Effects of an ACE inhibitor/calcium antagonist combination on proteinuria in diabetic nephropathy

Verapamil revisited: a transition in novel drug delivery systems and outcomes

Verapamil, the oldest calcium-channel blocker, is now being rediscovered and reevaluated in the light of new novel drug delivery systems and new evidence-based trials. Verapamil, a phenylalkylamine, is useful in the treatment of hypertension, stable angina, and narrow QRS supraventricular arrhythmias. This calcium antagonist is effective in both young and old, and both black and white hypertensive patients, and is free of metabolic side effects. Verapamil has a well-documented history as an effective antianginal agent when directly compared with a beta-blocker, and is more effective in reducing myocardial ischemia compared with amlodipine monotherapy. Because of the short half-life of verapamil, drug delivery systems are used to prolong the duration of action. Novel drug delivery systems using encapsulated beads or a modified osmotic pump have been designed to be taken at nighttime to provide maximal blood pressure reduction in the early morning hours and effective 24-hour blood pressure control, and to avoid excessive blood pressure reduction during sleep. The Verapamil in Hypertension and Atherosclerosis Study has documented equivalent effectiveness of verapamil compared with chlorthalidone, but showed superior plaque regression and reduced events in subjects with the greatest plaques with verapamil treatment. The Angina Prognosis Study in Stockholm, comparing verapamil and metoprolol for stable angina, found no difference in total cardiovascular mortality or combined cardiovascular events. Other large ongoing randomized, multicenter trials, including Controlled-Onset Verapamil Investigation of Cardiovascular Endpoints and the International Verapamil-Trandolapril Study, will expand our knowledge of the role of verapamil in the treatment of hypertension.

ACEI/ATRA therapy decreases proteinuria by improving glomerular permselectivity in IgA nephritis

BACKGROUND

It has been postulated that angiotensin-converting enzyme inhibitor/angiotensin receptor antagonist (ACEI/ATRA) may decrease proteinuria in patients with glomerulonephritis by its action on the glomerular basement membrane. We therefore studied the relationship between the response of patients with IgA nephritis (IgAN) to ACEI/ATRA therapy by decreasing proteinuria and its effect on the selectivity index (SI) in these patients.

METHODS

Forty-one patients with biopsy-proven IgAN entered a control trial, with 21 in the treatment group and 20 in the control group. The entry criteria included proteinuria of 1 g or more and/or renal impairment. Patients in the treatment group received ACEI/ATRA or both with three monthly increases in dosage. In the control group, hypertension was treated with atenolol, hydrallazine, or methyldopa. The following tests were performed at three monthly intervals: serum creatinine, total urinary protein, SI, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and low molecular weight (LMW) proteinuria.

RESULTS

After a mean duration of therapy of 13 +/- 5 months, in the treatment group, there was no significant change in serum creatinine, proteinuria, or SI, but in the control group, serum creatinine deteriorated from 1.8 +/- 0.8 to 2.3 +/- 1.1 mg/dL (P < 0.05). Among the 21 patients in the treatment group, 10 responded to ACEI/ATRA therapy determined as a decrease in proteinuria by 30% (responders), and the other 11 did not respond (nonresponders). Among the responders, SI improved from a mean of 0.26 +/- 0.07 to 0.18 +/- 0. 07 (P < 0.001), indicating a tendency toward selective proteinuria. This was associated with an improvement in serum creatinine from mean 1.7 +/- 0.6 to 1.5 +/- 0.6 mg/dL (P < 0.02) and a decrease in proteinuria from a mean of 2.3 +/- 1.1 to 0.7 +/- 0.5 g/day (P < 0. 001). After treatment, proteinuria in the treatment group (1.8 +/- 1. 6 g/day) was significantly less than in the control group (2.9 +/- 1. 8 g/day, P < 0.05). The post-treatment SI in the responder group (0. 18 +/- 0.07) was better than that of the nonresponder group (0.33 +/- 0.11, P < 0.002). Eight out of 21 patients in the treatment group who had documented renal impairment had improved renal function compared with two in the control group (chi2 = 4.4, P < 0. 05). Of the eight patients in the treatment group who improved their renal function, three normalized their renal function compared with one from the control group.

CONCLUSION

Our data suggest that ACEI/ATRA therapy may be beneficial in patients with IgAN with renal impairment and nonselective proteinuria, as such patients may respond to therapy with improvement in protein selectivity, decrease in proteinuria, and improvement in renal function. ACEI/ATRA therapy probably modifies pore size distribution by reducing the radius of large unselective pores, causing the shunt pathway to become less pronounced, resulting in less leakage of protein into the urine.

Renal protective potential of antihypertensive drugs

The objective of this review is to discuss recent experimental and clinical data concerning the effectiveness of antihypertensive drugs in preventing or delaying renal changes caused by diabetes mellitus and hypertension and to examine possible future developments. A brief description of the mechanisms involved in the development of renal failure in diabetes and hypertension is included. Evidence is presented to show that in addition to renoprotection offered by reduction in arterial pressure, some antihypertensive agents may give more nephroprotection. This added renoprotective potential of antihypertensive agents, which are either already in use or are being developed, is discussed. The nephroprotective action of conventional antihypertensive drugs, such as beta-blockers, calcium antagonists and angiotensin-converting enzyme inhibitors is briefly reviewed. It is noted that several studies indicate that angiotensin-converting enzyme inhibitors may be more effective in preventing or retarding renal failure than other conventional drugs. The renoprotective potential of newly developed agents, such as angiotensin II Type 1 receptor antagonists, vasopeptidase inhibitors and endothelin receptor antagonists is also examined. Emphasis is placed on a possible superior renoprotective effect of combination therapy over monotherapy.

Therapeutic potential of ACE inhibitors for the treatment of hypertension in Type 2 diabetes

Type 2 diabetes mellitus is associated with hypertension. If untreated, hypertension has a major impact on the clinical course of Type 2 diabetes and its vascular complications. In this review, we discuss rationale for the use of ACE inhibitors (ACEI) in hypertensive Type 2 diabetic patients and compare those theoretical assumptions with results of recent major clinical trials. Furthermore, possible directions for future clinical and experimental research are outlined. The RAS and its effector angiotensin II are important players in a number of cardiovascular and renal disorders. Recent evidence suggests that RAS and factors functionally linked to RAS are activated in Type 2 diabetes. Therefore, there is a theoretical basis for the use of ACEI in the treatment of hypertension in diabetic patients. Some recent studies reported superior outcome in patients treated with ACEI-based antihypertensive regimens compared with non-ACEI based treatments in reducing the risk of macrovascular disease (CAPPP, FACET, ABCD) or both micro- and macrovascular complications in Type 2 diabetes (HOPE). However, at least two of the large prospective studies discussed in this review (UKPDS 38, HOT), supported by results from previously published SHEP study, have recently suggested that the degree of reduction of blood pressure, rather than the choice of a particular class of antihypertensive agent, is associated with decreased risk of cardiovascular events. Studies focusing on renal end-points suggest that ACEI have a superior antiproteinuric effect than the other agents. However, whether ACEI are more nephroprotective, as assessed by the rate of decline in renal function, still remains to be elucidated. Despite promising results from recent trials, large numbers of patients progress despite ACEI treatment. Incomplete inhibition of the RAS may underlie this phenomenon. Treatment strategies that could enhance the degree of RAS inhibition represent one possible direction for clinical research in the near future. However, it is unlikely that the course of such a complex syndrome as Type 2 diabetes could be dramatically changed by just one class of antihypertensive agents. This goal is more likely to be achieved by multifactorial intervention, reflecting the complexity of metabolic syndrome. ACEI should be viewed as an important, but not the only, part of this complex approach.

Efficacy and safety of a new long-acting drug combination, trandolapril/verapamil as compared to monotherapy in primary hypertension. Swedish TARKA trialists

OBJECTIVE

To evaluate the clinical efficacy and safety of a new antihypertensive drug combination of trandolapril/verapamil compared to monotherapy with verapamil or trandolapril, in patients with mild to moderate primary hypertension.

DESIGN

A multicentre, prospective, randomized, double-blind, controlled cross-over study with specific statistical considerations.

SETTINGS

Eighteen primary health care centres and out-patient hospital clinics in Sweden.

PATIENTS

Two hundred and twenty-six outpatients with uncomplicated primary hypertension with a baseline sitting diastolic blood pressure (BP) between 95 and 115 mmHg.

INTERVENTIONS

After a 4-week placebo period, patients were randomized to treatment for 8 weeks with trandolapril/verapamil (2 mg/180 mg) or each drug alone (verapamil 240 mg, trandolapril 2 mg) for 8 weeks.

MAIN OUTCOME MEASURES

Treatment responses (blood pressure (BP) fall and rate pressure product) to the three regimens with statistical comparison and also in relation to plasma concentrations of active renin (AR). Adverse events and safety were also evaluated.

RESULTS

The mean BP fall was significantly greater with the combination (20/15 mmHg), p < 0.00054, as compared to both trandolapril (14/11 mmHg) or verapamil (13/11) mmHg. The difference between verapamil and trandolapril was not significant. Rate pressure product decreased significantly more on the combination, p < 0.001, than on trandolapril or verapamil alone. Treatment response to trandolapril was positively correlated to initial AR (r = 0.30-0.43). All treatments were well tolerated and safe.

CONCLUSIONS

The new fixed drug combination trandolapril/verapamil was superior to monotherapy with either of these drugs alone regarding reduction of both BP and rate pressure product. This combination can be safely and effectively used for the treatment of mild to moderate primary hypertension.

Urinary excretion of podocytes in patients with diabetic nephropathy

BACKGROUND

Detection of podocytes in the urinary sediments of children with glomerulonephritis has been shown to indicate severe injury to the podocytes. The aim of the present study was to determine whether podocytes are present in the urine sediments of adult patients with diabetes with and without nephropathy and whether trandolapril is effective for podocyte injury.

METHODS

Fifty diabetic patients (10 with normoalbuminuria, 15 with microalbuminuria, 15 with macroalbuminuria and 10 with chronic renal failure) and 10 healthy controls were studied. Urinary podocytes were examined by immunofluorescence using monoclonal antibodies against podocalyxin, which is present on the surface of podocytes. In addition, we studied plasma metalloproteinase (MMP)-9 concentrations in all patients.

RESULTS

Urinary podocytes were absent in healthy controls, diabetic patients with normoalbuminuria and diabetic patients with chronic renal failure. Podocytes were detected in the urine of eight diabetic patients with microalbuminuria (53%) and of 12 patients with macroalbuminuria (80%). The number of podocytes in the urine of patients with macroalbuminuria was significantly greater than in patients with microalbuminuria (P:<0.01). However, there was no relationship between urinary albumin excretion and urinary podocytes. In addition, plasma MMP-9 concentrations were significantly correlated with the number of urinary podocytes (P:<0.01). Twelve diabetic patients with macroalbuminuria and eight patients with microalbuminuria who had urinary podocytes were treated with the angiotensin-converting enzyme inhibitor trandolapril. Urinary albumin excretion, the number of podocytes and plasma MMP-9 concentrations were reduced by the trandolapril treatment.

CONCLUSIONS

Podocytes in the urine may be a useful marker of disease activity in diabetic nephropathy. Trandolapril may be effective for podocyte injury.

Preserving renal function in adults with hypertension and diabetes: a consensus approach. National Kidney Foundation Hypertension and Diabetes Executive Committees Working Group

Over 11 million Americans have both diabetes and hypertension-comorbid diseases that strongly predispose people to both renal as well as cardiovascular (CV) injury. Hypertension substantially contributes to CV morbidity and mortality in people with diabetes. Diabetes is the most common cause of end-stage renal disease in the United States. Furthermore, hypertension and diabetes are particularly prevalent in certain populations, such as African-Americans and Native Americans. Since the 1994 Working Group Report on Hypertension and Diabetes, a large body of clinical trial data has affirmed the original blood pressure goal of less than 130/85 mmHg recommended to preserve renal function and reduce CV events in people with hypertension and diabetes. Data that are more recent have emerged, however, to support an even lower diastolic blood pressure goal, ie, 80 mmHg, in order to optimally preserve renal function and reduce CV events in people with diabetic nephropathy. A review of clinical trials indicates that more than 65% of people with diabetes and hypertension will require two or more different antihypertensive medications to achieve the new suggested target blood pressure of 130/80 mmHg. The purpose of this report is to update the previous recommendations with a focus on level of blood pressure control, proteinuria reduction, and therapeutic approaches to achieve these goals. We provide an evidence-based approach, integrating data from the major clinical trials that were designed as randomized prospective, long-term studies that had as a primary endpoint either progression of diabetic nephropathy or reduction in CV events. This report also addresses socioeconomic and cultural barriers that hinder achievement of blood pressure goals. Lastly, the report discusses approaches to resolve cultural barriers, both physician- and patient-derived, that interfere with achievement of lower blood pressure goals.

Effect of antihypertensive therapy on renal injury in type 2 diabetic rats with hypertension

In a previous study, we demonstrated that doxazosin (DZN), an alpha(1)-adrenergic blocker, prevented proteinuria in streptozotocin diabetic rats. In this study, we investigated whether DZN would lower established proteinuria by improving glomerular sclerosis in spontaneously hypertensive corpulent rats with type 2 diabetes mellitus. DZN treatment was compared with treatment with angiotensin-converting enzyme inhibitor, lisinopril (LIS) alone, and DZN in combination with LIS. Combination therapy was used to examine any additive effect of either drug alone in the reduction of proteinuria and glomerular sclerosis. Both male and female rats age 6 months with established proteinuria were used. The rats were allocated randomly to 1 of 4 groups: untreated, DZN treated, LIS treated, or a combination of DZN and LIS treatment. Drug treatment was continued for 16 weeks. The results show that (1) either drug alone or in combination significantly lowered systolic blood pressure; (2) DZN, LIS, or combination therapy reduced albuminuria at 16 weeks of treatment from baseline by 38.61+/-5.77%, 30.70+/-4. 21%, and 42.17+/-4.77% (mean+/-SE), respectively. No difference in albuminuria was observed among the 3 groups of rats; (3) the fractional mesangial area, which was 20.55+/-3.77% in untreated rats, was significantly reduced to 11.18+/-1.32% in DZN-treated rats, with a further reduction to 8.72+/-0.64% in LIS-treated rats and to 3.48+/-0.35% in rats treated with DZN+LIS; and (4) DZN but not LIS significantly improved plasma glucose levels in spontaneously hypertensive corpulent rats (untreated 21.06+/-0.97 mmol/L versus DZN treated 15.81+/-0.93 mmol/L or DZN+LIS treated 17.38+/-1.10 mmol/L; P<0.025 to 0.005). Thus, the data suggest that 16-week treatment with either DZN or LIS improves established proteinuria and glomerular sclerosis, but combination therapy is superior to either DZN or LIS alone in preventing glomerular sclerosis in type 2 diabetic rats with hypertension.

Effect of nitrendipine and nisoldipine on renal structure and function in long-term experimental diabetes in rats

This study investigates the efficacy of late intervention with the calcium channel blockers (CCBs) nitrendipine and nisoldipine in preventing development of albuminuria and glomerular hypertrophy in experimental diabetes. Streptozotocin (STZ)-induced diabetic rats were treated with nitrendipine or nisoldipine for 6 weeks after 3 or 6 months of untreated diabetes. The CCBs were administered in the fodder in a concentration of 250 mg/kg. After 3 months of untreated diabetes, nitrendipine treatment for 6 weeks significantly reduced urinary albumin excretion (UAE; P < 0.05) and glomerular hypertrophy. Nitrendipine also prevented an increase in systemic blood pressure compared with untreated diabetes. Nisoldipine showed no significant effect on UAE or glomerular hypertrophy despite systemic blood pressures similar to those of the diabetic nitrendipine-treated group. After 6 months of untreated diabetes, treatment with nitrendipine or nisoldipine for 6 weeks did not show effects on UAE, glomerular hypertrophy, or systemic blood pressure. No effect was found on renal growth in the treatment groups, and neither nitrendipine nor nisoldipine had any effect on body weight, blood glucose level, or food intake.

Progressive renal insufficiency. Office strategies to prevent or slow progression of kidney disease

Prevention of chronic renal failure should be a primary healthcare goal in the new millennium. Better control of blood pressure, blood glucose, and lipid levels shows promise for slowing and perhaps even preventing renal dysfunction. Protein-sparing diets also may prove to be important. While it is not yet known whether combining interventions to treat each of these factors will have additive or synergistic effects, it seems prudent to approach these problems aggressively.

Hypertension in patients with diabetes. Strategies for drug therapy to reduce complications

Hypertension in diabetic patients must be treated aggressively if patients are to benefit from reduced risk of morbidity and mortality. Diabetes itself must be diagnosed promptly, particularly in at-risk patients, so appropriate lifestyle modifications can be made at the earliest opportunity. Although this may reduce or delay onset of hypertension, antihypertensive drug treatment should be initiated in the diabetic patient with even high-normal blood pressure. Traditional approaches to management of hypertension are inappropriate for most patients with diabetes. While ACE inhibitors, calcium antagonists, angiotensin II receptor blockers, beta blockers, and low-dose diuretics, alone or in combination, all currently have roles in hypertension management, the outcomes of studies now under way may clarify some still unanswered questions about the dangerous combination of high blood pressure and diabetes.

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.

The fixed combination of verapamil SR/trandolapril

Fixed verapamil SR/trandolapril combinations 180/1 mg and 180/2 mg (Tarka, Knoll AG) have a significantly superior antihypertensive effect compared to equal dosages of either agent alone. Verapamil SR/trandolapril 180/2 mg combination produces the best dose-response ratio of different dose combinations of these two drugs. Combination therapy has the most pronounced effect on blunting the early morning rise in blood pressure. Thus, verapamil SR/trandolapril combination therapy may be an appropriate treatment option in patients with moderate essential hypertension, particularly in those who have a tendency toward the early morning rise in blood pressure. The adverse effect profile of the fixed combination of verapamil SR/trandolapril includes the typical side effects of its monocompounds. The fixed combination of verapamil SR/trandolapril is also effective and safe in the treatment of hypertension in the elderly. The fixed low-dose combination therapy with verapamil SR/trandolapril 180/2 mg is a suitable treatment option for patients with moderate essential hypertension and Type 2 diabetes mellitus, because it improves parameters of carbohydrate metabolism and uricaemia and does not alter the lipid profile. The insulin-sensitising effect of angiotensin converting enzyme (ACE) inhibitor monotherapy with its theoretical risk of hypoglycaemia is completely neutralised in the combination with verapamil SR. Comparative studies have shown that the low-dose combination of verapamil SR/trandolapril may be a suitable alternative to combinations containing a thiazide diuretic or a beta-blocking agent for the long-term management of hypertensive patients for whom combination therapy is indicated. The combination of an ACE inhibitor with a non-dihydropyridine calcium channel blocker reduces proteinuria to a greater extent than either agent alone. A combination of an ACE inhibitor and a calcium channel blocker may provide additional benefit in inducing the regression of left ventricular hypertrophy. Combination therapy leads to a significant increase in left ventricular ejection fraction, improvement of wall motion index and increases exercise duration time in patients with coronary heart disease and left heart failure. It also improves the ratio of exercise to rest rate-pressure product and decreases the number of angina attacks. These findings support the hypothesis that the combination of verapamil and trandolapril might be useful in patients with attenuated left ventricular function and angina pectoris. Thus, Tarka is an effective and well-tolerated antihypertensive agent with a good safety profile and positive metabolic effects.

Diabetes in the elderly population

Type 2 diabetes mellitus has emerged as an important condition of older patients in which both microvascular and macrovascular complications are a common cause of morbidity and mortality. In contrast to type 1 diabetes mellitus, this endocrinopathy is clustered in minority populations and has both strong genetic and environmental factors that influence disease manifestation. A number of physiological alterations of glucose metabolism including hepatic overproduction of glucose, and reduced glucose utilization by peripheral tissues as a result of insulin resistance contribute to the development of the metabolic manifestations of this disease. Ultimately, pancreatic failure and reduced insulin secretion lead to hyperglycemia and the diabetic state. Frequently, many of these metabolic manifestations, or what has been termed Syndrome X, antecede the development of overt diabetes by many years. This syndrome is manifest clinically by such cardiovascular risk factors as hypertension, dyslipidemia, and coagulation abnormalities. This abnormal metabolic milieu contributes to the high prevalence of macrovascular complications including coronary artery disease as well as more generalized atherosclerosis. Microvascular complications have only more recently been recognized as an important and frequent complication of type 2 diabetes. Among the elderly and minority populations, this has become the single most important cause of end-stage renal failure that necessitates renal replacement therapies. The outcome for these patients on hemodialysis, the modality most frequently selected, is poor, with the majority of these patients dying of cardiovascular causes. Unfortunately, interventional strategies to reduce or prevent the microvascular and macrovascular complications have only recently received the needed attention and will require considerable effort and resources to improve the clinical outcomes and life expectancies for these patients.

Calcium-channel blockers and the progression of renal disease

Effective blood pressure (BP) reduction is now generally recognized as a clinically proven strategy to retard the seemingly inexorable downhill progression of patients with diabetic and nondiabetic chronic renal disease. Although calcium-channel blockers (CCBs) are effective antihypertensive agents, the available experimental and clinical data are quite contradictory as to whether BP reduction achieved with CCBs provides the expected renoprotection. Blockade of the "L" type, voltage-gated Ca channels that mediate the BP reduction also concurrently impairs renal autoregulatory responses of the preglomerular vasculature. Because these renal autoregulatory resistance changes provide the primary protection against the transmission of systemic hypertension to the renal microvasculature, the adverse effects of CCBs on renal autoregulation counteract the beneficial effects on BP reduction. The degree of renoprotection achieved, therefore, depends on the balance between these two opposing effects. The data also indicate that there are probably important and clinically relevant differences between the classes of CCBs, with the dihydropyridine (DHP) CCBs most likely to have consistent deleterious effects on renal autoregulation. However, the available data also indicate that the adverse effects of DHP CCBs are not likely to be observed if BP is lowered well into the normotensive range, possibly through the use of combination therapies. Even when used as adjunctive therapy, close monitoring may be advisable to ensure BP normalization and the absence of any untoward effects on proteinuria and renal function.

The case for combining angiotensin-converting enzyme inhibitors and calcium-channel blockers

Tight blood pressure control among diabetic and nondiabetic patients with hypertension is perhaps the single most effective intervention used to delay progression to end-stage renal disease (ESRD). The renoprotective actions of angiotensin-converting enzyme (ACE) inhibitors in patients with diabetic and hypertensive nephropathy is well established. Drugs of this class fairly uniformly reduce glomerulosclerosis, delay the deterioration in renal function, and improve proteinuria, a predictive surrogate marker for renal injury. Calcium- channel blockers (CCBs) in the phenylalkylamine (verapamil) and benzothiazepine (diltiazem) classes also improve proteinuria and delay the progression of renal disease in diabetic and nondiabetic hypertensive nephropathy beyond that attributable to blood pressure control. The short-acting dihydropyridine CCBs worsen proteinuria and accelerate renal injury in both animal models and humans with hypertension or diabetes. A very limited number of studies in animals or humans with hypertension or diabetes have demonstrated at least an additive renoprotective effect when the combination of ACE inhibitors and nondihydropyridine CCBs has been compared with each agent administered as monotherapy. Because patients with impaired renal function and either hypertension or diabetes appear to benefit from aggressive blood pressure reduction, many of these patients will require two or more drugs to achieve the currently recommended blood pressure goals. Combinations of ACE inhibitor and CCB are attractive because they may provide better blood pressure control, appear to be better tolerated with fewer side effects than either drug alone, and may exert a greater renoprotective effect in patients at risk for renal failure than either an ACE inhibitor or a CCB.

Diabetic nephropathy

Renal involvement is one of the major microvascular complications of both type 1 and type 2 diabetes mellitus. Diabetic nephropathy is the major cause of end-stage renal failure in most Western nations and is associated with increased morbidity and mortality as compared to other causes of renal disease. The pathogenesis of renal involvement in diabetes is presumed to be the result of the interplay of metabolic and hemodynamic factors. Significant advances in the prevention and treatment of progression of diabetic nephropathy have been achieved with intensive glycemic control and the treatment of elevated blood pressure. Patients with diabetes should thus be screened regularly for the appearance of any of the risk factors for renal or other complications and treated intensively according to established guidelines for control of hyperglycemia and hypertension. Ancillary therapeutic measures include treatment of hyperlipidemia, low-protein diet, and the cessation of smoking.