Significance of high-normal serum uric acid level as a risk factor for arterial stiffness in healthy Korean men

High-normal serum uric acid predicts macrovascular events in patients with type 2 diabetes mellitus without hyperuricemia based on a 10-year cohort

BACKGROUND AND AIMS

The upper limits of normal serum uric acid (SUA) or the lower limits of hyperuricemia were frequently set at 420 or 360 μmol/L (7.0 or 6.0 mg/dL). We aimed to explore the association between high-normal SUA (360 ≤ SUA≤420 μmol/L) and incidence of macrovascular and renal events based on a 10-year cohort with type 2 diabetes mellitus (T2DM) to explore which cut-off was more appropriate.

METHODS AND RESULTS

A total of 2988 patients with T2DM without hyperuricemia (SUA≤420 μmol/L) were included and followed up. Cox proportional hazards models and restricted cubic spline regression were used to evaluate the relationship between baseline SUA (as continuous and categorical variable) and macrovascular and renal events. Patients were grouped as low-normal (SUA<360 μmol/L) and high-normal groups based on baseline SUA, and the latter group had higher incidence of macrovascular events. Multivariate Cox regression analysis indicated that baseline levels of SUA were significantly associated with cardiovascular (HR = 1.385, 95%CI:1.190-1.613, P < 0.001) and peripheral vascular events (HR = 1.266, 95%CI:1.018-1.574, P = 0.034), and the linear association existed. Moreover, fully adjusted multivariable Cox analyses indicated high-normal SUA increased the risks of cardiovascular (HR = 1.835, 95%CI:1.319-2.554, P < 0.001) and peripheral vascular events (HR = 1.661, 95%CI:1.000-2.760, P = 0.050) compared to low-normal SUA.

CONCLUSIONS

Baseline SUA levels were positively associated with cardiovascular and peripheral vascular events, and high-normal SUA increased the risks of these events in patients with T2DM even without hyperuricemia. A threshold value for SUA of 360 μmol/L should be more appropriate in terms of predicting macrovascular events risks compared to the value of 420 μmol/L.

Sex-specific association of serum uric acid trajectories with risk of incident retinal arteriosclerosis in Chinese population: A population-based longitudinal study

Background

The impact of serum uric acid (SUA) trajectories on the development of retinal arteriosclerosis is uncertain. The purpose of this study was to identify adult SUA trajectories by sex and determine their association with risk of retinal arteriosclerosis.

Methods

In this longitudinal study, 4,324 participants who were aged between 18 and 60 years without retinal arteriosclerosis at or before baseline (from January 1, 2010, through December 31, 2010) were included. Group-based trajectory modeling was used to identify SUA trajectories during the exposure period (from January 1, 2006, through December 31, 2010). Cox proportional-hazards models were applied to evaluate the associations between SUA trajectories and the risk of incident retinal arteriosclerosis during the outcome period (from January 1, 2011, through December 31, 2019).

Results

4 distinct SUA trajectories were identified in both women and men: low, moderate, moderate-high, and high. During a median follow-up of 9.54 years (IQR 9.53-9.56), 97 women and 295 men had developed retinal arteriosclerosis. In the fully adjusted model, a significant association between the moderate-high SUA trajectory group and incidence of retinal arteriosclerosis was observed only in men (HR: 1.76, 95% CI: 1.17-2.65) compared with the low trajectory group, but not in women (HR: 0.77, 95% CI: 0.39-1.52). Also, the high SUA trajectory group had the highest risk with an adjusted HR of 1.81 (95% CI, 1.04-3.17) in men. However, they did not exhibit a substantially increased risk in women.

Conclusion

Higher SUA trajectory groups were significantly associated with an increased risk of incident retinal arteriosclerosis in men but not in women.

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.

Hyperuricemia prevalence in healthy subjects and its relationship with cardiovascular target organ damage

BACKGROUND AND AIM

Heterogeneous results have been obtained in the relationship between Uric Acid (UA) and Target Organ Damage (TOD). In the present study we sought to assess the prevalence of hyperuricemia in healthy subjects as well as the role of UA in determining TOD. We evaluated vascular, cardiac and renal TODs in the whole population as well as sub-grouped by gender.

METHODS AND RESULTS

As many as 379 blood donors participated at the present analysis. TOD was evaluated as Pulse Wave Velocity (PWV), Left Ventricular Mass Index (LVMI) and carotid Intima-Media Thickness (IMT). Hyperuricemia was defined with the classic cut-off (>7.0 in men and >6.0 mg/dL in women) but also with a most recently defined one (5.6 mg/dL for both sex). Hyperuricemia was present in 6.3% of the whole population (7.3% males, 2.8% females) considering the classic cut-off, while, with the recently identified one, it was present in 28.2% of the whole population (37.3% males, 4.7% females). Despite all the evaluated TODs significantly correlated with UA, linear multivariate regression analysis showed that none of them, except for GFR, displayed UA as a significant covariate. Similar figures were found also when both correlation and linear regression analyses were repeated in the two genders separately.

CONCLUSIONS

Hyperuricemia is an important problem also in healthy subjects and its prevalence could further increase if lower cut-off will be used. In this specific population UA is significantly associated with renal impairment while this was not the case for cardiac and vascular damage.

High serum uric acid is associated with increased arterial stiffness in hypertension

Serum uric acid level has been found to be associated with cerebrovascular diseases. However, whether serum uric acid level is a risk factor for arterial stiffness in the hypertension population is unclear. This study was designed to determine the relationship between serum uric acid level and arterial stiffness in the hypertension population. A total of 10450 participants were evaluated for the risk of arterial stiffness. Brachial-ankle pulse wave velocity (baPWV) was assessed, and high baPWV was determined as the highest quartile of baPWV values in a sex-specific manner. We evaluated the association between serum uric acid level and baPWV through multivariate-adjusted linear and logistic regression analyses. There was a significant difference on high baPWV between patients with quartiles of serum uric acid level in females and males (p<0.01), respectively. The odds ratios (95% CI) of the highest baPWV quartile across the sex-specific serum uric acid level were 1.0, 1.71 (1.35, 2.17), 1.75 (1.38, 2.23), and 1.95 (1.51, 2.51) in female, and 1.0, 1.33 (1.09, 1.64), 1.36 (1.11, 1.67), and 1.67 (1.36, 2.04) in male after adjusting for potential confounders. In conclusion, serum uric acid level could be considered as an important risk factor for arterial stiffness in Chinese hypertension population.

Gender-Specific Association between Serum Uric Acid and Incident Fundus Arteriosclerosis in Chinese Population: A Retrospective Cross-Sectional Study

Elevated levels of serum uric acid (SUA) were considered to be risk factors for cardiovascular disease, it has been found to be associated with increased arteriosclerosis. The aim of this study was to explore the gender specific relationship between SUA and fundus arteriosclerosis in a healthy population. In a retrospective cross-sectional study, 23474 individuals without diabetes and hypertension were included in the present study. SUA levels were cut to four groups as Q1 to Q4, according to the quartiles. The odds ratio and 95% confidence interval of different SUA levels were estimated by a binomial logistic regression model. A restrictive cubic spline method was used to estimate the dose-response relationship between SUA and fundus arteriosclerosis. Subgroup analysis was performed to find the gender-specific association between SUA and incident fundus arteriosclerosis. In males, after adjusting for confounding factors, the highest SUA level was significantly associated with the risk of incident fundus arteriosclerosis. The OR with 95%CI for Q4 was 1.44(1.18, 1.76), Q1 as a reference. Specially, for females, SUA level was not associated with the incidence of fundus arteriosclerosis. In conclusion, elevated levels of SUA were associated with the incidence of fundus arteriosclerosis in males, but not in females.

Association between uric acid and pulse wave velocity in hypertensive patients and in the general population: a systematic review and meta-analysis

Purpose: The association between serum uric acid (SUA) and pulse wave velocity (PWV), has been extensively evaluated but with some discrepancies in results. A further limitation refers to the fact that only few data were analyzed taking into account the possible effects of gender. The purpose of this study was to estimate the association between SUA and arterial stiffness in general population and hypertensive patients, as a whole population and as divided by gender, by pooling results from existing studies.Materials and methods: Carotid-femoral and brachial-ankle PWV (cf- and ba-PWV) have been analyzed separately and subgroup analyses by gender are reported. Among 692 potentially relevant works, 24 articles were analyzed.Results: Seven studies referred to cf-PWV in the general population with an overall positive association at adjusted analysis for both males and females (beta regression coefficient (ß): 0.07; 95%CI: 0.03; 0.11 and ß: 0.06; 95%CI: 0.03; 0.09, respectively). Twelve studies referred to ba-PWV in the general population with the finding of a positive association at adjusted analysis for females (ß: 0.04; 95% confidence interval (CI): 0.01;0.07), but not for males (ß: 0.13; 95%CI: -0.09; 0.34). In hypertensive patients only four studies evaluated cf-PWV and one ba-PWV with only one study (with cf-PWV) finding positive association.Conclusion: The association between SUA and cf-PWV resulted significant in general population in both males and females while it was only significant for female regarding ba-PWV. Furthermore, the few available studies found no significant relationship between SUA and both cf- and ba-PWV in hypertensive subjects.

Uric Acid and Arterial Stiffness

Hyperuricemia is usually associated with hypertension, diabetes mellitus, metabolic syndrome and chronic kidney disease. Accumulating data from epidemiological studies indicate an association of increased uric acid (UA) with cardiovascular diseases. Possible pathogenic mechanisms include enhancement of oxidative stress and systemic inflammation caused by hyperuricemia. Arterial stiffness may be one of the possible pathways between hyperuricemia and cardiovascular disease, but a clear relationship between increased UA and vascular alterations has not been confirmed. The review summarizes the epidemiological studies investigating the relationship between UA and arterial stiffness and highlights the results of interventional studies evaluating arterial stiffness parameters in patients treated with UA-lowering drugs.

Uric acid association with pulsatile and steady components of central and peripheral blood pressures

OBJECTIVE

Whether the cardiovascular risk attributed to elevated uric acid levels may be explained by changes in central and peripheral pulsatile and/or steady blood pressure (BP) components remains controversial.

METHODS

In a cross-sectional analysis of normotensive and untreated hypertensive participants of the CARTaGENE populational cohort, we examined the relationship between uric acid, and both pulsatile and steady components of peripheral and central BP, using sex-stratified linear regressions.

RESULTS

Of the 20 004 participants, 10 161 individuals without antihypertensive or uric acid-lowering drugs had valid pulse wave analysis and serum uric acid levels. In multivariate analysis, pulsatile components of BP were not associated with uric acid levels, whereas steady components [mean BP (MBP), peripheral and central DBP] were all associated with higher levels of uric acid levels in women and men (all P < 0.001). Furthermore, there was a gradual increase of central SBP (cSBP), DBP and MBP from the lowest to the highest quintiles of uric acid levels but not for MBP-adjusted cSBP. Peripheral and cSBP, which are aggregate measures of pulsatile and steady BP, were also associated with uric acid levels in women (β = 0.063 and 0.072, respectively, both P < 0.001) and men (β = 0.043 and 0.051, both P ≤ 0.003). After further adjustments for MBP to account for the concomitant increase in steady component of BP, SBPs were no longer associated with uric acid levels.

CONCLUSION

Serum uric acid levels appear to be associated with both central and peripheral steady but not pulsatile BP, regardless of sex.

The Relationships of the Fractional Excretion of Uric Acid with Brachial-Ankle Pulse Wave Velocity and Ankle Brachial Index in Chinese Young Adults

BACKGROUND/AIMS

Elevated serum uric acid (UA) was intimately correlated with vascular stiffness and abnormal ankle brachial index (ABI) in various populations. These correlations lost significance after adjustment for estimated glomerular filtration rate (eGFR), indicating that the association of UA and brachial-ankle pulse wave velocity (baPWV) or ABI might be driven by kidney function. UA is predominantly eliminated through the kidneys, and metabolic disorders can influence the clearance of UA. In this study, we aimed to explore the putative correlation between FEUA and baPWV or ABI to determine to what extent the associations with UA were affected by renal function.

METHODS

This cross-sectional study enrolled 2351 participants, who underwent general health screening in Hanzhong people's hospital from March to June of 2017. BaPWV and ABI were measured using a volume-plethysmographic apparatus (BP-203RPEII; Nihon Colin, Tokyo, Japan). FEUA was divided into quartiles: Q1:FEUA≤3.07; Q2: 3.07<FEUA≤5.32; Q3: 5.32<FEUA≤9.19; and Q4: FEUA> 9.19.

RESULTS

Lower FEUA predicted a higher prevalence of high baPWV and low ABI (p for trend <0.001). The respective ORs for high baPWV from the first to the third quartiles of FEUA were 1.777(1.323, 2.387); 1.561(1.158, 2.104); and 1.680 (1.250, 2.259). The prevalence of low ABI was greatly elevated with the decrement of FEUA [ORs for the first to third FEUA quartiles were 6.977(2.062, 23.610); 5.123(1.475, 17.790); and 2.685(0.709, 10.171), respectively]. The association of FEUA and ABI was independent of related confounding factors. However, the association between FEUA and baPWV was greatly influenced by corresponding confounders, especially gender. The efficacy of FEUA in the prediction of low ABI was stronger than that of serum UA. However, serum UA was more powerful in the prediction of high baPWV.

CONCLUSION

Kidney function exerted a profound influence on the relationship between UA and baPWV or ABI, revealing complex interactions among cardiovascular risk factors.

Uric Acid Level Has a J-Shaped Association with Arterial Stiffness in Korean Postmenopausal Women

Background

Uric acid has been reported to function both as an oxidant or antioxidant depending on the context. A previous study in the Korean population reported a positive linear association between serum uric acid level and arterial stiffness in men, but little is known about how serum uric acid level is related to the risk of increased arterial stiffness in Korean postmenopausal women.

Methods

We performed a cross-sectional study of 293 subjects who participated in a health examination program run by the health promotion center of Gangnam Severance Hospital between October 2007 and July 2010. High brachial-ankle pulse wave velocity was defined as a brachial-ankle pulse wave velocity of more than 1,450 cm/s. The odds ratios (ORs) for high brachial-ankle pulse wave velocity were calculated using multivariate logistic regression analysis across uric acid quartiles after adjusting for other indicators of cardiovascular risk.

Results

The 293 postmenopausal women were divided into quartiles according to uric acid level. The mean brachial-ankle pulse wave velocity values of each quartile were as follows: Q1, 1,474 cm/s; Q2, 1,375 cm/s; Q3, 1,422 cm/s; Q4, 1,528 cm/s. The second quartile was designated as the control group based on mean brachial-ankle pulse wave velocity value. Multivariate adjusted ORs (95% confidence intervals) for brachial-ankle pulse wave velocity across the uric acid quartiles were 2.642 (Q1, 1.095–6.3373), 1.00, 4.305 (Q3, 1.798–10.307), and 4.375 (Q4, 1.923–9.949), after adjusting for confounding variables.

Conclusion

Serum uric acid level has a J-shaped association with arterial stiffness in Korean postmenopausal women.

Visceral fat mass: is it the link between uric acid and diabetes risk?

BACKGROUND

Uric acid (UA) has been suggested as a novel risk factor for diabetes. However, its definite role in this prevalent disease is still the subject of much discussion because it is always accompanied with other major risk factors such as obesity and high visceral adiposity. In order to clarify the role of UA in diabetes, this study aimed to investigate the associations between plasma UA and fasting plasma glucose, HbA1c, lipid profile and inflammatory markers after accounting for the contribution of other diabetes risk factors such as BMI and VAT fat mass.

METHODS

In the present cross-sectional study, 100 non-diabetic middle-aged males (n = 48) and females (n = 52) were recruited. Central fat distribution measures including android to gynoid fat ratio, VAT and subcutaneous adipose tissue (SAT) fat mass were determined using dual-energy X-ray absorptiometry (DXA). Biochemical analysis was done using methods well established for clinical and research laboratories. Multiple linear regression analysis was performed to analyse the association between plasma UA and the biochemical and central fat distribution measures.

RESULTS

UA was positivly associated with body mass index (BMI) (r (98) = 0.42, P ≤ 0.001), android to gynoid fat ratio (r (98) = 0.62, P ≤ 0.001) and VAT fat mass (r (96) = 0.55, P ≤ 0.001). UA was also positively associated with plasma glucose (r (98) = 0.33, P ≤ 0.001), hemoglobin A1c (r (93) = 0.25, P = 0.014), plasma triglyceride (r _s (95) = 0.40, P ≤ 0.001), HDL cholesterol (r (98) = - 0.61, P ≤ 0.001) and CRP (r _s (98) = 0.23, P = 0.026). However, these associations were no longer significant after accounting for BMI or/and VAT fat mass. No significant association was observed between UA and SAT fat mass (r (97) = 0.02, P ≥ 0.05), Total cholesterol (r (98) = 0.03, P ≥ 0.05), LDL cholesterol (r (98) = 0.13, P ≥ 0.05), TNF-α (r (97) = 0.12, P ≥ 0.05) and IL-6 (r (96) = -0.02, P ≥ 0.05).

CONCLUSION

Results from this study suggest, for the first time, that the association between plasma UA and glucose in a non-diabetic population is not direct but rather dependent on VAT fat mass.

Hyperuricemia and risk of increased arterial stiffness in healthy women based on health screening in Korean population

Hyperuricemia is a risk factor for cardiovascular disease and is associated with increased arterial stiffness in high-risk populations. However, given the possible sex-related differences in the prevalence of hyperuricemia, the association between elevated serum uric acid (SUA) level and increased arterial stiffness has yielded conflicting results. We investigated the relationship between SUA and arterial stiffness in asymptomatic healthy subjects who underwent a health examination. Subjects who underwent a comprehensive health examination were enrolled. After exclusion of extensive confounding factors, 2,704 healthy subjects with coronary calcium score < 100 were evaluated in the final analysis. All subjects underwent brachial—ankle pulse wave velocity (baPWV) to detect arterial stiffness. The SUA was divided into quartiles for its association with arterial stiffness and was analyzed separately for men and women. The mean SUA level was significantly lower in women than in men. The baPWV was significantly elevated in subjects with the highest quartile of SUA in women, but not in men. After adjusting for age, smoking, systolic blood pressure, body mass index, estimated glomerular filtration rate, fasting plasma glucose, high-density lipoprotein-cholesterol, low-density lipoprotein-cholesterol, and coronary artery calcium score, the highest quartile of SUA in women was significantly associated with increased risk of high baPWV compared with the lowest quartile of SUA (OR = 1.7, p = 0.018), whereas in men, SUA level was not associated with high baPWV. Our study showed that elevated SUA is independently associated with increased baPWV in healthy Korean women, but not in men.

Does the serum uric acid level have any relation to arterial stiffness or blood pressure in adults with congenital renal agenesis and/or hypoplasia?

BACKGROUND

The relationship between serum uric acid and arterial stiffness or blood pressure is not clear. The serum uric acid level and its association with cardiovascular risk is not well known in patients with reduced renal mass. We aimed to investigate the relation between serum uric acid levels and arterial stiffness and also blood pressure in patients with congenital renal agenesis and/or hypoplasia.

MATERIAL AND METHODS

In this single center, cross-sectional study, a total of 55 patients (39 (% 70.9) with unilateral small kidney and 16 (%29.1) with renal agenesis) were included. The median age was 35 (21-50) years. The study population was divided into tertiles of serum uric acid (according to 2.40-3.96, 3.97-5.10, and 5.11-9.80 mg/dl cut-off values of serum uric acid levels). Official and 24-h ambulatory non-invasive blood pressures of all patients were measured. The arterial stiffness was assessed by pulse wave velocity (PWV).

RESULTS

PWV values were increased from first to third tertile (5.5 ± 0.6, 5.7 ± 0.8, 6.1 ± 0.7, respectively), but this gradual increase between tertiles did not reach significance. Linear regression analyses showed a positive correlation between serum uric acid levels and PWV (β = 0.40, p = 0.010), but no correlation was found between uric acid and daytime systolic blood pressure (β = 0.24, p = 0.345).

CONCLUSION

In congenital renal agenesis/hypoplasia, the serum uric acid level was positively correlated with arterial stiffness, but there was no correlation with blood pressure.

Peripheral arterial stiffness is associated with higher baseline plasma uric acid: A prospective cohort study

This prospective cohort study aimed at identifying association between uric acid (UA) and peripheral arterial stiffness. A prospective cohort longitudinal study was performed according to an average of 4.8 years’ follow-up. The demographic data, anthropometric parameters, peripheral arterial stiffness (carotid-radial pulse-wave velocity, cr-PWV) and biomarker variables including UA were examined at both baseline and follow-up. Pearson’s correlations were used to identify the associations between UA and peripheral arterial stiffness. Further logistic regressions were employed to determine the associations between UA and arterial stiffness. At the end of follow-up, 1447 subjects were included in the analyses. At baseline, cr-PWV (r = 0.200, p < 0.001) was closely associated with UA. Furthermore, the follow-up cr-PWV (r = 0.145, p < 0.001) was also strongly correlated to baseline UA in Pearson’s correlation analysis. Multiple regressions also indicated the association between follow-up cr-PWV (β = 0.493, p = 0.013) and baseline UA level. Logistic regressions revealed that higher baseline UA level was an independent predictor of arterial stiffness severity assessed by cr-PWV at follow-up cross-section. Peripheral arterial stiffness is closely associated with higher baseline UA level. Furthermore, a higher baseline UA level is an independent risk factor and predictor for peripheral arterial stiffness.

Glycated Albumin is Independently Associated With Arterial Stiffness in Non-Diabetic Chronic Kidney Disease Patients

Glycated albumin (GA) exhibits atherogenic effects and increased serum GA levels are associated with the development of cardiovascular complications in diabetic patients. GA production also increases with aging, oxidative stress, and renal dysfunction. We performed this study to further ascertain the association between GA and arterial stiffness in nondiabetic chronic kidney disease (CKD) patients. We enrolled 129 nondiabetic CKD patients. Arterial stiffness was measured by brachial-ankle pulse wave velocity (baPWV) using a volume plethysmographic instrument along with simultaneous measurements of GA. Insulin resistance was determined with the homeostatic model assessment. The estimated glomerular filtration rate was calculated using serum creatinine and cystatin C according to the CKD-EPI Creatinine-Cystatin C equation adjusted for age, sex, and race (eGFRcr-cys). Nondiabetic CKD patients with arterial stiffness (baPWV ≥1400 cm/s) showed higher GA levels than those without arterial stiffness (14.2 [8.7-20.2]% vs 13.0 [8.8-18.9]%, P = 0.004). In the subgroup analysis, the patients who had both a higher GA level and a lower eGFRcr-cys, showed the highest baPWV compared with patients with a higher GA or a lower GFR alone. By Spearman's correlation analysis, GA correlated significantly with baPWV (r = +0.291, P = 0.001) and fasting serum glucose level (r = +0.191, P = 0.030), whereas The homeostatic model assessment of insulin resistance did not show any significant correlation with baPWV. Systolic blood pressure (r = +0.401 P < 0.001), age (r = +0.574, P < 0.001), high-density lipoprotein (HDL)-cholesterol level (r = -0.317, P < 0.001), and eGFRcr-cys (r = -0.285, P = 0.002) had a significant correlation with baPWV. According to multivariable logistic regression analysis, higher GA and systolic blood pressure were the independent risk factors affecting arterial stiffness. Our results suggest that serum GA is a potential risk factor of arterial stiffness in nondiabetic CKD patients.

Serum Uric Acid, Gender, and Low Ankle Brachial Index in Adults With High Cardiovascular Risk

Uric acid (UA) has been reported to be associated with cardiovascular disease (CVD) in caucasians. However, it is unclear whether this association remains significant in a Chinese population. The present study aimed to investigate the association between UA and low ankle brachial index (ABI), a measurement of peripheral arterial disease, in Chinese patients. A total of 6262 hospital-based patients with high CVD risk were enrolled. Low ABI was defined as ABI ≤0.9 in either side. Low ABI was detected in 1390 (22.2%) patients. Higher UA was significantly associated with higher risk of low ABI and modified by gender (P = .0045). After adjusting for age, body mass index, total cholesterol, triglyceride, low-density lipoprotein, high-density lipoprotein, fasting glucose, hypertension, and smoking, participants in the highest quartile of UA exhibited 37% (odds ratio [OR]:1.37, 95% confidence interval [CI]: 1.03-1.82) higher risk of low ABI compared to those in the lowest quartile in men, while OR (95% CI) was 1.69 (1.29-2.22) for women. However, when kidney function was further adjusted, the associations were attenuated in both men and women and were significant only in women. The results were suggestive of higher UA associating with higher risk of low ABI in women, and the association was largely driven by kidney function, especially in men.

Serum uric acid level, blood pressure, and vascular angiotensin II responsiveness in healthy men and women

Uric acid is associated with hypertension and increased renin-angiotensin system activity, although this relationship diminishes after chronic exposure to high levels. Uric acid is more strongly associated with poor outcomes in women compared to men, although whether this is due to a sex-specific uric acid-mediated pathophysiology or reflects sex differences in baseline uric acid levels remains unknown. We examined the association between uric acid and vascular measures at baseline and in response to angiotensin-II challenge in young healthy humans. Fifty-two subjects (17 men, 35 premenopausal women) were studied in high-salt balance. Serum uric acid levels were significantly higher in men compared to women (328 ± 14 μmol/L vs. 248 ± 10 μmol/L, P < 0.001), although all values were within normal sex-specific range. Men demonstrated no association between uric acid and blood pressure, either at baseline or in response to angiotensin-II. In stark contrast, a significant association was observed between uric acid and blood pressure at baseline (systolic blood pressure, P = 0.005; diastolic blood pressure, P = 0.02) and in response to angiotensin-II (systolic blood pressure, P = 0.035; diastolic blood pressure, P = 0.056) in women. However, this sex difference lost significance after adjustment for baseline uric acid. When all subjects were stratified according to high (>300 μmol/L) or low (≤300 μmol/L) uric acid levels, only the low uric acid group showed a positive association between uric acid and measures of vascular tone at baseline and in response to angiotensin-II. Differences in uric acid-mediated outcomes between men and women likely reflect differences in exposure to increased uric acid levels, rather than a sex-specific uric acid-mediated pathophysiology.

Leptomeningeal collaterals are associated with modifiable metabolic risk factors

OBJECTIVE

We sought to identify potentially modifiable determinants associated with variability in leptomeningeal collateral status in patients with acute ischemic stroke.

METHODS

Data are from the Keimyung Stroke Registry. Consecutive patients with M1 segment middle cerebral artery ± intracranial internal carotid artery occlusions on baseline computed tomographic angiography (CTA) from May 2004 to July 2009 were included. Baseline and follow-up imaging was analyzed blinded to all clinical information. Two raters assessed leptomeningeal collaterals on baseline CTA by consensus, using a previously validated regional leptomeningeal score (rLMC).

RESULTS

Baseline characteristics (N = 206) were: mean age = 66.9 ± 11.6 years, median baseline National Institutes of Health Stroke Scale = 14 (interquartile range [IQR] = 11-20), and median time from stroke symptom onset to CTA = 166 minutes (IQR = 96-262). Poor collateral status at baseline (rLMC score = 0-10) was seen in 73 of 206 patients (35.4%). On univariate analyses, patients with poor collateral status at baseline were older; were hypertensive; had higher white blood cell count, blood glucose, D-dimer, and serum uric acid levels; and were more likely to have metabolic syndrome. Multivariate modeling identified metabolic syndrome (odds ratio [OR] = 3.22, 95% confidence interval [CI] = 1.69-6.15, p < 0.001), hyperuricemia (per 1mg/dl serum uric acid; OR = 1.35, 95% CI = 1.12-1.62, p < 0.01), and older age (per 10 years; OR = 1.34, 95% CI = 1.02-1.77, p = 0.03) as independent predictors of poor leptomeningeal collateral status at baseline.

INTERPRETATION

Metabolic syndrome, hyperuricemia, and age are associated with poor leptomeningeal collateral status in patients with acute ischemic stroke.