Microalbuminuria in primary hypertension: a guide to optimal patient management?

Hypertension management in primary health care: a survey in eight regions of Sweden

PURPOSE

To explore hypertension management in primary healthcare (PHC).

DESIGN

Structured interviews of randomly selected PHC centres (PHCCs) from December 2019 to January 2021.

SETTING

Seventy-six PHCCs in eight regions of Sweden.

MAIN OUTCOME MEASURES

Staffing and organization of hypertension care. Methods of measuring blood pressure (BP), laboratory tests, registration of co-morbidities and lifestyle advice at diagnosis and follow-up.

RESULTS

The management of hypertension varied among PHCCs. At diagnosis, most PHCCs (75%) used the sitting position at measurements, and only 13% routinely measured standing BP. One in three (33%) PHCCs never used home BP measurements and 25% only used manual measurements. The frequencies of laboratory analyses at diagnosis were similar in the PHCCs. At follow-up, fewer analyses were performed and the tests of lipids and microalbuminuria decreased from 95% to 45% (p < 0.001) and 61% to 43% (p = 0.001), respectively. Only one out of 76 PHCCs did not measure kidney function at routine follow-ups. Lifestyle, physical activity, food habits, smoking and alcohol use were assessed in ≥96% of patients at diagnosis. At follow-up, however, there were fewer assessments. Half of the PHCCs reported dedicated teams for hypertension, 82% of which were managed by nurses. There was a great inequality in the number of patients per tenured GP in the PHCCs (median 2500; range 1300-11300) patients.

CONCLUSIONS

The management of hypertension varies in many respects between PHCCs in Sweden. This might lead to inequity in the care of patients with hypertension.

The role of Nrf2 in acute kidney injury: Novel molecular mechanisms and therapeutic approaches

Acute kidney injury (AKI) is a common clinical syndrome that is related to high morbidity and mortality. Oxidative stress, including the production of reactive oxygen species (ROS), appears to be the main element in the occurrence of AKI and the cause of the progression of chronic kidney disease (CKD) into end-stage renal disease (ESRD). Nuclear factor erythroid 2 related factor 2 (Nrf2) is a significant regulator of redox balance that has been shown to improve kidney disease by eliminating ROS. To date, researchers have found that the use of Nrf2-activated compounds can effectively reduce ROS, thereby preventing or retarding the progression of various types of AKI. In this review, we summarized the molecular mechanisms of Nrf2 and ROS in AKI and described the latest findings on the therapeutic potential of Nrf2 activators in various types of AKI.

Decreased Urinary Levels of SIRT1 as Non-Invasive Biomarker of Early Renal Damage in Hypertension

Sirtuins have become important players in renal damage in hypertension and diabetes, but their value as biomarkers is poorly assessed. The aims of the study were to evaluate the levels of sirtuin1 (SIRT1), and two miRNAs that regulate SIRT1 expression in hypertensive patients with incipient renal damage with and without diabetes. We quantified urinary SIRT1 and claudin 1 (CLDN1) mRNA and miR34-a and miR-200a levels by quantitative real-time polymerase chain reaction (RT-qPCR) from patients and in cultured podocytes treated with high glucose and angiotensin II. Western blot and fluorescence analyses were also performed. We found decreased SIRT1 levels in patients with increased urinary albumin excretion (UAE), the lowest with diabetes presence, and a strong association with UAE, discriminating incipient renal damage. In vitro experiments also showed SIRT1 overall decreases in podocyte cultures under treatment conditions. In urine samples, miR-34a was reduced and miR-200a increased, both related to UAE levels. However, both miRNAs were generally increased in podocyte cultures under high glucose and angiotensin-II treatment. These results show a significant urinary SIRT1 decrease in albuminuric hypertensive patients, strongly associated with albuminuria, suggesting that SIRT1 could be a potential and non-invasive method to assess incipient renal damage in hypertensive patients.

Cross-Sectional Relationship between Carotid-Femoral Pulse Wave Velocity and Biomarkers in Vascular-Related Diseases

Objectives

The present study was done to investigate the relationship between carotid-femoral pulse wave velocity (CFPWV) and biomarkers such as homocysteine (Hcy), N-terminal pro-brain natriuretic peptide (NT-proBNP), and urine albumin (microalbumin) (UAE) in vascular-related diseases.

Methods

656 subjects were enrolled into our study. There were 377 patients with hypertension, 231 with coronary heart disease, 154 with diabetes mellitus, and 186 healthy subjects. They were divided into four groups according to the number of suffered diseases: group 1 had only one of three diseases, group 2 had two, and group 3 had all of three diseases. CFPWV was measured by Complior apparatus.

Results

CFPWV was significantly higher in group 3 than in the healthy group, group 1, and group 2 (12.71 ± 2.38 vs 10.11 ± 2.28, 10.70 ± 2.12, and 11.92 ± 2.55, all p < 0.05). The level of Hcy was significantly higher in group1, group 2, and group 3 than in healthy subjects, respectively. Levels of Log NT-proBNP and Log UAE were significantly higher in group 3 than in group 1 (2.27 ± 0.4 vs 2.10 ± 0.4, 1.00 ± 0.65 vs 0.68 ± 0.56, both p < 0.05). Positive correlation between CFWV and Hcy, Log UAE, and Log NT-proBNP was found in the entire study group (r = 0.109, 0.196, and 0.119, all p < 0.05). Multivariate analysis showed that pulse pressure, age, fasting plasma glucose, diastolic blood pressure, body mass index, and Log UAE were independent associating factors of CFPWV in all subjects (β = 0.334, p < 0.001; β = 0.333, p < 0.001; β = 0.126, p=0.004; β = 0.137, p=0.003; β = −0.142, p=0.002; and β = 0.098, p=0.031).

Conclusions

CFPWV was significantly higher in subjects with hypertension, CHD, and DM. There was correlation between CFPWV and biomarkers such as NT-proBNP, Hcy, and urine albumin (microalbumin).

Bidirectional and Temporal Association Between Hypertension and Microalbuminuria: A Longitudinal Study in Chinese Adults

Background Although hypertension and microalbuminuria are closely interrelated, the magnitude and temporal sequence of the bidirectional association between hypertension and microalbuminuria are largely unknown. We aimed to delineate the bidirectional and temporal relationship between hypertension and microalbuminuria. Methods and Results Leveraging a longitudinal cohort of Chinese adults who had blood pressure and urinary albumin measured twice 4 years apart, we examined the temporal association between hypertension and microalbuminuria by bidirectional and cross-lagged panel analysis. All participants were free of cardiovascular disease and chronic kidney disease at baseline. Bidirectional association analysis found that baseline microalbuminuria predicted the risk of incident hypertension (odds ratio=1.75, P=0.028), and baseline blood pressure also significantly predicted the risk of microalbuminuria (odds ratios=1.27 and 1.21 for a per-SD increase in systolic and diastolic blood pressure, respectively; all P<0.05). Cross-lagged panel analysis demonstrated a bottom-line significant relationship of baseline systolic blood pressure to follow-up urinary albumin ( P=0.079), which is significantly weaker than the other direction of the relationship of baseline urinary albumin to follow-up blood pressures (all P<0.001). Conclusions These findings indicate a significant bidirectional association between microalbuminuria and hypertension in Chinese adults. Elevated urinary albumin excretion is more likely to precede hypertension. The causality between microalbuminuria and hypertension needs further investigation.

Optical coherence tomography angiography and arterial hypertension: A role in identifying subclinical microvascular damage?

INTRODUCTION

To evaluate retinal microvasculature modifications by means of optical coherence tomography angiography in human subjects diagnosed with arterial hypertension and to assess potential clinical relevance for early diagnosis.

METHODS

A cross-sectional study of 30 subjects affected by arterial hypertension compared to a matched cohort of healthy patients was conducted. Patients were evaluated by the Outpatient Clinic for Hypertension and the Retina Center, University of Insubria, Varese, Italy. Patients were divided into three groups: Group 1-healthy subjects, Group 2-patients first diagnosed with hypertension, and Group 3-patients with treated hypertension. Optical coherence tomography angiography was performed applying different analysis protocols for macula and optic disk, using an AngioVue OCTA System on an Optovue device. Morphological data were compared to and correlated with clinical vascular parameters, to evaluate preclinical microvascular damage.

RESULTS

A significant reduction in deep vascular layer density (Group 1: 59.2% ± 1.5% standard deviation; Group 2: 59.2% ± 2.2% standard deviation; Group 3: 57.8% ± 2.6% standard deviation; p < 0.05) as well as an enlargement of the deep foveal avascular zone area (Group 1: 0.34 ± 0.09 mm²; Group 2: 0.36 ± 0.07 mm²; Group 3: 0.39 ± 0.1 mm²; p < 0.05) was measured in patients with first diagnosed hypertension and in treated patients compared to healthy subjects. We also observed a significant decrease in mean foveal choroidal thickness in affected patients compared to controls (Group 1: 319.68 ± 61.72 µm standard deviation; Group 2: 251.04 ± 63.1 µm standard deviation; Group 3: 262.65 ± 51.08 µm standard deviation; p < 0.05). Our preliminary data did not show a significant correlation with microalbuminuria levels.

DISCUSSION

Retinal vascular density showed pathological modifications between healthy subjects and hypertensive patients. These preliminary findings suggest that optical coherence tomography angiography may identify pathological markers of an early hypertensive damage and help monitor disease progression with potential therapeutic advantages.

Electronic circular dichroism for the detection of microalbuminuria

Over the past decades, chiroptical spectroscopy has proved its incomparable ability to elucidate the structure and spatial arrangement of chiral molecules. Systematic analysis of biomolecules in the natural environment of biofluids, however, remains challenging. In this study, we used chiroptical spectroscopy to monitor urinary levels of human serum albumin. Not only severe proteinuria but even just a slightly increased urinary excretion of albumin (microalbuminuria) may indicate serious health complications, especially for diabetic individuals. Given the chiral nature of albumin and its typical spectral pattern, it may be easily observable by chiroptical spectroscopy, particularly electronic circular dichroism. The performed chiroptical analysis of urine not only allowed the detection of clinically confirmed microalbuminuria but was also able to reveal this pathological condition in cases beyond the diagnostic capability of common clinical procedures. Thus, our approach suggests that electronic circular dichroism is a useful tool for the fast and reliable qualitative monitoring of microalbuminuria with the potential for a quantitative analysis in the future.

A more tubulocentric view of diabetic kidney disease

Diabetic nephropathy (DN) is a common complication of Diabetes Mellitus (DM) Types 1 and 2, and prevention of end stage renal disease (ESRD) remains a major challenge. Despite its high prevalence, the pathogenesis of DN is still controversial. Initial glomerular disease manifested by hyperfiltration and loss of glomerular size and charge permselectivity may initiate a cascade of injuries, including tubulo-interstitial disease. Clinically, 'microalbuminuria' is still accepted as an early biomarker of glomerular damage, despite mounting evidence that its predictive value for DN is questionable, and findings that suggest the proximal tubule is an important link in the development of DN. The concept of 'diabetic tubulopathy' has emerged from recent studies, and its causative role in DN is supported by clinical and experimental evidence, as well as plausible pathogenetic mechanisms. This review explores the 'tubulocentric' view of DN. The recent finding that inhibition of proximal tubule (PT) glucose transport (via SGLT2) is nephro-protective in diabetic patients is discussed in relation to the tubule's potential role in DN. Studies with a tubulocentric view of DN have stimulated alternative clinical approaches to the early detection of diabetic kidney disease. There are tubular biomarkers considered as direct indicators of injury of the proximal tubule (PT), such as N-acetyl-β-D-glucosaminidase, Neutrophil Gelatinase-Associated Lipocalin and Kidney Injury Molecule-1, and other functional PT biomarkers, such as Urine free Retinol-Binding Protein 4 and Cystatin C, which reflect impaired reabsorption of filtered proteins. The clinical application of these measurements to diabetic patients will be reviewed in the context of the need for better biomarkers for early DN.

Genome-wide association studies of albuminuria: towards genetic stratification in diabetes?

Genome-wide association studies (GWAS) have been very successful in unraveling the polygenic structure of several complex diseases and traits. In the case of albuminuria, despite the large sample size achieved by some studies, results look sparse with a limited number of loci reported so far. This review searched for GWAS studies of albumin excretion, albuminuria, and proteinuria. The resulting picture sets elements of uniqueness for albuminuria GWAS with respect to other complex traits. So far, very few loci associated with albuminuria have been validated by means of genome-wide significant evidence or formal replication. With rare exceptions, the validated loci are ethnicity specific. Within a given ethnicity, variants are common and have relatively large effects, especially in the presence of diabetes. In most cases, the identified variants were functional and a biological involvement of the target genes in renal damage was established. Recently reported variants associated with albuminuria in diabetes may be potentially combined into a genetic risk score, making it possible to rank diabetic patients by increasing risk of albuminuria. Validation of this model is required. To expand the understanding of the biological basis of albumin excretion regulation, future initiatives should achieve larger sample sizes and favor a transethnic study design.

Clinical characteristics, target organ damage and associate risk factors of resistant hypertension determined by ambulatory blood pressure monitoring in patients aged ≥ 80 years

OBJECTIVES

To investigate clinical characteristics, target organ damage, and the associated risk factors of the patients aged ≥ 80 years with true resistant hypertension (RH).

METHODS

Patients aged ≥ 80 years with hypertension (n = 1163) were included in this study. The included participants attended a structured clinical examination and an evaluation of RH was carried out. The prevalence, clinical characteristics and target organ damage of patients with RH were assessed. The associated clinical risk factors were analyzed by using logistic regression.

RESULTS

The prevalence of RH diagnosis by 24-h ambulatory blood pressure monitoring assessment was 21.15%. End-diastolic left ventricular internal dimension, left ventricular mass index as well as prevalence of left ventricular hypertrophy were significantly greater in patients with RH than in control group. The common carotid artery intimal media thickness, carotid walls thickness, common carotid artery diameter and relative wall thickness were significant greater in RH group than in control. A relatively higher level of creatinine, estimated glomerular filtration rate, microalbuminuria and retinal changes was found in RH group than in control. A multivariate analysis showed that patients with a history of diabetes, higher body mass index (BMI) and lipid profiles were independent risk factors of RH.

CONCLUSIONS

The prevalence of RH in patients aged ≥ 80 years was within the range of reported rates of the general population. Subjects with RH diagnosis showed a higher occurrence of target organ damage than patients with well controlled blood pressure. Patients with diabetes, higher BMI and serum lipid profiles were independent risk factors for RH in patients aged ≥ 80 years.

Relationship between diurnal blood pressure and renal histopathological changes in white coat hypertension

BACKGROUND

Multiple epidemiological studies have clearly demonstrated the macrovascular risks associated with white coat hypertension (WCH) or sustained hypertension (SH). In patients with WCH, there is no literature available on renal histopathological changes and that on blood pressure pattern and native kidney outcome is scant. We aimed to clarify the relationship between blood pressure variables and pathological features of kidney biopsies in living kidney donors with WCH.

METHODS

This cross-sectional study included living kidney donors with WCH (n = 10) and SH (n = 10), and 20 healthy kidney donors with similar demographic features (control group). Kidney allograft biopsy samples were obtained during transplantation and chronic glomerular, vascular and tubulointertitial changes were semiquantitatively scored according to the Banff classification.

RESULTS

The mean age of the 20 hypertensive subjects (Group 1) and controls (Group 2) was 59.3 ± 8.5 versus 59.6 ± 7.6 years and almost half were female. There was no difference in renal function parameters between the groups; however, kidney histopathology in Group 1 was worse than Group 2 with a chronicity index of 2.80 ± 1.67 versus 1.75 ± 1.16 (p = 0.02). There was no difference between histopathological scores of patients with WCH or SH (chronicity index: 2.60 ± 1.43 vs. 2.70 ± 1.70, p = 0.88). Night-to-day mean arterial pressure (MAP) ratio was significantly associated with chronicity index in patients with WCH. Moreover, WCH patients with non-dipper hypertensive pattern had a worse chronicity index.

CONCLUSIONS

Significant histopathological alterations in the kidney were observed in patients with WCH and SH, and were accentuated in WCH patients with non-dipper blood pressure pattern.

Decreased Renal Function Is a Risk Factor for Subclinical Coronary Atherosclerosis in Korean Postmenopausal Women

OBJECTIVES

Decreased renal function is associated with increased cardiovascular risk. Our study was planned to verify the association of decreased renal function and subclinical coronary atherosclerosis in postmenopausal women.

METHODS

We performed a retrospective review of 251 Korean postmenopausal women who visited the health promotion center for a routine health checkup. Estimated glomerular filtration rate (eGFR) was used to show renal function, which was estimated by calculated using the Cockcroft-Gault (CG) and the modification of diet in renal disease (MDRD) formulas. Coronary atherosclerosis was assessed by 64-row multidetector computed tomography.

RESULTS

Women with reduced eGFR (< 60 mL/minute/1.73 m2) had significantly higher brachial-ankle pulse wave velocity (baPWV) than women with normal eGFR (≥ 60 mL/minute/1.73 m2). The eGFR was negatively correlated with baPWV (r = -0.352, P < 0.001), significantly. The eGFR was lower in women with coronary atherosclerosis than in normal control women, markedly. Reduced eGFR was significantly associated with the presence of coronary atherosclerosis (odds ratio [OR] = 7.528, 95% confidence interval [CI] = 2.728-20.772, P < 0.001).

CONCLUSIONS

Decreased eGFR was closely associated with increased arterial stiffness and coronary atherosclerosis in postmenopausal women. Evaluating subclinical atherosclerosis by screening the renal function in postmenopausal women may be helpful screening high risk group and considering starting menopausal hormone therapy before atherosclerosis development.