Captopril or conventional therapy in hypertensive type II diabetics. Three-year analysis

The effect of renin-angiotensin-aldosterone system inhibitors on continuous and binary kidney outcomes in subgroups of patients with diabetes: a meta-analysis of randomized clinical trials

Introduction

Diabetic nephropathy is the leading cause of kidney failure. Clinical practice guidelines recommend prescribing renin–angiotensin aldosterone system inhibitors (RAASi) to prevent diabetic nephropathy at any stage. We conducted this systematic review and meta-analysis to compare the effects of RAASi with placebo and other antihypertensive agents in adults with diabetes on continuous and binary kidney outcomes to provide a comprehensive review of the class effect of RAASi on several subgroups.

Methods

A systematic electronic search to identify randomized clinical trials of a duration of ≥ 12 months that recruited ≥ 50 adult participants with type 1 or 2 diabetes with any stage of chronic kidney disease and proteinuria was conducted in MEDLINE, CINAHL, EMBASE, and Cochrane library with no language restriction. Studies were screened against the inclusion and exclusion criteria by two reviewers independently.

Results

In this meta-analysis, evidence was drawn from 26,551 patients with diabetes from 46 studies. Our analysis shows that RAASi were better than placebo in reducing SrCr (the raw mean difference [RMD] = -13.4 μmol/L; 95%CI: -16.78; -10.01) and albuminuria levels (standardized mean difference [SMD] = -1; 95%CI: -1.57, -0.44, I² = 96%). When compared to other active treatments, RAASi did not reduce SrCr (RMD = 0.03 μmol/L; 95%CI: -6.4, 6.10, I² = 76%), caused a non-significant reduction of GFR levels (RMD = -1.21 mL/min; 95%CI: -4.52, 2.09, I² = 86%), and resulted in modest reduction of albuminuria levels (SMD = -0.55; 95%CI: -0.95, -0.16, I² = 90%). RAASi were superior to placebo in reducing the risks of kidney failure (OR = 0.74; 95%CI: 0.56, 0.97) and doubling of serum creatinine levels (SrCr; OR = 0.71; 95%CI: 0.55, 0.91), but not in promoting the regression of albuminuria (OR = 3.00; 95%CI: 0.96, 9.37). RAASi, however, were not superior to other antihypertensives in reducing the risks of these outcomes. Patients with type 2 diabetes, macroalbuminuria and longer duration of diabetes had less risk of developing kidney failure in placebo-controlled trials, while longer duration of diabetes, normal kidney function, and hypertension increased the probability of achieving regression of albuminuria in active-controlled trials.

Conclusion

While our findings revealed the non-superiority of RAASi over other antihypertensives and portrayed a class effect on several subgroups of study participants, it raised a challenging question on whether RAASi deserve their place as first-line therapy in managing diabetic nephropathy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-022-02763-1.

Association of heart rate with albuminuria in a general adult population: the 2011 Korea National Health and Nutrition Examination Survey

BACKGROUND

Albuminuria is associated with increased risk of multiple adverse health outcomes, such as progressive renal failure, cardiovascular disease and death. However, in the general population, it is uncertain whether albuminuria is associated with elevated heart rate, which is an independent and powerful risk factor for cardiovascular disease.

AIM

To investigate whether an elevated heart rate is an independent factor associated with albuminuria in the general adult population of Korea.

METHODS

A cross-sectional analysis was carried out on 5198 Korean adults aged 19 years or older who participated in the fifth (2011) Korea National Health and Nutrition Examination Survey (KNHANES V-2).

RESULTS

The prevalence of albuminuria showed an increasing trend throughout the whole range of heart rate, even after adjusting for confounders (P = 0.002). The increment was most profound at the heart rate of 70-75 and >76 beats per minute (b.p.m.; P = 0.011). In multiple logistic regression analysis, age (P < 0.001), hypertension (P < 0.001), diabetes (P < 0.001), hypertriglyceridaemia (P = 0.025), estimated glomerular filtration rate (P = 0.028) and heart rate (P = 0.023) were independently associated with the presence of albuminuria in Korean adults. Compared with participants with heart rate ≤ 64 b.p.m., the odds ratio (95% CI) for albuminuria was 1.50 (1.15-1.96) for those with heart rate ≥ 76 b.p.m.

CONCLUSIONS

The prevalence of albuminuria is independently associated with heart rate in the general adult population of Korea.

Reno-protective effects of renin-angiotensin system blockade in type 2 diabetic patients: a systematic review and network meta-analysis

AIMS/HYPOTHESIS

This meta-analysis aimed to compare the renal outcomes between ACE inhibitor (ACEI)/angiotensin II receptor blocker (ARB) and other antihypertensive drugs or placebo in type 2 diabetes.

METHODS

Publications were identified from Medline and Embase up to July 2011. Only randomised controlled trials comparing ACEI/ARB monotherapy with other active drugs or placebo were eligible. The outcome of end-stage renal disease, doubling of serum creatinine, microvascular complications, microalbuminuria, macroalbuminuria and albuminuria regression were extracted. Risk ratios were pooled using a random-effects model if heterogeneity was present; a fixed-effects model was used in the absence of heterogeneity.

RESULTS

Of 673 studies identified, 28 were eligible (n = 13-4,912). In direct meta-analysis, ACEI/ARB had significantly lower risk of serum creatinine doubling (pooled RR = 0.66 [95% CI 0.52, 0.83]), macroalbuminuria (pooled RR = 0.70 [95% CI 0.50, 1.00]) and albuminuria regression (pooled RR 1.16 [95% CI 1.00, 1.39]) than other antihypertensive drugs, mainly calcium channel blockers (CCBs). Although the risks of end-stage renal disease and microalbuminuria were lower in the ACEI/ARB group (pooled RR 0.82 [95% CI 0.64, 1.05] and 0.84 [95% CI 0.61, 1.15], respectively), the differences were not statistically significant. The ACEI/ARB benefit over placebo was significant for all outcomes except microalbuminuria. A network meta-analysis detected significant treatment effects across all outcomes for both active drugs and placebo comparisons.

CONCLUSIONS/INTERPRETATION

Our review suggests a consistent reno-protective effect of ACEI/ARB over other antihypertensive drugs, mainly CCBs, and placebo in type 2 diabetes. The lack of any differences in BP decrease between ACEI/ARB and active comparators suggest this benefit is not due simply to the antihypertensive effect.

Evidence-based guide to slowing the progression of early renal insufficiency

Early renal insufficiency (ERI), defined as a calculated or measured glomerular filtration rate (GFR) between 30 and 60 mL/min per 1.73 m2, is present in more than 10% of the adult Australian population. This pernicious condition is frequently unrecognised, progressive and accompanied by multiple associated comorbidities, including hypertension, renal osteodystrophy, anaemia, sleep apnoea, cardiovascular disease, hyperparathyroidism and malnutrition. Several treatments have been suggested to retard GFR decline in ERI, including blood pressure reduction, angiotensin-converting enzyme inhibition, angiotensin receptor antagonism, calcium channel blockade, cholesterol reduction, smoking cessation, erythropoietin therapy, dietary protein restriction, intensive glycaemic control and early intensive multidisciplinary patient education within a renal unit. In addition, specific interventions have been reported to be renoprotective in atherosclerotic renal artery stenosis, diabetic nephropathy, lupus nephritis and certain forms of primary glomerulonephritis. The present paper reviews the available published randomised controlled clinical trials and meta-analyses supporting (or refuting) a role for each of these therapeutic manoeuvres.

Association of heart rate with microalbuminuria in cardiovascular risk patients: data from I-SEARCH

BACKGROUND

Microalbuminuria (MAU) is an indicator of impaired renal function and a relevant risk predictor for cardiovascular events. An increased heart rate is closely correlated with increased cardiovascular mortality. The International Survey Evaluating Microalbuminuria Routinely by Cardiologists in Patients with Hypertension (I-SEARCH) investigated 21 050 patients with hypertension and risk factors for cardiovascular disease. In patients in sinus rhythm (n = 18 900) the relationship between increased heart rate and the prevalence of MAU was analysed.

METHODS AND RESULTS

The study was performed in 26 countries worldwide from September 2005 to March 2006. Heart rate, blood pressure, urine albumin and serum creatinine were measured as key parameters. With increasing heart rate (> 80 bpm to < 120 bpm) the proportion of patients with MAU increased from 63 to 69% (P < 0.0001). The odds ratio (OR) for MAU increased with increasing heart rate [heart rate 80-100 bpm compared with 60 bpm: OR, 1.47; 95% confidence interval (CI), 1.29-1.68; P < 0.0001; and heart rate 100-120 bpm compared with 60 bpm: OR, 1.56; 95% CI, 1.22-1.99; P = 0.0004]. The prevalence of MAU was similar whether or not patients were receiving beta-blockers; but MAU was significantly reduced in physically active patients compared with sedentary patients (OR, 0.78; 95% CI, 0.73-0.84; P < 0.0001).

SUMMARY

These results show that heart rate is an independent predictor for the prevalence of MAU in hypertensive patients with cardiovascular risk factors. In contrast to beta-blocker therapy, physical activity markedly decreased MAU with increasing heart rates. Further controlled and prospective studies are needed to show that lowered heart rates in combination with MAU can significantly reduce kidney damage, as well as cardiovascular events.

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.

Irbesartan treatment of patients with type 2 diabetes, hypertension and renal disease: a UK health economics analysis

The objective of the study was to determine the impact of irbesartan treatment on life expectancy (LE), costs and progression to end-stage renal disease (ESRD) in hypertensive type 2 diabetes patients. A peer-reviewed and published Markov model was used to simulate progression from microalbuminuria to overt nephropathy, doubling of serum creatinine, ESRD and all-cause mortality in hypertensive patients with type 2 diabetes. Three treatment strategies were evaluated: (i) 'control' regimen of conventional antihypertensive therapy (excluding angiotensin-converting enzyme inhibitors, angiotensin-2-receptor antagonists and dihydropyridine calcium-channel blockers), (ii) 'early irbesartan' 300 mg daily and (iii) 'late irbesartan' 300 mg daily (started when overt nephropathy developed). Transition probabilities determining nephropathy progression were taken from the Irbesartan in Reduction of Microalbuminuria-2 study, Irbesartan in Diabetic Nephropathy Trial and other published sources. Outcomes were projected over 25 years. The mean +/- SD cumulative incidence of ESRD was reduced by 8.8% +/- 0.6 and 12.4% +/- 0.7 in patients treated with early irbesartan compared with late irbesartan and control respectively. Early irbesartan treatment improved undiscounted LE by 1.38 +/- 0.08 years (discounted: 0.81 +/- 0.04 years) compared with late irbesartan and 1.41 +/- 0.08 years (discounted: 0.83 +/- 0.04 years) compared with control. Early irbesartan treatment was projected to save (mean +/- SD) pounds 2310 +/- 327 and pounds 3801 +/- 327 over patient lifetimes compared with late irbesartan and control respectively. Irbesartan treatment is predicted to improve survival and reduce costs in hypertensive patients with type 2 diabetes and microalbuminuria compared with 'control'. Early irbesartan treatment is more effective than late irbesartan. Irbesartan is a valuable treatment option in this patient group in a UK setting.

Should β-Blockers Be Used to Control Hypertension in People With Chronic Kidney Disease?

Activation of the sympathetic nervous system is common in patients with chronic kidney disease, plays an important role in the genesis of hypertension, the rate of decrease of renal function, and is associated with the increased cardiovascular morbidity and mortality seen in these patients. beta-blockers are potent antihypertensive agents but differ in their hemodynamic effects on renal function. The cardioselective beta-blockers such as atenolol and metoprolol are known to retard the progression of renal diseases, but to a lesser degree compared with blockers of the renin-angiotensin-aldosterone system. However, the newer vasodilating beta-blockers such as carvedilol and nebivolol have different effects on renal hemodynamics and function primarily because of its greater adjunctive alpha1-blocking activity. Carvedilol decreases renal vascular resistance and prevents reductions in the glomerular filtration rate and renal blood flow in patients with hypertension with or without impaired kidney function. In addition, carvedilol may retard progression of albuminuria, and provide cardiorenal protection in chronic kidney disease patients with hypertension, congestive heart failure, and at high risk for sudden cardiac death.

Health economic implications of irbesartan treatment versus standard blood pressure control in patients with type 2 diabetes, hypertension and renal disease: a Hungarian analysis

To perform a health economic analysis on treatment with irbesartan in patients with type 2 diabetes and hypertension. A Markov model was adapted to the Hungarian setting to simulate renal deterioration from the development of microalbuminuria to nephropathy, doubling of serum creatinine, end-stage renal disease (ESRD) and all-cause mortality. Outcomes for two treatments were evaluated: (1) a placebo regimen of standard antihypertensive medications, and (2) the addition of irbesartan 300 mg administered daily, with both treatment initiated after developing microalbuminuria. Outcomes were discounted at 5% annually to correspond with national guidelines. Treatment with irbesartan was estimated to improve undiscounted life expectancy by 0.98 +/- 0.05 years, reduce the cumulative incidence of ESRD by 7.5 +/- 0.4%, and reduce lifetime costs by Hungarian Forints (HUF) 519,993 +/- 70,814, compared to placebo. Irbesartan was projected to improved life expectancy and reduce costs compared to placebo in the Hungarian setting in hypertensive patients with type 2 diabetes and microalbuminuria.

Beta blockers in the management of chronic kidney disease

The sympathetic nervous system modulates renal function through its receptors namely beta1 (cardiac output and renin release), alpha1 (systemic and renovascular constriction), and beta2 renovascular dilation. Sympathetic overactivity is commonly seen in chronic kidney disease (CKD) and is an important contributor to increasing the risk of cardiovascular events as well as increasing renal disease progression. Recent evaluations of drug use in people with CKD shows a remarkably low percentage of patients receiving beta-blockers, especially in more advanced stage CKD when cardiovascular risk is higher. This is in large part due to tolerability of these agents. Moreover, water-soluble beta-blockers such as atenolol and metoprolol are dialyzable and require supplementation to avoid exacerbation of arrhythmias following dialysis. Newer vasodilating beta-blockers have better tolerability and different effects on renal hemodynamics as well as metabolic variables. These effects are related to the relative alpha1-blocking effect of agents such as carvedilol and labetolol, with carvedilol having relatively greater alpha-blocking effects. Few studies evaluate beta-blockers on cardiovascular risk in CKD patients. Studies with carvedilol demonstrate attenuated increases in albuminuria as well as reduction in cardiovascular events in CKD patients with hypertension. This paper reviews the animal and clinical trial data that evaluate beta-blockers in CKD highlighting the vasodilating beta-blockers. It is apparent that greater use of this drug class for blood pressure control would further enhance reduction of risk of heart failure, the most common cause of death in the first year of starting dialysis.

Irbesartan treatment reduces biomarkers of inflammatory activity in patients with type 2 diabetes and microalbuminuria: an IRMA 2 substudy

The impact of irbesartan treatment on biomarkers of low-grade inflammation, endothelial dysfunction, growth factors, and advanced glycation end products (AGEs) during the Irbesartan in Patients with Type 2 Diabetes and Microalbuminuria (IRMA 2) study was evaluated. IRMA 2 was a 2-year multicenter, randomized, double-blind trial in patients comparing irbesartan (150 or 300 mg once daily) versus placebo. The primary end point was onset of overt nephropathy. A subgroup (n = 269, 68%) was analyzed for biomarkers at baseline and after 1 and 2 years. High-sensitivity C-reactive protein (hs-CRP), interleukin (IL)-6, fibrinogen, adhesion molecules, transforming growth factor-beta, and AGE peptides were assessed. Irbesartan treatment yielded significant changes in hs-CRP (based on generalized estimating equation regression coefficient) with a 5.4% decrease per year versus a 10% increase per year in the placebo group (P < 0.001). Fibrinogen decreased 0.059 g/l per year from baseline versus placebo's 0.059 g/l increase per year (P = 0.027). IL-6 showed a 1.8% increase per year compared with placebo's 6.5% increase per year (P = 0.005). Changes in IL-6 were associated with changes in albumin excretion (P = 0.04). There was no treatment effect on the other biomarkers. Irbesartan (300 mg once daily) reduces low-grade inflammation in this high-risk population, and this may reduce the risk of micro- and macrovascular disease.

Differential Effects of β-Blockers on Albuminuria in Patients With Type 2 Diabetes

Increases in the cardiovascular risk marker microalbuminuria are attenuated by blood pressure reduction using blockers of the renin-angiotensin system. Such changes in microalbuminuria have not been observed when β-blockers are used. A prespecified secondary end point of the Glycemic Effects in Diabetes Mellitus Carvedilol-Metoprolol Comparison in Hypertensives (GEMINI) trial was to examine the effects of different β-blockers on changes in albuminuria in the presence of renin-angiotensin system blockade. Participants with hypertension and type 2 diabetes were randomized to either metoprolol tartrate (n=737) or carvedilol (n=498) in blinded fashion after a washout period of all antihypertensive agents except for angiotensin-converting enzyme inhibitors or angiotensin receptor blockers. Blinded medication was titrated to achieve target blood pressure, with a-5 month follow-up period. The current analysis examined microalbuminuria, using spot urine albumin:creatinine, in participants who had values at screening and trial end. A greater reduction in microalbuminuria was observed for those randomized to carvedilol (−16.2%Δ; 95% confidence interval, −25.3, −5.9; P =0.003). Of those with normoalbuminuria at baseline, fewer progressed to microalbuminuria on carvedilol versus metoprolol (20 of 302 [6.6%] versus 48 of 431 [11.1%], respectively; P =0.03). Microalbuminuria development was not related to differences in blood pressure or achievement of blood pressure goal (68% carvedilol versus 67%, metoprolol). Presence of metabolic syndrome at baseline was the only independent predictor of worsening albuminuria throughout the study ( P =0.004). β-Blockers have differential effects on microalbuminuria in the presence of renin-angiotensin system blockade. These differences cannot be explained by effects on blood pressure or α1-antagonism but may relate to antioxidant properties of carvedilol.

Angiotensin-receptor blockade versus converting-enzyme inhibition in type 2 diabetes and nephropathy

BACKGROUND

Few studies have directly compared the renoprotective effects of angiotensin II-receptor blockers and angiotensin-converting-enzyme (ACE) inhibitors in persons with type 2 diabetes.

METHODS

In this prospective, multicenter, double-blind, five-year study, we randomly assigned 250 subjects with type 2 diabetes and early nephropathy to receive either the angiotensin II-receptor blocker telmisartan (80 mg daily, in 120 subjects) or the ACE inhibitor enalapril (20 mg daily, in 130 subjects). The primary end point was the change in the glomerular filtration rate (determined by measuring the plasma clearance of iohexol) between the baseline value and the last available value during the five-year treatment period. Secondary end points included the annual changes in the glomerular filtration rate, serum creatinine level, urinary albumin excretion, and blood pressure; the rates of end-stage renal disease and cardiovascular events; and the rate of death from all causes.

RESULTS

After five years, the change in the glomerular filtration rate was -17.5 ml per minute per 1.73 m2 (where the minus sign denotes a decrement) in the telmisartan-treated subjects, as compared with -15.0 ml per minute per 1.73 m2 in the enalapril-treated subjects; the treatment difference was thus -2.6 ml per minute per 1.73 m2 (95 percent confidence interval, -7.1 to 2.0 ml per minute per 1.73 m2)[corrected] The lower boundary of the confidence interval, in favor of enalapril, was greater than the predefined margin of -10.0 ml per minute per 1.73 m2, indicating that telmisartan was not inferior to enalapril. The effects of the two agents on the secondary end points were not significantly different after five years.

CONCLUSIONS

Telmisartan is not inferior to enalapril in providing long-term renoprotection in persons with type 2 diabetes. These findings do not necessarily apply to persons with more advanced nephropathy, but they support the clinical equivalence of angiotensin II-receptor blockers and ACE inhibitors in persons with conditions that place them at high risk for cardiovascular events.

Cost-effectiveness of early irbesartan treatment versus control (standard antihypertensive medications excluding ACE inhibitors, other angiotensin-2 receptor antagonists, and dihydropyridine calcium channel blockers) or late irbesartan treatment in patients with type 2 diabetes, hypertension, and renal disease

OBJECTIVE

The aim of this study was to determine the most cost-effective time point for initiation of irbesartan treatment in hypertensive patients with type 2 diabetes and renal disease.

RESEARCH DESIGN AND METHODS

This study was a Markov model-simulated progression from microalbuminuria to overt nephropathy, doubling of serum creatinine, end-stage renal disease, and death in hypertensive patients with type 2 diabetes. Two irbesartan strategies were created: early irbesartan 300 mg daily (initiated with microalbuminuria) and late irbesartan (initiated with overt nephropathy). These strategies were compared with control, which consisted of antihypertensive therapy with standard medications (excluding ACE inhibitors, other angiotensin-2 receptor antagonists, and dihydropyridine calcium channel blockers) with comparable blood pressure control, initiated at microalbuminuria. Transition probabilities were taken from the Irbesartan in Reduction of Microalbuminuria-2 study, Irbesartan in Diabetic Nephropathy Trial, and other published sources. Costs and life expectancy, discounted at 3% yearly, were projected over 25 years for 1,000 simulated patients using a third-party payer perspective in a U.S. setting.

RESULTS

Compared with control, early and late irbesartan treatment in 1,000 patients were projected to save (mean +/- SD) 11.9 +/- 3.3 million dollars and 3.3 +/- 2.7 million dollars, respectively. Early use of irbesartan added 1,550 +/- 270 undiscounted life-years (discounted 960 +/- 180), whereas late irbesartan added 71 +/- 40 life-years (discounted 48 +/- 27) in 1,000 patients. Early irbesartan treatment was superior under a wide-range of plausible assumptions.

CONCLUSIONS

Early irbesartan treatment was projected to improve life expectancy and reduce costs in hypertensive patients with type 2 diabetes and microalbuminuria. Later use of irbesartan in overt nephropathy is also superior to standard care, but irbesartan should be started earlier and continued long term.

Kidney function during and after withdrawal of long-term irbesartan treatment in patients with type 2 diabetes and microalbuminuria

OBJECTIVE

Irbesartan is renoprotective in patients with type 2 diabetes and microalbuminuria. Whether the observed reduction in microalbuminuria is reversible (hemodynamic) or persistent (glomerular structural/biochemical normalization) after prolonged antihypertensive treatment is unknown. Therefore, the present substudy of the Irbesartan in Patients with Type 2 Diabetes and Microalbuminuria Study (IRMA-2) investigated the reversibility of kidney function changes after withdrawal of 2 years' antihypertensive treatment.

RESEARCH DESIGN AND METHODS

The substudy included 133 hypertensive type 2 diabetic patients with persistent microalbuminuria in IRMA-2, randomized to double-masked treatment with either placebo, irbesartan 150 mg, or irbesartan 300 mg o.d. for 2 years. Arterial blood pressure, overnight urinary albumin excretion rate, and glomerular filtration rate (GFR) were determined repeatedly.

RESULTS

Baseline characteristics were similar in the placebo, irbesartan 150-mg, and irbesartan 300-mg groups. At the end of the study, mean arterial blood pressure (MABP) was similarly lowered to 105 +/- 2 (mean +/- SE), 103 +/- 2, and 102 +/- 2 mmHg, respectively (P < 0.05 versus baseline), and urinary albumin excretion rate reduced by 8% (-16 to 27) (NS), 34% (95% CI 8-53), and 60% (46-70) (P < 0.05). Rates of decline in GFR were 1.3 +/- 0.7, 1.2 +/- 0.7, and 1.0 +/- 0.8 ml. min(-1). 1.73 m(-2) per month, respectively, during the initial 3 months of the study and 0.3 +/- 0.1, 0.3 +/- 0.1, and 0.4 +/- 0.1 ml. min(-1). 1.73 m(-2) per month in the remaining study period. One month after withdrawal of all antihypertensive medication, MABP remained unchanged in the placebo group, 105 +/- 2 mmHg, but increased significantly in the irbesartan groups, to 109 +/- 2 and 108 +/- 2 mmHg, respectively. Compared with baseline, urinary albumin excretion rate was increased by 14% (-17 to 54) in the placebo group and by 11% (-26 to 65) in the irbesartan 150-mg group but was persistently reduced by 47% (24-73) in the irbesartan 300-mg group (P < 0.05). GFR levels increased to baseline values in the placebo group and approached initial levels in irbesartan groups.

CONCLUSIONS

Persistent reduction of microalbuminuria after withdrawal of all antihypertensive treatment suggests that high-dose irbesartan treatment confers long-term renoprotective effects.

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.

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.

Outcome studies in diabetic nephropathy

Outcome studies in diabetic nephropathy have focused on strategies to prevent progression of diabetic nephropathy, the leading cause of ESRD in the United States. Once diabetics develop overt nephropathy, prognosis is poor. Risk factors for diabetic nephropathy are discussed, and include hyperglycemia, hypertension, angiotensin II, proteinuria, dyslipidemia, smoking, and anemia. Major outcomes as well as outcome studies in diabetic nephropathy for patients with microalbuminuria and macroalbuminuria are reviewed. Furthermore, the role of therapy with angiotensin converting enzyme inhibitors, angiotensin II receptor blockers, calcium channel blockers, and mineralocorticoid receptor antagonists as well as selected combination therapy are discussed. Recommendations for therapy with ace inhibitors and angiotensin II receptor blockers are made based on this evidence.

Treatment of diabetic nephropathy in its early stages

Diabetic nephropathy is one of the most frequent causes of end-stage renal disease (ESRD), and, in recent years, the number of diabetic patients entering renal replacement therapy has dramatically increased. The magnitude of the problem has led to numerous efforts to identify preventive and therapeutic strategies. In normoalbuminuric patients, optimal glycemic control (HbA(1c) lower than 7.5%) plays a fundamental role in the primary prevention of ESRD [weighted mean relative risk reduction (RRR) approximately 37% for metabolic control versus trivial renoprotection for intensive anti-hypertensive therapy or ACE-inhibitors (ACE-I)]. In the microalbuminuric stage, strict glycemic control probably reduces the incidence of overt nephropathy (weighted mean RRR approximately 50%), while blood pressure levels below 130/80 mmHg are recommended according to the average blood pressure levels obtained in various studies. In normotensive patients, ACE-I markedly reduce the development of overt nephropathy almost regardless of blood pressure levels; in hypertensive patients, ACE-I are less clearly active (weighted mean RRR approximately 23% versus other drugs), whereas angiotensin-receptor blockers (ARB) appear strikingly renoprotective. Once overt proteinuria appears, it is uncertain whether glycemic control affects the progression of nephropathy. In type 1 diabetes, various anti-hypertensive treatments, mainly ACE-I, are effective in slowing down the progression of nephropathy; in type 2 diabetes, two recent studies demonstrate that ARB are superior to conventional therapy or calcium channel blockers (CCB). In clinical practice, pharmacological tools are not always used to the best benefit of the patients. Therefore, clinicians and patients need to be educated regarding the renoprotection of drugs inhibiting the renin-angiotensin system (RAS) and the overwhelming importance of achieving target blood pressure.

Appropriate drug therapy for improving outcomes in diabetic nephropathy

Diabetic nephropathy is the leading cause of end-stage kidney disease in the United States. The majority of these cases are attributed to those with type 2 diabetes. Elevated blood pressure, proteinuria, and increased activity of the renin-angiotensin-aldosterone system (RAAS) play a major role in the development and progression of chronic kidney disease attributed to diabetes mellitus. Moreover, drugs that inhibit angiotensin II synthesis or block the angiotensin II type I receptor lower blood pressure, reduce proteinuria, and improve outcomes in patients with chronic kidney disease caused by diabetes. This article highlights improvements in the current management of diabetic nephropathy afforded by agents that inhibit the RAAS, discusses their limitations, and considers novel strategies to prevent onset and progression of diabetic nephropathy. Current opinions concerning combination drug therapy with agents that block the RAAS at multiple sites, as well as combining calcium channel blockers with either angiotensin-converting enzyme inhibitors or angiotensin II receptor antagonists, are also discussed.

Antihypertensive treatment in patients with type-2 diabetes mellitus: what guidance from recent controlled randomized trials?

BACKGROUND

Patients with type-2 diabetes have a high prevalence of hypertension and show an elevated incidence of cardiovascular events and nephropathy.

OBJECTIVES

Recent randomized trials of antihypertensive therapy providing information about cardiovascular and renal risk in diabetes, blood pressure goals and best suitable drugs were reviewed.

FINDINGS

Evidence that association of type-2 diabetes with hypertension markedly increases cardiovascular and renal risk is incontrovertible: even blood pressure values in the high-normal range represent a more relevant risk than in non-diabetics. More versus less intensive blood pressure lowering or active versus placebo treatment can significantly prevent cardiovascular and renal events, with a particularly consistent reduction of proteinuria and microalbuminuria. Although several of the trials showing significant reduction of cardiovascular or renal risk achieved diastolic blood pressure (DBP) between 75 and 82 mmHg, systolic blood pressure (SBP) 140 mmHg was never achieved in trials showing cardiovascular benefits and SBP 130 mmHg was only achieved in two trials in normotensive subjects showing proteinuria reduction. The recommendation given by all major guidelines to lower SBP 130 mmHg appears to be difficult to comply with. Evidence of the superiority or inferiority of different drug classes (angiotensin-converting enzyme inhibitors, calcium antagonists, diuretics and beta-blockers) is rather vague, especially for cardiovascular protection. As to angiotensin-receptor antagonists, losartan has shown significant cardiovascular protection over a beta-blocker, and irbesartan, although not showing cardiovascular benefits over a calcium antagonist, was significantly better in retarding renal dysfunction and failure.

CONCLUSIONS

In most trials on hypertensive diabetics, the large majority of patients were on two, three and even four-drug therapy. Therefore, it appears reasonable that all effective and well tolerated antihypertensive agents can be used in association to achieve DBP 80 mmHg and, whenever possible, SBP 130 or 135 mmHg, with the regular inclusion of an angiotensin-receptor antagonist for its proven renoprotective action. Hopefully, better guidance will be provided by further trials.

Microalbuminuria in type 1 and type 2 diabetes mellitus: evidence with angiotensin converting enzyme inhibitors and angiotensin II receptor blockers for treating early and preventing clinical nephropathy

A cumulative incidence of diabetic nephropathy of 25% to 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 to 7 years after the onset of persistent proteinuria. The two main treatment strategies for prevention of diabetic nephropathy are improved glycemic control and blood pressure lowering, particularly using drugs blocking the renin-angiotensin system. 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 at high risk for developing diabetic nephropathy (eg, those with microalbuminuria) has been documented, applying angiotensin converting enzyme inhibitors and angiotensin II receptor blockade. The renoprotective effects of these drugs are independent of their beneficial reduction in blood pressure.

Rationale and design of diabetics exposed to telmisartan and enalapril (DETAIL) study

The DETAIL (diabetics exposed to telmisartan and enalapril) study will compare the long-term renal outcome of treatment with the angiotensin II receptor antagonist (ARA) telmisartan versus the angiotensin-converting enzyme (ACE) inhibitor enalapril in patients with mild-to-moderate hypertension and diabetic nephropathy. In short-term clinical studies, ACE inhibitors reduce microalbuminuria and, in the longer term, they are superior to conventional therapies in maintaining normal renal function. ARAs also appear to be renoprotective in diabetic animals. In this double-blind, parallel-group study, 252 patients with Type 2 diabetes and concurrent hypertension (mean seated systolic blood pressure < or = 180 mm Hg, on treatment seated diastolic blood pressure < or = 95 mm Hg) have been randomised to once-daily telmisartan 40 mg or enalapril 10 mg; doses are mandatorily titrated to 80 and 20 mg once daily, respectively, after 4 weeks. The primary endpoint will be the change from baseline in glomerular filtration rate (GFR) after 5 years of therapy, using the iohexol method and central laboratory analysis. The secondary endpoints to be evaluated will be: changes in GFR in relation to baseline after 1-4 years of therapy; percentage changes in albumin excretion rate after 1-5 years; and incidences of end-stage renal disease, cardiovascular events, all-cause mortality, and adverse events. The planned date for the completion of the study is 2005.

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.

The effect of irbesartan on the development of diabetic nephropathy in patients with type 2 diabetes

BACKGROUND

Microalbuminuria and hypertension are risk factors for diabetic nephropathy. Blockade of the renin-angiotensin system slows the progression to diabetic nephropathy in patients with type 1 diabetes, but similar data are lacking for hypertensive patients with type 2 diabetes. We evaluated the renoprotective effect of the angiotensin-II-receptor antagonist irbesartan in hypertensive patients with type 2 diabetes and microalbuminuria.

METHODS

A total of 590 hypertensive patients with type 2 diabetes and microalbuminuria were enrolled in this multinational, randomized, double-blind, placebo-controlled study of irbesartan, at a dose of either 150 mg daily or 300 mg daily, and were followed for two years. The primary outcome was the time to the onset of diabetic nephropathy, defined by persistent albuminuria in overnight specimens, with a urinary albumin excretion rate that was greater than 200 microg per minute and at least 30 percent higher than the base-line level.

RESULTS

The base-line characteristics in the three groups were similar. Ten of the 194 patients in the 300-mg group (5.2 percent) and 19 of the 195 patients in the 150-mg group (9.7 percent) reached the primary end point, as compared with 30 of the 201 patients in the placebo group (14.9 percent) (hazard ratios, 0.30 [95 percent confidence interval, 0.14 to 0.61; P< 0.001] and 0.61 [95 percent confidence interval, 0.34 to 1.08; P=0.081 for the two irbesartan groups, respectively). The average blood pressure during the course of the study was 144/83 mm Hg in the placebo group, 143/83 mm Hg in the 150-mg group, and 141/83 mm Hg in the 300-mg group (P=0.004 for the comparison of systolic blood pressure between the placebo group and the combined irbesartan groups). Serious adverse events were less frequent among the patients treated with irbesartan (P=0.02).

CONCLUSIONS

Irbesartan is renoprotective independently of its blood-pressure-lowering effect in patients with type 2 diabetes and microalbuminuria.

Baseline characteristics of the diabetic participants in the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT)

OBJECTIVE

Hypertension (HTN) is a major risk factor for cardiovascular disease (CVD) in the setting of diabetes. There is no consensus on how best to treat hypertension among those with diabetes. Here we describe the characteristics of a cohort of hypertensive adults with diabetes who are part of a large prospective blood pressure study. This study will help clarify the treatment of HTN in the setting of diabetes.

RESEARCH DESIGN AND METHODS

The Antihypertensive and Lipid-Lowering high-risk hypertensive participants, ages > or = 55 years, designed to determine whether the incidence of fatal and nonfatal coronary heart disease (CHD) and combined cardiovascular events (fatal and nonfatal CHD, revascularization surgery, angina pectoris, congestive heart failure, and stroke) differs between diuretic (chlorthalidone) treatment and three alternative antihypertensive therapies: a calcium channel blocker (amlodipine), an ACE inhibitor (lisinopril), and an alpha-adrenergic blocker (doxazosin). The planned follow-up is an average of 6 years, to be completed March 2002.

RESULTS

There are 15,297 diabetic individuals in the ALLHAT study (36.0% of the entire cohort). Of these individuals, 50.2% are male, 39.4% are African-American, and 17.7% are Hispanic. Demographic and laboratory characteristics of the cohort are similar to those of other studies of the U.S. elderly population with HTN. The sample size has 42 and 93% confidence, treatments for the two study outcomes.

CONCLUSIONS

The diabetic cohort in ALLHAT wil be able to provide valuable information about the treatment of hypertension in older diabetic patients at risk for incident CVD.

Long-term comparison of losartan and enalapril on kidney function in hypertensive type 2 diabetics with early nephropathy

BACKGROUND

The objectives of this study were to compare the effects of the angiotensin II receptor blocker, losartan, to those of the angiotensin-converting enzyme inhibitor, enalapril, on albuminuria and renal function in relationship to clinic and ambulatory blood pressure (ABP) in hypertensive type 2 diabetic subjects with early nephropathy. The tolerability of these agents and their effect on the metabolic profile were also evaluated.

METHODS

The study was a one-year prospective, double-blind trial with losartan and enalapril administered alone or in combination with hydrochlorothiazide and other antihypertensive agents. ABP and renal and biochemical parameters were measured at baseline and after 12, 28, and 52 weeks of active treatment. Ninety-two hypertensive type 2 diabetics with early nephropathy completed the study.

RESULTS

Both losartan and enalapril administered alone or in combination with other agents induced significant reductions in sitting clinic (P < 0.05) and ABP (P < 0.002) without a statistical difference between groups. Geometric means for urinary albumin excretion (UAE) decreased significantly (P < 0.001) in patients treated with losartan from 64. 1 to 41.5 microg/min and in those treated with enalapril from 73.9 to 33.5 microg/min after 52 weeks of therapy. A significant relationship (P < 0.05) between changes in systolic and diastolic ABP and the decrease in UAE at 52 weeks was seen in both groups. The decline in glomerular filtration rate (GFR) was stabilized at the end of therapy and was identical in both treatment groups. Treatment with enalapril was associated with a significantly higher incidence of cough (P = 0.006) and a rise in serum uric acid (P = 0.002) compared with losartan.

CONCLUSIONS

Our results indicate that a one-year course of antihypertensive therapy with either losartan or enalapril significantly reduces UAE in hypertensive type 2 diabetic patients with early nephropathy. The reduction in UAE with each treatment is similarly related to decrements in ABP. In addition, the rate of decline in GFR is similar in both treatment groups.

Are angiotensin-converting enzyme inhibitors the best treatment for hypertension in type 2 diabetes?

The influence of hypertension on the clinical course and complications of type 2 diabetes is well established. With a special focus on angiotensin-converting enzyme inhibitors, this paper will review recently published results of prospective studies addressing two important aspects: the degree of blood pressure control, and the choice of antihypertensive regimen, in the prevention of complications in hypertensive type 2 diabetic patients. None of the recent studies have shown worse outcomes in patients treated with angiotensin-converting enzyme inhibitor-based regimens compared with alternative treatments. Some studies have suggested that angiotensin-converting enzyme inhibitor-based antihypertensive regimens may be superior to alternative treatments in reducing the risk of micro- and macrovascular complications, whereas other studies found similar effects for beta-blockers or calcium antagonists. Several trials showed beneficial effects of angiotensin-converting enzyme inhibitors over calcium antagonists, and have raised concerns about the use of dihydropyridine calcium antagonists in these patients. However, it remains to be determined whether there should be more reserved use of calcium antagonists in such patients, in the light of more major trials showing the safety and efficacy of calcium antagonists in preventing cardiovascular and renal endpoints. The degree of reduction of blood pressure rather than the choice of a particular drug may be the most important factor. Studies focusing on renal endpoints suggest that angiotensin-converting enzyme inhibitors have a better antiproteinuric effect than other agents, but this phenomenon is not always reflected by a more beneficial effect of angiotensin-converting enzyme inhibitors on the decline in glomerular filtration rate. In many ways, the question of whether angiotensin-converting enzyme inhibitors are the best class of agent in these patients is academic. Angiotensin-converting enzyme inhibitors are sufficiently safe, and, according to recent evidence, equally or more effective than other classes of agents. Tight blood pressure control is usually achievable only with a combination of agents. On the basis of available evidence, it appears that angiotensin-converting enzyme inhibitors, together with a low-dose cardioselective beta-blocker and a diuretic, should be used in most hypertensive type 2 diabetes patients, with calcium antagonists serving as reserve drugs in case of insufficient blood pressure control.

Antihypertensive drugs and diabetic nephropathy

Diabetic nephropathy is the most common cause of end-stage renal disease in the United States. Hypertension is a major risk factor that predisposes individuals with diabetes to the development of renal disease and is very common in patients with diabetes. The benefit of blood pressure control on the rate of progression of diabetic nephropathy is being increasingly demonstrated in both type 1 and type 2 diabetic patients. Angiotensin converting enzyme inhibitors have proven renoprotective benefits in human studies, but the results of studies with calcium channel blockers are somewhat inconclusive. The other classes of antihypertensives also may have certain indications in the population of patients with diabetic nephropathy. In this paper we will critically review current strategies for the treatment of hypertension in patients with established diabetic nephropathy.

Renal disease and hypertension in non-insulin-dependent diabetes mellitus

Recent epidemiologic data demonstrate a dramatic increase in the incidence of end-stage renal disease (ESRD) in patients with non-insulin-dependent diabetes mellitus (NIDDM), thus dispelling the mistaken belief that renal prognosis is benign in NIDDM. Currently, the leading cause of ESRD in the United States, Japan, and in most industrialized Europe is NIDDM, accounting for nearly 90% of all cases of diabetes. In addition to profound economic costs, patients with NIDDM and diabetic nephropathy have a dramatically increased morbidity and premature mortality. NIDDM-related nephropathy varies widely among racial and ethnic groups, genders and lifestyles; and gender may interact with race to affect the disease progression. While the course of insulin-dependent diabetes mellitus (IDDM) progresses through well-defined stages, the natural history of NIDDM is less well characterized. NIDDM patients with coronary heart disease have a higher urinary albumin excretion rate at the time of diagnosis and follow-up. This greater risk may also be associated with hypertension and hyperlipidemia, and genes involved in blood pressure are obvious candidate genes for diabetic nephropathy. Hyperglycemia appears to be an important factor in the development of proteinuria in NIDDM, but its role and the influence of diet are not yet clear. Tobacco smoking can also be deleterious to the diabetic patient, and is also associated with disease progression. Maintaining euglycemia, stopping smoking and controlling blood pressure may prevent or slow the progression of NIDDM-related nephropathy and reduce extrarenal injury. Treatment recommendations include early screening for hyperlipidemia, appropriate exercise and a healthy diet. Cornerstones of management should also include: (1) educating the medical community and more widely disseminating data supporting the value of early treatment of microalbuminuria; (2) developing a comprehensive, multidisciplinary team approach that involves physicians, nurses, diabetes educators and behavioral therapists; and (3) intensifying research in this field.

Combination of enalapril and low-dose thiazide reduces normoalbuminuria in essential hypertension

OBJECTIVE

To examine the effect of the combination of enalapril with a very low dose of hydrochlorothiazide versus atenolol on urinary albumin excretion in normoalbuminuric patients with mild to moderate essential hypertension. A secondary objective was to compare the effects of the two regimens in patients with different levels of albuminuria.

DESIGN

A 12 weeks, randomized, double-blind, double-dummy, multicenter, comparative study with two parallel groups.

SETTING

General practices in Denmark and Finland.

PATIENTS

The subjects comprised 174 patients with mild to moderate essential hypertension, normal serum creatinine and no proteinuria.

INTERVENTIONS

Enalapril/hydrochlorothiazide (20/6 mg) daily or atenolol (50 mg) daily.

MAIN OUTCOME MEASURES

Urinary albumin: creatinine ratio and blood pressure.

RESULTS

At baseline, normoalbuminuria was found in 74 and 85 patients in the enalapril/hydrochlorothiazide and atenolol groups, respectively. Blood pressure was reduced similarly by both treatments. The ratio of urinary albumin to creatinine in normoalbuminuric patients was significantly reduced during treatment with enalapril/hydrochlorothiazide at 20/6 mg (from geometic mean x/divided by antilog SD of 0.53 x/divided by 1.77 to 0.47 x/divided by 1.58 mg/mmol, P=0.02) but was unchanged during atenolol treatment (0.55 x/divided by 1.74 and 0.58 x/divided by 1.87 mg/mmol). The difference between the two treatments was statistically significant (P=0.03) and was predominantly achieved through a reduction of albuminuria in the upper-normal range during enalapril/hydrochlorothiazide treatment.

CONCLUSIONS

Therapy with enalapril/hydrochlorothiazide at 20/6 mg and atenolol at 50 mg once daily reduced blood pressure similarly in patients with essential hypertension. Suppression of urinary albumin excretion within the normoalbuminuric range was observed during treatment with enalapril/hydrochlorothiazide at 20/6 mg.

Drug treatment of hypertension complicating diabetes mellitus

Hypertension and diabetes mellitus are both common conditions associated with a high morbidity and mortality. When the two conditions occur together, as they do in 50% of diabetic individuals, the result is a 7.2-fold increase in mortality. If hypertension occurs in association with diabetes mellitus and diabetic nephropathy, mortality rises to 37-fold above that of a healthy population. Despite the increase in incidence of nephropathy, cardiovascular disease remains the major cause of death in diabetic individuals. Therapy should therefore take into consideration the results of large, placebo-controlled trials which have shown reduction in cardiovascular morbidity and mortality as a result of active treatment. Although studies with the newer antihypertensive agents such as calcium antagonists and angiotensin converting enzyme (ACE) inhibitors are ongoing, only diuretics and beta-adrenoceptor antagonists have been clearly shown to reduce cardiovascular risk. Despite concerns regarding adverse metabolic effects and loss of hypoglycaemic awareness, beta-blockers and diuretics do have a role in the management of diabetic patients. While it is clear that ACE inhibitors reduce the progression of diabetic nephropathy, evidence suggests that diuretics may be just as effective. However, unlike diuretics or beta-blockers, ACE inhibitors have no proven benefit in the prevention of stroke of myocardial infarction. Despite the claims of metabolic neutrality made for many antihypertensive agents there appears to be no advantage in their use in the majority of hypertensive diabetic patients, except where there exist specific contraindications to established therapies.

Comparison of effects of quinapril and metoprolol on glycaemic control, serum lipids, blood pressure, albuminuria and quality of life in non-insulin-dependent diabetes mellitus patients with hypertension. Swedish Quinapril Group

OBJECTIVE

To compare the long-term effects of the angiotensin-converting enzyme (ACE)-inhibitor quinapril and the cardioselective beta-adrenergic blocking agent metoprolol on glycaemic control, with glycosylated haemoglobin (HbA1c) as the principal variable, in non-insulin-dependent diabetes mellitus (NIDDM) patients with hypertension.

DESIGN

A randomized, double-blind, double-dummy, multicentre study during 6 months preceded by a 4 week wash-out and a 3 week run-in placebo period. Quinapril (20 mg) and metoprolol (100 mg, conventional tablets) were given once daily. No change was made in the treatment of diabetes (diet and hypoglycaemic agents).

SUBJECTS

Seventy-two patients fulfilling the criteria were randomized and entered the double-blind period. Twelve patients did not complete the study. Sixty patients, 26 on quinapril and 34 on metoprolol, were available for the final analysis.

MAIN OUTCOME MEASURES

The effect was assessed by changes in HbA1c, the fasting serum glucose and the post-load serum glucose, C-peptide and insulin levels during the oral glucose tolerance test.

RESULTS

In the quinapril group, the fasting serum glucose, oral glucose tolerance and the C-peptide and insulin responses, determined as the incremental area under the curves (AUC), showed no change, but the mean HbA1c level increased from 6.2 +/- 1.1% to 6.5 +/- 1.3% (P < 0.05). In the metoprolol group, the rise in the mean level of HbA1c, from 6.3 +/- 1.0% to 6.8 +/- 1.3% (P < 0.01), tended to be more marked than after quinapril, although there was no significant difference between the increments. The mean fasting serum glucose showed an increase from 9.1 +/- 1.9 mM to 10.1 +/- 2.8 mM (P < 0.01) which correlated significantly with the duration of diabetes (P < 0.01) and the increase in fasting serum triglycerides (P < 0.001). Moreover, in the metoprolol group we found significant decreases in the oral glucose tolerance as well as C-peptide and insulin responses to the glucose load.

CONCLUSIONS

Treatment with quinapril for 6 months appears to have advantages over metoprolol in NIDDM patients with hypertension. Although treatment with quinapril or metoprolol over 6 months was concomitant with a rise in the HbA1c, increased fasting blood glucose, decreased oral glucose tolerance and decreased C-peptide and insulin responses to a glucose challenge were observed only in patients treated with metoprolol.

Pathogenesis, prevention, and treatment of diabetic nephropathy

It is likely that the pathophysiology of diabetic nephropathy involves an interaction of metabolic and haemodynamic factors. Relevant metabolic factors include glucose-dependent pathways such as advanced glycation, increased formation of polyols, and activation of the enzyme, protein kinase C. Specific inhibitors of the various pathways are now available, enabling investigation of the role of these processes in the pathogenesis of diabetic nephropathy and potentially to provide new therapeutic approaches for the prevention and treatment of diabetic nephropathy. Haemodynamic factors to consider include systemic hypertension, intraglomerular hypertension, and the role of vasoactive hormones, such as angiotensin II. The mainstay of therapy remains attaining optimum glycaemic control. Antihypertensive therapy has a major role in slowing the progression of diabetic nephropathy. Agents that interrupt the renin-angiotensin system such as angiotensin-converting enzyme inhibitors and angiotensin II receptor antagonists may be particularly useful as renoprotective agents in both the hypertensive and normotensive context.

Pharmacological treatment of diabetic patients with cardiovascular complications

Cardiovascular complications are frequently present in insulin-dependent (IDDM) and non-insulin dependent diabetes mellitus (NIDDM) patients and confer a very poor prognosis. In this overview we critically analyse the current literature with regard to the benefits and also the possible harms of the available pharmacological treatment strategies in these patients. To date, insulin is the only hypoglycaemic agent which has been proven both effective and safe in NIDDM patients with cardiovascular complications. Also, several trials indicate that treatment with oral hypoglycaemic agents may confer a substantial risk in such patients. Conventional antihypertensive treatment, including betablockers and diuretics, has been convincingly shown to reduce mortality and morbidity in diabetic nephropathy and in NIDDM patients. However, this may not be the case with newer antihypertensive agents, such as angiotensin-converting enzyme (ACE) inhibitors and calcium channel blockers. Likewise, convincing evidence is lacking that these newer antihypertensive agents provide meaningful clinical benefit when compared to the conventional treatment regarding slower progression of diabetic nephropathy or their impact on lipid and glucose metabolism. Cholesterol lowering therapy with statins and aspirin treatment have also been repeatedly shown to improve the prognosis of diabetic patients with coronary heart disease.

Therapeutic challenges in the obese diabetic patient with hypertension

Obesity, diabetes mellitus, and hypertension are common and interrelated medical problems in Westernized, industrialized societies. These medical conditions are associated with an increased risk of cardiovascular disease and are more prevalent among minorities, such as African-American and Hispanic populations. The associated cardiovascular risks of these problems are more thoroughly addressed in another review in this supplement. Obesity markedly enhances the development of type II diabetes. Moreover, it enhances the cardiovascular risk associated with other risk factors, such as hypertension and dyslipidemia. Weight reduction in association with an aerobic exercise program improves metabolic abnormalities and reduces blood pressure in individuals with diabetes and hypertension. Frequently, however, pharmacologic treatment is required to lower blood pressure. Individual therapy with an angiotensin-converting enzyme (ACE) inhibitor is preferred initially in these individuals, with the addition of either a low dose diuretic or a nondihydropyridine calcium antagonist if additional blood pressure reduction is required. These additive agents are recommended, since each has been shown individually to reduce cardiovascular morbidity and to preserve renal function among diabetic patients. Other issues, such as aggressive therapy of lipids and adequate glycemic control, are also important strategies for reducing cardiovascular and renal morbidity and mortality in this very high-risk population.

Microalbuminuria in type II diabetes

OBJECTIVE

To emphasize the prognostic significance of microalbuminuria in patients with type II diabetes and to summarize interventional studies in patients with non-insulin-dependent diabetes mellitus and nephropathy.

METHODS

The definition of microalbuminuria is reviewed, the implications of its presence are discussed, and published trials of medical intervention to treat proteinuria in patients with type II diabetes are outlined.

RESULTS

Microalbuminuria--defined as the presence of 30 to 300 mg of protein in a 24-hour urine specimen or a urinary albumin excretion rate of 20 to 200 mg/min--is frequently present in patients with non-insulin-dependent diabetes mellitus. It has been shown to be an independent cardiovascular risk factor as well as a predictor for the eventual development of renal failure. Intervention trials indicate that treatment with "tight" blood glucose control and antihypertensive agents, especially angiotensin-converting enzyme inhibitors, may be beneficial in reversing early proteinuria or at least in preventing the progression to renal failure.

CONCLUSION

The presence of microalbuminuria in patients with type II diabetes mellitus is associated with premature death from cardiovascular disease and the development of renal failure. Thus, aggressive therapy should be instituted.