Asymptomatic hyperuricemia is not an independent risk factor for cardiovascular events or overall mortality in the general population of the Busselton Health Study

U-shaped association of serum uric acid with cardiovascular disease risk scores and the modifying role of sex among Chinese adults

BACKGROUND AND AIMS

Serum uric acid (SUA) is involved in the development of cardiovascular disease (CVD). However, information on the dose-response relationship between SUA and CVD is limited in the Chinese population. This study aimed to investigate the potential nonlinear dose-response association of SUA with CVD risk in a Chinese population and to explore the effect of sex on these associations.

METHODS AND RESULTS

Cross-sectional data, from 6252 Chinese adults aged 30-74 years who participated in the China Health and Nutrition Survey 2009, were stratified by SUA deciles. The 10-year risk of CVD was determined using the Framingham risk score. A restricted cubic spline (RCS) was incorporated into the logistic models to assess the nonlinear relationship between SUA and CVD. Among the participants, 65%, 20%, and 15% had low, moderate, and high 10-year CVD risks, respectively. Compared with the reference SUA strata of 225 to <249 μmol/L, CVD risk was significantly increased at SUA ≥294 μmol/L, with adjusted ORs ranging from 2.39 (1.33-4.33) to 4.25 (2.37-7.65). An increasingly higher nonsignificant CVD risk was found at SUA <225 μmol/L and showed a nonlinear U-shaped association. In the fitted RCS model, an approximate U-shaped association between SUA and CVD risk scores was found in women, but this significant nonlinear relationship was not found in men.

CONCLUSION

This study showed that both lower and higher SUA levels were associated with a higher 10-year CVD risk among Chinese adults, forming a U-shaped relationship, and this pattern was particularly pronounced for women.

A Hospital-Based Cross-Sectional Study of Patients With Plantar Fasciitis: Is Hyperuricemia Screening Needed?

Background and aim Generally, asymptomatic hyperuricemia is considered a benign metabolic abnormality with little clinical significance in the absence of gout or renal calculus. However, its clinical association with plantar fasciitis is still not known and is a subject of interest. The study aims to investigate the association between asymptomatic hyperuricemia and plantar fasciitis in otherwise healthy patients. Materials and methods A cross-sectional study was performed, which included 284 patients aged 21-65 years with plantar fasciitis and without any comorbidities between February 2020 and November 2022. One hundred and fifty patients with hyperuricemia who attended the endocrinology and medicine outpatient department without heel pain were included as a control group. Serum uric acid levels were assessed in all cases. Student's t-test, correlation tests, and multiple linear regression were used to ascertain the association between uric acid levels and plantar fasciitis. Statistical analyses were conducted using IBM SPSS Statistics for Windows, Version 19.0 (Released 2010; IBM Corp., Armonk, New York, United States). Results Among the 284 patients, 189 were female (66.5%) and 95 were male (33.4%). Their mean age was 43 ± 9 years (range: 21-65 years). The p-values of the duration of symptoms, visual analog scale for pain (VAS), and foot function index (FFI) total score were p = 0.061, p = 0.068, and p < 0.001, respectively. The mean uric acid levels were 7.6 ± 1.5 mg/dL in males and 7.3 ± 1.3 mg/dL in females in the sample group, and 8.3 ± 1.8 mg/dL in males and 8.1 ± 1.5 mg/dL in females in the control group. According to a Pearson correlation analysis, there was no correlation between serum uric acid level and BMI, VAS, duration of symptoms, FFI pain, disability sub-scores, or FFI total score. Conclusion Although asymptomatic hyperuricemia is a common metabolic abnormality, the present study did not find any significant association between it and plantar fasciitis. Therefore, we can conclude that routine screening for asymptomatic hyperuricemia is not recommended in plantar fasciitis. Evidence level: II.

Gout Screening Identifies a Large Cardiovascular Population at Increased Risk of Mortality

OBJECTIVE

Gout is prevalent in people with cardiovascular disease, although up to a third of the cases remain unregistered. We aimed to assess whether active gout screening in inpatients with cardiovascular events helps identify patients at higher risk of mortality after discharge.

METHODS

This study included patients admitted for cardiovascular events. Gout was established by records review and clinical interview. After discharge, electronic medical records were reviewed for mortality and cause of death. The association between gout and subsequent mortality was tested using Cox regression models.

RESULTS

Of 266 recruited patients, 17 were lost to follow-up, leaving a final sample of 249 patients (93.6%). Thirty-six cases (14.5%) were classified as having gout; 13 of these (36.1%) were identified through the interview. Mean follow-up was 19.9 (SD, 8.6) months. Gout significantly increased the risk of all-cause mortality in the overall sample (hazard ratio [HR], 2.01; 95% confidence interval [CI], 1.13-3.58) and in the subgroup with a prior diagnosis of gout (HR, 2.89; 95% CI, 1.54-5.41). The adjusted HR for all-cause mortality associated with gout was 1.86 (95% CI, 1.01-3.41). Patients with gout carried an increased risk of both cardiovascular and noncardiovascular deaths; age and chronic kidney disease were mortality predictors within the gout population.

CONCLUSION

Gout was an independent predictor of subsequent all-cause mortality in patients admitted for cardiovascular events. Active screening for gout allowed the detection of a larger population at high risk of mortality and could help tailor patient management to minimize the cardiovascular impact.

Association between hyperuricemia and hypertension: a case-control study

OBJECTIVE

The aim of this study was to evaluate the association between hyperuricemia and systemic arterial hypertension.

METHODS

This was a case-control study where individuals aged >18 years were included, who were divided into hypertensive and non-hypertensive groups, excluding those with incomplete information in medical records or with the chronic kidney disease epidemiology collaboration <60 mL/min/1.73 m³. Systemic arterial hypertension was categorized as a dependent variable, while the independent variables were hyperuricemia (i.e., primary variable), sex, education, the practice of physical activity, alcoholism, smoking, diabetes mellitus, chronic kidney disease, a family history of systemic arterial hypertension, age, isolated hyperlipidemia, and mixed hyperlipidemia. Statistical analysis included the univariate and multivariate data analysis, performed by adjusting the logistic regression models using the software R (R Core Team [2018]).

RESULTS

Out of 103 patients evaluated, 75 patients were included in this study. In hypertensive patients, hyperuricemia was more frequent (p=0.029), being present in 18.9% individuals. In the univariate analysis, a statistically significant association was found between hyperuricemia and systemic arterial hypertension (OR 10.9; 95%CI 1.29-1420.0; p=0.023); however, in the multivariate analysis, when adjustment was made for age, the only control variable that persisted in the model, this association ceased to be significant (OR 8.5; 95%CI 0.87-1157.0; p=0.070).

CONCLUSIONS

There was no independent association between hyperuricemia and systemic arterial hypertension. The latter was associated with diabetes mellitus, chronic kidney disease, and age.

Longitudinal development of incident gout from low-normal baseline serum urate concentrations: individual participant data analysis

INTRODUCTION

Elevated serum urate (SU) concentration is the central risk factor for the development of gout. The aim of this study was to examine the incidence of gout in people with low and normal SU levels (< 7.00 mg/dL).

METHODS

Longitudinal cohort data from the Atherosclerosis Risk in Communities Study (ARIC), Coronary Artery Risk Development in Young Adults Study (CARDIA), and both the Original and Offspring cohorts of the Framingham Heart Study (FHS) were used to determine incident gout by baseline SU over 3, 5, 10, 12 and 15 year periods. A Cox proportional hazards model with covariables of age, gender, ethnicity, and cohort was calculated to report the hazard ratios (HR) for incident gout.

RESULTS

The incidence of gout at 15 years for a baseline SU < 4.00 mg/dL was 0.59%, 4.00-4.49 mg/dL was 1.28%, 4.50-4.99 mg/dL was 0.86%, 5.00-5.49 mg/dL was 0.94%, 5.50-5.99 mg/dL was 1.52%, 6.00-6.49 mg/dL was 2.91%, 6.50-6.99 mg/dL was 3.2%, and > 7.00 mg/dL was 12.2%. In an adjusted Cox proportional hazards model, compared to the referent baseline SU < 4.00 mg/dL, there was a non-significant increase in incident gout for baseline SU bands between 4.00-5.49 mg/dL, whereas incident gout was significantly increased for SU 5.50-5.99 mg/dL (HR 2.60), 6.00-6.49 mg/dL (HR 3.70), 6.50-6.99 mg/dL (HR 5.24) and > 7.00 mg/dL (HR 18.62).

CONCLUSION

A baseline SU of 5.50 mg/dL or more is a risk factor for development of gout over 15 years. However, incident gout does occur over time in a small proportion of people with lower baseline SU levels.

The prevalence of gout and hyperuricaemia in Australia: An updated systematic review

BACKGROUND

Gout continues to increase in prevalence in developed countries with Oceanic countries particularly affected. Both gout and hyperuricaemia are associated with the metabolic syndrome and its sequelae. Recently, the Australian Institute for Health and Welfare (AIHW) reported a prevalence rate of 0.8% which appeared incongruous with other published research. Thus, an updated systematic review was undertaken to review the literature on the prevalence of gout and hyperuricaemia in Australia from data published after 2011.

METHODS

A comprehensive, systematic search was conducted in MEDLINE, Embase and Web of Science in addition to relevant websites to identify research reporting the prevalence of gout and/or hyperuricaemia in Australia from May 2011 until June 2020. Crude gout and hyperuricaemia prevalence data was obtained and presented alongside case ascertainment, time-period, age range and stratified by gender if available.

RESULTS

118 full text articles were screened. 12 articles were included for analysis of gout prevalence. 4 articles were identified for the hyperuricaemia analysis. Wide variation in prevalence figures exist largely due study design and sample age range. Studies using a case definition of self-reported diagnosis of gout reported prevalence rates between 4.5% and 6.8%. The remaining studies used either electronic coding data from general practitioners or wastewater estimation of allopurinol consumption and documented adult prevalence rates between 1.5% and 2.9%. Prevalence increases with age, male sex and over time in keeping with global data. Hyperuricaemia prevalence ranged between 10.5% and 16.6% in Caucasian or an Australian representative population. AIHW estimates applied a chronic condition status, defined as current and lasted or expected to last more than six months, to cases of gout in the Australian National Health Survey. This likely results in an under-estimation in reported Australian gout prevalence rates.

CONCLUSIONS

Gout is highly prevalent in Australia compared to global comparisons and continues to increase over time. Hyperuricaemia prevalence is also high although contemporary data is limited.

Gout Is Prevalent but Under-Registered Among Patients With Cardiovascular Events: A Field Study

Objectives: Gout is an independent cardiovascular (CV) risk factor with significant morbidity and mortality. We aimed to estimate the prevalence of gout, characteristics and management in a hospitalized population for CV disease, a topic that remains to be defined. Methods: An observational, descriptive, cross-sectional study was carried out in patients admitted for CV events in the Cardiology, Neurology, and Vascular Surgery units of a tertiary center. Patients were selected following a non-consecutive, systematic sampling. Data about CV disease and gout were obtained from face-to-face interviews and patients' records. Gout diagnosis was established using the 2015 ACR/EULAR clinical classification criteria. The registration rate of gout was assessed by auditing patients' records and hospital discharge reports of CV events from the units of interest in the previous 2 years. To predict the presence of gout, multivariate logistic regression models were built to study the possible explanatory variables. Results: Two hundred and sixty six participants were recruited, predominantly males (69.9%) and Caucasians (96.6%) with a mean age of 68 years. Gout was identified in 40 individuals; thus, the prevalence was 15.0% (95% CI 10.9-19.2%). In 35% of cases, the diagnosis was absent from patients' records. Gout was found in 1.4-2.6% of hospital discharge reports of CV events, also indicating under-registration. The disease was long-standing, but with low reported rates of flares, involved joints, and tophi. At admission, only half of the gout patients were on urate-lowering therapy, being 38.5% of them on serum urate <6 mg/dl. The only independent predictor of gout was the existence of previous hyperuricemia (median serum urate in previous 5 years ≥7 mg/dl), with an odds ratio of 2.9 (95% CI 1.2-7.1); if hyperuricemia is not included in the model, the only independent predictor was chronic kidney disease (odds ratio 3.0; 95% CI 1.4-6.6). Conclusion: Gout is highly prevalent among patients admitted for CV events, with significant lack of awareness and suboptimal management, despite being a well-established independent CV risk factor.

Repeated measurements of serum urate and mortality: a prospective cohort study of 152,358 individuals over 8 years of follow-up

BACKGROUND

Longitudinal evidence on change of serum urate level with mortality risk is limited as prior studies have a measurement of serum urate at a single time point. Further, the combined effect of serum urate and systemic inflammation on mortality is unknown.

METHODS

We conducted a prospective cohort study of 152,358 participants (122,045 men and 30,313 women) with repeated measurements of serum urate in 2006, 2008, 2010, and 2012 (107,751 participants had all four measurements of serum urate). We used the Cox proportional hazard model to examine the association between cumulative average and changes in serum urate with mortality. The combined effect of serum urate and systemic inflammation was determined by testing the interaction of serum urate and high-sensitive C-reactive protein (hs-CRP) in relation to mortality risk.

RESULTS

During a median follow-up of 8.7 (interquartile range 6.3-9.2) years, we identified 7564 all-cause deaths, 1763 CVD deaths, 1706 cancer deaths, and 1572 other deaths. We observed U-shaped relationships of cumulative average serum urate with all-cause mortality, cardiovascular mortality, and other mortalities. Compared with participants with stable serum urate, those with greater increases in serum urate had a 1.7-fold elevated mortality (hazard ratio (HR) = 1.66, 95% confidence interval (CI) = 1.49-1.84), and those with decreased serum urate had a 2-fold elevated mortality risk (HR = 2.14, 95% CI 1.93-2.37). Participants with both hyperuricemia and hs-CRP had 1.6 times higher mortality, compared with those with low serum urate and hs-CRP levels (HR = 1.56, 95% CI 1.37-1.76).

CONCLUSIONS

We observed a U-shaped relationship of long-term cumulative average serum urate with all-cause mortality, cardiovascular mortality, and other mortalities. Compared with participants with relatively stable serum urate levels, a greater increase or decrease in serum urate was associated with elevated mortality. Participants with both hyperuricemia and high systemic inflammation had the greatest mortality risk compared with those with low serum urate and low hs-CRP levels.

Association Between the Serum Uric Acid Level and the Severity of Coronary Artery Disease in a Retrospective Study of China Nondialysis CKD Patients

Introduction: Hyperuricemia has been associated with increased cardiovascular events in the general population. However, the role of serum uric acid (SUA) level on the severity of coronary artery stenosis (CAS) in nondialysis chronic kidney disease (CKD) patients is obscure. Methods: We implement a retrospective cohort study of 734 patients diagnosed with stage 3-5 CKD. All selected patients underwent coronary artery angiography. The associations of SUA with the present, and severity of coronary artery disease (CAD) were analyzed. Results: Of these 734 patients, 511 patients had angiographically proven CAD. Compared with non-CAD group, the SUA level in CAD group was much higher (388.00 vs. 363.00 μmol/l, P < 0.01). After adjusting for multiple confounding factors, a multivariate logistic regression analysis demonstrated that SUA was relevant to the presence of CAD when SUA as a continuous variable. However, this relationship was not observed with SUA as a categorical variable. In a subgroup analysis for the CAD group, we found that the rates of severe CAS in the third tertile of SUA (58.6%) was higher than that in the first tertile (41.6%) (P < 0.01). Compared with the first tertile of SUA, the third tertile of SUA was an independent risk factor for severe arterial stenosis (odds ratio, OR, 1.976 [1.203-3.248]), a pattern that was recapitulated by multivariate logistic regression analysis with SUA as a continuous variable (1.002 [1.000-1.004]). Conclusions: The SUA level may serve as a predictor of the severity of CAS among nondialysis CKD patients with CAD.

Serum uric acid and risk of cardiovascular mortality: a systematic review and dose-response meta-analysis of cohort studies of over a million participants

Background

Cardiovascular disease (CVD) is the leading cause of death worldwide. Some studies have suggested anassociation between serum uric acid levels and cardiovascular mortality; however, the results have not been summarized in a meta-analysis.

Methods

A comprehensive search of all related studies until April 2018was performed in MEDLINE/PubMed and Scopus databases DerSimonianand Laird random-effects models were used to combine hazard ratios (HRs) with 95% confidence intervals (CIs). Dose-response analysis was also carried out.

Results

Thirty-two studies containing forty-four arms with 1,134,073 participants reported association between uric acid and risk of CVD mortality were included in our analysis. Pooled results showed a significant positive association between uric acid levels and risk of CVD mortality (HR 1.45, 95% CI 1.33–1.58, I² = 79%). Sub-group analysis showed this relationshipwasstronger in women compared to men. Moreover, there was a significant non-linear association between uric acid levels and the risk of CVD mortality (r = 0.0709, p = 0.001).

Conclusion

Our analysis indicates a positive dose-response association between SUA and CVD mortality risk.

Ultrasonographic assessment of joint pathology in type 2 diabetes and hyperuricemia: The Fremantle Diabetes Study Phase II

AIMS

The prevalence and consequences (articular and extra-articular) of hyperuricemia in type 2 diabetes, especially when asymptomatic (ASH), are incompletely understood. The aim of this study was to use ultrasonography to assess pathology associated with monosodium urate deposition in the joints of well-characterized hyperuricemic patients with type 2 diabetes.

METHODS

A subset of 101 participants (mean age 70.4 years, 59.8% males, median diabetes duration 14.6 years) with hyperuricemia (fasting serum uric acid ≥0.42 mmol/L) from the community-based observational Fremantle Diabetes Study Phase II were assessed by ultrasound for signs of intra-articular urate deposition and inflammation in 14 joints at increased risk of involvement in patients with gout.

RESULTS

Most participants had evidence of crystal deposition comprising aggregates (59.4%), tophi (19.8%) or a double contour sign (27.7%), and 37% had a power Doppler signal indicative of inflammation in at least one joint. There was no difference between the prevalence of these abnormalities in those with ASH (n = 60) versus participants with a history of gout (n = 41; P ≥ 0.15). There was no association between a history of ischemic heart disease (reported by 17.8% of participants) and either any abnormality on joint ultrasound or inflammatory changes assessed by power Doppler (P ≥ 0.41).

CONCLUSIONS

Joint inflammation and/or urate deposition were present in the majority of community-based patients with type 2 diabetes and hyperuricemia regardless of whether there was a history of gout. Given the potential consequences of chronic inflammation for joint damage and extra-articular complications such as cardiovascular disease, these data have potential clinical implications.

Elevated serum uric acid levels are associated with endothelial dysfunction in HIV patients receiving highly-active antiretroviral therapy

BACKGROUND AND AIMS

Elevated serum uric acid (SUA) levels may be associated with endothelial dysfunction. Increased rates of metabolic syndrome (MS) and elevated SUA levels were described in human immunodeficiency virus (HIV) infected patients. We investigated whether SUA levels are associated with endothelial dysfunction in HIV positive patients receiving highly-active antiretroviral therapy (HAART) irrespective of MS.

METHODS

In this cross-sectional study of 250 HIV positive patients receiving stable HAART, we evaluated the relationship between MS, SUA levels and endothelial function. SUA levels and brachial artery flow-mediated dilation (bFMD) were measured. The relationship between logarithmic (LG)-transformed SUA levels and bFMD was evaluated after correction for MS.

RESULTS

MS was detected in 28.4% of patients and elevated SUA levels (≥6 mg/dL) in 25.2%. MS was associated with higher LG-SUA levels (age-, gender- and glomerular filtration rate-adjusted beta = 0.204, p = 0.001). The crude linear association between LG-SUA levels and LG-bFMD (beta = -0.166, p = 0.008) was abolished after correction for MS (beta = -0.089, p = 0.172). When SUA levels were used as a categorical variable (≥6 mg/dL or <6 mg/dL and SUA quartiles, respectively), the association between LG-SUA levels and LG-bFMD remained significant after adjustment for MS (beta = -0.142, p = 0.022 and beta = -0.163, p = 0.010, respectively).

CONCLUSIONS

MS significantly affects SUA levels in HAART-treated HIV infected patients. The negative association between SUA and bFMD is independent of MS only for elevated SUA levels.

The problem of cardio-renal diseases in patients with gout

BACKGROUNDS

Although evidence is mounting on the role of hyperuricemia in cardio-renal disease, continuing doubt remains as to whether hyperuricemia can be considered a major causal cardiovascular risk factor. In addition, available data suggest that treatment may be beneficial, even in the absence of overt gout, when hyperuricemia accompanies other clinical conditions, such as urate deposition, advanced chronic kidney disease, or cardiovascular risk factors.

METHODS AND RESULTS

Analysis of the literature suggests there would be sufficient evidence warranting clinical trials to determine whether lowering uric acid levels would be clinically beneficial in the prevention or treatment of cardiovascular and renal diseases.

CONCLUSION

Under a practical profile, it becomes progressively more important to investigate the possibility of reducing serum uric acid levels in the general population below the level of 5.0 mg/dL.

Relationship between plasma xanthine oxidoreductase activity and left ventricular ejection fraction and hypertrophy among cardiac patients

Background and purpose

Xanthine oxidoreductase (XOR), which catalyzes purine catabolism, has two interconvertible forms, xanthine dehydrogenase and xanthine oxidase, the latter of which produces superoxide during uric acid (UA) synthesis. An association between plasma XOR activity and cardiovascular and renal outcomes has been previously suggested. We investigated the potential association between cardiac parameters and plasma XOR activity among cardiology patients.

Methods and results

Plasma XOR activity was measured by [¹³C₂,¹⁵N₂]xanthine coupled with liquid chromatography/triplequadrupole mass spectrometry. Among 270 patients who were not taking UA-lowering drugs, XOR activity was associated with body mass index (BMI), alanine aminotransferase (ALT), HbA1c and renal function. Although XOR activity was not associated with serum UA overall, patients with chronic kidney disease (CKD), those with higher XOR activity had higher serum UA among patients without CKD. Compared with patients with the lowest XOR activity quartile, those with higher three XOR activity quartiles more frequently had left ventricular hypertrophy. In addition, plasma XOR activity showed a U-shaped association with low left ventricular ejection fraction (LVEF) and increased plasma B-type natriuretic peptide (BNP) levels, and these associations were independent of age, gender, BMI, ALT, HbA1C, serum UA, and CKD stages.

Conclusions

Among cardiac patients, left ventricular hypertrophy, low LVEF, and increased BNP were significantly associated with plasma XOR activity independent of various confounding factors. Whether pharmaceutical modification of plasma XOR activity might inhibit cardiac remodeling and improve cardiovascular outcome should be investigated in future studies.