Serum uric acid as an independent predictor of mortality in high-risk patients with obstructive coronary artery disease: a prospective observational cohort study from the ET-CHD registry, 1997-2003

Uric acid to albumin ratio as a novel predictor for coronary slow flow phenomenon in patients with chronic coronary syndrome and non-obstructive coronary arteries

BACKGROUND

The plasma uric acid to albumin ratio (UAR) is considered as a novel indicator for Inflammation. However, the association between UAR and coronary slow flow phenomenon (CSFP) remains unclear.

METHODS

A total of 1328 individuals with chronic coronary syndrome (CCS) receiving coronary angiography (CAG) and found no obvious obstructive stenosis (< 40%) were included in this study. 79 individuals developed CSFP and were divided into CSFP group. The 1:2 age-matched patients with normal coronary blood flow were allocated to the control group (n = 158). The clinical characteristics, laboratory parameters including uric acid, albumin ratio, UAR and the angiographic characteristics were compared between the two groups.

RESULTS

Patients with CSFP had a higher level of uric acid (392.3 ± 85.3 vs. 273.8 ± 71.5, P < 0.001), UAR (10.7 ± 2.2 vs. 7.2 ± 1.9, P < 0.001), but a lower level of plasma albumin (36.9 ± 4.2 vs. 38.5 ± 3.6, P = 0.003). Moreover, UAR increased as the numbers of vessels involved in CSFP increased. The logistic regression analysis demonstrated that UAR was independent predictors for CSFP. The Receiver operating characteristic (ROC) curve analysis showed that when UAR was more than 7.9, the AUC was 0.883 (95% CI: 0.840-0.927, p < 0.001), with the sensitivity and specificity were 78.2% and 88.2% respectively.

CONCLUSION

Combined uric acid with plasma albumin, UAR could serve as an independent predictor for CSFP.

Association of serum uric acid with anemia in U.S. adults: a cross-sectional study using secondary data

BACKGROUND

High serum uric acid (SUA) is a risk factor of cardiovascular disease (CVD). Abnormal SUA have been correlated with a significant increase in mortality. Anemia is an independent predictor of mortality and CVD. To date, no study has investigated the relationship between SUA and anemia. Here, we explored the correlation between SUA and anemia in the American population.

METHODS

The cross-sectional study involved 9205 US adults from NHANES (2011-2014). The relationship between SUA and anemia was explored using multivariate linear regression models. Two-piecewise linear regression model, generalized additive models (GAM) and smooth curve fitting were performed to explore the non-linear relationships between SUA and anemia.

RESULTS

We found a U-shaped non-linear relationship between SUA and anemia. The inflection point of the SUA concentration curve was 6.2 mg/dL. The ORs (95% CIs) for anemia on the left and right of the inflection point were 0.86 (0.78-0.95) and 1.33 (1.16-1.52), respectively. The 95% CI of inflection point was 5.9-6.5 mg/dL. The findings showed that both genders presented a U-shaped correlation. Safe ranges of SUA in men and women were 6-6.5 and 4.3-4.6 mg/dL, respectively.

CONCLUSIONS

Both high and low SUA levels were correlated with increased risk of anemia, and a U-shaped relationship was observed between SUA and anemia.

The Prognostic Significance of Uric Acid/Albumin Ratio in Patients with Aortic Stenosis Following Transcatheter Aortic Valve Implantation for Major Adverse Cardiac and Cerebral Events

Background: The goal of this study was to examine if the uric acid/albumin ratio (UAR) could predict major adverse cardiac and cerebral events (MACCEs) such as stroke, readmission, and short-term all-cause death in aortic stenosis (AS) patients, after transcatheter aortic valve implantation (TAVI). Material and Methods: A total of 150 patients who had TAVI for AS between 2013 and 2022 were included in our study, retrospectively. Before the TAVI, each patient’s baseline uric acid/albumin was determined. The study’s major endpoint was MACCEs, which included stroke, re-hospitalization, and 12-month all-cause death. Results: The UAR was found to be higher in TAVI patients who developed MACCEs than in those who did not develop them. Multivariate Cox regression analysis revealed that the UAR (HR: 95% CI; 2.478 (1.779–3.453) p < 0.01), was an independent predictor of MACCEs in AS patients after TAVI. The optimal value of the UAR for MACCEs in AS patients following TAVI was >1.68 with 88% sensitivity and 66% specificity (AUC (the area under the curve): 0.899, p < 0.01). We noted that the AUC of UAR in predicting MACCEs was significantly higher than the AUC of albumin (AUC: 0.823) and uric acid (AUC: 0.805, respectively). Conclusion: MACCEs in AS patients who received TAVI may be predicted by high pre-procedural uric acid/albumin levels. The uric acid/albumin ratio (UAR) can be used to determine MACCEs in such patients following TAVI because it is inexpensive and straightforward to calculate inflammatory parameters.

Hyperuricemia predicts increased cardiovascular events in patients with chronic coronary syndrome after percutaneous coronary intervention: A nationwide cohort study from Japan

Background

The causal relationship between hyperuricemia and cardiovascular diseases is still unknown. We hypothesized that hyperuricemic patients after percutaneous coronary intervention (PCI) had a higher risk of major adverse cardiovascular events (MACE).

Methods

This was a large-scale multicenter cohort study. We enrolled patients with chronic coronary syndrome (CCS) after PCI between April 2013 and March 2019 using the database from the Clinical Deep Data Accumulation System (CLIDAS), and compared the incidence of MACE, defined as a composite of cardiovascular death, myocardial infarction, and hospitalization for heart failure, between hyperuricemia and non-hyperuricemia groups.

Results

In total, 9,936 patients underwent PCI during the study period. Of these, 5,138 patients with CCS after PCI were divided into two group (1,724 and 3,414 in the hyperuricemia and non-hyperuricemia groups, respectively). The hyperuricemia group had a higher prevalence of hypertension, atrial fibrillation, history of previous hospitalization for heart failure, and baseline creatinine, and a lower prevalence of diabetes than the non-hyperuricemia group, but the proportion of men and age were similar between the two groups. The incidence of MACE in the hyperuricemia group was significantly higher than that in the non-hyperuricemia group (13.1 vs. 6.4%, log-rank P < 0.001). Multivariable Cox regression analyses revealed that hyperuricemia was significantly associated with increased MACE [hazard ratio (HR), 1.52; 95% confidential interval (CI), 1.23-1.86] after multiple adjustments for age, sex, body mass index, estimated glomerular filtration rate, left main disease or three-vessel disease, hypertension, diabetes mellitus, dyslipidemia, history of myocardial infarction, and history of hospitalization for heart failure. Moreover, hyperuricemia was independently associated with increased hospitalization for heart failure (HR, 2.19; 95% CI, 1.69-2.83), but not cardiovascular death or myocardial infarction after multiple adjustments. Sensitive analyses by sex and diuretic use, B-type natriuretic peptide level, and left ventricular ejection fraction showed similar results.

Conclusion

CLIDAS revealed that hyperuricemia was associated with increased MACE in patients with CCS after PCI. Further clinical trials are needed whether treating hyperuricemia could reduce cardiovascular events or not.

High-level uric acid in asymptomatic hyperuricemia could be an isolated risk factor of cardio-cerebrovascular diseases: A prospective cohort study

BACKGROUND AND AIMS

Whether the asymptomatic hyperuricemia (AH) raise the cardiovascular disease risk with or without hyperuricemia-related comorbidities still remains contentious. Our study was aimed to quantitatively access the incidence risk of coronary heart disease (CHD) and stroke associated with AH.

METHODS AND RESULTS

In this prospective cohort study, multivariate-adjusted Cox regression models were applied to evaluate the risk of cardiovascular disease (CVD). Baseline serum uric acid beyond normouricemia (357 mmol/L) was quarterly stratified based on the distribution of healthy populations without CVD onset. 1062 CVD first-attack cases were collected among the 29,974 study population (age range: 18-91, mean age: 47.2 ± 13.9 years-old) with a mean follow-up duration of 5.78 ± 0.83 years. The AH showed overall non-association with the CVD incident. However, significantly increased adjusted hazard ratio (HR) of CVD with 95% confidence interval (CI) were observed when the fourth quartile compared with normouricemia stratum in the total cohort population (CHD: 1.42, 1.21-1.68; stroke: 1.27, 1.06-1.41), male (CHD: 1.26, 1.12-1.55), female (CHD: 1.34, 1.04-2.02; stroke: 2.06, 1.13-3.77) and aged over 50 years-old population. Meanwhile, the age-standardized incidence rate of CVD in the fourth quartile was 2-3 times higher than the normouricemia population. After excluded 14,464 baseline population with diabetes, dyslipidemia, and hypertension, consistent results were also observed in the AH population in absence of comorbidities (CHD: 1.51, 1.22-2.25; stroke: 1.68, 1.13-2.39).

CONCLUSION

Asymptomatic hyperuricemia patients exposed to a higher level of uric acid (>=428 mmol/L) could significantly increase the incidence risk of CHD and stroke, with or without hyperuricemia-related comorbidities.

Uric Acid-to-Albumin Ratio: A Novel Marker for the Extent of Coronary Artery Disease in Patients with Non-ST-Elevated Myocardial Infarction

OBJECTIVE

This research aimed to investigate the predictive value of the uric acid-to-serum albumin ratio (UAR) in establishing the severity and extent of coronary artery disease (CAD) with non-ST segment elevation myocardial infarction (NSTEMI) patients.

METHODS

A total of 402 patients (mean age 63.5 ± 11.6 years) were included in this retrospectively designed study. We compared Synergy between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery Scores (SS) between low (≤22) and intermediate-high (>22) groups. The UAR, the neutrophil-to-lymphocyte ratio (NLR), and the C-reactive protein-to-albumin ratio (CAR) were evaluated and compared.

RESULTS

SS >22 were observed in 30.8% (n = 124) of the patients, and their UAR, NLR, and CAR were significantly higher. Three separate multivariate analysis models performed as the outcome of a reliable correlation between UAR, NLR, CAR, and consequently UAR (OR = 2.08; 95% CI 1.21-3.58; p = 0.008) and CAR (OR = 3.33; 95% CI 1.85-5.9; p < 0.001) reached significance but NLR (OR = 1.26; 95% CI 0.86-1.84; p = 0.20) clinically trended significance (not statistically). Model performance comparisons demonstrated that UAR is a better predictor regarding likelihood ratios (UAR, 60.95; NLR, 57.8; and CAR, 59.0).

CONCLUSION

As a novel inflammatory marker, UAR independently predicted better outcomes than CAR and might be used reliably in prediction of the extent of CAD in NSTEMI patients.

Asymptomatic Hyperuricemia and Metabolically Unhealthy Obesity: A Cross-Sectional Analysis in the Tianning Cohort

OBJECTIVE

The relationship between obesity and hyperuricemia has been demonstrated by many studies. However, whether or to what extent metabolic condition influents the association between obesity and hyperuricemia was not clear. Here, we aimed to examine the association between obese-metabolic phenotype and hyperuricemia in a large sample of Chinese adults.

METHODS

According to BMI and metabolic syndrome, obese-metabolic phenotype was defined as metabolically unhealthy obesity (MUO), metabolically healthy obesity (MHO), metabolically unhealthy non-obesity (MUNO) and metabolically healthy non-obesity (MHNO)in the Tianning cohort (N=5072). We conducted a cross-sectional analysis between obese-metabolic phenotype and hyperuricemia, followed by a Mendelian Randomization analysis using GWAS summary data to confirm the causality between uric acid and BMI.

RESULTS

The average level of serum UA showed 41.87-higher μmol/L in participants with MHO (β=41.87, P<0.001) and 63.18-higher μmol/L in participants with MUO (β=63.18, P<0.001), compared to those with MHNO. Compared to participants with MHNO, those with MUO had the highest likelihood to have hyperuricemia (OR=4.56, P<0.001), followed by those with MHO (OR=3.32, P<0.001). Mendelian randomization analysis indicated that uric acid was more likely to be a consequence of BMI (β=0.059, P=6.54×10^-154).

CONCLUSION

MUO, in comparison with MHO, was significantly associated with hyperuricemia in Chinese adults.

Metabolic biomarkers and long-term blood pressure variability in military young male adults

BACKGROUND

Metabolic syndrome is a cluster of cardiovascular risk factors, including central obesity, high blood pressure, elevated plasma glucose, reduced high-density lipoprotein and elevated triglyceride levels.

AIM

To investigate the relationship between metabolic biomarkers and long-term blood pressure variability (BPV) in young males.

METHODS

A cohort of 1112 healthy military males aged 18-40 years from the cardiorespiratory fitness and hospitalization events in armed forces study in eastern Taiwan was prospectively included. The following metabolic biomarkers were used: Waist circumference, serum uric acid (SUA), triglycerides, high density lipoprotein, triglycerides, and fasting glycose. BPV was assessed by average real variability (ARV) and standard deviation (SD) across 4 clinic visits during the study period (2012-14, 2014-15, 2015-16, and 2016-18). Multivariable linear regression analysis was used to determine the association after adjusting for age, body mass index, systolic and diastolic blood pressure (SBP and DBP), lipid profiles, physical activity, alcohol intake and tobacco smoking status.

RESULTS

In the unadjusted model, waist circumference was significantly and positively correlated with ARV_DBP and SD_DBP [β (standard errors) = 0.16 (0.049) and 0.22 (0.065), respectively], as was SUA [β = 0.022 (0.009) and 0.038 (0.012), respectively]. High-density lipoprotein was negatively correlated with ARV_SBP [β = −0.13 (0.063)]. There were no associations with the other metabolic biomarkers. In contrast, only SUA was significantly correlated with SD_SBP and SD_DBP [β = 0.019 (0.011) and 0.027 (0.010), respectively] in the adjusted model.

CONCLUSION

Our findings showed that of traditional metabolic biomarkers, SUA had the strongest positive correlation with long-term systolic and diastolic BPV in young male adults, and the clinical relevance needs further investigation.

Generalized Pharmacometric Modeling, a Novel Paradigm for Integrating Machine Learning Algorithms: A Case Study of Metabolomic Biomarkers

There is an unmet need for identifying innovative machine learning (ML) strategies to improve drug treatment regimens and therapeutic outcomes. We investigate Generalized Pharmacometric Modeling (GPM), a novel paradigm that integrates ML algorithms with pharmacokinetic and pharmacodynamic structural models, population covariate modeling, and "big data," and enables identification of patient-specific factors contributing to drug disposition. We hypothesize that GPM will enhance forecasting of drug outcomes in diverse populations. We assessed random forest regression in conjunction with Bayesian networks as the ML methods within GPM and used the National Health and Nutrition Examination Survey population-based study database. GPM was utilized to identify subject-specific factors associated with cholesterol dynamics. Our results demonstrate the utility of GPM to enhance pharmacometrics modeling and its potential for modeling drug outcomes in diverse populations.

Serum uric acid and risk of cardiovascular mortality: a systematic review and dose-response meta-analysis of cohort studies of over a million participants

Background

Cardiovascular disease (CVD) is the leading cause of death worldwide. Some studies have suggested anassociation between serum uric acid levels and cardiovascular mortality; however, the results have not been summarized in a meta-analysis.

Methods

A comprehensive search of all related studies until April 2018was performed in MEDLINE/PubMed and Scopus databases DerSimonianand Laird random-effects models were used to combine hazard ratios (HRs) with 95% confidence intervals (CIs). Dose-response analysis was also carried out.

Results

Thirty-two studies containing forty-four arms with 1,134,073 participants reported association between uric acid and risk of CVD mortality were included in our analysis. Pooled results showed a significant positive association between uric acid levels and risk of CVD mortality (HR 1.45, 95% CI 1.33–1.58, I² = 79%). Sub-group analysis showed this relationshipwasstronger in women compared to men. Moreover, there was a significant non-linear association between uric acid levels and the risk of CVD mortality (r = 0.0709, p = 0.001).

Conclusion

Our analysis indicates a positive dose-response association between SUA and CVD mortality risk.

Sex-Specific Association Between Serum Uric Acid and Elevated Alanine Aminotransferase in a Military Cohort: The CHIEF Study

AIM

The study was conducted in order to examine the sex-specific association of serum uric acid (SUA) levels with elevated serum alanine aminotransferase (ALT) in a Taiwanese military cohort.

METHODS

We made a cross-sectional examination of the sex-specific relationship using 6728 men and 766 women, aged 18-50 years from a large military cohort in Taiwan. SUA levels within the reference range (<7.0 mg/dL for men and <5.7 mg/dL for women respectively) were divided into quartiles and SUA levels greater than the upper reference limits were defined as hyperuricemia. Elevated ALT levels were defined as ≥40 U/L. Multivariate logistic regression analysis was performed to determine the association between each SUA category and elevated ALT levels in men and women, respectively.

RESULTS

The prevalence of hyperuricemia and elevated ALT in men were 18.7% and 12.7%, respectively, and in women were 3.3% and 2.1%, respectively. As compared with the lowest SUA quartile, hyperuricemia was associated with elevated ALT in men (odds ratios (OR): 1.62, 95% confidence intervals (CI): 1.19-2.20) after controlling for age, service specialty, body mass index, metabolic syndrome components, current cigarette smoking, alcohol intake status, and weekly exercise times, but the associations for the other SUA quartiles were null. By contrast, the associations of hyperuricemia (OR: 0.81, 95% CI: 0.10-6.64) and the other SUA quartiles with elevated ALT were null in women.

CONCLUSION

Our findings suggest that the relationship between each SUA level and elevated ALT may differ by sex among military young adults. The mechanism for the sex difference requires further investigations.

Serum Uric Acid Could Differentiate Acute Myocardial Infarction and Unstable Angina Pectoris in Hyperuricemic Acute Coronary Syndrome Patients

Introduction:

Serum uric acid (SUA) is the final product of purine metabolism in humans.

Aim:

The present study aimed to identify a potential association between serum UA and cardiac troponin I (cTnI) levels and to find out whether uric acid could differentiate patients presenting with the acute myocardial infarction (AMI) and unstable angina pectoris (UAP) in hyperuricemic and normouricemic acute coronary syndrome (ACS) patients.

Methods:

Eighty ACS patients, aged 50-83 years, were enrolled in the study, 40 of them presenting with AMI and 40 with UAP. Frequency of patients with serum uric level over threshold for hyperuricemia was investigated and two groups of patients were formed such as hyperuricemic and normouricemic groups (A and B groups, respectively) independently of type of ACS. Those groups of patients were also subjected to cTnI measurement.

Results:

Levels of SUA are associated with the type of ACS in the hyperuricemic ACS patients (AMI versus UAP, 499(458-590), 425(400-447) mmol/L, p=0.007, respectively). Uric acid correlated significantly with cTnI, moderate positively in the group A (rho=0.358, p=0.038) and moderate negatively in the group B (r=-0.309, p=0.037) of ACS patients. Multiple logistic regression analysis revealed that cTnI and age were independently associated with the SUA levels in the group A of ACS patients.

Conclusions:

Serum uric acid differentiates AIM and UAP patients in hyperuricemic group of acute coronary syndrome. Therefore it can be used as nonspecific parameter for evaluation of the myocardial lesion extent only in hyperuricemic ACS patients. This is supported by finding that cTnI along with age predicts SUA level in hyperuricemic ACS patients.

Hyperuricemia is Associated with Increased Apo AI Fractional Catabolic Rates and Dysfunctional HDL in New Zealand Rabbits

The potential cause-effect relationship between uric acid plasma concentrations and HDL functionality remains elusive. Therefore, this study aimed to explore the effect of oxonic acid (OA)-induced hyperuricemia on the HDL size distribution, lipid content of HDL subclasses, and apo AI turnover, as well as HDL functionality in New Zealand white rabbits. Experimental animals received OA 750 mg/kg/day by oral gavage during 21 days. The HDL-apo AI fractional catabolic rate (FCR) was determined by exogenous labeling with ¹²⁵I, and HDL subclasses were determined by sequential ultracentrifugation and PAGE. Paraoxonase-1 activity (PON-1) and the effect of HDL on relaxation of aorta rings in vitro were determined as an indication of HDL functionality. Oxonic acid induced a sixfold increase of uricemia (0.84 ± 0.06 vs. 5.24 ± 0.12 mg/dL, P < 0.001), and significant decreases of triglycerides and phospholipids of HDL subclasses, whereas HDL size distribution and HDL-cholesterol remained unchanged. In addition, HDL-apo AI FCR was significantly higher in hyperuricemic rabbits than in the control group (0.03697 ± 0.0038 vs. 0.02605 ± 0.0017 h^-1 respectively, P < 0.05). Such structural and metabolic changes were associated with lower levels of PON-1 activities and deleterious effects of HDL particles on endothelium-mediated vasodilation. In conclusion, hyperuricemia is associated with structural and metabolic modifications of HDL that result in impaired functionality of these lipoproteins. Our data strongly suggest that uric acid per se exerts deleterious effects on HDL that contribute to increase the risk of atherosclerosis.

Elevated serum uric acid and risk of cardiovascular or all-cause mortality in people with suspected or definite coronary artery disease: A meta-analysis

BACKGROUND AND AIMS

Serum uric acid (SUA) has been recognized as an independent risk factor for mortality in the general population. We performed this meta-analysis to determine whether elevated SUA levels are associated with greater risk of cardiovascular or all-cause mortality in people with suspected or definite coronary artery disease (CAD).

METHODS

The Pubmed and Embase databases were searched up to April 1, 2016 for the longitudinal studies that investigated the association between the elevated SUA and cardiovascular or all-cause mortality risk in people with suspected or definite CAD. Pooled adjusted risk ratio (RR) and corresponding 95% confidence interval (CI) were calculated for the highest vs. the lowest SUA category or each 1 mg/ml SUA rise.

RESULTS

Nine studies enrolling 25,229 participants were included in the analyses. The highest vs. lowest SUA category was associated with greater risk of cardiovascular mortality (RR 2.09; 95% CI: 1.45-3.02) and all-cause mortality (RR 1.80; 95% CI: 1.39-2.34) after adjustment for potential confounders in a random effects model. Moreover, each 1 mg/ml SUA rise significantly increased by 12% cardiovascular mortality and by 20% all-cause mortality.

CONCLUSIONS

Elevated SUA levels are strongly and independently associated with greater risk of cardiovascular and all-cause mortality in people with suspected or definite CAD.

Comparison of the effects of metoprolol or carvedilol on serum gamma-glutamyltransferase and uric acid levels among patients with acute coronary syndrome without ST segment elevation

Objective:

Serum gamma-glutamyltransferase (GGT) and uric acid levels measured in patients with acute coronary syndrome without ST segment elevation (NSTEMI) are important in diagnosis and in predicting the prognosis of the disease. There is a limited number of clinical studies investigating the effects of beta-blockers on GGT and uric acid levels in these patients. In our study, we aimed to investigate the effects of beta-blocker therapy on GGT and uric acid levels.

Methods:

We conducted a randomized, prospective clinical study. Hundred patients with NSTEMI were included in this study, and they were divided into two groups. Fifty patients were administered metoprolol succinate treatment (1 × 50 mg), whereas the remaining 50 patients were administered carvedilol treatment (2 × 12.5 mg). Thereafter, all of the patients underwent coronary angiography. Blood samples were taken at the time of admission, at the 1^st month, and 3^rd month to detect GGT and uric acid levels.

Results:

There was no statistically significant difference among the metoprolol or carvedilol groups in terms of the GGT levels measured at the baseline, 1^st month, and 3^rd month (p=0.904 and p=0.573, respectively). In addition, there was no statistically significant difference among the metoprolol or carvedilol groups in terms of uric acid levels measured at the baseline, 1^st month, and 3^rd month (p=0.601 and p=0.601, respectively).

Conclusion:

We found that GGT and uric acid levels did not show any change compared to the baseline values, with metoprolol and carvedilol treatment initiated in the early period in patients with NSTEMI.

Uric Acid and Cardiovascular Events: A Mendelian Randomization Study

Obesity and diets rich in uric acid-raising components appear to account for the increased prevalence of hyperuricemia in Westernized populations. Prevalence rates of hypertension, diabetes mellitus, CKD, and cardiovascular disease are also increasing. We used Mendelian randomization to examine whether uric acid is an independent and causal cardiovascular risk factor. Serum uric acid was measured in 3315 patients of the Ludwigshafen Risk and Cardiovascular Health Study. We calculated a weighted genetic risk score (GRS) for uric acid concentration based on eight uric acid-regulating single nucleotide polymorphisms. Causal odds ratios and causal hazard ratios (HRs) were calculated using a two-stage regression estimate with the GRS as the instrumental variable to examine associations with cardiometabolic phenotypes (cross-sectional) and mortality (prospectively) by logistic regression and Cox regression, respectively. Our GRS was not consistently associated with any biochemical marker except for uric acid, arguing against pleiotropy. Uric acid was associated with a range of prevalent diseases, including coronary artery disease. Uric acid and the GRS were both associated with cardiovascular death and sudden cardiac death. In a multivariate model adjusted for factors including medication, causal HRs corresponding to each 1-mg/dl increase in genetically predicted uric acid concentration were significant for cardiovascular death (HR, 1.77; 95% confidence interval, 1.12 to 2.81) and sudden cardiac death (HR, 2.41; 95% confidence interval, 1.16 to 5.00). These results suggest that high uric acid is causally related to adverse cardiovascular outcomes, especially sudden cardiac death.

Depletion of Uric Acid Due to SLC22A12 (URAT1) Loss-of-Function Mutation Causes Endothelial Dysfunction in Hypouricemia

BACKGROUND

Uric acid (UA) serves as an antioxidant in vascular endothelial cells. UA transporter 1 (URAT1) encoded by SLC22A12 is expressed in the kidney and vessels and its loss of function causes hypouricemia. The purpose of this study was to examine whether there is any endothelial dysfunction in patients with hypouricemia.

METHODS AND RESULTS

Twenty-six patients with hypouricemia (<2.5 mg/dl) and 13 healthy control subjects were enrolled. Endothelial function was evaluated using flow-mediated dilation (FMD). mRNA of UA transporters expressed in cultured human umbilical endothelial cells (HUVEC) was detected on RT-PCR. There was a positive correlation between FMD and serum UA in the hypouricemia group. URAT1 loss-of-function mutations were found in the genome of 21 of 26 patients with hypouricemia, and not in the other 5. In the hypouricemia groups, serum UA in homozygous and compound heterozygous patients was significantly lower than in other groups, suggesting that severity of URAT1 dysfunction may influence the severity of hypouricemia. Thirteen of 16 hypouricemia subjects with homozygous and compound heterozygote mutations had SUA <0.8 mg/dl and their FMD was lower than in other groups. HUVEC do not express mRNA of URAT1, suggesting the null role of URAT1 in endothelial function.

CONCLUSIONS

Depletion of UA due to SLC22A12/URAT1 loss-of-function mutations causes endothelial dysfunction in hypouricemia patients.

Lipoprotein subfractions partly mediate the association between serum uric acid and coronary artery disease

BACKGROUND

Serum uric acid (SUA) has been established to be highly associated with coronary artery disease (CAD) susceptibility and lipid metabolism, but the underlying mechanisms are unclear. Recently, lipoprotein subfractions have been proposed to be more valuable in CAD risk evaluation. Hence, we sought to investigate whether the relationship between SUA and CAD is partly mediated by lipoprotein subfractions.

METHODS

A total of 401 consecutive subjects undergoing coronary angiography were enrolled. The baseline clinical data including the SUA level and lipid profiles were collected. The lipoprotein subfractions were determined using the Lipoprint system.

RESULTS

In the overall population, the upper SUA quintiles had significantly higher atherogenic lipid parameters and unbalanced lipoprotein subfractions especially higher small dense low-density lipoprotein-cholesterol (sdLDL-C) and lower large high-density lipoprotein-cholesterol (HDL-C) (p<0.05). The levels of SUA and lipoprotein subfractions were dramatically different between male and female. After adjusting for traditional risk factors including gender, multivariate linear regression analysis suggested that SUA was positively associated with sdLDL-C (β=0.113, p=0.013) but negatively related to large HDL-C level (β=-0.152, p=0.002). Given the significant association of the SUA level with lipoprotein subfractions and incident CAD (adjusted OR=1.312, 95% CI 1.069-1.609, p=0.009), we performed the mediation analyses and found that 8.7-10.5% of the effect of SUA on CAD susceptibility was mediated by the increased sdLDL-C or decreased large HDL-C level (p<0.05).

CONCLUSIONS

The SUA level was proved to be associated with lipoprotein subfractions including sdLDL-C (positive) and large HDL-C (negative), which partly mediated the association between SUA and CAD susceptibility.

Association of serum uric acid and coronary artery disease in premenopausal women

Objective

To date, no study in the published literature has investigated the role of various serum uric acid (SUA) concentrations in the development of angiographically-proven coronary artery disease (CAD) in premenopausal women. Therefore, the aim of this study was to investigate the role SUA levels may play in the prevalence, severity, and prognosis of CAD in premenopausal women.

Methods

This cross-sectional retrospective study included 607 premenopausal women who had undergone coronary angiography. The CAD diagnosis was based upon stenosis affecting ≥50% of the luminal diameter. Association of the SUA levels with CAD prevalence, severity, and clinical outcomes were assessed by statistical analysis.

Results

In total, 369 (60.8%) of the patients were diagnosed with CAD. The CAD patients had significantly higher SUA levels than those without CAD (5.3±1.9 vs. 4.8±1.7 mg/dL, P = 0.001). The SUA levels were found to be significantly associated with CAD prevalence (P = 0.013). Patients with higher levels of SUA also showed increased rates of multivessel disease and composite end-points, such as major adverse cardiac events. Furthermore, multivariate analysis identified abnormally high levels of uric acid (hyperuricemia) as an independent risk factor for CAD (OR 1.51 (1.11–2.53), P<0.05).

Conclusions

The SUA levels are significantly associated with the prevalence of CAD. The SUA levels may be a predictor for incidence of major cardiovascular events in premenopausal women.

Relation of serum uric acid and body mass index to mortality in high-risk patients with established coronary artery disease: a report from the ET-CHD registry, 1997-2006

BACKGROUND

Hyperuricemia is associated with a higher risk of death in patients with coronary artery disease (CAD). In contrast, overweight or obesity was associated with survival benefits in this population. However, the relation of body mass index (BMI) and serum uric acid (SUA) to mortality has not been clarified in this population.

METHODS

We studied a cohort of 1202 patients with angiographic CAD from the ET-CHD registry during 1997-2003 in Taiwan. To evaluate the relation of BMI and SUA on mortality, the subjects were categorized into 4 groups by BMI >/= 25 kg/m(2) (overweight or obesity) or BMI<25 kg/m(2) (normal- or under-weight), and SUA levels higher or lower than the median of 6.6 mg/dl. At a median follow-up of 5.4 years, cardiac and all-cause deaths were the primary end points.

RESULTS

Multivariate analyses demonstrated that high SUA group had a significantly higher cardiac mortality [hazard ratio (HR): 1.79, 95% confidence interval (CI): 1.14-2.82, p=0.023] and overall mortality (HR: 1.68, 95% CI: 1.19-2.36, p=0.003) than low SUA group only in overweight or obese patients. Additionally, high BMI was associated with a significantly lower cardiac mortality (HR: 0.58, 95% CI: 0.38-0.99, p=0.023) and overall mortality (HR: 0.62, 95% CI: 0.41-0.82, p=0.003) than low BMI in patients with low SUA levels. Furthermore, normal-low weight and underweight patients (BMI<21 kg/m(2)) were found to have a higher risk of mortality regardless of SUA levels.

CONCLUSIONS

Among patients with established CAD, SUA may be a potent predictor to mortality in overweight or obese patients. Moreover, the obesity-mortality paradox phenomenon was mainly driven by higher mortality risk in underweight patients and lower mortality risk in overweight and obese patients with low SUA.

Relation of estimated glomerular filtration rate and body mass index to mortality in non-dialysis patients with coronary artery disease: a report from the ET-CHD registry, 1997-2003

BACKGROUND

Low estimated glomerular filtration rate (eGFR) and body mass index (BMI) have been known as poor prognostic factors in patients with coronary artery disease (CAD). Besides, high BMI was associated with higher survival rate in patients on dialysis as well. However, the relation of eGFR and BMI to mortality has not been clarified in non-dialysis CAD patients.

METHODS

We studied a cohort of 1243 non-dialysis patients with angiographic CAD from the ET-CHD registry during 1997-2003 in Taiwan. To evaluate the relation of eGFR and BMI to mortality, the subjects were categorized into 4 groups by BMI higher or lower than 25 kg/m2 and eGFR higher or lower than 60 mL/min/1.73 m2, a cut-off value for chronic kidney disease (CKD). At a mean follow-up of 5.4 years, cardiac and all-cause deaths were the primary end points.

RESULTS

In the high BMI group, CKD was a strong predictor of cardiac and overall mortality [hazard ratio (HR): 1.63 (95% CI: 1.05-2.53) and 2.17 (95% CI: 1.54-3.07), respectively]. Besides, CKD marginally elevated the mortality risk in the low BMI group. Among CKD patients, BMI was not associated with mortality except for a high death rate in patients with BMI lower than 21 kg/m2. In contrast, in non-CKD patients, high BMI group had a lower cardiac and overall mortality than the low BMI group [HR: 0.75 (95% CI: 0.48-1.16) and 0.55 (95% CI: 0.39-0.77), respectively].

CONCLUSIONS

Among non-dialysis CAD patients in eastern Taiwan, lower eGFR was associated with worse prognosis regardless of BMI levels. Notably, in patients with high BMI, the relationship between CKD and mortality was extremely remarkable. Moreover, the obesity-mortality paradox phenomenon was not present in non-dialysis CKD patients.

Gender differences in the impact of diabetes on mortality in patients with established coronary artery disease: a report from the eastern Taiwan integrated health care delivery system of Coronary Heart Disease (ET-CHD) registry, 1997-2006

OBJECTIVES

The effect of type 2 diabetes mellitus (DM) on mortality was more pronounced in women than men with coronary artery disease (CAD) in the pre-stent era before 1996. However this relationship is controversial in the post-stent era.

METHODS

We studied a cohort of 1073 patients with angiographically defined CAD from the Eastern Taiwan integrated health care delivery system of Coronary Heart Disease (ET-CHD) registry during 1997-2003 in Tzu-Chi General Hospital, Hualien, Taiwan. To evaluate gender-specific DM effect on mortality, the subjects were divided into 4 groups: diabetic women (n=147), non-diabetic women (n=127), diabetic men (n=239), and non-diabetic men (n=560). At a mean follow-up of 5.4 years, cardiac and all-cause mortality were the primary end points.

RESULTS

Annual total mortality rates were 10.2%, 5.1%, 7.2%, and 4.8%; annual cardiac mortality rates were 8.2%, 3.0%, 4.3%, and 2.6% for diabetic women, non-diabetic women, diabetic men, and non-diabetic men, respectively. Multivariate Cox regression models, adjusted for possible confounders showed that gender-specific hazard ratios (HRs) of DM for total mortality were 2.02 (95% CI: 1.32-3.09), and 1.72 (95% CI: 1.32-2.25) for women and men, respectively. The HRs for total mortality associated with diabetes were not different between women and men (p=0.53). Similarly, adjusted gender-specific HRs of DM for cardiac mortality were 2.46 (95% CI: 1.45-4.19) for women, and 1.83 (95% CI: 1.28-2.62) for men, which were also not significantly different (p=0.36).

CONCLUSIONS

Among patients with CAD, the impact of DM on mortality was consistently higher in women than in men, but the differences across sexes were not statistically significant after 1996 in Taiwan.