Usefulness of uric acid to predict changes in C-reactive protein and interleukin-6 in 3-year period in Italians aged 21 to 98 years

A nonlinear correlation between the serum uric acid to creatinine ratio and the prevalence of hypertension: a large cross-sectional population-based study

OBJECTIVE

To explore the relationship between the serum uric acid to creatinine (UA/Cr) ratio and the prevalence of hypertension.

METHODS

In this cross-sectional study, we included 8571 individuals from the China Health and Nutrition Survey. Logistic regression analysis and restricted cubic spline (RCS) were used to analyze the relationship between the UA/Cr ratio and hypertension.

RESULTS

Compared with individuals without hypertension, individuals with hypertension had higher UA/Cr ratios. Multivariate logistic regression analysis showed that a higher UA/Cr ratio was closely related to a higher risk of hypertension (as a continuous variable, OR: 1.054, 95% CI: 1.014-1.095, p = 0.007; as a categorical variable, Q3 vs. Q1, OR: 1.183, 95% CI: 1.011-1.384, p = 0.035; Q4 vs. Q1, OR: 1.347, 95% CI: 1.146-1.582, p < 0.001). Subgroup analysis revealed that the correlation between the UA/Cr ratio and hypertension risk was stable in all subgroups except for the subgroup with diabetes and the subgroup with a BMI ≥ 28 kg/m2 (p < 0.05). Sensitivity analysis confirmed the robustness of the relationship between a higher UA/Cr ratio and a higher risk of hypertension (p < 0.05). The RCS showed that the UA/Cr ratio was nonlinearly related to hypertension risk. Further threshold effect showed that only a UA/Cr ratio less than 5.0 was related to hypertension risk (OR: 1.178, 95% CI: 1.086-1.278, p < 0.001), and the 2-piecewise linear regression model was superior to the 1-line linear regression model (p < 0.05).

CONCLUSION

The UA/Cr ratio was associated with the prevalence of hypertension.

Systemic inflammation markers independently associated with increased mortality in individuals with hyperuricemia: Results from the NHANES prospective cohort study

BACKGROUND

Hyperuricemia is associated with increased systemic inflammation. The systemic immune-inflammation index (SII) and systemic inflammation response index (SIRI) are novel systemic inflammation markers and prognostic markers. However, no studies have evaluated the association between the SII/SIRI and mortality risk in individuals with hyperuricemia. This study aimed to investigate the predictive value of the SII and SIRI for all-cause and cardiovascular mortality in a large cohort of hyperuricemia patients.

METHODS

We conducted a prospective cohort study using data from the National Health and Nutrition Examination Survey (NHANES) 2001-2020. Hyperuricemia was defined as serum uric acid (SUA) levels of ≥7 mg/dL in men and ≥6 mg/dL in women. The SII and SIRI were calculated based on complete blood count parameters. Associations with all-cause and cardiovascular mortality were analyzed using Cox proportional hazards models. Nonlinearity and effect modification were assessed using restricted cubic splines (RCS) and interaction analysis.

RESULTS

Among the 6181 participants with hyperuricemia aged 20 years and older, over a total 181 months of follow-up, there were 936 all-cause deaths, of which 195 were cardiovascular mortality. In the fully adjusted models, the hazard ratios (HRs) were 1.73 (95% CI 1.42-2.13) for the SII and 2.18 (95% CI 1.82-2.62) for the SIRI with all-cause mortality. The adjusted HRs were 2.08 (95% CI 1.37-3.14) for the SII and 2.32 (95% CI 1.56-3.45) for the SIRI with cardiovascular mortality. Spline models identified nonlinear U-shaped (SII) and J-shaped (SIRI) relationships of inflammation markers with mortality.

CONCLUSIONS

Elevated SII and SIRI are independent predictors of mortality in hyperuricemia patients. These inflammatory biomarkers may improve risk stratification in this high-risk population. Further research should evaluate utility in guiding preventive interventions.

[Association between serum uric acid and airflow obstruction based on the health-checkup population]

OBJECTIVE

To investigate the association between serum uric acid, pulmonary function and airflow obstruction in Chinese Taiwan healthy subjects.

METHODS

All the cross-sectional analysis was performed in the population over 40 years old using the physical examination data of Chinese Taiwan MJ Health Resource Center between 1996 and 2016 stratification by gender. The correlation analyses between serum uric acid were done and multivariate Logistic regression analysis was used to explore the effect of serum uric acid on airflow obstruction.

RESULTS

A total of 35 465 people were included in the study, including 16 411 men and 19 054 women. Among them, the serum uric acid concentration of men was higher than that of women, and the serum uric acid concentration of the people with airflow obstruction was higher than that of the people without airflow obstruction. There was a negative correlation between serum uric acid level and the forced expiratory volume in one second (FEV1) and the force vital capacity (FVC) in women (P < 0.05), but in men the correlation didn' t exist (P>0.05). After adjusting for age, education, smoking status, drinking status, work strength, body mass index, history of cough, history of hypertension, history of diabetes, history of dyslipidemia, white blood cells and blood albumin, the airflow obstruction in women was more likely to exist with the serum uric acid elevated (OR=1. 12, 95%CI: 1.02-1.22, P < 0.05). The results showed that women with hyperuricemia were more likely to have airflow obstruction than those without hyperuricemia (OR=1.36, 95%CI: 1.06-1.75, P < 0.05). There was no correlation between serum uric acid concentration and airflow obstruction in men (OR=1.04, 95%CI: 0.96-1.13, P>0.05), also the hyperuricemia and airflow obstruction (OR=1.12, 95%CI: 0.89-1.39, P>0.05).

CONCLUSION

There is a negative correlation between serum uric acid and FEV1 and FVC in relatively healthy women, and there is an association between elevated serum uric acid and airflow obstruction in women, but not in men. Further prospective studies are needed to explore whether high serum uric acid level can increase the risk of airflow obstruction.

Joint association of serum urate and healthy diet with chronic obstructive pulmonary disease incidence: results from the UK Biobank study

Background: The role of serum urate (SU) levels in the development of chronic obstructive pulmonary disease (COPD) remains a topic of debate, and it is unclear whether a healthy diet can mitigate the impact of SU on COPD risk. The objective of this study is to examine whether and to what extent a healthy diet can reduce the risk of COPD in relation to SU levels. Methods: The cohort analysis included 155 403 participants from the UK Biobank. SU levels were measured at the time of recruitment. A healthy diet score was calculated based on the consumption of vegetables, fruits, fish, processed meats, unprocessed red meat, whole grains, and refined grains. The Cox proportional hazards model was used to analyze the associations between SU levels, a healthy diet score, and the risk of COPD. Results: During a follow-up period of 1 409 969 person-years, 2918 incident cases of COPD were identified. Compared with the lowest SU level group, the hazard ratio (HR) and 95% confidence interval (CI) for COPD were 1.17 (1.03, 1.34) for participants with the highest SU level (hyperuricemia), indicating a positive association. Additionally, a dose-response relationship was observed between SU levels and the incidence of COPD (P-value for overall <0.0001). In the combined effect analysis, compared to individuals with high SU (hyperuricemia) + a low diet score (diet score <4), those with normal SU + a high diet score (diet score ≥4) had a HR (95% CI) of 0.75 (0.65, 0.87) for COPD. Conclusions: In summary, there is a positive association between SU levels and the risk of COPD. Furthermore, a healthier diet can mitigate the risk of COPD associated with high SU levels.

Robust positive association between serum urate and the risk of chronic obstructive pulmonary disease: hospital-based cohort and Mendelian randomisation study

BACKGROUND

Chronic obstructive pulmonary disease (COPD) and hyperuricaemia are both characterised by systemic inflammation. Preventing chronic diseases among the population with common metabolic abnormality is an effective strategy. However, the association of hyperuricaemia with the higher incidence and risk of COPD remains controversial. Therefore, replicated researches in populations with distinct characteristics or demographics are compellingly warranted.

METHODS

This cohort study adopted a design of ambispective hospital-based cohort. We used propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) to minimise the effects of potential confounding factors. A Cox regression model and restricted cubic spline (RCS) model were applied further to assess the effect of serum urate on the risk of developing COPD. Finally, we conducted a two-sample Mendelian randomisation (MR) analysis to explore evidence of causal association.

RESULTS

There is a higher incidence in the population with hyperuricaemia compared with the population with normal serum urate (22.29/1000 person-years vs 8.89/1000 person-years, p=0.009). This result is robust after performing PSM (p=0.013) and IPTW (p<0.001). The Cox model confirms that hyperuricaemia is associated with higher risk of developing COPD (adjusted HR=3.35 and 95% CI=1.61 to 6.96). Moreover, RCS shows that the risk of developing COPD rapidly increases with the concentration of serum urate when it is higher than the reference (420 µmol/L). Finally, in MR analysis, the inverse variance weighted method evidences that a significant causal effect of serum urate on COPD (OR=1.153, 95% CI=1.034 to 1.289) is likely to be true. The finding of MR is robust in the repeated analysis using different methods and sensitivity analysis.

CONCLUSIONS

Our study provides convincing evidence suggesting a robust positive association between serum urate and the risk of developing COPD, and indicates that the population with hyperuricaemia is at high risk of COPD in the Chinese population who seek medical advice or treatment in the hospital.

Longitudinal changes in high sensitivity C-reactive protein associated with serum uric acid in the Korean Genome and Epidemiology Study

Cross-sectional studies support the role of serum uric acid (SUA) in inflammation, but evidence from cohort studies is scarce. Longitudinal associations between SUA and high-sensitivity C-reactive protein (hs-CRP) were examined in the general population. Data for participants from the Health Examinees-Gem cohort (n = 50,028; 40-69 years; 67% women) who were examined between 2004 and 2013 and followed up until 2016 were analyzed. SUA and hs-CRP were measured at baseline and during follow-up. SUA was evaluated as a continuous variable and was also divided into sex-specific quartiles. Mean hs-CRP levels at follow-up were evaluated using multivariable proportional odds regression, with non-linear smoothed baseline hs-CRP levels serving as a covariate. Selected pathological markers were also examined in relation to hs-CRP. Increased levels of SUA at baseline were related to increased levels of hs-CRP at follow-up [regression coefficient per mg/dL increase in baseline SUA (β) = 0.08, 95% confidence interval (CI), 0.040-0.128]. A dose-response relationship was observed, (P for linear trend = 0.0015). The mean values of hs-CRP were highest among participants with the highest follow-up but lowest baseline SUA levels. Elevated hs-CRP levels at follow up (> 3 mg/L) were positively related to fasting blood glucose levels, triglycerides levels, liver enzymes, and blood pressure, but negatively related to high density lipoprotein cholesterol levels per unit increase in baseline hs-CRP. High SUA levels were associated with high hs-CRP levels, suggesting a potential role of SUA in inflammation. However, additional research is needed to confirm these findings.

Evaluation of Haematological Parameters and Uric Acid in the Diagnosis of Late Onset Neonatal Sepsis

Introduction A number of parameters studied in a whole blood count can be helpful in the diagnosis of neonatal sepsis. The platelet/lymphocyte ratio (PLR) is a systemic inflammatory marker in early sepsis and has been used as a diagnostic indicator in cardiovascular events and cancer. Being one of the major antioxidants in human biological fluids, serum uric acid is responsible for neutralising free radicals. The red cell distribution width/platelet ratio (RPR) is a diagnostic marker in adult inflammatory diseases. The objective of our study is to investigate the relationship of late neonatal sepsis with whole blood count parameters and serum uric acid levels. Materials and methods Newborns older than postnatal three days who had clinical and laboratory findings of sepsis were included in the study. The study included 140 newborns who were divided into three groups, 53 in the culture-proven late sepsis group, 47 in the clinical sepsis group, and 40 in the healthy control group. The whole blood count parameters and serum uric acid levels were examined in both the clinical sepsis and proven sepsis patients at the time when they were diagnosed with sepsis. Results The birth week was significantly lower in the evidenced and clinical sepsis patients compared to the healthy control group. Development of late sepsis was significantly higher in the male gender than in healthy controls. Serum uric acid levels were significantly higher in proven or clinical sepsis than in healthy controls. The level of serum uric acid (3.77±1.6) in proven sepsis was significantly higher than the control group (2.83±1.1). The uric acid level had an area under the curve (AUC) 0.552-0.717, 35% sensitivity, 95% specificity, 94.6% positive predictive value (PPV), and 36.9% negative predictive value (NPV) in the diagnosis of proven and clinical late sepsis. Neutrophil/lymphocyte ratio (NLR) was significantly higher in proven sepsis than in healthy newborns and was higher in the clinical sepsis group than in the proven sepsis group (p: 0.002). While the mean eosinophil value was 618.5±472.1 in proven sepsis, it was 549.3±294.9 in the control group and there was a statistically significant difference between the two groups (p: 0.036). Conclusion In late-onset neonatal sepsis, the NLR level was higher, and the eosinophil level was lower in the clinical sepsis patients than in healthy newborns. We believe that a higher level of serum uric acid in sepsis is effective in the early diagnosis of patients who also had other clinical findings of sepsis.

Negative Effects of Chronic High Intake of Fructose on Lung Diseases

In the modern diet, excessive fructose intake (>50 g/day) had been driven by the increase, in recent decades, of the consumption of sugar-sweetened beverages. This phenomenon has dramatically increased within the Caribbean and Latin American regions. Epidemiological studies show that chronic high intake of fructose related to sugar-sweetened beverages increases the risk of developing several non-communicable diseases, such as chronic obstructive pulmonary disease and asthma, and may also contribute to the exacerbation of lung diseases, such as COVID-19. Evidence supports several mechanisms—such as dysregulation of the renin−angiotensin system, increased uric acid production, induction of aldose reductase activity, production of advanced glycation end-products, and activation of the mTORC1 pathway—that can be implicated in lung damage. This review addresses how these pathophysiologic and molecular mechanisms may explain the lung damage resulting from high intake of fructose.

Research Progress on the Relationship between Dietary Patterns and Hyperuricemia

As the final metabolite of purine metabolism, uric acid is critically associated with human health. The serum uric acid level is regulated by diet and the metabolic capacity of the human body. The impaired control of uric acid metabolism and excretion is associated with the increased level of serum uric acid, which ultimately results in hyperuricemia. Hyperuricemia is the "fourth-highest" after hypertension, hyperglycemia, and hyperlipidemia. With progress made in the relationship between diet and hyperuricemia, different dietary patterns and lifestyles have been discussed, such as exercise, the amount intake of meat, seafood, supplements with omega-3 fatty acids, sugar-sweetened soft drinks and energy drinks, and lower-fat-containing foods as well as drinking beer, wine, and spirits in the present article. This study demonstrated that a lower risk of hyperuricemia is substantially correlated with higher baseline adherence to MeDiet, and plant polyphenols can combat hyperuricemia by blocking xanthine oxidase.

Effects of uric acid-lowering therapy in patients with essential arterial hypertension

OBJECTIVES

Asymptomatic hyperuricemia (AHU) is elevated serum uric acid (UA) without symptoms. This study aimed to determine the effects of AHU treatment with allopurinol on selected hypertension-mediated organ damage (HMOD) indices in patients with uncomplicated essential arterial hypertension (AH).

METHODS

Patients aged 30-70 years with AHU and AH grade 1-2 with adequate blood pressure (BP) control, without previous urate-lowering therapy (ULT), were divided into two groups: (a) ULT (receiving allopurinol) and (b) control (age- and sex-matched patients without ULT). Both received a UA-lowering diet. BP (office, 24 h and central), echocardiographic parameters, carotid intima-media thickness (IMT) and lab tests [high-sensitivity C-reactive protein (hs-CRP)] were measured at baseline and at 6 months follow-up.

RESULTS

Of 100 participants, 87 (44 ULT, 43 controls) completed the study. At 6 months follow-up, there was a greater reduction in serum UA concentration in the ULT group than in the control group. Patients receiving allopurinol had significant reductions in office systolic and diastolic BP, central systolic BP, pulse pressure, IMT (0.773 ± 0.121 vs. 0.752 ± 0.13 mm, P = 0.044) and hs-CRP (3.36 ± 2.73 vs. 2.74 ± 1.91 mg/L, P = 0.028) compared to controls. Multivariate regression analysis revealed the independent relationship between reduction in IMT and UA lowering (P < 0.026).

CONCLUSION

In patients with AH and AHU, treatment with allopurinol leads to improvement in BP control and reduction in HMOD intensity, in particular IMT. The decrease in hs-CRP concentration associated with ULT may have a beneficial effect on a patient's long-term prognosis.

Uric Acid and Oxidative Stress-Relationship with Cardiovascular, Metabolic, and Renal Impairment

Background: The connection between uric acid (UA) and renal impairment is well known due to the urate capacity to precipitate within the tubules or extra-renal system. Emerging studies allege a new hypothesis concerning UA and renal impairment involving a pro-inflammatory status, endothelial dysfunction, and excessive activation of renin–angiotensin–aldosterone system (RAAS). Additionally, hyperuricemia associated with oxidative stress is incriminated in DNA damage, oxidations, inflammatory cytokine production, and even cell apoptosis. There is also increasing evidence regarding the association of hyperuricemia with chronic kidney disease (CKD), cardiovascular disease, and metabolic syndrome or diabetes mellitus. Conclusions: Important aspects need to be clarified regarding hyperuricemia predisposition to oxidative stress and its effects in order to initiate the proper treatment to determine the optimal maintenance of UA level, improving patients’ long-term prognosis and their quality of life.

The Influence of Serum Uric Acid on the Brain and Cognitive Dysfunction

Uric acid is commonly known for its bad reputation. However, it has been shown that uric acid may be actively involved in neurotoxicity and/or neuroprotection. These effects could be caused by oxidative stress or inflammatory processes localized in the central nervous system, but also by other somatic diseases or systemic conditions. Our interest was to summarize and link the current data on the possible role of uric acid in cognitive functioning. We also focused on the two putative molecular mechanisms related to the pathological effects of uric acid-oxidative stress and inflammatory processes. The hippocampus is a prominent anatomic localization included in expressing uric acid's potential impact on cognitive functioning. In neurodegenerative and mental disorders, uric acid could be involved in a variety of ways in etiopathogenesis and clinical presentation. Hyperuricemia is non-specifically observed more frequently in the general population and after various somatic illnesses. There is increasing evidence to support the hypothesis that hyperuricemia may be beneficial for cognitive functioning because of its antioxidant effects but may also be a potential risk factor for cognitive dysfunction, in part because of increased inflammatory activity. In this context, gender specificities must also be considered.

Serum urate is related to subclinical inflammation in asymptomatic hyperuricaemia

OBJECTIVE

Asymptomatic hyperuricaemia (AHU) is associated with inflammatory disorders, including cardiovascular disease. Uric acid (UA) lowering therapies may reduce the risk of appearance or the progression of these comorbidities. In this work, we investigated the relationship between serum UA levels and inflammation in subjects with AHU.

METHODS

Serum levels of high-sensitivity CRP (hsCRP), TNF-α and IL-6, and mRNA expression of TNFa and IL6 in peripheral blood mononuclear cells were measured in individuals with AHU and without comorbid conditions and in a control group with similar characteristics and normal serum UA levels. Additionally, we determined the variations in the inflammatory profile in a subgroup of subjects after 6 months of treatment with allopurinol.

RESULTS

Subjects at higher tertiles of serum UA presented higher levels of hsCRP and increased serum and mRNA expression levels of both cytokines (P < 0.001). UA levels constituted an independent predictor of increased levels of inflammatory parameters in multiple regression models (P < 0.001) and a risk factor for the presence of a subclinical inflammation in multivariate logistic regression (P < 0.001). Allopurinol reduced UA and serum and mRNA expression of inflammatory cytokines (P < 0.001). There was a significant correlation between the variations in serum UA and the variations in serum TNF-α (P < 0.01) and IL-6 (P < 0.05), and mRNA expression of these cytokines (P < 0.05). This association remained significant and independent (P < 0.01).

CONCLUSION

In subjects with AHU, serum UA may be an inductor of subclinical inflammation. Therapeutic reduction of serum UA was associated with a modulation of the inflammatory profile.

Serum uric acid as a predictor for nephritis in Egyptian patients with systemic lupus erythematosus

OBJECTIVE

Lupus nephritis (LN) is closely associated with hyperuricemia, and uric acid is considered a risk factor for renal involvement in systemic lupus erythematosus (SLE). This study aimed to examine the association between serum uric acid (SUA) level and LN development and progression in SLE patients with normal renal function.

METHODS

A total of 60 SLE patients with normal renal function from Ain Shams University Hospital were selected and assigned to group 1 (30 patients with LN) and group 2 (30 patients without LN). All patients were subjected to history taking, clinical examination, disease activity assessment based on SLE disease activity index (SLEDAI) and renal SLEDAI (SLEDAI-R) scores, and laboratory investigations, including as SUA, complete blood count, blood urea nitrogen (BUN), serum creatinine, creatinine clearance, urine analysis, protein/creatinine ratio, 24-h urinary protein excretion, Antinuclear antibodies (ANA), anti-dsDNA antibody, and serum complement (C3, C4).

RESULTS

Disease duration, SLEDAI score, and SUA level were higher in group 1 than in group 2 (p < 0.001). SUA level was positively correlated with SLEDAI and SLEDAI-R scores, proteinuria, urinary casts, renal biopsy class, disease activity and chronicity indices, BUN level, and serum creatinine level but was negatively correlated with creatinine clearance (p < 0.05). SUA was a predictor of LN development in SLE patients (sensitivity, 83.3%; specificity, 70%).

CONCLUSION

SUA is associated with the development of lupus nephritis in patients with normal kidney function also SUA in-dependently correlated with disease activity and chronicity in LN.

Hyperuricemia Is Not Predictive of Long-Term Outcome in Patients with Stable Chronic Obstructive Pulmonary Disease

BACKGROUND

Although the association of hyperuricemia with an increased risk of mortality has been demonstrated in the context of acute exacerbation of chronic obstructive pulmonary disease (COPD), the long-term outcomes of hyperuricemia have not been studied in the case of stable COPD.

METHODS

We retrospectively analyzed baseline data of 240 men with stable COPD enrolled in the Korea Obstructive Lung Disease cohort. We evaluated associations between serum uric acid levels and clinical parameters, risk factors for all-cause mortality, and acute exacerbation of COPD.

RESULTS

The mean age of subjects was 66.4 ± 7.7 years, and the median follow-up time was 5.9 years. We identified no significant difference in terms of lung function or laboratory findings between patients with hyperuricemia and those without. Serum uric acid level was negatively associated with systemic inflammation indicated by neutrophil-lymphocyte ratio (r = -0.211, P = 0.001). Univariate Cox regression analysis revealed hyperuricemia to not be associated with an increased risk of all-cause mortality in men with stable COPD (hazard ratio [HR], 0.580; 95% confidence interval [CI], 0.250-1.370; P = 0.213). In the multivariate Cox regression model, hyperuricemia was not an independent predictor of acute exacerbation (HR, 1.383; 95% CI, 0.977-1.959; P = 0.068).

CONCLUSION

Among men with stable COPD, hyperuricemia is not an independent predictor of all-cause mortality or future acute exacerbation of COPD. These results differ from those of previous studies on patients with acute exacerbation of COPD.

Anthocyanins in berries exhibited anti-atherogenicity and antiplatelet activities in a metabolic syndrome population

Metabolic syndrome (MetS) is a global challenge for atherosclerosis. It was hypothesized that a four-week consumption of anthocyanin supplements by MetS patients who had three or more risk factors linked with metabolic syndrome would have a greater improvement in cardiometabolic biomarkers and would also reduce the risk of thrombosis. A total of 55 participants in two groups of Normal healthy and MetS (age 25-75y) were given 320 mg anthocyanin supplements twice daily for 4 weeks. Platelet coagulant activities, lipid profiles, fasting blood glucose, and inflammatory and oxidative stress biomarkers were measured before and after supplementation to evaluate the atheroprotective effects of anthocyanins in the study subjects. Four weeks of anthocyanin supplementation significantly decreased cardiometabolic risk factors including the average serum fasting blood glucose (FBG) (by 13.3%, P < .05) and lipid profiles by significant reduction in triglyceride (by 24.9%, P < .05) and LDL-C (by 33.1%, P < .05) in the MetS group. Anthocyanin supplementation also decreased high sensitivity C-reactive protein (hs-CRP) level (by 28%, P < .05) in females. However, no significant differences in serum UA (uric acid) and HDL-C were observed between anthocyanin pre- and post-treatment in both groups. Moreover, Anthocyanin supplements decreased ADP-induced platelet activation configuration expressed as P-selectin by 40% (P < .05). There was a positive correlation between decreased hs-CRP values and the levels of LDL-C and FBG in the MetS group (P < .05). These results support the hypothesis that anthocyanin supplementation exerts anti-atherogenicity effects by improving cardiometabolic risk factors and reducing thrombogenicity in the MetS population.

Asymptomatic Hyperuricemia Associates with Cardiometabolic Risk Indicators in Overweight/Obese but Not in Lean Adolescents

PURPOSE

In overweight/obese adolescents, asymptomatic hyperuricemia is associated with increased prevalence of metabolic syndrome, its components, and a higher cardiometabolic risk. Whether similar associations exist in lean hyperuricemic adolescents is unknown.

SUBJECTS AND METHODS

In 2424 adolescents (51.9% females) aged 16-19 years, anthropometric variables, blood pressure, uric acid, glucose, insulin, lipid profile, inflammatory markers, and renal function were determined. Continuous cardiometabolic score was calculated. Normouricemic vs hyperuricemic subjects were compared among lean and overweight/obese individuals of both sexes.

RESULTS

Females (5.4%) and males (13.3%) presented with hyperuricemia; among them 63% of females and 53% of males were lean. In both sexes, hyperuricemic lean and hyperuricemic overweight/obese adolescents displayed similar uric acid concentrations (eg, males: 455±30 vs 461±32 µmol/L, respectively, p=0.933). Lean normouricemic adolescents manifested significantly lower uric acid levels than their overweight/obese peers (eg, males: 333±46 vs 357±41 µmol/L, respectively, p<0.001). Lean normouricemic and hyperuricemic subjects presented similar cardiometabolic score (eg, males: 2.60±0.67 vs 2.64±0.60, respectively, p=0.998); among overweight/obese adolescents those with hyperuricemia displayed higher scores compared with their normouricemic counterparts (eg, males: 3.36±1.04 vs 4.21±1.65, respectively, p<0.001). A decision-tree model revealed phenotypes associated with higher uricemia, however, distribution of individuals with hyperuricemia among phenotypes was random.

CONCLUSION

In lean adolescents, hyperuricemia is not associated with cardiometabolic profile indicating an increased risk. Existence of this rather prevalent phenotype remains undetected unless lean and overweight/obese subjects are analyzed separately. Longitudinal studies are needed to elucidate the potential clinical consequences of asymptomatic hyperuricemia in lean subjects in later life.

Approximate Mortality Risks between Hyperuricemia and Diabetes in the United States

Aim: This study aimed to compare mortality risks across uric acid (UA) levels between non-diabetes adults and participants with diabetes and to investigate the association between hyperuricemia and mortality risks in low-risk adults. Methods: We analyzed data from adults aged >18 years without coronary heart disease and chronic kidney disease (n = 29,226) from the National Health and Nutrition Examination Survey (1999–2010) and the associated mortality data (up to December 2011). We used the Cox proportional hazards models to examine the risk of all-cause and cause-specific (cardiovascular disease (CVD) and cancer) mortality at different UA levels between adults with and without diabetes. Results: Over a median follow-up of 6.6 years, 2069 participants died (495 from CVD and 520 from cancers). In non-diabetes adults at UA ≥ 5 mg/dL, all-cause and CVD mortality risks increased across higher UA levels (p-for-trend = 0.037 and 0.058, respectively). The lowest all-cause mortality risk in participants with diabetes was at the UA level of 5–7 mg/dL. We set the non-diabetes participants with UA levels of <7 mg/dL as a reference group. Without considering the effect of glycemic control, the all-cause mortality risk in non-diabetes participants with UA levels of ≥7 mg/dL was equivalent to risk among diabetes adults with UA levels of <7 mg/dL (hazard ratio = 1.44 vs. 1.57, p = 0.49). A similar result was shown in CVD mortality risk (hazard ratio = 1.80 vs. 2.06, p = 0.56). Conclusion: Hyperuricemia may be an indicator to manage multifaceted cardiovascular risk factors in low-risk adults without diabetes, but further studies and replication are warranted.

Long-term prognostic impact of hyperuricemia in community

The debate whether an elevated level of serum uric acid (SUA) is an independent marker of cardiovascular risk is still going on. We examined morbidity and mortality related to SUA and hyperuricemia in a well-characterized population with very long follow-up. Study included 4696 participants (aged 30-59 years at baseline) of the coronary heart disease (CHD) Study of the Finnish Mobile Clinic Health Examination Survey. Adjusted hazard ratios (HRs) of hyperuricemia (defined as ≥360 µmol/l and ≥420 µmol/l) and SUA quintiles for mortality and adverse cardiovascular outcomes are reported. During the mean follow up of 30.6 years there were 2723 deaths, 887 deaths for CHD of which 340 were classified as sudden cardiac deaths, 1642 hospitalizations due to CHD and 798 hospitalizations due to congestive heart failure. After adjusting to baseline risk factors and presence of cardiovascular diseases as well as the use of diuretics there were no significant differences in the risk of any of the outcomes when analyzed either according to quintiles of SUA or using a cut-off point SUA ≥360 µmol/l for hyperuricemia. Only a rare finding of hyperuricemia SUA ≥420 µmol/l among women (n = 17, 0.9%) was independently associated with significantly higher risk of mortality (adjusted HR: 2.59, 95% CI: 1.54-4.34) and a combination end-point of major adverse cardiac events (MACEs) (HR: 2.69; 95% CI: 1.56-4.66). SUA was not an independent indicator of morbidity and mortality, with the exception of particularly high levels of SUA among women.

Serum Uric Acid to Creatinine Ratio Independently Predicts Incident Metabolic Syndrome Among Community-Dwelling Persons

BACKGROUND

Metabolic syndrome (MetS) is related to the increased risk of major cardiovascular disease. The link between high serum uric acid (SUA) and creatinine (Cr) levels is causally related to MetS and its components. However, whether renal function-normalized SUA [i.e., SUA to Cr ratio (SUA/Cr)] predicts incident MetS and its components remains inconclusive.

MATERIALS AND METHODS

We conducted a prospective cohort study designed as part of the Nomura study. The subjects comprised 447 men ages 68 ± 10 years and 625 women ages 68 ± 9 years from a rural village, and 155 (34.7%) men and 310 women (49.6%) had MetS at baseline. We found participants who underwent a similar examination 3 years later and analyzed the relationship between baseline SUA/Cr and incident MetS defined according to the modified criteria of the National Cholesterol Education Program-Adult Treatment Panel III (NCEP ATP III).

RESULTS

One hundred forty-nine (33.3%) men and 286 (45.8%) women had MetS after a 3-year follow-up. Multiple linear regression analysis was performed to evaluate the contribution of possible confounding factors for MetS. In women only, baseline SUA/Cr, as well as baseline number of MetS and age, was significantly and independently associated with the number of MetS components at follow-up. The multivariable-adjusted odds ratios (95% confidence interval) for incident MetS across three quartiles of baseline SUA/Cr (1st-2nd, 3rd, and 4th) were 1.00, 1.62 (0.97-2.69), and 2.07 (1.20-3.56), respectively. Furthermore, when subjects were stratified by age, estimated glomerular filtration rate (eGFR), and presence of baseline MetS, baseline SUA/Cr was also a significant and independent determinant for incident MetS in women with age ≥60 years, eGFR ≥70 mL/min/1.73 m², and presence of baseline MetS.

CONCLUSIONS

Baseline SUA/Cr was significantly associated with incident MetS among community-dwelling women.

Comparison of serum uric acid levels between prostate cancer patients and a control group

Introduction

The aim of this study is to investigate whether the uric acid levels, measured in the serum of patients with a new prostate cancer diagnosis, differ from those in the healthy subjects.

Material and methods

The study included 117 patients who applied to our clinic due to a high prostate specific antigen (PSA) with prostate cancer diagnosis from 2013–2016 and 114 patients applying in the same period for other reasons. The serum uric acid levels and inflammatory markers like c-reactive protein (CRP) and neutrophil count were compared between the groups.

Results

The age distribution of the patients in the prostate cancer and control group was 67.6 ±9.4 and 62 ±8.5 years, respectively. The uric acid levels were identified as 5.05 ±1.14 and 6.04 ±1.12 in the prostate cancer and control group, respectively. Additionally, inflammatory markers like CRP and neutrophil count were identified to be high in the prostate cancer group (p <0.05).

Conclusions

The uric acid levels measured in serum of patients with a prostate cancer diagnosis were reduced compared to the control group and inflammatory markers were found to be increased. Low serum uric acid levels and increased inflammatory markers were determined as risk factors for prostate cancer.

Dietary Magnesium Intake and Hyperuricemia among US Adults

To assess the association between dietary magnesium intake and hyperuricemia in United States (US) adults, we extracted 26,796 US adults aged 20–85 years from the National Health and Nutrition Examination Survey (NHANES) in 2001–2014. All dietary intake was measured through 24 h dietary recall method. Multivariable logistic regression analysis was performed to investigate the association between magnesium intake and hyperuricemia after adjusting for several important confounding variables. When compared to the lowest quintile (Q1), for male, adjusted odds ratios (ORs) of hyperuricemia in the second quintile (Q2) to the fifth quintile (Q5) of the magnesium intake were 0.83 (95% CI: 0.72–0.95), 0.74 (0.64–0.85), 0.78 (0.67–0.90), and 0.70 (0.58–0.84, p for trend = 0.0003), respectively. For female, OR was 0.75 (0.62–0.90) in the fourth quintile (Q4) (p for trend = 0.0242). As compared to Q4 of magnesium intake (contains recommended amount), the relative odds of hyperuricemia were increased by 1.29 times in Q1 (OR = 1.29, 1.11–1.50) in male. The ORs were 1.33 (1.11–1.61) in Q1, 1.27 (1.07–1.50) in Q2 in female. Our results indicated that increased magnesium intake was associated with decreased hyperuricemia risk. It also indicated the importance of recommended dietary allowance (RDA) of magnesium and the potential function of magnesium intake in the prevention of hyperuricemia.

Anti-inflammatory approaches to ischaemic stroke prevention

Stroke is a major cause of neurological morbidity and mortality. Atherosclerosis is a major contributor to first and recurrent stroke. A growing evidence base indicates that inflammation is a key process in the pathogenesis of atherosclerosis, leading to thromboembolic events. In this review, we summarise the evidence linking inflammation to stroke risk and discuss clinical trials addressing the 'inflammation hypothesis' in coronary disease and stroke. Trial registration number CONVINCE trial ClinicalTrials.gov number; NCT 02898610; Pre-results.

The link between insulin resistance parameters and serum uric acid is mediated by adiposity

BACKGROUND AND AIMS

Conflicting results suggest a link between serum uric acid (SUA), inflammation and glucose/insulin homeostasis; however, the role of adiposity in this relationship is not clear. Therefore, we evaluated the role of different adiposity factors, including central body mass index (BMI), peripheral waist circumference (WC), and visceral adiposity [visceral adipose tissue (apVAT)], on the association between SUA, inflammation and glucose/insulin homeostasis among US adults.

METHODS

Data were extracted from the 2005-2010 US National Health and Nutrition Examination Surveys. Overall, 16,502 participants were included in the analysis (mean age = 47.1 years, 48.2% men). Analysis of co-variance and "conceptus causal mediation" models were applied, while accounting for survey design.

RESULTS

Corrected models showed that subjects with higher SUA levels have a less favorable profile of inflammation and glucose/insulin homeostasis parameters (all p < 0.001). We found that all our potential mediators (BMI, WC and apVAT) had an impact (to various extents) on the link between variables, including serum C-reactive protein (CRP), apolipoprotein-B (apoB), insulin resistance markers, 2-h blood glucose (2hG) and triglyceride, and fasting blood glucose (FBG) (TyG) index (all p < .001), while none of the potential mediators (BMI, apVAT, WC) had an impact on the link between FBG and glycated hemoglobin with SUA (all p > 0.05). We have found that all of our mediators partially mediated the link between inflammation and glucose/insulin homeostasis parameters and SUA. Of note, apVAT fully mediated the association between SUA and 2hG.

CONCLUSIONS

By applying advanced statistical techniques, we shed light on the complex link of SUA with inflammation and glucose/insulin homeostasis and quantify the role of adiposity factors in that link.

Association of serum uric acid level with coronary artery stenosis severity in Korean end-stage renal disease patients

Background

Hyperuricemia is common in end-stage renal disease (ESRD) patients, and many previous studies have reported the associations between hyperuricemia and adverse cardiovascular outcomes, which are the major cause of death in such patients. We investigated the relationship between serum uric acid level and the severity of coronary stenosis in ESRD patients on maintenance hemodialysis (MHD).

Methods

Among 721 patients who started MHD treatment, 102 underwent coronary angiographic tests complaining of chest discomfort that was new at initiation of MHD. We collected data on uric acid level and coronary artery luminal diameter, defining luminal diameter narrowing of more than 50% in any major coronary artery as critical-stenosis.

Results

We detected critical coronary artery stenosis in 52 (57.8%) patients. The mean uric acid level was 6.6 ± 2.2 mg/dL, and that was significantly higher in the critical-stenosis group (4.9 ± 1.4 mg/dL vs. 7.8 ± 2.0 mg/dL, P < 0.001). The only independent predictor of critical-stenosis in multivariate analysis was serum uric acid level (P < 0.001).

Conclusion

High serum uric acid was associated with severe coronary artery stenosis in Korean ESRD patients. Hyperuricemia is a readily modifiable factor, and appropriately preventing it could provide significant benefits in ESRD patients.

A double blind placebo controlled randomized trial of the effect of acute uric acid changes on inflammatory markers in humans: A pilot study

Uric acid has been linked with increased risk of chronic disease such as cardiovascular disease and this association has been attributed to a pro-inflammatory effect. Indeed, observational studies have shown that high uric acid is associated with high level of pro-inflammatory cytokines in the blood. However, whether high uric acid directly affects inflammation or rather represents a parallel defensive antioxidant mechanism in response to pathology that causes inflammation is unknown. To determine whether acute increase or decrease uric acid levels affects inflammation in healthy individuals, a randomized, placebo-controlled, double blind clinical study of uric acid or rasburicase with 20 healthy volunteers in each treatment-placebo group was conducted at the National Institute on Aging (NIA) Clinical Research Unit (CRU) at Harbor Hospital in Baltimore, MD. Change in inflammatory response was assessed by administering an oral lipid tolerance before and after the treatment of uric acid, rasburicase and placebo. Following uric acid administration, there was an accentuated increase in IL-6 during the oral lipid tolerance test (P<0.001). No significant differences were observed after lowering of uric acid with rasburicase. No side effects were reported throughout the trial. In health individuals, acute increase in uric acid results in an increased IL-6 response when challenged with lipid load. Such effect of amplification of inflammatory response may explain the higher risk of chronic diseases observed in subclinical hyperuricemia in observational studies.

Trial Registration: ClinicalTrials.gov NCT01323335

Serum uric acid on admission predicts in-hospital mortality in patients with acute coronary syndrome

BACKGROUND

Despite the association between uric acid and cardiovascular disease has been known for decades, the prognostic value of serum uric acid (UA) in all clinical manifestations of acute coronary syndrome (ACS), namely ST-elevation myocardial infarction (STEMI), NSTEMI and unstable angina, has not been definitively assessed.

METHODS

This retrospective analysis included patients from previous SPAI and FAMI studies with the aim to investigate the association between serum uric acid and major adverse cardiovascular events at 180days from hospital admission.

RESULTS

1548 patients were considered and divided in four groups, according UA concentration. Uricemia was significantly associated with gender, BMI, arterial hypertension, HDL-cholesterol, triglycerides, metabolic syndrome and glomerular filtration rate in univariate analysis. Multivariate logistic regression indicated that UA >6.0mg/dL on admission increased the risk of in-hospital mortality in overall population (OR 2.9, 95%CI 1.4-6.1; p=0.0057) and in patients with de novo ACS (OR 3.2, 95%CI 1.5-6.8; p=0.0033). Comparable results were also obtained after adjusting the model for age, gender, body mass index, glomerular filtration rate, metabolic syndrome, acute revascularization and ethnicity. A positive correlation was observed between UA and C reactive protein concentrations in in-hospital deaths only (rho 0.41, p=0.027).

CONCLUSION

In patients with acute coronary syndrome, uricemia levels above the current international reference limit (6.0mg/dl) were associated with in-hospital mortality, independently from ethnicity and renal function.

Association between serum uric acid concentrations and grip strength: Is there effect modification by age?

BACKGROUND

Given that some of the deleterious effects of uric acid (UA) on health are greater in younger than in older subjects, and that age is strongly associated with skeletal muscle composition and function, this study tested the hypothesis that the association between UA and muscle strength differs by age.

METHODS

Cross-sectional analysis with 3595 individuals who participated in NHANES 2011-2012. Serum uric acid was determined by the uricase-peroxidase technique. Grip strength was calculated as the average of the best measure obtained in each hand with a Takei digital grip strength dynamometer. Linear regression models were adjusted for the main confounders.

RESULTS

In individuals aged 20-40 years, the beta coefficients (95% CI) of muscle strength as dependent variable and UA as independent variable comparing the second and third to the lowest tertile of UA were -0.45 kg (-1.46; 0.57) and -2.36 kg (-3.27; -1.44), respectively, p-linear trend ≤0.01. By contrast, in subjects aged 40-60 years the corresponding beta coefficients were 0.21 kg (-1.00; 1.42) and -0.45 kg (-2.10; 1.20), p-linear trend: 0.60; and for subjects ≥60 years they were 0.58 kg (-3.27; 1.65) and 1.57 kg (0.63; 2.50), p-linear trend <0.01. These results held after numerous sensitivity analyses.

CONCLUSION

The association between UA and muscle strength differed depending on age: while a negative link was observed in adults aged 20-40 years, this relationship disappeared later in life, and was reversed after the age of 60. Future research should evaluate if uric acid targets for individuals with hyperuricemia should consider patients age and muscle strength.

Predictive value of serum uric acid in hospitalized adolescents and adults with acute asthma

BACKGROUND

High serum uric acid (sUA) is an indicator of oxidative stress and is linked to tissue hypoxia in asthma. The objective of this case series was to investigate the prognostic role of sUA in patients with acute asthma exacerbations and the link between sUA and spirometric lung tests.

PATIENTS AND METHODS

This cross-sectional observational study included 120 patients with acute asthma exacerbations and 120 controls, categorized according to peak expiratory flow rate into moderate, and severe and life-threatening asthma. On admission, a detailed history was obtained and investigations were carried out regarding oxygen saturation (SaO₂), arterial blood gas, spirometry, sUA, number of asthma exacerbations, smoking status, history of previous hospitalization, intensive care unit admission, and mechanical ventilation.

RESULTS

The current study revealed higher sUA in asthmatic patients compared with healthy subjects and in severe asthma patients compared with moderate asthma patients (P<0.001). A positive correlation of sUA with asthma severity, number of asthma exacerbations and smoking index (r=0.6, 0.42 and 0.29, respectively, P<0.001) and a negative correlation of sUA with SaO₂, partial pressure of arterial oxygen (PaO₂), percent predicted forced vital capacity, percent predicted forced expiratory volume (FEV%) and peak expiratory flow rate percent of predicted (PEFR%; r=-0.48, -0.29, -0.44, -0.44 and -0.66, respectively, P<0.001) were observed. Degree of asthma severity, number of asthma exacerbations, and smoking index were significant predictors of high sUA (R²=0.43, P<0.001) in multiple linear regression model 1. SaO₂ and PEFR% were significant predictors of high uric acid (R²=0.50, P<0.001) in model 2. The sensitivity and specificity of sUA in predicting severity of asthma at the cutoff point of 6.3 mg/dL were 80% and 90%, respectively. The odds ratios of sUA, number of asthma exacerbations, and asthma duration were 5.4, 1.95 and 1.3, respectively.

CONCLUSION

sUA may be a useful marker of predictive value of severity of asthma exacerbations.

Cytokine Profile in Gout: Inflammation Driven by IL-6 and IL-18?

INTRODUCTION

Gout is considered to be an autoinflammatory disease and the presence of monosodium urate (MSU) crystals stimulates activation of NPRL3 inflammasome and subsequently caspase-1, generating production of active IL-1β and IL-18. However, the association between serum cytokines levels and clinical manifestations of the disease is not yet well understood. We evaluated the serum profile of proinflammatory cytokines (IL-1β, IL-6, IL-8, IL-17A, IL-18, IL-22, and IL-23) and described their relationship with clinical and laboratory data.

METHODOLOGY

Thirty-nine male patients with gout (GG) were assessed for clinical and laboratory variables and cytokine levels were measured by ELISA. For the purposes of comparison, 34 males with no previous history of arthritis were also included in the study (CG).

RESULTS

Seventeen participants (43%) exhibited active arthritis on evaluation. Levels of IL-18 were significantly higher in patients in relation to the CG (p = 0.0013). No statistically significant differences were found between the GG and CG for the other measured cytokines. There was a moderate correlation between IL-18 and ESR (R = 0.43, p = 0.0073), CRP (R = 0.47, p = 0.0025), and serum levels of IL-6 (R = 0.36, p = 0.023). An association was observed between serum levels of IL-6 and the presence of tophi (p = 0.005) and deformities (p = 0.0008), as well as a correlation between this cytokine and ESR (R = 0.41, p = 0.011) and CRP (R = 0.48, p = 0.02).

CONCLUSIONS

IL-18 is associated with inflammatory activity in gout, as well as with IL-6 levels, while IL-6 is associated with clinical and laboratory activity, the presence of tophi and articular deformities, and may be a prognostic marker of this pathology.

Serum uric acid and the risk of cardiovascular and renal disease

Substantial evidence suggests that chronic hyperuricemia is an independent risk factor for hypertension, metabolic syndrome, chronic kidney disease (CKD) and cardiovascular diseases. This highlights the need for greater attention to serum uric acid levels when profiling patients, and suggests that the threshold above which uricemia is considered abnormal is 6  mg/dl, in light of the available evidence. Another important question is whether lowering serum uric acid can improve cardiovascular and renal outcomes, and what therapeutic mechanism of action could provide more clinical benefits to patients; the available literature shows a trend toward improvement associated with administration of urate-lowering drugs, in particular for the xanthine oxidase inhibitors. The demonstrated efficacy of urate-lowering therapy on outcomes other than gout flares leads to the consideration that treatment may be beneficial even in the absence of overt gout when hyperuricemia accompanies other clinical conditions, such as urate deposition, advanced CKD or cardiovascular risk factors.

Elevated serum uric acid is associated with vascular inflammation but not coronary artery calcification in the healthy octogenarians: the Brazilian study on healthy aging

BACKGROUND

There is a limited data on the association between serum uric acid (SUA) and cardiovascular disease (CVD) among the very elderly population.

AIMS

We evaluated the association of SUA, highly sensitive C-reactive protein (hs-CRP, a marker of vascular and systemic inflammation), and coronary artery calcification (CAC, a marker of subclinical CVD) in a cohort of Brazilian octogenarians (≥80 years) free from known clinical CVD.

METHODS

208 individuals were included and evaluated for an association between increasing tertiles of SUA, elevated hs-CRP (>3 mg/dL), the presence and burden of CAC (CAC > 0 and CAC > 400).

RESULTS

The median hs-CRP was 1.9 (IQR = 1.0-3.4) mg/L and mean SUA was 5.3 (±1.4) mg/dL. The overall prevalence of elevated hs-CRP (>3 mg/dL) was 31 %. A significant increase in the prevalence of hs-CRP was noted across the higher SUA tertiles (p < 0.001) with 3.4 times the odds of having elevated hs-CRP in the highest SUA tertile (3.40; CI = 1.27-9.08). No association was noted with either the CAC presence and/or CAC burden (CAC > 0 or CAC > 400) across the increasing SUA tertiles.

DISCUSSION

In the healthy octogenarians, higher SUA levels are associated with vascular inflammation (hs-CRP) but not with coronary atherosclerosis (CAC); markers for the subclinical CVD.

The Association Between Hyperuricemia and Hematological Indicators in a Chinese Adult Population

The aim of this study was to explore the relationship between hyperuricemia and hematological indicators. Five hundred twenty-two male and 255 female subjects (18-90 years old) were recruited in the study. The level of serum uric acid (SUA), total white blood cell (WBC) count, red blood cell (RBC) count, hemoglobin, hematocrit, and platelet count was measured, computed, and analyzed. Pearson correlation coefficients, Student t-tests, multivariate linear regression models, and multivariate logistic regression models were performed to analyze the results.For men, WBC count (r = 0.13, P < 0.01), RBC count (r = 0.15, P < 0.001), and hemoglobin (r = 0.11, P < 0.05) were significantly correlated with SUA. For women, WBC count (r = 0.24, P < 0.001), RBC count (r = 0.31, P < 0.001), hemoglobin (r = 0.31, P < 0.001), and hematocrit (r = 0.29, P < 0.001) were significantly correlated with SUA. For men, WBC (P < 0.01) and RBC (P < 0.05) counts were significantly higher in patients with hyperuricemia than in normal subjects. For men, after adjustment for confounding factors, those in the fourth quartiles of WBC counts had 1.66-fold increased odds of hyperuricemia as compared with those in the reference group. For women, after adjustment, those in the second to fourth quartiles of WBC count, RBC count, hemoglobin, and hematocrit had increased the odds of hyperuricemia as compared with those in the reference groups. Our study showed significant relations between the level of SUA and WBC count, RBC count, hemoglobin, and hematocrit, which could be important biological markers of hyperuricemia.

Serum uric acid: a new therapeutic target for nonalcoholic fatty liver disease

INTRODUCTION

Nonalcoholic fatty liver disease (NAFLD) is a major, worldwide public health problem. NAFLD is recognized as a major cause of liver-related morbidity and mortality. However, physicians are currently limited by available treatment options. Recently, numerous studies have reported a correlation between serum uric acid (SUA) and NAFLD with numerous clinical and experimental studies demonstrating a significant correlation. This review will focus on the role of SUA in the development of NAFLD and its potential role as a new target for therapeutic intervention.

AREAS COVERED

This review discusses SUA as a significant independent factor in the development of NAFLD. Moreover, we introduce the causal relationship between SUA, metabolic syndrome, and NAFLD. We discuss two major theories of insulin resistance and inflammasomes as potential explanations of the mechanistic link between SUA and NAFLD. In addition, we review current and emerging therapeutic medications to control appropriate SUA levels.

EXPERT OPINION

There is an urgent need to develop novel, safe and effective therapies for the growing NAFLD epidemic. Reduction of SUA may be a promising potential treatment for patients with NAFLD. Clinical studies are required to determine the therapeutic effect of attenuation of hyperuricemia in humans with NAFLD.

Characteristics of the first metatarsophalangeal joint in gout and asymptomatic hyperuricaemia: a cross-sectional observational study

Background

This study aimed to identify patient-reported outcomes and clinician-assessed characteristics of the first metatarsophalangeal joint (1MTPJ) in people with gout and with asymptomatic hyperuricaemia by comparing them to normouricaemic controls.

Methods

Twenty four people with gout (without current symptoms of acute arthritis), 29 with asymptomatic hyperuricaemia and 34 age- and sex-matched controls participated in this cross-sectional observational study. Patient-reported outcomes included 1MTPJ pain, foot pain and disability, body pain, lower limb function, activity limitation and overall wellbeing. Clinician-assessed characteristics of the 1MTPJ included range of motion (ROM), plantar- and dorsi-flexion force, foot posture, temperature and hallux valgus severity.

Results

Compared to controls, participants with gout reported greater 1MTPJ pain (p = 0.014), greater foot pain and disability (p < 0.001), increased odds of having disabling foot pain (odds ratio (OR) 13.4, p < 0.001), decreased lower limb function for daily living (p = 0.002) and recreational (p < 0.001) activities, increased activity limitation (p = 0.002), reduced overall wellbeing (p = 0.034), reduced ROM (p < 0.001), reduced plantarflexion force (p = 0.012), increased 1MTPJ plantar (p = 0.004), dorsal (p = 0.003) and medial (p = 0.004) temperature and had increased odds of having more severe hallux valgus (OR 0.3 p = 0.041). Compared to controls, participants with asymptomatic hyperuricaemia had increased odds of having disabling foot pain (OR 4.2, p = 0.013), increased activity limitation (p = 0.033), decreased lower limb function for daily living (p = 0.026) and recreational (p = 0.010) activities, increased 1MTPJ plantarflexion force (p = 0.004) and a more pronated foot type (p = 0.036).

Conclusions

People with gout demonstrate 1MTPJ-specific changes indicative of subclinical inflammation, even in the absence of acute arthritis. People with asymptomatic hyperuricaemia, who exhibit no features or symptoms of gout, also report high levels of foot- and lower limb-related pain and disability.

Urate synthesis and oxidative stress in phenytoin hepatotoxicity: the role of antioxidant vitamins

Phenytoin is known to induce microsomal enzymes including xanthine oxidase which catalyzes uric acid synthesis with superoxides as byproducts, thus contributing to the oxidative stress of phenytoin hepatotoxicity. To investigate the role of antioxidant vitamins in ameliorating phenytoin induced hepatic changes through possible actions on xanthine oxidase activities as measured by urate concentration. Growing albino rats of Wistar strain were randomly divided into 8 groups of 7 rats each. Group 2, 3, 4, 5, 6, 7 and 8 were treated with phenytoin alone, phenytoin + folic acid, phenytoin + vitamin E, phenytoin + vitamin E + vitamin C, phenytoin + vitamin C, phenytoin + folic acid + vitamin E and phenytoin + vitamin E + vitamin C + folic acid respectively while animals in group 1 were given normal saline to serve as control. Serum concentrations of uric acid, albumin, total protein and the activities of aspartate and alanine aminotransferases (AST and ALT) and catalase were measured spectrophotometrically using appropriate commercial reagent kits. Result showed that administration of phenytoin alone caused significant (p < 0.05) increase in serum levels of globulin, uric acid, AST and ALT activities while the levels of albumin and catalase were reduced significantly (p < 0.05). Supplementation of phenytoin treatment with vitamins resulted in various degrees of protection. However, the elevated level of uric acid in serum was not significantly (p < 0.05) affected by any of the vitamins used and there was no significant correlation between the activities of aminotransferases and uric acid concentration in the vitamin treated animals as was observed between aminotransferases and catalase. The findings in this study suggest that antioxidant vitamins were able to ameliorate phenytoin hepatotoxic effects by improving oxidant radicals removal in the animals but would not inhibit further generation of the superoxides by xanthine oxidase activity and that xanthine oxidase may contribute significantly to the oxidative stress of phenytoin therapy.

The cross-sectional association between uric acid and atherosclerosis and the role of low-grade inflammation: the CODAM study

OBJECTIVES

The aims of this study were to investigate (i) associations between uric acid and prevalent cardiovascular disease (CVD), ankle-arm blood pressure index (AAIx) and carotid intima-media thickness (CIMT) in the total population and in predefined subgroups according to glucose metabolism status and (ii) the extent to which these associations are explained by low-grade inflammation.

METHODS

Cross-sectional analyses were conducted among 530 individuals [60.6% men, mean age 58.9 years (s.d. 6.9), 52.6% normal glucose metabolism (NGM)] at increased risk of CVD from the Cohort of Diabetes and Atherosclerosis Maastricht study. A low-grade inflammation score was computed by averaging the z-scores of eight inflammation markers [CRP, TNF-α, IL-6, IL-8, serum amyloid A, intercellular adhesion molecule 1 (ICAM-1), ceruloplasmin and haptoglobin].

RESULTS

After adjustment for traditional CVD risk factors, plasma uric acid (per s.d. of 81 μmol/l) was associated with CVD in individuals with NGM [odds ratio (OR) = 1.66, 95% CI 1.06, 2.58] but not with disturbed glucose metabolism (DGM) (OR = 0.81, 95% CI 0.55, 1.19, P interaction = 0.165). Uric acid was associated with CIMT in the total population (β = 0.024, 95% CI 0.007, 0.042) and slightly more strongly in individuals with NGM (β = 0.030, 95% CI 0.006, 0.054) than DGM (β = 0.018, 95% CI -0.009, 0.044, P interaction = 0.443). There was no association between uric acid and AAIx in any group (P interaction = 0.058). Uric acid was associated with low-grade inflammation in the total population (β = 0.074, 95% CI 0.013, 0.134, P interaction = 0.737). Adding low-grade inflammation to the models did not attenuate any of the associations.

CONCLUSION

The associations for uric acid with CIMT, and with CVD in NGM only, were not explained by low-grade inflammation. A difference in the strength of the associations between individuals with NGM and DGM was suggested.

Interaction of inflammation, hyperuricemia, and the prevalence of hypertension among adults free of metabolic syndrome: NHANES 2009-2010

Background

Hyperuricemia and markers of inflammation are correlated with the risk for hypertension. Whether hyperuricemia has any impact on the association between C‐reactive protein (CRP) and hypertension is not known.

Methods and Results

We analyzed cross‐sectional data from the National Health and Nutrition Examination Survey, 2009–2010, using ordinary least squares and logistic regression models. Those who met the criteria for metabolic syndrome, had self‐reported gout, or were <20 years old were excluded. For each 1‐SD increase in serum urate, the serum CRP concentration was 20% higher in unadjusted linear regression models and 13% higher in multivariable linear regression models, after accounting for the effects of age, sex, race, socioeconomic and educational strata, renal function, lipids, smoking, and body mass index. In multivariable models adjusting for the same covariates, hyperuricemia was associated with hypertension with an odds ratio of 2.21 (1.71 to 2.85). When analyzed separately, this was observed in men and women. In multivariable analyses of the overall sample, elevated CRP levels were not associated with hypertension.

Conclusions

Among adults free of metabolic syndrome, elevated uric acid, but not elevated CRP, is independently associated with prevalent hypertension.

Review of hyperuricemia as new marker for metabolic syndrome

Hyperuricemia has long been established as the major etiologic factor in gout. In recent years, a large body of evidence has accumulated that suggests that hyperuricemia may play a role in the development and pathogenesis of a number of metabolic, hemodynamic, and systemic pathologic diseases, including metabolic syndrome, hypertension, stroke, and atherosclerosis. A number of epidemiologic studies have linked hyperuricemia with each of these disorders. In some studies, therapies that lower uric acid may prevent or improve certain components of the metabolic syndrome. There is an association between uric acid and the development of systemic lupus erythematosus; the connection between other rheumatic diseases such as rheumatoid arthritis and osteoarthritis is less clear. The mechanism for the role of uric acid in disorders other than gout is not well established but recent investigations point towards systemic inflammation induced by urate, as the major pathophysiological event common to systemic diseases, including atherosclerosis.

Uric acid levels in obstructive sleep apnea patients with atrial fibrillation

BACKGROUND AND AIMS

The objective of this observational study was to determine whether there is an association between atrial fibrillation (AF) and uric acid and to identify the risk markers for AF in obstructive sleep apnea (OSA).

METHODS

Consecutive patients with newly diagnosed OSA were screened at baseline. The final study population consisted of 516 patients. One hundred and eight patients had AF. Demographic, clinical, laboratory, and echocardiographic characteristics were carefully recorded. Logistic regression was used for the multivariate analysis of independent risk factors.

RESULTS

Uric acid, triglyceride, high-density lipoprotein, C-reactive protein (CRP), left atrial diameter, interventricular septum thickness, apnea hypopnea index, and Epworth sleepiness scale were significantly higher in OSA patients with AF than in those without AF (p <0.05). Among these patients, multiple logistic analyses indicated the independent risk factors for AF occurrence in the OSA subjects included serum uric acid level, left atrial diameter, percentage of time with SaO2 <90%, CRP. The diagnosis analysis showed that higher uric acid, CRP, left atrial diameter and percentage of time with SaO2 <90% had a significant ability to reflect the presence of AF occurrence.

CONCLUSIONS

The novel finding of this study is that the occurrence of AF in OSA patients is strongly related to serum uric acid level, left atrial diameter, percentage of time with SaO2 <90% and CRP level. These results may be helpful for monitoring AF occurrence in OSA patients.

Sugar, uric acid, and the etiology of diabetes and obesity

The intake of added sugars, such as from table sugar (sucrose) and high-fructose corn syrup has increased dramatically in the last hundred years and correlates closely with the rise in obesity, metabolic syndrome, and diabetes. Fructose is a major component of added sugars and is distinct from other sugars in its ability to cause intracellular ATP depletion, nucleotide turnover, and the generation of uric acid. In this article, we revisit the hypothesis that it is this unique aspect of fructose metabolism that accounts for why fructose intake increases the risk for metabolic syndrome. Recent studies show that fructose-induced uric acid generation causes mitochondrial oxidative stress that stimulates fat accumulation independent of excessive caloric intake. These studies challenge the long-standing dogma that "a calorie is just a calorie" and suggest that the metabolic effects of food may matter as much as its energy content. The discovery that fructose-mediated generation of uric acid may have a causal role in diabetes and obesity provides new insights into pathogenesis and therapies for this important disease.

Plateletcrit. A platelet marker associated with saphenous vein graft disease

BACKGROUND

Saphenous vein graft disease (SVGD) after by-pass surgery is an important cause of morbidity and mortality for patients with coronary artery disease. Comprehensive evaluation of biochemical and hematological parameters associated with this problem is limited. Plateletcrit (PCT) provides complete information on total platelet mass, but it has not been previously studied. In this study, we examined the relationship between SVGD and platelet parameters such as PCT, mean platelet volume, platelet count, and platelet distribution.

METHODS

We retrospectively analyzed 14,398 patients who underwent coronary angiography between February 2006 and August 2012. Records from 893 patients with previous coronary artery by-pass graft operation were re-evaluated. A total of 251 cases were divided into two groups (127 patients receiving a saphenous vein graft; 124 patients diagnosed with SVGD) and hematological and biochemical parameters were compared.

RESULTS

There were no significant differences in clinical characteristics between the two groups except that the SVGD group had a higher median time from surgery to coronary angiography than the patent saphenous vein graft group [7 years (2-16) vs. 5 years (2-15), p < 0.001]. The SVGD groups also had significantly higher median PCT, mean platelet volume, platelet count, uric acid level, and red blood cell distribution width. The cut-off value for PCT was found to be 0.188 for predicting SVGD, with an 80.65 % sensitivity and 81.1 % specificity.

CONCLUSION

Plateletcrit has an important predictive value for SVGD, and it could be used as a marker for anti-platelet therapy to prevent graft atherosclerosis in patients undergoing by-pass surgery.