Unraveling the relationship between serum uric acid levels and cardiovascular risk

Relationship between serum uric acid levels and uric acid lowering therapy with the prognosis of patients with heart failure with preserved ejection fraction: a meta-analysis

Aims

This meta-analysis aimed to explore the association between serum uric acid levels and the efficacy of uric acid-lowering therapies on clinical outcomes among patients with heart failure with preserved ejection fraction (HFpEF).

Methods

A comprehensive literature search was conducted through October 21, 2023, across PubMed, Embase, Cochrane Library, and Web of Science databases. The pooled effect sizes were estimated and presented with their respective 95% confidence intervals (CI). Subgroup analyses were conducted based on various factors, including sample size (<1,000 vs. ≥1,000), follow-up duration (<2 years vs. ≥2 years), study quality (assessed by a score of <7 vs. ≥7), ethnicity (Non-Asian vs. Asian), study design (prospective vs. retrospective), type of heart failure (HF) (acute vs. chronic), presence of hyperuricemia (yes or no), left ventricular ejection fraction (LVEF) thresholds (≥45% vs. ≥50%), and the type of uric acid-lowering therapy (traditional vs. novel).

Results

The analysis included a total of 12 studies. Elevated serum uric acid levels were significantly linked to an increased risk of all-cause mortality [relative risk (RR): 1.21, 95% CI: 1.06-1.37, P = 0.004] and cardiovascular (CV) mortality (RR: 1.71, 95% CI: 1.42-2.04, P < 0.001) in HFpEF patients. Subgroup analyses confirmed this association, particularly in non-Asian populations, those with chronic HFpEF, and studies with a follow-up duration of two years or more. Additionally, higher uric acid levels were associated with an increased risk of HF-related hospitalization [hazard ratio (HR): 1.61, 95% CI: 1.12-2.34, P = 0.011]. Regarding treatment, uric acid-lowering therapy did not show a significant effect on reducing mortality in HFpEF patients. However, it was associated with a decreased risk of hospitalization due to HF (RR: 0.85, 95% CI: 0.79-0.91, P < 0.001).

Conclusion

The findings of this study highlight the prognostic significance of serum uric acid levels in HFpEF and suggest that uric acid-lowering therapy may be beneficial in reducing the incidence of HF hospitalizations. Further research is warranted to elucidate the mechanisms by which uric acid-lowering therapy confers its potential benefits.

A methodological study of exposome based on an open database: Association analysis between exposure to metal mixtures and hyperuricemia

BACKGROUND

Exposome recognizes that humans are constantly exposed to multiple environmental factors, and elucidating the health effects of complex exposure mixtures places greater demands on analytical methods.

OBJECTS

We aimed to explore the association between mixed exposure to metals and hyperuricemia (HUA), and highlight the potential of explainable machine learning (EML) and causal mediation analysis (CMA) for application in the analysis of exposome data.

METHODS

Pre-pandemic data from the National Health and Nutrition Examination Survey (NHANES) 2011-2020 and a total of 13780 individuals were included. We first used traditional statistical models (multiple logistic regression (MLR) and restricted cubic spline regression (RCS)) and EML to explore associations between mixed metals exposures and HUA, followed by the CMA using the 4-way decomposition method to analyze the interaction and mediation effects among BMI or estimated glomerular filtration rate (eGFR), metals and HUA.

RESULTS

The prevalence of HUA was 18.91% (2606/13780). The MLR showed that mercury (Q4 vs Q1: OR = 1.08, 95% CI:1.02-1.14) and lead (Q4 vs Q1: OR = 1.23, 95% CI:1.13-1.34) were generally positively associated with HUA. Higher concentrations of lead, mercury, selenium and manganese were associated with the increased odds of HUA, and BMI and eGFR were the top two variables attributable to the risk of developing HUA in the EML. Subgroup analyses from the MLR and EML consistently demonstrated the positive relationship between exposure to lead, mercury and selenium in participants with BMI <25 kg/m2 and BMI ≥30 kg/m2. BMI mediated 32.12% of the association between lead exposure and HUA, and the interaction between BMI and lead accounted for 3.88% of the association in the CMA.

CONCLUSIONS

Heavy metals can increase the HUA risk and BMI or eGFR can mediate and interact with metals to cause HUA. Future studies based on exposome can attempt to utilize the EML and CMA.

Inflammatory pathways in heart failure with preserved left ventricular ejection fraction: implications for future interventions

Many patients with symptoms and signs of heart failure have a left ventricular ejection fraction ≥50%, termed heart failure with preserved ejection fraction (HFpEF). HFpEF is a heterogeneous syndrome mainly affecting older people who have many other cardiac and non-cardiac conditions that often cast doubt on the origin of symptoms, such as breathlessness, or signs, such as peripheral oedema, rendering them neither sensitive nor specific to the diagnosis of HFpEF. Currently, management of HFpEF is mainly directed at controlling symptoms and treating comorbid conditions such as hypertension, atrial fibrillation, anaemia, and coronary artery disease. HFpEF is also characterized by a persistent increase in inflammatory biomarkers. Inflammation may be a key driver of the development and progression of HFpEF and many of its associated comorbidities. Detailed characterization of specific inflammatory pathways may provide insights into the pathophysiology of HFpEF and guide its future management. There is growing interest in novel therapies specifically designed to target deregulated inflammation in many therapeutic areas, including cardiovascular disease. However, large-scale clinical trials investigating the effectiveness of anti-inflammatory treatments in HFpEF are still lacking. In this manuscript, we review the role of inflammation in HFpEF and the possible implications for future trials.

The effect of SGLT-2i administration on red blood cell distribution width in patients with heart failure and type 2 diabetes mellitus: A randomized study

Background

Recent studies suggest that the pivotal mechanism of sodium glucose co-transporter-2 inhibitors (SGLT-2i) favorable action in patients with heart failure (HF) and type 2 diabetes mellitus (DM) is the stimulation of erythropoiesis via an early increase in erythropoietin (EPO) production which leads to hematocrit rise. Red blood cell distribution width (RDW) is a simple hematological parameter which reflects the heterogeneity of the red blood cell size (anisocytosis). Since, EPO has been also implicated in the pathophysiology of RDW increase, the current mechanistic study examined the effect of SGLT-2i administration on red blood cells size (RDW) in patients with HF and DM.

Methods

The present was a prospective single-center study. Patients (N=110) were randomly assigned to dapagliflozin (10 mg a day on top of antidiabetic treatment) or the control group. Inclusion criteria were: (a) age > 18 years, (b) history of type 2 DM and hospitalization for HF exacerbation within 6 months. The evaluation of patients (at baseline, 6 and 12 months) included clinical assessment, laboratory blood tests, and echocardiography. Data were modeled using mixed linear models with dependent variable the RDW index. In order to find factors independently associated with prognosis (1-year death or HF rehospitalization), multiple logistic regression was conducted with death or HF rehospitalization as dependent variable.

Results

An RDW increase both after 6 and after 12 months was observed in the SGLT-2i (dapagliflozin) group (p < 0.001 for all time comparisons), whereas RDW didn't change significantly in the control group. The increase in RDW was positively correlated with EPO, while negatively correlated with ferritin and folic acid (p < 0.005 for all). Baseline RDW was significantly associated with 1-year death or rehospitalization, after adjusting for group (SGLT-2i vs. control), age, gender, smoking and BMI at baseline.

Conclusion

RDW increased with time in patients with HF and DM who received SGLT-2i (dapagliflozin). The increased RDW rates in these patients may stem from the induction of hemopoiesis from dapagliflozin. Baseline RDW was found to be independently associated with outcome in patients with HF and DM.

Sex difference in heart failure risk associated with febuxostat and allopurinol in gout patients

Background

Gout or rapid reduction in serum uric acid level may increase the incidence of heart failure (HF). To compare the risk of HF between febuxostat and allopurinol in gout patients with coexisting cardiovascular (CV) diseases, the varying severity would be likely to confound the risk estimation. Gout and HF are both sex-related diseases, and the risk difference from the urate-lowering agents between women and men remains unknown.

Aims

To evaluate the HF hospitalisations risk of febuxostat and allopurinol in gout patients in real-world settings.

Methods

A population-based cohort enrolled patients with allopurinol or febuxostat initiation from 2011 to 2018. Participants were grouped into, without (low CV risk group) or with (high CV risk group) a history of recent major CV admission. The primary outcome was HF hospitalization. The secondary outcomes were composite CV events, all-cause mortality, and the cause of CV mortality. We used the ‘as-treated' analysis and Cox proportional hazards model after propensity score (PS) matching. Patients were further stratified into men and women to evaluate the gender differences.

Results

Febuxostat users had a significantly higher risk of HF hospitalization than allopurinol users in gout patients either with low CV risk [hazard ratio (HR) 1.39; 95% confidence interval (CI) 1.25–1.55] or high CV risk [HR 1.36; 95% CI 1.22–1.52]. Particularly, women with gout had a higher risk of HF hospitalization than men.

Conclusion

The HF hospitalization risk was highest in gout women with high CV risk and febuxostat use. Monitoring of HF is warranted in these patients.

Combined exposure to multiple metals on serum uric acid in NHANES under three statistical models

BACKGROUND

There are rare researches on the correlations between metals exposure and serum uric acid (SUA), and existing research has only investigated the single metal effect. This study aimed to investigate the combined effects of metal mixtures on SUA and hyperuricemia using three statistical models.

METHODS

In this study, the data were extracted from three cycle years of the National Health and Nutrition Examination Survey (NHANES). Subsequently, generalized linear regression, weighted quantile regression (WQS) and Bayesian kernel machine regression (BKMR) models were fitted to evaluate the correlations between metal mixtures and both SUA and hyperuricemia.

RESULTS

Of 3926 participants included, 19.13% participants had hyperuricemia. It was found using multi-metals generalized linear regression models that there were positive correlations of arsenic and cadmium with both outcomes. The negative correlations were identified in cobalt, iodine, and manganese with SUA concentration, whereas only cobalt was negatively correlated with hyperuricemia. Based on the WQS regression model fitted in positive direction, it was suggested that the WQS indices were significantly correlated with SUA (β = 6.64, 95% CI: 3.14-10.13) and hyperuricemia (OR = 1.25, 95% CI: 1.08-1.44); however, the result achieved by using the model fitted in negative direction indicated that the WQS indices were only significantly correlated with SUA (β = -5.29, 95%CI: 8.02 ∼ -2.56). With the use of the BKMR model, a significant increasing trend between metal mixtures and hyperuricemia was found, while no significant overall effect of metal mixtures on SUA was identified. The predominant roles of arsenic, cadmium, and cobalt in the change of SUA and hyperuricemia risk were found using all three models.

CONCLUSION

The finding of this study revealed that metal mixtures might have a positive combined effect on hyperuricemia. The mutual verification of two outcomes using the three different models provided strong public health implications for protecting people from heavy metal pollution and preventing hyperuricemia.

U-Shaped Association Between Serum Uric Acid Level and Hypertensive Heart Failure: A Genetic Matching Case-Control Study

Background: Heart failure (HF) is a global pandemic and lays an added burden on public healthcare. Previous studies indicated that high and low serum uric acid levels are associated with worse outcomes in many diseases. Reduced serum uric acid may not result in a better outcome.

Methods: A comparative, matched cross-sectional study design was implemented. The matching variables were age, sex, BMI, BP, and histories of CKD, CVD, diabetes mellitus, stroke, hyperlipidemia. We reviewed the electronic medical records to identify patients diagnosed with hypertension or hypertensive heart failure (HHF) admitted to Beijing Hospital's cardiology department.

Results: The median age of the two groups after matching are 71. There are 55.6% males in the hypertension group and 53.8% in the heart failure group. Univariate logistic regression analysis showed that UA's quadratic term is significant (OR = 1.00, 95% CI 1.00 to 1.00; P = 0.03), which indicated a u-shaped relationship between hypertension and HHF. FBS (OR = 0.22, 95% CI 0.05 to 0.95, p = 0.07) and HDL (OR = 1.23, 95% CI 1.00 to 1.54, P = 0.05) were not significant but close.

Conclusion: Our results supported that both low and high uric acid levels were predictive of hypertensive heart failure. Besides, high-density lipoprotein cholesterol and fasting blood sugar were also associated with hypertensive heart failure. Low-density lipoprotein cholesterol was not associated with hypertensive heart failure.

Serum uric acid and outcomes in patients with chronic heart failure through the whole spectrum of ejection fraction phenotypes: Analysis of the ESC-EORP Heart Failure Long-Term (HF LT) Registry

BACKGROUND

Retrospective analyses of clinical trials indicate that elevated serum uric acid (sUA) predicts poor outcome in heart failure (HF). Uric acid can contribute to inflammation and microvascular dysfunction, which may differently affect different left ventricular ejection fraction (LVEF) phenotypes. However, role of sUA across LVEF phenotypes is unknown.

OBJECTIVES

We investigated sUA association with outcome in a prospective cohort of HF patients stratified according to LVEF.

METHODS

Through the Heart Failure Long-Term Registry of the European Society of Cardiology (ESC-EORP-HF-LT), 4,438 outpatients were identified and classified into: reduced (<40% HFrEF), mid-range (40-49% HFmrEF), and preserved (≥50% HFpEF) LVEF. Endpoints were the composite of cardiovascular death/HF hospitalization, and individual components.

RESULTS

Median sUA was 6.72 (IQ:5.48-8.20) mg/dl in HFrEF, 6.41 (5.02-7.77) in HFmrEF, and 6.30 (5.20-7.70) in HFpEF. At a median 372-day follow-up, the composite endpoint occurred in 648 (13.1%) patients, with 176 (3.6%) deaths and 538 (10.9%) HF hospitalizations. Compared with lowest sUA quartile (Q), Q-III and Q-IV were significantly associated with the composite endpoint (adjusted HR 1.68: 95% CI 1.11-2.54; 2.46: 95% CI 1.66-3.64, respectively). By univariable analyses, HFrEF and HFmrEF patients in Q-III and Q-IV, and HFpEF patients in Q-IV, showed increased risk for the composite endpoint (P<0.05 for all); after model-adjustment, significant association of sUA with outcome persisted among HFrEF in Q-IV, and HFpEF in Q-III-IV.

CONCLUSIONS

In a large, contemporary-treated cohort of HF outpatients, sUA is an independent prognosticator of adverse outcome, which can be appreciated in HErEF and HFpEF patients.

Human concentrations of uric acid scavenges adaptive and maladaptive reactive oxygen species in isolated rat hearts subjected to ischemic stress

Uric acid is a purine degradation product but also an important antioxidant and reactive oxygen species (ROS) scavenger. Experimental settings that mimic myocardial ischemia-reperfusion have not included uric acid despite that it is always present in human extracellular fluid and plasma. We hypothesized that uric acid has an important role in myocardial ROS scavenging. Here, we tested the cardiac response to uric acid on infarct size following ischemia-reperfusion with and without exacerbated oxidative stress due to acute pressure overload and during preconditioning. We also examined mitochondrial respiration and ROS-induced mitochondrial permeability transition pore opening. Under exacerbated ROS stress induced by high-pressure perfusion, uric acid lowered oxidative stress and reduced infarct size. In contrast, uric acid blocked cardioprotection induced by ischemic preconditioning. However, this effect was reversed by probenecid, an inhibitor of cellular uptake of uric acid. In accordance, in intact cardiomyocytes, extracellular uric acid reduced the susceptibility of mitochondria towards opening of the permeability transition pore, suggesting that uric acid may prevent ischemia-reperfusion injury due to scavenging of maladaptive ROS. Moreover, as uric acid also scavenges adaptive ROS, this may interfere with preconditioning. Altogether, uric acid might be a confounder when translating preclinical experimental results into clinical treatment.