Exploration into Uric and Cardiovascular Disease: Uric Acid Right for heArt Health (URRAH) Project, A Study Protocol for a Retrospective Observational Study

A Cohort Study on the Correlation Between Serum Uric Acid Trajectory and New-Onset Hypertension Based on Longitudinal Health Examination Data in Henan Area

Objective

To explore the correlation between serum uric acid (SUA) trajectories and new-onset hypertension, to provide scientific basis for the prevention and treatment of hypertension.

Methods

The study cohort was composed of 4372 subjects who met the inclusion criteria in the cohort study of Henan physical examination population. According to the SUA values of the subjects' physical examination from 2017 to 2019, three different SUA trajectory groups were determined by R LCTM tools, namely low stability group, medium stability group and high stability group. The incidence of hypertension during physical examination in 2020 was followed up, the cumulative incidence rate in each group was calculated by product limit method, and the correlation between different SUA trajectories and new-onset hypertension was analyzed by Cox proportional hazards regression model.

Results

The incidence rate of hypertension increased with the increase of SUA locus, which was 4.65%, 9.18% and 12.43% respectively, and the difference was statistically significant (P<0.001). After adjusting multiple confounding factors, such as gender, waist circumference (WC), blood pressure, body mass index (BMI), fasting plasma glucose (FPG) and blood lipid by Cox proportional hazards regression model, the risk of hypertension in SUA medium stability and high stability group was still 1.476 times (95% CI: 1.089~2.000) and 1.692 times (95% CI: 1.152~2.484) of low-stable SUA group (P<0.05).

Conclusion

The risk of hypertension increases with the increase of SUA level in the long-term normal range. It is necessary to carry out the intervention for hypertension with long-term normal high value to avoid the progress of hypertension disease, to achieve the purpose of early prevention of hypertension.

Prognostic Value and Relative Cutoffs of Triglycerides Predicting Cardiovascular Outcome in a Large Regional-Based Italian Database

BACKGROUND

Despite longstanding epidemiologic data on the association between increased serum triglycerides and cardiovascular events, the exact level at which risk begins to rise is unclear. The Working Group on Uric Acid and Cardiovascular Risk of the Italian Society of Hypertension has conceived a protocol aimed at searching for the prognostic cutoff value of triglycerides in predicting cardiovascular events in a large regional-based Italian cohort.

METHODS AND RESULTS

Among 14 189 subjects aged 18 to 95 years followed-up for 11.2 (5.3-13.2) years, the prognostic cutoff value of triglycerides, able to discriminate combined cardiovascular events, was identified by means of receiver operating characteristic curve. The conventional (150 mg/dL) and the prognostic cutoff values of triglycerides were used as independent predictors in separate multivariable Cox regression models adjusted for age, sex, body mass index, total and high-density lipoprotein cholesterol, serum uric acid, arterial hypertension, diabetes, chronic renal disease, smoking habit, and use of antihypertensive and lipid-lowering drugs. During 139 375 person-years of follow-up, 1601 participants experienced cardiovascular events. Receiver operating characteristic curve showed that 89 mg/dL (95% CI, 75.8-103.3, sensitivity 76.6, specificity 34.1, P<0.0001) was the prognostic cutoff value for cardiovascular events. Both cutoff values of triglycerides, the conventional and the newly identified, were accepted as multivariate predictors in separate Cox analyses, the hazard ratios being 1.211 (95% CI, 1.063-1.378, P=0.004) and 1.150 (95% CI, 1.021-1.295, P=0.02), respectively.

CONCLUSIONS

Lower (89 mg/dL) than conventional (150 mg/dL) prognostic cutoff value of triglycerides for cardiovascular events does exist and is associated with increased cardiovascular risk in an Italian cohort.

Temporal relationship between elevated serum uric acid levels and dyslipidemia: A 5-year cohort study using cross-lagged panel analysis

BACKGROUND AND AIM

Previous studies have demonstrated an association between SUA and dyslipidemia. This study aims to explore the temporal relationship between SUA and dyslipidemia.

METHODS AND RESULTS

Based on the Beijing Health Management Cohort conducted from 2013 to 2018, the data of a physical examination population was collected, including a total of 6630 study subjects. Cross-lagged panel analysis was employed to examine the temporal relationship between elevated SUA levels and dyslipidemia, indicated by either elevated TG or decreased HDL-C. The path coefficient and the 95 % CI from baseline TG to follow-up SUA were as follows: in the general population, men, women, and people with BMI ≥25 kg/m2were 0.027 (0.008-0.045), 0.024 (0.001-0.048), 0.032 (0.001-0.063) and 0.033 (0.006-0.059) (P < 0.05); however, the path coefficient from baseline SUA to follow-up TG and the 95 % CI were not statistically significant. Furthermore, the path coefficients and 95 % CIs between elevated SUA and decreased HDL-C were not statistically significant, both in the general population and in populations stratified by gender and BMI.

CONCLUSIONS

We found a temporal relationship from elevated TG to elevated SUA in the general population and the populations stratified by gender and BMI (≥25 kg/m2). However, we did not observe a reverse relationship from elevated SUA to elevated TG. Additionally, we did not find a temporal relationship between decreased HDL-C and elevated SUA in both the general population and the stratified populations.

The Results of the URRAH (Uric Acid Right for Heart Health) Project: A Focus on Hyperuricemia in Relation to Cardiovascular and Kidney Disease and its Role in Metabolic Dysregulation

The relationship between Serum Uric Acid (UA) and Cardiovascular (CV) diseases has already been extensively evaluated, and it was found to be an independent predictor of all-cause and cardiovascular mortality but also acute coronary syndrome, stroke and heart failure. Similarly, also many papers have been published on the association between UA and kidney function, while less is known on the role of UA in metabolic derangement and, particularly, in metabolic syndrome. Despite the substantial number of publications on the topic, there are still some elements of doubt: (1) the better cut-off to be used to refine CV risk (also called CV cut-off); (2) the needing for a correction of UA values for kidney function; and (3) the better definition of its role in metabolic syndrome: is UA simply a marker, a bystander or a key pathological element of metabolic dysregulation?. The Uric acid Right for heArt Health (URRAH) project was designed by the Working Group on uric acid and CV risk of the Italian Society of Hypertension to answer the first question. After the first papers that individuates specific cut-off for different CV disease, subsequent articles have been published responding to the other relevant questions. This review will summarise most of the results obtained so far from the URRAH research project.

Serum uric acid and left ventricular mass index independently predict cardiovascular mortality: The uric acid right for heart health (URRAH) project

A relationship between serum uric acid (SUA) and cardiovascular (CV) events has been documented in the Uric Acid Right for Heart Health (URRAH) study.

AIM

of this study was to investigate the association between SUA and left ventricular mass index (LVMI) and whether SUA and LVMI or their combination may predict the incidence of CV death.

METHODS

Subjects with echocardiographic measurement of LVMI included in the URRAH study (n=10733) were part of this analysis. LV hypertrophy (LVH) was defined as LVMI > 95 g/m2 in women and 115 g/m2 in men.

RESULTS

A significant association between SUA and LVMI was observed in multiple regression analysis in men: beta 0,095, F 5.47, P< 0.001 and women: beta 0,069, F 4.36, P<0.001. During follow-up 319 CV deaths occurred. Kaplan-Meier curves showed a significantly poorer survival rate in subjects with higher SUA (> 5.6 mg/dl in men and 5.1 mg/dl in women) and LVH (log-rank chi-square 298.105; P<0.0001). At multivariate Cox regression analysis in women LVH alone and the combination of higher SUA and LVH but not hyperuricemia alone, were associated with a higher risk of CV death, while in men hyperuricemia without LVH, LVH without hyperuricemia and their combination were all associated with a higher incidence of CV death.

CONCLUSIONS

Our findings demonstrate that SUA is independently associated with LVMI and suggest that the combination of hyperuricemia with LVH is an independent and powerful predictor for CV death both in men and women.

Serum Uric Acid Levels Are Associated with the Echogenic Features of Carotid Plaque Vulnerability in Elderly Patients with Atherosclerotic Disease

Uric acid is a marker of inflammation and a risk factor for atherosclerosis that has been suggested to play a role in carotid plaque instability. Reduced atherosclerotic plaque echogenicity at ultrasound examination is associated with alarming histopathological features and inflammation. In this study, we investigated the relationship between serum uric acid (SUA) levels and echogenic patterns of plaque instability in elderly subjects with carotid atherosclerosis. Since uric acid metabolism largely depends on renal function, SUA levels were indexed for serum creatinine levels (SUA/SCr). We enrolled 108 patients aged 65 years or more (72.7 ± 5.9 years; 50 females and 58 males) who underwent carotid duplex ultrasound to evaluate plaque echogenicity by greyscale median (GSM). The regression analysis demonstrated a significant inverse association between the GSM and the SUA/SCr ratio (β: -0.567; 95% CI -0.751 to -0.384 and p < 0.0001). Stepwise multivariate regression showed that the SUA/SCr ratio explained 30.3% of GSM variability (β: -0.600; 95% CI -0.777/-0.424, p < 0.0001, and semi-partial correlation 0.303). After a mean period of 3.5 ± 0.5 years, 48 patients were reevaluated according to the same baseline study protocol. The regression analysis demonstrated a still significant inverse association between the GSM and the SUA/SCr ratio (β: -0.462; 95% CI -0.745 to -0.178 and p = 0.002). Stepwise multivariate regression showed that the SUA/SCr ratio explained 28.0% of GSM variability (coefficient -0.584, 95% CI -0.848/-0.319, p < 0.0001, and semi-partial R² 0.280). In conclusion, this study demonstrates that SUA levels indexed for serum creatinine are associated with the echogenic features of carotid plaque vulnerability in elderly patients with atherosclerotic disease. These data could suggest an influential role for uric acid metabolism in carotid plaque biology.

Serum Uric Acid Predicts All-Cause and Cardiovascular Mortality Independently of Hypertriglyceridemia in Cardiometabolic Patients without Established CV Disease: A Sub-Analysis of the URic acid Right for heArt Health (URRAH) Study

High serum uric acid (SUA) and triglyceride (TG) levels might promote high-cardiovascular risk phenotypes across the cardiometabolic spectrum. However, SUA predictive power in the presence of normal and high TG levels has never been investigated. We included 8124 patients from the URic acid Right for heArt Health (URRAH) study cohort who were followed for over 20 years and had no established cardiovascular disease or uncontrolled metabolic disease. All-cause mortality (ACM) and cardiovascular mortality (CVM) were explored by the Kaplan-Meier estimator and Cox multivariable regression, adopting recently defined SUA cut-offs for ACM (≥4.7 mg/dL) and CVM (≥5.6 mg/dL). Exploratory analysis across cardiometabolic subgroups and a sensitivity analysis using SUA/serum creatinine were performed as validation. SUA predicted ACM (HR 1.25 [1.12-1.40], p < 0.001) and CVM (1.31 [1.11-1.74], p < 0.001) in the whole study population, and according to TG strata: ACM in normotriglyceridemia (HR 1.26 [1.12-1.43], p < 0.001) and hypertriglyceridemia (1.31 [1.02-1.68], p = 0.033), and CVM in normotriglyceridemia (HR 1.46 [1.23-1.73], p < 0.001) and hypertriglyceridemia (HR 1.31 [0.99-1.64], p = 0.060). Exploratory and sensitivity analyses confirmed our findings, suggesting a substantial role of SUA in normotriglyceridemia and hypertriglyceridemia. In conclusion, we report that SUA can predict ACM and CVM in cardiometabolic patients without established cardiovascular disease, independent of TG levels.

Hyperuricemia and kidney damage in patients with cardiovascular disease: A review

Many studies have been conducted confirming the effect of uric acid (UA) on kidney function. It is obvious that there is a relationship between the effect of UA not only on kidney function, but also on the cardiovascular system, increasing cardiovascular risk. The review article provides basic information about the pathogenesis, principles and features of prescribing therapy to patients with chronic kidney disease (CKD) and cardiovascular disease. A lot of data currently indicates that hyperuricemia, both with and without crystal deposition, is associated with high cardiovascular risk and decreased kidney function. A number of studies and meta-analyses indicate that urate-reducing therapy prevents and slows down the decline in kidney function in patients with CKD, many of whom suffer from cardiovascular diseases or at least have several risk factors. Despite the fact that currently the guidelines for the treatment of CKD do not include a recommendation for the start of urate-lowering therapy, a large amount of data has been accumulated on the potential benefits of such treatment even in the absence of a diagnosis of gout. The preferred group of drugs for this group of patients are xanthine oxidase inhibitors, and for patients with eGFR below 30 ml/min/1.73 m2, it seems that allopurinol currently has larger evidence base for the efficacy and safety of prescribing.

Serum uric acid / serum creatinine ratio as a predictor of cardiovascular events. Detection of prognostic cardiovascular cut-off values

OBJECTIVE

In the frame of the Uric Acid Right for Heart Health (URRAH) study, a nationwide multicenter study involving adult participants recruited on a regional community basis from all the territory of Italy under the patronage of the Working Group on Uric Acid and Cardiovascular Risk of the Italian Society of Hypertension, we searched for the cut-off values of the ratio between serum uric acid (SUA) and serum creatinine (sCr) able to predict cardiovascular (CV) events.

METHODS

Among 20 724 participants followed-up for 126 ± 64 months, after detecting cut-off by the receiver operating characteristic curves, we calculated by Cox models adjusted for confounders having CV events as dependent variable the hazard ratio (HR) of SUA/sCr > cut-off. We also verified if the role of cut-off varied with increasing SUA/sCr.

RESULTS

A plausible prognostic cut-off of SUA/sCr was found and was the same in the whole database, in men and in women (>5.35). The HR of SUA/sCr > cut-off was 1.159 (95% confidence interval [CI] 1.092-1.131, P < 0.03) in all, 1.161 (95% CI 1.021-1.335, P < 0.02) in men, and 1.444 (95% CI 1.012-1.113, P < 0.03) in women. In increasing quintiles of SUA/sCr the cut-offs were >3.08, >4.87, >5.35, >6.22 and >7.58, respectively. The HRs significantly increased from the 3rd to the 5th quintile (1.21, 95% CI 1.032-1.467, P = 0.018; 1.294, 95% CI 1.101-1.521, P = 0.002; and 1.642, 95% CI 1.405-1.919, P < 0.0001; respectively), that is, over 5.35, whereas the 2nd quintile was not significantly different from the 1st (reference).

CONCLUSION

Having SUA/sCr >5.35 is an independent CV risk indicator both in men and women. The cut-off is dynamic and significantly increases with increasing SUA/sCr.

Identification of a plausible serum uric acid cut-off value as prognostic marker of stroke: the Uric Acid Right for Heart Health (URRAH) study

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 combined (fatal and non-fatal) cerebrovascular (CBV) events in the whole database. The URic acid Right for heArt Health study is a nationwide, multicenter, observational cohort study involving data on subjects 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 120.7 ± 61.8 months. A total of 14,588 subjects were included in the analysis. A prognostic cut-off value of SUA able to discriminate combined CBV events (>4.79 mg/dL or >284.91 µmol/L) was identified by means of receiver operating characteristic curve in the whole database. Multivariate Cox regression analysis adjusted for confounders (age, sex, arterial hypertension, diabetes, chronic kidney disease, smoking habit, ethanol intake, body mass index, low-density lipoprotein cholesterol, and use of diuretics) identified an independent association between SUA and combined CBV events in the whole database (HR 1.249, 95% confidence interval, 1.041-1.497, p = 0.016). The results of the present study confirm that SUA is an independent risk marker for CBV events after adjusting for potential confounding variables, including arterial hypertension, and demonstrate that >4.79 mg/dL is a valid prognostic cut-off value.

Serum uric acid levels threshold for mortality in diabetic individuals: The URic acid Right for heArt Health (URRAH) project

BACKGROUND AND AIM

The URRAH (URic acid Right for heArt Health) Study has identified cut-off values of serum uric acid (SUA) predictive of total mortality at 4.7 mg/dl, and cardiovascular (CV) mortality at 5.6 mg/dl. Our aim was to validate these SUA thresholds in people with diabetes.

METHODS AND RESULTS

The URRAH subpopulation of people with diabetes was studied. All-cause and CV deaths were evaluated at the end of follow-up. A total of 2570 diabetic subjects were studied. During a median follow-up of 107 months, 744 deaths occurred. In the multivariate Cox regression analyses adjusted for several confounders, subjects with SUA ≥5.6 mg/dl had higher risk of total (HR: 1.23, 95%CI: 1.04-1.47) and CV mortality (HR:1.31, 95%CI:1.03-1.66), than those with SUA <5.6 mg/dl. Increased all-cause mortality risk was shown in participants with SUA ≥4.7 mg/dl vs SUA below 4.7 mg/dl, but not statistically significant after adjustment for all confounders.

CONCLUSIONS

SUA thresholds previously proposed by the URRAH study group are predictive of total and CV mortality also in people with diabetes. The threshold of 5.6 mg/dl can predict both total and CV mortality, and so is candidate to be a clinical cut-off for the definition of hyperuricemia in patients with diabetes.

The association of uric acid with mortality modifies at old age: data from the uric acid right for heart health (URRAH) study

OBJECTIVES

In older individuals, the role of serum uric acid (SUA) as risk factor for mortality is debated. This study investigated the association of SUA with all-cause and cardiovascular (CV) mortality in older adults participating in the large multicentre observational uric acid right for heart health (URRAH) study.

METHODS

Eight thousand URRAH participants aged 65+ were included in the analysis. The predictive role of SUA was assessed using Cox regression models stratified according to the cut-off age of 75. SUA was tested as continuous and categorical variable (age-specific quartiles). The prognostic threshold of SUA for mortality was analysed using receiver operating characteristic curves.

RESULTS

Among participants aged 65-74, multivariate Cox regression analysis adjusted for CV risk factors and comorbidities identified an independent association of SUA with both all-cause mortality (hazard ratio [HR] 1.169, 95% confidence interval [CI] 1.107-1.235) and CV mortality (HR 1.146, 95% CI 1.064-1.235). The cut-off value of 4.8 mg/dl discriminated mortality status. In participants aged 75+, we observed a J-shaped relationship of SUA with all-cause and CV mortality, with risk increasing at extreme SUA levels.

CONCLUSIONS

These results confirmed the predictive role of SUA for all-cause and CV mortality in older adults, while revealing considerable age-related differences. Mortality risk increased at higher SUA levels in participants aged 65-74, with a prognostic threshold of 4.8 mg/dl. The relationship between SUA and mortality was J-shaped in oldest participants. Large interventional studies are needed to clarify the benefits and possible risks of urate-lowering treatments in older adults.

The Urrah study

Uric acid has long been considered responsible for a single specific disease, namely gout. In recent years, novel knowledge has emerged linking serum uric acid with a variety of conditions and related risk factors, from hypertension, metabolic syndrome, and type 2 diabetes, to fatal/nonfatal cardiovascular diseases and all-cause death, with the underlying mechanisms involving disrupted neurohormonal and metabolic signaling as well as oxidative stress and inflammation. Importantly, the cut-off value of serum uric acid predicting the risk of incident events is within the range of normality and below the threshold for increased risk of gout. A large contribution to the advancement in knowledge in the cardiovascular implications of uric acid derives from the Italian study URic acid Right for heArt Health (URRAH). This review summarizes the mechanisms linking uric acid with cardiovascular risk and the major findings of the URRAH study. The need for a reappraisal of the definition of range of normality for uric acid is discussed.

Association of uric acid with kidney function and albuminuria: the Uric Acid Right for heArt Health (URRAH) Project

BACKGROUND

Hyperuricemia is commonly observed in patients with chronic kidney disease (CKD). However, a better understanding of the relationship among uric acid (UA) values, glomerular filtration rate (GFR) and albuminuria may shed light on the mechanisms underlying the excess of cardiovascular mortality associated with both chronic kidney disease and hyperuricemia and lead to better risk stratification. Our main goal was to study the relationships between serum uric acid and kidney disease measures (namely estimated GFR [eGFR] and albuminuria) in a large cohort of individuals at cardiovascular risk from the URic acid Right for heArt Health (URRAH) Project database.

METHODS

Clinical data of 26,971 individuals were analyzed. Factors associated with the presence of hyperuricemia defined on the basis of previously determined URRAH cutoffs for cardiovascular and all-cause mortality were evaluated through multivariate analysis. Chronic kidney disease was defined as eGFR < 60 ml/min per 1.73 m² and/or abnormal urinary albumin excretion diagnosed as: (i) microalbuminuria if urinary albumin concentration was > 30 and ≤ 300 mg/L, or if urinary albumin-to-creatinine ratio (ACR) was > 3.4 mg/mmol and ≤ 34 mg/mmol; (ii) macroalbuminuria if urinary albumin concentration was > 300 mg/L, or if ACR was > 34 mg/mmol.

RESULTS

Mean age was 58 ± 15 years (51% males, 62% with hypertension and 12% with diabetes), mean eGFR was 81 ml/min per 1.73m2²with a prevalence of eGFR < 60 and micro- or macroalbuminuria of 16, 15 and 4%, respectively. Serum uric acid showed a trend towards higher values along with decreasing renal function. Both the prevalence of gout and the frequency of allopurinol use increased significantly with the reduction of eGFR and the increase in albuminuria. Hyperuricemia was independently related to male gender, eGFR strata, and signs of insulin resistance such as body mass index (BMI) and triglycerides.

CONCLUSIONS

The lower the eGFR the higher the prevalence of hyperuricemia and gout. In subjects with eGFR < 60 ml/min the occurrence of hyperuricemia is about 10 times higher than in those with eGFR > 90 ml/min. The percentage of individuals treated with allopurinol was below 2% when GFR was above 60 ml/min, it increased to 20% in the presence of CKD 3b and rose further to 35% in individuals with macroalbuminuria.

The importance of including uric acid in the definition of metabolic syndrome when assessing the mortality risk

Introduction

Serum uric acid (SUA) has been depicted as a contributory causal factor in metabolic syndrome (MS), which in turn, portends unfavourable prognosis.

Aim

We assessed the prognostic role of SUA in patients with and without MS.

Methods

We used data from the multicentre Uric Acid Right for Heart Health study and considered cardiovascular mortality (CVM) as death due to fatal myocardial infarction, stroke, sudden cardiac death, or heart failure.

Results

A total of 9589 subjects (median age 58.5 years, 45% males) were included in the analysis, and 5100 (53%) patients had a final diagnosis of MS. After a median follow-up of 142 months, we observed 558 events. Using a previously validated cardiovascular SUA cut-off to predict CVM (> 5.1 mg/dL in women and 5.6 mg/dL in men), elevated SUA levels were significantly associated to a worse outcome in patients with and without MS (all p < 0.0001) and provided a significant net reclassification improvement of 7.1% over the diagnosis of MS for CVM (p = 0.004). Cox regression analyses identified an independent association between SUA and CVM (Hazard Ratio: 1.79 [95% CI, 1.15–2.79]; p < 0.0001) after the adjustment for MS, its single components and renal function. Three specific combinations of the MS components were associated with higher CVM when increasing SUA levels were reported, and systemic hypertension was the only individual component ever-present (all p < 0.0001).

Conclusion

Increasing SUA levels are associated with a higher CVM risk irrespective of the presence of MS: a cardiovascular SUA threshold may improve risk stratification.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s00392-021-01815-0.

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

Supplemental Digital Content is available in the text

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.

Serum electrolyte/metabolite abnormalities among patients with acute myocardial infarction: comparison between patients with and without diabetes mellitus

Background: Diabetes mellitus (DM) in a setting of acute myocardial infarction (AMI) is associated with significant metabolic changes and worse outcomes.Objective: To evaluate the prevalence and the prognostic significance of electrolyte/metabolite disturbances among AMI patients with vs. without DM.Methods: Patients admitted to a tertiary medical center with AMI throughout 2002-2012 were screened. Exclusion criteria were: dialysis, mechanical ventilation, and in-hospital coronary artery bypass graft (CABG) surgery. All the results of the following analyses were obtained: Glucose, Uric Acid, (UA) Calcium, Magnesium, Albumin, Potassium, and Sodium. The primary outcome was in-hospital all-cause mortality.Results: A total of 14,364 AMI patient admissions was evaluated, mean age 68.1 ± 14.4 years, 65.5% males, and 41.2% with DM. Following an adjustment to potential confounders, DM patients had increased risk for significant hyperglycemia, hyperuricemia, hypercalcemia, hypomagnesemia, hyperkalemia, and hyponatremia as well as significantly decreased risk for hypoglycemia, hypermagnesemia, and hypokalemia compared with nondiabetics. Overall, 681 (4.7%) patients died throughout the index admission. Deceased had an increased incidence of electrolyte/metabolite abnormalities versus hospital survivors. The prognostic significance of the different categories of the investigated variables is very similar among diabetics and nondiabetics, except increased and decreased uric acid levels [<4.5 (men); <4.0 (women) and ≥9.0 (men); ≥9.4 (women)] which are associated with worse outcomes among diabetics while hyperglycemia (Glucose ≥213 mg/dL) and increased Potassium levels (Potassium ≥4.4mEq/L) which comprise significantly worse prognosis among nondiabetics.Conclusions: Patients with DM admitted with AMI are at greater risk for electrolyte/metabolite abnormalities which are associated with increased risk for in-hospital mortality. The latter association is similar among patients with and without DM except for hyperglycemia and increased potassium levels (stronger among nondiabetics).

Relationships between diuretic-related hyperuricemia and cardiovascular events: data from the URic acid Right for heArt Health study

OBJECTIVE

Although the relationship between hyperuricemia and cardiovascular events has been extensively examined, data on the role of diuretic-related hyperuricemia are still scanty. The present study was designed to collect information on the relationship between diuretic-related hyperuricemia and cardiovascular events.

METHODS

The URic acid Right for heArt Health (URRAH) study is a nationwide, multicentre, observational cohort study involving data on individuals recruited from all the Italy territory under the patronage of the Italian Society of Hypertension with an average follow-up period of 122.3 ± 66.9 months. Patients were classified into four groups according to the diuretic use (yes vs. no) and serum uric acid (SUA) levels (higher vs. lower than the median value of 4.8 mg/dl). All-cause death, cardiovascular deaths and first cardiovascular event were considered as outcomes.

RESULTS

Seventeen thousand, seven hundred and forty-seven individuals were included in the analysis. Mean age was 57.1 ± 15.2 years, men were 45.3% and SBP and DBP amounted to 144.1 ± 24.6 and 85.2 ± 13.2 mmHg. 17.2% of individuals take diuretics of whom 58% had SUA higher than median value. Patients with hyperuricemia without diuretic use served as reference group. In multivariate adjusted analysis (sex, age, SBP, BMI, glucose, total cholesterol, and glomerular filtration rate) individuals with hyperuricemia and diuretic use exhibit a similar risk for the three outcomes as compared with the reference group.

CONCLUSION

Our study showed that diuretic-related hyperuricemia carry a similar risk of cardiovascular events and all-cause mortality when compared with individuals that present hyperuricemia in absence of diuretic therapy.

Management of Hyperuricemia in Patients with Chronic Kidney Disease: a Focus on Renal Protection

PURPOSE OF REVIEW

In chronic kidney disease (CKD), plasma uric acid levels are increased because of the decrease in glomerular filtration rate. However, in addition to CKD, hyperuricemia is frequently associated with a number of other conditions such as hypertension, type 2 diabetes, obesity, and heart failure, overweight, and cardiovascular disease.

RECENT FINDINGS

It is now becoming increasingly clear that, in many clinical conditions, elevated levels of uric acid have a much greater role beyond just causing gout. The present review will summarize current knowledge on the relation between hyperuricemia, CKD, and existing comorbidities, as well as the mechanisms of uric acid-related renal damage. In addition, the role and evidence for urate-lowering therapy in prevention and cardiovascular protection in CKD patients is discussed with a focus on allopurinol and febuxostat. To date, several clinical studies have provided evidence that urate-lowering therapy may help to prevent and delay the decline of renal function in patients with CKD. Use of a xanthine oxidase inhibitor should be considered in patients who are at high renal risk and/or with declining renal function in the presence of hyperuricemia with and without deposition, although additional studies are warranted to define treatment targets. Notwithstanding, the possibility to delay deterioration of renal function in patients with CKD merits consideration.

Food Consumption is Associated with Hyperuricemia in Boys

INTRODUCTION

Hyperuricemia is related to health issues among children and adolescents, once the uric acid concentration is associated with metabolic syndrome, hypertension, insulin resistance, obesity, and dyslipidemia. However, few studies are addressing uric acid levels and food uptake in this age group.

AIM

To verify the association between food consumption and uric acid in children and adolescents.

METHODS

This is a cross-sectional study developed with 2335 children and adolescents of both genders aged 6-17 years old. Blood collection was performed after 12 h of fasting. Uric acid values were classified according to tertiles, in which the highest tertile was considered as hyperuricemia. Food consumption was evaluated by weekly consumption frequency questionnaire. Pearson correlation and logistic binary regressions were used for statistical analysis. Models were adjusted for age, systolic blood pressure, body mass index (BMI), and skin color/ethnicity.

RESULTS

It was found an association between red meat consumption and hyperuricemia only in boys in the crude model (OR = 1.56; 95% CI 1.12; 2.18). Also, there was an association between pasta (OR = 1.52; 95% CI 1.11; 2.10) with hyperuricemia in boys, when adjusted age, systolic blood pressure, BMI, and skin color/ethnicity.

CONCLUSION

The knowledge of food patterns which are predisposing factors for the increase in serum uric acid levels is important for the implementation of strategies and public health policies for health promotion among children and adolescents.

Serum uric acid, predicts heart failure in a large Italian cohort: search for a cut-off value the URic acid Right for heArt Health study

OBJECTIVE

To assess the prognostic cut-off values of serum uric acid (SUA) in predicting fatal and morbid heart failure in a large Italian cohort in the frame of the Working Group on Uric Acid and Cardiovascular Risk of the Italian Society of Hypertension.

METHODS

The URic acid Right for heArt Health (URRAH) study is a nationwide, multicentre, cohort study involving data on individuals aged 18-95 years, recruited on a community basis from all regions of Italy under the patronage of the Italian Society of Hypertension with a mean follow-up period of 128 ± 65 months. Incident heart failure was defined on the basis of International Classification of Diseases Tenth Revision codes and double-checked with general practitioners and hospital files. Multivariate Cox regression models having fatal and morbid heart failure as dependent variables, adjusted for sex, age, SBP, diabetes, estimated glomerular filtration rate, smoking habit, ethanol intake, BMI, haematocrit, LDL cholesterol, previous diagnosis of heart failure and use of diuretics as possible confounders, were used to search for an association between SUA as a continuous variable and heart failure. By means of receiver operating characteristic curves, two prognostic cut-off values (one for all heart failure and one for fatal heart failure) were identified as able to discriminate between individuals doomed to develop the event. These cut-off values were used as independent predictors to divide individuals according to prognostic cut-off values in a multivariate Cox models, adjusted for confounders.

RESULTS

A total of 21 386 individuals were included in the analysis. In Cox analyses, SUA as a continuous variable was a significant predictor of all [hazard ratio 1.29 (1.23-1.359), P < 0.0001] and fatal [hazard ratio 1.268 (1.121-1.35), P < 0.0001] incident heart failure. Cut-off values of SUA able to discriminate all and fatal heart failure status were identified by mean of receiver operating characteristic curves in the whole database: SUA more than 5.34 mg/dl (confidence interval 4.37-5.6, sensitivity 52.32, specificity 63.96, P < 0.0001) was the univariate prognostic cut-off value for all heart failure, whereas SUA more than 4.89 mg/dl (confidence interval 4.78-5.78, sensitivity 68.29, specificity 49.11, P < 0.0001) for fatal heart failure. The cut-off for all heart failure and the cut-off value for fatal heart failure were accepted as independent predictors in the Cox analysis models, the hazard ratios being 1.645 (1.284-2.109, P < 0.0001) for all heart failure and 1.645 (1.284-2.109, P < 0.0001) for fatal heart failure, respectively.

CONCLUSION

The results of the current study confirm that SUA is an independent risk factor for all heart failure and fatal heart failure, after adjusting for potential confounding variables and demonstrate that a prognostic cut-off value can be identified for all heart failure (>5.34 mg/dl) and for fatal heart failure (>4.89 mg/dl).

Circulating leptin is associated with serum uric acid level and its tubular reabsorption in a sample of adult middle-aged men

PURPOSE

Leptin is associated with cardiovascular risk factors (e.g. hypertension, insulin resistance, kidney disease and excess body weight). Experimental studies showed that leptin might affect serum uric acid, by modulation of the uric acid excretion. However, there are few observational data on the relationship between leptin and uric acid in the general population. Therefore, the aim of the present study was to evaluate the relationship between leptin and uric acid and its excretion in a large middle-aged male general population.

METHODS

A sample of 930 adult male individuals (mean age: 52 years) without therapy for high uric acid was included in the analysis (the Olivetti Heart Study).

RESULTS

Uric acid was significantly and positively associated with blood pressure, BMI, waist circumference, insulin resistance, C-reactive protein and leptin (p < 0.01), while inversely with renal function (p = 0.01). The multivariate analysis confirmed the association between leptin and uric acid after adjustment for potential confounders (p < 0.01). After division for adiposity, this trend was confirmed separately for normal weight and excess body weight participants. Moreover, leptin was inversely associated with excretion of uric acid (p < 0.01), also in multivariate analysis (p = 0.03).

CONCLUSION

The results of this study indicate a positive association between circulating leptin levels and uric acid, independently of potential confounders, both in normal and excess body weight men. Furthermore, an inverse association between leptin and uric acid excretion was detected.

Hyperuricemia and Risk of Cardiovascular Outcomes: The Experience of the URRAH (Uric Acid Right for Heart Health) Project

The latest European Guidelines of Arterial Hypertension have officially introduced uric acid evaluation among the cardiovascular risk factors that should be evaluated in order to stratify patient's risk. In fact, it has been extensively evaluated and demonstrated to be an independent predictor not only of all-cause and cardiovascular mortality, but also of myocardial infraction, stroke and heart failure. Despite the large number of studies on this topic, an important open question that still need to be answered is the identification of a cardiovascular uric acid cut-off value. The actual hyperuricemia cut-off (> 6 mg/dL in women and 7 mg/dL in men) is principally based on the saturation point of uric acid but previous evidence suggests that the negative impact of cardiovascular system could occur also at lower levels. In this context, the Working Group on uric acid and CV risk of the Italian Society of Hypertension has designed the Uric acid Right for heArt Health project. The primary objective of this project is to define the level of uricemia above which the independent risk of CV disease may increase in a significantly manner. In this review we will summarize the first results obtained and describe the further planned analysis.

Identification of the Uric Acid Thresholds Predicting an Increased Total and Cardiovascular Mortality Over 20 Years

Serum uric acid (SUA) levels discriminating across the different strata of cardiovascular risk is still unknown. By utilizing a large population-based database, we assessed the threshold of SUA that increases the risk of total mortality and cardiovascular mortality (CVM). The URRAH study (Uric Acid Right for Heart Health) is a multicentre retrospective, observational study, which collected data from several large population-based longitudinal studies in Italy and subjects recruited in the hypertension clinics of the Italian Society of Hypertension. Total mortality was defined as mortality for any cause, CVM as death due to fatal myocardial infarction, stroke, sudden cardiac death, or heart failure. A total of 22 714 subjects were included in the analysis. Multivariate Cox regression analyses identified an independent association between SUA and total mortality (hazard ratio, 1.53 [95% CI, 1.21-1.93]) or CVM (hazard ratio, 2.08 [95% CI, 1.146-2.97]; P<0.001). Cutoff values of SUA able to discriminate total mortality (4.7 mg/dL [95% CI, 4.3-5.1 mg/dL]) and CVM status (5.6 mg/dL [95% CI, 4.99-6.21 mg/dL]) were identified. The information on SUA levels provided a significant net reclassification improvement of 0.26 and of 0.27 over the Heart Score risk chart for total mortality and CVM, respectively (P<0.001). Sex-specific cutoff values for total mortality and CVM were also identified and validated. In conclusion, SUA levels increasing the risk of total mortality and CVM are significantly lower than those used for the definition of hyperuricemia in clinical practice. Our data provide evidence of a cardiovascular SUA threshold that might contribute in clinical practice to improve identification of patients at higher risk of CVM.

Pulse wave velocity progression over a medium-term follow-up in hypertensives: Focus on uric acid

The role of uric acid (UA) on the arterial stiffness progression has been evaluated only in three studies. Our aim was to evaluate its role as a possible determinant of the pulse wave velocity (PWV) progression over a 3.7 ± 0.5 years follow-up period in hypertensive patients. Specific sex analysis was done due to the well-known sex interaction with UA levels. We enrolled 422 consecutive hypertensive outpatients. At baseline anamnestic, blood pressure (BP) and laboratory data as well as PWV were assessed. PWV was performed again at follow-up examination. Hyperuricemia was defined as a UA > 6 mg/dL for women and > 7 mg/dL for men. Baseline age was 53.2 ± 13 years, 58% were males, systolic and diastolic BP (SBP/DBP) 141.7 ± 17.7/86.8 ± 10.8 mm Hg, UA 5.2 ± 1.4 mg/dL, and PWV 8.5 ± 1.9 m/s. At follow-up, despite better BP values (-8.5 ± 24.6 for SBP and -7.5 ± 15.4 for DBP), PWV increases to 9.1 ± 2.3 m/s (P < 0.001) with mean ΔPWV of+ 0.5 ± 2.2 m/s. A total of 61 patients were hyperuricemic (14.4%), and they present higher PWV baseline (9.0 ± 2.5 vs 8.5 ± 1.8 m/s, P = 0.03) without significant differences in ΔPWV. Hyperuricemic female (6.2%, 11 patients) presents higher baseline PWV without significant differences in ΔPWV. No differences were found in arterial stiffness in hyperuricemic males (20.4%, 50 patients). UA showed association with baseline and ΔPWV in the whole population but it loses statistical significance at the linear regression model. Same figures were also for sex analysis. Our findings provide evidence that baseline UA levels are not determinants of PWV progression over a median follow-up of 3.8 years' in hypertensive patients.

Hyperuricemia is associated with acute kidney injury and all-cause mortality in hospitalized patients

AIM

Hyperuricemia is a risk factor for high morbidity and mortality in several diseases. However, the relationship between uric acid (UA) and the risk of acute kidney injury (AKI) and mortality remain unresolved in hospitalized patients.

METHODS

Data from 18 444 hospitalized patients were retrospectively reviewed. The odds ratio (OR) for AKI and the hazard ratio (HR) for all-cause mortality were calculated based on the UA quartiles after adjustment for multiple variables. All analyses were performed after stratification by sex.

RESULTS

The fourth quartile group (male, UA > 6.7 mg/dL; female, UA > 5.4 mg/dL) showed a higher risk of AKI compared with the first quartile group (male, UA < 4.5 mg/dL; female, UA < 3.6 mg/dL), with the following OR: 3.2 (2.55-4.10) in males (P < 0.001); and 3.1 (2.40-4.19) in females (P < 0.001). There were more patients who did not recover from AKI in the fourth quartile compared with the first quartile, with the following OR: 2.0 (1.32-3.04) in males (P = 0.001) and 2.4 (1.43-3.96) in females (P = 0.001). The fourth quartile group had a higher risk of all-cause mortality compared with the first quartile group, with the following HR: 1.4 (1.20-1.58) in males (P < 0.001) and 1.2 (1.03-1.46) in females (P = 0.019). The in-hospital mortality risk was also higher in the fourth quartile compared with the first quartile, which was significant only in males (OR, 2.1 (1.33-3.31) (P = 0.002)).

CONCLUSION

Hyperuricemia increases the risks of AKI and all-cause mortality in hospitalized patients.

Reference interval and upper decission limit for serum uric acid – an evidence-based approach on Romanian population using an a posteriori method

Introduction. There is accumulating evidence that high normal serum uric acid (SUA) levels of 6-7 mg/dL are associated with cardiovascular morbidity and metabolic syndrome (MetS), hence the need to redefine its upper limit of normal (ULN). We aimed to derive ULN based on statistics and evidence in a representative sample of the population and to observe its relation to MetS components.

Methods. All SUA measurements form a university rheumatology hospital were extracted between January 5th 2010 and March 21st 2018. SUA levels were measured by a single biochemist a unique type of commercially available kit. Follow-up measurements, patients with diagnoses influencing SUA levels and outlying measurements were excluded. ULNs were studied using least square analysis.

Results. Of the 22503 SUA measurements in the database, only 3318 came from normal individuals: 33.3% men (n=1105), 66.7% women (n = 2213). Least square analysis revealed the following SUA reference intervals (RI): 3.43-6.19 mg/dL for the combined sample; 4.44-7.01 mg/dL for men, 3.28-5.56 mg/dL for women. The values corresponding to the 66th percentile of each group presented lower ULNs: 5.36 mg/dL for all, 6.10 mg/dL for men, 4.90 mg/dL for women. The prevalence of hyperuricemia increased from 13.8% (manufacturer’s gender-specific ULN) to 19.9% (derived ULN). Mean SUA levels significantly increased with the number of MetS components.

Conclusion. We recommend that hyperuricemia should be defined using a statistical approach of ULN selection corresponding to the genderand population-specific 66th percentile of data range.