Clinical value of microalbuminuria in hypertension

Association of High Levels of Spot Urine Protein with High Blood Pressure, Mean Arterial Pressure and Pulse Pressure with the Development of Diabetic Chronic Kidney Dysfunction or Failure among Diabetic Patients. Statistical Regression Modeling to Predict Diabetic Proteinuria

INTRODUCTION

In research elevated Blood Pressure (BP) has been demonstrated to be a risk for the development of nephropathy and chronic renal disease (CKD) Or Diabetic Kidney Disease (DKD) among diabetics. However, no study has find correlation for the spot urine protein (UPr) excretion with elevated BP, Pulse Pressure (PP) and mean arterial pressure MAP). This technique was invented in the current study.

METHODS

10,270 were recruited for more than 12 years. Demographically, 43%, 38%, and 16% showed hypertension, nephropathy and chronic renal disease, respectively. UPr demonstrated significant correlations with systolic BP (SBP) and diastolic BP (DPB), MAP and PP (p < 0.0001 for all). SBP, DBP, PP and MAP, UPr were observed to be higher among the groups with nephroaphty and CKD/DKD with highly significant p-values (all p < 0.05). With logistic regression, odds ratio of hypertension (HTN) with nephropathy was observed to be 2.99 (95% CI 2.44 to 3.7; p < 0.0001); and odds ratio of HTN with CKD/DK was 7.1 (95% CI 4.3 to 11.84; p<0.0001), indicating that HTN significantly contributes to the development of nephropathy and CKD/DKD in diabetics.

RESULTS

Invented regression models for the excretion of UPr from the kidney with elevated SBP, DBP, MAP and PP were highly significant (p < 0.0001 for all); UPr = -138.6 + [1.347 × SBP] ; UPr = -93.4 + [1.62 × DBP] ; UPr = -149.5 + [1.922 × MAP] ; UPr = -41.23 +[1.541 × PP].

CONCLUSION

Current study is the first one to introduce this technique. These invented new equations can be used by physicians to estimate protein excretion in urine at bedside and outpatients departments for monitoring proteinuria and CKD/DKD.

Microalbuminuria and Retinopathy among Hypertensive Nondiabetic Patients at a Large Public Outpatient Clinic in Southwestern Uganda

BACKGROUND

Routine testing of microalbuminuria and retinopathy is not done among patients with high blood pressure in resource-limited settings. We determined the prevalence of microalbuminuria and retinopathy and their risk factors among hypertensive patients at a large hospital in western Uganda.

METHODS

We consecutively recruited nondiabetic patients with hypertension at the outpatients' clinic over a period of 3 months. Spot urine samples were tested for urine albumin. Direct fundoscopy was done to assess retinal vasculature and optic disc for signs of hypertensive retinopathy. Logistic regression was done with retinopathy and microalbuminuria as primary outcomes.

RESULTS

We enrolled 334 patients and, of these, 208 (62.3%) were females, with median age of 55 years (range: 25-90). The prevalence of microalbuminuria was 59.3% (95% CI: 50.1-72.2) and that of retinopathy was 66.8% (95% CI: 58.6-76.5). The independent correlates of retinopathy and microalbuminuria were systolic blood pressure (SBP) > 140 mmHg (OR = 2.76, 95% CI: 1.29-5.93) and treatment with beta-blockers (OR = 2.16, 95% CI: 1.05-4.44). Use of ACEIs was unrelated to the study outcomes.

CONCLUSION

The prevalence of retinopathy and microalbuminuria is high. Clinicians should aim for better control of blood pressure and routinely perform fundoscopy and urine albumin, especially for patients with poorly controlled blood pressure.

Fabry in the older patient: Clinical consequences and possibilities for treatment

Baseline demographic and phenotypic characteristics of patients aged ≥50years in the Fabry Outcome Survey (Shire; data extracted June 2014) were compared with younger adults to investigate potential factors influencing treatment decisions in later life. Age groups were defined using age at treatment initiation or at FOS entry for untreated patients: 18-49 (n=1344; 49.5% male; 64.6% received agalsidase alfa enzyme replacement therapy [ERT]); 50-64 (n=537; 35.4% male; 74.3% treated); 65-74 (n=137; 32.1% male; 68.6% treated); and ≥75years (n=26; 26.9% male; 50.0% treated). Successive age groups showed higher median age at first symptom and diagnosis. Median alpha-galactosidase A activity, measured as percentage activity of the midpoint of the normal range, was much greater in females than males of all groups except ≥75years (33.4% in females; 27.8% in males). Patients aged ≥75years showed greater values than patients aged 18-49years for median left ventricular mass indexed to height (62.7 vs 42.4g/m(2.7)), mean ventricular wall thickness (15.0 vs 10.0mm) and prevalence of hypertension (57.7% vs 21.8%), and lower median estimated glomerular filtration rate (Modification of Diet in Renal Disease: 65.6 vs 98.5mL/min/1.73m(2)). Larger proportions in the groups aged ≥50 exhibited cardiac and/or cerebrovascular manifestations compared with patients aged 18-49years. The smaller proportion of patients receiving ERT aged ≥75years compared with the younger groups might reflect relatively milder disease burden or physician/patient reluctance to initiate/continue ERT at this age. Further studies are needed to increase knowledge of Fabry disease and ERT in later life.

Association of Periodontitis With Urinary Albumin Excretion in Korean Adults With Diabetes: The 2012 Korea National Health and Nutrition Examination Survey

Albuminuria and periodontitis are both commonly associated with systemic inflammation. However, the association between urinary albumin excretion (UAE) and periodontitis in patients with type 2 diabetes has not been fully investigated. This study aimed to investigate the association between UAE and periodontitis in Korean adults with type 2 diabetes.This study performed a cross-sectional analysis and used hierarchical multivariable logistic regression analysis models. Data from the 2012 Korean National Health and Nutrition Examination Survey were analyzed. A total of 547 patients, with type 2 diabetes without renal impairment, were included in this study. UAE was assessed using the urinary albumin to creatinine ratio (UACR). A community periodontal index greater than or equal to code 3 was used to define periodontitis.The risk of periodontitis tended to increase as UACR increased even after adjustment for potential confounders (P for trend in the odds ratios = 0.05 in model 1; 0.02 in model 2; and 0.01 in model 3). In a subgroup analysis, the prevalence of periodontitis was significantly higher in the patients with albuminuria (UACR >30 mg/g) than in those without albuminuria among patients younger than 65 years (P = 0.03), those with newly diagnosed diabetes (P = 0.04), or those without obesity (P = .04).UAE was positively associated with the risk of periodontitis in Korean adults with type 2 diabetes. In the patients who were younger, were newly diagnosed with diabetes, or had normal body mass index, individuals with albuminuria were more likely to have a higher prevalence of periodontitis. Early identification of periodontitis may be helpful in Korean diabetic adults with increased UAE.

Elevated brachial-ankle pulse wave velocity is independently associated with microalbuminuria in a rural population

Microalbuminuria is a marker of generalized endothelial dysfunction resulting from arterial stiffness or insulin resistance, and brachial-ankle pulse wave velocity (baPWV) is a good measure of arterial stiffness. We aimed to investigate whether elevated baPWV is independently associated with microalbuminuria. This study included 1,648 individuals aged over 40 who participated in the baseline Multi-Rural Cohort Study conducted in Korean rural communities between 2005 and 2006. Participants were classified into less than 30 mg/g as normoalbuminuria or 30-300 mg/g as microalbuminuriausing urinary albumin creatinine ratio (UACR). The median and Q1-Q3 baPWV values were significantly higher in the microalbuminuric group both in men (1,538, 1,370-1,777 cm/s vs. 1,776, 1,552-2,027 cm/s, P < 0.001) and women (1,461, 1,271-1,687 cm/s vs. 1,645, 1,473-1,915 cm/s, P < 0.001). BaPWV was independently associated with microalbuminuria in both genders after adjusting for pulse rate; fasting blood glucose; triglyceride; homeostatic model assessment insulin resistance (HOMAIR) and, history of hypertension and diabetes. Fasting blood sugar and HOMAIR were judged as having nothing to do with multicolinearity (r = 0.532, P < 0.001). Elevated baPWV was independently associated with microalbuminuria regardless of insulin resistance among rural subjects over 40 yr.

Abdominal obesity is associated with albuminuria in women: the 2011 Korea National Health and Nutrition Examination Survey

BACKGROUND

The effects of obesity on the kidney, apart from diabetes or hypertension, have not drawn much attention. Moreover, only a few studies have reported the relationship between obesity status and albuminuria in Asian countries, including South Korea. Therefore, this study aimed to investigate the association between obesity status and albuminuria in Korean adults.

METHODS

We analyzed data from the 2011 Korea National Health and Nutrition Examination Survey. Of the 4,979 subjects included in the general-population group, 3,274 were sorted into a nondiabetic and nonhypertensive population group. Obesity status was measured by body mass index and waist circumference. Albuminuria was defined as a urine albumin-to-creatinine ratio ≥30 mg/g.

RESULTS

Abdominally obese women were at higher risk for albuminuria than were women without abdominal obesity both in the general population (odds ratio [OR], 95% confidence interval [CI]: 2.08 [1.04-4.16]) and in the nondiabetic and nonhypertensive population (OR [95% CI]: 6.96 [2.34-20.64]) after further adjustment for confounders. Among generally nonobese women, abdominally obese women were at higher risk for albuminuria than were women without abdominal obesity both in the general population (OR [95% CI]: 2.82 [1.51-5.29]) and in the nondiabetic and nonhypertensive population (OR [95% CI]: 5.32 [1.47-19.22]).

CONCLUSION

Abdominal obesity is associated with an increased risk for albuminuria in Korean women, independently of diabetes or hypertension. Screening for abdominal obesity, especially in women, may therefore provide earlier identification of individuals at risk for developing renal disease and cardiovascular disease, even those who are nondiabetic and nonhypertensive.

Clinical Implications of the Change in Glomerular Filtration Rate with Adrenergic Blockers in Patients with Morning Hypertension: The Japan Morning Surge-1 Study

Background. The aim of this study was to clarify the relationship between the change in estimated glomerular filtration rate (eGFR) and urinary albumin by antihypertensive treatment.Methods. We randomized 611 treated patients with morning hypertension into either an added treatment group, for whom doxazosin was added to the current medication, or a control group, who continued their current medications. We compared the change in eGFR and urinary albumin creatinine ratio (UACR) between the groups.Results. The extent of the reduction in eGFR was significantly greater in the added treatment group than in the control group (−3.83  versus −1.08 mL/min/1.73 m2,P=0.001). In multivariable analyses, the change in eGFR was positively associated with the change in UACR in the added treatment group (β=0.20,P=0.001), but not in the control group (β=−0.002,P=0.97). When the changes in eGFR were divided by each CKD stage, eGFR was significantly more decreased in stage 1 than in the other stages in the added treatment group (P<0.001), but no differences were seen in the control group (P=0.44).Conclusion. The reduction of eGFR could be seen only in the early stage of CKD, and this treatment appeared to have no negative effect on renal function.

Distribution pattern of urine albumin creatinine ratio and the prevalence of high-normal levels in untreated asymptomatic non-diabetic hypertensive patients

BACKGROUND

Even high-normal albuminuria is reportedly associated with cardiovascular events.

OBJECTIVE

We determined the urine albumin creatinine ratio (UACR) in spot urine samples and analyzed the UACR distribution and the prevalence of high-normal levels.

PATIENTS AND METHODS

The UACR was determined using immunoturbidimetry in 332 untreated asymptomatic non-diabetic Japanese patients with hypertension and in 69 control subjects. The microalbuminuria and macroalbuminuria levels were defined as a UCAR ≥30 and <300 µg/mg·creatinine and a UCAR ≥300 µg/mg·creatinine, respectively.

RESULTS

The distribution patterns showed a highly skewed distribution for the lower levels, and a common logarithmic transformation produced a close fit to a Gaussian distribution with median, 25th and 75th percentile values of 22.6, 13.5 and 48.2 µg/mg·creatinine, respectively. When a high-normal UACR was set at >20 to <30 µg/mg·creatinine, 19.9% (66/332) of the hypertensive patients exhibited a high-normal UACR. Microalbuminuria and macroalbuminuria were observed in 36.1% (120/336) and 2.1% (7/332) of the patients, respectively. UACR was significantly correlated with the systolic and diastolic blood pressures and the pulse pressure. A stepwise multivariate analysis revealed that these pressures as well as age were independent factors that increased UACR.

CONCLUSION

The UACR distribution exhibited a highly skewed pattern, with approximately 60% of untreated, non-diabetic hypertensive patients exhibiting a high-normal or larger UACR. Both hypertension and age are independent risk factors that increase the UACR. The present study indicated that a considerable percentage of patients require anti-hypertensive drugs with antiproteinuric effects at the start of treatment.

Factors associated with impaired urinary albumin excretion in hypertensive individuals: albuminuria and hypertension

Albuminuria is well established as a cardiovascular and renal risk factor. This study aimed to analyze factors associated with this condition in 267 hypertensive individuals, stratified according to urinary albumin excretion (UAE) as: G1--130 individuals with normoalbuminuria (24-h UAE<20 μg/min); G2--113 with microalbuminuria (UAE between 20 and 200 μg/min); and G3--24 with macroalbuminuria (UAE≥200 μg/min). There were significant differences among the groups for blood pressure levels, left ventricular mass and index, estimated glomerular filtration rate, serum creatinine, renal dysfunction and diabetes mellitus (p<0.05). Macroalbuminuria was associated with renal dysfunction (OR=5.91; 95% CI: 2.44-14.31; p<0.001) and microalbuminuria with LVH (OR=2.21; 95% CI: 1.27-3.85; p=0.005). The association between UAE with blood pressure levels, diabetes and target-organ damage in hypertensive individuals suggests that adequate control of cardiovascular risk factors should be pursued to decrease morbidity associated with these conditions.

Urinary albumin excretion among nondipper hypertensive patients is closely related with the pattern of nondipping

The relationship between 24-hour urinary albumin excretion (UAE) rate and the pattern of nondipping (isolated systolic nondipping, isolated diastolic nondipping, and both systolic and diastolic nondipping) is not known. Medical history, physical examination, laboratory analysis, and office and ambulatory blood pressure measurements were performed. Twenty-four hour urine specimens were collected to determine creatinine clearance and UAE. In total, 158 essential hypertensive patients (104 dippers, 54 nondippers) were included. Fourteen patients were isolated systolic nondippers, 7 patients were isolated diastolic nondippers, and 33 patients were both systolic and diastolic nondippers. Among nondipper patients, 17 had microalbuminuria and, among dipper patients, 9 had microalbuminuria (P<.0001). The median UAE of dippers was lower when compared with nondippers (5.25 mg/day vs.23 mg/day, P<.0001). The median UAE of isolated systolic nondippers, isolated diastolic nondippers, and both systolic and diastolic nondippers were 8.45 mg/day, 7.7 mg/day, and 25.5 mg/day, respectively (P=.001). Subgroup comparison of patients revealed that UAE was higher in patients with both systolic and diastolic nondippers when compared with dippers (P<.0001), isolated systolic nondippers (P=.001), and isolated diastolic nondippers (P=.017). Not only nondipping itself, but nondipping profile may be related with UAE in essential hypertensive patients.

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.

Valsartan Reduces Serum Cystatin C and the Renal Vascular Resistance in Patients with Essential Hypertension

A high level of albuminuria and increased renal vascular resistance are associated with hypertensive renal damage. In this study, the authors investigated the effect of the angiotensin II receptor blocker, valsartan, on renal function and intrarenal hemodynamics in non-diabetic patients with essential hypertension. A prospective three-month study of the effects of valsartan, 40-80 mg/day, was performed in 30 hypertensive patients. As an assessment of renal function, serum creatinine, urine albumin/creatinine (Alb/Cr) ratio, and serum cystatin C levels were evaluated. Doppler ultrasonography of the kidney was performed for the evaluation of renal hemodynamics. Peak-systolic, end-diastolic, and mean velocities of interlobar arteries were evaluated, and the pulsatility index (PI) and resistive index (RI) were calculated. It was determined that patients with microalbuminuria had higher levels of serum cystatin C, PI, and RI compared to patients without microalbuminuria. Valsartan treatment significantly reduced systolic and diastolic blood pressure and decreased the Alb/Cr ratio. Serum creatinine was not changed, whereas serum cystatin C levels were significantly reduced. Valsartan treatment significantly decreased the PI in all patients and both PI and RI in patients with microalbuminuria. These results suggest that the angiotensin II receptor blocker, valsartan, is able to improve renal function by reducing renal vascular resistance in hypertensive patients, especially in patients with microalbuminuria, and may prevent future renal failure in patients with essential hypertension.

Relation of plasma midregional proatrial natriuretic peptide to target organ damage in adults with systemic hypertension

We tested the hypothesis that, in adults with essential hypertension, plasma levels of midregional proatrial natriuretic peptide (MR-proANP) are associated with target organ damage. MR-proANP is a newly described stable fragment of N-terminal proatrial natriuretic peptide. Participants included 1,919 adults with hypertension identified from the community (1,037 African-Americans, 65 +/- 9 years of age, 72% women; 882 non-Hispanic whites, 61 +/- 9 years of age, 55% women). We measured MR-proANP by an immunoluminometric assay. Measurements of target organ damage included the ankle-brachial index (ABI), urinary albumin-creatinine ratio (UACR), and left ventricular (LV) mass (available only in African-Americans). Generalized estimating equations were used to assess whether plasma MR-proANP was associated with measurements of target organ damage, independent of potential confounding variables. In African-Americans, higher MR-proANP was significantly associated with lower ABI (p <0.0001), higher UACR (p <0.0001), and greater LV mass (indexed to height to the power of 2.7, p <0.0001). After adjustment for age, gender, body mass index, systolic blood pressure, estimated glomerular filtration rate, smoking history, diabetes mellitus, total and high-density lipoprotein cholesterols, medication (blood pressure lowering, statin, and aspirin) use, and previous myocardial infarction or stroke, higher MR-proANP levels remained significantly associated with lower ABI (p = 0.01), higher UACR (p = 0.0007), and greater LV mass index (p <0.0001). In non-Hispanic whites, higher MR-proANP levels were significantly associated with lower ABI (p = 0.002) and greater UACR (p = 0.001), but not after adjustment for the covariates listed earlier. In conclusion, plasma MR-proANP may be a marker of target organ damage in the setting of hypertension, especially in African-Americans.

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.

Association of plasma resistin with glomerular filtration rate and albuminuria in hypertensive adults

Resistin, a recently discovered proinflammatory cytokine, has been variably associated with insulin resistance, inflammation, and renal dysfunction. We investigated the association of plasma resistin with estimated glomerular filtration rate and albuminuria in 1575 hypertensive adults without known coronary heart disease or stroke (857 blacks and 718 non-Hispanic whites). Resistin was measured by a solid phase sandwich immunoassay, estimated glomerular filtration rate was estimated from serum creatinine, and albuminuria was expressed as urine albumin:creatinine ratio. After adjustment for coronary heart disease risk factors (age, sex, body mass index, smoking history, systolic blood pressure, diabetes, and total and high-density lipoprotein cholesterol) and use of renin-angiotensin blockers and statins, higher plasma resistin levels were associated with lower estimated glomerular filtration rate in both ethnic groups (each P<0.0001); the association remained significant after further adjustment for a marker of insulin resistance (homeostasis model assessment for insulin resistance) and a marker of inflammation (plasma C-reactive protein) and was seen in subjects with and without diabetes (each P<0.0001) in both ethnic groups. Higher plasma resistin levels were associated with a higher urine albumin:creatinine ratio in black subjects with diabetes (P<0.0001) and non-Hispanic white subjects with diabetes (P=0.032), independent of coronary heart disease risk factors, hypertension medication use, and statin use; the association remained significant after additional adjustment for homeostasis model assessment for insulin resistance and C-reactive protein. In adults with hypertension, higher circulating resistin levels were associated with a lower estimated glomerular filtration rate and with increased urine albumin:creatinine ratio in the presence of concomitant diabetes. This association was independent of coronary heart disease risk factors and markers of insulin resistance and inflammation.

Intensive cardiovascular examination regarding blood pressure levels: evaluation of risk groups. ICEBERG study

OBJECTIVE

Assessment of total cardiovascular risk level is crucial for approaching hypertensive patients. Therefore, the aim of the Intensive/Initial Cardiovascular Examination regarding Blood pressure levels: Evaluation of Risk Groups (ICEBERG) study is to determine cardiovascular risk evaluation and stratification of subjects with high normal and high blood pressure (BP > or = 130/85 mmHg), and to evaluate the impact of laboratory tests on this stratification.

METHODS

ICEBERG was an epidemiological study conducted at 20 university hospitals and 197 primary healthcare centers. A total of 10,313 patients, who were diagnosed with high BP and under antihypertensive treatment or not antihypertensive under treatment at least for the last 3 months were selected. Besides routine clinical evaluation, microalbuminuria (MAU) and high sensitive C-reactive protein (hs-CRP) tests, echocardiography (Echo) and carotid ultrasonography (USG) were performed in selected arms. The patients were stratified into low, moderate, high and very high added risk groups as described by the European Society of Hypertension/European Society of Cardiology Guidelines Committee (2003).

RESULTS

Upon routine evaluation, the percentage of "high and very high added cardiovascular risk" groups was between 51.2% and 60.7% in different study arms. This percentage increased to 62.9% by subsequent serum biochemistry assessment and to 76.2% by hs-CRP test results. Switching upwards to "high and very high added risk" groups was around 6% when MAU results were used, with a 4.9% upwards switch to "high and very high added risk" groups when Echo was performed; this proportion increased by 6.8%, when carotid USG was taken into account.

CONCLUSION

Cardiovascular risk evaluation by intensive cardiovascular examination including Echo and carotid USG provided more accurate risk stratification. Furthermore, a simple test to demonstrate presence of MAU usable at primary healthcare level will also help to evaluate the patient's risk profile better than routine assessment methods alone.

Urinary albumin excretion is associated with impaired flow- and nitroglycerin-mediated brachial artery dilatation in hypertensive adults

We investigated whether the urinary albumin/creatinine ratio (UACR), a measure of albuminuria, is associated with non-invasive measures of arterial function in hypertensive adults without known coronary heart disease (CHD) or stroke. UACR was measured in the first voided morning urine sample in 469 non-Hispanic white hypertensive individuals (mean age 62.2+/-9.8 years, 41% men) belonging to hypertensive sibships. High-resolution ultrasonography of the brachial artery was used to assess flow-mediated dilatation (FMD)--an endothelium-dependent response--and nitroglycerin-mediated dilatation (NMD)--an endothelium-independent response. Because of skewed distribution, UACR was log transformed after addition of 0.1. The association of log (UACR+0.1) with FMD and NMD, before and after adjustment for CHD risk factors, serum creatinine, and hypertension medication and statin use was assessed using linear regression analyses. In univariable analyses, variables associated with lower FMD were greater age, male sex, history of smoking, lower high-density lipoprotein (HDL) cholesterol, higher serum creatinine and higher log (UACR+0.1); variables associated with lower NMD were greater age, male sex, higher systolic blood pressure, lower HDL cholesterol, higher serum creatinine and higher log (UACR+0.1). In separate stepwise multivariable regression analyses that adjusted for conventional CHD risk factors, serum creatinine and hypertension medication and statin use, higher log (UACR+0.1) was associated with lower brachial artery FMD (P=0.035) and NMD (P=0.0002). These findings highlight the association of increased urinary albumin excretion with impaired vascular reactivity in hypertensive individuals.

Urinary albumin excretion and the renin-angiotensin system in cardiovascular risk management

Microalbuminuria has been shown to be a strong predictor of cardiovascular morbidity and mortality in diabetic and hypertensive patients, but also in the general population. Moreover, several reports suggest that reduction of urinary albumin excretion (UAE) is associated with improvement of cardiovascular prognosis. Reduction of UAE can be achieved by lowering arterial blood pressure, but blockers of the renin-angiotensin system (RAS) with their specific renal actions have demonstrated to be able to reduce UAE more than might be expected from reduction of blood pressure alone. Consequently, angiotensin-converting enzyme inhibitors and angiotensin receptor blockers may also provide superior cardiovascular protection, especially in subjects with higher levels of albuminuria, but evidence is still scarce. The ability of both angiotensin-converting enzyme inhibitors and angiotensin receptor blockers to reduce UAE and provide cardiovascular protection suggests that the RAS may play a central role. New developments in this area include the use of aldosterone antagonists in albuminuric/proteinuric subjects, and the development of oral renin inhibitors. Combinations of the aforementioned drugs may have the ability to fully block the RAS, potentially avoiding all detrimental effects of this hormonal cascade. However, combination therapy is expected to also increase the incidence of side effects, such as hyperkalaemia and acute renal insufficiency. The current knowledge of microalbuminuria represents the proverbial tip of the iceberg, and future studies should focus on the underlying pathophysiological mechanism of urinary albumin excretion in relation to cardiovascular protection. Only then can a better understanding of the problem be achieved and the optimal pharmacological approach be ascertained.

Abdominal obesity, systolic blood pressure, and microalbuminuria in normotensive and euglycemic Korean men

OBJECTIVES

To evaluate the relationship between abdominal obesity and microalbuminuria (MA) in normotensive, euglycemic Korean men.

DESIGN

A cross-sectional study at a health screening center.

SUBJECTS

A total of 1321 healthy, normotensive Korean men, aged 20-78 years, with a fasting plasma glucose level <100 mg/dl.

MEASUREMENTS

Height, weight, and waist; systolic blood pressure (SBP); diastolic blood pressures (DBP); urinary albumin to creatinine ratio (ACR); fasting glucose, insulin, lipids, C-reactive protein (CRP), and white blood cell count. Waist circumference (WC) was used to indicate abdominal obesity and a single measurement of ACR was used to estimate MA. We also calculated body mass index (BMI) based on weight and height.

RESULTS

Mean BMI, WC, and SBP were significantly higher in subjects with MA than in those without (24.8+/-4.1 vs 23.8+/-2.7 kg/m2, 86+/-9 vs 83+/-8 cm, and 115+/-5 vs 112+/-7 mmHg, respectively). Multiple logistic regression analyses showed that only WC and SBP were independent predictors of MA.

CONCLUSION

WC and SBP were positively associated with MA in normotensive and euglycemic Korean men.

Microalbuminuria en pacientes diabéticos y en pacientes con hipertensión arterial: estudio de una cohorte de 979 pacientes

BACKGROUND AND OBJECTIVE

Microalbuminuria is a known complication of diabetes mellitus but it is also a cardiovascular risk factor commonly present among hypertensive (non diabetic) population. The prevalence of microalbuminuria is variable and it has been never estimated in our region. The aim of this study has been to determine the prevalence of microalbuminuria in hypertensive (non diabetic) and diabetic population in Extremadura (Spain).

PATIENTS AND METHOD

The study included diabetic patients and non-diabetic hypertensive ones randomly selected. Microalbuminuria was measured in every patient using albumin/creatinin reactive stick in fasting first morning urine. Whenever possible microalbuminuria was confirmed in laboratory by microalbuminuria/creatinina coefficient in first morning urine samples.

RESULTS

A total of 979 patients (mean age [SD], 67.9 [10.8] years; 409 men and 570 women, 505 diabetics) were studied. The presence of microalbuminuria was found in 12.4% of hypertensive patients and in 21.4% of diabetic patients (p < 0.001). Hypertensives and normotensive diabetics showed a similar prevalence of microalbuminuria (13.3%, not significant), but it tripled in hypertensive diabetics (33.8; p < 0.01). Glicemic control was not different for microalbuminuric diabetic patients and non microalbuminuric ones. The patients receiving rennin-angiotensin axis blocking drugs do not showed less prevalence of microalbuminuria (hypertensives 10.5%, diabetics 23.5%). Microalbuminuria was confirmed in 65.4% of patients.

CONCLUSIONS

The prevalence of microalbuminuria in Extremadura seems to be high either in diabetics or non diabetic hypertensive patients. The finding of microalbuminuria in diabetics patients correlates with hypertension but do not with glicemic control. The prevalence of microalbuminuria is high in spite of using rennin-angiotensin axis blocking drugs.

Renal Function in Patients with Abdominal Aortic Aneurysm

AIMS

Renal dysfunction occurs occasionally after the repair of abdominal aortic aneurysm (AAA), and preoperative renal function is considered as one of the potential causes. The present study was designed to evaluate and compare renal function and risk factors of AAA patients with those of hypertensive patients.

METHODS

We prospectively examined 95 patients with AAA and 72 patients with essential hypertension (HT) without other cardiovascular diseases (CVD). Renal function, urinary albumin excretion (UAE) and renal scintigraphy were compared. Kidney size was calculated using ultrasonography.

RESULTS

Serum creatinine and creatinine clearance in AAA patients was worse than in HT patients. Smoking status was more apparent in AAA patients. Renal artery stenosis occurred in 8 patients with AAA. Renal scintigraphy showed normal function in 19%, hypofunction in 69% and severe dysfunction in 12% of the AAA patients, and normal function in 42% and hypofunction in 58% of the HT patients (p < 0.0001). Multivariate linear regression analysis showed that renal function was related to age, UAE, CVD, smoking status and kidney size for all patients, UAE, CVD, smoking status and kidney size for AAA patients, and age and kidney size for HT patients.

CONCLUSION

Renal function of AAA patients was worse than HT patients without other CVD. The risk factors for renal dysfunction were different between AAA and HT patients. These preoperative conditions may relate to the postoperative renal dysfunction seen in AAA patients.

Brachial-Ankle Pulse Wave Velocity Is an Independent Risk Factor for Microalbuminuria in Patients with Essential Hypertension-A Japanese Trial on the Prognostic Implication of Pulse Wave Velocity (J-TOPP)

Brachial-ankle pulse wave velocity is a new measure of arterial stiffness. The clinical significance of brachial-ankle pulse wave velocity as a measure of early vascular damage remains unclear. We examined the hypothesis that higher brachial-ankle pulse wave velocity is associated with a much greater risk of albuminuria by employing a cohort of 718 never-treated hypertensive patients registered in a prospective study. The 718 patients consisted of 500 patients with normoalbuminuria (69.6%), 191 patients with microalbuminuria (26.6%) and 27 patients with macroalbuminuria (3.8%). The prevalence of microalbuminuria increased with a graded increase in brachial-ankle pulse wave velocity (17.6, 22.8, 28.2 and 39.6%, p < 0.0001). The prevalence of macroalbuminuria remained constant until the third grade group of the brachial-ankle pulse wave velocity but increased significantly in the highest grade group compared with the lower grade groups (2.3, 3.2, 2.3, 9.9%, p < 0.0001). Age, systolic and diastolic blood pressure, pulse pressure, heart rate, and fasting glucose concentration were also significantly increased with an increase in brachial-ankle pulse wave velocity (p < 0.0001 for all). Multiple logistic regression analysis has shown that systolic blood-pressure, fasting blood glucose, and brachial-ankle pulse wave velocity are significant risk factors for microalbuminuria. After adjusting for other risk factors, the odds ratio for an increase of 200 cm/s in brachial-ankle pulse wave velocity was 1.192 (95% confidence interval: 1.022-1.365; p < 0.05). These data suggest that brachial-ankle pulse wave velocity is an independent risk factor for microalbuminuria and could be used as a marker for early vascular damage in never-treated hypertensive patients.

Factors Related to Microalbuminuria in Nondiabetic Elderly Males with Normal Renal Function

Two hundred and three adult males were evaluated for the presence of microalbuminuria. Out of 203 patients, 123 (61%) tested negative for microalbuminuria and 80 (39%) tested positive. Patients were further evaluated for age, body mass index, cigarette smoking, blood pressure, serum lipid levels, renal function, cardiovascular events, and use of antihypertensive and antihyperlipidemic medications. This study shows that age greater than 70 years, creatinine clearance less than 50 mL/min, and systolic blood pressure greater than or equal to 140 mm Hg are all significant risk factors for microalbuminuria.

Minor abnormalities of renal function: a situation requiring integrated management of cardiovascular risk

Changes in renal function related with essential hypertension are associated with an elevated cardiovascular morbidity and mortality. Indices of altered renal function (e.g. microalbuminuria, increased serum creatinine concentrations, decrease in estimated creatinine clearance or overt proteinuria) are independent predictors of cardiovascular morbidity and mortality. The Framingham Heart Study documented the relevance of proteinuria for cardiovascular prognosis in the community. The Intervention as a Goal in Hypertension Treatment (INSIGHT) Study assessed the role of proteinuria as a very powerful risk factor. It has also been shown that microalbuminuria along with primary hypertension poses a high risk for cardiovascular diseases. Recent data indicate that even minor derangements of renal function are associated with the clustering of cardiovascular risk factors observed in metabolic syndrome, that promote progression of atherosclerosis. All these parameters should be routinely evaluated in clinical practice, and considered in any stratification of cardiovascular risk in hypertensive patients. The high prevalence of chronic kidney disease in the general and in the hypertensive populations implies the need for an integrative therapeutic approach to fully protect renal and cardiovascular systems simultaneously.

Transforming growth factor beta1 and additional renoprotective effect of combination ACE inhibitor and angiotensin II receptor blocker in hypertensive subjects with minor renal abnormalities: a 24-week randomized controlled trial

OBJECTIVE

To verify the benefit of renin-angiotensin system blockade in hypertension, the effects of 24 weeks' losartan and ramipril treatment, both alone and in combination, on urinary albumin excretion (UAE) and circulating transforming growth factor beta1 (TGF beta1) have been evaluated in hypertensive subjects with minor renal abnormalities.

DESIGN AND METHODS

Fifty-one patients with stage 1 and 2 essential hypertension and with UAE > or = 20 mg/24 h but with maintained renal function have been included. After a 4-week run-in with placebo administration, a randomized double-blind, three-arm double-dummy trial was used. All the hypertensives (HT) were allocated randomly to three treatment arms (17 patients for each group) and they were single-matched for age, gender, body mass index (BMI), systolic and diastolic blood pressure. Active treatment consisted of losartan (50 mg/day), ramipril (5 mg/day) and combined (losartan 50 mg/day plus ramipril 5 mg/day) for 24 weeks. Hydrochlorothiazide 12.5 mg/day was added in HT patients with uncontrolled blood pressure (> or = 140/90 mmHg) during the active treatment period. In all patients UAE, by immunonephelometric assay; circulating TGF beta1 by a solid-phase specific sandwich enzyme-linked immunosorbent assay (ELISA); and blood urea nitrogen (BUN), creatinine and creatinine clearance and potassium, by routine laboratory methods, were determined after placebo treatment and 24 weeks follow-up.

RESULTS

The three treatment groups were comparable for gender, age, BMI, blood pressure, UAE and renal function measurements. During the active treatment period it was necessary to add hydrochlorothiazide in five patients--two each of the losartan and ramipril groups and one of the combined group. At the end of treatment, significant (P < 0.05) reductions in systolic, diastolic and mean blood pressure, UAE and TGF beta1 levels were observed in all the groups. No change in renal function measurements were observed. The absolute and percentage reduction in UAE and TGF beta1 were significantly higher in the combined group than in the losartan or ramipril groups. No significant changes in absolute and percentage reduction of systolic, diastolic and mean blood pressure were found. All treatment regimens were well tolerated with few and transient side-effects.

CONCLUSION

These data indicate an additional renoprotective effect of dual blockade of the renin-angiotensin system (RAS) in hypertensive patients with minor renal abnormalities. In addition, the contemporaneus and marked decrease in TGF beta1 and UAE levels in hypertensives treated with combined therapy might indicate the presence of a subset of subjects who may benefit from complete RAS blockade.

Microalbuminuria, renal function and development of sustained hypertension

OBJECTIVE

Microalbuminuria (MA) is a marker of adverse outcome in hypertension. The aim of this study was to investigate the association of MA with cardiovascular risk factors and glomerular hyperfiltration in the early stage of hypertension and to assess its predictive value for the development of sustained hypertension requiring antihypertensive treatment.

DESIGN AND PARTICIPANTS

We studied 1041 young stage 1 hypertensive subjects. Study variables were 24-h ambulatory blood pressure and heart rate, anthropometric measures, metabolic variables, creatinine clearance and lifestyle factors analyzed as a function of ascending urinary albumin measured from 24-h collections. Subjects were followed until they developed sustained hypertension and were eligible for antihypertensive medication according to current guidelines.

SETTING

Seventeen outpatient clinics in Italy.

RESULTS

Eighty-five percent of the subjects were normoalbuminuric, 9% had borderline MA, and 6% had overt MA. No between-group differences were found for age, body mass index, heart rate, lifestyle factors and biochemistry in both genders. Creatinine clearance was greater in the subjects with overt MA and borderline MA than in the normoalbuminuric subjects (P = 0.003 and 0.011, respectively). In a two-way ANCOVA, microalbuminuric subjects both with hyperfiltration (P < 0.001) and with normal filtration (P = 0.04) had higher 24-h systolic blood pressure than subjects with normoalbuminuria and normal filtration. In a Cox analysis, neither MA nor hyperfiltration were significant predictors of development of sustained hypertension.

CONCLUSION

MA is not associated with an adverse metabolic risk profile in the early stage of hypertension. MA is associated with greater hemodynamic load and with glomerular hyperfiltration in this clinical setting, but does not help in predicting those subjects destined to develop sustained hypertension requiring antihypertensive therapy.

Effect of proteinuria and glomerular filtration rate on cardiovascular risk in essential hypertension

Changes in renal function related with essential hypertension are associated with an elevated cardiovascular morbidity and mortality. Indices of altered renal function (e.g., microalbuminuria, increased serum creatinine concentrations, decrease in estimated creatinine clearance or GFR, and overt proteinuria) are independent predictors of cardiovascular morbidity and mortality. The Framingham Heart Study documented the relevance of proteinuria for cardiovascular prognosis in the community. The INSIGHT Study assessed the role of proteinuria as a risk factor in essential hypertension. The presence of proteinuria at baseline turned out to be a very potent predictor for the development of cardiovascular events and death in patients with essential hypertension and one or more associated cardiovascular risk factors. Recent data indicate that minor derangements of renal function, including proteinuria, are associated, both in the community and in the hypertensive population, with the clustering of cardiovascular risk factors observed in metabolic syndrome that promote progression of atherosclerosis. Renal function has to be routinely evaluated in every hypertensive patient, and the presence of minor alterations considered in the stratification of cardiovascular risk in hypertensive patients.

Serum cystatin C level is a marker of end-organ damage in patients with essential hypertension

High urinary albumin excretion rate (AER) has been associated with the presence of atherosclerotic vascular damages and is an independent risk factor for all causes of death and cardiovascular morbidity and mortality in essential hypertensive patients. Serum cystatin C (s-CC) is a recently identified nonglycosylated 13-kD basic protein that has been suggested to be a useful marker of glomerular filtration rate. In the present study, we investigated the relationship between s-CC level and end-organ damages in the kidney, heart, and vessels of patients with essential hypertension. Sixty patients with essential hypertension participated in the present study. Patients with renal failure were excluded. Serum-CC level was measured by a particle-enhanced turbidimetric assay. Left ventricular mass index (LVMI) and intima media thickness (IMT) in the common carotid arteries were evaluated by ultrasound images. Twenty-four-hour blood pressure was measured by a cuff-oscillometric method. Serum-CC level was negatively correlated with creatinine clearance (r=-0.617, p<0.0001). It was also correlated with mean 24-h systolic blood pressure (24h-SBP) (r=0.308, p= 0.0167), LVMI (r=0.528, p<0.0001), and IMT (r=0.539, p<0.0001). Both AER and s-CC level were independently associated with mean 24h-SBP. AER but not s-CC level was associated with HDL-cholesterol. The present study was the first to demonstrate that s-CC level is a useful and convenient parameter of renal function, and may also prove to be an early marker of the severity of end-organ damage in patients with essential hypertension.

Hypertension and the vascular patient

Hypertension is intricately entwined in vascular pathology and morbidity and uncontrolled blood pressure is a leading cause of cardiovascular mortality. Unfortunately, many patients will present to the vascular surgeon with uncontrolled blood pressure elevation and yet, although vascular surgeons have been involved in treating the renovascular etiology, they seldom become actively involved in the medical management of hypertension. However, positive reinforcement by the vascular surgeon about the benefits of blood pressure control may significantly impact the patient's willingness to comply with medications. Some of these medications may also have secondary benefits such as reducing the incidence of diabetes. Accordingly modern vascular surgeons, who want to do more for their patients, need to have a basic understanding of hypertension and its treatment. This manuscript provides an overview of the modern definitions and treatment methods for primary hypertension that should provide the vascular surgeon with sufficient information to play an active role in the management of this co-morbid condition.

Microalbuminuria and arterial stiffness in a general population: the Shimanami Health Promoting Program (J-SHIPP) study

Microalbuminuria is an early marker of renal damage and has been shown to predict future cardiovascular mortality and morbidity in patients with diabetes or hypertension, as well as in subjects in the general population. In this study, we investigated the hypothesis that the presence of microalbuminuria reflects the advancement of arterial stiffness by using a study group of 136 community residents who had no cardiovascular diseases except for hypertension and who were not taking any medications. Urinary albumin concentration was determined by the standard method and corrected by creatinine. Microalbuminuria was defined as a urinary albumin/creatinine ratio of 2.0-30.0 mg/mmol creatinine. Arterial stiffness was evaluated by pulse wave velocity (PWV) determined at three points: from the heart to the carotid artery, to the brachial artery, and to the ankle. Carotid arterial pressure was determined using a tonometric sensor. Carotid ultrasonography was performed to measure carotid intima-media thickness (IMT) and carotid arterial internal dimension. Subjects with microalbuminuria had higher blood pressure and wider pulse pressure not only in the brachial artery but also in the carotid artery. Microalbuminuria was associated with significantly higher PWV compared with that of normoalbuminuric subjects at all sites studied (mean PWV: 821.2+/-137.4 cm/s vs. 933.8+/-137.5 cm/s, p<0.0001). Stepwise regression analysis revealed that the presence of mircroalbuminuria (p=0.047) was a significant independent predictor of PWV in addition to age, sex, and systolic blood pressure. These findings suggest that microalbuminuria is associated with advanced atherosclerosis in the general population. Underlying arterial stiffness may explain the high cardiovascular mortality in subjects with microalbuminuria. Hypertension may be the mechanism linking microalbuminuria and arterial stiffness in the general population.

Microalbuminuria and all-cause mortality in treated hypertensive individuals: does sex matter? The Nord-Trøndelag Health Study (HUNT), Norway

BACKGROUND

In hypertensive individuals, few prospective studies are available in which the association between microalbuminuria (MA) and all-cause mortality in the 2 sexes have been studied within the same population.

METHODS AND RESULTS

We conducted a 4.3-year follow-up of 2307 men and 3062 women (> or =20 years old) with self-reported treated hypertension, all identified in the Nord-Trøndelag Health Study (HUNT), Norway, 1995 to 1997 (n=65 258). The main outcome measures were relative risk (RR) of all-cause mortality according to increasing albuminuria, defined at different levels of albumin-to-creatinine ratio (ACR). There was a consistent positive association between increasing ACR and all-cause mortality in men. The adjusted RR for ACR in the fourth quartile (> or =1.70 mg/mmol) was 1.6 (95% CI, 1.0 to 2.6), compared with ACR in the first quartile (<0.55 mg/mmol). The corresponding RR in women was 1.5 (95% CI, 0.8 to 3.1). We found a positive association between mortality and increasing number of urine samples with ACR above different cutoff levels, especially in men. In 3 urine samples, the lowest ACR level associated with mortality in men was 0.86 mg/mmol, RR 1.6 (95% CI, 1.1 to 2.4). The sex differences persisted after exclusion of those who died during the first year of follow-up, those with hypertension not treated optimally, and those with known cardiovascular disease.

CONCLUSIONS

The association between ACR and all-cause mortality was stronger in treated hypertensive men than in women. The persistent sex differences indicate that hypertensive women tolerate MA better than men and that MA in women should be interpreted differently than in men.

Microalbuminuria in hypertension

A body of evidence indicates that microalbuminuria is a well-recognized marker of cardiovascular complications and increased cardiovascular risk in hypertension. However, the prognostic significance of microalbuminuria remains controversial because only the results of a few prospective studies performed in small groups of hypertensive subjects without diabetes mellitus are available. Several factors can affect the prevalence of microalbuminuria in hypertension including age, sex, race, severity of the disease, and concomitant risk factors. This accounts for the large differences in the prevalence of microalbuminuria that can be found in the literature, with prevalence rates going from a low of 4.7% to a high of 46%. The main determinant of albumin excretion rate in subjects with mild hypertension and no cardiovascular complications seems to be the hemodynamic load, whereas in subjects with more severe hypertension and associated target organ damage, the augmented urinary albumin leak is probably the consequence of glomerular damage. Inhibition of the renin-angiotensin system with angiotensin-converting enzyme inhibitors or angiotensin II receptor antagonists is particularly effective at reducing the albumin excretion rate, but whether these classes of drugs are more beneficial in patients with microalbuminuria remains to be determined. There is general consensus that evaluation of microalbuminuria is useful for the assessment of overall cardiovascular risk in hypertension, since albumin excretion rate appears to be a cost-effective way to identify patients at higher risk for whom additional preventive and therapeutic measures are advisable.

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.

Microalbuminuria, cardiovascular, and renal risk in primary hypertension

Microalbuminuria is defined as abnormal urinary excretion of albumin between 30 and 300 mg/d. It can be measured accurately by several widely available and sensitive methods. This abnormality can be found in 8 to 15% of nondiabetic patients with primary hypertension, although its prevalence varies greatly in the literature, likely due to differences in the methods used to detect it and to the criteria applied in the selection of patients. The pathogenetic mechanisms leading to the development of microalbuminuria are still not completely known. BP load and increased systemic vascular permeability, possibly due to early endothelial damage, seem to play a major role. Increased urinary albumin excretion has been associated with several unfavorable metabolic and nonmetabolic risk factors and subclinical hypertensive organ damage. In fact, a higher prevalence of concentric left ventricular hypertrophy and subclinical impairment of left ventricular performance, as well as the presence of carotid atherosclerosis, have been reported in patients with microalbuminuria. These associations might per se justify a greater incidence of cardiovascular events. Long-term longitudinal studies have recently confirmed the unfavorable prognostic significance of microalbuminuria in hypertensive patients. It has also been hypothesized that microalbuminuria might be a forerunner of overt renal damage in primary hypertension. Clinical studies, however, have shown conflicting results, and this hypothesis has to be considered tempting but speculative at present. In conclusion, microalbuminuria is a specific, integrated marker of cardiovascular risk and target organ damage in primary hypertension and one that is suitable for identifying patients at higher global risk. A wider use of this test in the diagnostic work-up of hypertensive patients is recommended.

A blood pressure independent association between glomerular albumin leakage and electrocardiographic left ventricular hypertrophy. The LIFE Study. Losartan Intervention For Endpoint reduction

In the Losartan Intervention For Endpoint reduction (LIFE) study left ventricular (LV) hypertrophy was associated with increased urine albumin/creatinine ratio (UACR) at baseline. To evaluate whether this association was due only to parallel blood pressure (BP)-induced changes we re-examined the patients after 1 year of antihypertensive treatment to investigate whether changes in LV hypertrophy and UACR were related independently of changes in BP. In 7,142 hypertensive patients included in the LIFE study, we measured UACR, LV hypertrophy by electrocardiography, plasma glucose and BP after 2 weeks of placebo treatment and again after 1 year of antihypertensive treatment with either an atenolol or a losartan based regime. At baseline and still after 1 year of treatment logUACR (R = 0.28, P < 0.001) was still correlated to LV hypertrophy (beta = 0.05) assessed by ECG independently of systolic BP (beta = 0.16), plasma glucose (beta = 0.19) and age (beta = 0.08). Change in logUACR (R = 0.19, P < 0.001) during treatment was correlated to change in LV hypertrophy (beta = 0.10) independently of reduction in systolic BP (beta = 0.13) and change in plasma glucose (beta = 0.06). After 1 year of antihypertensive treatment UACR was still related to LV hypertrophy independently of systolic BP, and the reduction in UACR during that first year of treatment was related to regression of LV hypertrophy independently of reduction in systolic BP. This suggests that the relationship between LV hypertrophy and glomerular albumin leakage is not just due to parallel BP-induced changes. As glomerular albumin leakage may represent generalised vascular damage we hypothesise a vascular relationship between cardiac and glomerular damage.

Urinary protein and essential hypertension in black and in white people

The objectives of this work were to examine the association between urinary protein and blood pressure and to compare the pattern of urinary protein excretion with essential hypertension in people of European origin (whites) and in people of African or African-Caribbean origin (blacks) living in southwest London, United Kingdom. In the groups as a whole, there were no significant differences in total urinary protein excretion between blacks and whites (geometric means [95% CI]: 94.0 [85.9 to 102.9] mg/24h for the blacks [n=151] and 102.1 [96.1 to 108.4] mg/24h for the whites [n= 219]). There were also no significant differences between blacks and whites in urinary albumin (6.5 [4.9 to 8.5] mg/24h for the blacks [n=97] and 7.1 [5.6 to 9.0] mg/24h for the whites [n=123]). In both groups, those with essential hypertension displayed a significantly raised urinary protein excretion (1.21-fold higher for the blacks and 1.19-fold higher for the whites) and albumin excretion (1.69-fold higher for the blacks and 2.40-fold higher for the whites). Urinary transferrin excretion measured in a subgroup of 67 subjects was also raised in those with essential hypertension (3.22-fold higher in the blacks and 2.76-fold higher in the whites). Examination of urinary proteins by SDS-PAGE did not identify any pattern consistent with a reduction in renal tubular protein reabsorption in those with essential hypertension. These results suggest that the increase in protein excretion in essential hypertension could be due, at least in part, to an increase in glomerular protein ultrafiltration.

Albuminuria in hypertension is linked to altered lysosomal activity and TGF-beta1 expression

Increased intraglomerular pressure is considered a major factor for increased albumin excretion in hypertension. However, other factors should also be considered because recent studies in both humans and rats have demonstrated that proteins undergoing filtration and renal passage are extensively modified by renal cell lysosomal processing; >95% of albumin is degraded to peptides that are not detected by routine immunochemical assays. Changes in postglomerular lysosomal processing may therefore be responsible for the increased intact albumin excreted in hypertension-related kidney disease. We hypothesize that transforming growth factor-beta, which is known to decrease lysosomal activity, may be upregulated in hypertension and may play a role in increased intact albumin excretion. The aims of this study were to determine the effect that hypertension has on (1) renal cell lysosomal processing of albumin and dextran sulfate, (2) glomerular permeability, and (3) renal transforming growth factor-beta(1) expression. Spontaneously hypertensive rats and Wistar-Kyoto rats were used at 8, 16, and 24 weeks. We demonstrate that albuminuria in hypertension is linked to an inhibition of lysosomal processing as determined by (1) size exclusion chromatography analysis of urinary [(14)C]albumin structural integrity and (2) ion exchange analysis of urinary [(3)H]dextran sulfate. This inhibition gives rise to an increased proportion of radioimmunoassay detectable (intact) albumin and intact dextran sulfate independent of changes in glomerular capillary wall permeability as determined by the fractional clearance of [(3)H]Ficolls of various radii. These changes may be correlated with increased renal transforming growth factor-beta(1) expression.