Statins for improving renal outcomes: a meta-analysis

Recognition, pathogenesis, and treatment of different stages of nephropathy in patients with type 2 diabetes mellitus

Nephropathy is a common microvascular complication among patients with type 2 diabetes mellitus and a major cause of kidney failure. It is characterized by albuminuria (≥ 300 mg/d) and a reduced glomerular filtration rate and is often present at the time of diabetes diagnosis after the kidney has been exposed to chronic hyperglycemia during the prediabetic phase. A low glomerular filtration rate (<60 mL/min/1.73 m(2)) is also an independent risk factor for cardiovascular events and death. Detection of diabetic nephropathy during its initial stages provides the opportunity for early therapeutic interventions to prevent or delay the onset of complications and improve outcomes. An intensive and multifactorial management approach is needed that targets all risk determinants simultaneously. The strategy should comprise lifestyle modifications (smoking cessation, weight loss, increased physical activity, and dietary changes) coupled with therapeutic achievement of blood glucose, blood pressure, and lipid goals that are evidence-based. Prescribing decisions should take into account demographic factors, level of kidney impairment, adverse effects, risk of hypoglycemia, tolerability, and effects on other risk factors and comorbidities. Regular and comprehensive follow-up assessments with appropriate adjustment of the therapeutic regimen to maintain risk factor control is a vital component of care, including referral to specialists, when required.

Lipid control in patients with diabetes mellitus

Patients with diabetes mellitus are at increased risk of cardiovascular disease (CVD). Dyslipidemia, an important component of the insulin resistance syndrome and type 2 diabetes, is strongly related to CVD risk and is open to therapeutic intervention. Statins have proved to be safe, very-well tolerated, and highly effective in reducing the levels of LDL cholesterol and apolipoprotein B. Primary and secondary CVD prevention trials have shown that use of statins leads to highly significant reductions in the incidence of major CVD events. A wealth of data on the outcomes of statin therapy is now available to guide clinical practice in the population of patients with type 2 diabetes. Statin therapy in patients with type 1 diabetes seems to have a similar benefit to that seen in patients with type 2 diabetes. However, despite statin therapy, high CVD risk persists in these populations. More-intensive statin therapy produces greater reduction in the incidence of CVD events, but a more-global approach to lipid management is likely to result in further risk reduction. After reductions in the levels of LDL cholesterol and apolipoprotein B, the next target of lipid-lowering therapy is to increase HDL-cholesterol levels, which tend to be low in patients with type 2 diabetes. The most effective HDL-cholesterol-raising agent currently available for use in clinical practice is niacin. Trials with surrogate end points have pointed to the cardiovascular benefit of adding niacin to statin therapy. Large CVD end point trials, which include many patients with diabetes, are underway to test the combination of a statin and niacin versus a statin alone.

Metabolic syndrome, chronic kidney disease, and cardiovascular disease: a dynamic and life-threatening triad

The metabolic syndrome (MS) and chronic kidney disease (CKD) have both become global public health problems, with increasing social and economic impact due to their high prevalence and remarkable impact on morbidity and mortality. The causality between MS and CKD, and its clinical implications, still does remain not completely understood. Moreover, prophylactic and therapeutic interventions do need to be properly investigated in this field. Herein, we critically review the existing clinical evidence that associates MS with renal disease and cardiovascular disease, as well as the associated pathophysiologic mechanisms and actual treatment options.

The role of statins in chronic kidney disease

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality not only amongst the general population, but also in patients with chronic kidney disease (CKD). Persons with CKD are much more likely to die of CVD than to experience kidney failure. Clinical trials have demonstrated that statins are gaining widespread acceptance as a principal therapy for the primary and secondary prevention of atherosclerosis and CVD. In CKD patients the role of statins in primary prevention of CVD remains to be clarified. The absolute benefit of treatment with a statin seems to be greater among nondialysis-dependent-CKD patients. Studies in end-stage renal disease patients on dialysis did not confirm these results. Recently, however, the Study of Heart and Renal Protection (SHARP) has suggested that statins with ezetimibe may be beneficial even in dialysis patients. Clinical studies with statins on proteinuria reduction and renal disease progression have yielded conflicting results. Some studies have shown a prominent reduction in proteinuria, while other studies have shown that statins had no effect or may cause proteinuria at high doses. This review examines the clinical evidence of the observed benefits of kidney function with the use of this drug category in CKD patients.

Potential benefit of statin therapy for dyslipidemia with chronic kidney disease: Fluvastatin Renal Evaluation Trial (FRET)

BACKGROUND

Dyslipidemia is a common complication of chronic kidney disease (CKD) and contributes to cardiovascular morbidity and mortality of CKD patients.

AIM

The aim of the present study was to determine whether fluvastatin, which is mostly characterized by its pleiotropic anti-oxidant effects, has renoprotective effects in dyslipidemic patients with CKD.

METHODS

In 43 dyslipidemic patients with CKD taking fluvastatin 10 mg/day, 20 mg/day or 30 mg/day, renal functions as well as lipid profiles were assessed.

RESULTS

After 3 months of treatment with fluvastatin, LDL-cholesterol level significantly decreased. Serum creatinine level, estimated glomerular filtration rate (eGFR), urinary albumin excretion (UAE), urinary liver-type fatty acid binding protein (L-FABP) level and urinary 8-hydroxydeoxyguanosine (8-OHdG) level did not change in overall patients. However, in patients with microalbuminuria (baseline UAE ≥ 30 mg/g·creatinine; n = 23), the UAE significantly decreased [2.43 ± 0.67 to 1.98 ± 0.80 log(mg/g·creatinine), p = 0.01]. In patients with high L-FABP group (baseline L-FABP ≥ 11 µg/g·creatinine; n = 18), the urinary L-FABP level was significantly decreased (1.52 ± 0.45 to 1.26 ± 0.43 µg/g·creatinine, p < 0.01). In the limited 23 patients with microalbuminuria, the L-FABP level was significantly decreased [1.20 ± 0.62 to 1.03 ± 0.49 log(µg/g·creatinine), p = 0.042], although the LDL-cholesterol level (139 ± 28 to 129 ± 23 mg/dL, p = 0.08) only showed a tendency to decrease. The 8-OHdG level also was significantly decreased (13.6 ± 9.6 to 9.8 ± 3.8 ng/g·creatinine, p = 0.043). In the overall patients, changes in the values for UAE and urinary L-FABP were not correlated with the changes in LDL-levels.

CONCLUSION

Fluvastatin reduces both UAE and the urinary L-FABP level, and thus, has renoprotective effects, independent of its lipid lowering effects in dyslipidemic patients with CKD.

Apolipoprotein E polymorphism and the progression of diabetic nephropathy in type 2 diabetes

BACKGROUND/AIMS

Three different apo E alleles (E2, E3 and E4) produce apo E isoproteins, which regulate the metabolism of lipoproteins. This study investigated the apo E polymorphisms as a prognostic factor for the development of diabetic nephropathy (DN).

METHODS

A total of 525 type 2 diabetic patients were enrolled to participate in this prospective observational study. Apo E gene polymorphisms were analyzed by polymerase chain reaction. The progression of DN was defined as a shift to a higher stage of DN or a doubling of the baseline serum creatinine level by the end of the study.

RESULTS

The mean follow-up period was 42.4 months. The patients whose DN progressed had significantly higher urine albumin/creatinine ratios and fewer used diuretics than those in whom DN did not progress. In the Cox regression analysis, the apo E4 carriers were found to be at greater risk of progression of DN than non-apo E4 carriers (p = 0.007, hazard ratio 2.252). After adjusting for confounding factors, apo E4 carriers remained at increased risk of progression to more severe DN (p = 0.002, hazard ratio 2.820).

CONCLUSION

Our study suggests the apo E4 carrier might serve as a predictor of DN progression in Taiwan.

Protection Against Nephropathy in Diabetes with Atorvastatin (PANDA): a randomized double-blind placebo-controlled trial of high- vs. low-dose atorvastatin(1)

AIMS

To compare the renal effects of low- vs. high-dose atorvastatin in patients with Type 2 diabetes mellitus and optimally managed early renal disease.

METHODS

We compared the 2-year progression of nephropathy in a double-blind randomized controlled trial of atorvastatin 80 mg/day (n = 60) vs. 10 mg/day (n = 59) in patients with Type 2 diabetes with microalbuminuria or proteinuria [mean (sd): age 64 years (10 years); HbA(1c) 7.7% (1.3%), 61 mmol/mol (10 mmol/mol); blood pressure 131/73 mmHg; renin-angiotensin system blocker use > 80%; dual blockade > 67%] recruited from diabetes clinics in Greater Manchester.

RESULTS

Over (mean) 2.1 years of follow-up, the Modification of Diet in Renal Disease estimated glomerular filtration rate declined by 3 ml min(-1) 1.73 m(-2) in the combined group. The mean (95% CI) between-group difference during follow-up was not significant [2.2 ml min(-1) 1.73 m(-2) (-1.1 to 5.4 ml min(-1) 1.73: m(-2) ), P = 0.20] after adjusting for baseline differences in renal function; positive difference favours 80 mg dose. Similarly, there was no significant difference in creatinine clearance by Cockcroft and Gault [2.5 ml/min (-2.4 to 7.3 ml/min), P = 0.32]; serum creatinine/24-h urine collections [4.0 ml/min (-4.8 to 12.7 ml/min), P = 0.38]; cystatin C (P = 0.69); or 24-h urine protein or albumin excretion (P = 0.92; P = 0.93). We recorded no significant between-group differences in deaths or adverse events.

CONCLUSIONS

In patients with Type 2 diabetes with early renal disease, we found no statistical difference in renal function between those taking high- or low-dose atorvastatin over 2 years. We cannot exclude a beneficial effect of < 1.6 ml min(-1) 1.73 m(-2) year(-1) on Modification of Diet in Renal Disease estimated glomerular filtration rate, or if blood pressure management or if renin-angiotensin system blocker use had not been optimized.

Dyslipidemia in chronic kidney disease: are statins still indicated in reduction cardiovascular risk in patients on dialysis treatment?

BACKGROUND

Chronic kidney disease (CKD) is an increasingly health disease all around the world with a high burden of mortality and cardiovascular (CV) morbidity rate. Even when renal replacement therapy is reached, more than half patients die, mainly for CV causes due either to uremia-related cardiovascular risk factors (such as anemia, hyperhomocysteinemia, mineral bone disease-CKD with hyperparathyroidism, oxidative stress, hypoalbuminemia, chronic inflammation, prothrombotic factors) or to traditional ones (age, male gender, diabetes, obesity, hypertension, smoking, insulin levels, family history, dyslipidemia). Among the latter causes dyslipidemia represents one of the major, potentially correctable risk factor.

METHODS AND RESULTS

Statins have demonstrated to effectively and safely reduce cholesterol levels in CKD patients. Here we will examine the effects of statins on CV risk factors in CKD patients and particularly in patients on dialysis treatment, in the light of the unfavorable results of the large trials 4D and AURORA, recently published, underlining the role of malnutrition/inflammation as confounding factor. Probably it will be that only with a real prevention, starting statins even in the early stages of CKD, as indicated by post hoc analysis of large trials, that we will reach results in reducing the mortality rate in CKD patients. In the meanwhile, all the other remediable CV risk factors have to be at the same time corrected.

Event reduction: revisiting why we treat with statins and harnessing current evidence towards optimal therapy

IMPORTANCE OF THE FIELD

Statins are widely accepted as the drugs of choice for achieving increasingly stringent low-density lipoprotein cholesterol (LDL-C) goals for dyslipidemic patients. However, when making treatment decisions, outcomes data from clinical trials are of greater importance than LDL-C-lowering ability.

AREAS COVERED IN THIS REVIEW

This review will provide an update on current lipid treatment guidelines in the context of statin trial evidence, with particular focus on the incremental benefit of more potent statin therapy compared with lower doses. The discussion will also address combination therapy, statin safety, goal attainment and treatment adherence. MEDLINE searches (1966 to July 2010) were performed.

WHAT THE READER WILL GAIN

The reader will gain a comprehensive review of the evidence base for statin therapy and an appreciation of other issues that affect treatment choice.

TAKE HOME MESSAGE

It is important to remember why we need to partner with our patients: to ensure that they are established on, and continue to adhere to, their appropriate evidence-based statin dose with a goal of achieving lipid targets, but more importantly to prevent cardiovascular disease-related morbidity and mortality. We treat patients to reduce clinical cardiovascular events, not just to control lipids and other important risk factors.

Proteinuria in diabetes: bystander or pathway to cardiorenal disease?

The development of albuminuria in diabetics is closely associated with an enhanced risk of renal and cardiovascular disease. However, the role of albuminuria in the pathogenesis of these clinical conditions remains controversial. Whether albuminuria is simply a biomarker or qualifies as a surrogate endpoint for cardiorenal disease has wide-ranging implications from the monitoring and treatment of patients to the design of clinical trials and drug development. We critically review available data to determine whether the association between albuminuria and cardiorenal disease is causative. Current evidence suggests the significance of albuminuria depends on its severity (degree or level) and on the specific clinical outcome under consideration. For diabetic kidney disease, there is convincing epidemiologic and experimental evidence to assign clinical albuminuria status as a surrogate endpoint, but for lower levels of albuminuria (microalbuminuria and normoalbuminuria), the evidence is inconclusive or not available. Albuminuria of any degree is unlikely to be causally related to diabetic cardiovascular disease, but its onset might be useful to identify those subjects at cardiovascular risk and to detect and treat other modifiable risk factors.

Study of Heart and Renal Protection (SHARP): randomized trial to assess the effects of lowering low-density lipoprotein cholesterol among 9,438 patients with chronic kidney disease

BACKGROUND

Lowering low-density lipoprotein (LDL) cholesterol with statin therapy has been shown to reduce the incidence of atherosclerotic events in many types of patient, but it remains uncertain whether it is of net benefit among people with chronic kidney disease (CKD).

METHODS

Patients with advanced CKD (blood creatinine ≥ 1.7 mg/dL [≥ 150 μmol/L] in men or ≥ 1.5 mg/dL [ ≥ 130 μmol/L] in women) with no known history of myocardial infarction or coronary revascularization were randomized in a ratio of 4:4:1 to ezetimibe 10 mg plus simvastatin 20 mg daily versus matching placebo versus simvastatin 20 mg daily (with the latter arm rerandomized at 1 year to ezetimibe 10 mg plus simvastatin 20 mg daily vs placebo). The key outcome will be major atherosclerotic events, defined as the combination of myocardial infarction, coronary death, ischemic stroke, or any revascularization procedure.

RESULTS

A total of 9,438 CKD patients were randomized, of whom 3,056 were on dialysis. Mean age was 61 years, two thirds were male, one fifth had diabetes mellitus, and one sixth had vascular disease. Compared with either placebo or simvastatin alone, allocation to ezetimibe plus simvastatin was not associated with any excess of myopathy, hepatic toxicity, or biliary complications during the first year of follow-up. Compared with placebo, allocation to ezetimibe 10 mg plus simvastatin 20 mg daily yielded average LDL cholesterol differences of 43 mg/dL (1.10 mmol/L) at 1 year and 33 mg/dL (0.85 mmol/L) at 2.5 years. Follow-up is scheduled to continue until August 2010, when all patients will have been followed for at least 4 years.

CONCLUSIONS

SHARP should provide evidence about the efficacy and safety of lowering LDL cholesterol with the combination of ezetimibe and simvastatin among a wide range of patients with CKD.

A randomized clinical trial of hydroxymethylglutaryl- coenzyme a reductase inhibition for acute lung injury (The HARP Study)

RATIONALE

There is no effective pharmacological treatment for acute lung injury (ALI). Statins are a potential new therapy because they modify many of the underlying processes important in ALI.

OBJECTIVES

To test whether simvastatin improves physiological and biological outcomes in ALI.

METHODS

We conducted a randomized, double-blinded, placebo-controlled trial in patients with ALI. Patients received 80 mg simvastatin or placebo until cessation of mechanical ventilation or up to 14 days. Extravascular lung water was measured using thermodilution. Measures of pulmonary and nonpulmonary organ function were assessed daily. Pulmonary and systemic inflammation was assessed by bronchoalveolar lavage fluid and plasma cytokines. Systemic inflammation was also measured by plasma C-reactive protein.

MEASUREMENTS AND MAIN RESULTS

Sixty patients were recruited. Baseline characteristics, including demographics and severity of illness scores, were similar in both groups. At Day 7, there was no difference in extravascular lung water. By Day 14, the simvastatin-treated group had improvements in nonpulmonary organ dysfunction. Oxygenation and respiratory mechanics improved, although these parameters failed to reach statistical significance. Intensive care unit mortality was 30% in both groups. Simvastatin was well tolerated, with no increase in adverse events. Simvastatin decreased bronchoalveolar lavage IL-8 by 2.5-fold (P = 0.04). Plasma C-reactive protein decreased in both groups but failed to achieve significance in the placebo-treated group.

CONCLUSIONS

Treatment with simvastatin appears to be safe and may be associated with an improvement in organ dysfunction in ALI. These clinical effects may be mediated by a reduction in pulmonary and systemic inflammation. Clinical trial registered with www.controlled-trials.com (ISRCTN70127774).

Statins for prevention of contrast-induced nephropathy in patients undergoing non-emergent percutaneous coronary intervention

AIM

Oxidative stress and ischaemia are suggested as possible mechanisms of contrast-induced nephropathy (CIN). Statins may offer renoprotection in both acute and chronic kidney diseases because of their antioxidant and anti-inflammatory properties. We investigated whether use of statins before non-emergent percutaneous coronary intervention (PCI) reduces the incidence of CIN.

METHODS

We retrospectively evaluated 540 consecutive adult patients who underwent non-emergent PCI over a 3 year period at a tertiary care centre. CIN was defined as 25% or 44 mmol/L increase from baseline creatinine at 48-72 h. In addition, we classified patients based on Mehran score for risk of development of CIN and analysed the effect of statins.

RESULTS

Three-hundred and fifty-three patients met inclusion criteria. Two-hundred and thirty-nine patients were taking statins before PCI and 114 were not. Baseline characteristics were similar for both groups. CIN occurred in 75 patients (21.2%). There was a higher incidence of CIN in patients on statins as compared with patients not on statins (24.7% vs 14%; 95% CI: 1.09-3.67; P = 0.02). However, propensity-based adjustment for receipt of statins revealed no significant differences in CIN between both groups (OR: 1.6; 95% CI: 0.87-3.22; P = 0.12). Multivariate logistic regression revealed Mehran score to be independently predictive of CIN. None of the patients who developed CIN required dialysis.

CONCLUSIONS

Statin use before non-emergent PCI is not associated with reduction in CIN. Further randomized controlled trials based on proper risk adjustment for development of CIN are needed.

Membranous nephropathy in children: clinical presentation and therapeutic approach

The approach to the pediatric patient with membranous nephropathy (MN) can be challenging to the practitioner. The clinical presentation of the child with this histologic entity usually involves some degree of proteinuria ranging from persistent, subnephrotic-ranged proteinuria to overt nephrotic syndrome. Patients often have accompanying microscopic hematuria and may have azotemia or mild hypertension. Children presenting with nephrotic syndrome are often steroid resistant; as such, their biopsy for steroid-resistant nephrotic syndrome results in the diagnosis of MN. The practitioner treating MN in the pediatric patient must weigh the risks of immunosuppressive therapy against the benefits. In general, the child with subnephrotic proteinuria and normal renal function can likely be treated conservatively with angiotensin blockade (angiotensin-converting enzyme inhibitors or angiotensin receptor blockers) without the need for immunosuppressive therapy. Those with nephrotic syndrome are usually treated with steroids initially and often followed by alkylating agents (cyclophosphamide or chlorambucil). Calcineurin inhibitors may also be useful, but the relapse rate after their discontinuation remains high. The absence of controlled studies in children with MN makes treatment recommendations difficult, but until they are available, using the patient's clinical presentation and risk of disease progression appears to be the most prudent approach.

Effects of fungal statins on high-glucose-induced mouse mesangial cell hypocontractility may involve filamentous actin, t-complex polypeptide 1 subunit beta, and glucose regulated protein 78

Glomerular hyperfiltration is associated with mesangial cell hypocontractility. How 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (statins) influence mesangial cell contraction is unclear. We investigated the effect of statins on mesangial cell hypocontractility and identified candidate proteins and filamentous/globular (F/G)-actin involved in this process. A high-glucose-induced mouse mesangial cell hypocontractility model was treated with fungal statins, simvastatin (Sim), lovastatin (Lov), and pravastatin (Pra). The optimum statin dose was determined by an 3-(4,5-Dimethylthiazol-2-Yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay and then applied to a cell model. A 2-dimensional gel/matrix-assisted laser desorption/ionization time-of-flight mass spectrometer analysis was used to evaluate protein expression cells incubated in the presence of a normal level of glucose (N), a high level of glucose (H), and a high level of glucose plus Sim (H + S). Candidate proteins were analyzed. Finally, the ratio of F/G actin in groups N, H, and H+S was evaluated. The MTT assay showed that Sim and Lov exerted dose- and time-related inhibition of proliferation of mesangial cells at N, but Pra had no effect. The optimum doses selected for Sim was 1 microM and for Lov was 3 microM, which were 1 increment before significant proliferation inhibition. Both doses reversed cell hypocontractility significantly, but Sim was chosen for further proteomic and F/G actin analyses. Proteomic analysis of groups N, H, and H + S showed that 18 proteins were involved in hypocontractility. These proteins were grouped and analyzed based on their known functions. Two selected proteins, TCP-1beta and GRP78, that were upregulated and downregulated, respectively, were confirmed by Western blot and immunohistochemistry. In regard to the F/G actin, group H had a significantly lower ratio than that of group N, and group H + S returned to a level similar to that of group N. In conclusion, Sim and Lov both seem to reverse mesangial cell hypocontractility. The process of Sim reversal of mesangial cell hypocontractility may involve F-actin, TCP-1beta, and GRP78.

Early intervention strategies to lower cardiovascular risk in early nephropathy: focus on dyslipidemia

Patients with chronic kidney disease (CKD) are at high cardiovascular risk and we can consider them to have a risk equivalent to coronary heart disease, putting them into the high-risk category. A mixed dyslipidemia with high triglyceride levels; low high-density lipoprotein (HDL) levels; and small, dense low-density lipoprotein (LDL) particles is a common pattern in patients with CKD, contributing to their high cardiovascular disease (CVD) risk. A treatment strategy to reduce LDL cholesterol to the current high-risk category goals reduces risk similar to patients without CKD. Emerging evidence suggests that targeting non-HDL cholesterol can have the potential to bring about further CVD risk reduction. Non-HDL cholesterol should be a secondary target for all patients with CKD. Further studies are needed to determine the magnitude of the risk reduction we can expect to gain by targeting non-HDL cholesterol and the most effective way to treat this target.

Medication issues in older individuals with CKD

Older US adults bear a substantial burden of chronic disease and take an average of five prescription and non-prescription medications per day. Recent data suggest that over 20% of older adults have chronic kidney disease (CKD) as defined by an impaired glomerular filtration rate. These individuals often have multiple comorbidities, including diabetes, hypertension, and cardiovascular disease. Although patients with CKD may receive substantial benefits from prescribed medications, they are also at high risk for adverse drug events and polypharmacy. In this review, we outline the risks and benefits of medication use in the CKD population as a specific case within geriatric pharmacoepidemiology as a framework.

Renal lipid metabolism and lipotoxicity

PURPOSE OF REVIEW

Lipid accumulation in nonadipose tissues is increasingly recognized to contribute to organ injury through a process termed lipotoxicity, but whether this process occurs in the kidney is still uncertain. This article briefly summarizes the normal role of lipids in renal physiology and the current evidence linking excess lipids and lipotoxicity to renal dysfunction.

RECENT FINDINGS

Evidence suggesting that renal lipid accumulation and lipotoxicity may lead to kidney dysfunction has mounted significantly over recent years. Abnormal renal lipid content has been described in a number of animal models and has been successfully manipulated using pharmacologic or genetic strategies. There is some heterogeneity among studies with regard to the mechanisms, consequences, and localization of lipid accumulation in the kidney, explainable at least in part by inherent differences between animal models. The relevance of these findings for human pathophysiology remains to be established.

SUMMARY

Current knowledge on renal lipid physiology and pathophysiology is insufficient, but provides a strong foundation and incentive for further exploration. The future holds significant challenges in this area, especially with regard to applicability of research findings to the human kidney in vivo, but also the opportunity to transform our understanding of an array of kidney disorders.

Effect of pravastatin on kidney function and urinary protein excretion in autosomal dominant polycystic kidney disease

OBJECTIVE

Autosomal dominant polycystic kidney disease (ADPKD) is progressive, resulting in end-stage kidney failure in most patients. Experimental and clinical studies have suggested that statins may slow the progression of chronic kidney disease in general and ADPKD specifically.

MATERIAL AND METHODS

This randomized open-label clinical trial was conducted to assess the effect of pravastatin 20 mg on kidney function and urinary protein excretion in patients with ADPKD. Sixty patients were initially recruited but 49 of these received either pravastatin 20 mg or no treatment for 2 years. Trial visits were conducted every 3 months, assessing kidney function by estimated glomerular filtration rate and 24 h urine creatinine clearance and urinary protein excretion.

RESULTS

There were no significant (p > 0.05) changes in markers of kidney function or urinary protein excretion between groups over the 2 years despite a significant fall in total serum cholesterol in pravastatin-treated patients (p = 0.029).

CONCLUSION

This trial found that taking 20 mg pravastatin for 2 years had no significant effect on kidney function or urinary protein excretion in patients with ADPKD. The lack of statistical power limits the external validity of these findings. A larger, longer duration study using a higher dose of a more potent statin is required.

Association of statin use and development of renal dysfunction in type 2 diabetes--the Hong Kong Diabetes Registry

AIM

Dyslipidaemia may be a risk factor for diabetic kidney disease. We examined prospectively association between the use of statins and development of renal dysfunction in type 2 diabetes.

METHODS

A consecutive cohort of 5264 diabetic patient recruited between 1996 and 2005 underwent detailed assessments. Renal dysfunction was defined as first estimated glomerular filtration rate <60 ml/min/1.73 m(2), or, the first hospitalisation with a diagnosis of renal disease as coded by the International Classification of Disease, Ninth Revision. Drug use was quantified using the proportion of exposure time from baseline to event/death/censored time, as appropriate.

RESULTS

In this cohort (male: 47.3%, median age: 55 years, median duration of diabetes: 6.0 years), none had renal dysfunction at baseline. During a median follow-up period of 4.9 (quartiles: 2.77, 7.04) years, 703 patients (13.4%) developed renal dysfunction, 1275 patients (22.2%) were exposed to statins. After controlling for baseline risk factors, multivariable adjusted hazard ratio of statin use for development of renal dysfunction was 0.32 (95% CI 0.21-0.50, p<0.0001).

CONCLUSION

Use of statins was associated with reduced risk of developing renal dysfunction in type 2 diabetes and this association was independent of baseline risk factors.

Early statin use is an independent predictor of long-term graft survival

Background. Statin use in renal transplantation has been associated with a lower risk of patient death but not with an improvement of graft functional survival. The aim of this study is to evaluate the effect of statin use in graft survival, death-censored graft survival and patient survival using the data recorded on the Spanish Late Allograft Dysfunction Study Group.

Patients and methods. Patients receiving a renal allograft in Spain in 1990, 1994, 1998 and 2002 were considered. Since the mean follow-up in the 2002 cohort was 3 years, statin use was analysed considering its introduction during the first year or during the initial 2 years after transplantation. Univariate and multivariate Cox regression analyses with a propensity score for statin use were employed to analyse graft survival, death-censored graft survival and patient survival.

Results. In the 4682 evaluated patients, the early statin use after transplantation significantly increased from 1990 to 2002 (12.7%, 27.9%, 47.7% and 53.0%, P < 0.001). Statin use during the first year was not associated with graft or patient survival. Statin use during the initial 2 years was associated with a lower risk of graft failure (relative risk [RR] = 0.741 and 95% confidence interval [CI] = 0.635–0.866, P < 0.001) and patient death (RR = 0.806 and 95% CI = 0.656–0.989, P = 0.039). Death-censored graft survival was not associated with statin use during the initial 2 years.

Conclusion. The early introduction of statin treatment after transplantation is associated with a significant decrease in late graft failure due to a risk reduction in patient death.

New pharmacological treatments for improving renal outcomes in diabetes

Diabetic nephropathy is the most common and most rapidly growing cause of end-stage renal failure in developed countries. Diabetic nephropathy results from complex interactions between genetic, metabolic and hemodynamic factors. Improvements in our understanding of the pathogenesis of fibrosis associated with diabetic kidney disease have led to the identification of several novel targets for the treatment of diabetic nephropathy. Albuminuria is a useful clinical marker of diabetic nephropathy, as it can be used to predict a decline in renal function. A reduction in albuminuria might not, however, be reflective of a protective effect of therapies focused on ameliorating renal fibrosis. Although new strategies for slowing down the progression of several types of renal disease have emerged, the challenge of arresting the relentless progression of diabetic nephropathy remains. In this Review, we discuss novel pharmacological approaches that aim to improve the renal outcomes of diabetic nephropathy, including the use of direct renin inhibitors and statins. We also discuss the promise of using antifibrotic agents to treat diabetic nephropathy. The need for novel biomarkers of diabetic nephropathy is also highlighted.

Lipids in chronic kidney disease

Patients with chronic kidney disease (CKD) develop premature cardiovascular disease. In the general population (without CKD), there are strong associations between cholesterol fractions and the risk of coronary disease and weaker associations with stroke. Randomised trials in the general population demonstrate that lowering blood cholesterol (chiefly with a statin) reduces the risk of vascular events. Patients with CKD differ significantly from the general population. They have markedly disturbed lipid metabolism manifesting as elevated triglyceride concentrations, reduced HDL cholesterol concentrations and a preponderance of small, dense LDL particles that are potentially more atherogenic; the observed association between lipids and vascular disease is bizarre, and is confounded by co-morbidity; the nature of the vascular disease appears less strongly associated with classical atherosclerosis. Randomised trials are required to determine the relevance of blood lipids to the development of vascular disease in CKD patients, but the results of such studies have been inconclusive to date. CKD patients are at risk of end-stage renal disease. Lipids may be involved in the progression of renal disease. Modifying them may delay the progression of CKD. The current data are based on effects on markers of progression (e.g. proteinuria). The ongoing SHARP (Study of Heart and Renal Protection) trial should provide reliable information about the effects of statins on both vascular and renal risk.

Early recognition and prevention of chronic kidney disease

Chronic kidney disease is a common disorder and its prevalence is increasing worldwide. Early diagnosis on the basis of presence of proteinuria or reduced estimated glomerular filtration rate could permit early intervention to reduce the risks of cardiovascular events, kidney failure, and death that are associated with chronic kidney disease. In developed countries, screening for the disorder is most efficient when targeted at high-risk groups including elderly people and those with concomitant illness (such as diabetes, hypertension, or cardiovascular disease) or a family history of chronic kidney disease, although the role of screening in developing countries is not yet clear. Effective strategies are available to slow the progression of chronic kidney disease and reduce cardiovascular risk. Treatment of high blood pressure is recommended for all individuals with, or at risk of, chronic kidney disease. Use of angiotensin-converting-enzyme inhibitors or angiotensin-receptor blockers is preferred for patients with diabetic chronic kidney disease or those with the proteinuric non-diabetic disorder. Glycaemic control can help prevent the onset of early stages of chronic kidney disease in individuals with diabetes. Use of statins and aspirin is beneficial for most patients with chronic kidney disease who are at high cardiovascular risk, although research is needed to ascertain how to best prevent cardiovascular disease in this cohort. Models of care that facilitate delivery of the many complex aspects of treatment simultaneously could enhance management, although effects on clinical outcomes need further assessment. Novel clinical methods to better identify patients at risk of progression to later stages of chronic kidney disease, including kidney failure, are needed to target management to high-risk subgroups.

Slowing the progression of chronic kidney disease

Progression of chronic kidney disease can be slowed by careful management of risk factors. The most effective treatments are aggressive blood pressure control, renin-angiotensin system inhibition in proteinuric patients and tight glycaemic control in diabetics. Patients should be educated to avoid nephrotoxins and maintain a healthy lifestyle.

Disorders of lipid metabolism and chronic kidney disease in the elderly

The growing population of elderly with chronic kidney disease (CKD) is at greater risk for cardiovascular disease given an independent risk of CKD, as well as from added dyslipidemia of aging and renal dysfunction. Changes in lipid metabolism with more isodense and high-dense, triglyceride-rich particles, low high-density lipoprotein cholesterol, and increased triglyceride levels occur with CKD and aging, which are noted to have significant atherogenic potential. In addition, lipid abnormalities may lead to the progression of CKD. Cardiovascular mortality in the end-stage renal disease population is more than 10 times higher than the general population. Treatment of dyslipidemia in the general population suggests important benefits both in reducing cardiovascular risk and in the prevention of cardiovascular disease. Secondary analyses of elderly subgroups of various large prospective studies with statins suggest treatment benefit with statin use in the elderly. Similarly limited data from secondary analyses of CKD subgroups of larger prospective trials using statins also suggest a possible benefit in cardiovascular outcomes and the progression of kidney disease. However, randomized trials have yet to confirm similar benefits and targets of treatment for dyslipidemia in the elderly with CKD and end-stage renal disease. Treatment in the elderly with CKD should be individualized and outweigh risks of side effects and drug-drug interactions. There is a need for further specific investigation of dyslipidemia of CKD in the aging population in relation to renal disease progression and cardiovascular outcome.

Can we slow the progression of chronic kidney disease?

PURPOSE OF REVIEW

Childhood chronic kidney disease usually progresses towards end-stage renal failure once a critical impairment of renal function has occurred. This process is largely independent of the underlying renal disease. Recent clinical trials have provided evidence that the progressive course of chronic kidney disease can be slowed substantially by pharmacological intervention.

RECENT FINDINGS

Hypertension and proteinuria are the most important independent risk factors for renal disease progression in both adult and pediatric nephropathies. Pharmacological blockade of the renin-angiotensin system provides efficient control of blood pressure and proteinuria, and superior long-term renoprotection compared with other antihypertensive agents. Recent pediatric evidence supports the renoprotective efficacy of tight blood pressure control aiming for the low-normal range. In addition, promising preliminary findings suggest an additional renoprotective potential by correction of metabolic acidosis and hyperuricemia and by administration of antiproliferative and antioxidative drugs.

SUMMARY

Pharmacological renoprotection currently focuses on antihypertensive and antiproteinuric treatment by blockade of the renin-angiotensin system. Intensified blood pressure control can improve 5-year renal survival by 35% in children with chronic kidney disease. Additional complementary strategies under current clinical evaluation bear potential to improve renal survival even further.

Transplantation in diabetic kidney failure patients: modalities, outcomes, and clinical management

Diabetes mellitus (DM) is a common and devastating disease, affecting up to 19.3 million Americans. It is the leading cause of chronic kidney disease (CKD) and end-stage renal disease (ESRD) in the United States. Diabetic patients with ESRD have a high incidence of cardiovascular disease and death. For those kidney transplant patients with no history of DM prior to transplantation, the development of new onset diabetes after transplantation (NODAT) also poses a serious threat to both graft and patient survival. Kidney transplantation is the best renal replacement option for diabetic ESRD and has the potential to halt the progression of cardiovascular diseases. Early referral for transplant evaluation is essential for pre-emptive or early kidney transplantation in this cohort of patients. In type 1 DM patients with ESRD, simultaneous pancreas and kidney transplantation (SPK) should be encouraged; and in patients facing prolonged waiting time for SPK transplantation but with an available living donor, living donor kidney transplantation followed by pancreas after kidney transplantation (PAK) is a suitable alternative. Islet transplantation in type 1 diabetics is deemed experimental by Medicare, and easy access to this modality remains restricted to qualified patients enrolled in clinical trials or with private insurance. The optimal management of kidney transplant patients with pre-existent DM or NODAT involves a multi-pronged approach consisting of pharmacological and nonpharmacological intervention to address all potential cardiovascular risk factors such as glycemic and lipid control, blood pressure control, weight loss, and smoking cessation. Finally, re-transplantation should be recommended in suitable kidney transplant patients when the kidney allograft demonstrates continuous and progressive decline in function.

Reversibility of renal injury with cholesterol lowering in hyperlipidemic diabetic mice

Hyperlipidemia is a risk factor for development and progression of diabetic nephropathy. However, it is not known if reduction of hyperlipidemia is protective against progression of disease. The goal of this study was to determine if reduction of hypercholesterolemia could limit progression of diabetic nephropathy. Diabetic and nondiabetic LDL receptor deficient (LDLR(-/-)) mice were fed diets containing either no cholesterol (0%) or high cholesterol (0.12%) for 36 weeks. One group each of diabetic and nondiabetic mice were fed the high-cholesterol diet for 26 weeks then changed to the 0% cholesterol diet for the last 10 weeks. Consumption of the high-cholesterol diet exacerbated the development of diabetic nephropathy with elevations in urine albumin excretion, glomerular and renal hypertrophy, and mesangial matrix expansion. Increased glomerular lipid and apolipoprotein B accumulation was found in diabetic mice that consumed the 0.12% cholesterol diet compared with other groups. However, diabetic mice that changed from the high-cholesterol diet to the 0% cholesterol diet for the last 10 weeks had lower urine albumin excretion and mesangial matrix expansion compared with mice that consumed the 0.12% cholesterol diet throughout. This suggests that hyperlipidemia causes continuous renal injury, and that lowering cholesterol levels by dietary means can improve renal function in diabetic LDLR(-/-) mice.

Effect of atorvastatin on aldosterone production induced by glucose, LDL or angiotensin II in human renal mesangial cells

Nephropathy is a major complication of diabetes mellitus, thus development of rational therapeutic means is critical for improving public health. It was previously reported that human mesangial cells locally produced aldosterone, a steroid hormone that plays an important role in the development of diabetic nephropathy. The present experiments clarified the effect of glucose, LDL and angiotensin II, the molecules frequently elevated in patients with diabetic nephropathy, on aldosterone production in human primary mesangial cells. These cells expressed the CYP11B2 mRNA, a rate-limiting enzyme in the aldosterone biosynthesis. LDL and angiotensin II stimulated CYP11B2 mRNA expression in these cells, while a high concentration of glucose, angiotensin II and/or LDL increased aldosterone production. Importantly, atorvastatin (CAS 134523-03-8), an HMG-CoA (3-hydroxy-3-methylglutaryl-coenzyme A) reductase inhibitor, strongly suppressed their effects on aldosterone production. Atorvastatin also suppressed positive effects of these compounds on the mRNA expression of the angiotensin II receptor type 1, thus atorvastatin exerted its negative effect in part through changing expression of this receptor. Since elevated levels of glucose and LDL, and increased action of the renin-angiotensin-aldosterone system is known to participate in the progression of diabetic nephropathy, it is speculated that the mesangial endocrine system that produces aldosterone locally is a promising therapeutic target for diabetic nephropathy where HMG-CoA reductase inhibitors provide a beneficial effect.

Residual microvascular risk in diabetes: unmet needs and future directions

The burden of microvascular disease in patients with type 2 diabetes mellitus continues to escalate worldwide. Current standards of care reduce but do not eliminate the risk of diabetic retinopathy, nephropathy or neuropathy in these patients. Correction of atherogenic dyslipidemia, which is characterized by elevated triglyceride levels and low levels of HDL cholesterol, might provide additional benefit. Whereas promising data have been published with respect to fibrate therapy for maculopathy, fenofibrate for diabetic retinopathy, and statin or fibrate therapy for diabetic nephropathy, further studies are warranted to define optimal management strategies for reducing the residual microvascular risk. Such strategies are especially relevant in cases of diabetic peripheral neuropathy, where even optimal care fails to affect disease progression. Identification of those factors that are most relevant to residual diabetes-related microvascular risk is a priority of an ongoing multinational epidemiological study. In this Review, we highlight an urgent need to address the issue of microvascular residual risk in patients with or at risk of type 2 diabetes mellitus.

Glomerulonephritis and managing the risks of chronic renal disease

The rising global burden of chronic renal disease, the high cost of providing renal replacement therapies, and renal disease also being a risk factor for cardiovascular disease is increasing focus on renal disease prevention. This article focuses on the aspects of renal disease (specifically poststreptococcal glomerulonephritis [PSGN] and chronic kidney disease [CKD]) in Indigenous populations in Australia, New Zealand, Canada, and the United States that diverge from those typically seen in the general population of those countries. The spectrum of renal and many other diseases seen in Indigenous people in developed countries is similar to that seen in developing countries. Diseases like PSGN that have largely disappeared in developed countries still occur frequently in Indigenous people. CKD during the childhood years is due to congenital anomalies of the kidney and urinary tract in up to 70% of cases and occurs later in polycystic kidney disease and childhood-onset diabetes. Several risk factors for CKD in adulthood are already present in childhood.