Effects of menopause and hormone replacement therapy on the associations of hyperuricemia with mortality

Sex distinctive patterns in the association between serum bicarbonate and uric acid levels among healthy adults. Qatar biobank data

Background

Uric acid is the final product of purine metabolism and is a potent plasma antioxidant but with pro-inflammatory effects. At high levels, it may increase the risk of developing multiple chronic diseases, such as gout, atherosclerosis, hypertension, and renal diseases. The aim of this study was to assess the sex-specific association between serum bicarbonate and uric acid levels among healthy adults.

Methodology

This retrospective cross-sectional study included 2,989 healthy Qatari adults (36.4 ± 11.1  years) from the Qatar Biobank database. Serum uric acid and bicarbonate levels were estimated alongside other serological markers. Participants free from chronic diseases were divided into four quartiles based on serum bicarbonate levels. The sex-specific relationship between serum bicarbonate and uric acid levels was assessed through univariate and multivariate analyses.

Results

In men, low serum uric acid levels were significantly associated with higher quartiles of serum bicarbonate levels after adjusting for age. The association remained significant after further adjustment for BMI, smoking, and renal function. The subgroup analysis using the restricted cubic spline method confirmed a significant dose-response association between the variation coefficients of uric acid by serum bicarbonate level in men with adjustments for age, BMI, smoking, and renal function. In women, no significant association was found between quartiles of serum bicarbonate and uric acid levels following the same adjustments. However, using the restricted cubic spline method, a significant bidirectional relation was demonstrated between serum bicarbonate and the variation coefficients of uric acid that were positive for serum bicarbonate levels below 25 mEq/L and negative at higher levels.

Conclusion

Serum bicarbonate levels are linearly associated with reduced serum uric acid levels among healthy adult men, which may be a potential protective factor against hyperuricemia-related complications. Further research is needed to determine the underlying mechanisms.

Gender-Specific and U-Shaped Relationship Between Serum Uric Acid and All-Cause Mortality Among Chinese Older Adults: A National Population-Based Longitudinal Study

Objectives: This study aimed to prospectively investigate gender-specific relationship between hyperuricemia and all-cause mortality among Chinese older adults. Methods: The study was based on the Chinese Longitudinal Healthy Longevity Survey (CLHLS) 2008-2018, a prospective nationwide cohort of older adults in China. Multivariate Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% CIs for all-cause mortality. Restricted cubic splines (RCS) were conducted to explore the dose-response relationship between SUA levels and all-cause mortality. Results: For older women, compared to the participants in the third quartile of SUA level, those in the highest quartile of SUA was associated with significantly higher risk of all-cause mortality in the fully adjusted model (HR: 1.41, 95% CI: 1.03-1.92). No significant associations between SUA levels and all-cause mortality were observed in older men. The present study further found a U-shaped non-linear relationship between SUA levels and all-cause mortality in both sexes of older population (P for non-linear <0.05). Conclusions: This study provided prospective epidemiological evidence for the predictive role of SUA on all-cause mortality among the Chinese aging population over 10 years of follow-up, while revealing considerable gender-related differences.

Association Between Uric Acid to HDL Cholesterol Ratio and Diabetic Complications in Men and Postmenopausal Women

AIM

Previous studies have implicated the uric acid to high-density lipoprotein cholesterol (HDL-C) ratio (UHR) was associated with type 2 diabetes. However, the association between UHR and diabetes-related vascular damages is still unclear.

METHODS

The total of 4551 patients with type 2 diabetes from the cross-sectional Environmental Pollutant Exposure and Metabolic Diseases in Shanghai study (METAL study) were enrolled. UHR was calculated as uric acid to HDL-C ratio. Cardiovascular disease (CVD) was defined as previously diagnosed with stroke, coronary heart disease, or peripheral arterial disease. Chronic kidney disease (CKD) was defined as estimated glomerular filtration rate ≤60 mL/min/1.73 m² and/or urinary albumin to creatinine ratio ≥30 mg/g. Fundus image was examined by trained individuals and degree of diabetic retinopathy (DR) was evaluated.

RESULTS

UHR was positively correlated with CVD (OR = 1.28, 95% CI: 1.02-1.61) and CKD (OR = 1.78, 95% CI: 1.39-2.27) after adjusting for all confounders. No association was found between UHR and DR. In stratified analyses, UHR was predominantly correlated with CVD in diabetic patients with age older than 65 (OR = 1.41, 95% CI: 1.08-1.85), female (OR = 1.43, 95% CI: 1.06-1.94) and BMI≥24kg/m² (OR = 1.57, 95% CI: 1.17-2.11). A 1-SD increment of UHR was also positively associated with CVD (OR 1.26, 95% CI 1.03, 1.15) and CKD (OR 1.28, 95% CI 1.20,1.39). UHR was positively associated with CKD in all subgroups analysis. No significant interaction effect was observed between UHR and all subgroup variables in CVD and CKD risk.

CONCLUSION

Our study reported a positive association between the UHR and diabetic-related vascular complications in men and postmenopausal women. The relationship between the UHR and DR seems to be uncertain and requires further investigation. And no significant interaction effect was observed between the UHR and all subgroup variables in CVD and CKD risk.

Correlation between Vitamin D and Uric Acid in Menopausal Women

Background : Vitamin D deficiency and hyperuricemia are global health problems in post-menopausal women in which parathyroid hormone increases hyperuricemia incidence. Aim : This research purpose to  determine correlation between vitamin D and uric acid levels in postmenopausal women Methods: This research is an observational analytic study with a cross-sectional study design conducted at University of North Sumatra Hospital and Network Hospital in Medan for 12 months on 40 postmenopausal women who met inclusion and exclusion criteria. The data will be analyzed descriptively to determine variables frequency distribution. Previously, normality test of numerical data is carried out. If the data is normally distributed, Pearson correlation test will be carried out, and if the data is not normally distributed, then Spearman correlation test will be used. Results : Mean vitamin D of the sample was 23.11 ng/mL with a standard deviation 4.43 and median value 23.5 ng/mL. while the mean uric acid was 7.52 mg/dL with a standard deviation 0.92 and median value 7.45 mg/dL. There is an inverse relationship between uric acid levels and Vitamin D, as evidenced by Pearson test correlation coefficient of -0.541 with p value = 0.001. Conclusion : There is an inverse correlation between Vitamin D and uric acid levels.

Association between serum uric acid and arterial stiffness in a large-aged 40-70 years old population

Arterial stiffness (AS), measured by arterial stiffness index (ASI), is a determinant in cardiovascular (CV) diseases. A high serum uric acid (SUA) level is a known risk factor for CV disease. The authors investigated the relationship between SUA and ASI in the middle-age UK Biobank population study. AS was defined as ASI > 10 m/s. A cross-sectional study was conducted from 126 663 participants. Participants were divided into four quartiles according to SUA levels and sex. Sex multivariate analyses were performed with adjustment for confounding factors. The average ASI for overall participants was 9.3 m/s (SD: 2.9); 9.9 m/s (SD: 2.8) for men and 8.7 m/s (SD: 2.9) for women (P < .001). Men presented higher SUA rate (351.3 mmol/L (SD:67.9)) than women (270.7 mmol/L (SD:64.4)), P < .001. In men multivariate analysis, SUA remained a determinant of AS, with an increase in the strength of the association between the quartiles, Q4 versus Q1, OR = 1.10 [1.05-1.16], P < .001, Q3 versus Q1, OR = 1.09 [1.04-1.14], P < .001 but not between Q2 and Q1 (P = .136). In women, SUA remained significant for AS, with an increase in the strength of the association between the quartiles, Q4 versus Q1, OR = 1.22 [1.15-1.30], P < .001, Q3 versus Q1, OR = 1.13 [1.07-1.19], P < .001 and no difference between Q2 and Q1 (P = .101). When applying continuous SUA values in the multivariate analysis, SUA remained significant (P < .001), with a Youden index value for men = 338.3 mmol/L and for women = 267.3 mmol/L. High SUA levels were associated with AS, suggesting that SUA could be used as a predictor of atherosclerosis.

The Role of Urate in Cardiovascular Risk in Adolescents and Young Adults With Hypertension, Assessed by Pulse Wave Velocity

Background

Urate is increasingly recognized as a cardiovascular risk factor. It has been associated with hypertension, metabolic syndrome, obesity, chronic kidney disease and diabetes. Its prognostic role is less clear. The aim of our study was to evaluate the association between serum urate and pulse wave velocity, a measure of arterial stiffness in hypertensive adolescents and young adults.

Methods

269 adolescents and young adults with hypertension were included in the study. From all, anthropometric, blood pressure, pulse wave velocity and serum urate measurements were made. Variables were compared between sex, participants with or without obesity and with or without elevated urate.

Results

In multiple regression analysis for urate as dependent variable gender and diastolic pressure were found to be statistically significant. The difference between urate levels were found between boys and girls (p < 0.001), obese and non-obese (p < 0.001); however, pulse wave velocity did not differ between hyper- and eu-uricemic group (p = 0.162).

Conclusion

Associations between urate, gender, diastolic blood pressure and obesity were confirmed, however, no significant associations between pulse wave velocity and urate were detected.

Urate transport in health and disease

Circulation of urate levels is determined by the balance between urate production and excretion, homeostasis regulated by the function of urate transporters in key epithelial tissues and cell types. Our understanding of these physiological processes and identification of the genes encoding the urate transporters has advanced significantly, leading to a greater ability to predict risk for urate-associated diseases and identify new therapeutics that directly target urate transport. Here, we review the identified urate transporters and their organization and function in the renal tubule, the intestinal enterocytes, and other important cell types to provide a fuller understanding of the complicated process of urate homeostasis and its role in human diseases. Furthermore, we review the genetic tools that provide an unbiased catalyst for transporter identification as well as discuss the role of transporters in determining the observed significant gender differences in urate-associated disease risk.

Serum uric acid level and all-cause and cardiovascular mortality in Chinese elderly: A community-based cohort study in Shanghai

BACKGROUND AND AIMS

The association between serum uric acid (SUA) and the all-cause and cardiovascular diseases (CVD) mortality remains controversial, but few studies based on the community population in Shanghai have been reported. We aimed to evaluate the association of SUA level with all-cause and CVD mortality in Chinese elderly based on a community-based cohort study in Shanghai of China.

METHODS AND RESULTS

A total of 12,071 eligible participants were included, with a cumulative follow-up period of 46,063.65 person-years and a median of 4.67 years. The time-dependent Cox regression model indicated that when SUA level was classified into quartile groups, no significant association was observed between SUA level and all-cause death in both men and women and between SUA level and CVD mortality in men. However, the HR (95%CI) between SUA groups and CVD death in women was 3.75 (1.49-9.43) for quartile 1, 3.66 (1.53-8.76) for quartile 2, and 2.98 (1.33-6.69) for quartile 4, respectively, when compared with the quartile 3 SUA level. A significant non-linear association was observed between SUA level and CVD death in elderly women. An increased risk of CVD death was observed among women with SUA level less than 4.30 mg/dL at the baseline, and a lower risk, among women with SUA level of 4.30-4.72 mg/dL at the baseline.

CONCLUSION

The non-linear association between SUA level and CVD mortality in elderly women suggests a potential benefit of controlling SUA level at4.30-4.72 mg/dL in elderly Chinese women.

Gender Difference in the Relationships between Inflammatory Markers, Serum Uric Acid and Framingham Risk Score

The purpose of the present study was to explore the role of gender in the relation of high-sensitivity C-reactive protein (hsCRP), white blood cell (WBC) count, and serum uric acid (UA) to the risk of future cardiovascular disease (CVD) events. In total, 404 workers were recruited to obtain the measurements of serum markers for CVD risk. Demographic data, nutrition, exercise, smoking, and alcohol consumption were assessed through a questionnaire. The Framingham Risk Score (FRS) was adopted to estimate the risk of future CVD events. Multiple linear regression models were used to determine CVD risk markers in relation to the FRS by gender. The hsCRP was not significantly correlated with the FRS for all workers after adjusting for covariates, including demographic data and health-related lifestyle. WBC count was positively correlated with FRS for all workers, but WBC count did not show an interaction with gender with respect to the FRS. Serum UA showed an interaction with gender on the FRS, and UA positively correlated with the FRS in males though not in females. With respect to CVD prevention, the WBC count can be used to monitor the risk for all workers. Due to a gender difference shown in the relationship between serum UA and the FRS, serum UA can be a monitor of the risk of future CVD events in male workers only.

27-Hydroxycholesterol regulates human SLC22A12 gene expression through estrogen receptor action

The excretion and reabsorption of uric acid both to and from urine are tightly regulated by uric acid transporters. Metabolic syndrome conditions, such as obesity, hypercholesterolemia, and insulin resistance, are believed to regulate the expression of uric acid transporters and decrease the excretion of uric acid. However, the mechanisms driving cholesterol impacts on uric acid transporters have been unknown. Here, we show that cholesterol metabolite 27‐hydroxycholesterol (27HC) upregulates the uric acid reabsorption transporter URAT1 encoded by SLC22A12 via estrogen receptors (ER). Transcriptional motif analysis showed that the SLC22A12 gene promoter has more estrogen response elements (EREs) than other uric acid reabsorption transporters such as SLC22A11 and SLC22A13, and 27HC‐activated SLC22A12 gene promoter via ER through EREs. Furthermore, 27HC increased SLC22A12 gene expression in human kidney organoids. Our results suggest that in hypercholesterolemic conditions, elevated levels of 27HC derived from cholesterol induce URAT1/SLC22A12 expression to increase uric acid reabsorption, and thereby, could increase serum uric acid levels.

Uric acid and its correlation with hypertension in postmenopausal women: A multi-ethnic study (Observational study)

We investigate the association of uric acid with hypertension among Han, Uygur, and Kazakh populations in the Xinjiang Province of Western China. Our study aims to evaluate the relationships of serum uric acid (SUA) with hypertension in the Chinese population according to the menopausal status. Medical data of 1684 Han, 1895 Uygur, and 294 Kazakh people was examined. The prevalence of hypertension was calculated by the quartiles of SUA. Correlation between hypertension-related risk factors calculated and compared between men and women. SUA was higher in men than in women. The level was significantly higher in postmenopausal than premenopausal women (4.40 ± 1.75 v.s 4.06 ± 1.63 mg/dl, P < .01). Logistic regression analysis showed Body mass index (BMI) [OR = 1.08, P < .01]; and eGFR<60 vs.≥60 [OR = 1.22, P = .04] were independent risk factors for hypertension in women. Age and diabetes were independent risk factors for the participants with hypertension [OR = 1.04, P < .01] and [OR = 2.24, P < .01]. High quartile SUA group has increased the risk for hypertension in postmenopausal women [OR = 1.34, P = .048]. We found that postmenopausal women have high SUA compared to premenopausal women. The high SUA quartiles uric acid may be an independent risk for hypertension in postmenopausal women.

Sex Differences in Urate Handling

Hyperuricemia, or elevated serum urate, causes urate kidney stones and gout and also increases the incidence of many other conditions including renal disease, cardiovascular disease, and metabolic syndrome. As we gain mechanistic insight into how urate contributes to human disease, a clear sex difference has emerged in the physiological regulation of urate homeostasis. This review summarizes our current understanding of urate as a disease risk factor and how being of the female sex appears protective. Further, we review the mechanisms of renal handling of urate and the significant contributions from powerful genome-wide association studies of serum urate. We also explore the role of sex in the regulation of specific renal urate transporters and the power of new animal models of hyperuricemia to inform on the role of sex and hyperuricemia in disease pathogenesis. Finally, we advocate the use of sex differences in urate handling as a potent tool in gaining a further understanding of physiological regulation of urate homeostasis and for presenting new avenues for treating the constellation of urate related pathologies.

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.

The relationships among hyperuricemia, body mass index and impaired renal function in type 2 diabetic patients

Chronic kidney disease (CKD) is a common chronic microvascular complication and the major cause of death in diabetic patients. This study was conceived to explore the possible mechanisms of how hyperuricemia and obesity contribute to renal function impairment in type 2 diabetic (T2DM) patients. A cross-sectional study in 609 participants recruited from a T2DM population in North China was conducted. The multiplicative interaction between body mass index (BMI) and uric acid (UA) level was assessed using an interaction term in a logistic regression analysis. Our results indicate that male T2DM patients having higher BMI (OR 1.711, p = 0.038), blood urine nitrogen (BUN) (OR 1.100, p = 0.034), and 24-hour urinary micro-albumin levels (OR 1.004, p = 0.021) were much more likely to have high UA. Whereas, for female T2DM patients, the OR of BMI, BUN, and triglyceride were 1.169 (p = 0.001), 1.337 (p = 0.000), and 1.359 (p = 0.006), respectively. In this study population, obesity and elevated UA work together to increase the risk of renal injury. In vitro experiments indicate that reactive oxygen species (ROS) production increased with UA treatment in human renal glomerular endothelial cells (HRGECs), while endothelial nitric oxide synthase (eNOS) production level dropped. UA also increased monocyte chemotactic protein-1 (MCP-1) expression and nuclear factor kappa B (NF-κB) activation. Taken together, our results indicate that high concentrations of UA lead to endothelial dysfunction through the activation of the inflammatory response and induction of oxidative stress, even in non-obese T2DM patients.

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.

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.

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.

Serum Uric Acid Level Predicts Progression of IgA Nephropathy in Females but Not in Males

Background

Immunoglobulin A nephropathy (IgAN) is one of most common forms of glomerulonephritis. At this point, the clinical impact of hyperuricemia on IgAN is not clear. The aim of the present study was to explore the clinical impact of hyperuricemia on the progression of IgAN.

Study Design

Multicenter retrospective cohort study.

Setting & Participants

935 IgAN patients who were diagnosed by kidney biopsy at Osaka University Hospital, Osaka General Hospital, and Osaka Rosai Hospital. were included in this study.

Predictor

Uric acid levels at renal biopsy.

Outcomes

The outcome of interest was the time from the kidney biopsy to the time when a 50% increase in the baseline serum creatinine level was observed, which was defined as "progression".

Measurements

The baseline characteristics according to the kidney biopsy at the time of diagnosis were collected from the medical records, and included age, gender, body mass index, hypertension, diabetes (use of antidiabetic drugs), serum levels of creatinine, urinary protein, smoking status, RAAS blockers and steroid therapy.

Results

An elevated serum uric acid level was an independent risk factor for progression in female patients (per 1.0 mg/dL, multivariate-adjusted incident rate ratio 1.33 [95% confidence interval 1.07, 1.64], P = 0.008) but not in male patients (1.02 [0.81, 1.29], P = 0.855). To control a confounding effect of renal function on an association between serum uric acid level and progression in female patients, age- and serum creatinine-matched and propensity score-matched analyses were performed, and these results also supported the effect by uric acid on kidney disease progression independent of basal kidney function.

Limitations

A cohort analyzed retorospectively.

Conclusions

This study revealed that an elevated uric acid level was an independent risk factor for ESKD in female IgAN patients. Therefore, uric acid might be a treatable target in female IgAN patients.

New and emerging biomarkers in cardiovascular disease

Cardiovascular disease (CVD) is the most common cause of death and disability worldwide. Therefore, great importance has been placed on the discovery of novel risk factors and metabolic pathways relevant in the prevention and management of CVD. Such research is ongoing and may continue to lead to better risk stratification of individuals and/or the development of new intervention targets and treatment options. This review highlights emerging biomarkers related to lipid metabolism, glycemia, inflammation, and cardiac damage, some of which show promising associations with CVD risk and provide further understanding of the underlying pathophysiology. However, their measurement methodology and assays will require validation and standardization, and it will take time to accumulate evidence of their role in CVD in various population settings in order to fully assess their clinical utility. Several of the novel biomarkers represent intriguing, potentially game-changing targets for therapy.

High Serum Uric Acid Levels Are Associated with All-Cause and Cardiovascular, but Not Cancer, Mortality in Elderly Adults

OBJECTIVES

To estimate the all-cause, cardiovascular, and cancer mortality risks associated with serum uric acid levels in elderly adults.

DESIGN

Cohort study.

SETTING

The Annual Geriatric Health Examination Program database from 2006 to 2010.

PATICIPANTS

Community-dwelling Taipei citizens aged 65 and older (N = 77,541).

MEASUREMENTS

Stratified according to sex, serum uric acid levels were analyzed in quartiles and as normal versus high categories. Mortality was determined by matching cohort identifications with national death files.

RESULTS

Men had significantly higher uric acid levels than women (P < .001), and mean levels increased with age (P < .001). Serum uric acid levels (normal vs high) were an independent risk factor for all-cause and cardiovascular mortality in men and women, with the strongest association found for cardiovascular mortality. The association between serum uric acid levels and cardiovascular mortality was independent of other cardiovascular risk factors such as hypertension, diabetes mellitus, hyperlipidemia, and glomerular filtration rate levels. When levels were analyzed as quartiles, men with levels in the second quartile had the lowest hazard ratios for all-cause and cardiovascular mortality.

CONCLUSION

High serum uric acid levels are associated with greater risk of all-cause and cardiovascular mortality but not cancer mortality in elderly adults. Further studies are warranted to investigate the prognostic implications and potential utility in the monitoring of therapy.

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.