The relationship between elevated serum uric acid and arterial stiffness in a healthy population

High serum uric acid is a risk factor for arterial stiffness in a Chinese hypertensive population: a cohort study

The prospective cohort study was to explore the association between serum uric acid (SUA) and arterial stiffness in a Chinese hypertensive population. A total of 7444 participants with hypertension who completed two or more measurements of brachial-ankle pulse wave velocity (baPWV) and baseline SUA detection were followed-up in the Kailuan Study from 2010 to 2020. A restricted cubic spline curve was used to verify whether there was a linear association between baseline SUA and arterial stiffness. A Cox proportional hazard regression model was used to explore the association of between baseline SUA and the incidence of arterial stiffness. Our results showed that the restricted cubic spline curve revealed a linear relationship between baseline SUA and arterial stiffness in total participants (p < 0.001). After follow-up 4.6 ± 2.8 years, Kaplan-Meier survival curves indicated that the risk of arterial stiffness was increased in the high level of baseline SUA (Log-rank p = 0.0002). After adjusting for potential confounding factors, the HR (95% CI) for risk of stiffness was 1.33 (1.17-1.52, p < 0.001) in the highest SUA group. Hierarchical analysis showed that the HRs (95% CI) for risk of arterial stiffness were 1.45 (1.25-1.69), 1.38 (1.19-1.60), 1.41 (1.21-1.64), and 1.35 (1.15-1.58) in the highest SUA group of males, <65 years old, not taking antihypertensive drugs, and failure to achieve the control targets of blood pressure respectively (p < 0.001). These results reveal that high SUA is a risk factor for arterial stiffness in the Chinese hypertensive population.

A Mendelian randomization study of serum uric acid with the risk of venous thromboembolism

BACKGROUND

Observational studies have linked hyperuricemia with venous thromboembolism (VTE). We aimed to investigate whether there are causal relationships between uric acid levels and VTE and its subtypes, including deep venous thrombosis (DVT) of the lower extremities and pulmonary embolism (PE).

METHODS

We utilized Mendelian randomization (MR) analysis to estimate the causal association in European individuals. We extracted two sets of polygenic instruments strongly associated (p < 5 × 10^-8) with uric acid from the CKDGen consortium and UK biobank, respectively. Genetic associations with the risk of VTE, DVT, and PE were obtained from the FinnGen biobank. We used the inverse-variance weighted method as the preliminary estimate. Additionally, we employed MR-Egger, weighted median, and Mendelian randomization pleiotropy residual sum and outlier method as complementary assessments. Sensitivity analyses were performed to test for pleiotropic bias.

RESULTS

The genetically instrumented serum uric acid levels had no causal effects on VTE, DVT, and PE. Two sets of polygenic instruments used for exposure, along with three complementary MR methods, also yielded no significant association.

CONCLUSIONS

Our MR analysis provided no compelling evidence for a causal relationship of serum uric acid with the risk of VTE. This suggests that uric acid-lowering therapies in patients with hyperuricemia may not be effective in reducing the likelihood of developing VTE.

Comparative Evaluation of Orthostatic Hypotension in Patients with Diabetic Nephropathy

INTRODUCTION

Orthostatic hypotension (OH) affects 5-20% of the population. Our study investigates the presence of OH in diabetic nephropathy (DNP) patients and the factors affecting OH in comparison with nondiabetic chronic kidney disease (NDCKD) patients.

METHOD

Patients presented to the nephrology clinic, and those who consented were included in the study. DNP was defined by kidney biopsy and/or clinical criteria. NDCKD patients of the same sex, age, and eGFR were matched to DNP patients. Demographic parameters and medications were obtained from the records. OH was determined by Mayo clinic criteria. The same researcher used an electronic device to measure blood pressure (BP). All samples were taken and analyzed the same day for biochemical and hematologic parameters and albuminuria.

RESULTS

112 (51 F, 61 M, mean age: 62.56 ± 9.35 years) DNP and 94 (40 F, 54 M, mean age: 62.23 ± 10.08 years) NDCKD patients were included. There was no significant difference between DNP and NDCKD groups in terms of OH prevalence (70.5 vs. 61.7%, p = 0.181). Male patients had significantly higher OH prevalence than female patients (74.7 vs. 60.0%, p = 0.026). There was no significant difference in change in systolic BP between the groups (24.00 [10.00-32.00] mm Hg vs. 24.00 [13.75-30.25] mm Hg, p = 0.797), but the change in diastolic BP was significantly higher in the DNP group (8.00 [2.00-13.00] mm Hg vs. 6.00 [2.00-9.00] mm Hg, p = 0.025). In the DNP group, patients with OH had significantly higher uric acid levels than those without OH (7.18 ± 1.55 vs. 6.36 ± 1.65 mg/dL, p = 0.017). And, 73.7% of patients on calcium channel blockers developed OH (p = 0.015), and OH developed in 80.6% of 36 patients on alpha-blockers (p = 0.049).

CONCLUSION

OH prevalence is very high in CKD, and etiology of CKD does not have a statistically significant effect on the frequency of OH, despite a difference that could be meaningful clinically. Therefore, patients with CKD are checked for OH, with or without concurrent diabetes mellitus. Evaluation of postural BP changes should be a part of nephrology practice.

The Role of ABCG2 in the Pathogenesis of Primary Hyperuricemia and Gout-An Update

Urate homeostasis in humans is a complex and highly heritable process that involves i.e., metabolic urate biosynthesis, renal urate reabsorption, as well as renal and extrarenal urate excretion. Importantly, disturbances in urate excretion are a common cause of hyperuricemia and gout. The majority of urate is eliminated by glomerular filtration in the kidney followed by an, as yet, not fully elucidated interplay of multiple transporters involved in the reabsorption or excretion of urate in the succeeding segments of the nephron. In this context, genome-wide association studies and subsequent functional analyses have identified the ATP-binding cassette (ABC) transporter ABCG2 as an important urate transporter and have highlighted the role of single nucleotide polymorphisms (SNPs) in the pathogenesis of reduced cellular urate efflux, hyperuricemia, and early-onset gout. Recent publications also suggest that ABCG2 is particularly involved in intestinal urate elimination and thus may represent an interesting new target for pharmacotherapeutic intervention in hyperuricemia and gout. In this review, we specifically address the involvement of ABCG2 in renal and extrarenal urate elimination. In addition, we will shed light on newly identified polymorphisms in ABCG2 associated with early-onset gout.

Peripheral artery disease in outpatients with a recent history of acute coronary syndrome or at high atherothrombotic risk

OBJECTIVES

The frequency and implications of peripheral artery disease (PAD) in some risk groups are not entirely characterized in Latin America. We studied PAD prevalence, risk factors, and six-month outcomes in stable outpatients with a history of a recent acute coronary syndrome (ACS), or at high coronary risk.

METHODS

We recruited 830 outpatients in 43 Mexican sites (median age: 64.8 years; 57.8% men). Inclusion criteria were age >18 years, and ACS within 30 days, or age <55 years plus ≥2 major vascular risk factors, or age ≥55 years plus ≥1 vascular risk factors. Patients received standardized assessments at baseline and six-month follow-up for medical history, ankle-brachial index (ABI), and the Edinburgh Claudication Questionnaire (ECQ).

RESULTS

ABI <0.8 was found in 10.5%, <0.9 in 22.5%, >1.3 in 4.8%, and >1.4 in 3.6%, without differences according to sex or selection criteria. Positive ECQ was found in 7.6%. ABI <0.9 was directly associated with age, diabetes, ACS, and chronic kidney disease, but inversely associated with BMI >27. The six-month case-fatality and atherothrombotic events rates were 1.6% and 3.6%, respectively. In patients with ABI <0.9 and ABI <0.8, the six-month case-fatality rates were 2.5% (p = 0.27) and 5.4% (p = 0.03), respectively. In a Cox proportional-hazards model, baseline factors associated with death were age ≥65, ABI <0.8, and ACS.

CONCLUSIONS

Subclinical PAD is more common than symptomatic claudication in high-risk coronary outpatients. Low ABI is associated with reduced short-term survival in patients with recent ACS or at high coronary risk.