Sex-related differences for uric acid in the prediction of cardiovascular events in essential hypertension. A population prospective study

Identifying pathways to cardiovascular mortality by causal graphical models and mediation analysis among hypertensive patients: insights from a prospective study

BACKGROUND

Many biochemical markers are involved in cardiovascular (CV) prognosis in the hypertensive population, but most findings are derived from a single-exposure setting, and their interaction and potential pathways remain scarce. The aim of this study was to determine the direct cause-effect relationship and the mediating effect of CV mortality to suggest potential pathways.

METHODS

This prospective study analysed a data from 3559 hypertensive individuals from the National Health and Nutrition Examination Survey (1999-2018), with their CV mortality ascertained through linkage to the National Death Index on December 31, 2019. Baseline sociodemographic characteristics, habits, medical history data and serum biochemical markers, including cardiometabolic markers, inflammatory markers, liver enzyme markers, blood-cell based inflammatory and immune markers and kidney and renal markers were recorded. The Mixed Graphical Model-Fast-Causal Inference-Maximum algorithm (MGM-FCI-MAX) was applied to build a causal graphical model (CGM) depicting direct and indirect causes of CV mortality, then pathways were further identified from CGM where mediation analyses were performed.

RESULTS

Of the total participants, 562 (15.79%, 302 men and 260 women) CV deaths occurred after a median follow-up of 154 months. Survival analysis revealed significant sex- and ethnicity-specific differences in CV mortality rates (log-rank P < 0.01 and P < 0.01, respectively). Based on the resulting CGM, we identified three direct causes, estimated glomerular filtration rate (eGFR), blood urea nitrogen (BUN) and monocytes, of CV mortality, representing direct pathways underlying kidney and renal function and blood-cell based inflammatory function, respectively. BUN significantly mediated 30.29% of the effect of the eGFR on CV mortality, whereas neither the liver enzyme markers nor insulin pathway with the eGFR as a mediator showed a significant tendency towards a mediated effect after adjusting for covariates. Sex and race were significantly (21.73% and 20.96%, respectively) mediated by monocytes and the eGFR for CV mortality.

CONCLUSION

By using prospective survey data and background clinical knowledge, CGM retrieved direct and indirect causes of CV prognosis and identified pathways and the associated mediated effects. These insights will be useful in designing clinical protocols and targeting improvements in hypertensive patient management.

Trajectory of body shape in early and middle life and hyperuricemia: an observational study integrating mendelian randomization analysis

BACKGROUND AND AIM

Although it is recognized that obesity is linked to hyperuricemia, the research on how obesity at different stages of life affects hyperuricemia is still unclear.

METHODS AND RESULTS

Body shape trajectory of over the first 50 years of life in Henan Rural Cohort Study was accessed by using a group-based trajectory modeling approach. Multivariate logistic regression was utilized to estimate odd ratio (OR) for hyperuricemia. Causation was further assessed using mendelian randomization (MR). Five distinct trajectories were identified and a total of 22,655 participants were enrolled for final analysis. Compared to lean-stable participants, medium-moderate increase, heavy-stable, and lean-marked increase showed significantly higher OR and 95 % confidence interval (CI) for hyperuricemia, with 1.27 (1.07, 1.50), 1.81 (1.48, 2.21) and 1.84 (1.51, 2.25) for women, 1.25 (1.01, 1.54), 1.35 (1.02, 1.77) and 1.91 (1.50, 2.43) for men. This positive association was weakened in women with high healthy lifestyle score, but the weakening effect was not significant in men. Genetically predicted birth weight, childhood body mass index (BMI), and adult BMI were significantly associated with serum uric acid (SUA), with regression coefficient (β) and 95 % CI was -0.09 (-0.14, -0.04), 0.10 (0.04, 0.16), 0.20 (0.16, 0.24), respectively.

CONCLUSION

Body shape trajectory is closely associated with hyperuricemia, with MR analysis suggesting potential causal links. lifelong weight management and maintaining healthy lifestyles can reduce the adverse effects of weight gain on hyperuricemia.

The impact of serum uric acid on biological aging and mortality risk: insights from the NHANES and CHARLS cohorts

Background

Serum uric acid (SUA), a byproduct of purine metabolism, exerts both antioxidant and pro-inflammatory effects, making its role in aging and chronic diseases a subject of ongoing debate. Despite this, the mechanisms by which SUA influences the aging process remain poorly understood.

Methods

We analyzed data from the NHANES (1999-2010) and CHARLS (2011-2015) cohorts to investigate SUA's impact on biological aging. Generalized linear regression models assessed SUA's effect on biological aging markers [ΔKDM-BA, ΔPhenoAge, and allostatic load (AL)], while Cox regression models estimated its association with all-cause and premature mortality. Dose-response relationships between SUA levels and aging markers (ΔKDM-BA, ΔPhenoAge, and AL), as well as all-cause and premature mortality, were evaluated using restricted cubic splines (RCS).

Results

In both cohorts, elevated SUA levels were significantly associated with accelerated aging. In the NHANES cohort, for each 1 mg/dL increase in SUA, ΔKDM-BA increased by 0.52 years (95% CI: 0.43-0.61, p < 0.0001), and AL increased by 0.38 (95% CI: 0.29-0.47, p < 0.0001). In the CHARLS cohort, SUA was similarly linked to an increase in ΔKDM-BA by 0.65 years (95% CI: 0.57-0.74, p < 0.0001) and AL by 0.15 (95% CI: 0.12-0.18, p < 0.0001). RCS analysis revealed a nonlinear association between SUA and ΔKDM-BA in NHANES, with a more pronounced acceleration of aging when SUA levels exceeded 4.16 mg/dL (nonlinear p < 0.0001). In CHARLS, SUA showed a nonlinear relationship with ΔKDM-BA (nonlinear p = 0.01). Additionally, in NHANES, SUA levels were associated with increased all-cause (HR: 1.04, 95% CI: 1.01-1.07, p = 0.01) and premature mortality (HR: 1.06, 95% CI: 1.00-1.13, p = 0.046). RCS analysis further demonstrated a U-shaped nonlinear relationship between SUA levels and both all-cause and premature mortality. In contrast, SUA did not show a significant association with mortality outcomes in the CHARLS cohort.

Conclusion

Elevated SUA is associated with accelerated biological aging in both U.S. and Chinese populations, but its link to mortality was evident only in the NHANES cohort. These findings highlight SUA as a potential aging marker and call for further population-specific investigation.

Two still unanswered questions about uric acid and cardiovascular prevention: Is a specific uric acid cut-off needed? Is hypouricemic treatment able to reduce cardiovascular risk?

AIMS

The most frequent consequence of elevated uric acid (UA) levels is the development of gout and urate kidney disease. Besides these effects, several studies have investigated the association between hyperuricemia and cardiovascular (CV) disease. High serum UA has been identified as an important determinant of all-cause and CV mortality and CV events (acute and chronic coronary syndrome, stroke and peripheral artery disease). Despite the high number of publications on this topic, there are two questions that are still unanswered: do we need a specific CV cut-off of serum UA to better refine the CV risk? Is urate lowering treatment (ULT) able to reduce CV risk in asymptomatic patients? In this review, we will focus on these two points.

DATA SYNTHESIS

Although no doubt exists that the relationship between CV events starts at lower levels than the actually used cut-off, different papers found dissimilar cut-offs. Furthermore, heterogeneity is present depending on the specific CV events evaluated and none of the found cut-off have been tested in external populations (in order to confirm its discriminatory capacity). Furthermore, only few randomized clinical trials on the role of hypouricemic agents in reducing the CV risk have been published giving heterogeneous results. The last published one (ALL-HEART) has strong limitations, that we will deeply discuss.

CONCLUSIONS

A definitive answer to the two questions is impossible with the actually published paper but, over identifying current gaps in knowledge we try to individuate how they can be overruled.

Insights into renal damage in hyperuricemia: Focus on renal protection (Review)

The incidence of hyperuricemia has increased recently, posing a serious threat to public health. Hyperuricemia is associated with an increased risk of gout, chronic kidney disease (CKD), obesity, metabolic syndrome, type 2 diabetes mellitus, hypertension, hypertriglyceridaemia, metabolic dysfunction‑associated steatotic liver disease, acute kidney injury, coronary heart disease and cardiovascular disease (CVD). These diseases are commonly accompanied by varying degrees of kidney damage. A number of randomized controlled clinical trials have investigated the effectiveness of UA‑lowering therapies in preventing kidney disease progression. The present review provided fundamental insights into the pathogenesis, principles and therapeutic approaches for managing hyperuricemia in patients with aforementioned diseases and assesses the effect of uric acid‑lowering therapy on diabetic nephropathy, systemic lupus erythematosus, CKD, CVD and obesity progression.

Gender differences in the prognostic impact of uric acid in patients with heart failure and preserved ejection fraction

BACKGROUND

Uric acid has been identified as an independent predictor of poor outcomes in patients with heart failure with preserved ejection fraction (HFpEF). However, the impact of gender differences on this association is not fully explored.

METHODS

This retrospective cohort study included hospitalized patients with HFpEF from June 2018 to October 2022. The primary outcome was a composite endpoint, defined as the occurrence of all-cause mortality and heart failure readmission. Kaplan-Meier survival analysis and stratified Cox regression examined the combined effect of gender and uric acid on the composite endpoint, and restricted cubic spline curves were applied to visualize the relationship.

RESULTS

The study included 547 patients, with 267 females and 280 males. In the entire cohort, each mg/dL increase in uric acid was associated with a 4% increase in the risk of the composite endpoint (HR: 1.04, 95%CI:1.01-1.09). This association was more pronounced in females, with a 9% increase in the risk of the composite endpoint per mg/dL increase in uric acid (95%CI: 1.02-1.17). Restrict cubic spline curves analysis demonstrated a significant linear correlation between increasing uric acid levels and higher risk of the composite endpoint in female patients (P = 0.028). Kaplan-Meier analysis revealed higher survival probabilities for females compared to males (P = 0.002). However, survival rates for females with high uric acid levels were similar to those for males with high uric acid levels.

CONCLUSIONS

Baseline serum uric acid levels are significantly associated with the composite endpoint in patients with HFpEF, particularly among females.

Asymptomatic Hyperuricemia and the Kidney: Lessons from the URRAH Study

Chronic kidney disease (CKD) is a prevalent global health concern affecting approximately 850 million people worldwide, with a significant and rising mortality rate. CKD often coexists with hyperuricemia (HSUA), which is also increasingly common due to its association with hypertension, obesity, and diabetes. The interplay between hyperuricemia and CKD is complex; while in vitro studies and animal models support a role for uric acid mediating glomerular and tubule-interstitial damage, and HSUA has been shown to predict the onset and progression of CKD, the expectations of renal protection by the use of urate lowering treatment (ULT) are inconsistent. A significant challenge in managing asymptomatic HSUA in CKD patients lies in determining the appropriate SUA threshold values. Recent research, including the URRAH project, has sought to identify SUA cut-offs predictive of cardiovascular mortality, but these thresholds may vary depending on the severity of CKD. This variability complicates the establishment of universal guidelines for treating asymptomatic HSUA, leading to a lack of specific recommendations in clinical practice. In conclusion, while hyperuricemia is recognized as a prognostic factor for CKD and cardiovascular risk, more research is needed to refine the threshold values for SUA and to identify which patients may benefit from ULT. Stratification based on glomerular filtration rate may be necessary to tailor the treatments and improve outcomes in this population.

Natural polysaccharides in the prevention of hyperuricemia: Source, classification, mechanism, application in food industry

Hyperuricemia (HUA) is one of the major threats to human health. In recent years, with the gradual increase in the incidence rate of Hua, the prevention and treatment of HUA has attracted more and more attention. Clinical pharmaceutical interventions, such as Allopurinol, Febuxostat, and so on, though effective, are usually accompanied by notable adverse effects. Therefore, alternative therapy with high-safety natural components has received more and more attention from scholars. The natural polysaccharides showed a significant potential in HUA therapy and more and more natural polysaccharides for treating HUA were being obtained. Therefore, in this review, the recent progress on natural polysaccharides in preventing HUA was presented focusing on the sources, classification, and biological activities (oxidative stress, anti-inflammatory, and UA-lowering) of natural polysaccharides. Furthermore, this review explores the mechanisms of action and application. It is beneficial to the development of polysaccharides for natural HUA therapy and the results of this review could offer guidance on preventing the occurrence of HUA in daily life.

Uric acid and metabolic syndrome: Importance of hyperuricemia cut-off

BACKGROUND

The relationship between HyperUricemia (HU) and Metabolic Sindrome (MS) and if Uric Acid (UA) should be inserted into MS definitions is a matter of debate. Aim of our study was to evaluate the correlation between UA and HU with Insulin Resistance (IR) and MS in a population of hypertensive patients. HU was defined with two cut-offs (the classic one of ≥6 mg/dL for women and ≥ 7 for men; the newly proposed URRAH one with ≥5.6 mg/dL for both sexes).

METHODS

We enrolled 473 Hypertensive patients followed by the Hypertension Unit of San Gerardo Hospital (Monza, Italy). IR was defined through TG/HDL ratio and NCEP-ATP-III criteria were used for MS diagnosis.

RESULTS

MS was found in 33.6 % while HU affected 14.8 % of subjects according to the traditional cut-off and 35.9 % with the URRAH cut-off. 9.7 % (traditional cut-off) and 17.3 % (URRAH's threshold) of the subjects had both HU and MS. UA level was significantly higher in MS group (5.7 vs 4.9 mg/dL, p < 0.0001) as well as for HU (29.0 vs 7.6 % and 51.6 vs 28.0 %, for classic and URRAH cut-off respectively, p < 0.0001 for both comparison). Logistic multivariable regression models showed that UA is related to MS diagnosis (OR = 1.608 for each 1 mg/dL), as well as HU with both cut-off (OR = 5.532 and OR = 3.379, p < 0.0001 for all comparison, for the classic cut-off and the URRAH one respectively).

CONCLUSIONS

The main finding of our study is that UA and HU significantly relate to IR and MS. The higher the values of UA and the higher the cut-off used, the higher the strength of the relationship.

Linear associations of Chinese visceral adiposity index and its change with hyperuricemia: A prospective cohort study

BACKGROUND AND AIMS

This study aims to investigate the association of Chinese visceral adiposity index (CVAI) with incident hyperuricemia (HUA).

METHODS AND RESULTS

We included 5186 adults aged ≥45 years from China Health and Retirement Longitudinal Study. Modified Poisson regression model was used to estimate the relative risks (RRs) of incident HUA associated with baseline CVAI, and logistic model was used to estimate the odds ratios (ORs) of HUA for CVAI change. Restricted cubic splines analysis was adopted to model the dose-response associations. The area under the receiver operating characteristic curve (AUC) analysis was used to evaluate the predictive value of CVAI. During 4-year follow-up, a total of 510 (9.8%) HUA cases were identified. The RRs (95%CIs) of incident HUA were 3.75 (2.85-4.93) for quartile 4 versus quartile 1 and 1.56 (1.45-1.69) for per-standard deviation increase in baseline CVAI. For the analyses of CVAI change, compared with stable group, participants in decreased group had 34% lower risk (OR 0.66, 95%CI 0.49-0.87) and those in increased group had 35% (1.35, 1.03-1.78) higher risk of HUA. Linear associations of baseline CVAI and its change with HUA were observed (Pnonlinear >0.05). Besides, the AUC value for HUA was 0.654 (0.629-0.679), which was higher than other five obesity indices.

CONCLUSIONS

Our study found linear associations between baseline CVAI and its change and risk of HUA. CVAI had the best predictive performance in predicting incident HUA. These findings suggest CVAI as a reliable obesity index to identify individuals with higher HUA risk.

Caution for Multidrug Therapy: Significant Baroreflex Afferent Neuroexcitation Coordinated by Multi-Channels/Pumps Under the Threshold Concentration of Yoda1 and Dobutamine Combination

Multi-drug therapies are common in cardiovascular disease intervention; however, io channel/pump coordination has not been tested electrophysiologically. Apparently, inward currents were not elicited by Yoda1/10 nM or Dobutamine/100 nM alone in Ah-type baroreceptor neurons, but were by their combination. To verify this, electroneurography and the whole-cell patch-clamp technique were performed. The results showed that Ah- and C-volley were dramatically increased by the combination at 0.5 V and 5 V, in contrast to A-volley, as consistent with repetitive discharge elicited by step and ramp with markedly reduced current injection/stimulus intensity. Notably, a frequency-dependent action potential (AP) duration was increased with Iberiotoxin-sensitive K+ component. Furthermore, an increased peak in AP measured in phase plots suggested enhanced Na+ influx, cytoplasmic Ca2+ accumulation through reverse mode of Na+/Ca2+ exchanger, and, consequently, functional KCa1.1 up-regulation. Strikingly, the Yoda1- or Dbtm-mediated small/transient Na+/K+-pump currents were robustly increased by their combination, implying a quick ion equilibration that may also be synchronized by hyperpolarization-induced voltage-sag, enabling faster repetitive firing. These novel findings demonstrate multi-channel/pump collaboration together to integrate neurotransmission at the cellular level for baroreflex, providing an afferent explanation in sexual dimorphic blood pressure regulation, and raising the caution regarding the individual drug concentration in multi-drug therapies to optimize efficacy and minimize toxicity.

Impact of Chronic Kidney Disease and Gout on End-Stage Renal Disease in Type 2 Diabetes: Population-Based Cohort Study

BACKGRUOUND

We examined the impact of gout on the end-stage renal disease (ESRD) risk in patients with type 2 diabetes mellitus (T2DM) and determined whether this association differs according to chronic kidney disease (CKD) status.

METHODS

Using the Korean National Health Insurance Service, this nationwide cohort study enrolled 847,884 patients with T2DM who underwent health checkups in 2009. Based on the presence of CKD (estimated glomerular filtration rate <60 mL/min/1.73 m2) and gout (two outpatient visits or one hospitalization within 5 years), patients were classified into four groups: CKD-Gout-, CKD- Gout+, CKD+Gout-, and CKD+Gout+. Patients with incident ESRD were followed up until December 2018.

RESULTS

Among 847,884 patients, 11,825 (1.4%) experienced progression to ESRD. ESRD incidence increased in the following order: 0.77 per 1,000 person-years (PY) in the CKD-Gout- group, 1.34/1,000 PY in the CKD-Gout+ group, 8.20/1,000 PY in the CKD+Gout- group, and 23.06/1,000 PY in the CKD+Gout+ group. The presence of gout modified the ESRD risk in a status-dependent manner. Hazard ratios (HR) were 1.49 (95% confidence interval [CI], 1.32 to 1.69) and 2.24 (95% CI, 2.09 to 2.40) in patients without and with CKD, respectively, indicating a significant interaction (P<0.0001). The CKD+Gout+ group had a markedly higher risk of developing ESRD (HR, 18.9; 95% CI, 17.58 to 20.32) than the reference group (CKD-Gout-).

CONCLUSION

Gout substantially enhances the risk of ESRD, even in the absence of CKD. Concurrent CKD and gout synergistically increase the risk of ESRD. Therefore, physicians should carefully screen for hyperuricemia to prevent progression to ESRD.

Prognostic Significance of Serum Uric Acid and Exercise Capacity in Older Adults Hospitalized for Worsening Cardiovascular Disease

Elevated serum uric acid (sUA) is associated with the risk of developing cardiovascular disease (CVD). Here, we examined the prognostic significance of sUA and exercise capacity in 411 Japanese adults (age, ≥65; mean, 81 years) hospitalized for worsening CVD. When the patients were stratified by sUA into three groups (<5.3, 5.4-6.9, >7.0 mg/dL), the high-sUA group had a significantly worse peak VO2 and composite endpoint (rehospitalization due to worsening CVD and all-cause mortality) compared with low- and moderate-sUA groups (p < 0.001). When the patients were stratified by sUA into five groups (sUA < 3.9, 4.0-5.9, 6.0-7.9, 8.0-8.9, and >10.0 mg/dL), the incidence of the composite endpoint was significantly higher in the highest sUA group compared with that in the reference group, but only in women. Univariate Cox regression analysis, but not a multivariate analysis, indicated that sUA was significantly associated with the composite endpoint. Although sUA and exercise capacity may have some degree of prognostic significance in older patients with CVD, this significance may differ between men and women.

L-shaped association between lean body mass to visceral fat mass ratio with hyperuricemia: a cross-sectional study

BACKGROUND

Insufficient attention has been given to examining the correlation between body composition and hyperuricemia, leading to inconsistent findings. The primary objective of this research is to explore the association between lean body mass index (LMI), visceral fat mass index (VFMI), and hyperuricemia. A specific emphasis will be placed on assessing the link between the ratio of lean body mass to visceral fat mass (LMI/VFMI) and hyperuricemia.

METHODS

The present study employed a cross-sectional design and involved a total of 9,646 individuals who participated in the National Health and Nutrition Examination Survey (NHANES). To explore the associations among the variables, logistic and linear regressions were employed. Additionally, subgroup analyses and sensitivity analyses were conducted based on various characteristics.

RESULTS

The results showed that LMI was positively associated with hyperuricemia (for Per-SD: OR = 1.88, 95%CI: 1.75, 2.01; for quartiles [Q4:Q1]: OR = 5.37, 95%CI: 4.31, 6.69). Meanwhile, VFMI showed a positive association with hyperuricemia (for Per-SD: OR = 2.02, 95%CI: 1.88, 2.16; for quartiles [Q4:Q1]: OR =8.37, 95%CI: 6.70, 10.47). When considering the effects of In LMI/VFMI, an L-shaped negative association with hyperuricemia was observed (for Per-SD: OR = 0.45, 95%CI: 0.42, 0.49; for quartiles [Q4:Q1]: OR = 0.16, 95%CI: 0.13, 0.20). Subgroup and sensitivity analyses demonstrated the robustness of this association across different subgroups. Additionally, the segmented regression analysis indicated a saturation effect of 5.64 for the In LMI/VFMI with hyperuricemia (OR = 0.20, 95%CI: 0.17, 0.24). For every 2.72-fold increase of In LMI/VFMI, the risk of hyperuricemia was reduced by 80%.

CONCLUSION

The LMI/VFMI ratio is non-linearly associated with serum uric acid. Whether this association is causal needs to be confirmed in further longitudinal studies or Mendelian randomization.

Gender differences in the relationship between serum uric acid and the long-term prognosis in heart failure: a nationwide study

BACKGROUND

Serum uric acid (SUA) is an important pathogenetic and prognostic factor for heart failure (HF). Gender differences are apparent in HF. Furthermore, gender differences also exist in the association between SUA and prognosis in various cardiovascular diseases. However, the gender difference for SUA in the prediction of long-term prognosis in HF is still ambiguous.

METHODS

A total of 1593 HF patients (897 men, 696 women) from the National Health and Nutrition Examination Survey (NHANES) 1999-2018 cycle were enrolled in our final analysis. Participants were categorized according to gender-specific SUA tertile. We assessed the association between SUA and long-term prognosis of HF patients, defined as all-cause mortality and cardiovascular mortality, in different genders via Kaplan-Meier curve analysis, Cox proportional hazard model, and Fine-Gray competing risk model. The restricted cubic spline (RCS) was performed to investigate the dose-response relationship between SUA and outcomes.

RESULTS

Gender differences exist in demographic characteristics, clinical parameters, laboratory tests, and medication of HF patients. After a median follow-up of 127 months (95% CI 120-134 months), there were 853 all-cause deaths (493 events in men, 360 events in women) and 361 cardiovascular deaths (206 events in men, 155 events in women). Kaplan-Meier analysis showed that SUA had gender difference in the prediction of cardiovascular mortality (Log-rank p < 0.001, for male, Log-rank p = 0.150, for female), but not in all-cause mortality. Multivariate Cox regression analysis revealed that elevated SUA levels were associated with higher all-cause mortality and cardiovascular mortality in men (HR 1.11, 95% CI 1.05-1.18, p < 0.001, for all-cause death; HR 1.18, 95% CI 1.09-1.28, p < 0.001, for cardiovascular death), but not in women (HR 1.05, 95% CI 0.98-1.12, p = 0.186, for all-cause death; HR 1.01, 95% CI 0.91-1.12, p = 0.902, for cardiovascular death). Even using non-cardiovascular death as a competitive risk, adjusted Fine-Gray model also illustrated that SUA was an independent predictor of cardiovascular death in men (SHR 1.17, 95% CI 1.08-1.27, p < 0.001), but not in women (SHR 0.98, 95% CI 0.87 - 1.10, p = 0.690).

CONCLUSIONS

Gender differences in the association between SUA and long-term prognosis of HF existed. SUA was an independent prognostic predictor for long-term outcomes of HF in men, but not in women.