Effect of the angiotensin-converting-enzyme inhibitor benazepril on the progression of chronic renal insufficiency. The Angiotensin-Converting-Enzyme Inhibition in Progressive Renal Insufficiency Study Group

Novel therapy of focal glomerulosclerosis with mycophenolate and angiotensin blockade

Steroid-resistant nephrotic syndrome of childhood poses a dilemma in attempting to balance toxicity of medications against long-term prognosis. This report presents our preliminary experience with the novel use of combined mycophenolate mofetil (MMF) and angiotensin blockade (AB) in the treatment of nine children and young adults with focal glomerulosclerosis (FSGS). All patients were steroid resistant and had failed conventional treatment regimens. Prior to the initiation of the MMF-AB protocol, the patients were pre-treated with weekly intravenous methylprednisolone (MP) (15 mg/kg per week) for 4-8 weeks. Angiotensin-converting-enzyme inhibitors and/or angiotensin receptor blockers were begun when intravascular volume was restored. MMF was given at a dose of 250-500 mg/m(2) per day. Proteinuria, as measured by urine protein/creatinine ratios (Up/c), decreased by 43% following MP ( P<0.05). After 6 months of MMF-AB protocol, the Up/c was 72% below baseline ( P<0.01). This level was maintained for a minimum of 24 months of observation. Similarly, hyperlipidemia, as measured by total cholesterol and triglycerides, improved significantly with treatment (536+/-163 to 265+/-70 mg/dl, 447+/-168 to 230+/-92 mg/dl, respectively, P<0.01). Our data support the use of MMF and AB for treatment of steroid-resistant FSGS when other conventional treatments have failed and/or induced toxicity.

Design and statistical aspects of the African American Study of Kidney Disease and Hypertension (AASK)

The African American Study of Kidney Disease and Hypertension (AASK) is a multicenter randomized clinical trial designed to test the effectiveness of three anti-hypertensive drug regimens and two levels of BP control on the progression of hypertensive kidney disease. Participants include African-American men and women aged 18 to 70 yr who have hypertensive kidney disease and GFR between 20 and 65 ml/min per 1.73 m(2). The three anti-hypertensive drug regimens include an angiotensin converting enzyme inhibitor (ramipril), a dihydropyridine calcium channel blocker (amlodipine) or a beta-blocker (metoprolol) as initial therapy. The BP control levels are a lower goal (mean arterial pressure, Collapse

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MESH Headings

• Adolescent
• Adrenergic beta-Antagonists/administration & dosage
• Adult
• Black or African American/statistics & numerical data
• Aged
• Angiotensin-Converting Enzyme Inhibitors/administration & dosage
• Antihypertensive Agents/administration & dosage
• Calcium Channel Blockers/administration & dosage
• Dose-Response Relationship, Drug
• Drug Administration Schedule
• Drug Therapy, Combination
• Female
• Follow-Up Studies
• Humans
• Hypertension/complications
• Hypertension/diagnosis
• Hypertension/drug therapy
• Kidney Failure, Chronic/complications
• Kidney Failure, Chronic/diagnosis
• Kidney Failure, Chronic/therapy
• Male
• Middle Aged
• Pilot Projects
• Risk Assessment
• Treatment Outcome
• United States

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Grants

• U01 DK048643 NIDDK NIH HHS
• RR11145 NCRR NIH HHS
• U01 DK048648 NIDDK NIH HHS
• RR-00080 NCRR NIH HHS
• M01 RR000071 NCRR NIH HHS
• DK 2818 NIDDK NIH HHS
• M01 RR000052 NCRR NIH HHS
• M01 RR000032 NCRR NIH HHS
• K24 DK002818 NIDDK NIH HHS
• RR11104 NCRR NIH HHS
• RR-00071 NCRR NIH HHS
• P20 RR011104 NCRR NIH HHS
• P20 RR011145 NCRR NIH HHS
• U01 DK045381 NIDDK NIH HHS
• RR00827 NCRR NIH HHS
• U01 DK045386 NIDDK NIH HHS
• RR00052 NCRR NIH HHS
• M01 RR000827 NCRR NIH HHS
• M01 RR000080 NCRR NIH HHS
• RR00032 NCRR NIH HHS

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Affiliation(s)

Jennifer J Gassman Cleveland Clinic Department of Biostatistics, Ohio, 44195, USA.
Tom Greene
Jackson T Wright
Lawrence Agodoa
George Bakris
Gerald J Beck
Janice Douglas
Ken Jamerson
Julia Lewis
Michael Kutner
Otelio S Randall
Shin-Ru Wang

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Collaborators Collapse

Long-term antiproteinuric and renoprotective efficacy and safety of losartan in children with proteinuria

BACKGROUND

Angiotensin receptor antagonists are effective in reducing proteinuria by an action independent of blood pressure. As a consequence, such agents retard progressive renal dysfunction in adults with chronic proteinuria. Long-term efficacy and tolerability data in children are unavailable.

METHODS

Efficacy of losartan in reducing proteinuria and in preserving renal function was prospectively assessed in 52 consecutive children under 18 years of age with chronic proteinuric renal disorders, an initial creatinine clearance > or =25 mL/min/1.73 m(2), and a minimum of two or more follow-up visits. Thirty had proteinuria (P), and 22 had proteinuria combined with hypertension (P+H). Adverse effects were also evaluated.

RESULTS

Proteinuria had persisted or increased during a mean interval of 8.5 months before initiation of losartan at a mean dosage of 0.8 mg/kg/d. Mean protein excretion before starting losartan was 2453 mg/m(2)/d and fell by 34% at a mean follow-up time of six weeks (visit I, P<.05), and between 64% and 67% at mean follow-up periods of 0.38, 0.71, and 2.48 years corresponding to visits II, III, and IV (all P<.001 compared with baseline). The proportion of children with protein excretion exceeding 40 mg/m(2)/h (nephrotic range proteinuria) or nephrotic syndrome (>3500 mg/1.73 m(2)/d) fell from 42% and 40% at the start, to 24% and 8%, respectively, at visit IV (P<.01). Mean creatinine clearance as well as serum potassium and total CO(2) levels remained unchanged during the time of follow-up. Reduction in proteinuria in the P subgroup alone correlated with lowering in diastolic blood pressure at visit II and with both diastolic and systolic blood pressure at visits III and IV (all P<.05); it was largely independent of reduction in blood pressure in the P+H subgroup. The concomitant use of immunosuppressive agents in 28 of the 52 children had an influence on proteinuria only at baseline and at visit I (P<.05). There was no significant change in height or body mass index Z scores. Thirteen children had adverse effects potentially ascribed to losartan; most of these either improved or resolved with dosage adjustment or resulted in its discontinuation in 9 of the 52 children (17%).

CONCLUSION

Losartan therapy was associated with a marked and sustained reduction in proteinuria and in preservation of GFR in children with chronic proteinuric disorders. The association between proteinuria and systemic blood pressure reduction was complex: it was largely limited to the first year of losartan therapy and was more pronounced in the normotensive subgroup. Losartan was generally well tolerated.

The verapamil versus amlodipine in nondiabetic nephropathies treated with trandolapril (VVANNTT) study

BACKGROUND

We tested whether the combination of verapamil (V) or amlodipine (A) with trandolapril (T) affected proteinuria differently from T alone in patients with nondiabetic nephropathies.

METHODS

After T, 2 mg, in open conditions for 1 month, 69 patients were randomly assigned to be administered T, 2 mg, combined with V, 180 mg, plus a placebo or T, 2 mg, plus A, 5 mg, once a day in a double-blind fashion. Patients were followed up for 8 months.

RESULTS

Proteinuria diminished significantly after T treatment from mean protein excretion of 3,078 +/- 244 (SEM) to 2,537 +/- 204 mg/24 h (P = 0.018). In the randomized phase, there was a slight reduction in proteinuria in both groups without significant differences within and between treatments (T + V, protein from 2,335 +/- 233 to 2,124 +/- 247 mg/24 h; T + A, protein from 2,715 +/- 325 to 2,671 +/- 469 mg/24 h). The selectivity index (SI; calculated as the ratio of immunoglobulin G to albumin clearance) was slightly and not significantly reduced in patients treated with T plus V from a median of 0.20 (interquartile range, 0.13) to 0.16 (interquartile range, 0.15; P = not significant), whereas it significantly increased from 0.20 (interquartile range, 0.14) to 0.30 (interquartile range, 0.14; P = 0.0001) in patients treated with T plus A. Modifications in SI and serum creatinine levels at the end of the study from randomization were significantly directly correlated (r = 0.45; P = 0.001). The number of patients reporting adverse effects was significantly higher in the T plus A than T plus V group (63.8% versus 33.3%; P = 0.016).

CONCLUSION

In patients with nondiabetic proteinuric nephropathies treated with T, the combination of V or A does not significantly increase its antiproteinuric effect.

The renin-angiotensin-aldosterone system: cardiorenal effects and implications for renal and cardiovascular disease states

The renin-angiotensin-aldosterone system (RAAS) plays an integral role in maintaining vascular tone, optimal salt and water homeostasis, and cardiac function in humans. However, it has been recognized in recent years that pathologic consequences may also result from overactivity of the RAAS. Clinical disease states such as renal artery stenosis, hypertension, diabetic and nondiabetic nephropathies, left ventricular hypertrophy, coronary atherosclerosis, myocardial infarction, and congestive heart failure (CHF) are examples. Part of the adverse cardiorenal effects of the RAAS may be related to the prominent role that this system plays in the activation of the sympathetic nervous system, the dysregulation of endothelial function and progression of atherosclerosis, as well as inhibition of the fibrinolytic system. Also, direct profibrotic actions of angiotensin II and aldosterone in the kidney and heart promote end organ injury. Current basic science and clinical research supports the use of inhibitors of the RAAS, including angiotensin converting enzyme inhibitors, angiotensin receptor blockers, and aldosterone antagonists in treating hypertension, improving diabetic nephropathy and other forms of chronic kidney disease, preventing or ameliorating CHF, and optimizing prognosis after myocardial infarction.

Precocious activation of genes of the renin-angiotensin system and the fibrogenic cascade in IgA glomerulonephritis

BACKGROUND

The renin-angiotensin system (RAS) seems to play a pivotal role in progression of immunoglobulin A (IgA) nephropathy (IgAN). Accordingly, in patients with IgAN a relationship between the RAS and the fibrogenic cascade triggered by transforming growth factor-beta1 (TGF-beta1) should be observed. This study was carried out to obtain deeper insight into the regulation of RAS and the interaction with TGF-beta1 in the diseased kidney.

METHODS

Twenty renal biopsies from IgAN patients and five from renal cancer patients (controls) were analyzed in both microdissected glomerular and tubulointerstitial compartments by reverse transcription-polymerase chain reaction (RT-PCR). All patients had normal renal function. The expression of the following genes was determined: angiotensinogen (Agtg), renin, angiotensin-converting enzyme (ACE), angiotensin II (Ang II) type 1 and type II (AT1 and AT2 receptors), TGF-beta1, collagen IV (Coll IV), alpha-smooth muscle actin (alpha-SMA). Quantitative data were confirmed for TGF-beta1 and ACE genes by real-time PCR. Results. RAS genes were overexpressed in IgAN patients vs. control subjects. There was no difference between glomerular and tubulointerstitial RAS gene expression levels. On the contrary, the overactivation of fibrogenic cascade genes (TGF-beta1, Coll IV, alpha-SMA) in the tubulointerstitium was observed (TGF-beta1, glomerular 0.14 +/- 0.10 SD; tubulointerstial 0.34 +/- 0.20; P = 0.000) (alpha-SMA, glomerular 0.08 +/- 0.07; tubulointerstitial 0.35 +/- 0.19; P = 0.000) (Coll IV, glomerular 0.12 +/- 0.11; tubulointerstitial 0.22 +/- 0.10; P = 0.03). This fibrogenic cascade seems to be triggered by RAS as indicated by statistically significant correlations between the expression of their respective genes. A direct relationship between the putative Ang II activity and the expression of AT receptor genes was found in the tubulointerstitium, whereas in the glomeruli this relationship was negative. In the interstitium, statistically significant positive relationships emerged between interstitial infiltrates and the gene expression of Agtg, AT1 receptor, Coll IV, and TGF-beta1.

CONCLUSION

This study demonstrates that a tight regulation of the intrarenal RAS exists in IgAN and that it follows the general rules disclosed in animal models. Moreover, the RAS seems to be activated early in the diseased kidney and it appears that such activation drives inflammation and a parallel stimulation of the TGF-beta fibrogenic loop, particularly at the tubulointerstitial level.

The Chronic Renal Insufficiency Cohort (CRIC) Study: Design and Methods

Insights into end-stage renal disease have emerged from many investigations but less is known about the epidemiology of chronic renal insufficiency (CRI) and its relationship to cardiovascular disease (CVD). The Chronic Renal Insufficiency Cohort (CRIC) Study was established to examine risk factors for progression of CRI and CVD among CRI patients and develop models to identify high-risk subgroups, informing future treatment trials, and increasing application of preventive therapies. CRIC will enroll approximately 3000 individuals at seven sites and follow participants for up to 5 yr. CRIC will include a racially and ethnically diverse group of adults aged 21 to 74 yr with a broad spectrum of renal disease severity, half of whom have diagnosed diabetes mellitus. CRIC will exclude subjects with polycystic kidney disease and those on active immunosuppression for glomerulonephritis. Subjects will undergo extensive clinical evaluation at baseline and at annual clinic visits and via telephone at 6 mo intervals. Data on quality of life, dietary assessment, physical activity, health behaviors, depression, cognitive function, health care resource utilization, as well as blood and urine specimens will be collected annually. (125)I-iothalamate clearances and CVD evaluations including a 12-lead surface electrocardiogram, an echocardiogram, and coronary electron beam or spiral CT will be performed serially. Analyses planned in CRIC will provide important information on potential risk factors for progressive CRI and CVD. Insights from CRIC should lead to the formulation of hypotheses regarding therapy that will serve as the basis for targeted interventional trials focused on reducing the burden of CRI and CVD.

Autosomal dominant polycystic kidney disease - clinical and genetic aspects

Autosomal dominant polycystic kidney disease (ADPKD) is one of the most common inherited disorders in humans. It accounts for 8-10% of the cases of end-stage renal disease worldwide, thus representing a serious medical, economical and social problem. ADPKD is in fact a systemic disorder, characterized with the development of cysts in the ductal organs (mainly the kidneys and the liver), also with gastrointestinal and cardiovascular abnormalities. In the last decade there was significant progress in uncovering the genetic foundations and in understanding of the pathogenic mechanisms leading to the renal impairment. This review will retrace the current knowledge about the epidemiology, pathogenesis, genetics, genetic and clinical heterogeneity, diagnostics and treatment of ADPKD.

Retarding progression of chronic renal disease: the neglected issue of residual proteinuria

BACKGROUND

Findings that early changes in proteinuria independently predict long-term glomular filtration rate (GFR) decline (Delta GFR) would highlight proteinuria as a major determinant of progression in chronic renal disease.

METHODS

We investigated whether percent changes (3 months vs. baseline) in proteinuria (adjusted for concomitant changes in GFR) and residual proteinuria at 3 months, predicted Delta GFR [over a median (IQ range) follow up of 31.3 (24.5 to 50.3) months] in 273 patients with proteinuric chronic nephropathies enrolled in the Ramipril Efficacy In Nephropathy (REIN) study.

RESULTS

Short-term changes and residual proteinuria (r = -0.23, P = 0.0001 for both) significantly correlated with Delta GFR and, at multivariate analyses, independently predicted Delta GFR (beta = -0.23, P = 0.0002; beta = -0.21, P = 0.0004, respectively). For comparable levels of residual proteinuria, patients with greater short-term reduction had slower Delta GFR (-0.28 +/- 0.04 mL/min/1.73 m2/ vs. -0.53 +/- 0.07 mL/min/1.73 m2/month, P = 0.04). On ramipril and conventional treatment, specular short-term changes in proteinuria (-18.2 +/- 3.5% vs. 24.2 +/- 6.7%, P < 0.0001, respectively) were associated with significantly different Delta GFRs. However, similar changes in proteinuria resulted in a difference in Delta GFR (ramipril, 0.39 +/- 0.07 mL/min/1.73 m2/month; conventional therapy, 0.74 +/- 0.11 mL/min/1.73 m2/month; P < 0.01) that was sevenfold higher (0.35 vs. 0.05 mL/min/1.73 m2/month) in patients with basal proteinuria > or =3 g/24 hours as compared to those with basal proteinuria 1 to 3 g/24 hours (ramipril, 0.25 +/- 0.06 mL/min/1.73 m2/month; conventional therapy, 0.30 +/- 0.07 mL/min/1.73 m2/month; P = NS).

CONCLUSION

Regardless of blood pressure control and treatment randomization, short-term changes in proteinuria and residual proteinuria reliably predict long-term disease progression. Reducing proteinuria is renoprotective, particularly in nephrotic patients. As for arterial hypertension, proteinuria should be a specific target for renoprotective treatment.

Treating hypertension in diabetic nephropathy

OBJECTIVE

Control of hypertension in patients with diabetic nephropathy improves mortality and slows progression to end-stage renal disease. However, blood pressure is difficult to treat; multiple drug combination therapy is required and treatment algorithms to establish this are lacking. We used a stepped-care algorithm, centered on maximum doses of an ACE inhibitor or angiotensin II receptor blocker, to treat hypertension according to American Diabetes Association recommended blood pressure target goals (<130/80 mmHg) in patients with diabetic nephropathy.

RESEARCH DESIGN AND METHODS

We treated 49 consecutive patients with diabetes (13 with type 1 and 36 with type 2), diabetic nephropathy, and proteinuria > or =500 mg/24 h with a stepped-care blood pressure treatment algorithm. The level of blood pressure control achieved at most recent follow-up was assessed.

RESULTS

Patients were followed for a median of 18 months (range 9-48). Mean blood pressure achieved was 140/75 +/- 23/14 mmHg in patients with type 1 diabetes and 146/76 +/- 22/14 mmHg in patients with type 2 diabetes. Target blood pressure was reached in 16 (33%) patients, 6 of 13 patients with type 1 diabetes and 10 of 36 patients with type 2 diabetes, whereas systolic blood pressure remained above the target level in the remaining patients. There was no difference in baseline blood pressure, proteinuria, or serum creatinine level between patients who were treated to target and those who were not.

CONCLUSIONS

Levels of blood pressure control similar to those achieved in clinical trials in diabetic nephropathy were obtained with a stepped-care algorithm. However, in most patients, systolic blood pressure was difficult to control to target despite the use of multiple drug combination therapy.

Treatment of IgA nephropathy with ACE inhibitors: a randomized and controlled trial

Some retrospective studies have suggested a beneficial influence of angiotensin-converting enzyme (ACE) inhibitors on the progression of IgA nephropathy (IgAN), but prospective and controlled studies demonstrating this effect are lacking. Forty-four patients with biopsy-proven IgAN, proteinuria > or = 0.5 g/d, and serum creatinine (SCr) < or = 1.5 mg/dl were randomly assigned either to receive enalapril (n = 23) or to a control group (n = 21) in whom BP was controlled with antihypertensives other than ACE inhibitors. Primary outcome was renal survival estimated by a 50% increase in baseline SCr. Secondary outcomes were the presence of a SCr > 1.5 mg/dl at the last visit and the evolution of proteinuria. Baseline clinical findings were similar at baseline between enalapril-treated and control group, and there were no differences in BP control during follow-up. Mean follow-up was 78 +/- 37 mo in the enalapril group and 74 +/- 36 mo in the control group. Three patients (13%) in the enalapril group and 12 (57%) in the control group reached the primary end point (P < 0.05). Kaplan-Meier renal survival was significantly better in enalapril group than in control group: 100% versus 70% after 4 yr and 92% versus 55% after 7 yr (P < 0.05). Three patients in the enalapril group (13%) and 11 (52%) in the control group showed SCr > 1.5 mg/dl at the last visit (P < 0.05). Proteinuria significantly decreased in the enalapril group, whereas it tended to increase in the control group (P < 0.001 between groups). In conclusion, ACE inhibitors significantly improve renal survival in proteinuric IgAN with normal or moderately reduced renal function.

Very-low-dose combination: a first-line choice for the treatment of hypertension?

Essential hypertension is a very heterogeneous disease and different pressor mechanisms might interact to increase blood pressure. It is therefore not surprising that antihypertensive drugs given as monotherapies normalize blood pressure in only a proportion of hypertensive patients. This is, for instance, the case for diuretics, angiotensin-converting enzyme (ACE) inhibitors and angiotensin II type 1 (AT1) receptor antagonists administered as single agents. The rationale for combining antihypertensive agents relates in part to the concept that the blood pressure-decreasing effect may be enhanced when two classes are coadministered. Also, combination treatment serves to counteract the counter-regulatory mechanisms that are triggered whenever pharmacologic intervention is initiated and act to limit the efficacy of the antihypertensive medication. For example, the compensatory increase in renin secretion induced by sodium depletion may become the predominant factor sustaining high blood pressure. Simultaneous blockade of the renin-angiotensin system, with either an ACE inhibitor or an AT1 receptor blocker, makes this compensatory hyper-reninaemia ineffective and allows maximum benefit from sodium depletion. The increased effectiveness obtained by combining a blocker of the renin-angiotensin system with a low dose of a diuretic is not obtained at the expense of reduced tolerability compared with the individual components administered alone. Fixed very-low-dose combinations containing an ACE inhibitor or an AT1 receptor blocker and a diuretic are therefore likely to become increasingly used, not only as second-line therapy, but also as first-line treatment. This is the case, for instance, for the fixed very-low-dose combination of the ACE inhibitor perindopril (2 mg) and the diuretic indapamide (0.625 mg), as this preparation is very effective in decreasing blood pressure while maintaining a tolerability that is similar to that of placebo.

Constructing a database of individual clinical trials for longitudinal analysis

Individual patient data are often required to evaluate how patient-specific factors modify treatment effects. We describe our experience combining individual patient data from 1946 subjects in 11 randomized controlled trials evaluating the effect of angiotensin-enzyme converting (ACE) inhibitors for treating nondiabetic renal disease. We sought to confirm the results of our meta-analysis of group data on the efficacy of ACE inhibitors in slowing the progression of renal disease, as well as to determine whether any study or patient characteristics modified the beneficial effects of treatment. In particular, we wanted to find out if the mechanism of action of ACE inhibitors could be explained by adjusting for follow-up blood pressure and urine protein. Each trial site sent a database of multiple files and multiple records per patient containing longitudinal data of demographic, clinical, and medication variables to the data coordinating center. The databases were constructed in several different languages using different software packages with unique file formats and variable names. Over 4 years, we converted the data into a standardized database of more than 60,000 records. We overcame a variety of problems including inconsistent protocols for measurement of key variables; varying definitions of the baseline time; varying follow-up times and intervals; differing medication-reporting protocols; missing variables; incomplete, missing, and implausible data values; and concealment of key data in text fields. We discovered that it was easier and more informative to request computerized data files and merge them ourselves than to ask the investigators to abstract partial data from their files. Although combining longitudinal data from different trials based on different protocols in different languages is complex, costly, and time-intensive, analyses based on individual patient data are extremely informative. Funding agencies must be encouraged to provide support to collaborative groups combining databases.

Effect of pravastatin on loss of renal function in people with moderate chronic renal insufficiency and cardiovascular disease

Limited data suggest that HMG-CoA reductase inhibitors (statins) may slow loss of renal function in individuals with chronic renal insufficiency. This study was conducted to determine whether pravastatin reduced rates of loss of renal function in people with moderate chronic renal insufficiency. This was a post hoc subgroup analysis of a randomized double-blind placebo controlled trial. Data were analyzed from the CARE study (a randomized trial of pravastatin versus placebo in 4159 participants with previous myocardial infarction and total plasma cholesterol < 240 mg/dl). Participants with estimated GFR (MDRD-GFR) < 60 ml/min per 1.73 m(2) body surface area at baseline were considered to have moderate chronic renal insufficiency. Multivariate regression was used to calculate rates of decline in MDRD-GFR for individuals receiving pravastatin and placebo, controlling for prospectively determined covariates that might influence rates of renal function loss. Change in renal function could be calculated in 3384 individuals, of whom 690 (20.4%) had MDRD-GFR < 60 ml/min per 1.73 m(2) and were eligible for inclusion. Among all individuals with MDRD-GFR < 60 ml/min per 1.73 m(2)), the MDRD-GFR decline in the pravastatin group was not significantly different from that in the placebo group (0.1 ml/min per 1.73 m(2)/yr slower; 95% CI, -0.2 to 0.4; P = 0.49). However, there was a significant stepwise inverse relation between MDRD-GFR before treatment and slowing of renal function loss with pravastatin use, with more benefit in those with lower MDRD-GFR at baseline (P = 0.04). Rate of change in MDRD-GFR in the pravastatin group was 0.6 ml/min per 1.73 m(2)/yr slower than placebo (95% CI, -0.1 to 1.2; P = 0.07) in those with MDRD-GFR < 50 ml/min, and 2.5 ml/min per 1.73 m(2)/yr slower (95% CI, 1.4 to 3.6 slower; P = 0.0001) in those with MDRD-GFR < 40 ml/min per 1.73 m(2)/yr. Pravastatin also reduced rates of renal loss to a greater extent in participants with than without proteinuria at baseline (P = 0.006). It is concluded that pravastatin may slow renal function loss in individuals with moderate to severe kidney disease, especially those with proteinuria. These findings require confirmation by a large randomized trial conducted specifically in people with chronic renal insufficiency.

Results of a pilot pharmacotherapy quality improvement program using fixed-dose, combination amlodipine/benazepril antihypertensive therapy in a long-term care setting

BACKGROUND

Hypertension is common in older adults (aged > or =65 years). Treatment frequently requires multiple medications and can be expensive.

OBJECTIVE

This study measured the impact of substituting low-dose, fixed-combination therapy using the calcium channel blocker (CCB) amlodipine and the angiotensin-converting enzyme (ACE) inhibitor benazepril for high-dose CCB monotherapy or dual therapy with a CCB and an ACE inhibitor on antihypertensive drug costs, the incidence of adverse events, and blood-pressure control.

METHODS

A multicenter, pilot pharmacotherapy quality improvement program was undertaken in a long-term care facility setting. Consultant pharmacists reviewed pharmacy records and medical charts from long-term care facilities, identifying older patients with a diagnosis of hypertension who either took CCB concomitantly with an ACE inhibitor or experienced adverse events on high-dose CCB therapy. Eligible patients were identified and their physicians contacted regarding switching them to fixed-dose combination therapy.

RESULTS

A total of 51 patients at 17 facilities were switched to fixed-dose amlodipine/benazepril combination therapy; 94.1% were women and 5.9% were men (mean age, 85.1 years; range, 64-99 years). The mean number of comorbidities was 1.6. During the subsequent 2 months, mean blood pressure remained at levels similar to those at baseline. The number of patients reporting at least 1 drug-related adverse event decreased by 81.8% (P < 0.05), and the incidence of edema decreased by 75.0%. The mean per-patient cost of antihypertensive drugs decreased by 33.1% (P < 0.001), a mean per-patient savings of 19.21 US dollars per month.

CONCLUSION

In patients aged > or =65 years with hypertension in long-term care facilities, a change from high-dose CCB monotherapy or CCB/ACE-inhibitor dual therapy to fixed-dose combination amlodipine/benazepril therapy significantly reduced drug costs and the incidence of adverse events and maintained blood-pressure control.

High urine volume and low urine osmolality are risk factors for faster progression of renal disease

BACKGROUND

Increased fluid intake slows renal disease progression in animal models. The relevance of these findings to human renal disease is not clear, although increased fluid intake often is recommended to patients with chronic renal insufficiency. This study tested the hypothesis that urine volume, urine osmolality (Uosm), or both are significantly associated with glomerular filtration rate (GFR) decline in patients with chronic renal insufficiency.

METHODS

This is a retrospective analysis of Modification of Diet in Renal Disease (MDRD) study A patients with (N = 139) and without polycystic kidney disease (PKD; N = 442). The key outcome measure was GFR slope in relation to mean 24-hour urine volume and Uosm during follow-up in study A (mean, 2.3 years).

RESULTS

The regression of GFR slope on mean follow-up 24-hour urine volume (adjusted for body surface area and MDRD diet and blood pressure group) showed that the greater the urine volume, the faster the GFR decline in patients both with and without PKD. For example, the difference in GFR slope for those with a mean follow-up 24-hour urine volume of 2.4 versus 1.4 L was -1.01 mL/min/y (confidence interval, -0.27 to -1.75) for patients without PKD and -1.20 mL/min/y (confidence interval, -0.06 to -2.34) for those with PKD. A similar but inverse relationship was shown between GFR decline and mean 24-hour Uosm in patients with (P = 0.01) and without PKD (P = 0.001). These associations remained significant after adjustment for 13 relevant baseline and follow-up covariates.

CONCLUSION

Sustained high urine volume and low Uosm are independent risk factors for faster GFR decline in patients with chronic renal insufficiency. Thus, high fluid intake does not appear to slow renal disease progression in humans. We suggest that until better evidence becomes available, patients with chronic renal insufficiency should generally let their thirst guide fluid intake. The advice to avoid "pushing fluids" might be particularly important for patients with PKD.

Outcomes in kidney transplantation

It is estimated that there are greater than 100000 kidney transplant recipients with a functioning graft in the United States. Recent advances in immunosuppression have improved short-term graft survival rates and decreased early mortality by decreasing the incidence and therapy for acute rejection episodes. For those accepted on the waiting list, transplant prolongs patient survival compared with remaining on dialysis. During the 1990s, 3 new immunosuppressive drugs were introduced in clinical kidney transplantation. All were approved for use by the Food and Drug Administration after large, controlled, randomized trials. Mycophenolate mofetil (MMF), when combined with cyclosporine (CSA) and prednisone, lowered acute rejection rates by nearly 50% compared with control. Tacrolimus compared with CSA also significantly reduced acute rejection rates in kidney transplant recipients, but was associated with a significant increase in posttransplant diabetes mellitus (PTDM) in the early trials. When evaluated in combination with MMF, the incidence of PTDM was much lower. At the end of the decade, sirolimus was shown in several randomized trials to lower acute rejection rates and is believed to be less nephrotoxic compared with calcineurin inhibitors. All of the randomized trials were not statistically powered to assess long-term superiority. Registry analyses have been performed that appear to show some long-term benefit of immunosuppressive therapy with MMF. Other outcome assessments in kidney transplant recipients include risk factors for chronic allograft nephropathy, hypertension, hyperlipidemia, and bone disease. Although there are few randomized trials, understanding of the significance of these common complications has progressed and strategies for therapy and intervention have been developed. This article focuses on the randomized trials of immunosuppressive therapy and complications associated with use of these drugs. In addition, we review the current management and intervention for the comorbidities associated with the long-term clinical management of the kidney transplant recipient.

Effect of telmisartan on the proteinuria and circadian blood pressure profile in chronic renal patients

Telmisartan is a type 1 angiotensin II (AT(1)) receptor blocker, effective and safe in the treatment of arterial hypertension. However, data with respect to circadian blood pressure (BP) monitoring and urinary protein (uP) excretion are lacking in normotensive or mild hypertensive patients with chronic renal diseases. This study has evaluated the effects of 80 mg telmisartan, given as monotherapy, on 24 h BP levels and uP loss in 16 non-diabetic patients affected by proteinuric renal disease. These patients did not meet the recommended values of mean BP, i.e. < 98 mmHg, when proteinuria was 0.5-1.0 g/d and mean BP < 92 mmHg, when proteinuria was 1-3 g/d. Patients with diastolic BP > 114 mmHg, nephrotic syndrome or severe renal failure (creatinine clearance < 20 ml/min) were excluded. After 4.2 +/- 2.7 month therapy, ambulatory BP monitoring showed a significant decrease (P < 0.001) of 24 h BP levels: systolic 135 +/- 11 vs. 122 +/- 13 mmHg, diastolic 84.4 +/- 8.1 vs. 75.9 +/- 8.5 mmHg, mean 101 +/- 8 vs. 91 +/- 9 mmHg. The effect was quite evident during either day-time or night-time. Clinic BP levels also significantly decreased (P < 0.001), and five patients reached the target values. uP excretion lowered by 37% (median) from 1.60 +/- 0.90 to 1.06 +/- 0.63 g/24 h (P < 0.01). No change in creatinine clearance (53.3 +/- 31.1 vs. 51.7 +/- 30.9 ml/min) or serum potassium level (4.3 +/- 0.3 vs. 4.4 +/- 0.4 mEq/l) was observed. Our results show that 80 mg of telmisartan, taken once daily, is effective in reducing uP excretion and BP throughout the 24 h, in normotensive or mild hypertensive renal patients. Since evidence exists that adequate control of BP, including during night-time, and reduction of proteinuria play a crucial role in the protection of renal function, telmisartan can be usefully considered in the conservative treatment of renal patients.

Cardiovascular risk in patients with mild renal insufficiency

We reviewed the evidence linking mild renal insufficiency (MRI) to an increased cardiovascular risk. A number of cardiovascular risk factors become prevalent with MRI, including night-time hypertension, increase in lipoprotein(a), in homocysteine, in asymmetric dimethyl-arginine (ADMA), markers and mediators of inflammation, and insulin resistance. Also, an epidemiologic association between coronary artery disease and nephrosclerosis, a frequent cause of mild renal insufficiency in the elderly, is documented. In the middle-aged, general population MRI, found in 8% of women and 9% of men, was not associated with cardiovascular disease. However, in a representative sample of middle-aged British men, the risk of stroke was 60% higher for the subgroup of people with MRI; in people at high cardiovascular risk (mostly coronary disease), the HOPE study found a 2-fold (unadjusted), or 1.4-fold (adjusted), higher incidence of cardiovascular outcomes with MRI. The incidence of primary outcome increased with the level of serum creatinine. Several studies determined the cardiovascular risk associated with MRI in hypertension. In HDFP, as in HOPE, cardiovascular mortality increased with higher serum creatinine (five-fold difference in cardiovascular mortality between the lowest and the highest creatinine strata). The risk associated with renal insufficiency was independent from other classic cardiovascular risk factors. In hypertensives with low risk, the HOT, and a small Italian trial found about a doubling in cardiovascular outcomes in MRI. However, in MRFIT, increase in follow-up creatinine predicted future cardiovascular disease, not baseline creatinine. These observational data suggest that MRI, independent of etiology, is a strong predictor of cardiovascular disease, present in 10% of a population at low risk, and up to 30% at high cardiovascular risk. No prospective therapeutic trials, aimed at reducing the cardiovascular burden in people with MRI, are available. Subgroup analyses of the HOPE study indicate that ACE inhibition with ramipril is beneficial without an increased risk for side effects like acute renal failure or hyperkalemia. Thus, the frequent practice of withholding ACE inhibitors from patients with mild renal insufficiency is unwarranted, especially since this identifies a group at high risk that appears to benefit most from treatment. In addition, there is evidence that ACE inhibitors improve renal outcomes in renal insufficiency. Prospective studies should test the predictive power of MRI for cardiovascular disease and therapeutic options.

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

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

Analysis of metabolic parameters as predictors of risk in the RENAAL study

OBJECTIVE

Metabolic factors such as glycemic control, hyperlipidemia, and hyperkalemia are important considerations in the treatment of patients with type 2 diabetes and nephropathy. In the RENAAL (Reduction of End Points in Type 2 Diabetes With the Angiotensin II Antagonist Losartan) study, losartan reduced renal outcomes in the patient population. This post hoc analysis of the RENAAL study reports the effects of losartan on selected metabolic parameters and assesses the relationship between baseline values of metabolic parameters and the primary composite end point or end-stage renal disease (ESRD).

RESEARCH DESIGN AND METHODS

Glycemic control (HbA(1c)) and serum lipid, uric acid, and potassium levels were compared between the losartan and placebo groups over time, and baseline levels were correlated with the risk of reaching the primary composite end point (doubling of serum creatinine, ESRD, or death) or ESRD alone.

RESULTS

Losartan did not adversely affect glycemic control or serum lipid levels. Losartan-treated patients had lower total (227.4 vs. 195.4 mg/dl) and LDL (142.2 vs. 111.7 mg/dl) cholesterol. Losartan was associated with a mean increase of up to 0.3 mEq/l in serum potassium levels; however, the rate of hyperkalemia-related discontinuation was similar between the placebo and losartan groups. Univariate analysis revealed that baseline total and LDL cholesterol and triglyceride levels were associated with increased risk of developing the primary composite end point. Similarly, total and LDL cholesterol were also associated with increased risk of developing ESRD.

CONCLUSIONS

Overall, losartan was well tolerated by patients with type 2 diabetes and nephropathy and was associated with a favorable effect on the metabolic profile of this population.

Treatment of lupus nephritis

Renal involvement in systemic lupus erythematosus (SLE) is a serious complication of the disease. However, the prognosis of patients with lupus nephritis is continually improving with 10-year survival rates now greater than 75%. This improvement reflects earlier diagnosis due to more sensitive and specific diagnostic tests, better clinical appreciation of the natural history, and improved treatment of SLE and its manifestations. This review of the treatment of lupus nephritis has graded the level of evidence of specific treatment using the guidelines of the US Preventive Service Task Force. Although many new treatments have been advocated, the best evidence for treating proliferative lupus nephritis relies on a strategy combining specific treatment of the SLE as well as generalised treatment of the associated comorbidities. This strategy involves a combination of corticosteroids and cytotoxic agents plus or minus the adjunctive use of antimalarials, coordinated aggressive management of hypertension, proteinuria, infections, dyslipidaemia, thrombotic coagulopathy and potential renal replacement therapies.

Expression and cellular localisation of renal endothelin-1 and endothelin receptor subtypes in autosomal-dominant polycystic kidney disease

The major factors influencing the rate of progression of chronic renal disease in autosomal-dominant polycystic kidney disease (ADPKD) are unknown and there are currently no effective treatments for slowing the progression of chronic renal failure in ADPKD patients. As a first step in investigating the potential role of endothelin-1 (ET1) and its receptors (ETA and ETB) in the pathophysiology of progression in ADPKD, we have studied their expression and cellular localisation in ADPKD kidney. Immunoreactive ET1 was detected in cyst epithelia, mesangial cells and vascular smooth muscle cells suggesting continuing ET1 synthesis in the cystic kidney. Compared to healthy controls, ETA mRNA was 5-10-fold higher in ADPKD cystic kidney. In cystic kidney, neo-expression of ETA receptors was found overlying glomeruli and cysts and markedly increased in medium-sized renal arteries by microautoradiography. This is the first study to demonstrate a specific upregulation of ETA receptors in human renal disease. Future studies should address whether ETA selective antagonists may be effective in slowing renal disease progression in ADPKD.

Distinct time courses of renal protective action of angiotensin receptor antagonists and ACE inhibitors in chronic renal disease

Although the angiotensin receptor antagonist (ARB) shares the angiotensin-II-blocking activity with the angiotensin-converting enzyme inhibitor (ACE-I), pharmacological mechanisms of action of these agents differ. We evaluated the temporal profiles of action of ACE-I and ARB on urinary protein excretion and nitrate/nitrate (NO(x)) excretion in hypertensive (140 and/or 90 mmHg) patients with chronic renal disease (serum creatinine < 265 (range, 44-265) micromol/l or creatinine clearance > 30 (range, 30-121) ml/min). Patients with mild (<1 g/day; range, 0.4-1.0) and moderate proteinuria (>1 g/day; range, 1.1-6.9) were randomly assigned to ACE-I- and ARB-treated groups, and were treated with ACE-I (trandolapril or perindopril) or ARB(losartan or candesartan) for 48 weeks. In all groups, treatment with ACE-I or ARB decreased blood pressure to the same level, but had no effect on creatinine clearance. In patients with mild proteinuria, neither ACE-I nor ARB altered urinary protein excretion. In patients with moderate proteinuria, ACE-I caused 44 +/- 6% reduction in proteinuria (from 2.7 +/- 0.5 to 1.5 +/- 0.4 g/day, n = 14) at 12 weeks, and this beneficial effect persisted throughout the protocol (48 weeks, 1.2 +/- 0.2 g/day). In contrast, ARB did not produce a significant decrease in proteinuria at 12 weeks (23 +/- 8%, n = 13), but a 41 +/- 6% reduction in proteinuria was observed at 48 weeks. Similarly, although early (12 weeks) increases in urinary NO(x) excretion were observed with ACE-I (from 257 +/- 70 to 1111 +/- 160 micromol/day) and ARB (from 280 +/- 82 to 723 +/- 86 micromol/day), the ARB-induced increase in NO(x) excretion was smaller than that by ACE-I (P < 0.05). In conclusion, although both ACE-I and ARB reduce blood pressure similarly, the effect of these agents on proteinuria differs in chronic renal disease with moderate proteinuria. Relatively early onset of the proteinuria-reducing effect was observed with ACE-I, which paralleled the increase in urinary NO(x) excretion. Conversely, ARB decreased proteinuria and increased urinary NO(x) excretion gradually. These time course-dependent changes in proteinuria and urinary NO(x) may reflect the pharmacological property of ACE-I and ARB, with regard to the action on bradykinin.

Predictive factors of progression of chronic renal insufficiency: a multivariate analysis

The purpose of this study was to identify clinical, nutritional, and laboratory factors associated with the rate of progression of chronic renal insufficiency among children and adolescents admitted to a pre-end-stage renal failure (ESRF) interdisciplinary program. Sixty-two children and adolescents aged 2 months to 19 years with chronic renal failure on conservative management were prospectively followed from 1990 to 1999. The following variables were analyzed: age at admission, sex, race, blood pressure, primary renal disease, Z scores for weight and height, glomerular filtration rate (GFR), urea, and presence and degree of proteinuria. Progression to ESRF was assigned as a dependent variable. The analysis was conducted in two steps. In a univariate analysis, variables associated with ESRF outcome were identified by the log-rank test. Then, the variables that were significantly associated with adverse outcome were included in a multivariate analysis. This analysis, using the Cox proportional hazards model, was performed to identify variables that were independently associated with a worse prognosis. Only variables that remained independently associated with adverse outcome were included in the final model. Twenty-one (34%) patients evolved to ESRF during a median follow-up of 43 months. Two variables were identified as independent predictors of progression to ESRF: GFR under 30 ml/min (RR=3, 95% CI=1.7-5.3, P=0.0001) and severe proteinuria (RR=3.1, 95% CI=1.2-7.6, P=0.01). The combination of two factors-GFR lower than 30 ml/min and presence of severe proteinuria on admission-was an independent indicator of adverse outcome in children and adolescents with chronic renal insufficiency who were conservatively managed.

Antiproteinuric effect of niceritrol, a nicotinic acid derivative, in chronic renal disease with hyperlipidemia: a randomized trial

PURPOSE

Lipoprotein (a) [Lp(a)] levels increase in patients with renal disease. We administered niceritrol, a nicotinic acid derivative, to patients with chronic renal disease and a high serum Lp(a) level, and studied its effects on lipid metabolism, proteinuria, and renal function.

METHODS

Thirty-three patients with chronic renal disease whose serum Lp(a) levels were > or = 15 mg/dL were randomly (but not blindly) assigned to treatment with niceritrol (n = 16) or to an untreated control group (n = 17). Parameters of lipid metabolism, excretion of urinary protein, and renal function were examined for 12 months.

RESULTS

Changes in urinary protein excretion, as well as Lp(a) levels, differed significantly between the two groups. The mean (+/- SD) change from baseline in excretion of urinary protein was 0.77 +/- 1.23 g/d in the control group compared with -1.41 +/- 2.26 g/d in the niceritrol group at 12 months (P =0.003). Mean Lp(a) levels increased by 3 +/- 10 mg/dL in the control group compared with a decrease of 10 +/- 13 mg/dL in the niceritrol group at 12 months (P =0.004). The mean creatinine clearance declined by 10 +/- 12 mL/min in the control group, compared with 1 +/- 13 mL/min in the niceritrol group at 12 months (P =0.06).

CONCLUSION

Lipid levels improved with niceritrol treatment, whereas the excretion of urinary protein decreased, perhaps slowing the rate of loss of renal function in chronic renal disease.

Proteinuria and the risk of developing end-stage renal disease

BACKGROUND

Dipstick urinalysis for proteinuria and hematuria has been used to screen renal disease, but evidence of the clinical impact of this test on development of end-stage renal disease (ESRD) is lacking.

METHODS

We assessed development of ESRD through 2000 in 106,177 screened patients (50,584 men and 55,593 women), 20 to 98 years old, in Okinawa, Japan, who participated in community-based mass screening between April 1983 and March 1984. We used data from the Okinawa Dialysis Study Registry to identify ESRD patients. Multivariate logistic analyses were performed to calculate adjusted odds ratio and 95% confidence interval (95% CI) for the significance of proteinuria and hematuria on the risk of developing ESRD with confounding variables such as age, gender, blood pressure, and body mass index. A similar analysis was repeated in a subgroup of screened patients in whom serum creatinine data existed.

RESULTS

During 17 years of follow-up, 420 screened persons (246 men and 174 women) entered the ESRD program. We identified a strong, graded relationship between ESRD and dipstick urinalysis positive for proteinuria; adjusted odds ratio (95% CI) was 2.71 (2.51 to 2.92, P < 0.001). Similar trends were observed after adding serum creatinine data. Compared with dipstick-negative proteinuria, adjusted odds ratio (95% CI) of proteinuria (1+) was 1.93 (1.53 to 2.41, P < 0.001) in men and 2.42 (1.91 to 3.06, P < 0.001) in women.

CONCLUSION

Proteinuria was a strong, independent predictor of ESRD in a mass screening setting. Even a slight increase in proteinuria was an independent risk factor for ESRD. Therefore, asymptomatic proteinuria warrants further work-up and intervention.

Angiotensin II and the glomerulus: focus on diabetic kidney disease

The renin-angiotensin system plays a key role in the progression of kidney disease, in addition to its well-described role in the maintenance of extracellular fluid volume and blood pressure. Recent studies have shown that blockade of the renin-angiotensin system at the level of the angiotensin II type 1 receptor can have important effects on proteinuria and the rate of progression of kidney disease in patients with type 2 diabetes mellitus. This review first discusses recent experimental studies relating angiotensin II to kidney function in diabetes mellitus and changes in glomerular permselectivity, and then focuses on recent clinical trials with angiotensin II receptor blockers in patients with type 2 diabetes mellitus.

Induction of MIF synthesis and secretion by tubular epithelial cells: a novel action of angiotensin II

BACKGROUND

Angiotensin II (Ang II) plays an important role in the development of renal injury through its vasoactive and proinflammatory activities. We investigated whether some of the effects of Ang II could be mediated through the production of macrophage migration inhibitory factor (MIF).

METHODS

Groups of rats underwent sham surgery (sham), subtotal nephrectomy (STNx), or STNx plus treatment with irbesartan. Renal tissue was examined 12 weeks postsurgery for MIF mRNA expression and leukocyte accumulation. To determine whether Ang II had a direct effect on MIF production, mRNA synthesis and protein secretion were examined in proximal tubular epithelial (NRK52E and MCT) cell lines.

RESULTS

MIF mRNA was strongly expressed in 5.4%+/- 1.1% (mean +/- SD) of cortical tubules of sham-operated rats. This was significantly up-regulated in STNx rats (44.9%+/- 22.6%) and was abrogated by administration of irbesartan (2.8%+/- 2.4%). STNx resulted in significant glomerular and interstitial accumulation of macrophages and T cells, which correlated with glomerular and tubular MIF mRNA expression, respectively. In vitro studies of tubular epithelial cells revealed that Ang II caused a twofold increase in MIF mRNA expression in NRK52E and MCT cells, which was abrogated by irbesartan. In addition, Ang II induced a rapid release of 50% of MIF protein from NRK52E cells within 20 minutes.

CONCLUSION

This study has demonstrated that Ang II up-regulates MIF mRNA production and MIF protein secretion by tubular epithelial cells. Ang II may promote accumulation and activation of interstitial leukocytes via induction of MIF synthesis and secretion in renal tubular epithelial cells. This may be an important mechanism by which Ang II mediates renal injury.

Aldosterone in renal disease

PURPOSE OF REVIEW

Interruption of the renin-angiotensin-aldosterone system, chiefly with angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers, has yielded beneficial results in retarding injury and progression in numerous intrinsic renal diseases. The renoprotection offered by these agents is incomplete and far from optimal. Studying mediators of progression other than angiotensin II is therefore extremely important. The emerging role of aldosterone in progression of renal disease and the utility of its antagonism is discussed here.

RECENT FINDINGS

The experimental evidence linking aldosterone to renal disease is discussed. The exciting results from clinical studies employing mineralocorticoid receptor blockers are also described.

SUMMARY

Aldosterone antagonism offers additional antiproteinuric benefits to those achieved with angiotensin-converting enzyme inhibition. Long-term trials addressing effectiveness and safety, especially in regards to hyperkalemia, are greatly needed.

Combination is better than monotherapy with ACE inhibitor or angiotensin receptor antagonist at recommended doses

OBJECTIVE

The combination of an angiotensin-converting enzyme (ACE) inhibitor and an angiotensin II (Ang II) receptor antagonist (ARB) could provide a higher degree of blockade of the renin-angiotensin system(RAS) than either agent alone. The primary aim of this study was to look at the effect of three therapeutic regimens (titrated ACE inhibitor (ACE-I) versus titrated ARB versus the combination of an ACE-I and an ARB) on the attainment of adequate blood pressure (BP) control and antiproteinuric effect. Both ACE-I and ARB were titrated as monotherapy up to the maximal recommended dose.

METHODS

A pilot randomised, parallel group open-label study was conducted in 36 patients with primary renal disease, proteinuria above 1.5 g/day and BP >140/90 mmHg while on therapy with an ACE-I. Patients were randomly assigned to (1) benazepril, n=12; (2) valsartan, n=12; or (3) benazepril plus valsartan, n=12. Other antihypertensive therapies could also be added to attain goal BP (<140/90 mmHg). The primary endpoint was the change in proteinuria during six months of follow-up.

RESULTS

In the presence of similar BP decreases and stable creatinine clearance values, mean proteinuria decreases were 0.5+1.7, 1.2+2.0 and 2.5+1.8 g/day in groups 1, 2 and 3, respectively. When compared with baseline values, only the fall induced by the combination of ARB and ACE-I attained statistical significance (p<0.05).

CONCLUSION

The antiproteinuric capacity of monotherapy at recommended doses with either an ACE-I or an ARB is lower than that obtained with the combination of the two drugs.

Development of renal disease in people at high cardiovascular risk: results of the HOPE randomized study

In people with diabetes, renal disease tends to progress from microalbuminuria to clinical proteinuria to renal insufficiency. Little evidence has been published for the nondiabetic population. This study retrospectively analyzed changes of proteinuria over 4.5 yr in the HOPE (Heart Outcomes and Prevention Evaluation) study, which compared ramipril's effects to placebo in 9297 participants, including 3577 with diabetes and 1956 with microalbuminuria. This report is restricted to 7674 participants with albuminuria data at baseline and at follow-up. Inclusion criteria were known vascular disease or diabetes plus one other cardiovascular risk factor, exclusion criteria included heart failure or known impaired left ventricular function, dipstick-positive proteinuria (>1+), and serum creatinine >2.3 mg/dl (200 microM). Baseline microalbuminuria predicted subsequent clinical proteinuria for the study participants overall (adjusted odds ratio [OR], 17.5; 95% confidence interval [CI], 12.6 to 24.4), in participants without diabetes (OR, 16.7; 95% CI, 8.6 to 32.4), and in participants with diabetes (OR, 18.2; 95% CI, 12.4 to 26.7). Any progression of albuminuria (defined as new microalbuminuria or new clinical proteinuria) occurred in 1859 participants; 1542 developed new microalbuminuria, and 317 participants developed clinical proteinuria. Ramipril reduced the risk for any progression (OR, 0.87; 95% CI, 0.78 to 0.97; P = 0.0146). People without and with diabetes who are at high risk for cardiovascular disease are also at risk for a progressive rise in albuminuria. Microalbuminuria itself predicts clinical proteinuria in nondiabetic and in diabetic people. Ramipril prevents or delays the progression of albuminuria.

The African American Study of Kidney Disease and Hypertension (AASK) trial: what more have we learned?

The final results of the African American Study of Kidney Disease and Hypertension (AASK) have shown that the angiotensin-converting enzyme inhibitor ramipril was better than the beta blocker metoprolol or the dihydropyridine calcium channel blocker amlodipine in slowing the rate of glomerular filtration rate decline in African American patients with mild to moderate renal insufficiency. Of note, there was no difference between the 92 mm Hg or less (lower group) and the 102-107 mm Hg (usual) mean arterial pressure groups as regards the secondary clinical composite end point. The secondary clinical composite end point in this study comprised a threshold drop of at least 50% or 25 mL/min in glomerular filtration rate, death, or reaching end-stage renal disease. The final results from this study would suggest that reduction in blood pressure to levels below those currently advocated for cardiovascular risk reduction, although a clearly attainable goal in this population, does not provide readily identifiable benefits to African Americans with hypertensive nephrosclerosis. Importantly, this study provides the basis for the primary use of angiotensin-converting enzyme inhibitors in an African American population with the characteristics of those studied in AASK. It remains to be determined if this represents a class effect for all angiotensin-converting enzyme inhibitors.

Angiotensin antagonists and steroids in the treatment of focal segmental glomerulosclerosis

The use of angiotensin converting enzyme inhibitors (ACEIs) along with good blood pressure control have been shown to significantly decrease the level of proteinuria and slow the progression of renal insufficiency in patients with nondiabetic glomerular disease including focal segmental glomerulosclerosis (FSGS). Thus, this should be part of the therapeutic approach for all proteinuric patients with FSGS and should be considered the mainstay of therapy for patients with FSGS secondary to conditions associated with hyperfiltration and/or reduced nephron mass and those patients with nonnephrotic primary FSGS. However, nephrotic patients with primary FSGS may continue to have marked proteinuria and progression of renal disease despite these measures and thus require a more aggressive approach with the use of steroids and immunosuppressive agents. Although primary FSGS was once thought to be a steroid-nonresponsive lesion, recent experience has provided a note of optimism in the use of steroids and immunosuppressive agents in treating this otherwise progressive glomerulopathy. As a result, a course of steroid therapy in primary FSGS is now warranted in nephrotic patients with reasonably well preserved renal function in whom it is not otherwise contraindicated.

Clinical epidemiology of cardiac disease in dialysis patients: left ventricular hypertrophy, ischemic heart disease, and cardiac failure

Patients with end-stage renal disease (ESRD) are at extreme cardiovascular risk. At least half of all patients starting dialysis therapy have overt cardiovascular disease (CVD). In addition, recent studies suggest annual incidence rates for new-onset cardiac failure, peripheral vascular disease, ischemic heart disease (IHD), and stroke of approximately 7%, 7%, 5%, and 1%, respectively. High-level exposure to traditional risk factors, such as smoking and dyslipidemia, hemodynamic overload factors, such as anemia and hypertension, and a myriad of metabolic factors related to uremia are all likely to play a role. There has been explosive growth in observational studies and a heartening, if less dramatic, increase in risk factor intervention trials, suggesting that risk factor modification can lead to meaningful benefit.

Treatment of hypertension in renal transplant recipients

PURPOSE OF REVIEW

Hypertension is very common in renal transplant recipients and is a significant risk factor for mortality from cardiovascular diseases and for development of graft dysfunction.

RECENT FINDINGS

Recent guidelines for the treatment of hypertension (Joint National Committee on Prevention, Detection, and Treatment of High Blood Pressure VI Report and World Health Organization Guidelines) do not directly address post-transplant hypertension. Specific recommendations for the drug treatment of hypertension in renal allograft recipients have not been given in the Clinical Practice Guidelines of the American Society of Transplantation or those of the European Renal Association.

SUMMARY

The present paper summarizes some important aspects of post-transplant hypertension and discusses potential treatment strategies aimed at reducing blood pressure and thus improving patient and allograft survival.

Drugs that interrupt the renin-angiotensin system should be among the preferred initial drugs to treat hypertension

The goal of antihypertensive therapy is to provide effective treatment that can be sustained lifelong, while lowering elevated blood pressure and preventing hypertensive end-organ damage and mortality. Angiotensin-converting enzyme (ACE) inhibitors and angiotensin II antagonists (AIIAs) control blood pressure as well as other available classes of antihypertensive drugs. The ACE inhibitors have been demonstrated to reduce the incidence of stroke, reverse left ventricular hypertrophy, and improve congestive heart failure symptomatology and mortality to a similar degree as diuretics and beta-adrenergic blockers. ACE inhibitors reduce postmyocardial infarction recurrence, improve congestive heart failure symptomatology and mortality, and slow the progression of glomerular renal disease. The AIIAs reverse left ventricular hypertrophy. Several of these agents have been shown to improve congestive heart failure symptomology and mortality, to reduce the occurrence of early atherosclerotic vascular disease, and to slow the progression of renal failure in type 2 diabetes mellitus nephropathy. One AIIA has reduced the incidence of end-stage renal disease in non-insulin-dependence diabetes mellitus nephropathy over 3 years. Ideally, antihypertensive therapy should maintain or improve the patients quality of life without creating side effects or adverse laboratory effects. Among the available nine classes of antihypertensive drugs, ACE inhibitors and the AIIAs come close to meeting the description of an ideal drug. AIIAs and ACE inhibitors, two classes of antihypertensive drugs that reduce the activity of the renin-angiotensin II system, should be among the preferred first-step drugs for the treatment of hypertension.

Role of proteinuria in the regulation of renal renin-angiotensin system components in unilateral proteinuric rats

Renin-angiotensin system (RAS) overactivity has been implied in progressive renal function loss. We investigated whether changes in the renal expression of RAS components are specifically associated with the proteinuric kidney. Unilateral adriamycin-induced proteinuria was obtained by clamping the left renal artery before injection of adriamycin. In control animals, both left and right renal arteries were clamped. Twelve weeks later, mRNA expression of RAS components was determined in both kidneys. In the affected and non-affected kidney of the unilateral proteinuric rat, we demonstrate up-regulation of angiotensin- converting enzyme (ACE) mRNA (213%+22 and 188%+24 of controls, respectively), up-regulation of transforming growth factor beta (TGF-beta) mRNA (956%+229 and 418%+56) and down-regulation of angiotensin type 2 receptor (AT2-R) mRNA (24%+5 and 20%+5). The expression of angiotensin type 1 receptor (AT1-R) mRNA and inositol 1,4,5- trisphosphate receptor type I (IP3R-I) mRNA were unchanged. In conclusion, renal expression of ACE, AT2-R, and AT1-R mRNA is not mediated by protein leakage. Local intrarenal protein leakage did influence renal TGF-beta mRNA expression.

Traditional cardiac risk factors in individuals with chronic kidney disease

Individuals with chronic kidney disease (CKD) are at increased risk for the development and progression of cardiovascular disease (CVD). The increased risk is due to a higher prevalence of both traditional risk factors as well as nontraditional risk factors. In this review we focus on individuals at all stages of CKD and discuss modifiable traditional risk factors, namely hypertension, dyslipidemia, diabetes mellitus and poor glycemic control, smoking, and physical inactivity. The prevalence of each risk factor and its relationship with CVD is described. Treatment recommendations are provided using evidence available from populations with CKD or evidence extrapolated from the general population when there are insufficient data on individuals with CKD.

Clinical renoprotection trials involving angiotensin II-receptor antagonists and angiotensin-converting-enzyme inhibitors

The leading cause of end-stage renal disease (ESRD) is diabetic nephropathy. Interventions that prevent or palliate renal disease have a positive impact by improving patient care and diminishing healthcare costs. The following review summarizes clinical trals that evaluated treatment in various patient populations including Type 2 diabetic patients with microalbuminuria, subjects with proteinuric non-diabetic nephropathies, and Type 1 and Type 2 diabetic patients with overt nephropathy. These clinical trials have demonstrated that agents directly affecting the renin-angiotensin-aldosterone system provide renal protection beyond that attributable to blood pressure control.

Development of proteinuria or elevated serum creatinine and mortality in HIV-infected women

BACKGROUND

Data on the incidence and prognostic significance of renal dysfunction in HIV disease are limited.

OBJECTIVE

To determine the incidence of proteinuria and elevated serum creatinine in HIV-positive and HIV-negative women and to determine whether these abnormalities are predictors of mortality or associated with causes of death listed on the death certificate in HIV-positive women.

DESIGN

The incidence of proteinuria or elevated serum creatinine and mortality was assessed in a cohort of 885 HIV-positive women and 425 at-risk HIV-negative women.

SETTING

Women from the general community or HIV care clinics in four urban locations in the United States.

OUTCOME MEASURES

Creatinine of >or=1.4 mg/dL, proteinuria 2 or more, or both. Deaths confirmed by a death certificate (92%) or medical record/community report (8%).

RESULTS

At baseline, 64 (7.2%) HIV-positive women and 10 (2.4%) HIV-negative women had proteinuria or elevated creatinine. An additional 128 (14%) HIV-positive women and 18 (4%) HIV-negative women developed these abnormalities over the next (mean) 21 months. Relative hazards of mortality were significantly increased (adjusted relative hazard = 2.5; 95% confidence interval: 1.9-3.3), and there were more renal causes recorded on death certificates (24/92 (26%) vs. 3/127 (2.7%), p<.0001) in HIV-infected women with, compared with those without these renal abnormalities.

CONCLUSIONS

Proteinuria, elevated serum creatinine, or both frequently occurred in these HIV-infected women. These renal abnormalities in HIV-infected women are associated with an increased risk of death after controlling for other risk factors and with an increased likelihood of having renal causes listed on the death certificate. The recognition and management of proteinuria and elevated serum creatinine should be a priority for HIV-infected persons.

Identification of persons at high risk for kidney disease via targeted screening: the NKF Kidney Early Evaluation Program

BACKGROUND

More than 340,000 individuals were receiving renal replacement therapy in the United States at the end of 1999; this number is projected to double by the year 2010. Almost half had a primary diagnosis of diabetes mellitus particularly type 2, and more than one quarter a primary diagnosis of hypertension. Studies have demonstrated effective maneuvers to prevent or delay the rate of progression of kidney disease, and decrease morbidity and mortality. The objective of early diagnosis is early detection of asymptomatic disease at a time when intervention has a reasonable potential to have a positive impact on outcome.

METHODS

In 1997, the National Kidney Foundation launched KEEP trade mark (Kidney Early Evaluation Program), a free community-based screening that targets first order relatives of persons with hypertension, diabetes or kidney disease, and those with a personal history of diabetes or hypertension.

RESULTS

Of the 889 individuals screened in the pilot study, 71.4% had at least one abnormality. The program includes an educational component and referral to a physician for follow-up of abnormal values.

CONCLUSIONS

Targeted screenings are an effective means of identifying persons at risk for kidney disease, and can identify individuals at risk early enough in the course of their disease to allow for effective intervention.

Combination treatment of angiotensin-II receptor blocker and angiotensin-converting-enzyme inhibitor in non-diabetic renal disease (COOPERATE): a randomised controlled trial

BACKGROUND

Present angiotensin-converting-enzyme inhibitor treatment fails to prevent progression of non-diabetic renal disease. We aimed to assess the efficacy and safety of combined treatment of angiotensin-converting-enzyme inhibitor and angiotensin-II receptor blocker, and monotherapy of each drug at its maximum dose, in patients with non-diabetic renal disease.

METHODS

336 patients with non-diabetic renal disease were enrolled from one renal outpatient department in Japan. After screening and an 18-week run-in period, 263 patients were randomly assigned angiotensin-II receptor blocker (losartan, 100 mg daily), angiotensin-converting-enzyme inhibitor (trandolapril, 3 mg daily), or a combination of both drugs at equivalent doses. Survival analysis was done to compare the effects of each regimen on the combined primary endpoint of time to doubling of serum creatinine concentration or end-stage renal disease. Analysis was by intention to treat.

FINDINGS

Seven patients discontinued or were otherwise lost to follow-up. Ten (11%) of 85 patients on combination treatment reached the combined primary endpoint compared with 20 (23%) of 85 on trandolapril alone (hazard ratio 0.38, 95% CI 0.18-0.63, p=0.018) and 20 (23%) of 86 on losartan alone (0.40, 0.17-0.69, p=0.016). Covariates affecting renal survival were combination treatment (hazard ratio 0.38, 95% CI 0.18-0.63, p=0.011), age (1.30, 1.03-2.29, p=0.009), baseline renal function (1.80, 1.02-2.99, p=0.021), change in daily urinary protein excretion rate (0.58, 0.24-0.88, p=0.022), use of diuretics (0.80, 0.30-0.94, p=0.043), and antiproteinuric response to trandolapril (0.81, 0.21-0.91, p=0.039). Frequency of side-effects with combination treatment was the same as with trandolapril alone.

INTERPRETATION

Combination treatment safely retards progression of non-diabetic renal disease compared with monotherapy. However, since some patients reached the combined primary endpoint on combined treatment, further strategies for complete management of progressive non-diabetic renal disease need to be researched.

The renin-angiotensin system and progression of renal disease: from hemodynamics to cell biology

The renal community is faced with an ever increasing number of patients reaching end-stage renal failure. Clinical studies have provided clear evidence that angiotensin-converting enzyme (ACE) inhibitors, and probably also AT1 receptor antagonists, at least in patients suffering from type 2 diabetes, slow disease progression to end-stage renal failure. This protective effect of drugs interfering with the renin-angiotensin system (RAS) are in part independent of reduction in systemic blood pressure, but involve normalization of glomerular hyperperfusion and hyperfiltration, restoration of altered glomerular barrier function, and reduction of stimulated tubular fluid reabsorption. Angiotensin II (ANG II) has emerged in the last decade as a multifunctional cytokine exhibiting many non-hemodynamic properties such as acting as a growth factor and profibrogenic cytokine, and even having proinflammatory properties. This review tries to bridge the classical hemodynamic actions of ANG II in the kidney with the more recently characterized effects of this vasopeptide. Finally, clinical implications are suggested based on data from clinical studies. A thorough understanding of the RAS is important to recognize the potential of nephroprotective strategies through inhibition of its components.