Association of Blood Pressure Trajectories in Early Life with Subclinical Renal Damage in Middle Age

Association of Longitudinal Trajectories of Systolic BP with Risk of Incident CKD: Results from the Korean Genome and Epidemiology Study

BACKGROUND

Although hypertension is a well known risk factor for CKD, few studies have evaluated the association between temporal trends of systolic BP and kidney function decline in persons without hypertension.

METHODS

We studied whether changes in systolic BP over time could influence incident CKD development in 4643 individuals without CKD and hypertension participating in the Korean Genome and Epidemiology Study, a prospective community-based cohort study. Using group-based trajectory modeling, we categorized three distinct systolic BP trajectories: decreasing, stable, and increasing. The primary outcome was incident CKD development, defined as two consecutive eGFR measurements <60 ml/min per 1.73 m².

RESULTS

Among participants with an increasing systolic BP trajectory, systolic BP increased from 105 to 124 mm Hg. During 31,936 person-years of follow-up (median 7.7 years), 339 participants developed incident CKD. CKD incidence rates were 8.9, 9.6, and 17.8 cases per 1000 person-years in participants with decreasing, stable, and increasing systolic BP trajectories, respectively. In multivariable cause-specific Cox analysis, after adjustment of baseline eGFR, systolic BP, and other confounders, increasing systolic BP trajectory associated with a 1.57-fold higher risk of incident CKD (95% confidence interval, 1.20 to 2.06) compared with a stable trajectory. There was a significant effect modification of baseline systolic BP on the association between systolic BP trajectories and CKD risk (P value for interaction =0.02), and this association was particularly evident in participants with baseline systolic BP <120 mm Hg. In addition, increasing systolic BP trajectory versus a stable trajectory was associated with higher risk of new development of albuminuria.

CONCLUSIONS

Increasing systolic BP over time without reaching the hypertension threshold is associated with a significantly increased risk of incident CKD in healthy adults.

Association of Uric Acid in Serum and Urine with Arterial Stiffness: Hanzhong Adolescent Hypertension Study

Background

Hyperuricemia has long been associated with increased cardiovascular risk, and arterial stiffness is proposed as a mediator. The present study is aimed at examining the associations of uric acid (UA) in blood and urine with arterial stiffness in a Chinese cohort.

Methods

A total of 2296 participants (mean age: 43.0 years) from our previously established cohort of Hanzhong Adolescent Hypertension Study were included. The participants were classified as subjects with or without arterial stiffness, which was defined as brachial-ankle pulse wave velocity (baPWV) ≥ 1400 cm/s and/or carotid intima-media thickness (CIMT) ≥ 0.9 mm. Multivariate regression analyses were used to examine the relationship between serum and urinary UA and the risk of arterial stiffness after adjusting for age, gender, systolic blood pressure, fasting glucose, BMI, heart rate, total cholesterol, and triglycerides.

Results

baPWV was positively correlated with urinary uric acid/creatinine ratio (uUA/Cre) (β = 0.061, P < 0.001), while CIMT was correlated with uUA/Cre (β = 0.085, P < 0.001) and fractional excretion of uric acid (FEUA) (β = 0.044, P = 0.033) in all subjects. In addition, uUA/Cre was significantly associated with the risk of high baPWV [1.032 (1.019-1.045)] and arterial stiffness [1.028 (1.016-1.040)].

Conclusion

Our study showed that urinary UA excretion was significantly associated with the risk of arterial stiffness in Chinese adults. These findings suggest that UA, especially urinary UA, may be used as a simple, noninvasive marker for early detection of arterial stiffness in otherwise healthy subjects.

Effect of metabolically healthy obesity on the development of arterial stiffness: a prospective cohort study

Background

Metabolically healthy obesity (MHO) has been reported to be associated with the development of vascular damage by the carotid intima-media thickness, but the relationship between metabolic health and obesity phenotypes and arterial stiffness is still unknown. Our hypothesized that different metabolic health and obesity phenotypes might be associated with the development of arterial stiffness, and that subjects in MHO phenotype might not have increased risks of arterial stiffness compared with those in metabolically healthy nonobesity phenotype (MHNO), while metabolic unhealthy individuals might have increased risks of arterial stiffness.

Methods

A prospective cohort of 2076 participants (aged 36-48 years) who were enrolled in the Hanzhong Adolescent Hypertension Cohort Study in 2017 was analyzed in a cross-sectional analysis. A subgroup of 202 participants from 2005 to 2017 was selected by an isometric sampling method and was included in the final longitudinal analysis.

Results

We identified four metabolic health and obesity phenotypes for both the cross-sectional and longitudinal analyses as follows: MHNO, metabolically unhealthy nonobesity (MUNO), MHO, and metabolically unhealthy obesity (MUO). In the cross-sectional analysis, individuals with the MHO phenotype had the lowest brachial-ankle pulse wave velocity (baPWV) levels of the four phenotypes (P < 0.001), and participants with the MHO phenotype had a similar risk of arterial stiffness after fully adjustment [odds ratio (OR) = 0.99 (0.61-1.60)] as the MUNO subjects. Subjects with metabolically unhealthy status had a significantly higher risk of arterial stiffness than the MHNO individuals, particularly females (P < 0.005). In the longitudinal analysis, subjects with the MUNO and MUO phenotypes had a significantly higher risk of arterial stiffness than the MHNO individuals after adjustment for age and sex [OR = 5.21 (2.26-12.02), OR = 3.32 (1.18-9.32), respectively].

Conclusions

The MHO phenotype did not significantly increase the progression of arterial stiffness. Metabolically unhealthy individuals (MUNO, MUO), regardless of obesity status, showed a worse effect for the development of arterial stiffness, particularly females.

Trial registration

NCT02734472. Registered 12 April 2016 - Retrospectively registered, http:www.clinicaltrials.gov.

Evidence Gaps in the Identification and Treatment of Hypertension in Children

The ultimate goal of recognizing and treating hypertension in childhood is to prevent target-organ damage during childhood and to reduce the risk of adulthood cardiovascular disease. The quality of evidence to guide blood pressure management in children is lower than in adult medicine, yet some common findings support clinical practice recommendations. Oscillometric devices are increasingly replacing manual blood pressure measurements, but evidence shows that readings are not equivalent between the 2 methods. In addition, multiple blood pressure readings are needed before diagnosing a child with hypertension, but the optimal number and timing are still being determined. The recent American Academy of Pediatrics blood pressure guideline has revised the normative data tables and included threshold blood pressure limits which seem to identify children with higher cardiovascular risks. Threshold limits vary between guidelines, and the most accurate threshold has yet to be determined. Lifestyle modifications are a cornerstone of hypertension management, but the optimal diet and physical activity changes for beneficial effect are not known. When pharmacotherapy is needed, physicians have used drugs from all antihypertensive classes in children, yet only a few classes have been systematically studied. The long-term cardiovascular consequences of elevated blood pressure during childhood are under investigation and it seems that the lower the childhood blood pressure the better and that the rate of change during childhood is predictive of adulthood disease. With much still to learn, this article summarizes the evidence and the evidence gaps for the diagnosis, investigation, management, and outcomes of pediatric hypertension.

The predictive value of repeated blood pressure measurements in childhood for cardiovascular risk in adults: the Hanzhong Adolescent Hypertension Study

There is currently a lack of strong evidence linking childhood elevated blood pressure to long-term cardiovascular risk in adulthood. Repeated observations of abnormal blood pressure in childhood may enhance the prediction of cardiovascular risk in adulthood compared with a single observation. The study included 1738 individuals in rural areas of Hanzhong City, Shaanxi, who had been followed for 30 years since baseline (1987, at which time participants were aged 6-15 years). According to four independent measurements of blood pressure in 1987, 1989, 1992, and 1995, childhood elevated blood pressure was defined as 2 in-person examinations with blood pressure values above the 90th percentile. Arterial stiffness and left ventricular hypertrophy in adulthood were assessed by brachial-ankle pulse wave velocity and the Cornell product index, respectively. Childhood elevated blood pressure was associated with an increased risk of adult hypertension (OR, 2.01; 95% CI, 1.53-2.65), arterial stiffness (OR, 1.69; 95% CI, 1.32-2.16) and left ventricular hypertrophy (OR, 1.86; 95% CI, 1.13-3.05) (all P < 0.05). Cardiovascular risk in adults increased with increasing childhood blood pressure levels. In addition, two abnormal childhood blood pressure observations predicted an increased likelihood of hypertension in adulthood (0.77 for 2 versus 0.70 for 1 observation, P < 0.001). Our study provides strong evidence that elevated blood pressure in childhood predicts cardiovascular risk in adults. The prediction was enhanced by two observations of abnormal blood pressure in childhood compared with a single measurement. We emphasize the importance of childhood blood pressure monitoring and control in the prevention of cardiovascular diseases.

Unstably controlled systolic blood pressure trajectories are associated with markers for kidney damage in prediabetic population: results from the INDEED cohort study

Background

The association between blood pressure change and kidney damage in patients with abnormal blood glucose remains unclear. The current study aimed to identify systolic blood pressure (SBP) trajectories among the prediabetic population and to determine their association with kidney damage after a long-term follow-up.

Methods

The incidence, development, and prognosis of diabetic kidney disease (INDEED) study is nested in the Kailuan cohort study with a focus on population with diabetes and prediabetes. We screened out people with prediabetes in 2006 and with more than three SBP records from 2006 to 2014 biennially. We used the latent mixture modeling to fit five groups of trajectories of SBP. In 2016, estimated glomerular filtration rate (eGFR), urinary albumin creatinine ratio (uACR), and urinary α1-microglobulin (α1MG), transferrin and α1-acid glycoprotein were measured, and the association between SBP trajectories and these markers was analyzed by linear regression and logistic regression models.

Results

Totally, 1451 participants with prediabetes and without kidney damage were identified in 2006. Five heterogeneous SBP trajectories were detected based on the longitudinal data from 2006 to 2014, as low-stable group (n = 323), moderate-stable group (n = 726), moderate-increasing group (n = 176), moderate-decreasing group (n = 181), and high-stable group (n = 45). Linear regression analysis showed that the moderate and high SBP groups had lower eGFR, higher uACR, higher urinary α1MG, higher transferrin, and higher α1-acid glycoprotein than the low-stable group. Multivariable analysis attenuated the association but did not change the statistical significance.

Conclusions

Prediabetic patients with persistent high-level SBP trajectory or gradually increased SBP trajectory had severer kidney damage during follow-up.

Longitudinal blood pressure patterns and cardiovascular disease risk

Observational and interventional studies have unequivocally demonstrated that "present", i.e. single-occasion, blood pressure is one of the key determinants of cardiovascular disease risk. Over the past two decades, however, numerous publications have suggested that longitudinal blood pressure data and assessment of long-term blood pressure exposure provide incremental prognostic value over present blood pressure. These studies have used several different indices to quantify the overall exposure to blood pressure, such as time-averaged blood pressure, cumulative blood pressure, blood pressure trajectory patterns, and age of hypertension onset. This review summarises existing research on the association between these indices and hard cardiovascular outcomes, outlines the strengths and weaknesses of these indices, and provides an overview of how longitudinal blood pressure changes can be measured and used to improve cardiovascular disease risk prediction.KEY MESSAGESNumerous recent publications have examined the relation between cardiovascular disease and long-term blood pressure (BP) exposure, quantified using indices such as time-averaged BP, cumulative BP, BP trajectory patterns, and age of hypertension onset.This review summarises existing research on the association between these indices and hard cardiovascular outcomes, outlines the strengths and weaknesses of these indices, and provides an overview of how longitudinal BP changes can be measured and used to improve cardiovascular disease risk prediction.Although longitudinal BP indices seem to predict cardiovascular outcomes better than present BP, there are considerable differences in the clinical feasibility of these indices along with a limited number of prospective data.

Secondhand smoke exposure and higher blood pressure in children and adolescents participating in NHANES

We assessed the relationship between acute and intermittent secondhand tobacco smoke (SHS) exposure with child and adolescent blood pressure (BP). We analyzed cross-sectional data from 3579 children and adolescents aged 8-17 years participating in the National Health and Nutrition Examination Survey (NHANES) collected between 2007 and 2012, with SHS exposure assessed via serum cotinine (a biomarker for acute exposures) and urine NNAL (4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol, a biomarker for intermittent exposures). BP percentiles and z-scores were calculated according to the 2017 guidelines established by the American Academy of Pediatrics. We used weighted linear regression accounting for the complex sampling weights from NHANES and adjusting for socio-demographic and clinical characteristics. Overall, 56% of the children were non-Hispanic white with a mean age of 12.6 years. There was approximately equal representation of boys and girls. Approximately 15.9% of participants lived in homes where smoking was present. In adjusted models, an interquartile range (IQR) increase in urinary NNAL was associated with 0.099 (95% CI: 0.033, 0.16) higher diastolic blood pressure (DBP) z-score, and with a 0.094 (95% CI: 0.011, 0.18) higher systolic blood pressure (SBP) z-score. The odds of being in the hypertensive range was 1.966 (95% CI: 1.31, 2.951) times greater among children with high NNAL exposures compared to those with undetectable NNAL. For serum cotinine, an IQR increase was associated with 0.097 (95% CI: 0.020, 0.17) higher DBP z-scores, but was not significantly associated with SBP z-scores. The associations of cotinine and NNAL with BP also differed by sex. Our findings provide the first characterization of the relationship between a major tobacco-specific metabolite, NNAL, and BP z-scores in a nationally representative population of US children.

Association of uric acid in serum and urine with subclinical renal damage: Hanzhong Adolescent Hypertension Study

BACKGROUND AND OBJECTIVES

The aim of the study was to examine the associations of uric acid (UA) in blood and urine with subclinical renal damage (SRD) and its progression in a Chinese cohort.

METHODS

1) 2342 participants from our previously established cohort who were followed up in 2017 were included. Cross-sectional analysis was used to examine the relationships between serum and urinary UA and the risk of SRD. 2) A total of 266 participants were recruited from the same cohort in 2013, and followed up in 2017. Longitudinal analysis was used to determine the relationships of serum and urinary UA with progression of SRD, which was defined as urinary albumin-to-creatinine ratio (uACR) progression or estimated glomerular filtration rate (eGFR) decline.

RESULTS

In cross-sectional analysis, higher levels of uACR were associated with higher levels of serum uric acid (SUA) and urinary uric acid/creatinine ratio (uUA/Cre). Lower eGFR was associated with higher levels of SUA and fractional excretion of uric acid (FEUA) but lower uUA/Cre levels in all subjects. In addition, the multivariate-adjusted odds ratios for SRD compared with non-SRD were 3.574 (2.255-5.664) for uUA/Cre. Increasing uUA/Cre levels were associated with higher risk of SRD. In longitudinal analysis, 4-year changes of uUA/Cre and SUA were significantly associated with eGFR decline.

CONCLUSIONS

This study suggested that urinary UA excretion was significantly associated with the risk of SRD in Chinese adults. Furthermore, 4-year changes of serum and urinary UA were associated with SRD progression. These findings suggest that UA, especially urinary UA, may be used as a simple, noninvasive marker for early detection of decreased renal function in otherwise healthy subjects.