches to care

Gout is a common hyperuricaemic metabolic condition that leads to painful inflammatory arthritis and a high comorbidity burden, especially cardiometabolic-renal (CMR) conditions, including hypertension, myocardial infarction, stroke, obesity, hyperlipidaemia, type 2 diabetes mellitus and chronic kidney disease. Substantial advances have been made in our understanding of the excess CMR burden in gout, ranging from pathogenesis underlying excess CMR comorbidities, inferring causal relationships from Mendelian randomization studies, and potentially discovering urate crystals in coronary arteries using advanced imaging, to clinical trials and observational studies. Despite many studies finding an independent association between blood urate levels and risk of incident CMR events, Mendelian randomization studies have largely found that serum urate is not causal for CMR end points or intermediate risk factors or outcomes (such as kidney function, adiposity, metabolic syndrome, glycaemic traits or blood lipid concentrations). Although limited, randomized controlled trials to date in adults without gout support this conclusion. If imaging studies suggesting that monosodium urate crystals are deposited in coronary plaques in patients with gout are confirmed, it is possible that these crystals might have a role in the inflammatory pathogenesis of increased cardiovascular risk in patients with gout; removing monosodium urate crystals or blocking the inflammatory pathway could reduce this excess risk. Accordingly, data for CMR outcomes with these urate-lowering or anti-inflammatory therapies in patients with gout are needed. In the meantime, highly pleiotropic CMR and urate-lowering benefits of sodium-glucose cotransporter 2 (SGLT2) inhibitors and key lifestyle measures could play an important role in comorbidity care, in conjunction with effective gout care based on target serum urate concentrations according to the latest guidelines.

The Serum Uric Acid to Serum Creatinine Ratio is an Independent Risk Factor for Diabetic Kidney Disease

PURPOSE

A retrospective study was designed to evaluate whether the serum uric acid to serum creatinine ratio (SUA/SCr) can be used as an indicator of diabetic kidney disease (DKD) and macroangiopathy in patients with type 2 diabetes mellitus (T2DM).

PATIENTS AND METHODS

We screened 2227 patients diagnosed with T2DM, and 450 patients were finally included. They were assigned to three groups based on the tertile of SUA/SCr (Group Tertile 1, Tertile 2, Tertile 3). Demographic information and biochemical parameters were collected from Electronic Patient Record (EPR).

RESULTS

The estimated glomerular filtration rate (eGFR) values were lowest in Group Tertile 1 and highest in Group Tertile 3 (P < 0.05). There was no significant difference in urinary albumin creatinine ratio (UACR) among the three groups (P > 0.05). Partial correlation analyses revealed that SUA/SCr levels were significantly and positively correlated with eGFR, SUA, body mass index, gamma-glutamyl transpeptidase, alanine transaminase, triglycerides, C-peptide, high-density lipoprotein cholesterol and fatty liver, while they were negatively correlated with SCr, blood urea nitrogen, cystatin-c, age, male sex, DM duration and hypertension history (P < 0.05). Logistic regression analysis revealed that SUA/SCr was an independent risk factor for eGFR < 60 mL/min/1.73 m² (P < 0.05). The ROC curve showed that the cutoff value of SUA/SCr for the identification of eGFR < 60 mL/min/1.73 m² was 3.434. In patients with normal UACR, SUA/SCr levels of patients with eGFR < 60 mL/min/1.73 m² were lower than those with eGFR ≥ 60 mL/min/1.73 m² (P < 0.05). Regression analysis did not show SUA/SCr associate to macrovascular disease after adjusting for confounding factors.

CONCLUSION

SUA/SCr is an independent risk factor for DKD in patients with T2DM and may be helpful for identifying normoalbuminuric DKD.

Metabolic Factors Mediate the Association Between Serum Uric Acid to Serum Creatinine Ratio and Cardiovascular Disease

Background

The serum uric acid/serum creatinine ratio (SUA/SCr), which represents renal function‐normalized SUA, is associated with diverse adverse outcomes. The aim of this study was to investigate the association between SUA/SCr and cardiovascular disease (CVD), and determine whether and to what extent this association is mediated by cardiometabolic factors.

Methods and Results

This prospective study enrolled 96 378 participants from the Kailuan study without stroke and myocardial infarction at baseline (2006). Cox proportional hazard models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs). Mediation analyses were conducted to separately explore the mediating effects of cardiometabolic factors on the association between SUA/SCr and CVD. During median follow up of 11.01 years, 6315 (6.55%) individuals developed incident CVD. After adjustment for potential confounders, the highest quartile of SUA/SCr was associated with the highest risk of CVD (HR, 1.15; 95% CI, 1.07–1.23), stroke (HR, 1.16; 95% CI, 1.07–1.26), ischemic stroke (HR, 1.12; 95% CI, 1.02–1.22), and hemorrhagic stroke (HR, 1.36; 95% CI, 1.11–1.65), but not with myocardial infarction (HR, 1.07; 95% CI, 0.92–1.25). The association was consistent across different degrees of kidney function and glucose tolerance statuses. Additionally, the association between high SUA/SCr and CVD was partially mediated by triglycerides (30.74%), body mass index (BMI) (19.52%), total cholesterol (15.06%), hs‐CRP (high‐sensitivity C‐reactive protein) (13.06%), diastolic blood pressure (11.75%), and blood glucose (−16.38%).

Conclusions

SUA/SCr and CVD were positively associated. Furthermore, this association was partially mediated through blood lipids, BMI, blood pressure, hs‐CRP, and blood glucose.

Obesity-Induced Insulin Resistance Is Mediated by High Uric Acid in Obese Children and Adolescents

Objective

This study aimed to evaluate whether serum uric acid (SUA) plays a mediating role in the development of insulin resistance (IR) in obese children and adolescents.

Methods

A total of 369 participants aged 4-17 years with obesity who attended the Nutrition Outpatient Clinic for Obesity at Xinhua Hospital from January 2012 to January 2019 were recruited for this retrospective study. We classified participants into two groups on the basis of HOMA-IR values: the low HOMA-IR group (< 3.16) (n = 222) and the high HOMA-IR group (≥ 3.16) (n = 147).

Results

The univariate analysis found that the high HOMA-IR group had higher BMI, SUA, and fasting insulin (FINS) (P < 0.05). Multiple linear regression analysis and mediating effect analysis indicated that body mass index (BMI) could directly regulate FINS and HOMA-IR (both P < 0.05). The results from the mediating effect analysis found that UA partially played an indirect role in the link between BMI, FINS and HOMA-IR (both P < 0.05) but had no effect on fasting blood glucose (P > 0.05).

Conclusions

SUA should be investigated in obesity and plays a partial mediating role in insulin resistance induced by obesity in obese children and adolescents.

Impact of adiposity on risk of female gout among those genetically predisposed: sex-specific prospective cohort study findings over >32 years

OBJECTIVES

To evaluate the joint (combined) association of excess adiposity and genetic predisposition with the risk of incident female gout, and compare to their male counterparts; and determine the proportion attributable to body mass index (BMI) only, genetic risk score (GRS) only, and to their interaction.

METHODS

We prospectively investigated potential gene-BMI interactions in 18 244 women from the Nurses' Health Study and compared with 10 888 men from the Health Professionals Follow-Up Study. GRS for hyperuricaemia was derived from 114 common urate-associated single nucleotide polymorphisms.

RESULTS

Multivariable relative risk (RR) for female gout was 1.49 (95% CI 1.42 to 1.56) per 5 kg/m² increment of BMI and 1.43 (1.35 to 1.52) per SD increment in the GRS. For their joint association of BMI and GRS, RR was 2.18 (2.03 to 2.36), more than the sum of each individual factor, indicating significant interaction on an additive scale (p for interaction <0.001). The attributable proportions of joint effect for female gout were 42% (37% to 46%) to adiposity, 37% (32% to 42%) to genetic predisposition and 22% (16% to 28%) to their interaction. Additive interaction among men was smaller although still significant (p interaction 0.002, p for heterogeneity 0.04 between women and men), and attributable proportion of joint effect was 14% (6% to 22%).

CONCLUSIONS

While excess adiposity and genetic predisposition both are strongly associated with a higher risk of gout, the excess risk of both combined was higher than the sum of each, particularly among women.

Association between hyperuricemia and hypertension: a case-control study

OBJECTIVE

The aim of this study was to evaluate the association between hyperuricemia and systemic arterial hypertension.

METHODS

This was a case-control study where individuals aged >18 years were included, who were divided into hypertensive and non-hypertensive groups, excluding those with incomplete information in medical records or with the chronic kidney disease epidemiology collaboration <60 mL/min/1.73 m³. Systemic arterial hypertension was categorized as a dependent variable, while the independent variables were hyperuricemia (i.e., primary variable), sex, education, the practice of physical activity, alcoholism, smoking, diabetes mellitus, chronic kidney disease, a family history of systemic arterial hypertension, age, isolated hyperlipidemia, and mixed hyperlipidemia. Statistical analysis included the univariate and multivariate data analysis, performed by adjusting the logistic regression models using the software R (R Core Team [2018]).

RESULTS

Out of 103 patients evaluated, 75 patients were included in this study. In hypertensive patients, hyperuricemia was more frequent (p=0.029), being present in 18.9% individuals. In the univariate analysis, a statistically significant association was found between hyperuricemia and systemic arterial hypertension (OR 10.9; 95%CI 1.29-1420.0; p=0.023); however, in the multivariate analysis, when adjustment was made for age, the only control variable that persisted in the model, this association ceased to be significant (OR 8.5; 95%CI 0.87-1157.0; p=0.070).

CONCLUSIONS

There was no independent association between hyperuricemia and systemic arterial hypertension. The latter was associated with diabetes mellitus, chronic kidney disease, and age.

Gout, Hyperuricaemia and Crystal-Associated Disease Network (G-CAN) common language definition of gout

Objective

To develop a Gout, Hyperuricaemia and Crystal-Associated Disease Network (G-CAN) common language definition of gout, with the goal of increasing public understanding and awareness, and ensure consistent and understandable messages about gout.

Methods

A G-CAN working group that included patients, physicians and nongovernmental organisation (NGO) representatives was formed to develop a common language definition of gout for use with the public, media, healthcare providers and stakeholders. A literature search and interviews with patients, healthcare workers and stakeholders informed development of the definition. Following consultation with G-CAN members and partners, the definition was endorsed by the G-CAN board.

Results

The G-CAN common language definition of gout describes the epidemiology, pathophysiology, symptoms and impact, risk factors, comorbidities, management and healthcare and workforce considerations. Detailed information is provided to support the content of the definition. After the publication of the English-language version, the definition will be available for translation into other languages by G-CAN members.

Conclusion

G-CAN has developed a concise and easily understandable statement describing gout in language that can be used in conversations with the lay public, media, NGOs, funders, healthcare providers and other stakeholders.

Dietary and Lifestyle-Centered Approach in Gout Care and Prevention

PURPOSE OF REVIEW

We aim to provide a comprehensive review of the available literature to inform dietary recommendations for patients with gout and hyperuricemia that have the potential to simultaneously lower serum urate and reduce gout morbidity while addressing gout's cardiometabolic comorbidities holistically.

RECENT FINDINGS

The global burden of gout is rising worldwide, particularly in developed nations as well as in women. Patients with gout are often recommended to follow a low-purine (i.e., low-protein) diet to avoid purine-loading. However, such an approach may lead to increased consumption of unhealthy carbohydrates and fats, which in turn contributes to metabolic syndrome and subsequently raises serum urate levels and leads to adverse cardiovascular outcomes. On the other hand, several well-established diets for cardiometabolic health, such as the Mediterranean and Dietary Approaches to Stop Hypertension (DASH) diets, in combination with weight loss for those who are overweight or obese, also have beneficial effects on relevant gout endpoints. It is important to recognize not only the direct effect of diet on hyperuricemia and gout, but its mediated effect through obesity and insulin resistance. Thus, several preeminent healthy dietary patterns that have proven benefits in cardiometabolic health have the power to holistically address not only gout morbidity but also its associated comorbidities that lead to premature mortality among patients with gout.

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.

Changes in serum uric acid and the risk of cardiovascular disease and all-cause mortality in the general population

BACKGROUND AND AIM

Longitudinal evidence on change in serum (SUA) with risk of cardiovascular disease (CVD) and all-cause mortality is limited, as many prior studies focused on baseline SUA. Further, the optimal threshold range of SUA change is unclear.

METHODS AND RESULTS

A total of 63,127 participants without history of CVD were enrolled. Change in SUA was determined by the difference of SUA levels between 2006 and 2010, which divided by baseline SUA was percent change in SUA. Multivariable Cox proportional hazards models were used to calculated the hazard ratios (HRs) and 95% confidence intervals (CIs). Our analysis also included restricted cubic spline model and three-piecewise Cox proportion hazards model to address the non-linearity between percent change in SUA and outcomes. During a median follow-up of 7.04 years, 3341 CVD and 3238 deaths occurred. We did not observed a significant association between changes in SUA and CVD. However, changes in SUA at extreme were associated with higher risk of all-cause mortality, the HRs (95% CIs) were 1.15 (1.02-1.29) and 1.20 (1.06-1.35) in the first and fifth quintile group, compared with the third quintile group. We further found a U-shaped association between percent change in SUA and all-cause mortality, and the optimal range was within 20%.

CONCLUSIONS

Changes in SUA at extreme were risk factors for all-cause mortality, but not for CVD in the general population. The findings are relevant for role of SUA in the management of CVD risk and may contribute to improve identification of patients at higher risk.

Second-Hand Smoke and Its Synergistic Effect with a Body-Mass Index of >24.9 kg/m2 Increase the Risk of Gout Arthritis in Indonesia

To analyze the association between smoking status (active smoking and exposure to Second-Hand Smoking (SHS)) and the synergistic effect of smoking status and BMI with gout risk, a community-based case-control design was undertaken among 385 participants, including 304 healthy controls and 81 gout patients from seven community health services. Adjusted Odd Ratios (AORs) and 95% Confidence Interval (CIs) of gout for active smoking and SHS were 3.26 (95% CI = 1.07~9.90) and 4.67 (95% CI = 2.18~10.00) compared to non-smokers. Time-dependent manner of active smoking and SHS significantly increased gout risk with AORs and 95% CIs of 5.95 (1.41~25.03) and 10.12 (3.51~29.14). Dose-dependency of active smokers and SHS showed AORs and 95% CIs of 5.15 (1.28~20.63) and 4.37 (1.33~14.28). Smoking 20 cigarettes (one pack) per day for one year is equivalent to one pack-year. Active smoking >20 pack-year and SHS > 26.5 pack-year increased gout risk with AORs and 95% CIs of 7.18 (1.53~33.67) and 9.95 (3.64~27.22). Participants who smoked (active smoking and SHS) and with Body Mass Index (BMI) of > 24.9 kg/m2 synergistically increased gout risk, with an AOR of 9.65 and 95% CI of 3.25~28.65, compared to BMI ≤ 24.9 kg/m2 and non-smoker. Smoking status (active smoking and SHS) and the synergistic effect of smoking status and BMI increased gout risk in Indonesia.

The importance of including uric acid in the definition of metabolic syndrome when assessing the mortality risk

Introduction

Serum uric acid (SUA) has been depicted as a contributory causal factor in metabolic syndrome (MS), which in turn, portends unfavourable prognosis.

Aim

We assessed the prognostic role of SUA in patients with and without MS.

Methods

We used data from the multicentre Uric Acid Right for Heart Health study and considered cardiovascular mortality (CVM) as death due to fatal myocardial infarction, stroke, sudden cardiac death, or heart failure.

Results

A total of 9589 subjects (median age 58.5 years, 45% males) were included in the analysis, and 5100 (53%) patients had a final diagnosis of MS. After a median follow-up of 142 months, we observed 558 events. Using a previously validated cardiovascular SUA cut-off to predict CVM (> 5.1 mg/dL in women and 5.6 mg/dL in men), elevated SUA levels were significantly associated to a worse outcome in patients with and without MS (all p < 0.0001) and provided a significant net reclassification improvement of 7.1% over the diagnosis of MS for CVM (p = 0.004). Cox regression analyses identified an independent association between SUA and CVM (Hazard Ratio: 1.79 [95% CI, 1.15–2.79]; p < 0.0001) after the adjustment for MS, its single components and renal function. Three specific combinations of the MS components were associated with higher CVM when increasing SUA levels were reported, and systemic hypertension was the only individual component ever-present (all p < 0.0001).

Conclusion

Increasing SUA levels are associated with a higher CVM risk irrespective of the presence of MS: a cardiovascular SUA threshold may improve risk stratification.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s00392-021-01815-0.

Obesity interacts with hyperuricemia on the severity of non-alcoholic fatty liver disease

Background

A series of evidence revealed that body mass index was an important confounding factor in the research of uric acid and ischemic heart disease/hypertension. The objective of this study was to investigate whether obesity status can modify the association between serum uric acid and the severity of liver damage in NAFLD, and the possible interactive effect of hyperuricemia and obesity.

Methods

We conducted a cross-sectional study in a total of 557 ultrasound diagnosed-NAFLD. The hepatic steatosis and liver fibrosis were quantitatively evaluated by transient elastography. Hyperuricemia was defined as serum uric acid > 420 μmol/L in men, > 360 μmol/L in women and obesity was defined as body mass index ≥ 25 kg/m². The adjusted OR values of hyperuricemia and obesity were analyzed by multivariate logistic regression analysis, and the additive model was used to investigate the possible interactive effect.

Results

Multivariate regression analysis showed that hyperuricemia was associated with serious hepatic steatosis (1.74[1.09–2.79]) and elevated ALT (2.17[1.38–3.41]), but not with advanced fibrosis (1.61[0.91–2.85]). The association was further investigated in different BMI group. Hyperuricemia was associated with higher odds of serious hepatic steatosis (2.02[1.14–3.57]) and elevated ALT (2.27[1.37–3.76]) only in obese NAFLD, not in non-obese subjects. Similarly, patients with hyperuricemia had higher odds of advanced fibrosis in obese subjects (2.17[1.13–4.18]), not in non-obese subjects (0.60[0.14–2.70]). Furthermore, there was an additive interaction between hyperuricemia and obesity on the odds of serious hepatic steatosis (AP: 0.39[0.01–0.77]) and advanced fibrosis. (AP: 0.60[0.26–0.95]).

Conclusions

Hyperuricemia and obesity had a significantly synergistic effect on the hepatic steatosis and fibrosis. Thus, management of uric acid may need to be targeted in obese NAFLD.

Uric Acid and Hypertension: Prognostic Role and Guide for Treatment

The relationship between serum uric acid (SUA) and hypertension has been a subject of increasing interest since the 1870 discovery by Frederick Akbar Mahomed. Several epidemiological studies have shown a strong association between high SUA levels and the presence or the development of hypertension. Genetic analyses have found that xanthine oxidoreductase (XOR) genetic polymorphisms are associated with hypertension. However, genetic studies on urate transporters and Mendelian randomization studies failed to demonstrate a causal relationship between SUA and hypertension. Results from clinical trials on the role of urate-lowering therapy in the management of patients with hypertension are not uniform. Our study sought to analyze the prognostic and therapeutic role of SUA in the hypertensive disease, from uric acid (UA) biology to clinical trials on urate-lowering therapies.