Microalbuminuria in prediction and prevention of diabetic nephropathy in insulin-dependent diabetes mellitus patients

Angiotensin-converting-enzyme inhibitors and angiotensin receptor blockers for preventing the progression of diabetic kidney disease

BACKGROUND

Guidelines suggest that adults with diabetes and kidney disease receive treatment with angiotensin-converting-enzyme inhibitors (ACEi) or angiotensin receptor blockers (ARB). This is an update of a Cochrane review published in 2006.

OBJECTIVES

We compared the efficacy and safety of ACEi and ARB therapy (either as monotherapy or in combination) on cardiovascular and kidney outcomes in adults with diabetes and kidney disease.

SEARCH METHODS

We searched the Cochrane Kidney and Transplants Register of Studies to 17 March 2024 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal, and ClinicalTrials.gov.

SELECTION CRITERIA

We included studies evaluating ACEi or ARB alone or in combination, compared to each other, placebo or no treatment in people with diabetes and kidney disease.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed the risk of bias and extracted data. Summary estimates of effect were obtained using a random-effects model, and results were expressed as risk ratios (RR) and their 95% confidence intervals (CI) for dichotomous outcomes and mean difference (MD) or standardised mean difference (SMD) and 95% CI for continuous outcomes. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

One hundred and nine studies (28,341 randomised participants) were eligible for inclusion. Overall, the risk of bias was high. Compared to placebo or no treatment, ACEi may make little or no difference to all-cause death (24 studies, 7413 participants: RR 0.91, 95% CI 0.73 to 1.15; I2 = 23%; low certainty) and with similar withdrawals from treatment (7 studies, 5306 participants: RR 1.03, 95% CI 0.90 to 1.19; I2 = 0%; low certainty). ACEi may prevent kidney failure (8 studies, 6643 participants: RR 0.61, 95% CI 0.39 to 0.94; I2 = 0%; low certainty). Compared to placebo or no treatment, ARB may make little or no difference to all-cause death (11 studies, 4260 participants: RR 0.99, 95% CI 0.85 to 1.16; I2 = 0%; low certainty). ARB have uncertain effects on withdrawal from treatment (3 studies, 721 participants: RR 0.85, 95% CI 0.58 to 1.26; I2 = 2%; low certainty) and cardiovascular death (6 studies, 878 participants: RR 3.36, 95% CI 0.93 to 12.07; low certainty). ARB may prevent kidney failure (3 studies, 3227 participants: RR 0.82, 95% CI 0.72 to 0.94; I2 = 0%; low certainty), doubling of serum creatinine (SCr) (4 studies, 3280 participants: RR 0.84, 95% CI 0.72 to 0.97; I2 = 32%; low certainty), and the progression from microalbuminuria to macroalbuminuria (5 studies, 815 participants: RR 0.44, 95% CI 0.23 to 0.85; I2 = 74%; low certainty). Compared to ACEi, ARB had uncertain effects on all-cause death (15 studies, 1739 participants: RR 1.13, 95% CI 0.68 to 1.88; I2 = 0%; low certainty), withdrawal from treatment (6 studies, 612 participants: RR 0.91, 95% CI 0.65 to 1.28; I2 = 0%; low certainty), cardiovascular death (13 studies, 1606 participants: RR 1.15, 95% CI 0.45 to 2.98; I2 = 0%; low certainty), kidney failure (3 studies, 837 participants: RR 0.56, 95% CI 0.29 to 1.07; I2 = 0%; low certainty), and doubling of SCr (2 studies, 767 participants: RR 0.88, 95% CI 0.52 to 1.48; I2 = 0%; low certainty). Compared to ACEi plus ARB, ACEi alone has uncertain effects on all-cause death (6 studies, 1166 participants: RR 1.08, 95% CI 0.49 to 2.40; I2 = 20%; low certainty), withdrawal from treatment (2 studies, 172 participants: RR 0.78, 95% CI 0.33 to 1.86; I2 = 0%; low certainty), cardiovascular death (4 studies, 994 participants: RR 3.02, 95% CI 0.61 to 14.85; low certainty), kidney failure (3 studies, 880 participants: RR 1.36, 95% CI 0.79 to 2.32; I2 = 0%; low certainty), and doubling of SCr (2 studies, 813 participants: RR 1.14, 95% CI 0.70 to 1.85; I2 = 0%; low certainty). Compared to ACEi plus ARB, ARB alone has uncertain effects on all-cause death (7 studies, 2607 participants: RR 1.02, 95% CI 0.76 to 1.37; I2 = 0%; low certainty), withdrawn from treatment (3 studies, 1615 participants: RR 0.81, 95% CI 0.53 to 1.24; I2 = 0%; low certainty), cardiovascular death (4 studies, 992 participants: RR 3.03, 95% CI 0.62 to 14.93; low certainty), kidney failure (4 studies, 2321 participants: RR 1.15, 95% CI 0.67 to 1.95; I2 = 29%; low certainty), and doubling of SCr (3 studies, 2252 participants: RR 1.18, 95% CI 0.85 to 1.64; I2 = 0%; low certainty). Comparative effects of different ACEi or ARB and low-dose versus high-dose ARB were rarely evaluated. No study compared different doses of ACEi. Adverse events of ACEi and ARB were rarely reported.

AUTHORS' CONCLUSIONS

ACEi or ARB may make little or no difference to all-cause and cardiovascular death compared to placebo or no treatment in people with diabetes and kidney disease but may prevent kidney failure. ARB may prevent the doubling of SCr and the progression from microalbuminuria to macroalbuminuria compared with a placebo or no treatment. Despite the international guidelines suggesting not combining ACEi and ARB treatment, the effects of ACEi or ARB monotherapy compared to dual therapy have not been adequately assessed. The limited data availability and the low quality of the included studies prevented the assessment of the benefits and harms of ACEi or ARB in people with diabetes and kidney disease. Low and very low certainty evidence indicates that it is possible that further studies might provide different results.

Efficacy of Direct Renin Inhibitors in Slowing Down the Progression of Diabetic Kidney Disease: A Meta-Analysis

Albuminuria is a risk factor for chronic kidney disease and cardiovascular events in diabetic people. The pathogenic processes in these circumstances have been documented to be significantly influenced by enhanced renin-angiotensin system activity. The current meta-analysis was carried out to assess the efficacy of direct renin inhibitors in preventing the progression of diabetic kidney disease. This meta-analysis was conducted as per the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). We searched the relevant medical literature through PubMed, Cochrane library and EMBASE. The primary efficacy outcome was a percentage change in urine albumin-creatinine ratio (UACR) (in mg/g) level. Other primary efficacy outcomes included remission from microalbuminuria to normal albuminuria and progression from microalbuminuria to macroalbuminuria. Four randomized control studies were identified and included in the current meta-analysis involving 9,609 participants. The use of direct renin inhibitors was superior in reducing mean UACR compared to angiotensin receptor blockers and angiotensin-converting enzyme inhibitors. The pooled mean difference in UACR between direct renin inhibitors and the control group was 9.42% (95% CI: -15.70 to -3.15: p-value=0.003). The odds of progression from microalbuminuria to normal albuminuria are 1.26 times higher in patients receiving direct renin inhibitors compared to patients in the control group (OR: 1.26, 95% CI: 1.08-1.46, p-value=0.002). The odds of remission from microalbuminuria to macroalbuminuria were 20% lower in patients receiving direct renin inhibitors compared to patients in the control group (OR: 0.80, 95% CI: 0.69-0.93, p-value=0.003). The use of aliskiren is associated with a significant reduction in UACR, increased remission from microalbuminuria to normal albuminuria and decreased progression from microalbuminuria to macroalbuminuria.

Impact of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers on renal and mortality outcomes in people with Type 2 diabetes and proteinuria

AIM

To assess the impact of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers on renal and mortality outcomes in people with Type 2 diabetes and proteinuria.

METHODS

A literature search up to 6 June 2019 was performed. We included randomized trials of ≥100 participants with Type 2 diabetes and micro- or macroalbuminuria comparing an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker with placebo ± background anti-hypertensives or non-angiotensin-converting enzyme inhibitor or angiotensin receptor blocker-containing anti-hypertensives, which included follow-up of ≥12 months. Endpoints included doubling of serum creatinine, end-stage renal disease, all-cause and cardiovascular mortality and progression and regression of proteinuria. A Hartung-Knapp random-effects model (between-study variance calculated using the Paule-Mandel estimator) producing a risk ratio with 95% confidence interval was employed.

RESULTS

The use of an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker was not associated with a significant reduction in the risk of a doubling in serum creatinine (n = 7 trials, RR = 0.77, 95% CI = 0.50-1.21). Angiotensin-converting enzyme inhibitors or angiotensin receptor blockers reduced the risk of progressing to end-stage renal disease (n = 8, RR = 0.79, 95% CI = 0.75-0.83). No difference in all-cause (n = 11, RR = 0.98, 95% CI = 0.89-1.08) or cardiovascular mortality (n = 6 trials, RR = 1.08, 95% CI = 0.92-1.28), nor the composite outcome of doubling in serum creatinine, end-stage renal disease or mortality (n = 3 trials, RR = 0.87, 95% CI = 0.72-1.06), was observed. Progression of proteinuria was decreased with angiotensin-converting enzyme inhibitor or angiotensin receptor blocker use vs. control (n = 10, RR = 0.49, 95% CI = 0.33-0.74). Regression of proteinuria was not improved with an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker (n = 11, RR = 1.55, 95% CI = 0.93-2.58).

CONCLUSION

Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers may reduce the risk of end-stage renal disease and slow the progression of nephropathy, but they do not appear to decrease all-cause or cardiovascular mortality in people with Type 2 diabetes and proteinuria.

Vascular Complication in Adolescents With Diabetes Mellitus

Diabetes mellitus is becoming more prevalent and even with new advancements which improve glycaemic control, complications of diabetes are common. Vascular complications of diabetes include the microvascular complications: retinopathy, nephropathy, and peripheral and autonomic neuropathy. Macrovascular complications are also common in patients with diabetes and arguably more concerning as they confer a high mortality risk yet are sometimes under-treated. Risk factors for diabetes complications start to occur in childhood and adolescents and some youths may be diagnosed with complications before transition to adult care. This article discusses the prevalence, risk factors, screening, and treatment recommendations for vascular complications in children and adolescents with diabetes.

Vitamin B and its derivatives for diabetic kidney disease

BACKGROUND

Diabetes is a leading cause of end-stage kidney disease (ESKD) mainly due to development and progression of diabetic kidney disease (DKD). In absence of definitive treatments of DKD, small studies showed that vitamin B may help in delaying progression of DKD by inhibiting vascular inflammation and endothelial cell damage. Hence, it could be beneficial as a treatment option for DKD.

OBJECTIVES

To assess the benefits and harms of vitamin B and its derivatives in patients with DKD.

SEARCH METHODS

We searched the Cochrane Renal Group's Specialised Register to 29 October 2012 through contact with the Trials' Search Co-ordinator using search terms relevant to this review.

SELECTION CRITERIA

We included randomised controlled trials comparing vitamin B or its derivatives, or both with placebo, no treatment or active treatment in patients with DKD. We excluded studies comparing vitamin B or its derivatives, or both among patients with pre-existing ESKD.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study eligibility, risk of bias and extracted data. Results were reported as risk ratio (RR) or risk differences (RD) with 95% confidence intervals (CI) for dichotomous outcomes and mean difference (MD) with 95% CI for continuous outcomes. Statistical analyses were performed using the random-effects model.

MAIN RESULTS

Nine studies compared 1354 participants randomised to either vitamin B or its derivatives with placebo or active control were identified. A total of 1102 participants were randomised to single vitamin B derivatives, placebo or active control in eight studies, and 252 participants randomised to multiple vitamin B derivatives or placebo. Monotherapy included different dose of pyridoxamine (four studies), benfotiamine (1), folic acid (1), thiamine (1), and vitamin B12 (1) while combination therapy included folic acid, vitamin B6, and vitamin B12 in one study. Treatment duration ranged from two to 36 months. Selection bias was unclear in three studies and low in the remaining six studies. Two studies reported blinding of patient, caregiver and observer and were at low risk of performance and detection bias, two studies were at high risk bias, and five studies were unclear. Attrition bias was high in one study, unclear in one study and low in seven studies. Reporting bias was high in one study, unclear in one study, and low in the remaining seven studies. Four studies funded by pharmaceutical companies were judged to be at high risk bias, three were at low risk of bias, and two were unclear.Only a single study reported a reduction in albuminuria with thiamine compared to placebo, while second study reported reduction in glomerular filtration rate (GFR) following use of combination therapy. No significant difference in the risk of all-cause mortality with pyridoxamine or combination therapy was reported. None of the vitamin B derivatives used either alone or in combination improved kidney function: increased in creatinine clearance, improved the GFR; neither were effective in controlling blood pressure significantly compared to placebo or active control. One study reported a significant median reduction in urinary albumin excretion with thiamine treatment compared to placebo. No significant difference was found between vitamin B combination therapy and control group for serious adverse events, or one or more adverse event per patient. Vitamin B therapy was reported to well-tolerated with mild side effects in studies with treatment duration of more than six months. Studies of less than six months duration did not explicitly report adverse events; they reported that the drugs were well-tolerated without any serious drug related adverse events. None of the included studies reported cardiovascular death, progression from macroalbuminuria to ESKD, progression from microalbuminuria to macroalbuminuria, regression from microalbuminuria to normoalbuminuria, doubling of SCr, and quality of life. We were not able to perform subgroup or sensitivity analyses or assess publication bias due to insufficient data.

AUTHORS' CONCLUSIONS

There is an absence of evidence to recommend the use of vitamin B therapy alone or combination for delaying progression of DKD. Thiamine was found to be beneficial for reduction in albuminuria in a single study; however, there was lack of any improvement in kidney function or blood pressure following the use of vitamin B preparations used alone or in combination. These findings require further confirmation given the limitations of the small number and poor quality of the available studies.

Diabetic kidney lesions of GIPRdn transgenic mice: podocyte hypertrophy and thickening of the GBM precede glomerular hypertrophy and glomerulosclerosis

Diabetic nephropathy is the leading cause of end-stage renal disease and the largest contributor to the total cost of diabetes care. Rodent models are excellent tools to gain more insight into the pathogenesis of diabetic nephropathy. In the present study, we characterize the age-related sequence of diabetes-associated kidney lesions in GIPRdn transgenic mice, a novel mouse model of early-onset diabetes mellitus. Clinical-chemical analyses as well as qualitative and quantitative morphological analyses of the kidneys of GIPRdn transgenic animals and nontransgenic littermate controls were performed at 3, 8, 20, and 28 wk of age. Early renal changes of transgenic mice consisted of podocyte hypertrophy, reduced numerical volume density of podocytes in glomeruli, and homogenous thickening of the glomerular basement membrane, followed by renal and glomerular hypertrophy as well as mesangial expansion and matrix accumulation. At 28 wk of age, glomerular damage was most prominent, including advanced glomerulosclerosis, tubulointerstitial lesions, and proteinuria. Real-time PCR demonstrated increased glomerular expression of Col4a1, Fn1, and Tgfb1. Immunohistochemistry revealed increased mesangial deposition of collagen type IV, fibronectin, and laminin. The present study shows that GIPRdn transgenic mice exhibit renal changes that closely resemble diabetes-associated kidney alterations in humans. Data particularly from male transgenic mice indicate that podocyte hypertrophy is directly linked to hyperglycemia, without the influence of mechanical stress. GIPRdn transgenic mice are considered an excellent new tool to study the mechanisms involved in onset and progression of diabetic nephropathy.

Microalbuminuria screening in patients with hypertension: recommendations for clinical practice

INTRODUCTION

Correlations between renal and cardiovascular (CV) pathologies in advanced kidney or heart disease are well characterised, but less clearly defined in the early stages. Microalbuminuria, in addition to being an early sign of kidney damage, is often found in patients with essential hypertension, suggesting that it may reflect early vascular abnormalities.

EVIDENCE FROM LITERATURE

Studies have shown that even very low levels of microalbuminuria strongly correlate with CV risk: albumin excretion rates as low as 4.8 microg/min, well below the microalbuminuria thresholds stated in current clinical guidelines, are associated with increased risk of CV and cerebrovascular disease, independent of the presence of other risk factors. Increased microalbuminuria indicates endothelial dysfunction or developing atherosclerosis and predicts end-organ damage, major cardio or cerebrovascular events and death.

CLINICAL ASPECTS

Available tests for screening microalbuminuria are sensitive, reliable and accessible; current European and US guidelines advocate annual screening in patients with diabetes and wherever possible in non-diabetic patients with hypertension. Early identification of high-risk patients through detection of microalbuminuria allows selection of aggressive treatment to slow disease progression.

THERAPEUTIC IMPLICATIONS

Antihypertensive agents providing angiotensin II blockade are recommended for the treatment of hypertensive patients with microalbuminuria, regardless of diabetes and/or early or overt nephropathy. Treatment with angiotensin II receptor blockers provides effective reduction of microalbuminuria and blood pressure, and long-term prevention of CV events beyond blood pressure reduction. In addition, pharmacoeconomic studies have shown that these long-term benefits translate into a substantially reduced burden on healthcare resources.

Identifying children at particular risk of long-term diabetes complications

Formerly a 'taboo' subject, long-term complications are now being increasingly discussed with the family by the health-care team. Identifying potential predictors and establishing early intervention can change the course of these complications in the young patient with diabetes. Although the most recognized risk factor is glycaemic exposure, the development of diabetes complications is likely to result from an interaction between genetic and environmental factors. Other major environmental risk factors are hypertension, smoking, higher body mass index and lipid disorders. This article will concentrate on specific paediatric aspects, including the impact of puberty; endothelial dysfunction and genetic susceptibility. Endothelial function assessed by flow-mediated dilatation is a non-invasive method that has been suitable for use in children and adolescents. In type 1 diabetes mellitus children, endothelium dysfunction has been documented among patients with short diabetes duration and has been correlated to folate status, triglyceride and low-density lipoprotein cholesterol levels. Studies in the paediatric population have also revealed an association of diabetes complications with genetic variants in the renin-angiotensin system, polyol pathway, lipid oxidation and folate metabolism. Currently, achieving the best glycaemic control remains the gold standard for prevention of long-term diabetes complications in the clinical context. However, recent identification of genetic markers and development of research tools that predict long-term complications might have a potential role as instruments in assessing the effectiveness of intervention in the early course of the disease.

Antihypertensive Therapy in the Presence of Proteinuria

The presence of proteinuria is a well-known risk factor for both the progression of renal disease and cardiovascular morbidity and mortality, and decreases in urine protein excretion level were associated with a slower decrease in renal function and decrease in risk of cardiovascular events. Increased blood pressure has a major role in the development of proteinuria in patients with either diabetic or nondiabetic kidney disease, and all recent guidelines recommend a blood pressure goal less than 130/80 mm Hg in patients with proteinuria to achieve maximal renal and cardiovascular protection. Drugs interfering with the renin-angiotensin system, ie, angiotensin-converting enzyme inhibitors and angiotensin receptor blockers, should be used as first-line antihypertensive therapy in patients with proteinuria because they seem to have a blood pressure-independent antiproteinuric effect, and if blood pressure levels are still out of goal, a diuretic should be added to this regimen. A combination of an angiotensin-converting enzyme inhibitor with an angiotensin receptor blocker or other classes of medications shown to decrease protein excretion, such as nondihydropyridine calcium antagonists or aldosterone receptor blockers, should be considered to decrease proteinuria further. This review provides an extended summary of current evidence regarding the associations of blood pressure with proteinuria, the rationale for currently recommended blood pressure goals, and the use of various classes of antihypertensive agents in proteinuric patients.

Angiotensin converting enzyme inhibitors and angiotensin II receptor antagonists for preventing the progression of diabetic kidney disease

BACKGROUND

Angiotensin converting enzyme inhibitors (ACEi) and angiotensin II receptor antagonists (AIIRA) are considered to be equally effective for patients with diabetic kidney disease (DKD), but renal and not mortality outcomes have usually been considered.

OBJECTIVES

To evaluate the benefits and harms ACEi and AIIRA in patients with DKD.

SEARCH STRATEGY

We searched MEDLINE (1966 to December 2005), EMBASE (1980 to December 2005), the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library issue 4 2005) and contacted known investigators.

SELECTION CRITERIA

Studies comparing ACEi or AIIRA with placebo or each other in patients with DKD were included.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. Statistical analyses were performed using the random effects model and results expressed as relative risk (RR) with 95% confidence intervals (CI). Heterogeneity among studies was explored using the Cochran Q statistic and the I(2) test, subgroup analyses and random effects metaregression.

MAIN RESULTS

Fifty studies (13,215 patients) were identified. Thirty eight compared ACEi with placebo, five compared AIIRA with placebo and seven compared ACEi and AIIRA directly. There was no significant difference in the risk of all-cause mortality for ACEi versus placebo (RR 0.91, 95% CI 0.71 to 1.17) and AIIRA versus placebo (RR 0.99, 95% CI 0.85 to 1.17). A subgroup analysis of studies using full-dose ACEi versus studies using half or less than half the maximum tolerable dose of ACEi showed a significant reduction in the risk of all-cause mortality with the use of full-dose ACEi (RR 0.78, 95% CI 0.61 to 0.98). Baseline mortality rates were similar in the ACEi and AIIRA studies. The effects of ACEi and AIIRA on renal outcomes (ESKD, doubling of creatinine, prevention of progression of micro- to macroalbuminuria, remission of micro- to normoalbuminuria) were similarly beneficial. Reliable estimates of effect of ACEi versus AIIRA could not be obtained from the three studies in which they were compared directly because of their small sample size.

AUTHORS' CONCLUSIONS

Although the survival benefits of ACEi are known for patients with DKD, the relative effects on survival of ACEi with AIIRA are unknown due to the lack of adequate direct comparison studies. In placebo controlled studies, only ACEi (at the maximum tolerable dose, but not lower so-called renal doses) were found to significantly reduce the risk of all-cause mortality. Renal and toxicity profiles of these two classes of agents were not significantly different.

Role of Blood Pressure Targets and Specific Antihypertensive Agents Used to Prevent Diabetic Nephropathy and Delay Its Progression: Table 1

This study evaluated the comparative effects of antihypertensive agents in patients with diabetes and normoalbuminuria and the evidence supporting equivalent use of angiotensin-converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARB) in patients with diabetes and micro- or macroalbuminuria. A systematic review was conducted by searching for randomized controlled trials (RCT) of antihypertensive agent versus placebo or another agent in hypertensive or normotensive patients with diabetes and no nephropathy and RCT of ACEi or ARB in patients with diabetic nephropathy. Medline, Embase, the Cochrane Controlled Trials Register, conference proceedings, and contact with investigators were used to identify available evidence. Two investigators independently extracted data and assessed quality of trials. Sixteen RCT (7603 patients) of antihypertensive agents conducted in patients with diabetes and no nephropathy and 43 (7739 patients) of ACEi or ARB in patients with diabetic nephropathy were identified. A significant reduction in the risk for developing microalbuminuria in patients who had diabetes with no nephropathy was demonstrated for ACEi only (six trials, 3840 patients; relative risk [RR] 0.60; 95% confidence interval [CI] 0.43 to 0.84), and in patients with diabetic nephropathy, existing RCT have shown a survival benefit of ACEi (20 trials, 2383 patients; RR 0.79; 95% CI 0.63 to 0.99; P = 0.04) but not ARB (four trials, 3329 patients; RR 0.99; 95% CI 0.85 to 1.17). On the basis of available RCT evidence, ACEi are the only agents with proven renal benefit in patients who have diabetes with no nephropathy and the only agents with proven survival benefit in patients who have diabetes with nephropathy.

Validation of a human immunoturbidimetric assay to measure canine albumin in urine and cerebrospinal fluid

The aim of this study was to validate an automated immunoturbidimetric assay used to quantify human albumin in urine and to accurately measure canine albumin concentrations in both urine and cerebrospinal fluid. The partial homology existing between human and canine albumin limited the accuracy of the human assays in measuring canine albumin without method modifications. Thus, the assay was modified by calibrating the analyzer with calibrators made in the laboratory containing known concentrations of canine albumin. To prepare the set of calibrators, the albumin concentration of pooled sera of healthy dogs was assessed in 5 replicates using the BromocresolGreen assay. Pooled samples were aliquoted and serially diluted to obtain the expected concentrations of albumin (0.5, 1, 5, 13, and 30 mg/dl) for establishing the canine calibration curve. Thereafter, the performance was assessed by analyzing canine urine and CSF The modified assay accurately quantified canine albumin in both specimens, as indicated by the following. Intra- and interassay variability was 0.92% and 2.74%, respectively; recovery was 99.66% and 99.07% in urine and 105.02% in CSF No interference was detected when hemolysate and glucose were added to urine. The test was linear within the verified range (0-225 mg/dl). These results demonstrate that the modified human albumin immunoturbidimetric assay can be a useful tool in the veterinary diagnostic laboratory. It is accurate and tends itself to automatization on chemistry analyzers.

Effects of angiotensin converting enzyme inhibitors and angiotensin II receptor antagonists on mortality and renal outcomes in diabetic nephropathy: systematic review

OBJECTIVE

To evaluate the effects of angiotensin converting enzyme (ACE) inhibitors and angiotensin II receptor antagonists (AIIRAs) on renal outcomes and all cause mortality in patients with diabetic nephropathy.

DATA SOURCES

Medline, Embase, the Cochrane controlled trials register, conference proceedings, and contact with investigators.

STUDY SELECTION

Trials comparing ACE inhibitors or AIIRAs with placebo or with each other in patients with diabetic nephropathy.

DATA EXTRACTION

Mortality, renal outcomes (end stage renal disease, doubling of serum creatinine concentration, prevention of progression of microalbuminuria to macroalbuminuria, remission of microalbuminuria), and quality of trials.

DATA SYNTHESIS

36 of 43 identified trials compared ACE inhibitors with placebo (4008 patients), four compared AIIRAs with placebo (3331 patients), and three compared ACE inhibitors with AIIRAs (206 patients). We obtained unpublished data for 11 trials. ACE inhibitors significantly reduced all cause mortality (relative risk 0.79, 95% confidence interval 0.63 to 0.99) compared with placebo but AIIRAs did not (0.99, 0.85 to 1.17), although baseline mortality was similar in the trials. Both agents had similar effects on renal outcomes. Reliable estimates of the unconfounded relative effects of ACE inhibitors compared with AIIRAs could not be obtained owing to small sample sizes.

CONCLUSION

Although the survival benefits of ACE inhibitors for patients with diabetic nephropathy are known, the relative effects of ACE inhibitors and AIIRAs on survival are unknown owing to the lack of adequate head to head trials.

The short-term effect of a switch from glibenclamide to metformin on blood pressure and microalbuminuria in patients with type 2 diabetes mellitus

BACKGROUND

Renal hyperfiltration and albuminuria have a deleterious effect on kidney function. Therefore, we studied the effect of metformin on blood pressure, renal hemodynamics, and microalbuminuria in type 2 diabetic patients.

METHODS

A clinical trial was designed in type 2 diabetic patients with incipient nephropathy. All patients were below the age of 65, normotensive, and without evidence of malignant, hepatic, or cardiovascular disorders. They were randomly allocated to receive glibenclamide or metformin. At baseline and 12 weeks thereafter we measured body mass index (BMI), serum insulin, blood glucose, lipid profile, glycosylated hemoglobin, blood pressure, glomerular filtration rate, renal plasma flow, and urine albumin.

RESULTS

We studied 23 patients in the glibenclamide group and 28 in the metformin group. There was no difference in baseline variables between the groups. Metabolic control was obtained in both groups. In the metformin group, all the following variables decreased: microalbuminuria was reduced by a mean of 24.2 mg/day (p = 0.008); systolic and diastolic blood pressure by a mean of 5.3 mmHg (p = 0.002) and 3.93 mmHg (p = 0.009), respectively; insulin levels by an average of 11.8 microIU/mL (p = 0.001), and total cholesterol levels and triglycerides by an average of 0.45 and 0.18 mmol/L, respectively. Insulin resistance measured by the homeostasis model decreased more in the metformin group than in the glibenclamide group. Patients treated with glibenclamide had an increase in HDL cholesterol of 0.082 mmol/L (p = 0.01).

CONCLUSIONS

Metformin significantly decreased the urine albumin excretion rate with none of the expected changes in renal hemodynamics, probably due to its favorable effects on blood pressure, lipid profile, metabolic control, and insulin resistance.

Diabetic nephropathy

Diabetic nephropathy remains a leading cause of end-stage renal disease (ESRD) in western societies, accounting for over one-third of all patients beginning renal replacement therapy. Patients with Type 2 diabetes comprise the largest and fastest-growing single disease group requiring renal support therapy. In addition to the high risk of progression to ESRD, diabetic nephropathy is associated with a very high risk of cardiovascular morbidity and mortality, which is not abolished by dialysis and renal transplantation. While the prognosis of patients with diabetic nephropathy has considerably improved, a greater focus has recently been placed on treating diabetic patients early in order to prevent future organ failure. Microalbuminuria is an important intermediary end-point that correlates strongly with future advanced renal disease and cardiovascular mortality. Recent evidence indicates that optimum glycaemic control, tight blood pressure control, and the regular screening for and early treatment of microalbuminuria are necessary to prevent the development and progression of diabetic renal disease. By utilizing such strategies, the challenge is to reduce the cumulative incidence of overt nephropathy, with its associated increase in cardiovascular mortality, and the requirement for renal support therapy. Over the next 5-10 years, the patient with Type 2 diabetes will need to be the specific focus of such preventive treatment modalities.