Microalbuminuria and hypertension with focus on type 1 and type 2 diabetes

Persistent microalbuminuria after treatment with renin-angiotensin axis blockers: causes and results of treatment intensification

AIMS

The first phase of this study aimed to determine the causes of persistent microalbuminuria after treatment with renin-angiotensin axis (RAA) blocking drugs. In a second phase we tried to determine if strict control of blood pressure and intensive RAA blockade could induce remission or reduction of microalbuminuria in clinical (primary care) practice.

PATIENTS AND METHODS

The study included both diabetic patients and non-diabetic hypertensive patients treated with RAA drugs in the presence of microalbuminuria. 211 patients were recruited (mean age 66.6±11.3 years, 111 men, 117 were diabetic). In the first phase treatment was optimized at standard doses. In the second phase treatment was increased during a three months period to reach a blood pressure (BP) < 130/80 mmHg by adding other antihypertensive treatment and to obtain maximal RAA blockade using long-acting drugs, increased dosage, or adding further medication at night.

RESULTS

Initial mean BP was 141±16/81±11 mmHg. BP control was unsatisfactory (control of systolic blood pressure [SBP] 19.3%; diastolic blood pressure [DBP] 37.6%). Dosage of RAA blocking drugs was inadequate in 21% of patients. Only 27.4% of patients were taking antihypertensive drugs at night. 30.1% of patients took once daily short acting drugs. During the studymean SBP was reduced to 137±13 mmHg (p < .001) and DBP decreased to 79±10 mmHg (p < .001). Control of SBP improved to 24.5% and DBP control went to 44.4%. Mean microalbuminuria decreased from 64.4±47.0 mg/day to 50.1±53.0 mg/day (p < .001) and the prevalence of microalbuminuria was reduced to 59.1%.

CONCLUSIONS

Persistent microalbuminuria was associated with poor blood pressure control and inadequate drug dosage. Low frequency of administration of drugs at night and inappropriate once-daily pills intake were frequent. Strict control of blood pressure and intensive RAA blockade significantly reduced the prevalence of microalbuminuria.

Microalbuminuria is a predictor of chronic renal insufficiency in patients without diabetes and with hypertension: the MAGIC study

BACKGROUND AND OBJECTIVES

Increased urinary albumin excretion is a known risk factor for cardiovascular events and clinical nephropathy in patients with diabetes. Whether microalbuminuria predicts long-term development of chronic renal insufficiency (CRI) in patients without diabetes and with primary hypertension remains to be documented.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted an 11.8-year follow-up of 917 patients who did not have diabetes and had hypertension and were enrolled in the Microalbuminuria: A Genoa Investigation on Complications (MAGIC) cohort between 1993 and 1997. Urinary albumin-to-creatinine ratio (ACR) was assessed at baseline in untreated patients in a core laboratory. Microalbuminuria was defined as ACR > or =22 mg/g in men and ACR > or =31 mg/g in women.

RESULTS

A total of 10,268 person-years of follow-up revealed that baseline microalbuminuria was associated with an increased risk for developing CRI (relative risk [RR] 7.61; 95% confidence interval [CI] 3.19 to 8.16; P < 0.0001), cardiovascular events (composite of fatal and nonfatal cardiac and cerebrovascular events; RR 2.11; 95% CI 1.08 to 4.13; P < 0.028), and cardiorenal events (composite of former end points; RR 3.21; 95% CI 1.86 to 5.53; P < 0.0001). Microalbuminuria remained significantly related to CRI (RR 12.75; 95% CI 3.62 to 44.92; P < 0.0001) and cardiorenal events (RR 2.58; 95% CI 1.32 to 5.05; P = 0.0056) even after adjustment for several baseline covariates.

CONCLUSIONS

Microalbuminuria is an independent predictor of renal and cardiovascular complications in patients without diabetes and with primary hypertension.

Urinary biomarkers involved in type 2 diabetes: a review

Diabetes mellitus is one of the most challenging health concerns of the 21st century. With at least 30% of the diabetic population remaining undiagnosed, effective and early diagnosis is of critical concern. Development of a diagnostic test, more convenient and reliable than those currently used, would therefore be highly beneficial. Urine as a diagnostic medium allows for non-invasive detection of biomarkers, including some associated with type 2 diabetes and its complications. This review provides a synopsis of those urinary biomarkers that potentially may provide a basis for the development of improved diagnostic tests. Three main pathways for the sourcing of potential makers are identified: kidney damage, oxidative stress and low-grade inflammation including atherosclerosis/vascular damage. This review briefly presents each pathway and some of the most relevant urinary biomarkers that may be used to monitor the development or progression of diabetes and its complications. In particular, biomarkers of renal dysfunction such as transferrin, type IV collagen and N-acetyl-beta-D-glucosaminidase might prove to be more sensitive than urinary albumin, the current gold standard, in the detection of incipient nephropathy and risk assessment of cardiovascular disease. Inflammatory markers including orosomucoid, tumour necrosis factor-alpha, transforming growth factor-beta, vascular endothelial growth factor and monocyte chemoattractant protein-1, as well as oxidative stress markers such as 8-hydroxy-2'deoxyguanosine may also be useful biomarkers for diagnosis or monitoring of diabetic complications, particularly kidney disease. However, the sensitivity of these markers compared with albumin requires further investigation.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Prevalence and risk factors of albuminuria in Type 2 diabetes in Bahrain

Microalbuminuria is the earliest sign of diabetic nephropathy, and is a marker of increased diabetic cardiovascular morbidity and mortality. We investigated the prevalence of albuminuria and associated risk factors among Type 2 diabetes (T2DM) patients, who were attending diabetes clinics at primary healthcare facilities in Bahrain. This was a cross-sectional study on 712 adult T2DM Bahraini patients screened for albuminuria using albumin:creatinine ratio test (ACR), in 9 selected primary healthcare centers in Bahrain in the period February-March 2006. Of the 702 participants, 196 (27.9%) were albuminuric. The prevalence of microalbuminuria (ACR>3.4 mg albumin/mmol creatinine) and macroalbuminuria (protein:creatinine ratio >22 mg protein/ mmol creatinine) were 22.0% (no.=155) and 5.8% (no.=41), respectively. Univariate analysis demonstrated significant associations between albuminuria and older age (>65 yr), longer duration of diabetes, high glycated hemoglobin (HbA1c), elevated triglycerides, total- and LDL-cholesterol, systolic (>160 mmHg) and diastolic (>90 mmHg) blood pressure (BP), and retinopathy. Multivariate regression analysis showed that high HbA1c, higher systolic BP, and long duration of diabetes, were significant predictors of albuminuria, while older age, male gender, and higher triglycerides were borderline predictors. Albuminuria in Bahraini T2DM patients was related to poor glycemic control, higher systolic BP, and longer duration of diabetes. Effective preventive and control strategies of those factors should be urgently implemented.

Effect of tight control of HbA1c and blood pressure on cardiovascular diseases in type 2 diabetes: an observational study from the Swedish National Diabetes Register (NDR)

AIM

To estimate hazard ratio (HR) of first incident fatal/non-fatal cardiovascular diseases (CVD) in female/male type 2 diabetic patients, with tight versus adverse control of HbA1c and blood pressure (BP) at baseline, age 30-70 years, no baseline CVD, followed for mean 5.7 years.

METHODS

2593 patients with tight control of HbA1c <7.5% and BP < or = 140/90 mmHg (median 6.5%/130/80 mmHg), and 2160 patients with adverse control 7.5-9.0%/141-190/91-110 mmHg (median 8.1%/155/85 mmHg).

RESULTS

The hazard ratio (HR) for CVD with tight/adverse control was 0.67 (0.55-0.80; p<0.001), adjusting for age, sex, duration, hypoglycaemic treatment, smoking, BMI, lipid-lowering drugs, antihypertensive drugs, microalbuminuria. Adjusted HR for myocardial infarction, coronary heart disease, stroke and total mortality were 0.72 (0.56-0.92; p=0.01), 0.69 (0.55-0.86; p<0.001), 0.62 (0.45-0.84; p<0.001), 1.00 (0.72-1.39). The partial population-attributable risk percent for myocardial infarction, stroke and CVD was 23%, 33%, 29% if adverse HbA1c/BP control could be avoided, while 43%, 38%, 39% with overweight and smoking also avoided. Baseline lower BMI and absence of microalbuminuria were associated with tight control.

CONCLUSION

Median difference of HbA1c/BP 1.6%/25/5 mmHg between tight and adverse control considerably reduced the risk of cardiovascular diseases. The findings call for a multi-factorial approach to improve HbA1c, BP, obesity, smoking, and microalbuminuria.

Diabetic nephropathy

Diabetic nephropathy is the leading cause of chronic renal disease and a major cause of cardiovascular mortality. Diabetic nephropathy has been categorized into stages: microalbuminuria and macroalbuminuria. The cut-off values of micro- and macroalbuminuria are arbitrary and their values have been questioned. Subjects in the upper-normal range of albuminuria seem to be at high risk of progression to micro- or macroalbuminuria and they also had a higher blood pressure than normoalbuminuric subjects in the lower normoalbuminuria range. Diabetic nephropathy screening is made by measuring albumin in spot urine. If abnormal, it should be confirmed in two out three samples collected in a three to six-months interval. Additionally, it is recommended that glomerular filtration rate be routinely estimated for appropriate screening of nephropathy, because some patients present a decreased glomerular filtration rate when urine albumin values are in the normal range. The two main risk factors for diabetic nephropathy are hyperglycemia and arterial hypertension, but the genetic susceptibility in both type 1 and type 2 diabetes is of great importance. Other risk factors are smoking, dyslipidemia, proteinuria, glomerular hyperfiltration and dietary factors. Nephropathy is pathologically characterized in individuals with type 1 diabetes by thickening of glomerular and tubular basal membranes, with progressive mesangial expansion (diffuse or nodular) leading to progressive reduction of glomerular filtration surface. Concurrent interstitial morphological alterations and hyalinization of afferent and efferent glomerular arterioles also occur. Podocytes abnormalities also appear to be involved in the glomerulosclerosis process. In patients with type 2 diabetes, renal lesions are heterogeneous and more complex than in individuals with type 1 diabetes. Treatment of diabetic nephropathy is based on a multiple risk factor approach, and the goal is retarding the development or progression of the disease and to decrease the subject's increased risk of cardiovascular disease. Achieving the best metabolic control, treating hypertension (<130/80 mmHg) and dyslipidemia (LDL cholesterol <100 mg/dl), using drugs that block the renin-angiotensin-aldosterone system, are effective strategies for preventing the development of microalbuminuria, delaying the progression to more advanced stages of nephropathy and reducing cardiovascular mortality in patients with diabetes.

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.

Effects of aggressive approach to the multiple risk factors for diabetic nephro-pathy on proteinuria reduction in diabetes type 2 patients

Dietary interventions with protein and salt restriction, good glucose control, smoking cessation, aggressive blood pressure control, good control of cholesterol and triglycerides, use of ACE inhibitors and ARBs can delay the progression of diabetic nephropathy. The aim of this study was to present the effects of aggressive treatment of the multiple risk factors for diabetic nephropathy on proteinuria in patients with type 2 diabetes. In this study we included 15 patients with diabetes type 2 and insufficient regulation of glycaemia. The patients were followed for three months period. Glycated haemoglobin (HbA1c), fasting plasma glucose (FPG), postprandial plasma glucose (PPG), blood pressure, cholesterol and triglycerides and proteinuria were followed prior and after the study. Prior the study patients were treated with premix insulin divided in two daily doses + metformin after the lunch and they had insufficient regulation of glycaemia. During the study patients were treated with one daily dose of basal insulin, three doses of metformin (2550 mg), one daily dose of atorvastatin (20 mg) and one daily dose of ramipril (5 to 10 mg). Doses of insulin were titrated separately for each patients (0,7-1,0 IU/kg). Patients were advised to start with lifestyle modification, increased physical activity and dietary interventions with protein and salt restriction, energy restricted diet and smoking cessation. A total of 20 patients (male 12 and female 8) with diabetes type 2 were studied. The mean age of the subjects was 53+/-5,25 years. The mean diabetes duration was 4,05+/-1,96 years. The mean body mass index decreased from 28,1+/-1,67 kg/m2 to 25,9 +/-1,22 kg/m2 after the study. Mean HbA1c decreased from 8,82 +/- 0,53 % to 7,15 +/- 0,23 % (p<0,05). Mean fasting glycemia decreased from 8,79+/-0,58 mmol/dm3 to 7,03+/-0,18 mmol/dm3 (p < 0,05). Mean postmeal glycemia decreased from 9,93 +/- 0,77 mmol/dm3 to 7,62 +/- 0,42 mmol/dm3 (p<0,05). The mean cholesterol level decreased from 7,99 +/-0,64 mmol/dm3 to 5,93 +/- 0,65 mmol/dm3 (p<0,05). The mean triglicerides level decreased from 4,05 +/- 0,97 mmol/dm3 to 1,96 +/- 0,24 mmol/dm3 (p<0,05). The significant decrease of proteinuria was recorded, prior the study the mean albuminuria was 1,05 +/- 0,31 g/dm3 and after the study was 0,07 +/- 0,145 g/dm3 (p<0,05). Mean blood pressure prior the study was 153+/-8,69/91,5 +/- 3,78 mm Hg (p<0,05), after the study was 125 +/- 6,32/ 79,25+/-3,26 mmHg. Effective control of glycaemia, blood pressure, cholesterol and triglycerides, use of ACE inhibitors, dietary interventions with protein and salt restriction, smoking cessation, can delay the progression of nephropathy in type 2 diabetes.

Ambulatory pulse pressure, decreased nocturnal blood pressure reduction and progression of nephropathy in type 2 diabetic patients

AIMS/HYPOTHESIS

We followed type 2 diabetic patients over a long period to evaluate the predictive value of ambulatory pulse pressure (PP) and decreased nocturnal BP reduction (non-dipping) for nephropathy progression.

METHODS

Type 2 diabetic patients (n = 112) were followed for an average of 9.5 (range 0.5-14.5) years. At baseline, all patients underwent 24 h ambulatory BP measurement. Urinary albumin excretion rate was evaluated by three urinary albumin:creatinine ratio measurements at baseline and follow-up.

RESULTS

At baseline, patients who subsequently progressed to a more advanced nephropathy stage (n = 35) had reduced diastolic night/day BP variation and higher 24 h systolic BP and PP values; they also had more advanced nephropathy and were more likely to smoke than those with no progression of nephropathy (n = 77). In a Cox regression analysis, independent predictors of nephropathy progression were 24 h PP (p < 0.01), diastolic night:day BP ratio (p = 0.02) and smoking (p = 0.02). The adjusted hazards ratio (95% CI) for each mmHg increment in 24 h PP was 1.04 (1.01-1.07), whereas the adjusted hazards ratio (95% CI) for each 1% increase in diastolic night:day BP ratio was 1.06 (1.01-1.11). Only one of 33 patients (3.0%) with both a diastolic night:day BP ratio and a 24 h PP below the median progressed, whereas 17 of 32 patients (53.1%) with both a diastolic night:day BP ratio and a 24 h PP equal to or above the median progressed to a more advanced nephropathy stage (p < 0.001).

CONCLUSIONS/INTERPRETATION

Ambulatory PP, impaired nocturnal BP decline and smoking are strong, independent predictors of nephropathy progression in type 2 diabetic patients.

The natural course of microalbuminuria among African Americans with type 2 diabetes: a 3-year study

BACKGROUND

The natural course of microalbuminuria in African Americans (AA) with type 2 diabetes is not well established.

METHOD

Longitudinal analysis of 186 African Americans with type 2 diabetes enrolled in Project Sugar, a randomized controlled trial of primary care-based interventions to improve diabetes control.

RESULTS

Mean age was 59.4 years and 85% were female. Mean estimated glomerular filtration rate and urinary albumin-to-creatinine ratio were 75.90 mL/min/1.73 m(2) and 1.62, respectively. Thirty-nine patients had macroalbuminuria and significantly higher systolic blood pressure compared with those with microalbuminuria (P=.01). Sixty patients had microalbuminuria, 19 progressed to macroalbuminuria, and none regressed. Progression was associated significantly with systolic blood pressure >or=115 mm Hg and requirement for blood pressure medication in the univariate model. In the multivariate model, the degree of albumin-to-creatinine ratio (odds ratio 35.51, 95% confidence interval, 2.21-571.65) and need for blood pressure medication (odds ratio 8.96, 95% confidence interval, 1.35-59.70) were independently associated with progression. No association was observed with the use of specific antihypertensive agent.

CONCLUSION

This study suggests that African Americans with type 2 diabetes and microalbuminuria experience irreversible disease that not infrequently progresses to overt proteinuria. The degree of microalbuminuria and blood pressure are key determinants in this process and should be primary targets in treating this population regardless of the antihypertensive class used.

Risk factor control in patients with Type 2 diabetes and coronary heart disease: findings from the Swedish National Diabetes Register (NDR)

AIMS

Patients with Type 2 diabetes and coronary heart disease (CHD) are infrequently treated to risk factor targets in current guidelines. We aimed to examine risk factor management and control levels in a large sample of patients with Type 2 diabetes with CHD.

METHODS

This was an observational study of 1612 patients with first incidence of CHD before 2002, and of 4570 patients with first incidence of CHD before 2005, from the Swedish National Diabetes Register (NDR).

RESULTS

In patients with CHD 1-2 years before follow-up, the achievement of cardiovascular risk factor targets (follow-up 2002/follow-up 2005) was: HbA(1c) < 7%, 47%/54% (P < 0.01); blood pressure < or = 130/80 mmHg, 31%/40% (P < 0.001); total cholesterol < 4.5 mmol/l, 47%/60% (P < 0.001); and low-density lipoprotein-cholesterol < 2.5 mmol/l, 49%/65% (P < 0.001). Use of medication: antihypertensives, 90%/94% (P < 0.01); lipid-lowering drugs, 75%/86% (P < 0.001); and aspirin, 85%/89% (P < 0.05). A high prevalence of adverse lifestyle characteristics prevailed (2002/2005): overweight [body mass index (BMI) > or = 25 kg/m(2)], 86%/85%; obesity (BMI > or = 30 kg/m(2)), 41%/42%; smokers in age group < 65 years, 16-23%/18-19%; as well as waist circumference > or = 102 cm (men) or > or = 88 cm (women), 68% in 2005.

CONCLUSIONS

Patients with a combination of Type 2 diabetes and CHD showed an increased use of lipid-lowering drugs over time, corresponding to improving blood lipid levels. A discrepancy existed between the prevalent use of antihypertensive drugs and the low proportion reaching blood pressure targets. Regretfully, a high prevalence of adverse lifestyle characteristics prevailed. Evidence-based therapy with professional lifestyle intervention and drugs seems urgent for improved quality of secondary prevention in these patients.

Twelve shifting paradigms in diabetic renal disease and hypertension

In the last 30 years we have seen considerable progress in the management of patients with diabetes, in particular with diabetic renal disease. A number of paradigms have been broken down, namely the following, as a consequence, clinical care has improved dramatically. . Significant renal involvement and albuminuria is rare in patients with essential hypertension. 2. High GFR is good for prognosis. 3. Only proteinuric diabetic patients have a poor prognosis. 4. Microalbuminuria only predicts renal disease. 5. Reducing blood pressure may cause low perfusion in the kidney and other organs with long-term negative effect, especially on the glomerular filtration rate. 6. Only in the presence of high blood pressure, should microalbuminuric patients receive anti-hypertensive treatment, including blockade of the RAS. 7. Only reducing blood pressure by blocking RAS in diabetes is relevant and justified. 8. Normoalbuminuria as indicated in the present definition is 'normal'. 9. ACE-I or ARB can only be used separately. 10. Diastolic blood pressure and later systolic pulse pressure are the best parameters for blood pressure recording. 11. Microalbuminuria is the strongest risk marker in patients with type 1 diabetes. 12. Screening for microalbuminuria is relevant, but follow-up was not proposed (also regarding microalbuminuria). In the present situation, it is well-known that patients with essential hypertension may sometimes have microalbuminuria, and it is known that it predicts a poor prognosis. Interestingly, in type 1 diabetes, hyperfiltration is a marker for poor prognosis related to metabolic control. Thus hyperfiltration is a marker for bad development, but microalbuminuria (below the proteinuric level) is also associated with a poor prognosis. It was originally believed that microalbuminuria only predicts renal disease. However, surprisingly it predicts as well cardiovascular disease and early mortality. The story about blood pressure and progression of renal disease is interesting, because it was earlier believed that a certain high blood pressure was mandatory for preservation of the renal function. This appeared to be a completely wrong concept. The data regarding microalbuminuria suggest that patients with microalbuminuria should receive anti-hypertensive treatment, even patients with so-called normal blood pressure. This was confirmed in several trials and also included in the guidelines. Reducing blood pressure is important, but it appeared to be especially beneficial to block the renin-angiontensin system, and it is clear that albuminuria is a continuous variable and is also a risk factor. Earlier it was suggested to use ACE-inhibitors or ARBs. Now it is clear that it is possible to use a combination, with good theoretical background. In the history of hypertension, it was earlier believed that diastolic blood pressure was most important, but later on it was generally accepted that systolic is a better predictor and the goal for treatment and pulse pressure may be even better. Not only is microalbuminuria an important risk marker, but it is as well clear that regression of microalbuminuria is a good marker for a better prognosis in patients. Microalbuminuria is believed to be the strongest risk factor, but new studies actually suggest that a simple parameter such as self-rated health is crucial along with other factors. Regarding new developments, it is clear that new studies have led to several advancements in management in patients, for instance the Steno II study shows positive effect on mortality by multifactorial intervention. Similarly, the ADVANCE study also showed positive effect on mortality by more intensified anti-hypertensive treatment with an ACE-inhibitor. We are eagerly awaiting the results from glucose arm in the ADVANCE study, especially in the light of the ACCORD study showing increased mortality with too strict glycemic control with a goal of 6% in HbA1c.

Clinical Use and Pathogenetic Basis of Laboratory Tests for the Evaluation of Primary Arterial Hypertension

This review focuses on the laboratory biochemical tests that are useful in the diagnostic approach to the hypertensive patient. A "minimal" diagnostic laboratory work-up, including a small number of tests that are simple and relatively inexpensive, is first described. Because these tests provide basic information on the presence of major cardiovascular (CV) risk factors and target organ damage, and might give some clues to the presence of a secondary form of hypertension (HT), they should be performed on all patients presenting with HT. Other tests that are aimed at assessing the overall CV risk, a major determinant of prognosis that dictates the therapeutic strategy in the individual HT patient, are then discussed. They allow identification of major CV risk factors and associated clinical conditions which, if present, lead to a substantial change of therapeutic strategy. The role of C-reactive protein as a marker of atherosclerosis and its predictive value for CV events are also discussed. Finally, a section is devoted to tests that are currently confined to research purposes, such as markers of endothelial function including endothelin-1, homocysteine and genetic analysis.

Review: Cardioprotective effects of telmisartan in uncomplicated and complicated hypertension

The development of angiotensin II receptor blockers (ARB) as a new class of drugs for the management of hypertension has elicited the attention of many clinicians worldwide with the aim of improving blood pressure (BP) control as well as cardiovascular protection.AmongARB telmisartan has been shown to be characterised by an antihypertensive efficacy fully covering the 24-hour period, thereby allowing to antagonise the adverse effects of early morning BP rise on cardiovascular risk. Other specific effects of the drug are represented by its favourable metabolic profile (particularly on insulin sensitivity) and neutral effects on sympathetic cardiovascular function.These properties are coupled with cardioprotective effects, documented by the evidence that the drug: 1) is effective in favouring the regression of cardiac and vascular organ damage, 2) reduces arterial stiffness and improves vascular distensibility and 3) reverses the endothelial dysfunction typical of the hypertensive state particularly when complicated by renal failure, diabetes, obesity or metabolic syndrome. Several of these properties can account for the results of the ONgoing Telmisartan Alone and in combination with Ramipril Global Endpoint Trial (ONTARGET), documenting the beneficial effects on the drug on cardiovascular morbidity and mortality.

Association of microalbuminuria with brachial-ankle pulse wave velocity: the Ohasama study

BACKGROUND

Microalbuminuria is recognized as a marker of generalized vascular dysfunction. However, the associations between microalbuminuria and pulse wave velocity (PWV), carotid intima-media thickness (IMT), and ambulatory blood pressure (ABP), respectively, have not been investigated.

METHODS

Brachial-ankle PWV (baPWV), IMT, and ABP were determined in 328 individuals (mean age, 65.7 +/- 6.4 years) from the general population of Ohasama, a rural Japanese community. The participants were assigned to groups with microalbuminuria and with normoalbuminuria, and their characteristics were compared. We also examined the association between microalbuminuria and baPWV, IMT, and ABP, respectively, using multivariate analyses.

RESULTS

Seventy-nine participants (24%) with microalbuminuria had significantly higher baPWV (P < 0.001) and 24-h systolic BP (SBP) (P = 0.006) than those with normoalbuminuria, although 24-h pulse pressure and mean IMT did not significantly differ between the groups. Multiple logistic regression analyses showed that baPWV, but not 24-h ABP, was independently associated with microalbuminuria (P = 0.002) when adjusted for various confounding factors. After further adjustment for 24-h SBP, the association between baPWV and microalbuminuria remained significant (P = 0.012). The trend was significant even when daytime or nighttime SBP was used instead of 24-hour SBP in this model.

CONCLUSIONS

Microalbuminuria appears to be associated with baPWV more closely than with IMT and ABP, and its association with baPWV is independent of ABP and other cardiovascular risk factors.

Arterial hypertension determined by ambulatory blood pressure profiles: contribution to microalbuminuria risk in a multicenter investigation in 2,105 children and adolescents with type 1 diabetes

OBJECTIVE

Arterial hypertension is a key player in the development of diabetes complications. We used a nationwide database to study risk factors for abnormal 24-h blood pressure regulation and microalbuminuria in children and adolescents with type 1 diabetes.

RESEARCH DESIGN AND METHODS

Ambulatory blood pressure monitoring was performed in 2,105 children and adolescents from 195 pediatric diabetes centers in Germany and Austria. Individual least median squares (LMS)-SD scores were calculated for diurnal and nocturnal systolic (SBP), diastolic (DBP), and mean arterial (MAP) blood pressure according to normalized values of a reference population of 949 healthy German children. The nocturnal blood pressure reduction (dipping) was calculated for SBP as well as DBP.

RESULTS

In diabetic children, nocturnal blood pressure in particular was significantly elevated (SBP +0.51, DBP +0.58, MAP +0.80 LMS-SD) and dipping of SBP DBP, and MAP was significantly reduced (P < 0.0001). Age, diabetes duration, sex BMI, A1C, and insulin dose were related to altered blood pressure profiles; dipping, however, was only affected by age, female sex, and A1C. The presence of microalbuminuria was associated with nocturnal DBP (P < 0.0001) and diastolic dipping (P < 0.01).

CONCLUSIONS

Our observations revealed a clear link between the quality of metabolic control and altered blood pressure regulation even in pediatric patients with short diabetes duration. Nocturnal blood pressure in particular seems to mainly contribute to diabetes complications such as microalbuminuria.

The economic burden of nephropathy in diabetic patients in Germany in 2002

OBJECTIVE

The objective was to describe the resource use and costs due to predefined stages of nephropathy in diabetic patients and to evaluate its economical impact in Germany.

DESIGN AND METHODS

In this retrospective, observational study information about socio-demographics, clinical characteristics and resource use on adult type 1 and type 2 patients with nephropathy in diabetic patients were collected from 23 general practitioners, 10 internists and 24 diabetologists, who were randomly selected from a physicians' database. Based on these results average costs per patient were evaluated for each complication stage from the societal perspective and the perspective of the health insurance.

RESULTS

The costs due to nephropathy in diabetic patients increase dramatically with the progression of the disease. The main cost drivers were dialysis and hospitalization which accounted for 68% of the total costs due to nephropathy in diabetic patients. The total estimated costs related to nephropathy in diabetic patients were euro1332 (from the perspective of the health insurance) and euro2019 from the societal perspective.

CONCLUSION

Patients at high risk should be identified as early as possible and intensive diabetic case management should be provided to them to prevent or decelerate the expensive complications of nephropathy in diabetic patients.

Diabetic nephropathy: mechanisms of renal disease progression

Diabetic nephropathy is characterized by excessive amassing of extracellular matrix (ECM) with thickening of glomerular and tubular basement membranes and increased amount of mesangial matrix, which ultimately progress to glomerulosclerosis and tubulo-interstitial fibrosis. In view of this outcome, it would mean that all the kidney cellular elements, i.e., glomerular endothelia, mesangial cells, podocytes, and tubular epithelia, are targets of hyperglycemic injury. Conceivably, high glucose activates various pathways via similar mechanisms in different cell types of the kidney except for minor exceptions that are related to the selective expression of a given molecule in a particular renal compartment. To begin with, there is an obligatory excessive channeling of glucose intermediaries into various metabolic pathways with generation of advanced glycation products (AGEs), activation of protein kinase C (PKC), increased expression of transforming growth factor-beta (TGF-beta), GTP-binding proteins, and generation of reactive oxygen species (ROS). The ROS seem to be the common denominator in various pathways and are central to the pathogenesis of hyperglycemic injury. In addition, there are marked alterations in intraglomerular hemodynamics, i.e., hyperfiltration, and this along with metabolic derangements adversely compounds the hyperglycemia-induced injury. Here, the information compiled under various subtitles of this article is derived from an enormous amount of data summarized in several excellent literature reviews, and thus their further reading is suggested to gain in-depth knowledge of each of the subject matter.

Blood pressure means rather than nocturnal dipping pattern are related to complications in Type 2 diabetic patients

AIM

To determine whether systolic and diastolic blood pressure (BP) means, during ambulatory BP monitoring (ABPM), are more strongly correlated with microvascular complications and echocardiographic structural alterations than night-time/daytime (N/D) BP ratio.

METHODS

A cross-sectional study was conducted in 270 Type 2 diabetes mellitus (DM) outpatients who underwent clinical and laboratory investigations, urinary albumin excretion rate (UAER) determination, echocardiography, office and 24-h ABPM (Spacelabs 90207).

RESULTS

UAER, after multivariate adjustments, was associated with office BP (systolic: R(2)(a) 0.162, P < 0.001; diastolic: R(2)(a) 0.124, P < 0.001) and ABPM (24-h systolic: R(2)(a) 0.195, P < 0.001; 24-h diastolic: R(2)(a) 0.197, P < 0.001) but not with N/D BP ratios (systolic: R(2)(a) 0.062, P = 0.080; diastolic: R(2)(a) 0.063, P = 0.069). Similar results were observed for echocardiographic parameters. The presence of retinopathy was associated only with night-time BP values [systolic means: odds ratio (OR) 1.13, 95% confidence interval (CI) 1.03-1.24 and diastolic means: OR 1.21, CI 1.04-1.40 and N/D diastolic BP ratio > 0.90, OR 3.21, CI 1.65-6.25].

CONCLUSIONS

UAER and echocardiographic structural alterations had more consistent correlations of a greater magnitude with systolic BP means than with N/D BP ratios. The nocturnal BP values appear to be more relevant for diabetic retinopathy. BP measurement in patients with Type 2 DM should take into account the 24-h period rather than focusing on a specific time span of BP homeostasis.

Interactions between microvascular and macrovascular disease in diabetes: pathophysiology and therapeutic implications

Convention partitions the complications of diabetes into two main subtypes. First are the diabetes-specific microvascular complications of retinopathy, nephropathy and neuropathy; second are the atherothrombotic macrovascular complications that account for the majority of premature deaths. Pathological interactions between microvascular and macrovascular complications, for example, nephropathy and macrovascular disease, are common. Similar mechanisms and shared risk factors drive the development and progression of both small and large vessel disease. This concept has therapeutic implications. Mounting evidence points to the need for multifactorial strategies to prevent vascular complications in subjects with diabetes and/or the metabolic syndrome. We advocate a combined therapeutic approach that addresses small and large vessel disease. Preferential use should be made of drug regimens that (i) maximize vascular protection, (ii) reduce the risk of iatrogenic vascular damage and (iii) minimize the increasing problem of polypharmacy.

Reduction in microalbuminuria as an integrated indicator for renal and cardiovascular risk reduction in patients with type 2 diabetes

OBJECTIVE

Microalbuminuria in diabetic patients is a predictor for diabetic nephropathy and cardiovascular disease. The aim of this study is to investigate the clinical impact of reducing microalbuminuria in type 2 diabetic patients in an observational follow-up study.

RESEARCH DESIGN AND METHODS

We enrolled 216 type 2 diabetic patients with microalbuminuria during an initial 2-year evaluation period and observed them for the next 8 years. Remission and a 50% reduction of microalbuminuria were defined as a shift to normoalbuminuria and a reduction <50% from the initial level of microalbuminuria. The association between reducing microalbuminuria and first occurrence of a renal or cardiovascular event and annual decline rate of estimated glomerular filtration rate (eGFR) was evaluated.

RESULTS

Twelve events occurred in 93 patients who attained a 50% reduction of microalbuminuria during the follow-up versus 35 events in 123 patients without a 50% reduction. The cumulative incidence rate of events was significantly lower in patients with a 50% reduction. A pooled logistic regression analysis revealed that the adjusted risk for events in subjects after a 50% reduction was 0.41 (95% CI 0.15-0.96). In addition, the annual decline rate of eGFR in patients with a 50% reduction was significantly slower than in those without such a reduction. The same results were also found in the analysis regarding whether remission occurred.

CONCLUSIONS

The present study provides clinical evidence implying that a reduction of microalbuminuria in type 2 diabetic patients is an integrated indicator for renal and cardiovascular risk reduction.

Electrophoretic determination of albumin in urine using on-line concentration techniques

To improve the sensitivity of the UV-detection for the determination of trace amounts of albumin by capillary zone electrophoresis (CZE), five on-line preconcentration techniques, including field-amplified sample stacking (FASS), head-column field-amplified sample stacking (HC-FASS), stacking with a polymer solution, dynamic pH junction and large volume sample stacking (LVSS) with reversed polarity, were compared. Sensitivity enhancement factor and reproducibility were two factors that were used to assess the suitability of each method. To minimize protein adsorption on the capillary wall, capillaries were covalently modified with anionic polymer, poly(sulfopropylmethacrylate) coating. All used methods have good reproducibility. The maximum sensitivity enhancement factor (about 67-fold in terms of peak heights) was achieved with LVSS technique. The concentration limit of detection (LOD) (S/N=3) for the human serum albumin obtained with the optimized LVSS approach was 15 microg/ml with UV-detection. The method was further evaluated for the analysis of urine samples with gel-filtration-based sample-desalting procedure.

Nefropatia diabética e doença cardíaca

Pacientes em diferentes estágios de nefropatia diabética (ND) apresentam freqüentemente comprometimento cardíaco expresso por isquemia miocárdica e/ou cardiomiopatia diabética. Estas alterações já estão presentes em estágios iniciais da ND e provavelmente mesmo antes de a excreção urinária de albumina (EUA) atingir níveis tradicionalmente diagnósticos de microalbuminúria. As alterações cardíacas são responsáveis por uma proporção significativa de mortes nos pacientes com ND e podem ser reduzidas através de intervenção nos múltiplos fatores de risco cardiovascular encontrados nesses pacientes. A avaliação de doença cardíaca deve idealmente ser realizada em todos os pacientes com qualquer grau de ND através de métodos específicos para detectar isquemia e disfunção miocárdica, além do emprego rotineiro da monitorização ambulatorial da pressão arterial em 24 h. Em pacientes com aterosclerose avançada também devem ser avaliadas outras artérias (carótidas, aorta, renais). O tratamento rigoroso da hipertensão arterial, o uso de fármacos cardioprotetores, o tratamento da dislipidemia e da anemia, assim como o emprego de medicamentos anti-plaquetários, poderão reduzir a elevada mortalidade cardiovascular na ND.

Glycemic and risk factor control in type 1 diabetes: results from 13,612 patients in a national diabetes register

OBJECTIVE

This study was designed to investigate the clinical characteristics of a large type 1 diabetic population and to evaluate the degree of fulfillment of recently updated treatment goals.

RESEARCH DESIGN AND METHODS

The Swedish National Diabetes Register was initiated in 1996 as a tool for quality assurance in diabetes care. A1C levels, treatment, and risk factors were analyzed in two cross-sectional samples of 9,424 patients in 1997 and 13,612 patients in 2004 and in a smaller longitudinal sample from 1997 to 2004.

RESULTS

Mean A1C decreased from 8.2 +/- 1.3% in 1997 to 8.0 +/- 1.2% in 2004 (P < 0.001). The proportion of patients reaching A1C <7.0% increased from 17.4 to 21.2% in 2004. A slow but significant improvement in blood pressure levels was seen, but only 61.3% reached the blood pressure goal of <130/80 mmHg in 2004. Lipid control improved, and the use of lipid-lowering drugs increased. Among patients treated with lipid-lowering agents, 38% reached the goal of total cholesterol <4.5 mmol/l, and 48% reached the goal of LDL cholesterol <2.5 mmol/l. Successful long-term glycemic and blood pressure control were both independently predicted by low BMI and the absence of microalbuminuria in 1997.

CONCLUSIONS

In this large cohort of type 1 diabetic patients, there was a slow improvement in glycemic and risk factor control from 1997 to 2004, although the gap between the clinical results and current Swedish and American treatment goals is still unsatisfactory. It is crucial that additional measures be taken to improve risk factor control in type 1 diabetic patients.

Preventing microalbuminuria in patients with type 2 diabetes

The public health burden of type 2 diabetes mellitus has been dramatically increasing world-wide. The chronic complications of type 2 diabetes play an important role in decreasing life expectancy and adversely affecting quality of life. Diabetic nephropathy, which is originally microvascular in nature, is widely considered an important complication of diabetes. In prospective clinical investigations, increased urinary albumin excretion proved to be associated not only with subsequent renal outcomes but also with cardiovascular morbidity/mortality independently of other risk factors. Therefore, microalbuminuria as an early sign of increased urinary albumin excretion should be considered important for both treatment and even for prevention. Preventing microalbuminuria might diminish progression to overt nephropathy and, hopefully, might limit cardiovascular events. Regarding primary prevention of diabetic nephropathy, therapeutic intervention should optimally be initiated at the stage of normoalbuminuria. Although additional factors such as smoking cessation, reduction of protein intake, and treatment of lipid abnormalities are important, providing optimal diabetic control as well as targeting optimal blood pressure are the key elements of a prevention strategy in diabetic patients. Recently, the Bergamo Nephrologic Diabetes Complications Trial (BENEDICT) documented that a significant decrease of the development of persistent microalbuminuria could be achieved by using an ACE-inhibitor, trandolapril alone or in combination with verapamil SR, a non-dihydropyridine calcium-channel blocker in hypertensive type 2 diabetic patients with normoalbuminuria. The results of this primary-prevention strategy should be corroborated by further investigations to determine whether these beneficial changes could later result in improvement of renal clinical outcomes, macrovascular complications, or both.

Microalbuminuria among Type 1 and Type 2 diabetic patients of African origin in Dar Es Salaam, Tanzania

Background

The prevalences and risk factors of microalbuminuria are not full described among black African diabetic patients. This study aimed at determining the prevalence of microalbuminuria among African diabetes patients in Dar es Salaam, Tanzania, and relate to socio-demographic features as well as clinical parameters.

Methods

Cross sectional study on 91 Type 1 and 153 Type 2 diabetic patients. Two overnight urine samples per patient were analysed. Albumin concentration was measured by an automated immunoturbidity assay. Average albumin excretion rate (AER) was used and were categorised as normalbuminuria (AER < 20 ug/min), microalbuminuria (AER 20–200 ug/min), and macroalbuminuria (AER > 200 ug/min). Information obtained also included age, diabetes duration, sex, body mass index, blood pressure, serum total cholesterol, high-density and low-density lipoprotein cholesterol, triglycerides, serum creatinine, and glycated hemoglobin A_1c.

Results

Overall prevalence of microalbuminuria was 10.7% and macroalbuminuria 4.9%. In Type 1 patients microalbuminuria was 12% and macroalbuminuria 1%. Among Type 2 patients, 9.8% had microalbuminuria, and 7.2% had macroalbuminuria. Type 2 patients with abnormal albumin excretion rate had significantly longer diabetes duration 7.5 (0.2–24 yrs) than those with normal albumin excretion rate 3 (0–25 yrs), p < 0.001. Systolic and diastolic blood pressure among Type 2 patients with abnormal albumin excretion rate were significantly higher than in those with normal albumin excretion rate, (p < 0.001).

No significant differences in body mass index, glycaemic control, and cholesterol levels was found among patients with normal compared with those with elevated albumin excretion rate either in Type 1 or Type 2 patients.

A stepwise multiple linear regression analysis among Type 2 patients, revealed AER (natural log AER) as the dependent variable to be predicted by [odds ratio (95% confidence interval)] diabetes duration 0.090 (0.049, 0.131), p < 0.0001, systolic blood pressure 0.012 (0.003–0.021), p < 0.010 and serum creatinine 0.021 (0.012, 0.030).

Conclusion

The prevalence of micro and macroalbuminuria is higher among African Type 1 patients with relatively short diabetes duration compared with prevalences among Caucasians. In Type 2 patients, the prevalence is in accordance with findings in Caucasians. The present study detects, however, a much lower prevalence than previously demonstrated in studies from sub-Saharan Africa. Abnormal AER was significantly related to diabetes duration and systolic blood pressure.

A Sensitized Screen of N-ethyl-N-nitrosourea–Mutagenized Mice Identifies Dominant Mutants Predisposed to Diabetic Nephropathy

Diabetic nephropathy (DN) is a late diabetic complication that comprises progressively increasing albuminuria, declining GFR, and increased cardiovascular risk. Only a minority of patients with diabetes (25 to 40%) develop nephropathy, and there is evidence that heritable genetic factors predispose these "at-risk" individuals to DN. Comparing variability among inbred mouse strains with respect to a specific phenotype can model interhuman variability, and each strain represents a genetically homogeneous system with a defined risk for nephropathy. C57BL/6 mice, which are relatively resistant to DN, were mutagenized using N-ethyl-N-nitrosourea and screened for mutants that developed excess albuminuria on a sensitizing type 1 diabetic background contributed by the dominant Akita mutation in insulin-2 gene (Ins2(Akita)). Two of 375 diabetic G1 founders were found to exhibit albumin excretion rates persistently 10-fold greater than albumin excretion rates in nonmutagenized Ins2(Akita) controls. This albuminuria trait was heritable and transmitted to approximately 50% of Ins2(Akita) G2 and G3 progeny, consistent with a simple, dominantly inherited trait, but was never observed in nondiabetic offspring. During the course of 1 yr, albuminuric Ins2(Akita) G2 and G3 progeny developed reduced inulin clearance with elevated blood urea nitrogen and plasma creatinine. Glomerular histology revealed mesangial expansion, and glomerular basement membrane thickening as determined by electron microscopy was enhanced in diabetic mutant kidneys. Hereditary albuminuric N-ethyl-N-nitrosourea-induced mutants were redesignated as Nphrp1 (nephropathy1) and Nphrp2 (nephropathy2) mice for two generated lines. These novel mutants provide new, robust mouse models of DN and should help to elucidate the underlying genetic basis of predisposition to DN.

Diabetic nephropathy: leveraging mouse genetics

PURPOSE OF REVIEW

Advances in mouse genetics have made this species particularly useful as a model for human disease. This review will summarize recent advances regarding the pathogenesis of diabetic nephropathy discovered in mice.

RECENT FINDINGS

Diabetic nephropathy has been characterized in novel genetic models of murine diabetes including the Akita, Ove26, and ICER-Igamma mice. Mutagenesis resources targeting every gene of the genome and the importance of inbred genetic background are discussed.

SUMMARY

Through the use of these resources mouse models should provide new insight into the pathogenesis of diabetic nephropathy, and complement human studies and validate the identity of candidate genes contributing to diabetic nephropathy.

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.

Prognostic significance of the white coat hypertension in patients with type 1 diabetes mellitus

Despite the high prevalence of white coat hypertension (WCH) in diabetes mellitus and the evidence that hypertension is a clear risk factor for the development of microalbuminuria (MA) in these patients, there is no information on the long-term prognostic significance of this condition in the diabetic population. We studied the evolution of 40 patients with type 1 diabetes mellitus (Type 1 DM). Twenty patients with WCH (office blood pressure> or =140/90mmHg associated with mean daytime blood pressure<135/85mmHg) classified as the WCH group and 20 patients with type 1 DM with a similar age and disease evolution, but who were normotensive, (office blood pressure<140/90mmHg associated with mean daytime blood pressure<135/85mmHg) classified as the normotensive control group. After 5 years of follow-up, MA appeared in four subjects and sustained hypertension in another, with a total of 31% of events in the WCH group, with none in the normotensive group. Kaplan-Meier analysis showed that the relative risk of developing these hypertensive events was 25% higher in the WCH group. At baseline, the night time systolic and diastolic blood pressure levels were significantly higher in patients who further developed MA and sustained hypertension. The findings in this study highlight the clinical importance of careful follow-up of type 1 diabetic patients with WCH.

Macroalbuminuria is a better risk marker than low estimated GFR to identify individuals at risk for accelerated GFR loss in population screening

Macroalbuminuria, erythrocyturia, and impaired renal function are strong predictors of poor renal outcome in patients with known renal disease. However, the yield of mass screening for these variables to identify individuals who are at risk for GFR loss is yet unknown in a Western population. With the use of data from the Prevention of Renal and Vascular End-Stage Disease (PREVEND) study, a prospective, population-based cohort study, the cardiovascular and renal prognosis was investigated in patients with classical renal risk markers: Macroalbuminuria (> or =300 mg albumin/24 h urine), erythrocyturia (> or =250 erythrocytes/L, without leukocyturia), and impaired renal function (both 24-h creatinine clearance and Modification of Diet in Renal Disease clearance below the fifth percentile of age- and gender-matched control subjects). The 8592 patients who were included in this study were followed for a 4-yr period. We identified 134 patients with macroalbuminuria, 128 with erythrocyturia, and 103 with impaired renal function. There was only a little overlap among the three groups. The prevalence of macroalbuminuria, erythrocyturia, and impaired renal function was calculated to be in the general population 0.6, 1.3, and 0.9%, respectively. In all three groups, fewer than 30% of patients were known to have this laboratory abnormality before screening. The incidence of cardiovascular disease was high in the macroalbuminuria group (e.g., the age- and gender-adjusted hazard ratio for mortality as a result of cardiovascular disease is 2.6 [1.1 to 6.0]) and for the impaired renal function group (3.4 [1.5 to 8.0]). After a mean follow-up of 4.2 yr, the macroalbuminuria group showed a -7.2 ml/min per 1.73 m2 estimated GFR (eGFR) loss, compared with -2.3 ml/min per 1.73 m2 in the control group (difference P < 0.001), whereas the rate of eGFR loss in the impaired renal function group (-0.2 ml/min per 1.73 m2; P = 0.18) and the erythrocyturia group (-2.6 ml/min per 1.73 m2) was not different from the control group. Macroalbuminuria and impaired renal function both predict a worse prognosis with respect to cardiovascular morbidity and mortality. However, macroalbuminuria is a better risk marker than low eGFR or erythrocyturia to identify in population screening of individuals who are at risk for accelerated GFR loss.

Chromosomal telomere attrition as a mechanism for the increased risk of epithelial cancers and senescent phenotypes in type 2 diabetes

Telomeres are the repeat DNA sequences at the end of chromosomes necessary for successful DNA replication and chromosomal integrity. Telomeres shorten at cell division at a rate determined by oxidative DNA damage, and cells are triggered into replicative senescence once telomeres shorten to a critical length. Telomere-related chromosomal maintenance also has a role in carcinogenesis. Type 2 diabetes is characterised by increased oxidative stress, increased oxidative DNA damage, senescent retinal and renal phenotypes, and an increased risk of epithelial malignancy. We suggest that increased oxidative DNA damage and telomere attrition in type 2 diabetes leads to: (1) carcinogenic telomere-dependent chromosomal non-reciprocal translocations, genomic instability, and the development of epithelial cancers; (2) senescent retinal and renal phenotypes (expressed as diabetic retinopathy and nephropathy); and (3) senescent vascular endothelial, monocyte-macrophage and vascular smooth muscle cells (expressed as endothelial dysfunction and accelerated atherogenesis). An adverse intrauterine environment leads to increased feto-placental oxidative stress and feto-placental oxidative DNA damage. We also suggest that intrauterine oxidative DNA damage and telomere shortening is another point at which increased oxidative stress could contribute to a pre-programmed increased risk of senescent phenotypes in adult offspring, characterised by type 2 diabetes and epithelial malignancy. These suggestions can be used to understand early glucose intolerance in the young children of type 1 diabetes pregnancies, poor cancer outcomes in type 2 diabetes, beta cell fatigue in type 2 diabetes and the absence of increased epithelial cancer risk in type 1 diabetes.

Evidence for renoprotection by blockade of the renin-angiotensin-aldosterone system in hypertension and diabetes

The incidence of end-stage renal disease (ESRD) is rising worldwide, accompanied by corresponding increases in the risk of morbidity and mortality. Underlying this trend are increasing rates of hypertension and diabetes mellitus, the two most common causes of ESRD. In addition to the adverse haemodynamic effects of hypertension on the kidney, elevated blood pressure (BP) can activate components of the renin-angiotensin-aldosterone system (RAAS), which, in turn, activate mediators of inflammation, oxidative stress, cell growth, and matrix accumulation. Lowering BP reduces the risk of cardiovascular events and renal damage. Accumulating evidence from clinical and laboratory studies suggests that interrupting the RAAS with therapies such as angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, and aldosterone receptor blockers can interfere with the mechanisms that promote diabetic and non-diabetic renal damage. Moreover, clinical trials of RAAS blockade have demonstrated reductions in microalbuminuria, a predictor of increased cardiorenal risk and overt nephropathy in patients with and without diabetes and/or hypertension. In this way, agents that block the RAAS should be considered the drugs of first choice as they provide enhanced renoprotection compared with other classes of antihypertensive agents such as calcium channel blockers and beta-blockers.

Albuminuria as a marker of the risk of developing type 2 diabetes in non-diabetic Aboriginal Australians

BACKGROUND

Aboriginal Australians experience a higher risk of diabetes than the general Australian population. In this paper, we conducted a nested case-control study to determine whether the presence of microalbuminuria and macroalbuminuria is associated with the development of diabetes among diabetes-free Aboriginal people at baseline.

METHODS

Urine albumin to creatinine ratios (ACRs) were obtained from 882 Aboriginal people aged 20-74 years from one community. Among them 750 were free of either clinical known diabetes or newly diagnosed diabetes according to WHO 1999 criteria. Over an 11 year follow-up period, 117 participants developed diabetes. They were defined as cases. Each case was matched by an individual control with same sex and body mass index (BMI) category, and age within 2 years. Conditional logistic regression was used to assess the association between albuminuria and diabetes.

RESULTS

The baseline level of ACR was significantly higher among cases than among controls. The odds ratios for future diabetes were 2.36 [95% confidence interval (95% CI) 1.01-5.50] and 3.27 (95% CI 1.38-7.77) for middle and upper tertiles, respectively, with adjustment for age, BMI, serum total cholesterol, serum C-reactive protein values, and fasting plasma glucose at the baseline. The adjusted odds ratios were 1.90 (95% CI 0.88-4.06) and 2.51 (95% CI 1.08-5.87) for those with microalbuminuria and macroalbuminuria, respectively.

CONCLUSIONS

The presence of microalbuminuria and macroalbuminuria predicts diabetes independent of other known risk markers of development of type 2 diabetes in Aboriginal people.

Does microalbuminuria predict illness severity in critically ill patients on the intensive care unit? A systematic review

CONTEXT

Studies assessing the accuracy of microalbuminuria to predict illness severity on the intensive care unit have produced inconsistent results.

OBJECTIVE

To determine the diagnostic accuracy of microalbuminuria to predict illness severity in critically ill patients on the intensive care unit.

DATA SOURCE

MEDLINE (1951 to September 2004) and EMBASE (1980 to September 2004) electronic databases were searched for relevant studies. Reference lists of all abstracts were manually searched to identify studies not included in the electronic database.

STUDY SELECTION

Studies that prospectively evaluated the accuracy of microalbuminuria to predict illness severity and/or mortality probability in adult patients on the intensive care unit were selected.

DATA EXTRACTION

We included nine studies in the review. Data to evaluate methodological quality and results were abstracted.

DATA SYNTHESIS

The methodological quality of a number of studies was poor. Significant heterogeneity in the design and conduct of the studies circumvented the data being subjected to meta-analysis. Studies also differed in the timing of the index test, in the methods of quantifying microalbuminuria, and in the cutoff values used.

CONCLUSIONS

This descriptive analysis reveals that microalbuminuria may hold promise as a predictor of illness severity and mortality on the intensive care unit. However, future epidemiologic studies need to be conducted to determine the optimal timing as well as the threshold reference value for the urine albumin creatinine ratio in the adult intensive care unit population. Thereafter, multiple-center prospective epidemiologic studies must be conducted to confirm and validate the findings of these preliminary studies. Future studies should conform to the Standards for Reporting of Diagnostic Accuracy checklist in terms of study design, conduct, and reporting. Presently there is no evidence to warrant the use of this tool on the intensive care unit.

[Blood pressure homeostasis and microvascular complications in diabetic patients]

The retinopathy and nephropathy are among the most prevalent and disabling complications associated to microvascular damage in diabetes mellitus. The severity of hyperglycaemia and the presence of arterial systemic hypertension are among the main risk factors for these complications. The ambulatory blood pressure provided a better understanding of patterns of blood pressure in diabetic patients. There is a growing number of evidence relating diabetic patients with abnormal 24 h blood pressure patterns. Even subtle modifications of these patterns, frequently shown by patients diagnosed as normotensives in office blood pressure measurings, may be implicated in an increased risk of microvascular complications. Hyperglycaemia and these abnormal pressure patterns appear to have a synergistic effect on promoting and aggravating diabetic retinopathy. Impairment of the normal retinal autoregulation is one of the implicated physiopathological mechanisms. Probably, ABP may be useful in predicting an increased risk of microvascular complications on diabetic normotensive patients. The objective of this paper is to provide an updated and clinically oriented review in blood pressure homeostasis and diabetes mellitus.

Streptozotocin (STZ) diabetes enhances benzo(alpha)pyrene induced renal injury in Sprague Dawley rats

Information is lacking regarding the biological response to environmental chemicals in the context of pre-existing disease. Benzo(alpha)pyrene (BaP), a polycyclic aromatic hydrocarbon, is a byproduct of combustion that causes renal injury and elicits a nephropathic response. This study evaluated the nephrotoxicity of BaP in normoglycemic and diabetic rats. Female Sprague Dawley rats were divided into four groups: normoglycemic-vehicle (NV), normoglycemic-BaP (N-BaP), diabetic-vehicle (DV) and diabetic-BaP (D-BaP). Diabetes was induced by intraperitoneal (ip) injection of streptozotocin (60 mg/kg, 1 ml/kg). Rats were injected (ip) with vehicle or 10 mg/kg BaP (1 ml/kg) once per week for 5 weeks. Urinary protein and albumin, plasma creatinine and light microscopy were performed to assess the effects of BaP on kidney function. Diabetes was confirmed by plasma glucose levels >400 mg/dl in the DV and D-BaP groups. BaP increased kidney weight and blood urea nitrogen (BUN) levels in the D-BaP relative to the DV group. No change in BUN was observed following 5 weeks of BaP treatment in the normoglycemic animals, however, kidney weight was increased (p=0.013) in the N-BaP relative to the NV animals. STZ diabetes increased susceptibility to BaP mediated renal damage following repeated treatment for 5 weeks when compared to age matched normoglycemic rats.

Angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers for prevention and treatment of nephropathy associated with type 2 diabetes mellitus

Renal complications resulting from type 2 diabetes mellitus are costly and common. Finding optimal therapy is important for the prevention and management of diabetic nephropathy. Research has focused on antihypertensive agents that modify the renin-angiotensin-aldosterone system. Because of their effects on the glomerulus, angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) have been studied as interventions at various stages of diabetic nephropathy. The ACE inhibitors may delay the progression to microalbuminuria and then clinical albuminuria. The ARBs decrease albuminuria in patients with microalbuminuria and decrease adverse renal events, specifically the progression to end-stage renal disease in patients with clinical albuminuria and hypertension. Limited data suggest that combination therapy with ACE inhibitors and ARBs may slow the progression of microalbuminuria to clinical albuminuria. Because of the variability in degree of albuminuria evaluated and in study designs (numbers of patients, study duration, drug dosages, and outcomes measured), a detailed review of the available literature about ACE inhibitors and ARBs in the prevention or treatment of diabetic nephropathy may provide insight to clinicians.

Beneficial effect of lisinopril plus telmisartan in patients with type 2 diabetes, microalbuminuria and hypertension

Angiotensin-converting enzyme (ACE) inhibitors have favourable effects on hypertension and diabetic nephropathy, but persistent use may result in incomplete blockade of the renin-angiotensin system. Long-term effects of dual blockade using the ACE inhibitor lisinopril and the long-acting angiotensin II receptor blocker (ARB) telmisartan on blood pressure and albumin excretion rate (AER) were evaluated. Patients with type 2 diabetes mellitus, hypertension (systolic blood pressure [SBP] >or=140 mmHg or diastolic blood pressure [DBP] >or=90 mmHg) and microalbuminuria (AER 30-300 mg/24h) received 20mg of lisinopril or 80 mg of telmisartan once a day for 24 weeks. Patients were then randomised to continuing treatment with the respective monotherapy or with lisinopril plus telmisartan for a further 28 weeks. Significant (P<0.001) declines in SBP (11.1 mmHg versus 10.0 mmHg), DBP (5.6 mmHg versus 5.3 mmHg) and AER (98 mg/24 h versus 80 mg/24 h) were achieved with lisinopril (n=95) or telmisartan (n=97), respectively, after 24 weeks. Subsequent treatment with lisinopril plus telmisartan for 28 weeks resulted in further significant reductions (P<0.001) in SBP, DBP and AER compared with either monotherapy. All treatments were well tolerated. Lisinopril plus telmisartan thus provides superior blood pressure and AER control than either monotherapy. We conclude that use of dual blockade may provide a new approach to prevention of diabetic nephropathy in patients with type 2 diabetes, hypertension and microalbuminuria.

Albuminuria and incident coronary heart disease in Australian Aboriginal people

BACKGROUND

It has been suggested that albuminuria is useful in identifying persons at increased risk of coronary heart disease (CHD). Australian Aborigines have exceedingly high rates of renal failure together with increased CHD mortality. We undertook this prospective cohort study to assess the independent effect of albuminuria on CHD risk in Aboriginal people in the Northern Territory of Australia.

METHODS

We examined the relation between micro- and macroalbuminuria and incident CHD in a sample of 870 Aboriginal adults aged 20 to 74 years old without prevalent baseline CHD. Cox proportional hazards models were used to assess the association between baseline albuminuria and CHD incidence.

RESULTS

During a median of 9.2 years of follow-up, 89 CHD events occurred during the follow-up period (1992 to 2003). The incidence of CHD increased significantly across categories of albuminuria (4.4, 10.9, and 29.8 per 1000 person-years for normoalbuminuria, microalbuminuria, and macroalbuminuria, respectively). The multiple Cox proportional hazards regression showed the hazard ratio was 3.4 (95% CI 1.6, 7.3), adjusting for age, gender, body mass index (BMI), blood pressure, total cholesterol, diabetes status, cigarette smoking, and alcohol consumption, for macroalbuminuria group. Hazard ratio for microalbuminuria group was not significantly different from unity during the first 6 years of follow-up but significantly higher during the follow-up period > or = 6 years with adjusted hazard ratio 9.0 (95% CI 2.0, 40.0).

CONCLUSION

Independent of traditional cardiovascular risk factors, both microalbuminuria and macroalbuminuria may be useful in identifying persons at increased risk of CHD in Aboriginal people.