Effects of long-term enalapril treatment on persistent micro-albuminuria in well-controlled hypertensive and normotensive NIDDM 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.

Phase 1 Studies to Define the Safety, Tolerability, and Pharmacokinetic and Pharmacodynamic Profiles of the Nonsteroidal Mineralocorticoid Receptor Antagonist Apararenone in Healthy Volunteers

Apararenone is a long-acting, nonsteroidal mineralocorticoid receptor antagonist (MRA). The safety, tolerability, and pharmacokinetic (PK) and pharmacodynamic (PD) profiles of single- and multiple-dose apararenone were assessed in 3 phase 1 randomized, double-blind studies in 223 healthy adults. Study 1 assessed the PK, safety/tolerability, and PD of single-dose apararenone (3.75-640 mg) and multiple-dose apararenone (10-40 mg/day on days 1-14, 320 mg loading dose on day 1 + 10 mg/day on days 2-14, or 40-320 mg loading dose on day 1 + 2.5-20 mg/day on days 2-14) in Caucasian and Black men and women. Study 2 assessed the PK and safety of single-dose apararenone (5-320 mg) in healthy Japanese men. Study 3 assessed the PK, PD, and safety/tolerability of single-dose apararenone (160 or 640 mg) or eplerenone (200 mg; only for 160 mg of apararenone), each after fludrocortisone challenge in Caucasian men. In studies 1 and 2, an approximately dose-proportional increase was observed in PK parameters over the apararenone dose range of 3.75-40 mg; at higher doses, a less than dose-proportional increase was observed. Food, sex, age, and race had no apparent effect on apararenone PK. A long half-life was seen for apararenone and its principal metabolite; in addition, the exposure of the metabolite was lower than that of apararenone. Apararenone suppressed the decrease in urinary sodium and potassium ion ratio that occurs after loading with fludrocortisone. These studies support the mechanism of action of apararenone as an MRA, and further clinical development is warranted.

Apararenone in patients with diabetic nephropathy: results of a randomized, double-blind, placebo-controlled phase 2 dose-response study and open-label extension study

Background

We investigated the efficacy and safety of apararenone (MT-3995), a non-steroidal compound with mineralocorticoid receptor agonist activity, in patients with stage 2 diabetic nephropathy (DN).

Methods

The study had two parts: a dose–response, parallel-group, randomized, double-blind, placebo-controlled, multicenter, phase 2, 24-week study and an open-label, uncontrolled, 28-week extension study. Primary and secondary endpoints were the 24-week percent change from baseline in urine albumin to creatine ratio (UACR) and 24- and 52-week UACR remission rates. Safety parameters were changes from baseline in estimated glomerular filtration rate (eGFR) and serum potassium at 24 and 52 weeks, and incidences of adverse events (AEs) and adverse drug reactions (ADRs).

Results

In the dose–response period, 73 patients received placebo and 73, 74, and 73 received apararenone 2.5 mg, 5 mg, and 10 mg, respectively. As a percentage of baseline, mean UACR decreased to 62.9%, 50.8%, and 46.5% in the 2.5 mg, 5 mg, and 10 mg apararenone groups, respectively, at week 24 (placebo: 113.7% at week 24; all P < 0.001 vs placebo). UACR remission rates at week 24 were 0.0%, 7.8%, 29.0%, and 28.1% in the placebo and apararenone 2.5 mg, 5 mg, and 10 mg groups, respectively. eGFR tended to decrease and serum potassium tended to increase, but these events were not clinically significant. AE incidence increased with dose while ADR incidence did not.

Conclusion

The UACR-lowering effect of apararenone administered once daily for 24 weeks in patients with stage 2 DN was confirmed, and the 52-week administration was safe and tolerable.

Clinical trial registration

NCT02517320 (dose–response study) and NCT02676401 (extension study)

Electronic supplementary material

The online version of this article (10.1007/s10157-020-01963-z) contains supplementary material, which is available to authorized users.

Effect of ACE-inhibition on coronary microvascular function and symptoms in normotensive women with microvascular angina: A randomized placebo-controlled trial

Objective

Studies have suggested a beneficial effect of angiotensin-converting enzyme (ACE) inhibition. To explore whether the ACE inhibitor ramipril has a direct effect on the microvasculature beyond the blood pressure (BP) lowering effect, we investigated whether ramipril improved coronary microvascular function in normotensive women with coronary microvascular dysfunction (CMD).

Methods

We included 63 normotensive women with angina, no epicardial stenosis>50% and CMD defined as a coronary flow velocity reserve (CFVR)<2.2 assessed by adenosine stress-echocardiography in a randomized double-blinded, superiority trial with 1:1 allocation to placebo or ramipril (maximum dose 10 mg depending on blood pressure) for 24±6 weeks. Primary outcome was CFVR. Secondary outcomes were left ventricular systolic and diastolic function and symptoms evaluated by Seattle Angina Questionnaire (clinicaltrials.gov, NCT02525081).

Results

Follow-up was available on 55 patients. BP remained unchanged during treatment in both groups. CFVR improved in both the ramipril (p = 0.004) and placebo group (p = 0.026) with no difference between groups (p = 0.63). Symptoms improved in both groups with no significant between-group differences. No changes were detected in parameters of systolic and diastolic function. No serious adverse reactions were reported.

Conclusions

In normotensive women with angina and CMD, treatment with ramipril had no significant effect on CFVR or symptoms compared with placebo. The effect of ACE inhibition previously reported may be mediated by blood pressure reduction.

Comparative Efficacy and Safety of Antihypertensive Agents for Adult Diabetic Patients with Microalbuminuric Kidney Disease: A Network Meta-Analysis

BACKGROUND

Antihypertensive treatment mitigates the progression of chronic kidney disease. Here, we comparatively assessed the effects of antihypertensive agents in normotensive and hypertensive diabetic patients with microalbuminuric kidney disease.

METHODS

MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials were systematically searched for randomized controlled trials (RCTs) comparing oral antihypertensive agents in adult diabetic patients with microalbuminuria. The primary efficacy outcome was reduction in albuminuria, and the primary safety outcomes were dry cough, presyncope, and edema. Random-effects pairwise and Bayesian network meta-analyses were performed to produce outcome estimates for all RCTs, only hypertensive RCTs, or only normotensive RCTs. Surface under the cumulative ranking (SUCRA) probability rankings were calculated for all outcomes. Sensitivity analyses on type 2 diabetes status, age, or follow-up duration were also performed.

RESULTS

A total of 38 RCTs were included in the meta-analyses. The angiotensin-converting enzyme inhibitor-calcium channel blocker (ACEI-CCB) combination therapy of captopril+diltiazem was most efficacious in reducing albuminuria irrespective of blood pressure status. However, the ACEI-angiotensin receptor blocker (ACEI-ARB) combination therapy of trandolapril+candesartan was the most efficacious in reducing albuminuria for normotensive patients, while the ACEI-CCB combination therapy of fosinopril+amlodipine was the most efficacious in reducing albuminuria for hypertensive patients. The foregoing combination therapies displayed inferior safety profiles relative to ACEI monotherapy with respect to dry cough, presyncope, and edema. With respect to type 2 diabetic patients with microalbuminuria, the Chinese herbal medicine Tangshen formula followed by the ACEI ramipril were the most efficacious in reducing albuminuria.

CONCLUSIONS

Trandolapril+candesartan appears to be the most efficacious intervention for reducing albuminuria for normotensive patients, while fosinopril+amlodipine appears to be the most efficacious intervention for reducing albuminuria for hypertensive patients. For practitioners opting for monotherapy, our SUCRA analysis supports the use of trandolapril and fosinopril in normotensive and hypertensive adult diabetic patients with microalbuminuria, respectively.

Assessment of renal dysfunction with diffusion-weighted imaging: comparing intra-voxel incoherent motion (IVIM) with a mono-exponential model

BACKGROUND

Because renal dysfunction is a worldwide problem, accurate assessment is required for planning treatment and follow-up. Intra-voxel incoherent motion (IVIM) can isolate fast from slow water motion in well-perfused organs and may be helpful in assessing renal dysfunction.

PURPOSE

To determine the clinical value of IVIM in the assessment of renal dysfunction compared with a mono-exponential model.

MATERIAL AND METHODS

Fifty-four consecutive participants (mean age, 53.13 ± 13.96 years) were recruited into this study. The estimated glomerular filtration rate (eGFR) was calculated to classify the participants as having severe renal injury (sRI, eGFR ≤ 30 mL/min/1.73 m(2)) or not (non-sRI). DWI with seven b-factors was performed. Image analysis was performed by a radiologist to generate an apparent diffusion coefficient map (ADCmon) by mono-exponential model, diffusion coefficient (Dslow and Dfast), and fraction of fast diffusion (Ffast) maps by IVIM. The circular regions of interest were placed at the interface between the cortex and medulla for parameter measurements.

RESULTS

The ADCmon, Dslow, Dfast, and Ffast were less in sRI than non-sRI (P < 0.05). ADCmon and Dslow were positively related with eGFR (P < 0.05). For differentiating sRI from non-sRI, receiver operating characteristic curve indicated no significant difference between the two methods (P > 0.05). Furthermore, the correlation was 0.93 between ADCmon and Dslow, followed by 0.57 between Dfast and Ffast, 0.48 between ADCmon and Dfast, and 0.34 between ADCmon and Ffast (P < 0.05).

CONCLUSION

The IVIM model contributed little to improving the assessment of renal dysfunction compared with a mono-exponential model.

Is low b-factors-based apparent diffusion coefficient helpful in assessing renal dysfunction?

PURPOSE

To investigate whether low b-factors-based apparent diffusion coefficient (ADC) is helpful in assessing renal dysfunction.

MATERIALS AND METHODS

Forty-four subjects were recruited, and classified as having severe renal injury group (sRI) or not (non-sRI) according to a threshold of estimated glomerular filtration rate (eGFR) = 30 ml/min/1.73 m(2). A free-breathing DWI with 7 b-factors (0, 20, 40, 80, 200, 400, and 800 s/mm(2)) was performed. After choosing an anatomical section that covered the largest part of right kidney, the regions of interest covered the renal parenchyma. For each subject, two apparent diffusion coefficients based on all b-factors less than 400 s/mm(2) (ADC0-400) and 800 s/mm(2) (ADC0-800) were calculated by fitting the signal intensity at different b-factors to a mono-exponential decay, respectively. It was found that the examination time of the free-breathing DWI sequence in this study can be reduced from 3.27 to 2.55 min if the b-factor (800 s/mm(2)) is removed.

RESULTS

ADC0-400 was larger than ADC0-800 in each group (P < 0.05). Both ADC0-400 and ADC0-800 were smaller in the sRI group than those in the non-sRI group (P < 0.01), and they were linearly related with eGFR (P < 0.05). While a significant difference was not found between the two coefficients to differentiate sRI from non-sRI participants (P > 0.05), a strong correlation was present between ADC0-400 and ADC0-800 (r = 0.856, P < 0.001).

CONCLUSION

The low b-factors-based ADC was an economical option for reducing the examination time without sacrificing its diagnostic performance.

Therapeutic approaches to slowing the progression of diabetic nephropathy - is less best?

OBJECTIVE

Angiotensin II receptor blockers (ARBs) and angiotensin-converting enzyme (ACE) inhibitors are known to reduce proteinuria and have been the first-line agents in the management of diabetic nephropathy for the past 20 years. This review covers recent studies that compare the benefit of additional blockage of the renin-angiotensin-aldosterone system through combination therapy with an ACE inhibitor and ARB, or a direct renin inhibitor (DRI), to monotherapy.

DESIGN

Primary and review articles that addressed the pathophysiology, diagnosis, and therapeutic options for attenuating the progression of diabetic nephropathy were retrieved through a MEDLINE search (January 1990 to December 2012) and the bibliographies of identified articles were reviewed. English language sources were searched using the following search terms: diabetes mellitus, nephropathy, proteinuria, ACE inhibitors, ARBs, and DRIs.

SETTING

Randomized, placebo-controlled, short- and long-term studies published in peer-reviewed journals that were determined to be methodologically sound, with appropriate statistical analysis of the results, were selected for inclusion in this review.

PARTICIPANTS

Adult (≥18 years) patients with diabetic nephropathy.

MEASUREMENTS

Serum creatinine level was used to estimate glomerular filtration rate (GFR). GFR was calculated using the four-variable Modification of Diet in Renal Disease formula. The urine albumin-to-creatinine ratio was measured at baseline and at the conclusion of each study. A value between 3.4 mg/mmol and below 33.9 mg/mmol was defined as microalbuminuria. A value of 33.9 mg/mmol or more (approximately 300 mg/g creatinine) was defined as macroalbuminuria.

RESULTS

ACE inhibitors and ARBs are now the mainstay of treatment for diabetic nephropathy. However, combination therapy with an ACE inhibitor and an ARB, or DRI, has not been found to be more effective than monotherapy with an ACE inhibitor or ARB, and may increase the risk of hyperkalemia or acute kidney injury.

CONCLUSION

Both ACE inhibitors and ARBs remain the first-line agents in attenuating the progression of diabetic nephropathy; however, recent studies suggest that combining an ACE inhibitor with an ARB, or combining a DRI with an ACE inhibitor or ARB, may increase adverse events without clinical benefits to offset them.

Urinary N-acetyl-β-D-glucosaminidase levels are positively correlated with 2-hr plasma glucose levels during oral glucose tolerance testing in prediabetes

BACKGROUND

Urinary N-acetyl-β-D-glucosaminidase (NAG) excretion is increased in patients with impaired glucose tolerance (IGT). This study investigated when during the oral glucose tolerance test (OGTT) the plasma glucose, urine glucose, and insulin levels correlate most strongly with urinary N-acetyl-β-d-glucosaminidase (NAG) levels in prediabetic subjects.

METHODS

The OGTT was administered to 80 subjects who had not yet received a diagnosis of diabetes mellitus (DM) and in whom HbA1c levels were ≤6.8% and fasting plasma glucose levels were <7.0 mmol/l. Forty-two subjects had normal glucose tolerance (NGT), 31 had impaired glucose tolerance (IGT), and 7 had DM according to World Health Organization criteria. Serum levels of cystatin C, the estimated glomerular filtration rate, the urinary albumin-to-creatinine (Cr) ratio, urinary and serum β2-microglobulin, and urinary NAG were measured as markers of renal function.

RESULTS

NAG levels were significantly higher in subjects with DM and in subjects with IGT than in subjects with NGT. No significant associations were observed between glycemic status and other markers of renal function. Multiple linear regression analysis showed that the NAG level was positively correlated with plasma glucose levels at 120 min of the OGTT and was associated with the glycemic status of prediabetic patients.

CONCLUSION

These results suggest that postprandial hyperglycemia is an independent factor that causes renal tubular damage in prediabetes patients.

Angiotensin-converting enzyme inhibitors, angiotensin receptor blockers and combined therapy in patients with micro- and macroalbuminuria and other cardiovascular risk factors: a systematic review of randomized controlled trials

BACKGROUND

A recent clinical trial showed harmful renal effects with the combined use of angiotensin-converting enzyme inhibitors (ACEI) and angiotensin-II receptor blockers (ARB) in people with diabetes or vascular disease. We examined the benefits and risks of these agents in people with albuminuria and one or more cardiovascular risk factors.

METHODS

MEDLINE, EMBASE and Renal Health Library were searched for trials comparing ACEI, ARB or their combination with placebo or with one another in people with albuminuria and one or more cardiovascular risk factor.

RESULTS

Eighty-five trials (21,708 patients) were included. There was no significant reduction in the risk of all-cause mortality or fatal cardiac-cerebrovascular outcomes with ACEI versus placebo, ARB versus placebo, ACEI versus ARB or with combined therapy with ACEI + ARB versus monotherapy. There was a significant reduction in the risk of nonfatal cardiovascular events with ACEI versus placebo but not with ARB versus placebo, ACEI versus ARB or with combined therapy with ACEI + ARB versus monotherapy. Development of end-stage kidney disease and progression of microalbuminuria to macroalbuminuria were reduced significantly with ACEI versus placebo and ARB versus placebo but not with combined therapy with ACEI + ARB versus monotherapy.

CONCLUSIONS

ACEI and ARB exert independent renal and nonfatal cardiovascular benefits while their effects on mortality and fatal cardiovascular disease are uncertain. There is a lack of evidence to support the use of combination therapy. A comparative clinical trial with ACE, ARB and its combination in people with albuminuria and a cardiovascular risk factor is warranted.

The importance of renin-angiotensin blockade in patients with cardio-renal disease

The existence of the renin-angiotensin-aldosterone system was first postulated over 100 years ago. Following the identification of all the major components, came the discovery of their potential pathogenicity in cardiovascular and renal disease. The introduction of drugs that inhibit the synthesis or actions of this system has prompted a number of trials that have largely shaped how cardiovascular and renal disease is managed today. The continued discovery of yet more components of this system promises to further our understanding of its influence on disease processes and herald the development of more highly selective drugs, ensuring that the renin-angiotensin-aldosterone system will continue to be a key area of interest for many years to come.

Evidence-based approach for managing hypertension in type 2 diabetes

Blood pressure (BP) control is a critical part of managing patients with type 2 diabetes. Perhaps it is the single most important aspect of diabetes care, which unlike hyperglycemia and dyslipidemia can reduce both micro- and macrovascular complications. Hypertension is more prevalent in individuals with diabetes than general population, and in most cases its treatment requires two or more pharmacological agents (about 30% of individuals with diabetes need 3 or more medications to control BP). In this article we describe the key evidence that has contributed to our understanding that reduced BP translates into positive micro- and macrovascular outcomes. We review the data supporting current recommendation for BP target < 130/80 mmHg. Two studies suggest that a lower BP goal could be even more beneficial. We also present the comparative benefits of various antihypertensive drugs in reducing diabetes-related micro- and macrovascular complications. Finally we propose an evidence-based algorithm of how to initiate and titrate antihypertensive pharmacotherapy in affected individuals. Overall, achieving BP < 130/80 mmHg is more important than searching for the “best” antihypertensive agent in patients with diabetes.

Effects of renin-angiotensin system blockers on renal outcomes and all-cause mortality in patients with diabetic nephropathy: an updated meta-analysis

BACKGROUND

In contrast to previous studies, recent data questioned the ability of renin-angiotensin-aldosterone system (RAAS) blockers to delay progression of diabetic nephropathy. This study evaluated the effect of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin-receptor blockers (ARBs) in patients with diabetic nephropathy.

METHODS

A systematic literature search of MEDLINE/PubMed and EMBASE databases was performed to identify randomized trials published up to June 2007 comparing the effects of ACEIs or ARBs with placebo and/or a regimen not including a RAAS blocker on the incidence of end-stage renal disease (ESRD), doubling of serum creatinine (DSC), or death from any cause in patients with diabetic nephropathy. Treatment effects were summarized as relative risks (RRs) using the Mantel-Haenszel fixed-effects model.

RESULTS

Of the 1,028 originally identified studies, 24 fulfilled the inclusion criteria (20 using ACEIs and 4 using ARBs). Use of ACEIs was associated with a trend toward reduction of ESRD incidence (RR 0.70; 95% confidence interval (CI) 0.46-1.05) and use of ARBs with significant reduction of ESRD risk (RR 0.78; 95% CI 0.67-0.91). Both drug classes were associated with reduction in the risk of DSC (RR 0.71; 95% CI 0.56-0.91 for ACEIs and RR 0.79; 95% CI 0.68-0.91 for ARBs) but none affected all-cause mortality (RR 0.96; 95% CI 0.85-1.09 for ACEIs and RR 0.99; 95% CI 0.85-1.16 for ARBs).

CONCLUSION

Treatment of patients with diabetic nephropathy with a RAAS blocker reduces the risks of ESRD and DSC, but does not affect all-cause mortality. These findings are added to the evidence of a renoprotective role of RAAS blockers in such patients.

A cost-effectiveness analysis of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers in diabetic nephropathy

The aim of this study was to estimate the cost-effectiveness of renin-angiotensin-aldosterone system blockers in patients with diabetic nephropathy. A cost-effectiveness analysis was performed based on a meta-analysis of studies investigating the effect of angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) as part of a treatment regimen on the incidence of end-stage renal disease (ESRD) in patients with diabetic nephropathy. The primary outcome was the cost to prevent 1 patient from developing ESRD. Cost analysis was performed from a third-party payer perspective in 2006 US dollars. As part of a treatment regimen, ARBs significantly reduced the incidence of ESRD and doubling of serum creatinine concentration (P<.05) but not total mortality. The cost to prevent 1 patient from developing ESRD was $31,729 (95% confidence interval, $19,443-$85,442; P<.01), $189,190 (P=.13) and $51,585 (P=.068) for patients receiving ARBs, ACE inhibitors, or either of them, respectively. This study demonstrates that blocking the RAAS, which delays the progression to ESRD, appears to be cost-effective. The current analysis favors ARBs in terms of cost-effectiveness.

Lowering of proteinuria in response to antihypertensive therapy predicts improved renal function in late but not in early diabetic nephropathy: a pooled analysis

In late diabetic nephropathy (DN) the initial lowering of albumin excretion rate (AER) with antihypertensive therapy is proportional to the degree of subsequent preservation of glomerular filtration rate (GFR). Whether a similar relationship exists between AER and GFR in early diabetes is not known. The present analysis has compared AER and GFR responses to antihypertensive therapy in 33 published studies (77 treatment groups) of early and late DN in type 1 (T1) and type 2 (T2) diabetes, analyzed on an intention-to-treat basis. Prospective trials were included if the initial change in AER during the first year of therapy and the change in GFR during at least 2 years of follow-up could be estimated from group mean data. The initial % decreases in AER were 5.9 +/- 4.3 (T1), 10.5 +/- 5.4 (T2, normotensive) and 18.4 +/- 6.2 (T2, hypertensive) in early DN and 7.6 +/- 11.1 (T1) and 20.8 +/- 5.5 (T2) in late DN. The corresponding annual % rates of decline of GFR were 2.0 +/- 0.5 (T1), 1.6 +/- 0.5 (T2, normotensive) and 2.1 +/- 0.3 (T2, hypertensive) in early DN and 9.8 +/- 1.5 (T1) and 9.2 +/- 1.1 (T2) in late DN. AER and GFR responses in each treatment group were closely correlated in late nephropathy (T1, r = -0.67, p = 0.03; T2, r = 0.57, p = 0.02) but not in early nephropathy. In contrast to late DN, the initial decrease in AER with antihypertensive therapy was not shown to predict the subsequent rate of decline of GFR in early DN. It follows that assessment of renoprotection during antihypertensive therapy in early nephropathy should be based not only on albuminuria but also on the GFR response.

WITHDRAWN: Angiotensin converting enzyme inhibitors in normotensive diabetic patients with microalbuminuria

BACKGROUND

Renal disease is a serious complication of diabetes mellitus.

OBJECTIVES

To examine whether the progression of early diabetic renal disease to end-stage renal failure may be slowed by the use of angiotensin converting enzyme inhibitors for reasons other than their antihypertensive properties, so that they have value in the treatment of normotensive diabetics with microalbuminuria.

SEARCH STRATEGY

Medline was searched for English language reviews and randomised controlled trials. Personal reference lists, and reference lists of retrieved studies were also used.

SELECTION CRITERIA

Randomised controlled trials with separate identifiable results for initially normotensive diabetic patients, who received angiotensin converting enzyme inhibitors for at least one year and were compared with controls.

DATA COLLECTION AND ANALYSIS

Meta-analyses were performed on the results of 12 randomised controlled trials with a variety of patient inclusion and exclusion criteria. One further study met all conditions for inclusion but did not provide data in useable form for meta-analyses.

MAIN RESULTS

Albumin excretion rate fell for patients on angiotensin converting enzyme inhibition in 12 of the 13 studies but did so for only two of the 13 groups on placebo. Treatment provided a significant reduction in albumin excretion rate in both insulin dependent diabetes mellitus and non insulin dependent diabetes mellitus. Treatment with either captopril, enalapril or lisinopril reduced albumin excretion rate in comparison with control patients.A significantly greater lowering of blood pressure was experienced by initially normotensive patients in the angiotensin converting enzyme inhibitor than in the placebo group. Average glycosylated haemoglobin fell a little in the treated patients and rose in the controls, the difference being just significant. The difference in changes in glomerular filtration rate did not reach statistical significance.

AUTHORS' CONCLUSIONS

Inhibition of angiotensin converting enzyme can arrest or reduce the albumin excretion rate in microalbuminuric normotensive diabetics, as well as reduce or prevent an increase in blood pressure. But, given the drop in blood pressure in patients on angiotensin converting enzyme inhibitors, it is not certain that the reduction of albumin excretion rate is due to a separate renal effect. A direct link with postponement of end-stage renal failure has not been demonstrated. There appear to be no substantial side effects.

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.

Probucol delays progression of diabetic nephropathy

Probucol has antioxidant and cholesterol-lowering effects. This study examined the effect of probucol on progression of diabetic nephropathy. We performed a randomized, open trial on 102 type 2 diabetes patients with clinical albuminuria (urinary albumin excretion >300 mg/g Cr). Fifty-one patients were assigned to probucol treatment (500 mg/day) and 51 to no probucol treatment. Among all patients, 40 who had serum creatinine >or=2mg/dl at baseline were defined as advanced cases. All patients were followed for a maximum 3 years. HbA1c levels were not different between two groups. High-density lipoprotein cholesterol decreased significantly in probucol group. Increase in urinary protein (g/day/month) was significantly greater in non-probucol than in probucol group. Hemodialysis was initiated in 23 patients (10 in probucol group and 13 in non-probucol group). The mean interval to initiation of hemodialysis was significantly longer in probucol group (20.7+/-8.2 months) than in non-probucol group (11.3+/-7.4 months). In advanced cases, increases of both serum creatinine and urinary protein were significantly suppressed in probucol group. In advanced cases, the hemodialysis-free rate was significantly higher in probucol group than in non-probucol group. These results suggest that probucol may suppress the progression of diabetic nephropathy.

Primary and secondary prevention of chronic kidney disease

The incidence and prevalence of chronic kidney disease (CKD) is on the rise worldwide. End-stage renal disease (ESRD) is the most advanced form of CKD, requiring some form of renal replacement therapy to ensure survival. Interventions to prevent or slow the progression of CKD, irrespective of the original cause, are thus of significant importance. The most effective of these interventions is based on the inhibition of the renin-angiotensin system (RAS) and is the main focus of this review.

Strategies to retard the progression of chronic kidney disease

Chronic kidney disease (CKD) is a common and, in advanced cases, highly morbid disorder. The most severe form of CKD is end-stage renal disease (ESRD), in which the patient requires some form of renal replacement therapy to survive. The increasing incidence, prevalence, and costs of ESRD are major national health care concerns; interventions that may prevent or slow the progression of CKD towards ESRD are extremely important and the focus of this article.

Treatment of microalbuminuria in patients with type 2 diabetes mellitus

The incidence of type 2 diabetes mellitus is increasing world-wide, and is now one of the leading causes of end-stage renal disease in Western countries. Type 2 diabetes mellitus is also a major risk factor for cardiovascular events. Therefore, the early identification of patients at greatest risk, and the subsequent initiation of renal and cardiovascular protective treatments, are of the utmost importance. Microalbuminuria refers to a subclinical increase in urinary albumin excretion. By definition it corresponds to an albumin excretion rate of 20 to 200 microg/min (30 to 300 mg/day) or an albumin to creatinine ratio (mg/mmol) of 2.5 to 25 in males and 3.5 to 35 in females. Microalbuminuria is an important clinical finding because it is not only associated with an increased risk of progression to overt proteinuria (macroalbuminuria) and renal failure, but also cardiovascular events. In patients who progress to overt nephropathy, microalbuminuria usually precedes macroalbuminuria by an interval of 5 to 10 years. In patients with type 1 diabetes mellitus, blood pressure increases and renal function declines after the onset of macroalbuminuria. However, in patients with type 2 diabetes mellitus, hypertension and a decline in renal function may occur when albumin excretion is still in the microalbuminuric range. Large clinical trials have demonstrated that achieving tight glycemic (i.e. glycosylated hemoglobin < 7.0%) and blood pressure (i.e. < 130/85mm Hg) control retards the progression of renal disease. There is accumulating evidence to suggest that the use of antihypertensive agents which target the renin-angiotensin system (RAS) can slow the progression of renal disease and provide cardioprotection in patients with type 2 diabetes mellitus and microalbuminuria. Antihypertensive agents which target the RAS also appear to have advantages over and above reductions in systemic blood pressure. In summary, the annual screening of patients with type 2 diabetes mellitus for microalbuminuria, and the initiation of measures to retard the progression of renal and cardiovascular disease, are now considered part of routine clinical practice. In particular, the finding of microalbuminuria should provoke an intensified modification of the common risk factors for renal and cardiovascular disease, that is hyperglycemia, hypertension, dyslipidemia and smoking. Antihypertensive therapy in patients with microalbuminuria and type 2 diabetes mellitus should be initiated with angiotensin converting enzyme (ACE) inhibitors or angiotensin-II type 1 receptor antagonists.

Long-term renoprotection by perindopril or nifedipine in non-hypertensive patients with Type 2 diabetes and microalbuminuria

AIMS

To assess the efficacy of an angiotensin converting enzyme (ACE) inhibitor (perindopril), a dihydropyridine calcium channel blocker (sustained release nifedipine) and placebo in preventing the progression of albuminuria and decline in glomerular filtration rate (GFR) in patients with Type 2 diabetes and microalbuminaria.

METHODS

A prospective, randomized, open, blinded end point study of 77 patients allocated to three treatment groups (23 perindopril, 27 nifedipine, 27 placebo). Drug doses were adjusted to achieve a decrease in diastolic blood pressure (DBP) of 5 mmHg in the first 3 months and additional therapy was given if hypertension developed (supine DBP > 90 mmHg and/or systolic blood pressure (SBP) > 140 mmHg if < or = 40 years; supine DBP > 90 mmHg and/or SBP > 160 mmHg if > 40 years). Median follow-up was 66 months, with 37 patients being followed for at least 6 years.

RESULTS

Blood pressure remained within the non-hypertensive range in 83% of perindopril-, 95% of nifedipine- and 30% of placebo-treated patients (P < 0.01). In the first 12 months albumin excretion rate (AER) decreased by 47% only in the perindopril group (P = 0.04). From 12 to 72 months, AER gradients increased by 27% per year only in the placebo group (P < 0.01). After 6 years, macroalbuminuria had developed in 7/15 placebo compared with 2/11 in perindopril and 1/11 nifedipine-treated patients (P = 0.05). GFR did not change in the first 12 months, but thereafter the median GFR gradient (ml/min/1.73 m(2) per year) was -2.4 (P < 0.01) for perindopril-, -1.3 (P = 0.26) for nifedipine- and -4.2 (P = 0.01) for placebo-treated patients. The rate of decline in GFR for the study group as a whole from 12 months to the end of follow-up correlated negatively with mean arterial pressure (MAP) (r = -0.38, P < 0.01). During a 3-month treatment pause in 29 patients AER tended to increase only in the perindopril group (P < 0.07).

CONCLUSIONS

Long-term control of blood pressure with perindopril or nifedipine stabilizes AER and attenuates GFR decline in proportion to MAP in non-hypertensive patients with Type 2 diabetes and microalbuminuria.

Slowing the Progression of Adult Chronic Kidney Disease

When kidney disease of any aetiology results in substantial loss of nephrons, a common clinical syndrome, characterised by hypertension, proteinuria and a progressive decline in renal function, ensues. This observation suggests that common mechanisms may contribute to progressive renal injury and that therapeutic interventions that inhibit these common pathways may afford renal protection. Research to date has identified several mechanisms that may contribute to progressive renal injury including glomerular haemodynamic changes, multiple effects of angiotensin II and detrimental effects of excessive filtration of plasma proteins by injured glomeruli. Clinical trials over the past decade have identified several interventions that are effective in slowing the rate of progression of chronic kidney disease (CKD). The use of ACE inhibitors, angiotensin receptor antagonists or a combination of the two should be regarded as fundamental to any therapy for slowing the rate of CKD progression. Hypertension should be treated aggressively to achieve a blood pressure target of < 130/80 mm Hg. Reduction of proteinuria to < 0.5 g/day should be regarded as an independent therapeutic goal. Although inconclusive, there is some evidence to support moderate dietary protein restriction to 0.6 g/kg/day in appropriate patients. Hyperlipidaemia may contribute to CKD progression and should be treated to reduce cardiovascular risk and potentially improve renal protection. Smoking cessation should be encouraged and, where necessary, assisted. Among diabetic patients tight glycaemic control should be achieved (glycosylated haemoglobin < 7%). These interventions are simple and relatively inexpensive. If applied to all patients with CKD they will result in substantial slowing of renal function decline in many patients and thereby reduce the number who progress to end-stage renal disease and require renal replacement therapy.

Hypertension in people with Type 2 diabetes: knowledge-based diabetes-specific guidelines

The International Diabetes Federation (Europe) has updated these guidelines on hypertension management specifically in Type 2 diabetes in the light of recent results of the first prospective, randomized controlled studies to investigate clinical outcomes in people with diabetes and hypertension. The guidelines are knowledge based, i.e. based not only on evidence originating from clinical trials, but also from epidemiological and pathophysiological studies. A successful management strategy requires the following components: 1. Regular surveillance to detect developing hypertension and other cardiovascular (CV) risk factors. 2. Considering more frequent monitoring and review of CV risk factors if any single blood pressure (BP) measurement > 140/85 mmHg (or 130/75 if microalbuminuria); when appropriate, using ambulatory or home monitoring to establish the baseline BP. 3. Considering other CV risk factors, such as a raised albumin excretion rate, in setting the intervention threshold. 4. Individualizing the target BP in accordance with other CV risk factors. 5. Agreeing lifestyle and therapeutic interventions with the patient, with education and empowerment as required. 6. Implementing lifestyle modifications, including controlling calorie, salt and alcohol intake, increased physical activity, weight control and smoking cessation. 7. Therapeutic strategy: the primary goal of therapy is to reduce BP markedly. Combination therapy is often necessary, e.g. an angiotensin converting enzyme (ACE) inhibitor and a diuretic. Some classes are particularly useful for certain patients, notably longer-acting ACE inhibitors, angiotensin 2 receptor antagonists (A2RAs) and calcium antagonists in those at risk of diabetic nephropathy, loop diuretics and thiazides in those at risk of hyperkalaemia, beta-blockers and calcium antagonists (except short-acting dihydropyridines) in patients with angina, beta-blockers and ACE inhibitors after a myocardial infarction or in those with left ventricular dysfunction, and thiazide diuretics and long-acting dihydropyridine calcium antagonists for isolated systolic hypertension. A2RAs should be particularly considered when ACE inhibitors are not tolerated. alpha 1-Blockers should not be considered first line in the absence of outcome data. Cost of drugs will modify these strategies in developing countries. 8. Monitoring response to therapies and, if target levels are not achieved, either intensifying drug therapy if the CV risk justifies it, or reassessing the target. 9. Maintaining a quality assurance strategy. This strategy is summarized in a simple, practical management algorithm.

The renin-angiotensin system and the long-term complications of diabetes: pathophysiological and therapeutic considerations

The relationship between the renin-angiotensin system (RAS) and the progression of diabetic renal disease has been a major focus of investigation over the past 20 years. More recently, experimental and clinical studies have also suggested that the RAS may have a pathogenetic role at other sites of micro- and macrovascular injury in diabetes. Complementing major advances into the understanding of the local, as distinct from the systemic RAS, a number of large clinical trials have examined whether blockade of the RAS might provide protection from the long-term complications of diabetes, beyond that due to blood pressure reduction alone. While some controversy remains, these studies have, in general, suggested that angiotensin converting enzyme (ACE) inhibition and more recently, angiotensin receptor blockade reduce the development and progression of diabetic nephropathy, cardiovascular disease and possibly retinopathy. This review will focus on recent developments in our understanding of the tissue-based RAS and its role in end-organ injury in diabetes, the results of recent clinical trials and newer strategies for the pharmacological manipulation of the RAS.

Lessons from trials in hypertensive type 2 diabetic patients

There is incontrovertible evidence that association of type 2 diabetes with hypertension markedly increases the risk of cardiovascular events, death, and nephropathy. In type 2 diabetes, even blood pressure values usually considered below the threshold for hypertension (ie, 140/90 mm Hg) in nondiabetic subjects represent an additional risk of clinical relevance. Evidence that more intensive blood pressure lowering is beneficial in type 2 diabetes over less intensive lowering is also overwhelming. However, most published trials show the need for combination therapy in the great majority of patients, and even with combination therapy it is difficult to attain the expected goal blood pressure, in particular goal systolic blood pressure. It should be recognized that the systolic blood pressure goal of less than 130 mm Hg is a very difficult one to achieve in diabetics. Evidence of the superiority or inferiority of different drug classes is vague and contradictory. Recent evidence concerning angiotensin II receptor antagonists has shown a significant reduction of cardiovascular events, cardiovascular death, and total mortality when losartan was compared with atenolol, but not when irbesartan was compared with amlodipine. If renal endpoints are considered, evidence of the benefit of angiotensin II receptor antagonists in type 2 diabetes is more robust than that available with angiotensin-converting enzyme inhibitors. Primary prevention of development of microalbuminuria seems to be greatly facilitated by strict blood pressure control. However, by attaining normal blood pressure levels (< 130/80 mm Hg), better preservation of glomerular filtration rate does not seem to be insured.

ACE inhibition or angiotensin receptor blockade: which should we use in diabetic patients?

Blockade of the effects of angiotensin II (Ang II) by using an angiotensin-converting enzyme (ACE) inhibitor has been proven to be of value in Type 1 diabetic nephropathy and in non-diabetic renal disease. Evidence in favour of Ang II blockade in Type 2 diabetic patients with renal damage is still lacking for ACE inhibitors (ACE-Is), while recent data indicate that angiotensin receptor blockers (ARBs) could be the drugs of choice in this situation. On the other hand, renal damage from the onset of disease is accompanied by a very significant increment in global cardiovascular risk. This fact, as well as that of simultaneous renal and cardiovascular protection, have to be considered for drug selection. In this sense, ACE-Is have been shown to be the drugs of choice when secondary cardiovascular prevention is required, while the evidence in primary prevention in hypertensive patients has been shown with losartan in the Losartan Intervention For Endpoint reduction in hypertension (LIFE) study. All these facts led to the conclusion that both ACE-Is and ARBs can be considered when both renal and cardiovascular protection are aimed for in Type 2 diabetic patients.

Comparative effects of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers on blood pressure and the kidney

Many clinicians are uncomfortable about using angiotensin-converting enzyme (ACE) inhibitors or angiotensin II type 1 receptor blockers (AT(1)-blockers) to treat patients with renal disease because of concerns about increasing serum creatinine levels. However, the benefits of these medications, particularly their efficacy in slowing the progression of renal disease, outweigh such concerns. ACE inhibitors are effective in patients with type 1 diabetes and renal disease, as well as in those with nondiabetic renal disease and proteinuria >0.5 g/d. AT(1)-blockers slow the progression of diabetic nephropathy in patients with type 2 diabetes. Although these classes of medications should not be used in patients with severe renal insufficiency (e.g., glomerular filtration rate <20 mL/min), they may be beneficial in patients with mild-to-moderate renal insufficiency. Nonetheless, caution should be exercised in those with a glomerular filtration rate <30 mL/min, and serum creatinine and potassium levels should be checked approximately 1 week after starting treatment. There is also evidence suggesting that these medications lead to greater reductions in blood pressure and proteinuria when used in combination than when alone. The purpose of this paper is to review the mechanisms of action of these two classes of medication, as well as the experimental and clinical evidence that they slow the progression of renal disease.

Pharmacologic management of diabetic nephropathy

BACKGROUND

Diabetes mellitus and hypertension are leading causes of end stage renal disease in the United States. Drug therapy that focuses on tight glycemic control and blood pressure control reduces the progression of nephropathy and cardiovascular complications. Angiotensin-converting enzyme (ACE) inhibitors have been shown to reduce the progression of renal disease in patients with diabetes. The angiotensin II receptor blockers (ARBs) losartan and irbesartan have also been shown to reduce microalbuminuria compared with placebo. The nondihydropyridine calcium channel blockers (CCBs) verapamil and diltiazem have been shown to be as effective as an ACE inhibitor in reducing urinary albumin excretion.

OBJECTIVE

This paper reviews the pathophysiology and diagnosis of diabetic nephropathy and recent clinical trials assessing the most appropriate therapeutic options for delaying the progression of nephropathy in patients with diabetes.

METHODS

Primary and review articles that addressed the pathophysiology, diagnosis, and therapeutic options for attenuating the progression of diabetic nephropathy were retrieved through a MEDLINE search (January 1990 to August 2002) and the bibliographies of identified articles were reviewed. English-language sources were searched using the following search terms: diabetes mellitus, nephropathy, proteinuria, ACE inhibitors, and ARBs. Studies published in peer-reviewed journals that were determined to be methodologically sound, with appropriate statistical analysis of the results, were selected for inclusion in this review.

RESULTS

Patients with type 1 diabetes mellitus and evidence of nephropathy should be started on an ACE inhibitor unless contraindicated. The ARBs and ACE inhibitors are viable choices for patients with type 2 diabetes mellitus and evidence of proteinuria. Patients who experience adverse events such as dry cough with ACE inhibitors can be switched to ARBs. Clinical literature suggests that if monotherapy with an ACE inhibitor or ARB does not provide an adequate response, a nondihydropyridine CCB should be added to the regimen. Nondihydropyridine CCBs should also be considered when ACE inhibitors and ARBs are contraindicated.

CONCLUSIONS

ACE inhibitors and ARBs should be considered first-line therapy for patients with type 2 diabetes mellitus and nephropathy. The ACE inhibitors are still the drug of choice for patients with type 1 diabetes mellitus and evidence of incipient or overt nephropathy. If therapeutic goals are not achieved with an ACE inhibitor or ARB, then the addition of a nondihydropyridine CCB should be considered.

Angiotensin-converting enzyme activity is involved in the mechanism of increased endogenous nitric oxide synthase inhibitor in patients with type 2 diabetes mellitus

The renin-angiotensin system plays an important role in the elevation of asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase, in hypertensive patients, so the present study was designed to examine whether angiotensin-converting enzyme (ACE) activity is also involved in the mechanism of ADMA elevation in type 2 diabetes mellitus (NIDDM). A crossover study was performed to determine if ACE inhibition with perindopril (4 mg/day) for 4 weeks decreases serum ADMA concentration and plasma von Willebrand factor (vWF) level (a marker of endothelial injury) in 11 patients with NIDDM. None of the patients was treated with insulin or oral hypoglycemic drugs, and none had major diabetic complications. Before the protocol began, serum ADMA and plasma vWF were significantly higher in the 11 NIDDM patients, when compared with 8 control subjects without diabetes. Perindopril did not affect blood pressure or glucose metabolism, but did significantly decrease serum ADMA and plasma vWF. These results suggest that endothelial injury associated with ADMA elevation may be present even in patients with non-complicated NIDDM, and that increased activity of ACE may be involved in such endothelial dysfunction.

Calcium channel blockade in combination with angiotensin-converting enzyme inhibition or angiotensin II (AT(1)-receptor) antagonism in hypertensive diabetics and patients with renal disease and hypertension

Effective reduction in blood pressure (BP) improves survival and morbidity in hypertensive patients. Combination therapy with multiple antihypertensive agents is frequently required in clinical practice and therapeutic trials to achieve target BP. Patients at elevated cardiovascular risk achieve the greatest benefit from equivalent reduction in BP and also require more stringent BP control. In patients with hypertension and diabetes mellitus or renal disease, BP control is of primary importance and blockade of the renin-angiotensin system (RAS) should be the initial therapeutic intervention. Choice of combination therapy has been insufficiently studied in major clinical cardiovascular endpoint trials. Diuretic therapy remains the logical addition to RAS blockade. Despite previous debate, the available evidence suggests long-acting calcium-channel blockers are also a safe and very effective addition to improve BP control further. The choice of antihypertensive combination therapy should not override the fundamental necessity of lowering BP to target levels.

Microalbuminuria: marker of vascular dysfunction, risk factor for cardiovascular disease

Based on the data from large single and multi-center clinical trials, including the Heart Outcomes Prevention Evaluation (HOPE) study, it is clear that the presence of microalbuminuria is a signal from the kidney that cardiovascular risk is increased and that vascular responses are altered. This is exemplified by studies that have demonstrated that the compensatory vasodilation seen following relief from prolonged ischemia or infusion of vasodilators such as nitroglycerin is blunted in people with microalbuminuria. Thus, the presence of between 30 and 299 mg/day of albumin in the urine is associated with abnormal vascular responsiveness, which may be the result of more advanced atherosclerosis and not necessarily related to the presence of hypertension or renal disease. Agents known to reduce the rise in microalbuminuria or actually reduce the level of microalbuminuria, such as ACE inhibitors, angiotensin receptor blockers, HMG-CoA reductase inhibitors, beta blockers, non-dihydropyridine calcium channel blockers and diuretics, have all been shown to reduce cardiovascular mortality and in some cases preserve renal function. This article will present an overview of the data that support the assertion that a reduction in the rise of microalbuminuria is a significant consideration in the selection of agents to treat a given risk factor (cholesterol or blood pressure) to a recommended target goal. Achieving such a goal with agents that also impact microalbuminuria will provide for a more complete cardiovascular risk reduction.

Treatment of hypertension in diabetic patients with nephropathy

In type 1 diabetes, hypertension is closely linked to the development of nephropathy. An association of hypertension and the impact of hypertension on the clinical course of type 2 diabetes, including the development of vascular complications, has been well established. However, the association with nephropathy in type 2 diabetes is less clear. Despite that, antihypertensive treatment has a crucial impact on the course of nephropathy in both types of diabetes. In this article, we discuss recent evidence focusing on the nephroprotective potential of various classes of antihypertensive agents and confront it with current recommendations for the treatment of hypertension in diabetic patients with nephropathy. Unlike type 1 diabetes, where the nephroprotection could be a good sole measure for assessing the efficiency of a particular agent or their combination, defining of the optimal antihypertensive agent or agents in type 2 diabetes requires consideration of both cardiovascular, cerebrovascular, and nephroprotective potentials of such a treatment. In both types of diabetes, recent data support the use of inhibitors of the renin-angiotensin system with or without diuretics as the initial therapy. In type 1 diabetes, additional beneficial effect can be expected from calcium channel blockers (CCBs). In type 2 diabetic patients, combining more agents may be necessary early in the course of nephropathy to affect both micro- and macrovascular targets. beta blockers should be applied early to enhance cardioprotectivity, followed by CCBs to achieve goal blood pressure. Although not supported by all recent data, aggressive blood pressure control (< 130/75 mm Hg) is warranted. Furthermore, multifactorial intervention targeting metabolic derangements and lifestyle, is a necessary complimentary measure that must accompany antihypertensive treatment.

Evolving strategies for renoprotection: diabetic nephropathy

A cumulative incidence of diabetic nephropathy of 25-40% has been documented after duration of diabetes of at least 25 years in both type 1 and type 2 diabetic patients. Diabetic nephropathy has become the leading cause (25-44%) of end-stage renal failure in Europe, the United States and Japan. Until the early 1980s, no renoprotective treatment was available for use in diabetic nephropathy. Death occurred on average 5-7 years after the onset of persistent proteinuria. It should be recalled that development of treatment modalities occurred in reverse order: in the early 1980s, antihypertensive treatment of diabetic nephropathy was introduced, and in the early 1990s, primary and secondary prevention with improved glycaemic control and angiotensin-converting enzyme inhibition. The two main treatment strategies for primary prevention of diabetic nephropathy are improved glycaemic control and blood pressure lowering, particularly using drugs such as angiotensin-converting enzyme inhibitors. Megatrials and meta-analyses have clearly demonstrated the beneficial effect of both the above-mentioned treatment modalities. Secondary prevention, that is, treatment modalities applied to diabetic patients with high risk of development of diabetic nephropathy (e.g. those with microalbuminuria) has been documented, applying angiotensin-converting enzyme inhibitors in both type 1 and type 2 diabetic patients. Furthermore, improved metabolic control reduces the risk of progression. In special cases (such as pancreas transplantation) even reversal of diabetic glomerular lesions has been documented. Antihypertensive treatment of patients with overt nephropathy induces a reduction in albuminuria, a reduction in the rate of decline of glomerular filtration rate, delays development of end-stage renal failure and improves survival. Many potential treatment modalities in preventing and treating diabetic nephropathy are presently being evaluated.

Slowing the progression of renal disease in diabetic patients

OBJECTIVE

To review recent clinical trials that evaluate the most appropriate therapeutic options for delaying the progression of nephropathy in type 2 diabetic patients.

DATA SOURCES

Primary and review articles were retrieved through a MEDLINE search (January 1990-January 2000).

STUDY SELECTION AND DATA EXTRACTION

All studies related to attenuating the progression of nephropathy in diabetic patients were evaluated and included in this review.

DATA SYNTHESIS

Clinical trials with angiotensin-converting enzyme inhibitors (ACEI) have consistently demonstrated a decrease in the progression of renal disease in diabetic patients. The angiotensin-2 receptor blocker (ARB) losartan has been shown to reduce microalbuminuria to the same extent as the ACEI enalapril. The nondihydropyridine calcium-channel blockers (NCCBs) verapamil and diltiazem have also been shown to decrease urinary albumin excretion. Clinical literature suggests that if monotherapy with an ACEI or ARB does not provide an adequate response, an NCCB should be added to the regimen.

CONCLUSIONS

ACEIs should be considered first-line therapy for diabetic patients with nephropathy. ARBs should be considered as an alternative for patients who are unable to tolerate an ACE inhibitor due to adverse effects. If blood pressure goals are not achieved with an ACEI or ARB, then the addition of an NCCB should be considered.

Microalbuminuria in patients with Type 2 diabetes mellitus from general practice: course and predictive value

AIMS

To assess the course of microalbuminuria in patients with Type 2 diabetes mellitus in general practice and the predictive value of urinary albumin concentration on all-cause mortality, cardiovascular mortality and cardiovascular morbidity.

METHODS

Cohort study in Type 2 diabetic patients tested for microalbuminuria in 1992, and re-tested in 1998. During follow-up all cardiovascular morbidity and mortality were recorded.

RESULTS

Of the original sample of 317 patients, 163 patients were re-tested. The mean change in urinary albumin concentration was +16.2 mg/l (range -122.0 to +602 mg/l). Seventy-five per cent of the patients without microalbuminuria in 1992 still had no microalbuminuria in 1998 and 40% of those with microalbuminuria in 1992 reverted to normoalbuminuria in 1998. Cox survival analysis, stratified for age, showed that microalbuminuria at baseline resulted in a risk ratio of all-cause mortality of 1.4 (95% confidence interval 0.8-2.7), of cardiovascular mortality of 1.2 (0.5-2.8) and of new cardiovascular events (including cardiovascular mortality) of 1.4 (0.8-2.3).

CONCLUSIONS

In the majority of patients the change of urinary albumin excretion was small, but the range was wide. A weak non-significant relationship between microalbuminuria and all-cause mortality and cardiovascular morbidity was observed.

Angiotensin converting enzyme inhibitors in normotensive diabetic patients with microalbuminuria

OBJECTIVES

To examine whether the progression of early diabetic renal disease to end-stage renal failure may be slowed by the use of angiotensin converting enzyme inhibitors for reasons other than their antihypertensive properties, so that they have value in the treatment of normotensive diabetics with microalbuminuria.

SEARCH STRATEGY

Medline was searched for English language reviews and randomised controlled trials. Personal reference lists, and reference lists of retrieved studies were also used.

SELECTION CRITERIA

Randomised controlled trials with separate identifiable results for initially normotensive diabetic patients, who received angiotensin converting enzyme inhibitors for at least one year and were compared with controls.

DATA COLLECTION AND ANALYSIS

Meta-analyses were performed on the results of 12 randomised controlled trials with a variety of patient inclusion and exclusion criteria. One further study met all conditions for inclusion but did not provide data in useable form for meta-analyses.

MAIN RESULTS

Albumin excretion rate fell for patients on angiotensin converting enzyme inhibition in 12 of the 13 studies but did so for only two of the 13 groups on placebo. Treatment provided a significant reduction in albumin excretion rate in both insulin dependent diabetes mellitus and non insulin dependent diabetes mellitus. Treatment with either captopril, enalapril or lisinopril reduced albumin excretion rate in comparison with control patients. A significantly greater lowering of blood pressure was experienced by initially normotensive patients in the angiotensin converting enzyme inhibitor than in the placebo group. Average glycosylated haemoglobin fell a little in the treated patients and rose in the controls, the difference being just significant. The difference in changes in glomerular filtration rate did not reach statistical significance.

REVIEWER'S CONCLUSIONS

Inhibition of angiotensin converting enzyme can arrest or reduce the albumin excretion rate in microalbuminuric normotensive diabetics, as well as reduce or prevent an increase in blood pressure. But, given the drop in blood pressure in patients on angiotensin converting enzyme inhibitors, it is not certain that the reduction of albumin excretion rate is due to a separate renal effect. A direct link with postponement of end-stage renal failure has not been demonstrated. There appear to be no substantial side effects.