Microalbuminuria, renal dysfunction and cardiovascular complication in essential hypertension

Randomized Trial of Dietary Acid Reduction and Acid-Base Status of Patients With CKD and Normal Estimated GFR

Introduction

Modern acid-producing diets in patients with stage G3 to G5 chronic kidney disease (CKD) can cause severe acid accumulation with metabolic acidosis and less severe accumulation causing eubicarbonatemic acidosis in stages G2 to G3, each with kidney injury. The impact of these diets on acid accumulation in those with CKD but normal estimated glomerular filtration rate (eGFR) (CKD G1) is unclear.

Methods

We assessed whether acid accumulation occurs in patients with CKD and normal eGFR, and if added base-producing fruits and vegetables (F&Vs) or oral sodium bicarbonate (NaHCO3) (HCO3 -) reduces acid accumulation and/or lowers kidney injury. We randomized 153 participants with macroalbuminuric, nondiabetic, CKD stage G1 (mean eGFR = 101 ml/min per 1.73 m2) with hypertension-associated CKD to receive F&Vs in amounts to reduce dietary acid intake by 50% (F&V, n = 51), oral NaHCO3 to match alkali intake of F&V (HCO3 -, n = 51), or usual care (UC, n = 51) for 5 years. We assessed acid accumulation by comparing observed to expected increase in plasma total CO2 (PTCO2) in response to retained bicarbonate (dose - urine bicarbonate excretion) 2 hours after an oral NaHCO3 bolus.

Results

Baseline acid accumulation, eGFR, urine excretion of albumin, N-acetyl-β-D-glucosamine, and angiotensinogen were not different among groups. Five-year acid accumulation (mean [SD]) was lower in F&V (-1.2 [11.0] mmol] and in HCO3 - (-1.7 [10.8] mmol) than in UC (5.2 [10.3] mmol, P < 0.003), which is consistent with lower acid accumulation in F&V and HCO3 -. Five-year urine excretion of albumin, N-acetyl-β-D-glucosamine, and angiotensinogen were lower in F&V and HCO3 - than in UC, which is consistent with less kidney injury.

Conclusions

Dietary acid reduction reduces acid accumulation and kidney injury in patients with CKD and normal eGFR.

Reduced systemic microvascular function in patients with resistant hypertension and microalbuminuria: an observational study

Resistant hypertension (RH) may be associated with microalbuminuria (MAU), a marker of cardiovascular risk and target organ damage, and both may be related to microvascular damage. Laser speckle contrast imaging (LSCI) is an innovative approach for noninvasively evaluating systemic microvascular endothelial function useful in the context of RH with or without MAU. Microalbuminuria was defined as a urine albumin-to-creatinine ratio between 30 and 300 mg/g. Microvascular reactivity was evaluated using LSCI to perform noninvasive measurements of cutaneous microvascular perfusion changes. Pharmacological (acetylcholine [ACh], or sodium nitroprusside [SNP]) and physiological (postocclusive reactive hyperemia [PORH]) stimuli were used to evaluate vasodilatory responses. Thirty-two patients with RH and a normal urine albumin-to-creatinine ratio (RH group) and 32 patients with RH and microalbuminuria (RH + MAU) were evaluated. Compared with patients without MAU, patients with RH + MAU showed reduced endothelial-dependent systemic microvascular reactivity, as demonstrated by an attenuation of microvascular vasodilation induced by PORH. On the other hand, ACh-induced vasodilation did not differ between groups. The results also revealed reduced endothelial-independent (SNP-induced) microvascular reactivity in hypertensive patients with MAU compared with patients without MAU. In this study, there was evidence of endothelial dysfunction associated with impaired microvascular smooth muscle function in patients with RH + MAU. This may suggest that patients with RH need more intensive therapeutic strategies for the control of blood pressure to avoid further vascular damage and the resulting consequences.The study was registered at ClinicalTrials.gov ( https://register.clinicaltrials.gov ) under protocol # NCT05464849, initial release 12/07/2022.

The Importance of Cardiac Magnetic Resonance in the Assessment Risk of Cardiac Arrhythmias in Patients with Arterial Hypertension

Objectives: Arterial hypertension (AH) is one of the major risk factors for cardiovascular diseases. An association between untreated AH and arrhythmia is observed. Cardiac magnetic resonance (CMR) assesses myocardial fibrosis by detecting foci of late gadolinium enhancement (LGE). Clinical significance of LGE at the right ventricular insertion point (RVIP) is not fully established. This study aimed to assess the relationship between the presence of LGE at the RVIP determined by CMR and the incidence of arrhythmia in a group suffering from arterial hypertension. Methods: The study group consisted of 81 patients with AH (37 men and 44 women, age: 56.7 ± 7.1 years). All subjects underwent CMR and 24 h Holter ECG monitoring. Two subgroups were distinguished in the study group based on the criterion of the presence of LGE at the RVIP in CMR. The RVIP+ subgroup consisted of patients with LGE at the RVIP, while the RVIP- group consisted of patients without LGE at the RVIP. Results: The RVIP+ subgroup was characterized by higher maximum and minimum heart rates in 24 h Holter ECG recordings compared to the RVIP- subgroup (p < 0.05). The RVIP+ subgroup had a statistically significantly higher number of single premature supraventricular beats, supraventricular tachycardias, and single premature ventricular beats than the RVIP- subgroup (p < 0.05). Regression analysis documented that a longer duration of AH (counted from diagnosis) as well as the occurrence of LGE at the RVIP (assessed by CMR) are independent risk factors for arrhythmia (p < 0.05). Conclusions: Due to the possibility of detecting LGE at the RVIP, CMR may be a useful diagnostic method in estimating the risk of arrhythmias in the group of patients with AH.

Effects of dual inhibition of renin-angiotensin-aldosterone system on cardiovascular and renal outcomes: balancing the risks and the benefits

Chronic kidney disease is a worldwide health problem often burdened by severe cardiovascular complications. Hypertension represents one of the most important risk factor in affecting cardiovascular profile of chronic kidney disease patients. Since renin-angiotensin-aldosterone system plays a major role in determining cardiovascular outcome, guidelines recommend the use of renin-angiotensin-aldosteron inhibitors in order to control hypertension.

Microalbuminuria and cardiorenal risk: old and new evidence in different populations

Since the association of microalbuminuria (MAU) with cardiovascular (CV) risk was described, a huge number of reports have emerged. MAU is a specific integrated marker of CV risk and targets organ damage in patients with hypertension, chronic kidney disease (CKD), and diabetes and its recognition is important for identifying patients at a high or very high global CV risk. The gold standard for diagnosis is albumin measured in 24-hour urine collection (normal values of less than 30 mg/day, MAU of 30 to 300 mg/day, macroalbuminuria of more than 300 mg/day) or, more practically, the determination of urinary albumin-to-creatinine ratio in a urine morning sample (30 to 300 mg/g). MAU screening is mandatory in individuals at risk of developing or presenting elevated global CV risk. Evidence has shown that intensive treatment could turn MAU into normoalbuminuria. Intensive treatment with the administration of an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker, in combination with other anti-hypertensive drugs and drugs covering other aspects of CV risk, such as mineralocorticoid receptor antagonists, new anti-diabetic drugs, and statins, can diminish the risk accompanying albuminuria in hypertensive patients with or without CKD and diabetes.

Left ventricular hypertrophy and proteinuria in patients with essential hypertension in Andkhoy, Afghanistan

Left ventricular hypertrophy (LVH) and proteinuria are known as independent predictors of cardiovascular death in hypertension. However, LVH and its association with proteinuria have not been investigated in adult hypertensive patients in Afghanistan. The objective of this research was to determine the prevalence of LVH and the correlation between LVH and proteinuria among the Afghan adult hypertensive population visiting an outpatient clinic in Afghanistan. We retrospectively evaluated 789 hypertensive patients (mean age is 56 years and 46% were men) who visited the clinic between December 2014 and August 2016. Patient characteristics and laboratory and clinical findings were recorded. The rate of LVH among hypertensive patients was 54.4%. Patients with proteinuria had a significantly higher LVH percentage compared to those without proteinuria (73.2% versus 55.8%; P<0.001). There was a significant correlation between LVH and proteinuria among hypertensive patients (r=0.182, P<0.001). Based on a multivariate regression analysis, age (odds ratio [OR], 1.04; 95% confidence interval [CI], 1.02-1.05), proteinuria (OR, 1.69; 95% CI, 1.19-2.41), and female sex (OR, 0.09; 95% CI, 0.06-0.13) were significant factors. In conclusion, the prevalence of LVH was more than 50% in the Afghan adult hypertensive population. This study indicates that there is a significant relationship between LVH detected by ECG and the presence of proteinuria among such subjects.

Serum cystatin C is associated with subclinical atherosclerosis in patients with type 2 diabetes: A retrospective study

BACKGROUND

The aim of this study was to investigate the association between the serum cystatin C level and cardiovascular disease risk in patients with type 2 diabetes mellitus.

METHODS

We studied 523 patients with type 2 diabetes mellitus and calculated estimated 10-year risk of atherosclerotic cardiovascular disease (%). Subclinical atherosclerosis was defined as brachial-ankle pulse wave velocity ⩾1700 ms, indicating the presence of arterial stiffness.

RESULTS

Cystatin C level was significantly higher in the subclinical atherosclerosis group (brachial-ankle pulse wave velocity ⩾ 1700 ms) than in the non-subclinical atherosclerosis group (brachial-ankle pulse wave velocity < 1700 ms) (7.54 ± 3.15 mg/L vs 10.04 ± 5.12 mg/L, p < 0.001). Subclinical atherosclerosis was mainly determined by age, duration of diabetes and cystatin C level, but not by serum creatinine, 10-year risk of atherosclerotic cardiovascular disease score and estimated glomerular filtration rate in the multiple linear regression analysis. In addition, an increase in cystatin C level was independently associated with the risk of subclinical atherosclerosis after adjusting for age, sex, duration of diabetes, smoking, hypertension, 10-year risk of atherosclerotic cardiovascular disease risk score, serum creatinine level, total cholesterol, high-density lipoprotein cholesterol and haemoglobin A1c (odds ratio = 1.200, 95% confidence interval: 1.04-1.38, p = 0.011).

CONCLUSION

Serum cystatin C level was significantly associated with subclinical atherosclerosis. This result suggests that an increase in cystatin C level could be a valuable surrogate marker for the risk of cardiovascular disease in patients with type 2 diabetes mellitus.

A multicenter cohort study of primary hypertension in Korea: study design and interim analysis of the Korean registry of target organ damage in hypertension (KorHR)

BACKGROUND

The Korean Registry of Target Organ Damage in Hypertension aims to evaluate the clinical characteristics and prevalence of subclinical target organ damage in Korean hypertensive patients.

METHOD

This is a prospective, observational, multicenter cohort study in which 23 university hospitals participated. Since May 2013, we have enrolled 1,318 consecutive hypertensive patients without known cardiovascular disease who met the following inclusion criteria: 1) age older than 30 years and 2) the first visit to the participating hospitals was within the last 5 years.

RESULTS

The mean age was 52 ± 12 years; 62.1% were male, and 41.3% were incident hypertensives. Patients with diabetes mellitus accounted for 7.8% of the population and 43.8% had hyperlipidemia or were on statins at baseline. The mean office blood pressures were 152 ± 20/96 ± 14 mmHg for incident hypertensive patients and 129 ± 13/78 ± 10 mmHg for patients on treatment. Patients with electrocardiographic and echocardiographic left ventricular hypertrophy accounted for 18.9 and 25.6%, respectively. The mean brachial-ankle pulse wave velocity (PWV) was 1564 ± 293 m/s and 19.5% had PWV values of more than 1750 cm/s. Patients with microalbuminuria and chronic kidney disease accounted for 21 and 4%, respectively. The first prescribed class of antihypertensive medications was angiotensin converting enzyme inhibitors in 2.9%, angiotensin receptor blockers (ARBs) in 57.5%, diuretics in 7.6%, calcium channel blockers (CCBs) in 61.0%, beta blockers in 17.3%, and fixed dose combination pill in 27.8%.

CONCLUSION

Our interim analysis shows that subclinical target organ damage in hypertension is considerably present for incident or treated hypertensive patients. CCBs and ARBs were the most commonly prescribed classes of antihypertensive medications and fixed dose combination pills were actively used in Korea.

TRIAL REGISTRATION

NCT01861080. Registered 16 May 2013.

Subclinical Kidney Damage in Hypertensive Patients: A Renal Window Opened on the Cardiovascular System. Focus on Microalbuminuria

The kidney is one of the major target organs of hypertension.Kidney damage represents a frequent event in the course of hypertension and arterial hypertension is one of the leading causes of end-stage renal disease (ESRD).ESRD has long been recognized as a strong predictor of cardiovascular (CV) morbidity and mortality. However, over the past 20 years a large and consistent body of evidence has been produced suggesting that CV risk progressively increases as the estimated glomerular filtration rate (eGFR) declines and is already significantly elevated even in the earliest stages of renal damage. Data was supported by the very large collaborative meta-analysis of the Chronic Kidney Disease Prognosis Consortium, which provided undisputable evidence that there is an inverse association between eGFR and CV risk. It is important to remember that in evaluating CV disease using renal parameters, GFR should be assessed simultaneously with albuminuria.Indeed, data from the same meta-analysis indicate that also increased urinary albumin levels or proteinuria carry an increased risk of all-cause and CV mortality. Thus, lower eGFR and higher urinary albumin values are not only predictors of progressive kidney failure, but also of all-cause and CV mortality, independent of each other and of traditional CV risk factors.Although subjects with ESRD are at the highest risk of CV diseases, there will likely be more events in subjects with mil-to-moderate renal dysfunction, because of its much higher prevalence.These findings are even more noteworthy when one considers that a mild reduction in renal function is very common in hypertensive patients.The current European Society of Hypertension (ESH)/European Society of Cardiology (ESC) guidelines for the management of arterial hypertension recommend to sought in every patient signs of subclinical (or asymptomatic) renal damage. This was defined by the detection of eGFR between 30 mL/min/1.73 m² and 60 mL/min/1.73 m² or the presence of microalbuminuria (MAU), that is an amount of albumin in the urine of 30-300 mg/day or an albumin/creatinine ratio, preferentially on morning spot urine, of 30-300 mg/g.There is clear evidence that urinary albumin excretion levels, even below the cut-off values used to define MAU, are associated with an increased risk of CV events. The relationships of MAU with a variety of risk factors, such as blood pressure, diabetes and metabolic syndrome and with several indices of subclinical organ damage, may contribute, at least in part, to explain the enhanced CV risk conferred by MAU. Nonetheless, several studies showed that the association between MAU and CV disease remains when all these risk factors are taken into account in multivariate analyses. Therefore, the exact pathophysiological mechanisms explaining the association between MAU and CV risk remain to be elucidated. The simple search for MAU and in general of subclinical renal involvement in hypertensive patients may enable the clinician to better assess absolute CV risk, and its identification may induce physicians to encourage patients to make healthy lifestyle changes and perhaps would prompt to more aggressive modification of standard CV risk factors.

Prescription pattern of Chinese herbal products for hypertension in Taiwan: a population-based study

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional Chinese medicine (TCM) has been commonly used in Asia country. The aim of this study is to analyze the utilization of TCM among hypertensive patients in Taiwan.

MATERIALS AND METHODS

The use of TCM for primary hypertensive patients was evaluated using a randomly sampled cohort of 1,000,0s recruited from the National Health Insurance Research Database in 5-year period from 2006 to 2010.

RESULTS

Overall, 49.7% (n=42,586) of primary hypertension utilized TCM and 12.1% (n=5132) of them used TCM for the treatment of hypertension. Among the top 10 most frequently prescribed herbal formulae, Tian-Ma-Gou-Teng-Yin, Gout-Teng-San, Liu-Wei-Di-Huang-Wang and its derivatives were found to be the most common herbal formulae prescribed by TCM doctors for the treatment of hypertension in Taiwan.

CONCLUSION

This study showed the utilization pattern of Chinese herbal product in patients with hypertension. Further researches and clinical trials are needed to evaluate the efficacy of these Chinese formulae or its ingredients in treating hypertension.

Screening for chronic kidney disease can be of help to prevent atherosclerotic end-organ damage

Atherosclerotic damage to the kidney is one of the most prevalent causes of chronic kidney disease and ultimately kidney failure. It frequently coincides with atherosclerotic damage to the heart, the brain and the lower extremities. In fact, the severity of the damage in the various end organs runs in parallel. As damage to the kidney is easy to measure by monitoring albuminuria and eGFR, and as the early phases of kidney damage frequently precede the alarming symptomatology in the heart, brain and peripheral vasculature, we argue that the nephrologist should consider taking the lead in better organizing early detection and management of CKD. The nephrologist can guide the general practitioner and general health care workers to offer better preventive care to the subjects at risk of progressive atherosclerotic end-organ damage.

Prevalence of abnormal urinary albumin excretion in elderly people: a Spanish survey

OBJECTIVES

HERMEX is a population-based study, which tries to evaluate the prevalence of cardiovascular risk factors in the population of Extremadura, Spain. This report provides the data concerning albuminuria in the elderly people recruited in the survey.

DESIGN AND METHODS

3,402 subjects were randomly selected from the database of the Health Care System of Extremadura. The final sample included 2,813 subjects (mean age 51.2 years, 53.5 % female). Urinary albumin excretion rate (UAER) in the first morning urine sample was analyzed. Albuminuria was diagnosed when UAER (albumin-to-creatinine ratio) was ≥ 22 mg/g in men or ≥ 31 mg/g in women.

RESULTS

The prevalence of abnormal UAER in the elderly population was 10.9 % (microalbuminuria: 8.9 %; overt proteinuria: 1.8 %). The younger subjects showed a lower prevalence of microalbuminuria (3.4 %, p < 0.001). Elderly patients showed a higher prevalence of cardiovascular risk factors than the younger ones. The elderly had higher systolic blood pressure and pulse pressure than the younger ones. Furthermore, the elderly subjects had lower plasma levels of HDL cholesterol, but higher triglycerides, glucose, creatinine, and glycosylated hemoglobin; no differences were found for total and LDL cholesterol. When the prevalence of causes of microalbuminuria was compared between age groups, we found a sharp increase in diabetic and, especially, hypertensive patients in the elderly group. The multivariate analysis showed an independent association of microalbuminuria with systolic blood pressure and plasma creatinine.

CONCLUSIONS

A high prevalence of abnormal UAER in elderly people was detected in a randomly selected sample of Spanish general population. In most elderly patients, microalbuminuria was associated with high blood pressure and, less frequently, with diabetes mellitus.

Circulatory syndrome: an evolution of the metabolic syndrome concept!

The metabolic syndrome has been a useful, though controversial construct in clinical practice as well as a valuable model in order to understand the interactions of diverse cardiovascular risk factors. However the increasing importance of the circulatory system in particular the endothelium, in both connecting and controlling organ function has underlined the limitations of the metabolic syndrome definition. The proposed "Circulatory Syndrome" is an attempt to refine the metabolic syndrome concept by the addition of recently documented markers of cardiovascular disease including renal impairment, microalbuminuria, arterial stiffness, ventricular dysfunction and anaemia to more classic factors including hypertension, dyslipidemia and abnormal glucose metabolism; all of which easily measured in clinical practice. These markers interact with each other as well as with other factors such as aging, obesity, physical inactivity, diet and smoking. The final common pathways of inflammation, oxidative stress and hypercoagulability thereby lead to endothelial damage and eventually cardiovascular disease. Nevertheless, the Circulatory (MARC) Syndrome, like its predecessor the metabolic syndrome, is only a small step toward an understanding of these complex and as yet poorly understood markers of disease.

The progressive pathway of microalbuminuria: from early marker of renal damage to strong cardiovascular risk predictor

There is clear evidence that urinary albumin excretion levels, even below the cut-off values currently used to diagnose microalbuminuria, are associated with an increased risk of cardiovascular events. The relationships of microalbuminuria with a variety of risk factors, such as hypertension, diabetes and metabolic syndrome and with several indices of subclinical organ damage, may contribute, at least in part, to explain the enhanced cardiovascular risk conferred by microalbuminuria. Nonetheless, several studies showed that the association between microalbuminuria and cardiovascular disease remains when all these risk factors are taken into account in multivariate analyses. Therefore, the exact pathophysiological mechanisms explaining the association between microalbuminuria and cardiovascular risk remain incompletely understood. The simple search for microalbuminuria in hypertensive patients may enable the clinician to better assess absolute cardiovascular risk, and its identification may induce physicians to encourage patients to make healthy lifestyle changes and perhaps would prompt to more aggressive modification of standard cardiovascular risk factors.

Clinical correlates of renal dysfunction in hypertensive patients without cardiovascular complications: the REDHY study

Our study was aimed to assess the clinical correlates of different degrees of renal dysfunction in a wide group of non-diabetic hypertensive patients, free from cardiovascular (CV) complications and known renal diseases, participating to the REDHY (REnal Dysfunction in HYpertension) study. A total of 1856 hypertensive subjects (mean age: 47+/-14 years), attending our hypertension centre, were evaluated. The glomerular filtration rate (GFR) was estimated by the simplified Modification of Diet in Renal Disease Study prediction equation. A 24-h urine sample was collected to determine albumin excretion rate (AER). Albuminuria was defined as an AER greater than 20 microg min(-1). We used the classification proposed by the US National Kidney Foundation's guidelines for chronic kidney disease (CKD) to define the stages of renal function impairment. In multiple logistic regression analysis, the probability of having stage 1 and stage 2 CKD was significantly higher in subjects with greater values of systolic blood pressure (SBP) and with larger waist circumference. SBP was also positively related to stage 3 CKD. Stage 3 and stages 4-5 CKD were inversely associated with waist circumference and directly associated with serum uric acid. Age was inversely related to stage 1 CKD and directly related to stage 3 CKD. The factors associated with milder forms of kidney dysfunction are, in part, different from those associated with more advanced stages of renal function impairment.

The association of microalbuminuria with aortic stiffness is independent of C-reactive protein in essential hypertension

BACKGROUND

It has not been fully elucidated whether microalbuminuria (MAU) and high-sensitivity C-reactive protein (hsCRP) are associated with aortic distensibility independently of each other. Our study was aimed to evaluate the independent relationships of urinary albumin excretion rate (AER) and hsCRP with aortic stiffness in hypertensive patients.

METHODS

We enrolled 140 untreated nondiabetic essential hypertensives (mean age: 48 +/- 12 years). In all subjects, 24-hour AER and plasma levels of hsCRP were determined by immunoenzymatic assay. MAU was defined as an AER of 20-200 microg/min. Aortic stiffness was assessed by measurement of carotid-femoral pulse wave velocity (PWV).

RESULTS

Carotid-femoral PWV, adjusted for age and mean arterial pressure (MAP), was higher in subjects with MAU (n = 41) than in those without it (n = 99) (11.6 +/- 2.3 vs. 9.9 +/- 1.8 m/s; P < 0.001) and in subjects with hsCRP above the median value when compared to those with lower levels of hsCRP (10.8 +/- 2.1 vs. 10 +/- 2.1 m/s; P = 0.026). In multiple regression analysis, AER and hsCPR remained independent predictors of aortic stiffness (beta = 0.24; P < 0.001 and beta = 0.15; P = 0.03, respectively).

CONCLUSIONS

Our results suggest that in patients with essential hypertension, MAU and CRP are independently associated with an increased aortic stiffness.

Hypertension and microalbuminuria: the new detrimental duo

Excretion of albumin with urine (UAE) in small amounts, i.e. microalbuminuria (MAU), also referred to as "incipient nephropathy", has long been considered a marker of early nephropathy and increased cardiovascular risk in the specific setting of diabetes mellitus. However, numerous clinical studies found an association between MAU and other cardiovascular risk factors, target organ damage and risk of cardiovascular disease in clinical contexts different from diabetes and including arterial hypertension. The present article reviews the available evidence on the clinical value of MAU in subjects with primary hypertension. In these subjects, prevalence of MAU varied from about 4% to 46% across different studies and these differences may be explained by the huge intra-individual variability in UAE, discrepancies in the technique of measurement and different definitions of MAU. A direct and continuous association between UAE and blood pressure (BP) has been found in many studies. A continuous association between UAE and left ventricular mass has also been found in most studies. In contrast, it is not yet clear whether the association between UAE and other factors including age, gender, smoking, ethnicity, insulin resistance, lipids and obesity is independent or mediated by confounders, particularly BP. From a prognostic standpoint, several longitudinal studies showed an association between MAU and the risk of future cardiovascular disease. Of particular note, in some of these studies the incidence of major cardiovascular events progressively increased with UAE starting below the conventional MAU thresholds. Thus, besides being a direct risk factor for progressive renal damage, MAU can be considered a marker, which integrates and reflects the long-term level of activity of several other detrimental factors on cardiovascular system. Antihypertensive treatment reduces UAE and such effect may be detected after just a few days of treatment. Among available antihypertensive drugs, angiotensin-converting enzyme (ACE) inhibitors and the angiotensin II receptor antagonists seem to be superior to other antihypertensive drugs in reducing UAE. The dual blockade of the renin-angiotensin system with an ACE inhibitor and an angiotensin II receptor antagonist is a new and promising approach to control UAE in hypertensive patients. Determination of MAU is recommended in the initial work-up of subjects with primary hypertension.

Incidence of microalbuminuria in hypertensive patients

The prevalence of microalbuminuria was assessed in 174 albustix negative hypertensive patients by estimating albumin in the morning random urine samples by immunoturbidimetric method within four hours of voiding of urine. The urine samples were not stored and collected without any preservatives. The urinary albumin was calculated in terms of ratio with respect to urinary creatinine and expressed as albumin creatinine ratio (mg/g). Out of 174 albustix negative hypertensives, 58 (33.3%) patients were found to have microalbuminuria. The prevalence of microalbuminuria in males and females was found to be 34% and 30.7% respectively. No correlation was found between the Body Mass Index (BMI) and albumin excretion (r(2) = 0.0271) and between duration of hypertension and urinary albumin excretion (r(2) = 0.0042). Prevalence of microalbuminuria in nonsmokers and non-alcoholic hypertensives was 20%. The prevalence in alcoholics, smokers and both smokers and alcoholics was found to be 35%, 42% and 41% respectively. The high prevalence of microalbuminuria than the various reported studies on the subject demands establishment of a screening programme for microalbuminuria, implementation of specific intervention methods and education of hypertensive patients about the consequences of smoking and alcohol on possible involvement of renal system.

Prevention of chronic kidney disease: the next step forward!

The incidence of end stage renal disease in patients who have not experienced a classic primary renal disease is dramatically increasing. Chronic kidney disease (CKD) in these patients is due to diabetes, mostly type 2, hypertension and generalised atherosclerosis. As these patients are frequently diagnosed as having renal function impairment only in the late phase, more effort should be undertaken to diagnose them earlier, that is, at a time when renoprotective measures can still be undertaken. For that purpose, measurement of the estimated glomerular filtration rate (GFR) might be helpful. To properly interpret those measurements, however, we need to be aware of the pros and cons of the use of formulas to estimate the GFR. Most likely, a better way to detect subjects at risk of CKD in the early phase is screening by dipstick proteinuria or preferably by testing for (micro-) albuminuria. Because microalbuminuria not only indicates increased renal but also enhanced cardiovascular risk, the benefits of such screening programmes may have a much greater affect than only preventing renal disease.

Microalbuminuria and early endothelial activation in essential hypertension

We hypothesized that in essential hypertensive patients (EHs), plasma levels of pro-atherogenic adhesion molecules would be increased and related with urine albumin excretion (UAE). Thus, this study was aimed at evaluating biochemical markers of endothelial activation and their relationship with UAE in a group of patients with uncomplicated EH. In basal condition soluble forms of adhesion molecules intercellular adhesion molecule (ICAM)-1 and vascular cell adhesion molecule (VCAM)-1, as well as 24-h UAE were assayed. One hundred patients with essential hypertension and no diabetes or ultrasonographic evidence of atherosclerosis were included in the study. Seventy normotensive healthy subjects served as controls. EHs were first studied overall, than were divided into two subgroups: those with UAE > or =20 mcg/min MAUs and those with UAE <20 mcg/min (non-MAUs). ICAM-1 (P<0.001) and VCAM-1 (P<0.0001) plasma concentrations were higher in EHs than in controls. Microalbuminuric EHs had greater levels of adhesion molecules than non-MAUs (ICAM-1 P=0.04; VCAM-1 P=0.02, respectively). In EHs UAE was correlated with ICAM-1 (r=0.29, P=0.003), and VCAM-1 (r=0.30, P=0.002). These associations were confirmed in multiple regression models (P=0.02 for both ICAM-1 and VCAM-1) including, along with adhesion molecules, age, body mass index and blood pressures. Our findings show that in essential hypertension there is a very early activation of endothelial adhesion molecules favouring atherosclerosis.

Effects of blood pressure lowering and metabolic control on systolic left ventricular function in Type II diabetes mellitus

Decreased left ventricular long-axis function may be the earliest stage in subclinical heart failure in Type II diabetes. To assess whether a decrease in SBP (systolic blood pressure) or a change in metabolic control would improve the long-axis function, 48 Type II diabetic patients participating in the CALM II (Candesartan and Lisinopril Microalbuminuria II) study were included in the present study. Patients were examined with tissue Doppler echocardiography at baseline and after 3 and 12 months of follow-up. Corresponding blood pressure, fructosamine and HbA(1c) (glycated haemoglobin) values were obtained. During the follow-up period, a decrease in SBP of 8 mmHg was seen (from 141+/-11 mmHg at baseline to 133+/-12 mmHg; P<0.001) and the peak systolic strain rate was significantly improved (from -1.10+/-0.25 at baseline to -1.25+/-0.22; P<0.01). There was a highly significant relationship between the changes in systolic strain rate, HbA(1c) (P<0.001) and fructosamine (P<0.05), and similarly to changes in left ventricular mass (P<0.05), whereas the correlation to the SBP reduction was not significant. Patients with improved glycaemic control, defined as a reduced HbA(1c) value after 12 months of follow-up, had a significantly improved strain rate (from -1.07+/-0.3 s(-1) at baseline to -1.32+/-0.25 s(-1); P<0.01) compared with patients with increases in HbA(1c) (from -1.14+/-0.25 s(-1) at baseline to -1.16+/-0.27 s(-1); P=not significant). The two groups had comparable baseline values of SBP, left ventricular mass, age and disease duration. In conclusion, changes in left ventricular systolic long-axis function are significantly correlated with changes in left ventricular mass, as well as metabolic control, in hypertensive patients with Type II diabetes mellitus.

Screening, Monitoring, and Treatment of Albuminuria: Public Health Perspectives

Microalbuminuria is an early sign of progressive cardiovascular and renal disease in individuals with and without diabetes. Despite compelling data, at present only a minority of patients with diabetes and rarely individuals without diabetes are screened for albuminuria in a systematic way. All of the criteria to implement systematic albuminuria screening are fulfilled in diabetes, and most are nearly fulfilled for microalbuminuria screening in individuals without diabetes. Because of the growing evidence that treatment of microalbuminuria in individuals without diabetes may offer a cost-effective benefit to prevent cardiovascular disease, nephrologists and other health care providers should pay more attention to the early detection and subsequent treatment of individuals with microalbuminuria.

Proteinuria and metabolic syndrome as predictors of cardiovascular death in non-diabetic and type 2 diabetic men and women

AIMS/HYPOTHESIS

Proteinuria predicts cardiovascular disease (CVD), but it is unclear whether this is explained by the association of the metabolic syndrome with proteinuria. Therefore, we investigated proteinuria and the metabolic syndrome as independent predictors of CVD death in men and women.

METHODS

The cohort comprised 574 non-diabetic men, 707 non-diabetic women, 371 diabetic men and 349 diabetic women, all free of CVD at baseline. Modified World Health Organization criteria were used to define the metabolic syndrome, and a urinary protein concentration of >or=0.1 g/l (or >or=0.2 g/l) to define proteinuria. The endpoint was CVD mortality during the 18-year follow-up.

RESULTS

Among non-diabetic men, CVD mortality per 1,000 person-years was as follows: no metabolic syndrome, no urinary protein group: 5.3; no metabolic syndrome, positive for urinary protein: 8.9; positive for metabolic syndrome, no urinary protein: 13.3; and positive for metabolic syndrome and urinary protein: 14.9. For non-diabetic women the corresponding values were: 0.9, 2.3, 4.9 and 7.9, respectively. Among diabetic men, CVD mortality per 1,000 person-years was 15.2, 32.5, 23.6 and 42.0 for the respective groups. Among diabetic women it was 25.3, 38.0, 26.3 and 40.3 (urinary protein in all cases defined as >or=0.1 g/l). In multivariate Cox models including both urinary protein and metabolic syndrome, the hazard ratios (HRs, 95% CI) of proteinuria for CVD mortality were 1.5 (0.9-2.4) in non-diabetic men, 1.8 (0.8-4.2) in non-diabetic women, 1.6 (1.0-2.6) in diabetic men and 1.6 (1.1-2.3) in diabetic women. Urinary protein as a continuous variable was associated with CVD mortality in all groups. The corresponding HRs for metabolic syndrome were: 1.6 (0.9-2.7), 4.0 (1.7-9.7), 1.5 (1.1-2.0) and 1.1 (0.8-1.5).

CONCLUSIONS/INTERPRETATION

Proteinuria predicted CVD mortality independently of the presence of metabolic syndrome in non-diabetic and diabetic subjects. Metabolic syndrome predicted CVD mortality in non-diabetic women and in diabetic men, independently of the presence of proteinuria.

Influence of metabolic syndrome on hypertension-related target organ damage

OBJECTIVES

The aim of our study was to analyse, in a wide group of essential hypertensive patients without diabetes mellitus, the influence of metabolic syndrome (MS) (defined according to the criteria laid down in the Third Report of the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults) on markers of preclinical cardiac, renal and retinal damage.

DESIGN

Cross-sectional study.

SETTING

Outpatient hypertension clinic.

SUBJECTS AND METHODS

A total of 353 young and middle-aged hypertensives, free from cardiovascular and renal diseases (and 37% of whom had MS), underwent echocardiographic examination, microalbuminuria determination and non-mydriatic retinography.

RESULTS

When compared with subjects without MS, hypertensive patients with MS exhibited more elevated left ventricular (LV) mass (either normalized by body surface area or by height elevated by a power of 2.7), higher myocardial relative wall thickness, albumin excretion rate (AER) and a greater prevalence of LV hypertrophy (57.7% vs. 25.1%; P < 0.00001), of microalbuminuria (36.2% vs. 19.3%; P = 0.002) and of hypertensive retinopathy (87.7% vs. 48.4%; P < 0.00001). These results held even after correction for age, 24-h blood pressures, duration of hypertension, previous antihypertensive therapy, and gender distribution. The independent relationships between LV mass and MS, and between AER and MS, were confirmed in multivariate regression models including MS together with its individual components.

CONCLUSIONS

MS may amplify hypertension-related cardiac and renal changes, over and above the potential contribution of each single component of this syndrome. As these markers of target organ damage are well-known predictors of cardiovascular events, our results may partly explain the enhanced cardiovascular risk associated with MS.

Essential hypertension, progressive renal disease, and uric acid: a pathogenetic link?

Hypertension and hypertension-associated ESRD are epidemic in society. The mechanisms responsible for renal progression in mild to moderate hypertension and those groups most at risk need to be identified. Historic, epidemiologic, clinical, and experimental studies on the pathogenesis of hypertension and hypertension-associated renal disease are reviewed and an overview/hypothesis for the mechanisms involved in renal progression is presented. There is increasing evidence that hypertension may exist in one of two forms/stages. The first stage, most commonly observed in early or borderline hypertension, is characterized by salt-resistance, normal or only slightly decreased GFR, relatively normal or mild renal arteriolosclerosis, and normal renal autoregulation. This group is at minimal risk for renal progression. The second stage, characterized by salt-sensitivity, renal arteriolar disease, and blunted renal autoregulation, defines a group at highest risk for the development of microalbuminuria, albuminuria, and progressive renal disease. This second stage is more likely to be observed in blacks, in subjects with gout or hyperuricemia, with low level lead intoxication, or with severe obesity/metabolic syndrome. The two major mechanistic pathways for causing impaired autoregulation at mild to moderate elevations in BP appear to be hyperuricemia and/or low nephron number. Understanding the pathogenetic pathways mediating renal progression in hypertensive subjects should help identify those subjects at highest risk and may provide insights into new therapeutic maneuvers to slow or prevent progression.

The Frequency of Combined Target Organ Damage and the Beneficial Effect of Ambulatory Blood Pressure Monitoring in Never Treated Mild-to-Moderate Hypertensive Patients

The aim of this study was to determine the frequency of target organ damage (TOD) and the beneficial properties of ambulatory blood pressure monitoring (ABPM) for detecting patients who are at high risk for TOD and cardiovascular disease in never treated mild-to-moderate hypertension. Sixty-seven patients (28 males and 39 females, mean age, 49.6 +/- 9.5 years) were divided into two groups, dippers (group I, n = 43) and nondippers (group II, n = 24), according to nocturnal blood pressure (BP) reduction of less than 10%. The groups were compared with respect to demographic and laboratory data and the signs of TOD (microalbuminuria, left ventricular hypertrophy, and retinopathy). We also tested the relationship between ABPM and clinic BP findings with TOD. Group I had significantly lower values than group II for serum fibrinogen (0.28 +/- 0.06 versus 0.32 +/- 0.06 g/L, P = 0.02), uric acid (0.18 +/- 0.05 versus 0.25 +/- 0.11 mmo/L, P = 0.01), urinary sodium excretion (133.7 +/- 45.2 versus 161.8 +/- 52.2 mmol/L, P = 0.02), urinary albumin excretion (17.5 +/- 14.2 versus 31.3 +/- 19.7 mg/24-h, P = 0.001), left ventricular mass index (111.8 +/- 31.0 versus 128.7 +/- 36.6 g/m(2), P = 0.05), and the prevalence of hypertensive retinopathy (51% versus 83%, P = 0.01). The frequency of the combination of all three signs of TOD (microalbuminuria, left ventricular hypertrophy, and hypertensive retinopathy) was higher in nondippers than in dippers (71.4% versus 30%, P = 0.04). We suggest ABPM may provide clinical information to detect patients prone to develop cardiovascular risks and TOD in newly diagnosed mild-to-moderate hypertension.

From secondary to primary prevention of progressive renal disease: The case for screening for albuminuria

Many subjects nowadays present with end-stage renal failure and its attendant cardiovascular complications without known prior renal damage. In this report we review the evidence available to strongly suggest that the present practice of secondary prevention in those with known prior renal disease should be extended to primary prevention for those subjects in the general population who are at risk for progressive renal failure, but who had never suffered from a primary renal disease. We show that such subjects can be detected by screening for albuminuria. Elevated urinary albumin loss is an indicator not only of poor renal, but also of poor cardiovascular prognosis. In addition to diabetic subjects who are at risk for albuminuria, we also show that hypertensive, obese, and smoking subjects are more susceptible. We suggest that therapies that have been shown to lower albumin excretion, such as ACE inhibitors, angiotensin II receptor antagonists, and statins be started early in such patients to prevent them from developing clinical renal disease and its attendant cardiovascular complications.

Relationship between albumin excretion rate and aortic stiffness in untreated essential hypertensive patients

OBJECTIVES

To evaluate, in a group of nondiabetic essential hypertensive patients with normal renal function, the relationship between albumin excretion rate (AER) and carotid-femoral pulse wave velocity (PWV), as an index of aortic stiffness.

DESIGN

Cross-sectional study.

SETTING

Outpatient hypertension clinic.

SUBJECTS

Seventy patients with mild-to-moderate essential hypertension, aged 42 +/- 8 years, never pharmacologically treated. All subjects underwent routine laboratory tests, 24-h ambulatory blood pressure (BP) monitoring, measurement of carotid-femoral PWV, by means of a computerized method, and AER.

RESULTS

Microalbuminuric patients (AER > or = 20 microg min(-1); n = 19), when compared with normoalbuminuric subjects, showed more elevated 24-h BP (136/88 +/- 10/10 vs. 128/83 +/- 7/6 mmHg; P < 0.001 and P = 0.013, for systolic and diastolic BP respectively) and higher values of carotid-femoral PWV (10.4 +/- 2 m s(-1) vs. 9.2 +/- 1.3; P = 0.006). This latter difference remained statistically significant, even after correction by ancova for 24-h systolic and diastolic BP, and body mass index (BMI, P = 0.016). Univariate regression analysis disclosed a tight correlation between AER and carotid-femoral PWV (r = 0.42; P = 0.0003). This association was confirmed in a multiple regression model (beta = 0.35; P = 0.009) in which, as independent variables, besides PWV, 24-h BP, age, serum glucose values, smoking status, gender and BMI, were added.

CONCLUSIONS

Our results seem to confirm that microalbuminuria may represent the early renal manifestation of a widespread vascular dysfunction, and therefore it is an integrated marker of cardiovascular risk.

C-Reactive Protein Modifies the Relationship Between Blood Pressure and Microalbuminuria

C-reactive protein (CRP) and microalbuminuria reflect intimately related components of the atherosclerotic disease process. Epidemiological studies found only modest associations between CRP and microalbuminuria. Blood pressure, one of the components of the metabolic syndrome in the general population, is the main determinant of microalbuminuria in diabetes and hypertension. We questioned whether CRP modifies the relationship of blood pressure and other cardiovascular risk factors with microalbuminuria in a cross-sectional study in 8592 inhabitants from Groningen, The Netherlands. The crude data showed an increase in the prevalence of microalbuminuria with increasing CRP quartiles (4.8, 9.6, 14.5, and 18.6%, P<0.0001). On stratification for cardiovascular risk factors, the data revealed a significant and positive interaction between mean arterial pressure (MAP) and quartiles of CRP with respect to the risk of microalbuminuria (Wald statistic 9.2, P=0.03). In subjects with a MAP <90 mm Hg, a nonsignificant trend in the association between CRP quartiles and microalbuminuria was found (prevalence: 3.9%, 5.8%, 6.6%, 8.7%; P=0.11). This trend was much steeper and significant in subjects with an MAP >90 mm Hg (prevalence: 6.7%, 13.6%, 20.4%, 25.1%; P<0.0001). Controlling for other risk factors in multivariate analyses, the positive interaction persisted (P=0.0004). No significant interactions between other risk factors and CRP with respect to the risk of microalbuminuria were encountered. Thus, CRP modifies the relation between blood pressure and microalbuminuria.

Microalbuminuria in diabetic and hypertensive patients and the general population--consequences of various diagnostic criteria--the Nord-Trøndelag Health Study (HUNT)

OBJECTIVE

The purpose of this paper was to study the prevalence of microalbuminuria (MA) in males and females of various ages by applying various diagnostic criteria. Three groups of subjects were studied: apparently healthy individuals; self-reported hypertensives; and diabetics.

MATERIAL AND METHODS

A total of 9255 individuals (age > or =20 years), all of whom were identified from the large (n = 65 258) population-based Nord-Trøndelag Health Study (HUNT) performed in Norway between 1995 and 1997, delivered three morning urine samples for MA analysis. Of these individuals, 651 reported both diabetes and treated hypertension, 944 diabetes only and 5547 treated hypertension only. The remaining 2113 subjects without diabetes or treated hypertension were randomly selected. The albumin:creatinine ratio (ACR) was used as an expression of urine albumin excretion.

RESULTS

Applying the classical definition of MA of ACR > or =2.5 mg/mmol in at least two out of three urine samples, the prevalence of MA in those with both diabetes and hypertension was 42.2% in males and 25.9% in females; corresponding values for those with diabetes only were 27.8% and 22.4%, for the hypertensives 19.3% and 11.5% and for the randomly selected sample 5.2% and 4.7%. The prevalence of MA increased strongly with increasing age for both genders in all subgroups. The prevalence of MA changed considerably when applying different cut-off values of ACR and at least one, two or three urine samples with ACRs above the cut-off value.

CONCLUSIONS

This study, one of the largest cross-sectional screening studies of MA ever performed, clearly illustrates the consequences of applying different diagnostic criteria. The optimal cut-off levels of MA for the prediction of cardiovascular disease still remain to be properly defined, and more follow-up studies are therefore needed.

Is it time to measure microalbuminuria in hypertension?

Former guidelines on hypertension never made a commitment to the detection of microalbuminuria for screening or follow-up of hypertensive patients. On the other hand, growing evidence support the contributory role of microalbuminuria in the prediction of absolute cardiovascular risk in hypertension and document the potential relevance of this parameter to the initial choice of antihypertensive treatment. Upcoming new guidelines and diagnostic algorithms in hypertension need to underscore the clinical positioning of microalbuminuria for stratification of risk and follow-up purposes.

C-reactive protein is associated with renal function abnormalities in a non-diabetic population

BACKGROUND

C-reactive protein (CRP) has recently been introduced in cardiovascular medicine as a predictor of myocardial infarction, stroke and peripheral artery disease in different populations. We hypothesized that elevated CRP levels are associated with renal function abnormalities.

METHODS

To test this hypothesis, we studied the relationship between CRP levels and renal function loss measured as diminished creatinine clearance in a large non-diabetic population (7317 subjects). In addition, the associations and confounding effects of established renal risk factors that could explain the association between CRP and diminished renal filtration were studied. Also, the association of CRP with early alterations in renal function, such as those evidenced by a relatively high glomerular filtration ("hyperfiltration"), was examined. CRP levels were divided in quartiles. Subjects with CRP levels within the first quartile were defined as the reference group. Diminished renal filtration and hyperfiltration were defined as a creatinine clearance below or exceeding two times the prediction interval of the age- and sex-related reference group.

RESULTS

Elevated CRP levels were positively associated with cardiovascular and renal risk factors: age, body mass index, blood pressure, serum cholesterol level, smoking, plasma glucose level and elevated urinary albumin excretion. Elevated CRP was positively associated with diminished filtration (OR 1.8; 95% CI 1.2 to 2.6). In multivariate analyses, CRP was independently associated with a diminished filtration (OR 1.9; 95% CI 1.3 to 2.9). Interestingly, CRP also was associated with hyperfiltration (highest quartile, OR 1.7; 95% CI 1.2 to 2.5). However, body mass index accounted for most of the relationship between CRP and hyperfiltration.

CONCLUSIONS

As in cardiovascular disease, CRP appears to be a risk marker for renal function loss. The mechanism of this relationship remains to be clarified. However, the association between CRP, body weight, and a relatively elevated creatinine clearance is a hypothesis-generating finding, suggesting that early inflammatory processes related to high body fat may predispose the kidney to glomerular hyperfiltration-related renal function loss.

Microalbuminuria and Cardiovascular Events in Elderly Hypertensive patients without Previous Cardiovascular Complications

To assist in the development of better treatments for elderly hypertensive patients, we studied the degree to which the baseline values of urinary albumin excretion (UAE) and other cardiovascular risk factors were predictive of cardiovascular complications in a cohort of elderly hypertensive patients. In 1994, we adopted 144 elderly hypertensive patients, who had been treated for more than 6 years at various clinics and more than 1 year at the National Cardiovascular Center, Osaka, Japan. They were divided into 2 groups: a NA group (n=111) with normoalbuminuria (UAE<30mg/day) and an MA group (n=33) with microalbuminuria (UAE 30-300 mg/day). At baseline, the two groups were similar with respect to systolic and diastolic blood pressure (SBP/DBP), pulse pressure (PP), age, ratio of males to females, serum creatinine, uric acid, total cholesterol, fasting plasma glucose (FPG), and creatinine clearance (CCr). PP was calculated as SBP minus DBP. The efficacy of blood pressure (BP) control was similar in both groups during the 8-year follow up period; however, a total of 14 cardiovascular events occurred in the MA (6/33) and NA (8/111) groups, with the MA group showing the higher incidence rate by multiple logistic regression analysis (p<0.05). At 8 years of follow-up, PP and age were correlated with UAE (p<0.05, p<0.001). At the same time point, CCr was correlated with UAE at baseline (p<0.05). The results indicated that, in elderly hypertensive patients without previous cardiovascular complications, microalbuminuria can be a predictor of cardiovascular events irrespective of conventional BP control.

Association between Left Ventricular Diastolic Dysfunction and Renal Hemodynamic Change in Patients with Treated Essential Hypertension

The heart and kidneys are important target organs in hypertension. Early signs of hypertensive target organ damage can be detected by evaluating left ventricular (LV) diastolic function and intrarenal hemodynamics using Doppler ultrasonography. However, it has not been sufficiently clarified whether cardiac damage and renal impairment progress in parallel, especially from the early stage. In the present study, Doppler echocardiography and renal Doppler ultrasonography were performed in 99 patients with treated essential hypertension, and LV diastolic filling parameters, ie., the velocity ratio of atrial filling to early diastolic filling (A/E), and the deceleration time of the E wave (DcT) and renal Doppler parameters, i.e., the diastolic to systolic ratio (D/S) and resistance index (RI), were determined. D/S was negatively correlated and RI was positively correlated with A/E and DcT. These cardiac and renal Doppler parameters were also associated with age, diastolic blood pressure, creatinine clearance, and/or glucose levels. By multiple regression analysis, D/S was found to have a significant association with DcT, independent of other clinical parameters, including age. In subgroup analysis in which patients were divided by their glucose tolerance, a significant correlation between renal Doppler parameters and LV diastolic function was observed in subjects with normal glucose tolerance, but this correlation disappeared in those with impaired glucose tolerance and diabetes mellitus. The present findings show that there is a significant relation between LV diastolic function and renal Doppler parameters in treated hypertensive patients, and suggest that cardiac damage progresses in parallel with renal involvement in these patients from the early stage.

Abolition of hypertension-induced end-organ damage by androgen receptor blockade in transgenic rats harboring the mouse ren-2 gene

A sexual dimorphism in hypertension has been observed in both human and laboratory animal studies. The mechanisms by which male sex hormones regulate cardiovascular homeostasis are still not yet fully understood and represent the subject of this study. The possible involvement of androgen receptors in the development of hypertension and end-organ damage in transgenic rats harboring the mouse Ren-2 renin gene [TGR(mREN2)27] was studied. Male TGR(mREN2)27 rats were treated with the androgen receptor antagonist Flutamide starting at 4 wk of age. Also, an androgen receptor mutation (testicular feminization mutation [tfm]) was introduced in these rats by crossbreeding male TGR(mREN2)27 rats with tfm rats. The resulting offspring male rats that contain the tfm mutation are insensitive to androgens. Flutamide treatment or tfm mutation produced a significant attenuation of the development of hypertension. Besides a reduction in cardiac hypertrophy, urinary albumin excretion was blunted and no histologic characteristics of end-organ damage were observed in the kidney after Flutamide treatment. Testosterone levels increased 15-fold after Flutamide treatment and 2.7-fold by the tfm mutation. Also, plasma estrogens and luteinizing and follicle-stimulating hormones were significantly increased. Plasma renin concentrations and activity but not plasma angiotensinogen were reduced. Our results indicate that androgens contribute not only to the development of hypertension, but even more importantly to end-organ damage in TGR(mREN2)27 rats.

Microalbuminuria, cardiovascular disease and risk factors in a nondiabetic/nonhypertensive population. The Nord-Trøndelag Health Study (HUNT, 1995-97), Norway

OBJECTIVE

Microalbuminuria (MA) as an independent marker of cardiovascular morbidity and mortality in nondiabetic/nonhypertensive individuals is under international debate. The aim of this study was to investigate the associations between MA and known cardiovascular risk factors/markers and disease in a randomly selected nondiabetic/nonhypertensive sample.

DESIGN

Cross-sectional study.

SETTING

Participants in the population-based Nord-Trøndelag Health Study (HUNT), Norway (n = 65 258).

SUBJECTS

A total of 2113 individuals (> or =20 years), randomly selected without diabetes and treated hypertension, delivered three morning urine samples for MA analysis.

MAIN OUTCOME MEASURES

MA expressed as albumin-to-creatinine ratio (ACR), cardiovascular risk factors and disease.

RESULTS

Increasing age, pulse pressure, systolic (SBP) and diastolic blood pressure (DBP) and coronary heart disease (CHD) significantly predicted MA in men and increasing pulse pressure, SBP and DBP were associated with MA in women, adjusted for other cardiovascular risk factors/markers. After excluding individuals with known CHD and untreated hypertension (SBP > or = 140 mmHg, DBP > or = 90 mmHg) and hence a high total risk of cardiovascular disease (CVD), only increasing age was associated with ACR in men and increasing SBP and pulse pressure in women. Smoking, elevated lipid and glucose levels were strongly associated with MA in individuals with a high total risk of CVD than in individuals with a low total risk.

CONCLUSION

MA was associated with increasing blood pressure in both genders, age and CHD in men. Other cardiovascular risk factors/markers might be more influential in predicting ACR variation in nondiabetic/nonhypertensive individuals with a high total risk of CVD than in individuals with a low total risk.

Relationship between microalbuminuria and cardiac structural changes in mild hypertensive patients

The aim of this study was to determine the relationship between urinary albumin excretion (UAE), cardiac structural changes upon echocardiography and 24-h ambulatory blood pressure (ABPM) levels. Twenty mild hypertensive patients (mean age 56.8 +/- 9.6 years) were evaluated. After 2 weeks of a washout period of all antihypertensive drugs, all patients underwent an echocardiographic evaluation, a 24-h ABPM and an overnight urine collection. Systolic and diastolic blood pressure during 24-h ABPM was 145 +/- 14/91 +/- 10 mmHg (daytime) and 130 +/- 14/76 +/- 8 mmHg (nighttime), respectively. Seven (35%) patients presented UAE > or = 15 microg/min, and for the whole group, the geometric mean value for UAE was 10.2 x// 3.86 microg/min. Cardiac measurements showed mean values of interventricular septum thickness (IVS) of 11 +/- 2.3 mm, left ventricular posterior wall thickness (PWT) of 10 +/- 2.0 mm, left ventricular mass (LVM) of 165 +/- 52 g, and left ventricular mass index (LVMI) of 99 +/- 31 g/m2. A forward stepwise regression model indicated that blood pressure levels did not influence UAE. Significant correlations were observed between UAE and cardiac structural parameters such as IVS (r = 0.71, P<0.001), PWT (r = 0.64, P<0.005), LVM (r = 0.65, P<0.005) and LVMI (r = 0.57, P<0.01). Compared with normoalbuminuric patients, those who had microalbuminuria presented higher values of all cardiac parameters measured. The predictive positive and negative values of UAE > or = 15 microg/min for the presence of geometric cardiac abnormalities were 75 and 91.6%. These data indicate that microalbuminuria in essential hypertension represents an early marker of cardiac structural damage.

Microalbuminuria in hypertension is not a determinant of insulin resistance

BACKGROUND

Microalbuminuria (MA) clusters with metabolic derangements linked to the insulin resistance syndrome, and is associated with increased risk of cardiovascular disease in both diabetes and hypertension. This study questioned if MA, reflecting endothelial damage, is directly linked to impaired insulin action.

METHODS

MA was measured in two 24-hour urine samples in 84 persons with untreated hypertension recruited from a population survey (diastolic blood pressures 90 to 105 mm Hg). Thirty-one percent had MA values>20 microg/min (MA group, N = 26), and these were matched according to age, gender, and body-mass index with hypertensive persons without MA (non-MA group, N = 32) for comparison of the metabolic profile. Insulin sensitivity was measured with clamp techniques.

RESULTS

The MA and non-MA groups were similar in their fasting and post-load glucose and insulin levels, in the first (930 +/- 594 vs. 1097 +/- 707 pmol/L) and second (1111 +/- 662 vs. 1163 +/- 702 pmol/L) phases of insulin release during a hyperglycemic clamp, and in their insulin sensitivity indices (0.16 +/- 0.10 vs. 0.17 +/- 0.13, P> 0.3 for all). The MA group had higher systolic blood pressure (157 +/- 13 vs. 150 +/- 12 mm Hg, P = 0.05) and a higher serum level of circulating advanced glycation end products (AGEs; 11.0 +/- 3.0 vs. 7.9 +/- 3.5 U/mL, P = 0.05) than the controls. No associations were found between MA and the insulin sensitivity index, or glucose and insulin levels. Weak associations were found with systolic blood pressure (r = 0.25, P = 0.05), AGEs (r = 0.27, P = 0.05), and smoking habits (r = 0.39, P = 0.01).

CONCLUSION

In hypertension, MA is not a determinant of insulin resistance, provided confounding factors such as degree of adiposity are carefully controlled.

Microalbuminuria is associated with unfavourable cardiac geometric adaptations in essential hypertensive subjects

We sought in this study to examine the relationship between microalbuminuria and cardiac geometry since a slight increased urinary albumin excretion (UAE) and increased left ventricular (LV) mass have both been identified as predictors of cardiovascular events in hypertensive subjects. For this purpose, microalbuminuria was determined in three non-consecutive 24-h urine samples as UAE of 20-200 mg/24 h in a group of 249 untreated hypertensive subjects. Echocardiographic classification of patients into LV geometric patterns was based on relative wall thickness values and on gender-specific values for LV mass index (LVMI). The group of patients with microalbuminuria (n = 119) was matched for age, sex, body mass index, smoking status and plasma cholesterol level with the group of patients without microalbuminuria (n = 130). Subjects with microalbuminuria had significantly increased LVMI (111 vs 90 g/m(2), P < 0.0001), relative wall thickness (0.46 vs 0.41, P < 0.001) and office systolic and diastolic blood pressure (161 vs 148 and 101 vs 97 mmHg, respectively, P < 0.005). For the pooled population, UAE was positively correlated to LVMI (r = 0.46, P < 0.001) and relative wall thickness (r = 0.47, P < 0.001). In the entire population, normal LV geometry, concentric LV remodelling, eccentric and concentric LV hypertrophy was found in 34%, 33%, 12% and 21%, respectively. The prevalence of normal LV geometry was significantly higher in normoalbuminuric compared with microalbumnuric subjects (55 vs 14%, P < 0.001) while the prevalence of concentric LV hypertrophy was significantly higher in microalbuminuric compared with normoalbuminuric subjects (32 vs 5%, P < 0.0001). Multiple regression analysis revealed that concentric LV hypertrophy was significantly associated with increased values of UAE and mean arterial pressure. In conclusion, the higher prevalence of unfavourable LV geometric patterns in hypertensive subjects with microalbuminuria compared with those without microalbuminura, may account for the worse cardiovascular outcomes associated with the presence of an increased UAE in hypertensive subjects.

Correlates of pulse pressure reduction during antihypertensive treatment (losartan or atenolol) in hypertensive patients with electrocardiographic left ventricular hypertrophy (the LIFE study)

In hypertensive patients, pulse pressure has been related to hypertension-induced target organ damage and risk of cardiovascular events. However, correlates of pulse pressure reduction during antihypertensive treatment have been less extensively investigated. We related pulse pressure changes to clinical and echocardiographic findings before and after 2 years of antihypertensive treatment in 767 patients aged 55 to 80 years (mean 66) in the Losartan Intervention For End point reduction in hypertension study. Over 2 years, blood pressure and pulse pressure were reduced from 173/98 to 147/84 mm Hg and from 75 to 63 mm Hg, respectively, both p <0.001. In linear multivariate analysis controlling for initial pulse pressure, 2-year reduction in pulse pressure correlated negatively with age and concomitant diabetes mellitus, and positively with body height and 2-year reduction in mean blood pressure (multiple R(2) = 0.42, p <0.01). When dividing the study population into 2 groups using a prognostically validated partition for pulse pressure, patients with pulse pressure > or =63 mm Hg after 2 years of antihypertensive treatment (n = 349) were older and shorter, included more women and patients with isolated systolic hypertension, diabetes mellitus, albuminuria, and echocardiographic left ventricular hypertrophy at baseline, and also had a smaller decrease in mean blood pressure and the urinary albumin/creatinine ratio over 2 years (all p <0.05). Thus, in hypertensive patients with electrocardiographic left ventricular hypertrophy, older age, less reduction in mean blood pressure, concomitant diabetes mellitus, and shorter stature are associated with attenuated pulse pressure reduction during antihypertensive treatment.

Microalbuminuria, an integrated marker of cardiovascular risk in essential hypertension

This paper reviews the existing epidemiological and clinical evidence about the relationships of non-diabetic microalbuminuria with cardiovascular risk factors such as elevated blood pressure (BP), systolic particularly, cardiac hypertrophy, adverse metabolic status, smoking habits, elevated angiotensin II levels, endothelial dysfunction, acute and perhaps subclinical inflammation. Because of that unique property of reflecting the influence of so many clinically relevant parameters, microalbuminuria may legitimately be defined as an integrated marker of cardiovascular risk, an unique profile among the several prognostic predictors available to stratify risk in hypertensive patients. Recent cohort studies also showed associations with cardiovascular morbidity and mortality independently from conventional atherogenic factors. This behaviour, whose understanding still needs further elucidation, suggests to measure albuminuria and to screen patients at a higher absolute risk in whom preventive treatment is expected to be more beneficial than in those with a lower absolute risk.

Metabolic pathogenesis of cardiorenal disease

Clinical data have established microalbuminuria/proteinuria as an independent risk factor for the development and progression of renal disease in patients with either diabetes or essential hypertension. Decreased kidney function is associated with increased cardiovascular risk, even at modest reductions in estimated creatinine clearance (to approximately 60 mL/min/1.73 m(2)) or modest elevations in serum creatinine (>1.4 mg/dL). Treatment with angiotensin-converting enzyme inhibitors has been shown in clinical trials to delay or stabilize the rate of progression of renal disease. Reduction in cardiovascular events, such as stroke and myocardial infarction, also has been shown in these high-risk individuals. These effects are dependent and independent of blood pressure control, suggesting a nonhemodynamic effect in blockade of the renin-angiotensin system. In conjunction with other therapeutic interventions, such as dietary modification and control of serum lipids, it appears that for at least a subgroup of patients it is possible to delay or prevent progression of kidney failure. There frequently is a clustering of risk factors in these individuals, including insulin resistance, salt sensitivity, hypertension, and dyslipidemia. The mechanism of the relationship between albuminuria and cardiovascular disease is unclear but may be related to endothelial cell dysfunction. Nonetheless, the presence of microalbuminuria/proteinuria as a marker for cardiovascular disease has important implications for the identification and treatment of individuals at risk.

Proteinuria after renal transplantation affects not only graft survival but also patient survival

BACKGROUND

Proteinuria is associated with an increased risk of renal failure. Moreover, proteinuria is associated with an increased death risk in patients with diabetes mellitus or hypertension and even in the general population.

METHODS

One year after renal transplantation, we studied the influence of the presence of proteinuria on the risk of either graft failure or death in all 722 recipients of a kidney graft in our center who survived at least 1 year with a functioning graft. Proteinuria was analyzed both as a categorical variable (presence versus absence) and as a continuous variable (quantification of 24 hr urine). Other variables included in this analysis were: donor/recipient age and gender, original disease, race, number of HLA-A and HLA-B mismatches, previous transplants, postmortal or living related transplantation, and transplantation year. At 1 year after transplantation, we included: proteinuria, serum cholesterol, serum creatinine, blood pressure, and the use of antihypertensive medication.

RESULTS

In the Cox proportional hazards analysis, proteinuria at 1 year after transplantation (both as a categorical and continuous variable) was an important and independent variable influencing all endpoints. The influence of proteinuria as a categorical variable on graft failure censored for death showed no interaction with any of the other variables. There was an adverse effect of the presence of proteinuria on the graft failure rate (RR=2.03). The influence of proteinuria as a continuous variable showed interaction with original disease. The presence of glomerulonephritis, hypertension, and systemic diseases as the original disease significantly increased the risk of graft failure with an increasing amount of proteinuria at 1 year. The influence of proteinuria as a categorical variable on the rate ratio for patient failure was significant, and there was no interaction with any of the other significant variables (RR=1.98). The death risk was almost twice as high for patients with proteinuria at 1 year compared with patients without proteinuria. The influence of proteinuria as a continuous variable was also significant and also without interaction with other variables. The death risk increased with increasing amounts of proteinuria at 1 year. Both the risks for cardiovascular and for noncardiovascular death were increased.

CONCLUSION

Proteinuria after renal transplantation increases both the risk for graft failure and the risk for death.