Uric acid and prognosis in angiography-proven coronary artery disease

A high level of uric acid is associated with long-term adverse cardiovascular outcomes in patients who received fractional flow reserve with coronary intermediate stenosis

BACKGROUND AND AIMS

The role of fractional flow reserve (FFR) in coronary intermediate lesions is widely recommended by guidelines. The effect of uric acid (UA) on cardiovascular events is also well known. However, the relationship between UA and long-term cardiovascular outcomes in patients who received FFR with intermediate lesions remains unknown.

METHODS AND RESULTS

We retrospectively included 428 patients who underwent both coronary angiography (CAG) and FFR. Participants were stratified into two groups based on the median UA. The primary endpoint was the composite of major adverse cardiovascular and cerebrovascular events (MACCEs), including repeat revascularization, nonfatal stroke, nonfatal myocardial infarction, and all-cause death. A Cox proportional hazards model was utilized to analyze the association between UA and the prevalence of MACCEs. During a median follow-up of 5.8 years, a higher MACCEs rate occurred in the high UA group compared to the low UA group (16.8% vs. 5.1%, p log-rank<0.01). Elevated UA was independently linked to a higher incidence of MACCEs, whether UA was treated as a categorical or continuous variable (hazard ratio [HR] 2.76, 95% confidence interval [CI] 1.27-6.03 or HR 1.01, 95% CI 1.01-1.02). The restricted cubic spline (RCS) analysis illustrated that the HR for MACCEs increased with increasing UA.

CONCLUSION

The present study demonstrates that UA is associated with MACCEs risk and suggests that UA is a reliable predictor of long-term cardiovascular events in coronary intermediate stenosis patients.

Serum uric acid predicts the development of atherosclerosis in women but not in men: A ten-year cohort study in China

BACKGROUND AND AIM

Atherosclerosis is becoming a significant health burden. Serum uric acid (SUA) is the final enzymatic product of purine metabolism and can contribute to the development of atherosclerosis. The aim of this study was to explore the possible predictive value of SUA in the development of atherosclerosis in a healthy Chinese population.

METHODS AND RESULTS

In this study, a total of 11,222 healthy subjects with no carotid plaque at baseline were enrolled and divided into sex-specific groups, and then the occurrence of carotid plaque during the follow-up time was documented. The association between carotid plaque and SUA levels was examined using Cox proportional-hazards regression models. The mean SUA level was 5.35 ± 1.41 mg/dL. A total of 2,911 individuals (25.94%) developed carotid plaque during the follow-up time, including 1,071 females and 1,840 males. After adjusting for potential confounding factors, the hazard ratio (HR) and 95% confidence interval (95% CI) in women for the occurrence of carotid plaque associated with SUA levels were 1.163 (1.017-1.330), but no significant correlation was found in men, as the HR was 1.050 (0.965-1.143).

CONCLUSION

Our results indicate that SUA levels predict the development of carotid plaque independent of traditional risk factors only in women.

Association between adherence to the Dietary Approaches to Stop Hypertension diet and serum uric acid

To explore the relationship between Dietary Approaches to Stop Hypertension (DASH) diet and serum uric acid (SUA) levels among the Chinese adult population, and verify the mediating effect of BMI between DASH diet and SUA levels. A total of 1125 adults were investigated using a self-administered food frequency questionnaire. SUA levels were determined by uricase colorimetry. The total DASH score ranged from 9 to 72. The relationship between the DASH diet and SUA levels was examined by multiple adjusted regression analysis. Method of Bootstrap was used to test the mediation effect of BMI in the correlation of the DASH diet and SUA levels. After multivariable adjustment, there was a significant linear relationship between the DASH diet and SUA (P < 0.001). Compared with the lowest group, SUA of participants in group of highest DASH diet score decreased by 34.907 (95% CI - 52.227, - 17.588; P trend < 0.001) μmol/L. The association between the DASH diet scores and SUA levels was partly mediated by BMI (- 0.26, Bootstrap 95% CI - 0.49, - 0.07), with 10.53% of the total effect being mediated. Adopting the DASH diet might be helpful in reducing SUA level, and the effect might be partly mediated by BMI.

Development and Validation of Nutrition Environment Scoring for Chinese Style University/Work-Site Canteens (NESC-CC) and Oil-Salt Visual Analogue Scale (OS-VAS)

The assessment of the use of cooking oil/fat and salt in dining food is an unsolved issue in non-quantitative nutrition environment evaluation, and the nutrition environment of Chinese-style dining establishments has not been effectively assessed. This study developed two evaluation tools: the Nutrition Environment Scoring for Chinese Style University/Work-site Canteens (NESC-CC) and the Oil-Salt Visual Analogue Scale (OS-VAS) and applied them in nine university canteens. The NESC-CC, which includes comprehensive items from the healthiness of food availability, cooking methods to other factors that support healthy choices, is featured by adjusting the scoring categories and items to suit Chinese food culture and canteen operation model. The OS-VAS is a novel virtual analog scale (VAS) based on the fuzzy judgement of the diners. It requires the randomly recruited respondents to rate their personal preference for salty taste/greasy food preference, overall saltiness/greasiness of canteen dishes, and personal demands for salt/cooking oil reduction. The oil use score, the salt use score, and the total score are derived from the given formula. The field tests of the NESC-CC in nine university canteens at three time points showed that this tool was able to effectively distinguish the nutrition environment of the Chinese food-style canteens with good reliability and validity. The result of OS-VAS scoring achieved a good resolution of the overall salt and oil/fat use and confirmed our hypothesis on the fuzzy judgement of the diners These tools are suitable for the comprehensive evaluation of Chinese-style canteens and have the potential to be applied to more group-meal-providing establishments.

Association of hyperuricemia with apolipoprotein AI and atherogenic index of plasma in healthy Chinese people: a cross-sectional study

BACKGROUND

The atherogenic index of plasma (AIP) is a predictor for cardiovascular diseases (CVD), while hyperuricemia is an independent risk factor for a variety of CVD. Apolipoprotein AI has been found to be a protective factor for CVD. However, the role of APO AI in the association between plasma uric acid and AIP among healthy Chinese people needs to be further explored.

AIMS

To evaluate the relationship between blood uric acid and AIP level in healthy Chinese people. To evaluate the relationship between blood uric acid and Apolipoprotein AI in healthy Chinese people.

METHOD

A total of 3501 normal and healthy subjects who had physical examinations were divided into the hyperuricemia (HUA) group and the normouricemia (NUA) group.

RESULT

The AIP of HUA group was significantly higher than that of NUA group [0.17±0.30 vs. -0.08±0.29]. Apo AI (1.33 ± 0.21 vs. 1.47 ± 0.26 g/l) and HDL-c (1.12 ± 0.27 vs. 1.36 ± 0.33 mmol/l) were significantly lower in the HUA group than in the NUA group. LDL-C (2.81 ± 0.77 vs. 2.69 ± 0.73 mmol/l), Apo B (0.96 ± 0.20 vs. 0.89 ± 0.20 g/l), FBG (5.48 ± 0.48 vs. 5.36 ± 0.48 mmol/l) and HOMA-IR [2.75 (1.92-3.91) vs. 2.18 (1.50-3.12)] was significantly higher in HAU group than the NUA group. Increases in plasma UA were associated with increases in AIP (β = 0.307, p < 0.01) and decreases in Apo AI (β =  - 0.236, p < 0.01).

CONCLUSION

Hyperuricemia is an independent risk factor for high AIP level. Inhibition of Apolipoprotein AI may be one of the mechanisms of UA which is involved in the progression of cardiovascular disease.

The U-Shaped Relationship Between Serum Uric Acid and Long-Term All-Cause Mortality in Coronary Artery Disease Patients: A Cohort Study of 33,034 Patients

Background

Associations between high serum uric acid (SUA) and cardiovascular diseases have been reported. However, few studies have been conducted to explore the relationship between SUA and long-term all-cause mortality in coronary artery disease (CAD) patients. Our study aims to investigate the relationship between SUA and long-term all-cause mortality in patients with CAD.

Methods

From January 2007 to December 2018, we divided 33,034 patients with CAD admitted in the Guangdong Provincial People's Hospital into five groups (quintile 1: SUA <5.05 mg/dl, quintile 2: 5.05 mg/dl ≤ SUA <5.59 mg/dl, quintile 3:5.59 mg/dl ≤ SUA <6.8 mg/dl, quintile 4, 6.8 mg/dl ≤ SUA <7.93 mg/dl, and quintile 5, SUA ≥7.93 mg/d;). This study used Kaplan–Meier survival analysis to evaluate patient outcomes with different ranges of SUA. Cox proportional hazards regression models and restricted cubic spline were applied to determine the association between serum uric and long-term all-cause mortality.

Results

A total of 33,034 participants were recruited, including 24,780 (75.01%) men and 8,254 (24.99) women in this cohort study. Median follow-up was 4.91 years. We found that SUA is an independent risk factor of long-term all-cause mortality according to the result of Cox proportional hazards models. This study also illustrated an approximate U-shape association between SUA and all-cause mortality when compared with 5.95 mg/lL ≤ SUA <6.8 mg/dl, SUA <5.0 5mg/dl (adjusted hazard ratio (aHR) =1.13, 95% CI: 1.01–1.26, p = 0.03), and SUA ≥8 mg/dL (aHR = 1.18, 95% CI: 1.06-1.32, p = 0.003).

Conclusion

Our study indicated a U-shaped relationship between SUA and long-term all-cause mortality in patients with CAD. No matter whether SUA is too high or too low, it increased the all-cause mortality in the CAD population, which deserves to be closely monitored.

Serum uric acid is an independent risk factor of worse mid- and long-term outcomes in patients with non-ST-segment elevation acute coronary syndromes

BACKGROUND

The data on the association between serum uric acid (sUA) concentration and outcomes in patients with an ACS are inconsistent and do not focus on patients with non-ST-segment elevation acute coronary syndromes (NSTE-ACS). The aim of this study was to analyze an association of sUA concentration on admission and outcomes in those patients.

METHODS

Data from the prospective, single-center registry of patients hospitalized due to NSTE-ACS from January 2006 to December 2016 were analyzed retrospectively. The population was divided into quartiles according to the baseline sUA. The primary outcome was the incidence of all-cause death, non-fatal myocardial infarction, stroke and ACS-driven revascularization at 36 months.

RESULTS

Total of 2,824 patients with sUA measured on admission were included in this analysis with a median sUA of 352 µmol/L (5.92 mg/dL). Patients with higher sUA were older and more burdened with cardiovascular risk factors and history of coronary events. The prevalence of multivessel coronary artery disease and left main stenosis was significantly higher in patients with higher sUA. Elevated sUA concentration was associated with significantly worse short-, mid- and long-term outcomes. All-cause mortality was significantly higher in each analyzed period. In the multivariable analysis, sUA elevation was identified as an independent predictor of all-cause mortality at 12-month and 36-month follow-up.

CONCLUSIONS

Elevated baseline sUA concentration was independently associated with worse mid- and long-term outcomes in patients with NSTE-ACS. Baseline sUA concentration could identify patients with NSTE-ACS at higher risk of more dismal prognosis.

The Role of Uric Acid in Acute and Chronic Coronary Syndromes

Uric acid (UA) is the final product of the catabolism of endogenous and exogenous purine nucleotides. While its association with articular gout and kidney disease has been known for a long time, new data have demonstrated that UA is also related to cardiovascular (CV) diseases. UA has been identified as a significant determinant of many different outcomes, such as all-cause and CV mortality, and also of CV events (mainly Acute Coronary Syndromes (ACS) and even strokes). Furthermore, UA has been related to the development of Heart Failure, and to a higher mortality in decompensated patients, as well as to the onset of atrial fibrillation. After a brief introduction on the general role of UA in CV disorders, this review will be focused on UA's relationship with CV outcomes, as well as on the specific features of patients with ACS and Chronic Coronary Syndrome. Finally, two issues which remain open will be discussed: the first is about the identification of a CV UA cut-off value, while the second concerns the possibility that the pharmacological reduction of UA is able to lower the incidence of CV events.

Hyperuricemia Predicts Adverse Outcomes After Myocardial Infarction With Non-obstructive Coronary Arteries

Background: Serum uric acid (SUA) is a well-known predictor of adverse outcomes in patients with various clinical conditions. However, the impact of SUA on patients with myocardial infarction with non-obstructive coronary arteries (MINOCA) remains unclear. Here, we aimed at investigating the potential association between hyperuricemia and the adverse outcomes in MINOCA patients. Methods: Overall, 249 MINOCA patients were enrolled in the present study. Clinical characteristics and laboratory data, were measured in all patients. Based on SUA levels, patients were classified into two groups; the hyperuricemia group [SUA level > 6 mg/dL (360 μmol/L) in women and > 7 mg/dL (420 μmol/L) in men], and the normuricemia group. The primary endpoint of our study was major adverse cardiac events (MACE), defined as cardiovascular death, stroke, heart failure, non-fatal MI, and angina rehospitalization. Results: Seventy-two patients were in hyperuricemia group and 177 in normuricemia group. Fifty-two MACE events were recorded after 30 months of follow-up period. The incidence of MACE was higher in hyperuricemia group compared with normuricemia group (31.9 vs. 16.3%, P = 0.006). Kaplan-Meier survival curves illustrated a significantly increased risk of MACE in hyperuricemia group (log-rank P = 0.006). The multivariable logistic analysis demonstrated that hyperuricemia was independently associated with a high risk of MACE after 30 months of follow-up (OR, 2.234; 95% CI, 1.054-4.737, P = 0.036). Conclusion: Hyperuricemia is associated with adverse outcomes and appears to be an independent predictor of MACE in MINOCA patients. This finding suggests that the SUA levels may serve as a surrogate biomarker related to risk prediction and adverse outcomes of MINOCA patients.

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.

Uric acid in chronic coronary syndromes: Relationship with coronary artery disease severity and left ventricular diastolic parameter

BACKGROUND AND AIMS

Uric Acid (UA) has been related to the development of Cardio-Vascular (CV) events in patients affected by Chronic Coronary Syndromes (CCS). Among various hypothesis, two arise: UA may negatively act on coronary artery determining a higher degree of atherosclerotic disease, and/or on heart determining a higher prevalence of diastolic dysfunction. Both the above hypothesized effects are object of our investigation.

METHODS AND RESULTS

231 patients who were admitted to the cardiological department of the Niguarda Hospital (Milan, Italy) for CCS from January 2017 to June 2018 were enrolled. Coronary atherosclerotic burden was evaluated from coronary angiography as the number and type of involved vessels, as well as with both Gensini and Syntax scores. All subjects underwent a complete echocardiogram. At unadjusted and adjusted/multivariable analysis, UA levels were not significantly associated with variables analysed from the coronary angiography (number and type of vessels involved, neither the Gensini and Syntax scores) as well as with echocardiographic parameters regarding systolic and diastolic function.

CONCLUSIONS

In conclusion, the main finding of our work is the absence of a role for UA in determining coronary arteries disease as well as LV diastolic dysfunction in CCS subjects. Taking together the results of previous studies with ours, we hypothesize that UA could act on heart (both on coronary arteries and on LV function) in an early phase of the disease, whereas while in the advanced stages other factors (previous myocardial infarction, previous myocardial revascularization and so on) may overshadow its effects.

Serum uric acid and fatal myocardial infarction: detection of prognostic cut-off values: The URRAH (Uric Acid Right for Heart Health) study

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Objective:

The Working Group on Uric Acid and Cardiovascular Risk of the Italian Society of Hypertension conceived and designed an ad-hoc study aimed at searching for prognostic cut-off values of serum uric acid (SUA) in predicting fatal myocardial infaction (MI) in women and men.

Methods:

The URic acid Right for heArt Health study is a nationwide, multicentre, observational cohort study involving data on individuals aged 18–95 years recruited on a regional community basis from all the territory of Italy under the patronage of the Italian Society of Hypertension with a mean follow-up period of 122.3 ± 66.9 months.

Results:

A total of 23 467 individuals were included in the analysis. Cut-off values of SUA able to discriminate MI status were identified by mean of receiver operating characteristic curves in the whole database (>5.70 mg/dl), in women (>5.26 mg/dl) and in men (>5.49 mg/dl). Multivariate Cox regression analyses adjusted for confounders (age, arterial hypertension, diabetes, chronic kidney disease, smoking habit, ethanol intake, BMI, haematocrit, LDL cholesterol and use of diuretics) identified an independent association between SUA and fatal MI in the whole database (hazard ratio 1.381, 95% confidence intervals, 1.096–1.758, P = 0.006) and in women (hazard ratio 1.514, confidence intervals 1.105–2.075, P < 0.01), but not in men.

Conclusion:

The results of the current study confirm that SUA is an independent risk factor for fatal MI after adjusting for potential confounding variables, and demonstrate that a prognostic cut-off value associated to fatal MI can be identified at least in women.

An old friend: uric acid and its association with fractional flow reserve

Background/aim

The aim of this study was to investigate the importance of preprocedural uric acid (UA) level in predicting fractional flow reserve (FFR) results of intermediate coronary lesions in patients with stable coronary artery disease undergoing coronary angiography.

Materials and methods

We retrospectively analyzed 293 patients who underwent FFR measurement to determine the significance of intermediate coronary stenosis detected by conventional coronary angiography. Patients were divided into 2 groups: Group 1 (n = 127) included patients with FFR of <0.80 (hemodynamically significant lesions), and Group 2 (n = 169) consisted of patients with FFR of >0.80 (hemodynamically nonsignificant lesions). Uric acid levels were assessed in both groups with the enzymatic colorimetric method by clinical chemistry autoanalyzer.

Results

The mean UA level was significantly higher in patients whose FFR indicated hemodynamically significant coronary lesions (UA: 5.43 ± 1.29 mg/dL in Group 1 vs. 4.51 ± 1.34 mg/dL in Group 2, P < 0.001).

Conclusion

Elevated UA levels are associated with hemodynamically significant coronary lesions measured with FFR. Uric acid may be used as a predictor of hemodynamically compromised coronary lesions before FFR procedures.

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.

Effects of a Dietary Approach to Stop Hypertension (DASH) Diet Intervention on Serum Uric Acid in African Americans With Hypertension

OBJECTIVE

To examine whether partial replacement of a diet typical of the average American diet with Dietary Approaches to Stop Hypertension (DASH)-related foods in the home environment lowers the serum uric acid (UA) level in individuals with hypertension.

METHODS

We conducted an ancillary study of a randomized trial of African American adults with controlled hypertension from an urban clinic. Participants were assigned to either a control group or an intervention (DASH-Plus) group. DASH-Plus participants received coach-directed dietary advice, assistance with purchasing DASH-related foods ($30/week), and home delivery of food via a community supermarket. Participants in the control group received a DASH diet brochure and a debit card account ($30/week) to purchase foods. Serum UA levels were measured at baseline and after 8 weeks.

RESULTS

Of the original 123 randomized participants, 117 had available serum UA measurements. Seventy percent of the participants were women, the mean ± SD age was 59 ± 9.5 years, and the mean ± SD serum UA level was 6.4 ± 1.7 mg/dl. The DASH-Plus diet did not reduce serum UA levels compared with the control diet (difference in difference -0.01 mg/dl [95% confidence interval -0.39, 0.38]). However, there was a significant trend toward a greater reduction in the serum UA level in participants with higher baseline serum UA levels (P for trend = 0.008). Baseline changes in the serum UA level were inversely associated with changes in systolic blood pressure (P = 0.002), diastolic blood pressure (P = 0.001), and urinary sodium excretion (P = 0.05).

CONCLUSION

Overall, in African American individuals, partial replacement of a typical diet with DASH foods did not lower serum UA levels compared with a control diet. However, there was a significant trend toward a greater reduction in serum UA levels in subjects with higher baseline serum UA levels. Furthermore, changes in serum UA levels were associated with known correlates, suggesting heterogeneity of effects in the treatment and control arms. Future pragmatic studies of consumption of the DASH diet to lower serum UA levels should optimize replacement strategies and enroll individuals with hyperuricemia or gout.

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.

Effect of Salt Intake on Plasma and Urinary Uric Acid Levels in Chinese Adults: An Interventional Trial

Uric acid (UA) has been proposed as an important risk factor for cardiovascular and renal morbidity. We conducted an interventional trial to assess effects of altered salt intake on plasma and urine UA levels and the relationship between UA levels and salt sensitivity in humans. Ninety subjects (18–65 years old) were sequentially maintained on a normal diet for 3 days at baseline, a low-salt diet for 7 days (3.0 g/day, NaCl), and a high-salt diet for an additional 7 days (18.0 g/day of NaCl). Plasma UA levels significantly increased from baseline to low-salt diet and decreased from low-salt to high-salt diet. By contrast, daily urinary levels of UA significantly decreased from baseline to low-salt diet and increased from low-salt to high-salt diet. The 24 h urinary sodium excretions showed inverse correlation with plasma UA and positive correlation with urinary UA excretions. Additionally, salt-sensitive subjects presented significantly higher plasma UA changes in comparison to salt-resistant subjects, and a negative correlation was observed between degree of salt sensitivity and plasma UA difference. The present study indicates that variations in dietary salt intake affect plasma and urine UA levels, and plasma UA may be involved in pathophysiological process of salt sensitivity.

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.

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.

Effects of the Dietary Approaches to Stop Hypertension (DASH) Diet and Sodium Intake on Serum Uric Acid

OBJECTIVE

Randomized trial data guiding dietary recommendations to lower serum uric acid (UA), the etiologic precursor of gout, are scarce. We undertook this study to examine the effects of the Dietary Approaches to Stop Hypertension (DASH) diet (a well-established diet that lowers blood pressure) and levels of sodium intake on serum UA.

METHODS

We conducted an ancillary study of a randomized, crossover feeding trial in 103 adults with prehypertension or stage I hypertension. Participants were randomly assigned to receive either the DASH diet or a control diet (typical of the average American diet) and were further fed low, medium, and high levels of sodium for 30 days, each in random order. Body weight was kept constant. Serum UA levels were measured at baseline and following each feeding period.

RESULTS

Trial participants were 55% women and 75% black with a mean ± SD age of 51.5 ± 9.7 years and a mean ± SD serum UA level of 5.0 ± 1.3 mg/dl. The DASH diet reduced serum UA (-0.35 mg/dl [95% confidence interval (95% CI) -0.65, -0.05], P = 0.02), with a higher effect (-1.29 mg/dl [95% CI -2.50, -0.08]) among participants (n = 8) with a baseline serum UA level of ≥7 mg/dl. Increasing sodium intake from the low level decreased serum UA during the medium sodium intake period (-0.3 mg/dl [95% CI -0.5, -0.2], P < 0.001) and during the high sodium intake period (-0.4 mg/dl [95% CI -0.6, -0.3], P < 0.001).

CONCLUSION

The DASH diet lowered serum UA, and this effect was greater among participants with hyperuricemia. Moreover, we found that higher sodium intake decreased serum UA, which enhances our knowledge of urate pathophysiology and risk factors for hyperuricemia.

Uric acid is associated with vascular dementia in Chinese population

OBJECTIVE

Mounting evidence suggests that oxidative stress is involved in the pathogenesis of vascular dementia (VD). Uric acid (UA) has long been implicated as a critical cause of cardiovascular disease. Nevertheless, UA was also expected to play an important role in antioxidant and neuroprotection recently. We hypothesized that UA may have a protective role against VD. The aim of this study was to investigate the link between serum UA and cognitive dysfunction in VD.

MATERIALS AND METHODS

There were altogether 127 VD subjects and 81 nondemented controls enrolled in our study. Serum UA, demographic, and clinical characteristics were recorded at baseline, and all participants underwent Mini-Mental State Examination (MMSE) at the beginning of the trial.

RESULTS

The VD group showed lower MMSE scores and serum UA levels than nondemented controls and there was significant statistical difference between the two groups (p < .05). Demographic and clinical characteristics such as age, gender, education, body mass index (BMI), total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL), low-density lipoprotein cholesterol (LDL), blood urea nitrogen (BUN), and serum creatinine (Scr) did not differ dramatically between groups (p > .05). In VD subjects, there was a positive correlation between serum UA and MMSE scores (r = .32, p < .05), and this correlation was independent of demographic and clinical characteristics (β = .272, p < .05).

CONCLUSIONS

VD subjects have dramatically lower serum UA levels in comparison to nondemented controls. Lower serum UA levels are linked to cognitive dysfunction and could serve as a potential predictor for VD.

Opposing effects of sodium intake on uric acid and blood pressure and their causal implication

Reducing uric acid is hypothesized to lower blood pressure, although evidence is inconsistent. In this ancillary of the DASH-Sodium trial, we examined whether sodium-induced changes in serum uric acid (SUA) were associated with changes in blood pressure. One hundred and three adults with prestage or stage 1 hypertension were randomly assigned to receive either the DASH diet or a control diet (typical of the average American diet) and were fed each of the three sodium levels (low, medium, and high) for 30 days in random order. Body weight was kept constant. SUA was measured at baseline and following each feeding period. Participants were 55% women and 75% black. Mean age was 52 (SD, 10) years, and mean SUA at baseline was 5.0 (SD, 1.3) mg/dL. Increasing sodium intake from low to high reduced SUA (-0.4 mg/dL; P < .001) but increased systolic (4.3 mm Hg; P < .001) and diastolic blood pressure (2.3 mm Hg; P < .001). Furthermore, changes in SUA were independent of changes in systolic (P = .15) and diastolic (P = .63) blood pressure, regardless of baseline blood pressure, baseline SUA, and randomized diet, as well as sodium sensitivity. Although both SUA and blood pressure were influenced by sodium, a common environmental factor, their effects were in opposite directions and were unrelated to each other. These findings do not support a consistent causal relationship between SUA and BP.

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.

Relationship of non-cardiac biomarkers with periprocedural myocardial injury in patients undergoing percutaneous coronary intervention

percutaneous coronary intervention (PCI) is one of the dominant methods for revascularization in patient with coronary artery disease (CAD), which accompanied with high incidence of periprocedural myocardial injury (PMI) evaluated by postprocedural cardiac biomarker elevation. For the convenience of risk stratification of PMI following PCI, the aim of present review provides a unique opportunity to summarize the relationship of non-cardiac biomarkers with PMI by extensively searching in the MEDLINE to identify all the relevant studies. In conclusion, we found that PCI related PMI might be correlated positively to those non-cardiac biomarkers such as low-density lipoprotein cholesterol (LDL-C), non-high-density lipoprotein cholesterol, total cholesterol, triglyceride, the ratios of LDL-C to high-density lipoprotein cholesterol (HDL-C), the ratios of HDL-C to apolipoprotein A-I, the ratio of eicosapentaenoic acid to arachidonic acid, lectin-like oxidized low-density lipoprotein receptor-1, C-reactive protein, high on-treatment platelet reactivity, platelet-monocyte aggregates, N-term pro-B-type natriuretic peptide, hemoglobin and albuminuria. Inversely, no relationships of PMI with those non-cardiac biomarkers such as mean platelet volume, platelet distribution width, platelet-larger cell ratio, uric acid, eosinophils count and the genetic variant of methylenetetrahydrofolate reductase (MTHFR) 677 C>T polymorphism. Moreover, there were controversial associations between PMI and those non-cardiac biomarkers such as high-density lipoprotein cholesterol, glycosylated hemoglobin, homocysteine and the polymorphism Leu33Pro of platelet glycoprotein IIbIIIa. However, almost all studies failed to provide definite mechanism of its findings, and further reaches are needed to focus on the potential mechanisms of association between non-cardiac biomarkers and PMI related to PCI.

Associations of the uric acid related genetic variants in SLC2A9 and ABCG2 loci with coronary heart disease risk

Background

Multiple studies investigated the associations between serum uric acid and coronary heart disease (CHD) risk. However, further investigations still remain to be carried out to determine whether there exists a causal relationship between them. We aim to explore the associations between genetic variants in uric acid related loci of SLC2A9 and ABCG2 and CHD risk in a Chinese population.

Results

A case–control study including 1,146 CHD cases and 1,146 controls was conducted. Association analysis between two uric acid related variants (SNP rs11722228 in SLC2A9 and rs4148152 in ABCG2) and CHD risk was performed by logistic regression model. Adjusted odds ratios (ORs) with 95% confidence intervals (CIs) were calculated. Compared with subjects with A allele of rs4148152, those with G allele had a decreased CHD risk and the association remained significant in a multivariate model. However, it altered to null when BMI was added into the model. No significant association was observed between rs11722228 and CHD risk. The distribution of CHD risk factors was not significantly different among different genotypes of both SNPs. Among subjects who did not consume alcohol, the G allele of rs4148152 showed a moderate protective effect. However, no significant interactions were observed between SNP by CHD risk factors on CHD risk.

Conclusions

There might be no association between the two uric acid related SNPs with CHD risk. Further studies were warranted to validate these results.

Electronic supplementary material

The online version of this article (doi:10.1186/s12863-015-0162-7) contains supplementary material, which is available to authorized users.

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.

A cross-sectional analysis of the relationship between uric acid and coronary atherosclerosis in patients with suspected coronary artery disease in China

Background

Although many studies have examined the relationship between uric acid (UA) and coronary artery disease (CAD), whether UA is an independent risk factor contributing to progression of CAD is still controversial. Whether UA plays a different role in different sexes is also unclear.

Methods

A total of 1116 individuals with suspected CAD were stratified into four groups according to their serum UA quartiles in total (men and women combined), in men, and in women. The association of UA with coronary atherosclerosis was assessed by univariable and multivariable logistic regression.

Results

In total and in women, the prevalence of any plaques and significant/severe stenosis was significantly increased with an increase in quartiles of UA (all P < 0.05). The proportion of triple-vessel disease and left main artery lesion was highest in the fourth quartile (both p < 0.05). Increasing quartiles of UA were significantly associated with a coronary artery calcium score (CACS) >10 (all P < 0.01). As UA levels increased in women, the incidence of double-vessel lesions (p = 0.017) and the proportion of mixed plaques (p = 0.022) were significantly increased. The proportion of a CACS of 0 in total, in men and women was highest in the first quartile (all P < 0.01). UA was the strongest predictor of significant stenosis, multivessel disease, and mixed plaques in women (all p < 0.05). UA was the only risk factor for mixed plaques in total (P = 0.046).

Conclusion

The level of UA was significantly associated with coronary atherosclerosis in women, but not men.

Uric acid and risk of periprocedural myocardial infarction in patients undergoing percutaneous coronary intervention

BACKGROUND

Periprocedural myocardial infarction still occurs in patients undergoing percutaneous coronary intervention. However, very little is known about the role of biomarkers possibly predicting this complication. Serum uric acid has been associated with enhanced inflammatory status, higher thrombotic risk and poorer outcome after percutaneous coronary intervention. We therefore, evaluated the association between uric acid levels and periprocedural myocardial infarction in patients undergoing percutaneous coronary intervention.

METHODS

We evaluated 1272 consecutive patients undergoing percutaneous coronary intervention. We measured myonecrosis biomarkers at intervals from 8 to 48 h after percutaneous coronary intervention. Periprocedural myonecrosis was defined as a troponin I increase by 3 times the upper limit normal (ULN) or by 50% of an elevated baseline value and periprocedural myocardial infarction as creatine kinase-Myocardial Band increase by 3 times the ULN or 50% of baseline.

RESULTS

Patients were divided according to tertile values of uric acid (< 5.40, ≥ 6.70 mg/dL). Serum uric acid was related to age, male gender, hypertension, smoking, renal failure (p < 0.001), previous coronary artery bypass grafts (p = 0.05), therapy with ACE inhibitors (p = 0.001) and diuretics (p < 0.001), glycaemia (p = 0.001), creatinine (p < 0.001), haemoglobin (p = 0.002) and white blood cells (p = 0.02). Serum uric acid was inversely related to type C lesions (p = 0.03) and coronary thrombus (p = 0.02). SUA did not affect the risk of periprocedural myocardial infarction (p = 0.29; adjusted odds ratio = 1.11[0.93-1.32], p = 0.26) or periprocedural myonecrosis (p = 0.97; adjusted odds ratio = 0.99[0.86-1.14], p = 0.89). Results were confirmed at subgroup analyses of higher-risk subsets of patients.

CONCLUSION

This is the first large study showing that serum uric acid is not associated with an increase in the risk of periprocedural myocardial infarction in patients undergoing percutaneous coronary revascularization.

Serum uric acid and the risk of mortality during 23 years follow-up in the Scottish Heart Health Extended Cohort Study

BACKGROUND

Elevated uric acid is a prevalent condition with controversial health consequences. Observational studies disagree with regard to the relationship of uric acid with mortality, and with factors modifying this relationship.

OBJECTIVE

We examined the association of serum uric acid with mortality in 15,083 participants in the Scottish Heart Health Extended Cohort (SHHEC) Study.

METHODS

Serum uric acid was measured at study enrollment. Death was ascertained using both the Scottish death register and record linkage.

RESULTS

During a median follow-up of 23 years, there were 3980 deaths. In Cox proportional hazards models with sexes combined, those in the highest fifth of uric acid had significantly greater mortality (HR 1.18, 95% CI: 1.06, 1.31) compared with the second fifth, after adjustment for traditional cardiovascular risk factors. This relationship was modified by sex (P-interaction=0.002) with adjusted HRs of 1.69 (95% CI: 1.40, 2.04) and 0.99 (95% CI: 0.86, 1.14) in women and men, respectively. Compared with the second fifth, the highest fifth of uric acid was most associated with kidney-related death (HR: 2.08, 95% CI: 1.31, 3.32).

CONCLUSION

Elevated uric acid is associated with earlier mortality, especially in women. Future studies should evaluate mechanisms for these interactions and explore the strong association with renal-related mortality.

Relationship of serum uric Acid level and angiographic severity of coronary artery disease in male patients with acute coronary syndrome

Background and objective: The association between serum uric acid and ischemic heart disease remains controversial and it has not yet been established as cardiovascular risk factor. Our objective was to study the association of serum uric acid level with angiographic severity of coronary artery disease in men with acute coronary syndrome (ACS).

Methods: This cross-sectional study was conducted on 100 consecutive male patients presenting with ACS at Punjab Institute of Cardiology. Hyperuricemia was defined as serum uric acid level > 6.5 mg/dl. Severity of ischemic heart disease was assessed on the basis of Gensini score, number of diseased vessels, critical lesions and total occlusions on coronary angiogram.

Results: Mean age of normouricemic group (n=59) was 52.62 ± 9.46 years and mean age of hyperuricemic group (n=41) was 50.52 ± 9.40 years (p=0.273). Mean uric acid level; normouricemic group (4.75 ± 1.05), hyperuricemic group (7.61 ± 1.24), p<0.001. Mean Gensini score; normouricemic group (22.15 ± 21.52), hyperuricemic group (35.69 ± 26.80). Mann Whitney U test was applied to compare the Gensini score of two groups and it showed statistically significant difference (p value <0.006). Critical lesions, total occlusions and multi-vessel disease were more frequent in hyperuricemic group but statistically significant difference was found only for total occlusions (p=0.013) and critical lesions (p=0.046).

Conclusions: Hyeruricemia is associated with higher Gensini score and more frequent total occlusions and critical lesions in men presenting with acute coronary syndrome.

A gender-specific analysis of association between hyperuricaemia and cardiovascular events in patients with coronary artery disease

BACKGROUND AND AIMS

Gender-related differences in the association between hyperuricaemia and cardiovascular events remain poorly understood. The objective of this study was to assess gender-related differences in the association between hyperuricaemia and cardiovascular events in patients with coronary artery disease (CAD).

METHODS AND RESULTS

This study included 13,273 patients with CAD. Hyperuricaemia was defined as a plasma uric acid >7.0mgdl(-1) in men and >5.7mgdl(-1) in women. The primary outcome was 1-year all-cause mortality. Hyperuricaemia was found in 3745 men (36.5%) and 1562 women (50.3%); odds ratio (OR)=1.76, 95% confidence interval (CI) 1.62-1.91; P<0.001. Women with hyperuricaemia were older, had higher proportions of patients with diabetes and arterial hypertension and had reduced renal function and higher C-reactive protein levels compared with men with hyperuricaemia. One-year all-cause mortality was 9.3% (n=143) in women with hyperuricaemia versus 6.9% (n = 252) in men with hyperuricaemia (P=0.002). After adjustment in multivariable Cox proportional hazards model, uric acid predicted 1-year mortality with an adjusted hazard ratio (HR)=1.17, 95% CI (1.03-1.31), P=0.012 in men and HR=1.25, 95% CI (1.06-1.48), P=0.007 in women, for each standard deviation increase in the natural logarithm. Uric acid predicted 1-year mortality with an area under the receiver-operating characteristic curve=0.625, 95% CI (0.594-0.656) in men and 0.676, 95% CI (0.635-0.717) in women (P=0.044, for women versus men).

CONCLUSION

Hyperuricaemia predicts an increased risk of 1-year mortality in both genders with a stronger association in women. Differences in cardiovascular risk profile may explain the stronger association between hyperuricaemia and cardiovascular events in women.