Uric acid levels predict future blood pressure and new onset hypertension in the general Japanese population

Association between hyperuricemia and hypertension and the mediatory role of obesity: a large cohort study in China

OBJECTIVE

This study aimed to investigate the sex-specific association between hyperuricemia and the risk of hypertension and whether obesity mediates this association.

METHODS

This study included 31,395 (47.0% women) adults without hypertension, cardiovascular disease, or cancer at baseline who completed at least one follow-up annual examination between 2009 and 2016. Cox regression models were performed to calculate hazard ratios and 95% confidence intervals. Mediation analysis was conducted to estimate the effect of body mass index on the association between hyperuricemia and hypertension.

RESULTS

During a median 2.9-year follow-up, hyperuricemia was significantly associated with a higher risk of hypertension (HR 1.15, 95%CI 1.07-1.24 for all participants; HR 1.12, 95%CI 1.03-1.22 for men; and HR 1.23, 95%CI 1.02-1.48 for women) after adjustment for potential confounders. Additional adjustment for body mass index attenuated this association (HR 1.09, 95%CI 1.08-1.10 for all participants; HR 1.07; 95%CI 0.98-1.16 for men; HR 1.18; 95%CI 0.96-1.44 for women). Mediation analysis showed that BMI partially mediated the relationship between hyperuricemia and incident hypertension (indirect effect HR 1.09, 95%CI 1.08-1.10; direct effect: HR 1.08, 95%CI 1.02-1.15). The percentage of the mediation effect was 53.2% (95%CI 37.9-84.5).

CONCLUSION

Hyperuricemia is associated with a risk of hypertension in both sexes, and BMI partially mediates hyperuricemia-related incident hypertension.

Effect of chronic kidney disease on the association between hyperuricemia and new-onset hypertension in the general Japanese population: ISSA-CKD study

We aimed to investigate the association between serum uric acid (SUA) level and development of hypertension as well as the interaction effect of chronic kidney disease (CKD) on this relationship in the general Japanese population. We included 7895 participants aged ≥30 years from the ISSA‐CKD study, a population‐based retrospective cohort study that used annual health check‐up data of residents from Iki Island, Japan. After the exclusion of 1881 with l < 1‐year follow‐up, 2812 with hypertension at baseline, and 165 with missing information on SUA, a total of 3037 participants were enrolled in this analysis. Participants were divided into four groups according to the quartiles of SUA level at baseline, and multivariable‐adjusted hazard ratios for new‐onset hypertension were calculated. Stratified analyses were performed for each subgroup (defined by sex, age, alcohol intake, and CKD) to assess the interaction effects. During a mean follow‐up period of 4.4 years, 943 participants developed hypertension. The first quartile group was set as the reference group, and the multivariable‐adjusted hazard ratios (95% confidence interval) for new‐onset hypertension were 1.11 (0.90–1.36) in the second quartile, 1.25 (1.02–1.54) in the third quartile, and 1.35 (1.07–1.70) in the fourth quartile compared with those in the reference group (p = .007 for trend). The stratified analyses showed that the association between SUA and hypertension was significantly stronger in participants with CKD than in those without CKD (p = .035 for interaction). SUA level is an independent risk factor for new‐onset hypertension. This tendency was significantly stronger in participants with CKD.

Dose-response association between serum uric acid levels and incident hypertension: a systematic review and meta-analysis of 17 prospective cohort studies of 32 thousand participants

BACKGROUND

Various magnitudes of the risk of incident hypertension (IHTN) have been reported to be associated with increased serum uric acid (SUA) levels in observational studies, however, whether a dose-response relation exists is unclear. We aimed to quantitatively evaluate the SUA-IHTN association.

METHODS

We searched the PubMed and Embase databases for relevant articles published prior to 21 October 2019. Random-effects models were used to estimate the summary relative risks (RRs) and 95% confidence intervals (CIs) of the IHTN risk in relation to SUA levels. We used restricted cubic splines to model the dose-response association between SUA levels and IHTN.

RESULTS

A total of 17 articles (17 prospective cohort studies) including 321,716 adults and 65,890 IHTN cases were identified. The pooled RR was 1.10 (95% CI 1.07-1.13; I²=90.7%; n = 17) per 1 mg/dL change in the SUA level. In addition, we found evidence of a linear and positive dose-response association between SUA levels and IHTN (P_{non-linearity} = 0.069). The results of the subgroup and sensitivity analyses were consistent with those of the primary analysis.

CONCLUSION

These data suggested that people with higher SUA levels had a higher IHTN risk. SUA levels need to be controlled to reduce or eliminate the risk of IHTN associated with SUA levels. Clinical trial studies or diagnostic studies are needed to determine the optimal cut-off point for SUA.

Uric acid can enhance MAPK pathway-mediated proliferation in rat primary vascular smooth muscle cells via controlling of mitochondria and caspase-dependent cell death

Hyperuricemia may be a risk factor for cardiovascular diseases such as hypertension and atherosclerosis, but the mechanisms underlying uric acid-induced pathological conditions remain unknown. In this study, we investigated the effect of short time and long-term administration of increasing uric acid concentrations on cell viability, proliferative and apoptotic pathways in vascular smooth muscle cells (VSMCs). Cell viability/proliferation was determined with WST-1 assay. Expression levels of mitogen-activated protein kinases (MAPKs) (phosphorylated (p)-p38 and p-p44/42 MAPK), extrinsic (caspase 3, caspase 8), and intrinsic (B-cell lymphoma-extra-large (Bcl-xL)) apoptotic pathway proteins were measured by Western blotting. In order to assess the proliferative effects of uric acid incubations on VSMCs, we monitored the proliferative/apoptosis signaling pathways for up to 24 h. Our results indicated that uric acid increases cell viability at time and dose-dependently in VSMCs. Immunoblotting results showed that uric acid treatment elevated the expression level of p-p38 MAPK but did markedly reduce the protein levels of p-p44/42, compared with all the uric acid doses-treated VSMCs, especially at 1 h. Uric acid stimulation increased caspase-3 protein levels and decreased Bcl-xL, but did not alter caspase-8 protein expression at the same dose and time. Furthermore, low uric acid incubations (0-7.5 mg/dL) did not affect any signaling pathways for long time points (6-24 h). In conclusion, our study demonstrates for the first time that VSMCs induced with uric acid can affect cell viability, proliferative, and apoptosis pathways at the widest time and dose range. These findings provide a better understanding of the uric acid effects related to vascular impairments.

Age and sex dependent association of uric acid and incident hypertension

BACKGROUND AND AIMS

A previous meta-analysis suggested that the relationship between hyperuricemia and hypertension may be stronger in younger individuals and women. We aimed to investigate the age and sex dependent association of uric acid (UA) and incident hypertension.

METHODS AND RESULTS

We analyzed data from the Health Examinees Study, a community-based prospective cohort study conducted in Korea from 2004 to 2013. It included 29,088 non-hypertensive subjects aged 40-79 (age, 52.5 ± 7.8 years; men, 31.4%) who had serum UA measurement and participated in the follow-up survey. The risk factors of hypertension were assessed using Cox regression. Over a mean 3.8 years of follow-up, 1388 men (15.2%) and 1942 women (9.7%) were newly diagnosed with hypertension. Upon age- and sex-based stratification, the risk of hypertension was highest in hyperuricemic subjects aged 40-49 years (HR: women, 2.16; men, 1.30). Across the entire cohort, the risk of incident hypertension was higher in groups with higher serum UA levels, and highest in women aged 40-49 years (HR, 1.44; P < 0.001). On multivariable linear regression analysis, the higher the baseline serum UA level, the greater the increase in blood pressure during follow-up, and this effect was strongest in women aged 40-49 years (β = 0.87 and P < 0.01 for systolic blood pressure).

CONCLUSIONS

The relationship between uric acid and incident hypertension tended to be dependent on age and sex. Younger women are at highest risk of UA-related incident hypertension.

Predictive Value of Uric Acid Regarding Cardiometabolic Disease in a Community-Dwelling Older Population in Shanghai: A Cohort Study

Aim: This study aimed to test the predictive power of serum uric acid (UA) levels on new-onset cardiometabolic risk in the Chinese population.

Methods: Older people who visited a community health center for a yearly health check (N = 5,000; men: 47%, women: 53%) were enrolled. Participants were followed for 4 years from baseline (median: 48 months), with the endpoints being development of heart failure, atrial fibrillation, diabetes, hypertension, metabolic syndrome, or kidney disease.

Results: During follow-up, 342 men (7.4%) and 360 women (8.6%) developed hypertension; 98 men (2.48%) and 135 women (3.06%) developed diabetes; and 175 men (5.04%) and 214 women (4.51%) developed metabolic syndrome. Incident diabetes, hypertension, and metabolic syndrome increased with increased UA levels at baseline (P < 0.001). A multivariate Cox proportional hazards analysis revealed a significant, independent association between the baseline UA level and the onset and future hypertension and/or diabetes in both men and women. However, UA is associated with the development of metabolic syndrome in men, but not in women.

Conclusion: UA is an independent predictor of new-onset diabetes and hypertension in both women and men and a predictor of new-onset metabolic syndrome only in men.

Impact of uric acid on incident hypertension: Sex-specific analysis in different age groups

The aim of the present study is to evaluate the association of serum uric acid (UA) levels with the risk of incident hypertension among different age groups in men and women using a single large Japanese general cohort. The present study is based on annual health check-up program in Gunma, Japan. We studied 12,029 participants (mean age, 48 ​± ​9 years old; 31% women) free of prevalent cardiovascular disease and hypertension at baseline (2009). Hypertension was defined by self-report, hypertensive medication use, or measured BP ​> ​140/90 ​mmHg ​at each visit. Discrete proportional hazards regression model was used to evaluate the association of UA level at baseline with incident hypertension through 2012 adjusted for age, gender, baseline blood pressure, and other CVD risk factors among different age decade groups in men and women. During follow-up of 3 years, 12% of the cohort (n ​= ​1457) developed hypertension. UA was strongly associated with incident hypertension in the multivariable model in all participants. In age-stratified analysis, participants below 50 years of age in men had the significant association of UA with incident hypertension, whereas participants above 50 years did not. In women, participants above 40 years had the significant association, whereas participants below 40 years did not. The present data suggest that UA level is an independent predictor for incident hypertension among middle aged men below 50 years old and middle aged and the elderly women above 40 years.

Effects of serum uric acid on blood-pressure lowering treatment

If hyperuricemia is an independent risk factor in blood-pressure control, urate-lowering therapy should be used to reduce cardiovascular risk. It may also act as a prognostic marker of other abnormalities. This review presents current evidence on the relationship between hyperuricemia and hypertension.

Uric Acid Levels Can Predict Metabolic Syndrome and Hypertension in Adolescents: A 10-Year Longitudinal Study

The relationships between uric acid and chronic disease risk factors such as metabolic syndrome, type 2 diabetes mellitus, and hypertension have been studied in adults. However, whether these relationships exist in adolescents is unknown. We randomly selected 8,005 subjects who were between 10 to 15 years old at baseline. Measurements of uric acid were used to predict the future occurrence of metabolic syndrome, hypertension, and type 2 diabetes. In total, 5,748 adolescents were enrolled and followed for a median of 7.2 years. Using cutoff points of uric acid for males and females (7.3 and 6.2 mg/dl, respectively), a high level of uric acid was either the second or third best predictor for hypertension in both genders (hazard ratio: 2.920 for males, 5.222 for females; p<0.05). However, uric acid levels failed to predict type 2 diabetes mellitus, and only predicted metabolic syndrome in males (hazard ratio: 1.658; p<0.05). The same results were found in multivariate adjusted analysis. In conclusion, a high level of uric acid indicated a higher likelihood of developing hypertension in both genders and metabolic syndrome in males after 10 years of follow-up. However, uric acid levels did not affect the occurrence of type 2 diabetes in both genders.

Allopurinol treatment improves renal function in patients with type 2 diabetes and asymptomatic hyperuricemia: 3-year randomized parallel-controlled study

OBJECTIVE

To investigate the effects of long-term effective control of serum uric acid on renal function in patients with type 2 diabetes and asymptomatic hyperuricemia.

METHODS

Application of randomized open parallel-controlled methods, a total of 176 patients with type 2 diabetes and asymptomatic hyperuricemia were selected, and was randomly divided into two groups for allopurinol or conventional treatments, respectively. Changes in urinary albumin excretion rate (UAER), the levels of serum creatinine and glomerular filtration rate (GFR) and the incidence of new-onset diabetic nephropathy (DN) and hypertension in patients before and after 3 years of treatment were measured and compared between groups.

RESULTS

There were no statistically significant difference in the baseline clinical characteristics of study participants between two treatment groups (P > 0·05 for all). After 3 years of treatment, compared to the conventional treatment, the allopurinol treatment was more effective in reducing serum uric acid, UAER, serum creatinine (P < 0·01 for all) and increasing GFR (P < 0·01). The intention-to-treat (ITT) analysis indicated that the incidence of new-onset DN and hypertension in the allopurinol group showed a declining trend compared to that in the conventional treatment group, despite a lack of significant difference (P > 0·05).

CONCLUSION

Long-term effective control of serum uric acid can decrease UAER and serum creatinine, increase GFR and may exert kidney protection effects in patients with type 2 diabetes and asymptomatic hyperuricemia.

The Effects of Allopurinol on the Carotid Intima-media Thickness in Patients with Type 2 Diabetes and Asymptomatic Hyperuricemia: A Three-year Randomized Parallel-controlled Study

OBJECTIVE

The aim of this study was to investigate the long-term effective control of serum uric acid by allopurinol on the carotid intima-media thickness (IMT) in patients with type 2 diabetes (T2DM) and asymptomatic hyperuricemia (HUA).

METHODS

This was a randomized open parallel-controlled study. In this study, 176 patients with T2DM and asymptomatic HUA were randomly allocated to the conventional or allopurinol treatment groups on the basis of a computer-generated random number table. Changes in the carotid IMT, biochemical indexes, high sensitive C-reactive protein (hs-CRP) and the incidence of hypertension in patients before and after three years of treatment were examined and compared between the groups.

RESULTS

There were no statistically significant differences in the baseline characteristics of the study participants between the two treatment groups (p>0.05 for all). Nevertheless, the serum uric acid, triglyceride, and hs-CRP levels and the homeostasis assessment for insulin resistance (HOMA-IR), systolic blood pressure, diastolic blood pressure and the carotid IMT in the allopurinol group were significantly lower than those in the conventional group after three years of treatment (p<0.01 for all). The intention-to-treat analysis indicated that the incidence of new-onset hypertension in the allopurinol group showed a declining trend compared to that in the conventional treatment group (6.8% vs. 13.6%, p>0.05).

CONCLUSION

The long-term effective control of serum uric acid by allopurinol may improve insulin resistance, decrease the serum levels of hs-CRP, reduce the carotid IMT, and may delay the development of atherosclerosis in patients with T2DM and asymptomatic HUA.