Serum uric acid is associated with coronary artery calcification

Serum Uric Acid Levels and Subclinical Atherosclerosis: Results From the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

High serum uric acid (sUA) has been associated with coronary artery calcium (CAC) and increased carotid intima-media thickness (cIMT) in people at high cardiovascular risk. However, association is unclear in apparently healthy individuals. Our study aims to evaluate association between sUA and subclinical atherosclerosis measures: CAC and increased cIMT, in apparently healthy adults enrolled in ELSA-Brasil. A total of 4096 participants without previous coronary artery disease, stroke, and use of urate-lowering drugs, underwent CAC and cIMT assessment. All analyses were stratified by sex. Serum uric acid categorized by quintiles was the exposure variable. Thorough cardiovascular risk factor evaluation was performed, and association between sUA quintiles and CAC and cIMT was analyzed by linear regression using ln(CAC + 1) and cIMT, both as continuous variables. Median age of the sample was 49.0 (44.0-56.0) years (women: 55.1%; 59.1% were white). Mean values of sUA were 6.5 ± 1.4 mg/dL for men, and 4.9 ± 1.2 mg/dL for women. The highest quintile (Q5) of sUA was independently associated with cIMT in women (beta-coefficient: 0.022; 95% CI: 0.007-0.036; P = 0.003) and men (beta-coefficient: 0.020; 95% CI: 0.002-0.038; P = 0.032). Regarding CAC, no association was found: men's Q5 (beta-coefficient: -0.142; 95% CI: -0.436 to 0.153; P = 0.347) and women's Q5 (beta-coefficient: 0.046; 95% CI: -0.152 to 0.245; P = 0.647). In this cohort, the highest sUA quintiles were independently associated with cIMT in both women and men. No association was found between sUA and the presence of CAC.

Serum uric acid is associated with coronary artery calcification in early chronic kidney disease: a cross-sectional study

Background

Although uric acid (UA) is regarded as a risk factor for cardiovascular disease, whether UA is an independent risk factor contributing to coronary artery calcification in chronic kidney disease (CKD) is not well known. We evaluated whether UA level is associated with coronary artery calcium (CAC) score in a predialysis CKD cohort.

Methods

A total of 1,350 subjects who underwent coronary computed tomography as part of the KoreaN Cohort Study for Outcome in Patients With Chronic Kidney Disease were analysed. We conducted a logistic regression analysis to evaluate the association between UA and the presence of CAC.

Results

CAC was detected in 705 (52.2 %) patients, and the level of UA was significantly higher in CAC > 0 patients. UA showed a positive relationship with CAC > 0 in age- and sex-adjusted logistic regression analysis (Odds ratio (OR) 1.11, 95 % confidence interval (CI) 1.04–1.19, P = 0.003). However, UA showed no association with CAC > 0 in multivariate analysis. Further analysis showed that UA showed a positive association with CAC > 0 only in estimated glomerual filtration rate (eGFR) > 60 ml/min/1.73 m² (OR 1.23, 95 % CI 1.02–1.49, P = 0.036) but not in eGFR 30–59 ml/min/1.73 m² (OR 0.92, 95 % CI 0.78–1.08, P = 0.309) or < 30 ml/min/1.73 m² (OR 0.92, 95 % CI 0.79–1.08, P = 0.426).

Conclusions

UA level was significantly associated with CAC in early CKD, but not in advanced CKD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-021-02463-2.

Circulating levels of fetuin-A are associated with moderate-severe hepatic steatosis in young adults

PURPOSE

The hepatokine fetuin-A might have a role as molecular link between non-alcoholic fatty liver disease (NAFLD) and type 2 diabetes mellitus (T2DM). The aim of this study was to evaluate the association between fetuin-A and the prevalence and severity of NAFLD in a population of young adults.

METHODS

Ninety-seven adults (age 35.7 ± 12.4 years, female 64.9%), enrolled in a previous study evaluating NAFLD prevalence in the presence or absence of family history of T2DM, were included. Serum levels of fetuin-A (ELISA BioVendor, Czech Republic) and the main biochemical parameters were assessed. Presence and severity of NAFLD were evaluated by ultrasonography (Toshiba, Japan). A linear regression was run to predict fetuin-A levels and a logistic regression was performed to predict moderate-severe steatosis.

RESULTS

Fetuin-A associated inversely with age (ß - 0.12, p = 0.03) and directly with body mass index (BMI) (ß 0.5, p = 0.048), waist circumference (WC) (ß 0.3, p = 0.027), triglycerides (TG) (ß 0.1, p = 0.001) and uric acid (ß 1.7, p = 0.018), after adjustment for age and sex. In a model including age, BMI, WC, TG and uric acid, age (ß - 0.2, p = 0.002) and TG (ß 0.04, p = 0.02) were independent predictors of fetuin-A. Prevalence of steatosis was 66%. The rates of mild and moderate-severe steatosis were 50.5% and 15.5%, respectively. In the logistic model, the independent predictors of moderate-severe steatosis were fetuin-A (OR 1.22, p = 0.036), age (OR 1.17, p = 0.01) and BMI (OR 2.75, p = 0.011).

CONCLUSION

In a sample of young adults, circulating levels of fetuin-A correlated with moderate-severe NAFLD, independent of confounders, and with some metabolic parameters. Fetuin-A might be a useful marker to predict NAFLD and metabolic disorders.

Uremic Toxins and Vascular Calcification-Missing the Forest for All the Trees

The cardiorenal syndrome relates to the detrimental interplay between the vascular system and the kidney. The uremic milieu induced by reduced kidney function alters the phenotype of vascular smooth muscle cells (VSMC) and promotes vascular calcification, a condition which is strongly linked to cardiovascular morbidity and mortality. Biological mechanisms involved include generation of reactive oxygen species, inflammation and accelerated senescence. A better understanding of the vasotoxic effects of uremic retention molecules may reveal novel avenues to reduce vascular calcification in CKD. The present review aims to present a state of the art on the role of uremic toxins in pathogenesis of vascular calcification. Evidence, so far, is fragmentary and limited with only a few uremic toxins being investigated, often by a single group of investigators. Experimental heterogeneity furthermore hampers comparison. There is a clear need for a concerted action harmonizing and standardizing experimental protocols and combining efforts of basic and clinical researchers to solve the complex puzzle of uremic vascular calcification.

Association between serum level of urate and subclinical atherosclerosis: results from the SCAPIS Pilot

BACKGROUND

Hyperuricemia is closely associated with cardiovascular disease (CVD). However, it has not been definitively established whether this association is independent of traditional cardiovascular risk factors (CVRFs) and whether it is gender-dependent. The aim of this study was to investigate in a population-based cohort (age range, 50-64 years) stratified by sex the association between the serum urate (SU) concentration and subclinical atherosclerosis, as reflected in the coronary artery calcification (CAC) score, common carotid intima-media thickness (CIMT), and carotid plaque score.

METHODS

The study involved participants in the Swedish CArdioPulmonary bioImage Study (SCAPIS) Pilot cohort (N = 1040; 48.8% males). This pilot cohort is part of the large population-based SCAPIS with 30,000 participants in the age range of 50-64 years, aimed at improving risk prediction for CVD. Subjects with a self-reported previous history of CVD (N = 68) or gout (N = 3) were excluded. The CAC score was assessed with the Agatston method using computed tomography. CIMT and carotid plaques were quantified by ultrasound. The associations between the SU quartiles and different levels of CAC, CIMT, and carotid plaques were assessed by multivariable logistic regression.

RESULTS

Age, BMI, education level, smoking, physical activity, hs-CRP, hypertension, and dyslipidemia showed no differences between males and females, while CAC (score > 0) and diabetes were both twice as common in men than in women (58% vs 26% and 8% vs 4%, respectively). Higher SU quartiles were in both sexes associated with BMI, hs-CRP, and the prevalence of hypertension, and in women, they were also associated with the prevalence of dyslipidemia. The three upper quartiles of SU (>308μmol/L) were linked to higher CAC scores in men, when adjusting for CVRFs, but not in women. CIMT and carotid plaques showed no correlation to SU in either sex.

CONCLUSIONS

Higher levels of SU are associated with the presence of CAC in men but not in women, whereas SU is not associated with CIMT or carotid plaques in either men or women. This implies that the biological effects of SU differ in men and women or that SU has varying effects on different vascular beds or during the different stages of the atherosclerotic process.

The association between hyperuricemia and coronary artery calcification development: A systematic review and meta-analysis

Hyperuricemia coincides with coronary artery calcification (CAC) development, but the role of serum uric acid (SUA) as a risk factor for CAC remains unclear. The objective of this study was to gain an insight into the association between SUA and CAC in adults by performing a meta-analysis. MEDLINE, EMBASE, the Cochrane Library, and EBSCO (CINAHL) were searched for relevant observational studies published until 2 June 2019. Studies were included only if they reported data on CAC presence (Agatston score > 0) or progression related to hyperuricemia in subclinical adult patients. The pooled estimates of crude and adjusted odds ratios (ORs) and 95% confidence interval (CI) were calculated to evaluate the association between CAC presence or progression and hyperuricemia. A total of 11 studies were identified involving 11 108 adults. The pooled OR based on the frequency of CAC presence showed that patients in the high SUA group had 1.806-fold risk for developing CAC (95% CI: 1.491-2.186) under the minimal threshold of hyperuricemia (more than 6 mg/dL or 357 μmoL/L). When SUA levels were analyzed as categorical variables, the pooled estimate of adjusted ORs was 1.48 (95% CI: 1.23-1.79) for CAC presence. Additionally, for each increase of 1 mg/dL of SUA level, the risk of CAC progression was increased by 31% (95% CI: 1.15-1.49) with an average follow-up duration ranged from 4.6 to 6.1 years. Hyperuricemia is closely associated with increased risk of CAC development and CAC progression in asymptomatic patients.

New Insights into the Roles of Monocytes/Macrophages in Cardiovascular Calcification Associated with Chronic Kidney Disease

Cardiovascular disease (CVD) is an important cause of death in patients with chronic kidney disease (CKD), and cardiovascular calcification (CVC) is one of the strongest predictors of CVD in this population. Cardiovascular calcification results from complex cellular interactions involving the endothelium, vascular/valvular cells (i.e., vascular smooth muscle cells, valvular interstitial cells and resident fibroblasts), and monocyte-derived macrophages. Indeed, the production of pro-inflammatory cytokines and oxidative stress by monocyte-derived macrophages is responsible for the osteogenic transformation and mineralization of vascular/valvular cells. However, monocytes/macrophages show the ability to modify their phenotype, and consequently their functions, when facing environmental modifications. This plasticity complicates efforts to understand the pathogenesis of CVC-particularly in a CKD setting, where both uraemic toxins and CKD treatment may affect monocyte/macrophage functions and thereby influence CVC. Here, we review (i) the mechanisms by which each monocyte/macrophage subset either promotes or prevents CVC, and (ii) how both uraemic toxins and CKD therapies might affect these monocyte/macrophage functions.

Uric acid variability at midlife as an independent predictor of coronary heart disease and all-cause mortality

Background

Serum uric acid (SUA) has long been associated with cardiovascular disease. Variability of serum uric acid (SUA) has seldom been examined in association with long-term morbidity and mortality. Therefore, we aimed to investigate the association between SUA variability and long-term all-cause and specific-cause mortality.

Methods

Among 10,059 men, aged 40–65, tenured civil servants and municipal employees in Israel, 8822 participants who were examined in 1963, 1965 and 1968 had assessment of diabetic and coronary morbidity status and SUA levels. We conducted analysis examining whether the standard deviations (SD) of Z-scores of SUA across study visits predicted coronary heart disease (CHD) and mortality. Hazard ratios (HR) associated with the SD of SUA-Z were calculated for stroke, CHD mortality and all-cause mortality associated with quartiles of the above variability.

Results

Multivariate analysis of 18-year CHD mortality yielded a significant association with the 1963–1968 SD of SUA-Z with age adjusted HR of CHD mortality of 0.97 (95% CI, 0.8–1.19), 1.05 (95% CI, 0.87–1.28) and 1.37 (95% CI, 1.15–1.65) for quartiles 2 to 4 respectively). The results of all-cause mortality similarly and strongly indicated increasing age-adjusted mortality risk with increasing SD of SUA-Z: HR = 1.08 (95% CI, 0.97–1.21), 1.15 (1.03–1.28) and 1.37 (1.23–1.51). No association was observed between the SD of SUA-Z and stroke mortality.

Conclusion

In this cohort of tenured male workers, with diverse occupations, higher variability of SUA measurement taken over 5 years was clearly predictive of 18-year CHD and all-cause mortality, above and beyond the SUA levels proper.

Serum Uric Acid Is Independently Associated with Coronary Calcification in an Asymptomatic Population

Detecting early-stage atherosclerosis is an important step towards cardiovascular disease prevention. Coronary artery calcium (CAC) score is a sensitive and non-invasive tool for detecting coronary atherosclerosis. Higher serum uric acid (SUA) levels are known to be associated with cardiovascular diseases. However, there is inconsistency regarding the independence of the association. The aim of our study was to assess the association of CAC and SUA in an asymptomatic population. CAC scans of 281 participants were analyzed in a voluntary screening program. A health questionnaire, physical examination, and laboratory tests were also performed. Participants with a history of cardiovascular disease were excluded from the analysis. 36.3% (n = 102) of the participants had no detectable CAC and 13.9% (n = 39) had a CAC score of > 300. SUA showed positive correlation with CAC score (0.175, p < 0.01). SUA was independently associated with Ca score > 300 (OR 5.17, p = 0.01) after the effects of conventional risk factors were eliminated.

Uric acid and cardiovascular disease

Uric acid (UA) is an end product of purine metabolism in humans and great apes. UA acts as an antioxidant and it accounts for 50% of the total antioxidant capacity of biological fluids in humans. When present in cytoplasm of the cells or in acidic/hydrophobic milieu in atherosclerotic plaques, UA converts into a pro-oxidant agent and promotes oxidative stress and through this mechanism participates in the pathophysiology of human disease including cardiovascular disease (CVD). Most epidemiological studies but not all of them suggested the existence of an association between elevated serum UA level and CVD, including coronary heart disease (CHD), stroke, congestive heart failure, arterial hypertension and atrial fibrillation as well as an increased risk for mortality due to CVD in general population and subjects with confirmed CHD. Evidence available also suggests an association between elevated UA and traditional cardiovascular risk factors, metabolic syndrome, insulin resistance, obesity, non-alcoholic fatty liver disease and chronic kidney disease. Experimental and clinical studies have evidenced several mechanisms through which elevated UA level exerts deleterious effects on cardiovascular health including increased oxidative stress, reduced availability of nitric oxide and endothelial dysfunction, promotion of local and systemic inflammation, vasoconstriction and proliferation of vascular smooth muscle cells, insulin resistance and metabolic dysregulation. Although the causality in the relationship between UA and CVD remains unproven, UA may be pathogenic and participate in the pathophysiology of CVD by serving as a bridging mechanism mediating (enabling) or potentiating the deleterious effects of cardiovascular risk factors on vascular tissue and myocardium.

Elevated serum uric acid predicts the development of moderate coronary artery calcification independent of conventional cardiovascular risk factors

BACKGROUND AND AIMS

Hyperuricemia was frequently noted in subjects with a high risk of cardiovascular disease (CVD). This study aimed to elucidate whether serum uric acid (SUA) is associated with development of moderate coronary artery calcification in generally healthy adults.

METHODS

A total of 9297 subjects underwent multidetector CT for the evaluation of CAC at least two times during their annual health examinations. Among them, 4461 participants without CVD history and who had no (scores 0) or minimal CAC (scores 1-10) in their first examination were enrolled. The association between SUA as a continuous and categorical variable and development of moderate coronary artery calcification (CAC score > 100) was assessed by Cox regression analysis. Receiver-operating characteristic (ROC) curves were constructed to investigate the diagnostic efficacy of SUA.

RESULTS

During a median follow-up of 4.1 years, 131 incident cases of moderate calcification developed. Baseline SUA concentration was significantly higher in subjects with progression to moderate coronary artery calcification (6.6 ± 1.3 vs. 5.8 ± 1.3 mg/dL, p < 0.001). SUA as a continuous variable (per 1 mg/dL) and divided into quartiles was positively associated with a higher risk of development of moderate calcification after adjustment for conventional CVD risk factors. The addition of SUA to the conventional CVD risk factors improved the predictive power for development of moderate coronary artery calcification.

CONCLUSIONS

SUA was an independent predictor for development of moderate coronary artery calcification in subjects with no or minimal calcification.

Silent Monosodium Urate Crystal Deposits Are Associated With Severe Coronary Calcification in Asymptomatic Hyperuricemia: An Exploratory Study

OBJECTIVE

To evaluate the association between monosodium urate (MSU) crystal deposits in patients with asymptomatic hyperuricemia and the severity and extension of coronary artery disease (CAD).

METHODS

In this cross-sectional study, consecutive inpatients with a non-ST elevation acute coronary event and asymptomatic hyperuricemia (serum uric acid concentration of ≥7.0 mg/dl) or normouricemia (serum uric acid concentration of <7.0 mg/dl) were enrolled. In patients with asymptomatic hyperuricemia, the presence of MSU crystals was determined by ultrasound evaluation of both knees and first metatarsophalangeal joints and by compensated polarized light microscopy. CAD was assessed by coronary angiography, and the following variables were considered: 1) the presence of moderate-to-severe coronary artery calcification, 2) the number of significant coronary stenoses, and 3) the presence of multivessel disease. The association between variables indicating the severity of CAD and the presence of MSU crystals was analyzed by multivariate regression.

RESULTS

One hundred forty patients were enrolled. After ultrasonography and microscopic analyses were performed, the patients were classified as having normouricemia (n = 66), asymptomatic hyperuricemia alone (n = 61), and asymptomatic hyperuricemia with MSU crystals (n = 13). The prevalence of moderate-to-severe coronary calcification was significantly higher in the patients with asymptomatic hyperuricemia with MSU crystals compared with patients with asymptomatic hyperuricemia alone and patients with normouricemia (P = 0.003). An independent association was observed between the presence of moderate-to-severe calcification and asymptomatic hyperuricemia with crystals (odds ratio 16.8, P = 0.002). No significant association was observed for the other variables.

CONCLUSION

Silent deposition of MSU crystals in patients with asymptomatic hyperuricemia was associated with more severe coronary calcification, which suggests more severe CAD in relation to crystal deposition.

Association Between Gout and Aortic Stenosis

BACKGROUND

An independent association between gout and coronary artery disease is well established. The relationship between gout and valvular heart disease, however, is unclear. The aim of this study was to assess the association between gout and aortic stenosis.

METHODS

We performed a retrospective case-control study. Aortic stenosis cases were identified through a review of outpatient transthoracic echocardiography (TTE) reports. Age-matched controls were randomly selected from patients who had undergone TTE and did not have aortic stenosis. Charts were reviewed to identify diagnoses of gout and the earliest dates of gout and aortic stenosis diagnosis.

RESULTS

Among 1085 patients who underwent TTE, 112 aortic stenosis cases were identified. Cases and nonaortic stenosis controls (n = 224) were similar in age and cardiovascular comorbidities. A history of gout was present in 21.4% (n = 24) of aortic stenosis subjects compared with 12.5% (n = 28) of controls (unadjusted odds ratio 1.90, 95% confidence interval 1.05-3.48, P = .038). Multivariate analysis retained significance only for gout (adjusted odds ratio 2.08, 95% confidence interval 1.00-4.32, P = .049). Among subjects with aortic stenosis and gout, gout diagnosis preceded aortic stenosis diagnosis by 5.8 ± 1.6 years. The age at onset of aortic stenosis was similar among patients with and without gout (78.7 ± 1.8 vs 75.8 ± 1.0 years old, P = .16).

CONCLUSIONS

Aortic stenosis patients had a markedly higher prevalence of precedent gout than age-matched controls. Whether gout is a marker of, or a risk factor for, the development of aortic stenosis remains uncertain. Studies investigating the potential role of gout in the pathophysiology of aortic stenosis are warranted and could have therapeutic implications.

Distribution of Serum Uric Acid in Black Africans and Its Association With Cardiovascular Risk Factors

Hyperuricemia is associated with cardiovascular disease and its prevalence is unknown in black Africans. This study reports hyperuricemia distribution and its association with cardiovascular risk factors in a selected Angolan population. A cross-sectional study in 585 black Africans was performed. Hyperuricemia was defined as uric acid >7.0 mg/dL in men or >5.7 mg/dL in women. Overall prevalence was 25%. Hyperuricemia was associated with hypertension (odds ratio [OR], 2.20; confidence interval [CI], 95% 1.41-3.47), high waist circumference (OR, 1.67; CI, 95% 1.05-2.65), and metabolic syndrome (OR, 1.66; CI, 95% 1.07-2.57). Compared to those with uric acid levels in the first quartile, individuals in the fourth quartile showed higher body mass index, waist circumference, systolic blood pressure, and plasma levels of creatinine and triglycerides. Hypertension, high waist circumference, and metabolic syndrome were the major cardiovascular risk factors associated with hyperuricemia.

Association between Serum Uric Acid and Mortality among Chinese Patients with Coronary Artery Disease

OBJECTIVES

Several studies have investigated the association between serum uric acid (SUA) and the risks of coronary artery disease (CAD) but have yielded inconsistent results. The aim of this study was to assess whether there is an independent association of SUA with all-cause and cardiovascular disease (CVD) mortality in Chinese patients with CAD.

METHODS

A prospective cohort study of 1,799 patients was conducted. Cox regression models were used to estimate the association of SUA with the risk of death.

RESULTS

During a median follow-up of 3.9 years, 177 deaths were recorded and 126 of these were due to CVD. Patients in the highest SUA quartile had a 2.43-fold risk of all-cause mortality and a 2.44-fold risk of CVD mortality compared with those in the lowest quartile. In the subpopulation analysis, the association between SUA and mortality remained similar when participants were stratified by age, gender, body mass index and type of CAD. In contrast, we found a significant interaction with estimated glomerular filtration rate (eGFR). There was a stronger association between SUA and the risk of all-cause and CVD mortality among patients with an eGFR ≥60 ml/min/1.73 m2, but no significant association was found in the population with an eGFR <60 ml/min/1.73 m2.

CONCLUSIONS

Elevated SUA levels were positively associated with an increased risk of all-cause and CVD mortality among CAD patients.