Microalbuminuria in essential hypertension

Effects of verapamil slow release plus trandolapril combination therapy on essential hypertension

BACKGROUND

Fixed-dose combination antihypertensive therapy has been recommended for patients with essential hypertension who are unresponsive to monotherapy or as a first-line treatment.

OBJECTIVE

We investigated the effects of a fixed-dose combination of the phenylalkylamine-type calcium channel blocker verapamil slow release (SR)plus the angiotensin-converting enzyme inhibitor trandolapril on blood pressure (BP), serum lipid profile, urinary albumin excretion (UAE), left ventricular mass (LVM), and LVM index (LVMI), as well as the adverse events associated with this treatment.

METHODS

Patients aged 30 to 65 years with mild to moderate essential hypertension were included in the study. All of the patients received capsules containing combination treatment with verapamil SR 180 mg plus trandolapril 2 mg orally, daily for 12 weeks. Mean arterial pressure (MAP), systolic BP (SBP), diastolic BP (DBP), and heart rate (HR) were measured at baseline and at 4, 8, and 12 weeks of treatment. Serum lipid profile, UAE, LVM, LVMI, and body mass index (BMI) were determined at baseline and at the end of the study period. All patients underwent electrocardiography and echocardiography at baseline and week 12. The primary end point of the study was to achieve an SBP/DBP ≤140/≤90 mm Hg (ie, normotensive) during week 12. All adverse events were assessed as mild, moderate, or severe at each visit. According to the response rate at week 12, patients were divided into 2 groups: those who became normotensive (responders) or those who remained hypertensive (SBP/DBP >140/>90 mm Hg; nonresponders).

RESULTS

Forty-one patients (29 women, 12 men; mean [SD] age, 47.7 [7.8] years; mean [SD] BMI, 29.4 [3.5] kg/m(2)) were enrolled. The median durationof hypertension prior to enrollment was 5 months. Mean MAP, SBP, DBP, UAE, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), LDL-C/highdensity lipoprotein cholesterol (HDL-C) ratio, LVM, LVMI, and BMI decreased significantly after 12 weeks of combination treatment; HR and triglyceride level did not change significantly. Treatment-related adverse events occurred in 31.7% of patients, and none were severe or caused any patient to withdraw from the study. The most common adverse events were cough, constipation, headache, and dryness in the throat. Microalbuminuria, which may be a marker of endothelial dysfunction, was found in 7 (17.1%) patients at baseline and regressed significantly after 12 weeks.

CONCLUSIONS

In this study population, the fixed-dose combination of verapamil-trandolapril was an effective and well-tolerated antihypertensive therapy. This combination significantly reduced MAP, BP, TC, LDL-C, LDL-C/HDL-C ratio, UAE, LVM, and LVMI. Also, microalbuminuria decreased after this treatment. Verapamil-trandolapril may be useful in preventing microalbuminuria and left ventricular hypertrophy in patients with essential hypertension.

Morning pulse pressure is associated more strongly with elevated albuminuria than systolic blood pressure in patients with type 2 diabetes mellitus: post hoc analysis of a cross-sectional multicenter study

AIMS

Recently, focus has been directed toward pulse pressure as a potentially independent risk factor for micro- and macrovascular disease. This study was designed to examine the relationship between pulse pressure taken at home and elevated albuminuria in patients with type 2 diabetes.

METHODS

This study is a post hoc analysis of a cross-sectional multicenter study. Home blood pressure measurements were performed for 14 consecutive days in 858 patients with type 2 diabetes. We investigated the relationship between systolic blood pressure or pulse pressure in the morning or in the evening and urinary albumin excretion using univariate and multivariate analyses. Furthermore, we measured area under the receiver-operating characteristic curve (AUC) to compare the ability to identify elevated albuminuria, defined as urinary albumin excretion equal to or more than 30 mg/g creatinine, of systolic blood pressure or pulse pressure.

RESULTS

Morning systolic blood pressure (β=0.339, P<0.001) and morning pulse pressure (β=0.378, P<0.001) were significantly associated with logarithm of urinary albumin excretion independent of other potential co-factors. AUC for elevated albuminuria in morning systolic blood pressure and morning pulse pressure were 0.668 (0.632-0.705; P<0.001) and 0.694 (0.659-0.730; P<0.001), respectively. AUC of morning pulse pressure was significantly greater than that of morning systolic blood pressure (P=0.040).

CONCLUSIONS

Our findings implicate that morning pulse pressure is associated with elevated albuminuria in patients with type 2 diabetes, which suggests that lowering morning pulse pressure could prevent the development and progression of diabetic nephropathy.

The relationship between microalbuminuria and the presence and extent of coronary atherosclerosis

OBJECTIVE

To evaluate the relationship between microalbuminuria (MA) and the presence and extent of coronary artery disease (CAD).

METHODS

Four hundred and two consecutive patients were divided into 4 groups based on the presence of diabetes mellitus (DM) and MA: DM(+)/MA(+), DM(+)/MA(-), DM(-)/MA(+), and DM(-)/MA(-). Severity of CAD was assessed by the Gensini scoring system.

RESULTS

The Gensini score was 57 +/- 38.2 vs 16.5 +/- 19.5 (P < .001) in the DM(+)/MA(+) and DM(+)/MA(-) groups and 45 +/- 39.8 vs 9.9 +/- 16.6 (P < .001) in the DM(-)/MA(+) and DM(-)/MA(-) groups. Spearman correlation analysis demonstrated a positive relation between urine albumin/creatinine ratio (ACR) and extent of CAD both in the diabetic and nondiabetic patients (r = .584, P = .001; r = .545, P = .001). Microalbuminuria was found to be an independent predictor for the presence (OR for MA: 3.728; 95% CI, 1.931-7.196; P < .001) and severity of CAD (P < .001, beta = .563).

CONCLUSION

A strong relationship between MA and the severity of CAD was reported.

Abdominal obesity is associated with microalbuminuria and an elevated cardiovascular risk profile in patients with hypertension

Background

Overweight and obesity are frequently associated with preventable death and have emerged as a major challenge to public health. There is an ongoing debate on the role of abdominal obesity and its value in predicting cardiovascular and renal outcomes. The present analysis evaluates the prevalence of microalbuminuria (MAU) and conventional cardiovascular risk factors in relation to measures of general and abdominal obesity.

Methods

In this multinational, observational study, 20828 hypertensive out-patients from 26 countries including Europe, North and Latin America, Middle East, and Asia were analyzed. Urinary dipstick screening for MAU was performed as well as data on patient demographics, anthropometric measures, cardiovascular risk factors, comorbid conditions, and cardiovascular drug therapy collected. MAU prevalence was determined by a stepwise logistic regression analysis with cardiovascular risk factors as univariate.

Results

In the univariate analysis, MAU prevalence systematically increased with body mass index (BMI) from 54.4% (1st tertial) to 62.1% (3rd tertial) (p < 0.0001), an increase which was also observed for waist circumference (WC). At any level of BMI, MAU increased with WC from 53.5%, 54.8%, and 55.0% (1st tertial of WC in all three BMI tertials) to 61.4%, 62.1%, and 64.0% (3rd tertial of WC in all BMI tertials) (p < 0.0001). In the multivariate analysis, WC, but not BMI was independently associated with MAU. Furthermore, overweight/obesity were associated with the presence of modifiable and nonmodifiable risk factors.

Conclusion

An abnormal WC, but not BMI appears to be independently associated with MAU, an early marker of cardiovascular and renal risk. Increasing WC confers an incremental risk for MAU at any level of BMI, underlining the prognostic importance of abdominal fat accumulation beyond general obesity.

Atrial fibrillation and heart rate independently correlate to microalbuminuria in hypertensive patients

AIMS

To investigate the relationship between microalbuminuria (MAU) and atrial fibrillation (AF) and to further evaluate whether the heart rate dependency of MAU in patients without AF is maintained in patients with a history of AF.

METHODS AND RESULTS

The International Survey Evaluating Microalbuminuria Routinely by Cardiologists in patients with Hypertension (I-SEARCH) included 18,900 patients without and 1705 patients with a history of AF suffering from hypertension and other risk factors for cardiovascular disease in 26 countries worldwide from September 2005 to March 2006. Heart rate, blood pressure, urinary albumin excretion, and an estimated glomerular filtration rate were determined among other parameters. The prevalence of MAU was higher at higher heart rate in both patients with and without a history of AF. Prevalence of MAU was about 10% higher in patients with a history of AF (P < 0.001). Male gender, the presence of diabetes mellitus, a higher heart rate, and a higher diastolic blood pressure were independently associated with increased odds for MAU in patients without and with a history of AF.

CONCLUSION

The prevalence of MAU in hypertensive patients with cardiovascular risk factors is related to heart rate and significantly higher in patients with a history of AF.

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.

Use of predictive markers to improve cardiovascular protection

Together with other modifiable cardiovascular risk factors, hypertension heavily contributes to the global burden of cardiovascular morbidity and mortality, as well as to the increase in individual absolute cardiovascular risk. Comparison of the effectiveness of different therapies in reducing the incidence of major cardiovascular events has classically required the evaluation of major 'hard' end points. In view of the long natural history of hypertension, however, it appears very useful to monitor modifications in measurable 'intermediate' end points or 'disease markers'. This approach may provide more accurate individual risk stratification and a better evaluation of the efficacy of a given treatment in preventing or modifying the course of target organ damage. This may represent a valuable and affordable strategy in clinical practice allowing the evaluation of both patient prognosis and the effectiveness of antihypertensive treatment over time.

Relationship between inflammatory markers, metabolic and anthropometric variables in the Caribbean type 2 diabetic patients with and without microvascular complications

BACKGROUND

Serum sialic acid and C reactive protein are the markers for inflammation. The main objective of this study was to determine the sialic acid level in Caribbean type 2 diabetic patients with and without microvascular complications and its relationship with metabolic and anthropometric variables.

RESEARCH DESIGN AND METHODS

The Caribbean subjects aged 15-60 years with type 2 diabetes were recruited for the study. Fasting venous blood samples were collected from 162 subjects of which 44 were healthy individuals, 44 were of type 2 diabetes, 44 were of type 2 diabetes with nephropathy and 30 were of diabetes with retinopathy. Simultaneously urine samples were also collected from each of the subjects. All the blood samples were processed for lipid profile, glucose, HbA1C, C-reactive protein and sialic acid. The urine samples were analysed for sialic acid and microalbumin.

RESULTS

Serum sialic acid concentrations were significantly higher among diabetic subjects (66.0 +/- 11.7 mg %) as compared to controls (55.2 +/- 8.3 mg %). There was a significantly increasing trend of serum sialic acid with severity of nephropathy (71.6 +/- 23.6 mg %) and degree of urinary albumin excretion (794.3 +/- 805.9). The diabetic retinopathy patients also demonstrated significantly higher values of serum sialic acid (77.9 +/- 29.0) and urine microalbumin (351.1 +/- 559.9). Elevated serum sialic acid microalbumin concentrations were associated with cardiovascular risk factors such as hypertension, increased waist to hip ratios. (P < 0.05). Sialic acid had no correlation with CRP or any component of the lipid profile.

CONCLUSION

The increased serum sialic acid and microalbumin were strongly related to the presence of microvascular complications like diabetic nephropathy and diabetic retinopathy and cardiovascular risk factors like hypertension and waist to hip ratios in Caribbean type-2 diabetic patients. The serum sialic acid may be used as an inflammatory marker and possible indicator of microvascular complications in type-2 diabetic patients.

Ambulatory pulse pressure and progression of urinary albumin excretion in older patients with type 2 diabetes mellitus

We studied whether ambulatory blood pressure monitoring added to office blood pressure in predicting progression of urine albumin excretion over 2 years of follow-up in a multiethnic cohort of older people with type-2 diabetes mellitus. Participants in the Informatics for Diabetes Education and Telemedicine study underwent a baseline evaluation that included office and 24-hour ambulatory blood pressure measurement and a spot urine measurement of albumin-to-creatinine ratio (ACR). Measurements of albumin-to-creatinine ratio were repeated 1 and 2 years later. In bivariate analyses, ambulatory 24-hour pulse pressure was the blood pressure variable most strongly associated with follow-up ACR. Repeated-measures mixed linear models (n = 1040) were built adjusting for baseline ACR ratio, clustered randomization, time to follow-up, and multiple covariates. When both were entered into the model, ambulatory 24-hour pulse pressure and office pulse pressure were independently associated with follow-up ACR (beta [SE] = 0.010 [0.002], P < 0.001, and 0.004 [0.001], P = 0.002, respectively). Cox proportional hazards models examined associations with progression of albuminuria in 954 participants without macroalbuminuria at baseline, adjusting for all of the covariates independently associated with follow-up ACR in mixed linear models. Ambulatory 24-hour pulse pressure, but not office pulse pressure, was independently associated with progression of albuminuria (P = 0.015 and 0.052, respectively). The adjusted hazards ratio (95% CI) per each 10-mm Hg increment in ambulatory pulse pressure was 1.23 (1.04 to 1.42). In conclusion, ambulatory pulse pressure may provide additional information to predict progression of albuminuria in elderly diabetic subjects above and beyond office blood pressure.

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.

24-h Ambulatory blood pressure in patients with ECG-determined left ventricular hypertrophy: left ventricular geometry and urinary albumin excretion—a LIFE substudy

This study was undertaken to evaluate the relationships among left ventricular (LV) geometric patterns and urinary albumin excretion in patients with hypertension and electrocardiographic (ECG) LV hypertrophy. In 143 patients with stage II-III hypertension, 24-h ambulatory blood pressure (BP) monitoring, single urine albumin determination, and echocardiography were performed after 14 days of placebo treatment. Mean age was 68+/-7 years, 35% were women, body mass index was 28+/-5 kg/m(2), LV mass index (LVMI) was 125+/-26 g/m(2), and 24% had microalbuminuria. The mean office BP was 176+/-15/99+/-8 mmHg and the mean daytime ambulatory BP was 161+/-18/92+/-12 mmHg. Ambulatory BP, but not office BP, was higher among albuminuric compared to normoalbuminuric patients. In patients with established hypertension, daytime pulse pressure and office BP were different in the four patterns of LV geometry, with the highest pressure in those with abnormal geometry. Furthermore, microalbuminuria was more frequent in hypertensive patients with LV hypertrophy than in those with either normal geometry or concentric remodelling. White coat hypertensives (10%) showed lower LVMI and no microalbuminuria compared to patients with established hypertension. There were no differences in the prevalence of nondippers (26%) among the four LV geometric patterns or in microalbuminuria. In conclusion, increased daytime pulse pressure and office BP were associated with increased prevalence of abnormal LV geometry. Microalbuminuria was more frequent in groups with concentric and eccentric LV hypertrophy. Ambulatory BP, but not office BP, was higher in albuminuric than normoalbuminuric patients. With regard to the relationship among BP, LV geometric patterns, and urine albumin excretion in this population, 24-h ambulatory BP did not provide additional information beyond the office BP.

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.

Patients with essential hypertension present higher levels of sE-selectin and sVCAM-1 than normotensive volunteers

In essential hypertension (EH) patients, blood pressure can modify serum concentrations of some soluble forms of cell adhesion molecules (CAM), e.g., soluble E-selectin (sE-selectin) and soluble vascular cell adhesion molecule-1 (sVCAM-1). The objective of this study was to compare the serum levels of these CAMs in compensated (CH) and non-compensated (NCH) EH patients. Our findings show that sE-selectin and sVCAM-1 levels are higher in EH patients than normotensive subjects (sVCAM-1: 796+/-52 vs. 605+/-24 ng/mL, p<0.0001, and sE-selectin: 71+/-21 vs. 48+/-14 ng/mL, p<0.0001). Serum concentrations of both CAMs was higher in NCH patients than CH patients. High arterial blood pressure (ABP) may therefore increase the production of cell adhesion molecules, probably through endothelial activation.

Heterogeneity of Cardiorenal Characteristics in Normotensive Subjects

Blood pressure is a marker of elevated risk for cardiovascular disease, even within the normotensive range. The present study evaluates cardiorenal modifications observed in normotensive (<140/90 mm Hg) subjects. Using World Health Organization–International Society of Hypertension definitions, 265 normotensive subjects were categorized as having optimal (n=73), normal (n=84), and high-normal (n=108) blood pressure. Renal hemodynamics and function and cardiac morphology were evaluated by isotopic clearance techniques and ultrasonography, respectively. Urinary albumin excretion was measured in 24-hour urine collections. Body mass index and 24-hour urinary sodium (estimate of sodium intake), as well as left ventricular mass index, relative wall thickness, and glomerular filtration rate and filtration fraction, progressively increased in the optimal to high-normal groups. In contrast, effective renal plasma flow remained constant. Albuminuria was similar in all groups. Of interest, the proportion of subjects with concentric pattern of cardiac geometry (relative wall thickness ≥0.44) increased from 7% in optimal to 13% and 20% in normal and high-normal groups, respectively ( P <0.05). Within this normotensive range of blood pressure, left ventricular mass index and relative wall thickness but not albuminuria were linearly correlated to systolic blood pressure; however, no correlation with diastolic blood pressure was found. In conclusion, changes in cardiac geometry and renal hemodynamics (increase in glomerular filtration rate and filtration fraction, an approximate index of glomerular pressure) that could predispose to cardiovascular morbidity and renal risk are already present in normotensive subjects with blood pressure higher than 120/80 mm Hg.

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.

Left ventricular remodeling and renal function in never-treated essential hypertension

In the general population, renal function linearly declines with age; hypertension may accelerate this decline. Because concentric left ventricular (LV) hypertrophy is a strong marker of the severity of hypertension, the influence of LV geometry on the age-associated decline in renal function was assessed in 195 normotensive subjects and 645 patients with never-treated essential hypertension with an average duration of 30 mo. According to LV mass and relative wall thickness, hypertensive patients were divided into normal LV (NL, 48%), concentric remodeling (CR, 19%), and concentric (CH, 22%) and eccentric (EH, 11%) hypertrophy. GFR and effective renal plasma flow (ERPF) were estimated by isotopic clearance technique. GFR and ERPF were inversely correlated with age in normotensive and hypertensive subjects, and no marked influence of the BP level or the presence of LV hypertrophy was detected. However, the slope of the regression line of GFR versus age was accentuated (P < 0.01) in patients with CH or CR (slope values of -0.95 +/- 0.11, -0.86 +/- 0.14 ml/min per yr, respectively) when compared with patients with EH or NL (slope values of -0.58 +/- 0.16 and -0.58 +/- 0.08 ml/min per yr, respectively). No such results were obtained when creatinine clearance was considered. Urinary albumin excretion was higher in patients with concentric or eccentric LV hypertrophy than in patients with concentric LV remodeling or normal LV. These results demonstrate that in never-treated essential hypertension, the age-associated decline in GFR is markedly influenced by the concentric pattern of LV response to hypertension rather than the level of BP and/or the presence of LV hypertrophy.

Cigarette smoking: an important renal risk factor - far beyond carcinogenesis

In recent years, it has become apparent that smoking has a negative impact on renal function, being one of the most important remediable renal risk factors. It has been clearly shown that the risk for high-normal urinary albumin excretion and microalbuminuria is increased in smoking compared to non-smoking subjects of the general population. Data from the Multiple Risk Factor Intervention Trial (MRFIT) indicate that at least in males, smoking increases the risk to reach end-stage renal failure. Smoking is particularly "nephrotoxic" in older subjects, subjects with essential hypertension and patients with preexisting renal disease. Of interest, the magnitude of the adverse renal effect of smoking seems to be independent of the underlying renal disease. Death-censored renal graft survival is decreased in smokers, indicating that smoking also damages the renal transplant. Cessation of smoking has been show to reduce the rate of progression of renal failure both in patients with renal disease or a renal transplant. The mechanisms of smoking-induced renal damage are only partly understood and comprise acute hemodynamic (e.g., increase in blood pressure and presumably intraglomerular pressure) and chronic effects (e.g., endothelial cell dysfunction). Renal failure per se leads to an increased cardiovascular risk. The latter is further aggravated by smoking. Particularly survival of smokers with diabetes mellitus on hemodialysis is abysmal. In the present review article the current state of knowledge about the renal risks of smoking is reviewed. It is the aim of the article to point out that smoking not only increases the risk of renal cell carcinoma or uroepithelial cell carcinoma, but also the risk of a faster decline of renal function. The latter is a relatively new negative aspect which has not been widely recognized.

Angiotensin-II receptor antagonist losartan reduces microalbuminuria in hypertensive renal transplant recipients

In recent years, it has been demonstrated that losartan lowers macroproteinuria in diabetic or non-diabetic renal transplant recipients (RTx) similar to angiotensin converting enzyme (ACE) inhibitors. Microalbuminuria (MAU) may reflect subclinical hyperfiltration damage of the glomerulus. It could be a marker of kidney dysfunction in renal transplantation. The aim of the study was to assess the efficacy of losartan in hypertensive RTx with MAU. This study was conducted in 17 (M/F: 4/13) stable RTx. No change was made in the medical treatment of the patients. All cases received 50 mg/day losartan therapy for 12 wk. Renal functions and MAU were determined 12 and 6 wk and just before the treatment as well as sixth and twelfth week of the treatment in all patients. Losartan satisfactorily lowered systemic blood pressure. A significant reduction in MAU was observed from 103 +/- 53 microg/min at the beginning to 59 +/- 25 microg/min in the sixth week and 47 +/- 24 microg/min in the twelfth week (p=0.0007 and 0.0005, respectively). From the sixth week of the treatment, the therapy significantly decreased hemoglobin, hematocrit and erythrocyte levels but did not change mean leukocyte and platelet counts, urea, creatinine levels and creatinine clearances. No serious side-effect was observed during the study. In conclusion, we found that losartan decreased MAU in hypertensive RTx. For that reason, it might be considered as the first choise antihypertensive agent for the renoprotection in selected patients.

The impact of antihypertensive drug groups on urinary albumin excretion in a non-diabetic population

AIMS

Microalbuminuria (30-300 mg 24 h-1) is recognized to be independently associated with renal and cardiovascular risk. Antihypertensives may lower microalbuminuria. We questioned whether the use of different antihypertensive drug classes in general practice influences microalbuminuria as related to blood pressure in nondiabetic subjects.

METHODS

To study this, we used the data from 6836 subjects of an on-going population based study, focused on the meaning of microalbuminuria (PREVEND). Odds ratios, adjusted for age, sex, blood pressure, cholesterol level, smoking and the use of other antihypertensive or cardiovascular drugs, were calculated to determine the association of drug groups with microalbuminuria. Influence of antihypertensives on the relation between blood pressure and (log) urinary albumin excretion was determined by comparing linear regression lines.

RESULTS

Microalbuminuria was significantly associated with the use of dihydropyridine calcium channel blockers (odds ratio: 1.76 [1.22-2.54]), but not with other antihypertensive drug groups. The linear regression line of the relation between blood pressure and (log) urinary albumin excretion was significantly steeper (P = 0.0047) for users of calcium channel blockers, but not for other antihypertensives, compared with subjects using no antihypertensive. Users of a combination of renin-angiotensin system inhibitors and diuretics however, had a less steep regression line (P = 0.037).

CONCLUSIONS

This study suggests a disadvantageous effect of dihydropyridine calcium channel blockers on microalbuminuria compared with other antihypertensive drug groups. Thus, if microalbuminuria is causally related to an increased risk for cardiovascular morbidity and mortality, dihydropyridines do not seem to be agents of choice to lower blood pressure. Furthermore, the combination of renin-angiotensin system inhibition and diuretics seems to act synergistically.

Clinical value of microalbuminuria in hypertension

Microalbuminuria (MA) is a well recognized marker of cardiovascular complications in hypertension, but whether MA can predict adverse outcome in this clinical condition is still a subject for debate. The fact that in hypertensive cohorts those patients who showed an increase in albumin excretion rate also manifested an increased incidence of morbid events indicates that the presence of MA in hypertension may carry an increased cardiovascular risk. However, the prognostic significance of MA remains controversial because no results of prospective studies performed in hypertensive subjects without diabetes mellitus are available. Several factors can affect the prevalence of MA in hypertension, including severity of the disease, selection procedures, concomitant risk factors, degree of obesity, age, and sex distribution. This accounts for the large differences in the prevalence of MA that can be found in the literature, with prevalence rates going from a low of 4.7% to a high of 40%. There is still conflict over whether MA in hypertension is due to increased intraglomerular pressure or to glomerular damage. The data from the literature suggest that in subjects with mild hypertension the main determinant of albumin excretion rate is the haemodynamic load. In subjects with more severe hypertension and hypertensive complications, the augmented urinary albumin leak is probably the consequence of a systemic microvascular disturbance which involves the glomeruli. In this respect, the insulin resistance state often associated to high blood pressure appears as one of the main pathogenetic factors. Whether management of hypertensive populations may be improved by monitoring of albumin excretion rate and whether antihypertensive drugs which are more effective in decreasing urinary albumin can be more beneficial in patients with MA remains to be determined.