Hyperuricemia is associated with an increased prevalence of atrial fibrillation in hospitalized patients with type 2 diabetes

Progress of uric acid in cardiovascular disease

Due to the global prevalence of hyperuricemia (HUA), there is growing interest in research on uric acid (UA). HUA is a common condition that has various adverse consequences, including gout and kidney disease. However, recent studies have also implicated UA in the development of cardiovascular diseases (CVD) such as atrial fibrillation (AF) and coronary heart disease (CHD). Experimental and clinical research has extensively demonstrated the detrimental effects of elevated serum UA levels on cardiovascular health. Furthermore, serum UA levels have been identified as predictors of CVD outcomes following percutaneous coronary intervention (PCI) and catheter ablation. Additionally, the use of UA-lowering therapy holds important implications for the management of CVD. This review aims to consolidate the current evidence on the relationship between serum UA and CVD.

Association between serum uric acid levels and atrial fibrillation in different fasting glucose patterns: A case-control study

BACKGROUND

Previous studies have shown both dysglycaemia and hyperuricemia are associated with an increased risk of atrial fibrillation (AF), while the relationship between serum uric acid (SUA) levels and AF in different fasting glucose patterns (FBG) is unclear. Therefore, this study aimed to determine the association between SUA and AF in different FBG patterns.

METHODS

A total of 1840 patients in this case-control study were enrolled, including 920 AF patients and 920 controls. Patients were divided into three groups according to the different FBG patterns: normoglycemic, impaired fasting glucose (IFG), and diabetes mellitus (DM). Multivariate logistic regression models were performed to evaluate the relationship between SUA and AF in different FBG patterns. Pearson correlation analysis was used to explore the correlation between SUA and metabolic factors. Receiver operating characteristic (ROC) curve models indicated the diagnostic efficiency of SUA for diagnosing AF.

RESULTS

SUA was independently associated with AF after adjusting for all confounding factors in different FBG patterns(normoglycemic: OR=1.313, 95% CI:1.120-1.539; IFG: OR=1.386, 95% CI:1.011-1.898; DM: OR=1.505, 95% CI:1.150-1.970). Pearson's correlation analysis suggested that SUA in AF patients was correlated with several different metabolic factors in different FBG patterns (p<0.05). ROC curve analysis showed that SUA in the normoglycemic group combined with CHD and APOB [AUC: 0.906 (95% CI: 0.888-0.923)], in the IFG group combined with CHD and Scr [AUC: 0.863 (95% CI: 0.820-0.907)], in the DM group combined with CHD and SBP [AUC: 0.858 (95% CI: 0.818-0.898)] had the highest AUC for predicting AF.

CONCLUSION

Findings implied a significant association between SUA and AF in different FBG patterns and provide specific models combined with other factors (CHD, APOB, SCr, SBP), which might contribute to the diagnosis of AF.

Hyperuricemia is associated with an increased prevalence of ventricular tachycardia and fibrillation in patients with ST-elevation myocardial infarction after primary percutaneous coronary intervention

Background

Little is known about the association between hyperuricemia and ventricular tachycardia and fibrillation (VT/VF) in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI).

Methods

The data from a cohort of STEMI patients undergoing PPCI at our center from January 2013 to December 2018 were retrospectively analyzed. The endpoint of the study was the occurrence of VT/VF, including (1) non-sustained ventricular tachycardia (nsVT) on Holter monitoring; (2) sustained ventricular tachycardia (SVT)/VF on cardiac monitoring.

Results

Of the 634 patients included in the study, 147 (23.2%) of them had hyperuricemia. The occurrence of VT/VF after PPCI was significantly higher in patients with hyperuricemia (19.0 vs. 9.4%, p = 0.001) compared with those without hyperuricemia. Hyperuricemia was associated with a significantly higher risk of VF/VT (odds ratio (OR) 2.11; 95% CI 1.11–4.03; p = 0.024). The strength of this association remained statistically after adjustments for age, sex, history of hypertension, estimated glomerular filtration rate, hypersensitive C reactive protein, plasma natrium, peak troponin I, fasting glucose, B-type natriuretic peptides and VT/VF in PPCI (adjusted odds ratio 2.73; 95% CI 1.19–6.27; p = 0.018).

Conclusions

There is a significant association between hyperuricemia and increased prevalence of VT/VF in STEMI patients after PPCI, independently of multiple risk factors and potential confounders.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-022-02635-4.

New insights into the role of melatonin in diabetic cardiomyopathy

Diabetic cardiovascular complications and impaired cardiac function are considered to be the main causes of death in diabetic patients worldwide, especially patients with type 2 diabetes mellitus (T2DM). An increasing number of studies have shown that melatonin, as the main product secreted by the pineal gland, plays a vital role in the occurrence and development of diabetes. Melatonin improves myocardial cell metabolism, reduces vascular endothelial cell death, reverses microcirculation disorders, reduces myocardial fibrosis, reduces oxidative and endoplasmic reticulum stress, regulates cell autophagy and apoptosis, and improves mitochondrial function, all of which are the characteristics of diabetic cardiomyopathy (DCM). This review focuses on the role of melatonin in DCM. We also discuss new molecular findings that might facilitate a better understanding of the underlying mechanism. Finally, we propose potential new therapeutic strategies for patients with T2DM.

The Relationship between Uric Acid and the Development, Complication, and Prognosis of Atrial Fibrillation: The Views from a Clinical Study

A large number of studies suggest that uric acid (UA) is related to the occurrence, complications, and prognosis of atrial fibrillation (AF). However, the guidelines did not clearly elaborate on this issue. The current research results need to be summarized to analyze the association between UA and AF. This study found that in the current clinical research on the relationship between UA and AF, studies mainly focus on the development or complications of AF. A lot of repetitive work does not deepen awareness of this question. In contrast, studies investigating the effects of UA-lowering therapy on the management of AF are limited. The only reports deny the protective effect of UA-lowering therapy. For now, we suggest that UA is close to the occurrence and progression of AF; therefore, it may have important significance as a clinical marker. The role of UA-lowering therapy in the management of AF is one of the next key issues to be explored. It will be a meaningful topic to focus on the latest research on AF ablation and to conduct a secondary analysis to explore the prognostic impact of UA on the latest treatment methods for AF. Multiomics techniques may allow us to have a deeper understanding of the role of UA in AF management in the future.

Hyperuricemia Increases the Risk of Atrial Fibrillation: A Systematic Review and Meta-Analysis

Association between hyperuricemia (HUA) and atrial fibrillation (AF) remains unclear. We reviewed clinical evidence and aimed to determine whether hyperuricemia leads to a high risk of atrial fibrillation. Most studies were identified through databases online. Keywords used in literature search were hyperuricemia, atrial fibrillation, metabolic disorder, endocrine disorder, or uric acid. Three studies were provided by the authors. Literature search was performed without any data or language restriction. Observational studies, including cohort studies and cross-sectional studies, were used. Study type should be clearly defined. Cross-sectional studies should clearly introduce the sources of epidemiological data. Studies were excluded if with too many complications unrelated to AF enrolled. Data were independently extracted by three individuals. Data synthesis was conducted by R version 4.1.2. Prevalence of atrial fibrillation was the main outcome. Results of meta-analysis were presented as risk ratio (RR) for different prevalence of AF between individuals with and without HUA. All data included were obtained after follow-up work is completed. Data from 608,810 participants showed that patients with hyperuricemia were easier to suffer from atrial fibrillation (RR, 2.42; 95% CI, 1.24-3.03). And the meta-regressions suggested growth of linear proportion between the ratio of current drinkers and hyperuricemia (QM = 41.0069, P < 0.001). Subgroup analyses demonstrated consistent results in different countries. And design of the observational studies brought heterogeneity, but no uncertainties. Patients with hyperuricemia were easier to suffer from atrial fibrillation. Treatment of hyperuricemia or gout may bring potential benefits for AF patients.

Serum Uric Acid Levels and Risk of Rapid Decline of Estimated Glomerular Filtration Rate in Patients with Type 2 Diabetes: Findings from a 5-Year Prospective Cohort Study

This study investigated the association between serum uric acid (SUA) levels with rapid decline of the estimated glomerular filtration rate (eGFR) in type 2 diabetes (T2 DM) patients. A prospective cohort study was conducted in a community-based hospital in Vietnam. We followed 405 T2DM patients with normal kidney function for five years. Rapid progression of kidney function was defined as an average annual decrease of eGFR of at least 4 mL/min/1.73 m² and was found in 16.0% of patients. Patients in the SUA high tertile ( ≥6 mg/dL) had higher BMI (p = 0.004), lower HbA1c (p = 0.001), lower eGFR (p < 0.001) and higher rate of hypertension than low and middle tertile. After adjusting for age and sex, rapid progression of renal function was significantly associated with SUA level (OR = 1.22, 95% CI 1.02-1.45, p = 0.026). This association was marginally significant when more covariates were included in the model (OR = 1.20, 95% CI 0.99-1.46, p = 0.065). However, the association between tertiles of SUA and rapid decline of eGFR was not statistically significant. This study demonstrates neither a strong significant association between SUA and rapid decline of eGFR nor evidence to refuse the role of SUA levels in the increased risk of renal function decline in in T2DM patients.

Relationship between serum uric acid levels and different types of atrial fibrillation: An updated meta-analysis

AIM

Increasing evidence supports the hypothesis that high serum uric acid (SUA) levels are related to atrial fibrillation (AF). However, the incidence of AF in patients with hyperuricemia and SUA levels in different types of AF is not entirely clear. This meta-analysis was designed to evaluate the relationship between SUA and incidence of AF, and the variation in SUA levels in different types of AF.

DATA SYNTHESIS

Relevant reports were searched for in Embase, PubMed and the Cochrane Library. A fixed-effects model combining relative risk (RR) and the corresponding 95% confidence interval (95% CI) was used to evaluate the correlation between SUA and AF. The standardized mean differences (SMDs) of SUA values were calculated using a random-effects model to evaluate the differences in SUA levels among different types of AF. A total of 31 studies with 504,958 participants were included in this research. The results from 8 cohort studies showed that high SUA levels significantly increased the incidence of AF [RR (95% CI): 1.92 (1.68-2.20); P < 0.01]. The results from 29 studies revealed that SUA levels elevated in patients with AF [SMD (95% CI): 0.55 (0.43-0.66); P < 0.001]. Meanwhile, SUA levels in new-onset AF [SMD (95%CI): 0.24 (0.10-0.38); P = 0.001], paroxysmal AF [SMD (95%CI): 0.52 (0.33-0.72); P < 0.001] and persistent AF [SMD (95%CI): 1.23 (0.98-1.48); P < 0.001] were significantly higher than that in patients without AF.

CONCLUSIONS

High SUA levels had an obvious correlation with the occurrence rate of AF. In addition, SUA levels were significantly different among patients with new-onset, paroxysmal and persistent AF.

Vitamin D supplementation is associated with serum uric acid concentration in patients with prediabetes and hyperuricemia

Aims

Vitamin D deficiency is associated with a number of noncommunicable conditions. We conducted a randomised controlled trial to determine the effect of vitamin D supplementation on serum uric acid concentration in patients with prediabetes, in whom hyperuricaemia is common.

Methods

Seventy-one volunteers (35–80 years), with impaired fasting glucose and/or impaired glucose tolerance were randomised to three groups, vitamin D₃, vitamin D₂ and control, and followed for 12 months.

Results

After 12 weeks, vitamin D supplementation was associated with a reduction in serum uric acid concentration in participants with baseline uric acid concentration > 6 mg/dL, but no significant change was observed in controls. We then assessed the dose–response relationship between vitamin D supplementation and the change in serum uric acid concentration and found that the change in serum total 25-hydroxyvitamin D did not correlate with the change in serum uric acid that occurred during vitamin D supplementation. The factors associated with larger reductions in serum uric acid were a higher baseline serum uric acid and a larger increase in serum 1,25-dihydroxyvitamin D.

Conclusions

Vitamin D supplementation lowers serum uric acid in prediabetic patients with hyperuricaemia, and supplementation might be considered to help alleviate hyperuricaemia in these patients.

Cardiovascular benefits of sodium-glucose cotransporter 2 inhibitors in diabetic and nondiabetic patients

Sodium-glucose cotransporter 2 inhibitors (SGLT2i) were developed as antidiabetic agents, but accumulating evidence has shown their beneficial effects on the cardiovascular system. Analyses of the EMPA-REG OUTCOME trial (Empagliflozin Cardiovascular Outcome Event Trial in Type 2 Diabetes Mellitus Patients) suggested that these benefits are independent of glycemic control. Several large-scale outcome trials of SGLT2i also showed cardiovascular benefits in nondiabetic patients, strengthening this perspective. Extensive animal and clinical studies have likewise shown that mechanisms other than the antihyperglycemic effect underlie the cardiovascular benefits. Recent clinical guidelines recommend the use of SGLT2i in patients with type 2 diabetes mellitus and cardiovascular diseases because of the proven cardiovascular protective effects. Since the cardiovascular benefits are independent of glycemic control, the therapeutic spectrum of SGLT2i will likely be extended to nondiabetic patients.

The Key Role of Uric Acid in Oxidative Stress, Inflammation, Fibrosis, Apoptosis, and Immunity in the Pathogenesis of Atrial Fibrillation

Atrial fibrillation (AF) is a highly prevalent cardiac arrhythmia that leads to numerous adverse outcomes including stroke, heart failure, and death. Hyperuricemia is an important risk factor that contributes to atrium injury and AF, but the underlying molecular mechanism remains to be elucidated. In this review, we discussed the scientific evidence for clarifying the role of hyperuricemia in the pathogenesis of AF. Experimental and Clinical evidence endorse hyperuricemia as an independent risk factor for the incidence of AF. Various in vivo and in vitro investigations showed that hyperuricemia might play a critical role in the pathogenesis of AF at different UA concentrations through the activation of oxidative stress, inflammation, fibrosis, apoptosis, and immunity.

Serum uric acid and incident atrial fibrillation: A systematic review and dose-response meta-analysis

The exposure-effect association between serum uric acid and atrial fibrillationis not well known. We conduct a meta-analysis to quantitatively examine the exposure-effect relationship between serum uric acid and atrial fibrillation. Prospective studies (including cohort or nested case-control) that reported the serum uric acid and atrial fibrillation were identified through electronic searches using EMBASE, PubMed, and the Cochrane Library database. The exposure-effect analysis was performed using a stage robust error meta-regression. Eleven studies were included, with a total of 6831 cases of atrial fibrillation among 527 908 individuals. Both the highest (risk ratio (RR), 1.9; 95% confidence interval (CI), 1.64-2.23; I²  = 0%) and intermediate (RR, 1.36; 95% CI, 1.16-1.59; I²  = 36%) level of serum uric acid were associated with increased risks of atrial fibrillation compared to the patients with the lowest level of serum uric acid. In the exposure-effect analysis, for each 1 mg/dL increase in serum uric acid level, the incidence of atrial fibrillation increased by 21% (RR, 1.21; 95% CI, 1.12-1.32; I²  = 78%). Furthermore, a significant positive linear relationship between serum uric acid and the risk of atrial fibrillation, P_nonlinearity  = 0.47 was found. The exposure-effect analysis demonstrated that serum uric acid over 5.0 mg/dL significantly increased the risk of atrial fibrillation. There was a positive linear association between serum uric acid and risk of atrial fibrillation, both in subjects with noruricaemia and hyperuricaemia. More studies are needed to explore the impact of serum uric acid reduction on the incidence of atrial fibrillation.

Cohort Study of Repeated Measurements of Serum Urate and Risk of Incident Atrial Fibrillation

Background Current evidence on the association between serum urate and risk of atrial fibrillation ( AF ) is limited by cross-sectional designs and 1-time measurement of serum urate. The roles of serum urate, gout-related inflammation, and systemic inflammation in the etiology of AF are currently unknown. This gap is important, given that systemic inflammation is a recognized risk factor for AF . Methods and Results We conducted a prospective cohort study of 123 238 Chinese patients from 2006 to 2014. Serum urate concentrations were measured in 2006, 2008, 2010, and 2012. Incident AF cases were identified via biennial 12-lead ECG assessment. We used a Cox proportional hazards model to examine the sex-specific associations of cumulative average serum urate and changes in serum urate accounting for baseline level with risk of incident AF . We also assessed the joint associations of serum urate and high-sensitivity C-reactive protein levels. Comparing extreme categories, participants with the highest quintile of serum urate had 1.91-fold higher risk of AF (adjusted hazard ratio: 1.91; 95% CI, 1.32-2.76; P=0.001 for trend). Participants with both high serum urate and high-sensitivity C-reactive protein had 2.6-fold elevated risk of incident AF compared with those with normal levels of serum urate and high-sensitivity C-reactive protein (adjusted hazard ratio: 2.63; 95% CI, 1.63-4.23). Conclusions High serum urate levels and increases in serum urate over time were associated with increased risk of incident AF . Patients with high levels of both serum urate and high-sensitivity C-reactive protein had substantially higher risk of AF .

Uric acid and the cardio-renal effects of SGLT2 inhibitors

Sodium/glucose co-transporter-2 (SGLT2) inhibitors, which lower blood glucose by increasing renal glucose elimination, have been shown to reduce the risk of adverse cardiovascular (CV) and renal events in type 2 diabetes. This has been ascribed, in part, to haemodynamic changes, body weight reduction and several possible effects on myocardial, endothelial and tubulo-glomerular functions, as well as to reduced glucotoxicity. This review evaluates evidence that an effect of SGLT2 inhibitors to lower uric acid may also contribute to reduced cardio-renal risk. Chronically elevated circulating uric acid concentrations are associated with increased risk of hypertension, CV disease and chronic kidney disease (CKD). The extent to which uric acid contributes to these conditions, either as a cause or an aggravating factor, remains unclear, but interventions that reduce urate production or increase urate excretion in hyperuricaemic patients have consistently improved cardio-renal prognoses. Uric acid concentrations are often elevated in type 2 diabetes, contributing to the "metabolic syndrome" of CV risk. Treating type 2 diabetes with an SGLT2 inhibitor increases uric acid excretion, reduces circulating uric acid and improves parameters of CV and renal function. This raises the possibility that the lowering of uric acid by SGLT2 inhibition may assist in reducing adverse CV events and slowing progression of CKD in type 2 diabetes. SGLT2 inhibition might also be useful in the treatment of gout and gouty arthritis, especially when co-existent with diabetes.

Serum Uric Acid and Atrial Fibrillation: Meta-analysis

Hyperuricemia has been recently speculated to be associated with the development of atrial fibrillation (AF). A meta-analysis of observational studies was conducted to explore the relationship between serum uric acid (SUA) and AF. We searched the MEDLINE, EMBASE, and CINAHL databases and performed extensive bibliography search to identify studies with mean SUA level for patients with and without AF. Key search terms were "atrial fibrillation" and "uric acid." Under the random-effects model, the pooled standardized difference in means between patients with and without AF was calculated. A total of 24 studies with 30,609 patients were included for quantitative analyzation of the difference in SUA levels between the patients with and without AF. The SUA level of patients with atrial AF was found to be significantly higher compared with those without AF (standardized difference in means = 0.66; 95% confidence interval, 0.43-0.88; P < 0.0001). The mean SUA level of patients with AF significantly is higher than those without AF.

Effects of Uric Acid on Diabetes Mellitus and Its Chronic Complications

With the deepening of the researches on uric acid, especially in the study of metabolic diseases, uric acid has been found to be closely related to obesity, metabolic syndrome, nonalcoholic fatty liver disease, diabetes, and other metabolic diseases. Uric acid causes a series of pathophysiological changes through inflammation, oxidative stress, vascular endothelial injury, and so on and thus subsequently promotes the occurrence and development of diseases. This review confirmed the positive correlation between uric acid and diabetes mellitus and its chronic complications through the pathogenesis and clinical studies aspects.

Epidemiological Characteristics of Atrial Fibrillation in Southern China: Results from the Guangzhou Heart Study

Precise prevalence of atrial fibrillation (AF) and the associated risk factors in southern China are rarely reported. This large population-based follow-up study, the Guangzhou Heart Study, was conducted from 2015 to 2017 to fill up this gap. Permanent residents aged 35 years and above in Guangzhou city were enrolled and demographic factors of participants were collected by a structured questionnaire. Examinations of physical, electrocardiographic and biochemical indicators were performed following a standard operation procedure designed prior to the field investigation. Descriptive statistics were used to evaluate basic characteristics of the study participants, and multivariate logistic regression model was performed to assess the AF prevalence-related factors. The detailed study design, the baseline characteristics and the prevalence of AF were reported here. In total, 12,013 residents were enrolled, and the percentage of participants from rural and urban areas was 53.92% and 46.08%, respectively. In total, 90.57% participants aged 40-79 years old and the proportion of women was more than men (64.98% vs. 35.02%). Overall, the prevalence of AF among the participants was 1.46%. Increasing age, male sex and widowed marital status were associated with higher AF prevalence (P-value < 0.05). The prevalence of AF increased with age and climbed to approximately 5% in residents aged 80 years and over. Residents with abnormal higher blood level of total cholesterol tended to have a lower AF prevalence but a higher prevalence of AF was observed in female participants with lower level of high density lipoprotein cholesterol land higher level uric acid (all P-value < 0.05). Personal illness such as hypertension, diabetes mellitus, dyslipidemia, myocardial infarction, heart failure, stroke and transient ischemic were significantly linked to the attack of AF (all P-value < 0.05). This study will be rich resource for investigating environmental exposure and individual genetic diathesis of AF and other common cardiovascular diseases in Chinese population.

Neocucurbitacin D, a novel lactone-type norcucurbitacin as xanthine oxidase inhibitor from Herpetospermum pedunculosum

A novel lactone-type norcucurbitacin, designated as neocucurbitacin D (1), together with five known cucurbitane triterpenes were isolated from traditional Tibetan medicine "Se Ji Mei Duo", which is the seed of Herpetospermum pedunculosum (Ser.) C.B. Clarke. The structure of neocucurbitacin D was elucidated by spectroscopic analysis, including 2D NMR and X-ray techniques. Compounds 1-6 were screened for their xanthine oxidase (XOD) inhibitory activity. Compound 1, 2 and 4 exhibited significant XOD inhibition with IC₅₀ values ranging from 10.16 to 18.41 μM. The absolute stereochemistry and XOD inhibitiory activity of lactone-type norcucurbitacins was reported firstly.

Alterations of the Gut Microbiome Associated With the Treatment of Hyperuricaemia in Male Rats

Hyperuricaemia is an important risk factor for many diseases including gout, hypertension, and type II diabetes. The gut microbiota is associated with hyperuricaemia and has also been demonstrated to play significant roles in the effects of drug therapy. This study used Illumina MiSeq sequencing to explore alterations of the gut microbiome associated with allopurinol and benzbromarone treatment in the male rat with hyperuricaemia. After drug treatment, both allopurinol and benzbromarone caused an increase of the genera Bifidobacterium and Collinsella and a decrease of the genera Adlercreutzia and Anaerostipes. In addition, allopurinol and benzbromarone caused respective unique changes in genera. The genera Bilophila, Morganella, and Desulfovibrio specifically decreased due to allopurinol treatment. Decreased Butyricimonas and Ruminococcus and increased Proteus were caused by benzbromarone treatment. The PICRUST analysis indicated that allopurinol renovated the disorder of nucleotide metabolism and benzbromarone renovated the disorder of lipid metabolism in the gut microbiota of male rats with hyperuricaemia. These findings demonstrated that the gut microbiota may be altered by the treatment of hyperuricaemia with allopurinol and benzbromarone in male rats. Such alterations of the gut microbiota could be considered as indicators of the effectiveness of drug therapy.

Gout and arrhythmias: In search for causation beyond association

Gout is a systemic disease, characterized by the formation and deposition of crystals in tissues (mainly in and around the joints) of individuals with elevated serum uric acid levels. Lately, a considerable number of reports relating elevated uric acid and/or gout with rhythm disorders, such as atrial fibrillation, have been published. This review summarizes evidence linking common arrhythmias and hyperuricemia/gout and discusses questions or controversies that surround it. Overall, existing evidence may not be overwhelming, but strongly suggests a positive correlation between uric acid levels and common rhythm disorders. Needless to say that such a link - as a univariate association between the two - is to be expected, given the extensive overlap of risk factors and comorbidities of hyperuricemia/gout and arrhythmias. However, the observed associations seem to persist - in most studies - after extensive adjustment for potential confounders. Still, multivariable analyses of epidemiologically collected data cannot substitute for proof coming from basic and clinical studies. There is obviously a need for further basic research to establish a causal relationship between uric acid effects and arrhythmias, as well as translational studies and clinical trials to investigate the therapeutic implications of such a relationship. Simply put, we are fairly certain that there is association, but proof of causation is what we are still in want of.

Levels of serum uric acid at admission for hypoglycaemia predict 1-year mortality

AIMS

Hypoglycaemia represents a critical burden with clinical and social consequences in the management of diabetes. Serum uric acid (SUA) has been associated with cardiovascular diseases (CVD), but no conclusive findings are available nowadays in patients suffering from hypoglycaemia. We investigated whether SUA levels at the time of hypoglycaemia could predict all-cause mortality after 1-year follow-up.

METHODS

In total, 219 patients admitted to the Emergency Department (ED) of Ospedale Policlinico S. Martino of Genoa (Italy) have been enrolled between January 2011 and December 2014. The primary endpoint of the study consisted in determining whether SUA levels at the time of ED admission could predict the occurrence of death after 1 year.

RESULTS

The majority of patients were diabetic, especially type 2. CVD and chronic kidney disease were prevalent comorbidities. By a cut-off value obtained by the receiver operating characteristic curve analysis, a Kaplan-Meier analysis demonstrated that patients with SUA levels > 5.43 mg/dL were more prone to death after 1 year compared to those with lower SUA levels. The risk of death increased with high SUA levels both in the univariate and the multivariate models including estimated glomerular filtration rate, C-reactive protein, type of diabetes, and age-adjusted Charlson comorbidity index.

CONCLUSIONS

SUA could be useful as a predictor of 1-year mortality in hypoglycaemic patients, irrespective of severe comorbidities notably increasing the risk of death in these frail patients.

Hyperuricemia is associated with an increased prevalence of paroxysmal atrial fibrillation in patients with type 2 diabetes referred for clinically indicated 24-h Holter monitoring

PURPOSE

Several studies have reported an association between hyperuricemia and increased risk of permanent atrial fibrillation (AF) in patients with and without type 2 diabetes mellitus (T2DM). Currently, no published data are available on the relationship between hyperuricemia and risk of paroxysmal AF.

METHODS

We retrospectively evaluated 245 T2DM outpatients without pre-existing AF, cancer, cirrhosis and end-stage renal disease, who underwent a 24-h ECG-Holter monitoring for various clinical indications. Hyperuricemia was defined as a serum uric acid level >7 mg/dl for men and >6 mg/dl for women or allopurinol use. The diagnosis of paroxysmal AF was confirmed in affected individuals on the basis of 24-h ECG-Holter monitoring by experienced cardiologists.

RESULTS

Hyperuricemia was observed in 59 (24.1%) patients, whereas paroxysmal AF was found in 11 (4.5%) patients. The prevalence of paroxysmal AF was higher in patients with hyperuricemia than in those without hyperuricemia (10.2 vs. 2.7%, p = 0.026). Logistic regression analysis showed that hyperuricemia was associated with an increased risk of prevalent paroxysmal AF. This association remained significant even after adjustment for age, metabolic syndrome and chronic kidney disease (adjusted-odds ratio 4.01, 95% CI 1.08-14.9; p = 0.039). Similar results were found when we used serum uric acid levels as a continuous measure.

CONCLUSIONS

This study shows for the first time that hyperuricemia is independently associated with an approximately fourfold increased risk of prevalent paroxysmal AF in patients with T2DM. These findings may partly explain the increased risk of permanent atrial fibrillation and cardiovascular death observed among patients with hyperuricemia.

Relation of elevated serum uric acid levels to first-degree heart block and other cardiac conduction defects in hospitalized patients with type 2 diabetes

AIMS

Several studies have reported that moderately elevated serum uric acid levels are associated with an increased risk of tachyarrhythmias (mainly atrial fibrillation) in patients with and without type 2 diabetes mellitus (T2DM). It is currently unknown whether an association also exists between elevated serum uric acid levels and cardiac conduction defects in patients with T2DM.

METHODS

We retrospectively analyzed a hospital-based sample of 967 patients with T2DM discharged from our Division of Endocrinology over the years 2007-2014. Standard electrocardiograms were performed on all patients and were interpreted by expert cardiologists.

RESULTS

Overall, 267 (27.6%) patients had some type of conduction defects on electrocardiograms (defined as at least one block among first-degree atrio-ventricular block, second-degree block, third-degree block, left bundle branch block, right bundle branch block, left anterior hemi-block or left posterior hemi-block). Patients in the 3rd serum uric acid tertile had a higher prevalence of any cardiac conduction defects than those belonging to 2nd or 1st tertile, respectively (35.8% vs. 25.0% vs. 22.6%; p<0.0001). Elevated serum uric acid levels were associated with a nearly twofold increased risk of cardiac conduction defects after adjustment for age, sex, hemoglobin A1c, diabetes duration, metabolic syndrome, chronic kidney disease, chronic obstructive pulmonary disease, ischemic heart disease, valvular heart disease and medication use (adjusted-odds ratio 1.84, 95% confidence intervals 1.2-2.9; p=0.009).

CONCLUSIONS

Moderately elevated serum uric acid levels are associated with an increased prevalence of any cardiac conduction defects in hospitalized patients with T2DM, independent of multiple risk factors and potential confounding variables.

An association of smoking with serum urate and gout: A health paradox

BACKGROUND

The potential effect of cigarette smoking on levels of serum urate and risk of gout has been considered by a large number of studies, either as the primary variable of interest or as a covariate.

METHODS

Here we systematically review the published evidence relating to the relationship of smoking with serum urate, hyperuricaemia, and gout.

RESULTS

Many studies have reported that smoking reduces serum urate, however, the evidence has not been conclusive with other studies pointing to the opposite or no effect. It has also been suggested that smoking reduces the risk of gout, although there is some evidence to contradict this finding.

CONCLUSION

A consensus has yet to be reached as to the effect of smoking on serum urate levels and the risk of gout.

Serum uric acid and atrial fibrillation

BACKGROUND

Atrial fibrillation (AF) represents a significant health concern, due to the increased prevalence, morbidity, and mortality.

METHODS AND RESULTS

There is a growing body of evidence correlating serum uric acid (SUA) with cardiovascular diseases such as arterial hypertension and AF.

CONCLUSION

Thus, a question arises as to whether SUA levels have a role in the pathophysiology of AF development.

Uric acid in the pathogenesis of metabolic, renal, and cardiovascular diseases: A review

The association between uric acid (UA) on one side and systemic hypertension (Htn), dyslipidemia, glucose intolerance, overweight, fatty liver, renal disease and cardiovascular disease (CVD) on the other side is well recognized. However, the causal relationship between UA and these different clinical problems is still debatable. The recent years have witnessed hundreds of experimental and clinical trials that favored the opinion that UA is a probable player in the pathogenesis of these disease entities. These studies disclosed the strong association between hyperuricemia and metabolic syndrome (MS), obesity, Htn, type 2 diabetes mellitus (DM), non-alcoholic fatty liver disease, hypertriglyceridemia, acute kidney injury, chronic kidney disease (CKD), coronary heart disease (CHD), heart failure and increased mortality among cardiac and CKD patients. The association between UA and nephrolithiasis or preeclampsia is a non-debatable association. Recent experimental trials have disclosed different changes in enzyme activities induced by UA. Nitric oxide (NO) synthase, adenosine monophosphate kinase (AMPK), adenosine monophosphate dehydrogenase (AMPD), and nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase are affected by UA. These changes in enzymatic activities can lead to the observed biochemical and pathological changes associated with UA. The recent experimental, clinical, interventional, and epidemiologic trials favor the concept of a causative role of UA in the pathogenesis of MS, renal, and CVDs.