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

Proteinuria in sarcoidosis: Prevalence and risk factors in a consecutive outpatient cohort

Introduction: While sarcoidosis has been recognized as a potential cause of proteinuria, no study has systematically evaluated the prevalence and risk factors for proteinuria in sarcoid patients. Methods: Consecutive sarcoid patients followed in a university clinic were identified prospectively. All patients with spot urine protein-to-creatinine ratio (UPCR) between 11-2012 and 07-2015 were included in the analysis. Proteinuria was defined as a spot UPCR equal to or exceeding 0.3 mg/mg. The primary goal of the study was to determine the prevalence of proteinuria in this sarcoidosis cohort. Results: Our study cohort consisted of 190 sarcoidosis patients (65% female, 82% white, mean age of 53 years (range 24-88)). Proteinuria was present in 14/190 (7%) of this cohort. Only5/190 patients (2.5%) had proteinuria who did not have a risk factor for proteinuria. Estimating the 24-hour urine protein excretion by extrapolating from the spot UPCR, proteinuria was moderate in amount (mean 1.60, range 0.32-5.06 mg/mg). Proteinuric patients received a lower mean daily dose of corticosteroids compared to those without proteinuria (0 mg vs 4.7 mg of prednisone); however, this difference did not reach statistical significance (p = 0.20). Conclusion: Our study found proteinuria in 7% of the 190 sarcoid patients. More than half of the patients with proteinuria had a known risk factor for proteinuria other than sarcoidosis. Proteinuria is uncommon in sarcoidosis, and, when it occurs, it should not be assumed that sarcoidosis is the cause without investigating alternative causes of proteinuria. (Sarcoidosis Vasc Diffuse Lung Dis 2017; 34: 142-148).

Validation of the Kidney Failure Risk Equation in Manitoba

Background:

Patients with chronic kidney disease (CKD) are at risk to progress to kidney failure. We previously developed the Kidney Failure Risk Equation (KFRE) to predict progression to kidney failure in patients referred to nephrologists.

Objective:

The objective of this study was to determine the ability of the KFRE to discriminate which patients will progress to kidney failure in an unreferred population.

Design:

A retrospective cohort study was conducted using administrative databases.

Setting:

This study took place in Manitoba, Canada.

Measurements:

Age, sex, estimated glomerular filtration rate (eGFR), and urine albumin-to-creatinine ratio (ACR) were measured.

Methods:

We included patients from the Diagnostic Services of Manitoba database with an eGFR <60 mL/min/1.73 m² and ACR measured between October 2006 and March 2007. Five-year kidney failure risk was predicted using the 4-variable KFRE and compared with treated kidney failure events from the Manitoba Renal Program database. Sensitivity and specificity for KFRE risk thresholds (3% and 10% over 5 years) were compared with eGFR thresholds (30 and 45 mL/min/1.73 m²).

Results:

Of 1512 included patients, 151 developed kidney failure over the 5-year follow-up period. The 4-variable KFRE showed a superior prognostic discrimination compared with eGFR alone (area under the receiver operating characteristic curve [AUROC] values, 0.90 [95% confidence interval {CI}: 0.88-0.92] for KFRE vs 0.78 [95% CI: 0.74-0.83] for eGFR). At a 3% threshold over 5 years, the KFRE had a sensitivity of 97% and a specificity of 62%. At 10% risk, sensitivity was 86%, and specificity was 80%.

Limitations:

Only 11.7% of stage 3-5 CKD patients had simultaneous ACR measurement. The KFRE does not account for other indications for referral such as suspected glomerulonephritis, polycystic kidney disease, and recurrent stone disease.

Conclusions:

The KFRE has been validated in a population with a demographic and referral profile heretofore untested and performs well at predicting 5-year risk of kidney failure in a population-based sample of Manitobans with CKD stages 3 to 5. Thresholds of 3% and 10% over 5 years are sensitive, specific, and can be used in clinical decision making. Further testing of the 4-variable KFRE and these thresholds in clinical practice should be considered.

The Impact of Renin-Angiotensin System Blockade on Renal Outcomes and Mortality in Pre-Dialysis Patients with Advanced Chronic Kidney Disease

Renin-angiotensin-system (RAS) blockade is thought to slow renal progression in patients with chronic kidney disease (CKD). However, it remains uncertain if the habitual use of RAS inhibitors affects renal progression and outcomes in pre-dialysis patients with advanced CKD. In this multicenter retrospective cohort study, we identified 2,076 pre-dialysis patients with advanced CKD (stage 4 or 5) from a total of 33,722 CKD patients. RAS blockade users were paired with non-users for analyses using inverse probability of treatment-weighted (IPTW) and propensity score (PS) matching. The outcomes were renal death, all-cause mortality, hospitalization for hyperkalemia, and interactive factors as composite outcomes. RAS blockade users showed an increased risk of renal death in PS-matched analysis (hazard ratio [HR], 1.381; 95% CI, 1.071–1.781; P = 0.013), which was in agreement with the results of IPTW analysis (HR, 1.298; 95% CI, 1.123–1.500; P < 0.001). The risk of composite outcomes was higher in RAS blockade users in IPTW (HR, 1.154; 95% CI, 1.016–1.310; P = 0.027), but was marginal significance in PS matched analysis (HR, 1.243; 95% CI, 0.996–1.550; P = 0.054). The habitual use of RAS blockades in pre-dialysis patients with advanced CKD may have a detrimental effect on renal outcome without improving all-cause mortality. Further studies are warranted to determine whether withholding RAS blockade may lead to better outcomes in these patients.

A Comparative Effectiveness Study of Renal Parameters Between Imidapril and Amlodipine in Patients with Hypertension: A Retrospective Cohort Study

Introduction

Imidapril is an angiotensin converting enzyme inhibitor (ACEI) that is frequently used as an antihypertensive drug in Japan. Although ACEIs are known to have adverse effects of decreasing glomerular filtration rate (GFR) and causing hyperkalemia, there are very few clinical data on the long-term effect of imidapril on glomerular function. We conducted a retrospective cohort study using a clinical database to evaluate and compare the long-term effects of imidapril and amlodipine on renal parameters in Japanese hypertensive patients in routine clinical practice.

Methods

We identified cohorts of new users of imidapril (n = 57) and a propensity score-matched group with an equal number of new users of amlodipine (n = 57). We used a multivariable regression model to evaluate and compare the effects of the drugs on laboratory parameters including serum levels of creatinine, potassium, sodium, blood urea nitrogen, and estimated GFR (eGFR) between imidapril users and amlodipine users up to 12 months after the initiation of study drug administration. The mean exposure of imidapril and amlodipine was 226.2 and 235.2 days, respectively.

Results

We found a significant increase of serum creatinine and potassium levels and a decrease of eGFR in imidapril users from the baseline period to the exposure period. The reduction of eGFR and the increase of serum creatinine and potassium levels in imidapril users were significantly greater than those in amlodipine users.

Conclusions

Our study showed that imidapril decreased eGFR and increases the serum levels of creatinine and potassium compared with amlodipine, at least during 1 year of administration.

Awareness of physicians in Jordan about the treatment of high blood pressure according to the seventh report of the Joint National Committee (JNC VII)

Background

Control of blood pressure remains suboptimal worldwide. High rates of undiagnosed and untreated hypertensive patients raise the need of searching for the basis of this situation among prescribing physicians.

Aim

To evaluate the awareness of medical residents and practicing physicians in Jordan about the treatment of high blood pressure according to the seventh report of the Joint National Committee (JNC VII).

Method

A written questionnaire was distributed to 200 physicians from different areas of Jordan during the period from November 2005 till February 2006. Recruitment of physicians in this study was in general, military, private hospitals and in clinics. A rigorously developed questionnaire on changes seen in JNC VII, target blood pressure goals, and the treatment of high blood pressure options was administered by trained medical personnel.

Results

One hundred and forty five physicians (72.5%) consented to complete the questionnaire. The practices of recent graduates from medical school were not better than those of older graduates. As a general rule, physicians in Jordan under treat high blood pressure.

Conclusion

Our findings highlight the need for the revision of the teaching curricula in medical schools with regard to the management of hypertension, as well as the initiation of a widespread and intensive continuing medical education for all physicians involved in the management of patients with hypertension. Particular efforts are needed to encourage the use of low-cost thiazides and the use of angiotension converting enzyme inhibitors in heart failure patients and other compelling indications.

Relative antihypertensive and glomeruloprotective efficacies of enalapril and candesartan cilexetil in the remnant kidney model

The present studies were performed to investigate whether the differences described between the two modalities for interruption of the renin-angiotensin-aldosterone system (RAAS), angiotensin-converting enzyme inhibitors (ACE-I) and angiotensin AT 1receptor antagonists (AIIA) result in differences in renoprotective efficacy in the rat remnant kidney model. Male Sprague-Dawley rats with an initial body weight of 225—300 g, underwent 5/6 renal ablation and had radiotransmitters installed for radiotelemetric blood pressure (BP) measurements, owing to the known limitations of periodic tail-cuff BP measurements to adequately reflect ambient BP profiles. After renal ablation surgery, the rats received no treatment (n=10); enalapril (n=11) or candesartan (n=9) after the first week, both administered initially at a dose of 50 mg/l of drinking water (~10 mg/kg). However, the dose of candesartan had to be reduced to 10—25 mg/l in 4/9 rats to avoid excessive hypotension. Both enalapril and candesartan produced significant reductions in average systolic BP during the subsequent approximately six weeks of observations as compared with untreated rats (187±4 mmHg, p<0.001), but candesartan was significantly more effective at these relative doses (121±3 vs. 133±4 mmHg, p<0.05). At approximately seven weeks, serum creatinine and proteinuria were measured before sacrifice for morphologic assessment of percentage glomerulosclerosis (GS). Despite the described differences between ACE-I and AIIA after acute administration, the percentage GS was reduced similarly by enalapril (down to 6.8±2.8%) and candesartan (down to 2.9±1.5%) as compared with untreated rats (37.2±4.3%). Moreover, GS in individual animals paralleled the BP reductions achieved. Proteinuria was reduced in parallel to the decrease in % GS. These data indicate that, at least in the 5/6 renal ablation model, RAAS blockade by either ACE-I or AIIA provides protection by BPdependent rather than BP-independent mechanisms. This may reflect the primarily hypertensive pathogenesis of GS in this model, and the fact that hypertension is also very angiotensin II-dependent in this model. Thus, these data suggest that models other than the 5/6 ablation model may be more appropriate to demonstrate the BP-independent protective effects of RAAS blockade.

Effects of Vitamin D Receptor Activation and Dietary Sodium Restriction on Residual Albuminuria in CKD: The ViRTUE-CKD Trial

Reduction of residual albuminuria during single-agent renin-angiotensin-aldosterone blockade is accompanied by improved cardiorenal outcomes in CKD. We studied the individual and combined effects of the vitamin D receptor activator paricalcitol (PARI) and dietary sodium restriction on residual albuminuria in CKD. In a multicenter, randomized, placebo (PLAC)-controlled, crossover trial, 45 patients with nondiabetic CKD stages 1-3 and albuminuria >300 mg/24 h despite ramipril at 10 mg/d and BP<140/90 mmHg were treated for four 8-week periods with PARI (2 μg/d) or PLAC, each combined with a low-sodium (LS) or regular sodium (RS) diet. We analyzed the treatment effect by linear mixed effect models for repeated measurements. In the intention-to-treat analysis, albuminuria (geometric mean) was 1060 (95% confidence interval, 778 to 1443) mg/24 h during RS + PLAC and 990 (95% confidence interval, 755 to 1299) mg/24 h during RS + PARI (P=0.20 versus RS + PLAC). LS + PLAC reduced albuminuria to 717 (95% confidence interval, 512 to 1005) mg/24 h (P<0.001 versus RS + PLAC), and LS + PARI reduced albuminuria to 683 (95% confidence interval, 502 to 929) mg/24 h (P<0.001 versus RS + PLAC). The reduction by PARI beyond the effect of LS was nonsignificant (P=0.60). In the per-protocol analysis restricted to participants with ≥95% compliance with study medication, PARI did provide further albuminuria reduction (P=0.04 LS + PARI versus LS + PLAC). Dietary adherence was good as reflected by urinary excretion of 174±64 mmol Na⁺ per day in the combined RS groups and 108±61 mmol Na⁺ per day in the LS groups (P<0.001). In conclusion, moderate dietary sodium restriction substantially reduced residual albuminuria during fixed dose angiotensin-converting enzyme inhibition. The additional effect of PARI was small and nonsignificant.

Why, when and how should immunosuppressive therapy considered in patients with immunoglobulin A nephropathy?

IgA nephropathy (IgAN) is the most common primary glomerulonephritis worldwide. Lifelong mesangial deposition of IgA1 complexes subsist inflammation and nephron loss, but the complex pathogenesis in detail remains unclear. In regard to the heterogeneous course, classical immunosuppressive and specific therapeutic regimens adapted to the loss of renal function will here be discussed in addition to the essential common renal supportive therapy. Renal supportive therapy alleviates secondary, surrogate effects or sequelae on renal function and proteinuria of high intraglomerular pressure and subsequent nephrosclerosis by inhibition of the renin angiotensin system (RAASB). In patients with physiological (ΔGFR < 1·5 ml/min/year) or mild (ΔGFR 1·5-5 ml/min/year) decrease of renal function and proteinuric forms (> 1 g/day after RAASB), corticosteroids have shown a reduction of proteinuria and might protect further loss of renal function. In patients with progressive loss of renal function (ΔGFR > 3 ml/min within 3 months) or a rapidly progressive course with or without crescents in renal biopsy, cyclophosphamide with high-dose corticosteroids as induction therapy and azathioprine maintenance has proved effective in one randomized controlled study of a homogeneous cohort in loss of renal function (ΔGFR). Mycophenolic acid provided further maintenance in non-randomized trials. Differentiated, precise, larger, randomized, placebo-controlled studies focused on the loss of renal function in the heterogeneous forms of IgAN are still lacking. Prospectively, fewer toxic agents will be necessary in the treatment of IgAN.

Long-term Effect of Losartan on Kidney Disease in American Indians With Type 2 Diabetes: A Follow-up Analysis of a Randomized Clinical Trial

OBJECTIVE

To determine whether early administration of losartan slows progression of diabetic kidney disease over an extended period.

RESEARCH DESIGN AND METHODS

We conducted a 6-year clinical trial in 169 American Indians with type 2 diabetes and urine albumin/creatinine ratio <300 mg/g; 84 participants were randomly assigned to receive losartan and 85 to placebo. Primary outcome was a decline in glomerular filtration rate (GFR; iothalamate) to ≤60 mL/min or to half the baseline value in persons who entered with GFR <120 mL/min. At enrollment, GFR averaged 165 mL/min (interquartile range 49-313 mL/min). During the trial, nine persons reached the primary outcome with a hazard ratio (HR; losartan vs. placebo) of 0.50 (95% CI 0.12-1.99). Participants were then followed posttrial for up to 12 years, with treatment managed outside the study. The effect of losartan on the primary GFR outcome was then reanalyzed for the entire study period, including the clinical trial and posttrial follow-up.

RESULTS

After completion of the clinical trial, treatment with renin-angiotensin system inhibitors was equivalent in both groups. During a median of 13.5 years following randomization, 29 participants originally assigned to losartan and 35 to placebo reached the primary GFR outcome with an HR of 0.72 (95% CI 0.44-1.18).

CONCLUSIONS

Long-term risk of GFR decline was not significantly different between persons randomized to early treatment with losartan and those randomized to placebo. Accordingly, we found no evidence of an extended benefit of early losartan treatment on slowing GFR decline in persons with type 2 diabetes.

Effects of blood pressure lowering on outcome incidence in hypertension: 7. Effects of more vs. less intensive blood pressure lowering and different achieved blood pressure levels - updated overview and meta-analyses of randomized trials

BACKGROUND AND OBJECTIVES

Previous meta-analyses of our group have investigated the cardiovascular effects of more vs. less intense blood pressure (BP) treatment and the BP levels to be achieved by treatment. A few additional trials have been completed recently, particularly the large SPRINT study. Updating of the previous meta-analyses has been done with the objective of further clarifying the practical question of BP targets of antihypertensive treatment.

METHODS

Among randomized-controlled trials (RCTs) of BP lowering treatment between 1966 and 2015, 16 (52 235 patients) compared more vs. less intense treatment and fulfilled other preset criteria, and in 34 (138 127 patients) SBP in the active (vs. placebo) or the more (vs. less) intense treatment was below (vs., respectively, above) three predetermined cutoffs. For their meta-analyses risk ratios (RR) and 95% confidence intervals, standardized to -10/-5 mmHg SBP/DBP reduction, and absolute risk reductions of seven fatal and nonfatal outcomes were calculated.

RESULTS

More intense BP lowering significantly reduced risk of stroke [RR 0.71 (0.60-0.84)], coronary events [0.80 (0.68-0.95)], major cardiovascular events [0.75 (0.68-0.85)] and cardiovascular mortality [0.79 (0.63-0.97)], but not heart failure and all-cause death. When the 16 RCTs were stratified according to cardiovascular death risk, relative risk reduction did not differ between strata, but absolute risk reduction increased with cardiovascular risk, though the residual risk also increased. Stratification of the 34 RCTs according to the three different SBP cutoffs (150, 140 and 130 mmHg) showed that a SBP/DBP difference of -10/-5 mmHg across each cutoff significantly reduced risk of all outcomes to the same proportion (relative risk reduction), but absolute risk reduction of most outcomes had a significant trend to decrease at lower cutoffs.

CONCLUSION

Updating of previous meta-analyses indicates that more vs. less intense BP lowering can reduce not only stroke and coronary events, but also cardiovascular mortality. Including data from recent RCTs also shows that all major outcomes can be reduced by lowering SBP a few mmHg below vs. above 130 mmHg, but absolute risk reduction becomes smaller, suggesting patients at lower initial SBP were at a lower level of cardiovascular risk.

Antihypertensive treatments in adult autosomal dominant polycystic kidney disease: network meta-analysis of the randomized controlled trials

Background

Blood pressure (BP) control is one of the most important treatments of Autosomal dominant polycystic kidney disease (ADPKD). The comparative efficacy of antihypertensive treatments in ADPKD patients is inconclusive.

Methods

Network meta-analysis was used to evaluate randomized controlled trials (RCT) which investigated antihypertensive treatments in ADPKD. PubMed, Embase, Ovid, and Cochrane Collaboration were searched. The primary outcome was estimated glomerular filtration rate (eGFR). Secondary outcomes were serum creatinine (Scr), urinary albumin excretion (UAE), systolic BP (SBP), diastolic BP (DBP), mean artery pressure (MAP) and left ventricular mass index (LVMI).

Results

We included 10 RCTs with 1386 patients and six interventions: angiotensin-converting enzyme inhibitors (ACEI), Angiotensin II receptor blocker (ARB), combination of ACEI and ARB, calcium channel blockers (CCB), β-blockers and dilazep. There was no difference of eGFR in all the treatments in both network and direct comparisons. No significant differences of Scr, SBP, DBP, MAP, and LVMI were found in network comparisons. However, ACEI significantly reduced SBP, DBP, MAP and LVMI when compared to CCB. Significantly increased UAE was observed in CCB compared with ACEI or ARB. Bayesian probability analysis found ARB ranked first in the surrogate measures of eGFR, UAE and SBP.

Conclusions

There is little evidence to detect differences of antihypertensive treatments on kidney disease progression in ADPKD patients. More RCTs will be needed in the future. Use of ARB may be an optimal choice in clinical practice.

Safe use of NSAIDs and RAS-inhibitors at Agogo Presbyterian Hospital, Ghana

BACKGROUND

Preventable adverse events of medication are an important cause of hospital admissions in the developed world, in which non-steroidal anti-inflammatory drugs (NSAIDs) and renin-angiotensin system (RAS-) inhibitors are frequently involved. NSAIDs and RAS-inhibitors are also often used in Ghana. The purpose of this study is to assess whether biochemical monitoring in patients on RAS-inhibitors, and co-administration of gastro protective agents (GPAs) in patients on NSAIDs, is done properly in Ghana.

MATERIAL AND METHODS

Two retrospective cross-sectional studies were carried out at the Agogo Presbyterian Hospital, Ghana, in 2013. In 114 out-and inpatients who are on NSAIDs, the risk for gastrointestinal side effects and the frequency of co-administration of GPAs were determined. In 301 outpatients who are on RAS-inhibitors, the risk for renal dysfunction and the frequency of biochemical monitoring were determined. Fisher's exact test was used to determine the statistical strength.

RESULTS

Co-administration of GPAs was done in 1.8% of patients on NSAIDs. Serum creatinine and potassium monitoring within one month after initiation of treatment with RAS-inhibitors were performed in 6.3% and 3.7%, respectively. Risk factors were neither associated with prescription of a GPA in patients on NSAIDs (p=0.134), nor in performing biochemical monitoring in patients on RAS-inhibitors (p=0.219 for creatinine, p=0.062 for potassium).

CONCLUSIONS

Biochemical monitoring in patients on RAS-inhibitors and use of GPAs in patients on NSAIDs is poorly performed at the Agogo Presbyterian Hospital in Ghana. Improving the already existing Ghanaian guidelines, especially those for RAS-inhibitors, and encouraging their widespread use among prescribers should be pursued.

Social Determinants of Racial Disparities in CKD

Significant disparities in CKD rates and outcomes exist between black and white Americans. Health disparities are defined as health differences that adversely affect disadvantaged populations, on the basis of one or more health outcomes. CKD is the complex result of genetic and environmental factors, reflecting the balance of nature and nurture. Social determinants of health have an important role as environmental components, especially for black populations, who are disproportionately disadvantaged. Understanding the social determinants of health and appreciating the underlying differences associated with meaningful clinical outcomes may help nephrologists treat all their patients with CKD in an optimal manner. Altering the social determinants of health, although difficult, may embody important policy and research efforts, with the ultimate goal of improving outcomes for patients with kidney diseases, and minimizing the disparities between groups.

ACE-inhibitors versus angiotensin receptor blockers for prevention of events in cardiovascular patients without heart failure - A network meta-analysis

BACKGROUND

Angiotensin receptor blockers (ARBs) are a valuable option to reduce cardiovascular (CV) mortality and morbidity in cardiac patients in whom ACE-inhibitors (ACE-Is) cannot be used. However, clinical outcome data from direct comparisons between ACE-Is and ARBs are scarce, and some data have recently suggested superiority of ACE-Is over ARBs.

METHODS

We performed a Bayesian network-meta-analysis, with data from both direct and indirect comparisons, from 27 randomized controlled trials (RCTs), including a total population of 125,330 patients, to assess the effects of ACE-Is and ARBs on the composite endpoint of CV death, myocardial infarction (MI) and stroke, and on all-cause death, new-onset heart failure (HF) and new-onset diabetes mellitus (DM) in high CV risk patients without HF.

RESULTS

Using placebo as a common comparator, we found no significant differences between ACE-Is and ARBs in preventing the composite endpoint of CV death, MI and stroke (RR: 0.92; 95% CI 0.78-1.08). When components of the composite outcome were analysed separately, ACEi and ARBs were associated with a similar risk of CV death (RR: 0.92; 95% CI 0.73-1.10), MI (RR: 0.91; 95% CI 0.78-1.07) and stroke (RR: 0.97; 95% CI 0.79-1.19), as well as a similar incident risk of all-cause death (RR: 0.94; 95% CI 0.85-1.05), new-onset HF (RR: 0.92; 95% CI 0.77-1.15) and new-onset DM (RR: 99; 95% CI 0.81-1.21).

CONCLUSIONS

With the limitations of indirect comparisons, we found that in patients at high CV risk without HF, ARBs were similar to ACE-Is in preventing the composite endpoint of CV death, MI and stroke. Compared with ARBs, we found no evidence of statistical superiority for ACE-Is, as a class, in preventing incident risk of all-cause death, CV death, MI, stroke, new-onset DM and new-onset HF.

Optimal care of lupus nephritis patients

Optimal care of lupus nephritis patients should include the treatment of proteinuria and hypertension, other measures to delay the progression of chronic kidney disease, the vigorous management of cardiovascular risk factors and finally, the treatment of advanced chronic kidney disease and its consequences. These topics are briefly reviewed in the present paper, with particular emphasis on the recent progresses in antiproteinuric treatment.

Angiotensin inhibition or blockade for the treatment of patients with quiescent lupus nephritis and persistent proteinuria

Angiotensin-converting enzyme inhibitor (ACEI) or angiotensin II receptor blocker (ARB) reduces proteinuria and the rate of renal function deterioration in diabetic nephropathy and other glomerular diseases, but its role in quiescent lupus nephritis has not been established. We conducted a retrospective study to investigate the effects of ACEI/ARB on proteinuria and renal function in patients with persistent proteinuria (>1 g/day) despite resolution of acute lupus nephritis following immunosuppressive treatment. Fourteen out of 92 patients were included. The duration of treatment with ACEI/ARB was 52.1 ± 35.7 months. The levels of proteinuria, serum albumin, serum creatinine, systolic and diastolic blood pressure were 1.10 to 6.90 g/day, 35.8 ± 3.6 g/L, 102.54 ± 34.48 μmol/L, 137.6 ± 10.9 and 81.9 ± 9.2 mmHg at baseline. Proteinuria and serum albumin showed significant sustained improvements after 6 and 24 months of treatment. Comparison of slopes for serial proteinuria, albumin and reciprocal of serum creatinine before and after treatment showed significant improvements in six (43%), eight (57%) and two patients, respectively. At last follow-up proteinuria remained significantly lower (0.36 g/day, P = 0.043) and albumin higher (41.3 ± 2.2 g/L, P = 0.023). Eleven (78.6%) patients had proteinuria improved by >50%, and five had insignificant proteinuria at last follow-up. Systolic blood pressure was significantly reduced from 6 months onwards, but this did not correlate with proteinuria reduction. Diastolic blood pressure, serum creatinine, creatinine clearance, anti-dsDNA, C3 and haemoglobin were not altered. We conclude that ACEI/ARB effectively reduces proteinuria and improves serum albumin in patients with persistent proteinuria despite quiescent lupus nephritis.

Should We STOP Angiotensin Converting Enzyme Inhibitors/Angiotensin Receptor Blockers in Advanced Kidney Disease?

Chronic kidney disease (CKD) is a worldwide public health problem associated with a high prevalence of cardiovascular disease (CVD) and impaired quality of life. Previous research for preventing loss of glomerular filtration rate (GFR) has focused on reducing blood pressure (BP) and proteinuria. Angiotensin converting enzyme inhibitors (ACEi) and angiotensin II receptor antagonists (ARB) are commonly used in patients with early CKD, but their value in advanced CKD (estimated GFR (eGFR) ≤30 ml/min/1.73 m2) is unknown. There remains a debate about the omission of ACEi/ARB in patients with advanced CKD and their use in association with CVD or heart failure. Does the potential gain in eGFR with ACEi/ARB cessation outweigh the potential adverse cardiovascular outcomes? This paper reviews the current literature that addresses this issue. Several controversies are discussed. Although lowering BP reduces cardiovascular events, evidence suggests that ACEi/ARBs are not superior to other antihypertensive agents. There are no studies assessing the benefits of ACEi/ARB therapy in cardiovascular risk reduction in advanced non-dialysis CKD. The STOP ACEi trial will strengthen the evidence base and shed light on the potential merits and dangers of ACEi/ARB use in advanced CKD on renal function and cardiovascular outcomes.

Effect of benazepril, robenacoxib and their combination on glomerular filtration rate in cats

Background

Combined use of angiotensin-converting enzyme inhibitors and nonsteroidal anti-inflammatory drugs may induce acute kidney injury in humans, especially when combined with diuretics. The objective of this investigation was to evaluate the effects of benazepril, robenacoxib and their combination in healthy cats.

In each of two studies (study 1 followed by study 2), 32 healthy cats were randomised to one of four groups (n = 4 male and 4 female cats per group) in a parallel-group design. The groups received orally once daily for 7 days either placebo (control group), benazepril, robenacoxib or benazepril plus robenacoxib. In study 2, all groups received in addition 0.5 mg/kg furosemide twice daily by subcutaneous injection for 7 days.

Results

Benazepril, robenacoxib and their combination were well tolerated as evidenced from lack of clinical signs and no negative effects on body weight, feed consumption and clinical chemistry, haematology and urinalysis variables.

The primary endpoint of the study was the glomerular filtration rate (GFR), which was estimated from the plasma clearance of iohexol. In the absence of furosemide, GFR was significantly higher in cats receiving the combination of benazepril plus robenacoxib compared to the other three groups, and was also significantly higher in females receiving only benazepril compared to the control.

Administration of furosemide induced diuresis, reduced GFR and activated the renin-aldosterone-angiotensin system, evidenced from increased plasma renin activity and plasma aldosterone concentrations. Compared to the control group in cats treated with furosemide, GFR was increased by benazepril (females only) but decreased by robenacoxib (males only). Benazepril, robenacoxib and their combination significantly inhibited the increase in plasma aldosterone induced by furosemide.

Conclusions

The combination of benazepril and robenacoxib was well tolerated and either increased or had a neutral effect on GFR in healthy cats without or with concomitant furosemide. The combination of benazepril and robenacoxib reduced plasma aldosterone concentrations increased by furosemide. It is recommended to test the efficacy and safety of the combined use of benazepril and robenacoxib in cats with clinical disease, notably proteinuric chronic kidney disease.

Relationship of proximal tubular injury to chronic kidney disease as assessed by urinary kidney injury molecule-1 in five cohort studies

BACKGROUND

The primary biomarkers used to define CKD are serum creatinine and albuminuria. These biomarkers have directed focus on the filtration and barrier functions of the kidney glomerulus even though albuminuria results from tubule dysfunction as well. Given that proximal tubules make up ∼90% of kidney cortical mass, we evaluated whether a sensitive and specific marker of proximal tubule injury, urinary kidney injury molecule-1 (KIM-1), is elevated in individuals with CKD or with risk factors for CKD.

METHODS

We measured urinary KIM-1 in participants of five cohort studies from the USA and Sweden. Participants had a wide range of kidney function and were racially and ethnically diverse. Multivariable linear regression models were used to test the association of urinary KIM-1 with demographic, clinical and laboratory values.

RESULTS

In pooled, multivariable-adjusted analyses, log-transformed, creatinine-normalized urinary KIM-1 levels were higher in those with lower eGFR {β = -0.03 per 10 mL/min/1.73 m(2) [95% confidence interval (CI) -0.05 to -0.02]} and greater albuminuria [β = 0.16 per unit of log albumin:creatinine ratio (95% CI 0.15-0.17)]. Urinary KIM-1 levels were higher in current smokers, lower in blacks than nonblacks and lower in users versus nonusers of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers.

CONCLUSION

Proximal tubule injury appears to be an integral and measurable element of multiple stages of CKD.

The next generation of therapeutics for chronic kidney disease

Chronic kidney disease (CKD) represents a leading cause of death in the United States. There is no cure for this disease, with current treatment strategies relying on blood pressure control through blockade of the renin-angiotensin system. Such approaches only delay the development of end-stage kidney disease and can be associated with serious side effects. Recent identification of several novel mechanisms contributing to CKD development - including vascular changes, loss of podocytes and renal epithelial cells, matrix deposition, inflammation and metabolic dysregulation - has revealed new potential therapeutic approaches for CKD. This Review assesses emerging strategies and agents for CKD treatment, highlighting the associated challenges in their clinical development.

The Unappreciated Role of Extrarenal and Gut Sensors in Modulating Renal Potassium Handling: Implications for Diagnosis of Dyskalemias and Interpreting Clinical Trials

In addition to the classic and well-established "feedback control" of potassium balance, increasing investigative attention has focused on a novel and not widely recognized complementary regulatory paradigm for maintaining potassium homeostasis-the "feed-forward control" of potassium balance. This regulatory mechanism, initially defined in rumen, has recently been validated in normal human subjects. Studies are being conducted to determine the location for this putative potassium sensor and to evaluate potential signals, which might increase renal potassium excretion. Awareness of this more updated integrative control mechanism for potassium homeostasis is ever more relevant today, when the medical community is increasingly focused on the challenges of managing the hyperkalemia provoked by renin-angiotensin-aldosterone system inhibitors (RAASis). Recent studies have demonstrated a wide gap between RAASi prescribing guidelines and real-world experience and have highlighted that this gap is thought to be attributable in great part to hyperkalemia. Consequently we require a greater knowledge of the complexities of the regulatory mechanisms subserving potassium homeostasis. Sodium polystyrene sulfonate has long been the mainstay for treating hyperkalemia, but its administration is fraught with challenges related to patient discomfort and colonic necrosis. The current and imminent availability of newer potassium binders with better tolerability and more predictive dose-response potassium removal should enhance the management of hyperkalemia. Consequently it is essential to better understand the intricacies of mammalian colonic K+ handling. We discuss colonic transport of K+ and review evidence for potassium (BK) channels being responsible for increased stool K+ in patients with diseases such as ulcerative colitis.

Incidence of and risk factors for severe acute kidney injury in children with heart failure treated with renin-angiotensin system inhibitors

No large cohort study has yet determined the incidence of acute kidney injury (AKI) in children with heart failure treated with renin-angiotensin system (RAS) inhibitors. We thus retrospectively analyzed the incidence and risk factors for severe AKI (stages 2-3 according to the Kidney Disease Improving Global Outcomes (KDIGO) guidelines) at our institutions from 2008 to 2011. Among 312 children (162 boys; median age, 7.3 months), 59 cases of AKI occurred in 45 children. The incidence of AKI was 14.3 cases per 100 person-years overall (follow-up 413.6 person-years), or 27.3, 16.8, and 4.5 cases per 100 person-years in children aged <1, 1-3, and ≥4 years, respectively. Among them, 23 (39.0 %) children had metabolic acidosis and 14 (23.7 %) had hyperkalemia. Younger age, myocardial disease, cyanotic congenital heart disease, use of spironolactone, and cardiac surgery were independent risk factors for AKI. Furthermore, 37.3 % of children suffered dehydration during AKI.

CONCLUSION

AKI incidence is relatively high in children, particularly younger children, with heart failure treated using RAS inhibitors. Careful monitoring of renal function and serum electrolytes is essential. Proper management of fluid balance after infection and cardiac surgery may reduce the risk of AKI. Temporary discontinuation in RAS inhibitors should be considered during dehydration or surgery.

WHAT IS KNOWN

• Angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) are the two main classes of renin-angiotensin system (RAS) inhibitors used to treat hypertension, heart failure, and chronic kidney disease. Acute kidney injury (AKI) and hyperkalemia are potentially life-threatening complications associated with the use of ACEIs and ARBs. Some reports have suggested that dehydration and cardiac surgery are risk factors for AKI in children. However, no large-scale cohort studies have determined the incidence of AKI, its risk factors, and its outcomes in children with heart failure treated with ACEIs and/or ARBs. What is new: • In this retrospective cohort study, we determined the incidence, severity, and risk factors for severe AKI in children with heart failure treated with ACEIs and/or ARBs. The incidence of AKI in these children was relatively high (14.3 episodes per 100 person-years). In addition, younger age, myocardial disease, cyanotic congenital heart disease, concomitant use of spironolactone, and cardiac surgery were risk factors for AKI. Furthermore, 37.3 % of children had dehydration during AKI episodes. • Our results suggested that appropriate fluid balance after infection and cardiac surgery might reduce the risk of AKI and its complications. Temporary discontinuation or reductions in the levels of ACEIs and/or ARBs during dehydration or before surgery may also be warranted in these patients.

Potassium homeostasis and dyskalemias: the respective roles of renal, extrarenal, and gut sensors in potassium handling

Integrated mechanisms controlling the maintenance of potassium homeostasis are well established and are defined by the classic "feedback control" of potassium balance. Recently, increasing investigative attention has focused on novel physiological paradigms that increase the complexity and precision of homeostasis. This review briefly considers the classic and well-established feedback control of potassium and then considers subsequent investigations that inform on an intriguing and not widely recognized complementary paradigm: the "feed-forward control of potassium balance." Feed-forward control refers to a pathway in a homeostatic system that responds to a signal in the environment in a predetermined manner, without responding to how the system subsequently reacts (i.e., without responding to feedback). Studies in several animal species, and recently in humans, have confirmed the presence of a feed-forward control mechanism that is capable of mediating potassium excretion independent of changes in serum potassium concentration and aldosterone. Knowledge imparted by this update of potassium homeostasis hopefully will facilitate the clinical management of hyperkalemia in patients with chronic and recurrent hyperkalemia. Awareness of this updated integrative control mechanism for potassium homeostasis is more relevant today when the medical community is increasingly focused on leveraging and expanding established renin-angiotensin-aldosterone system inhibitor treatment regimens and on successfully coping with the challenges of managing hyperkalemia provoked by renin-angiotensin-aldosterone system inhibitors. These new insights are relevant to the future design of clinical trials delineating renal potassium handling.

Ramipril versus placebo in kidney transplant patients with proteinuria: a multicentre, double-blind, randomised controlled trial

BACKGROUND

Angiotensin-converting enzyme inhibitors have been shown to reduce the risk of end-stage renal disease and death in non-transplant patients with proteinuria. We examined whether ramipril would have a similar beneficial effect on important clinical outcomes in kidney transplant recipients with proteinuria.

METHODS

In this double-blind, placebo-controlled, randomised trial, conducted at 14 centres in Canada and New Zealand, we enrolled adult renal transplant recipients at least 3-months post-transplant with an estimated glomerular filtration rate (GFR) of 20 mL/min/1·73m(2) or greater and proteinuria 0·2 g per day or greater and randomly assigned them to receive either ramipril (5 mg orally twice daily) or placebo for up to 4 years. Patients completing the final 4-year study visit were invited to participate in a trial extension phase. Treatment was assigned by centrally generated randomisation with permuted variable blocks of 2 and 4, stratified by centre and estimated GFR (above or below 40 mL/min/1·73 m(2)). The primary outcome was a composite consisting of doubling of serum creatinine, end-stage renal disease, or death in the intention-to-treat population. The principal secondary outcome was the change in measured GFR. We ascertained whether any component of the primary outcome had occurred at each study visit (1 month and 6 months post-randomisation, then every 6 months thereafter). This trial is registered with ISRCTN, number 78129473.

FINDINGS

Between Aug 23, 2006, and March 28, 2012, 213 patients were randomised. 109 were allocated to placebo and 104 were allocated to ramipril, of whom 109 patients in the placebo group and 103 patients in the ramipril group were analysed and the trial is now complete. The intention to treat population (placebo n=109, ramipril n=103) was used for the primary analysis and the trial extension phase analysis. The primary outcome occurred in 19 (17%) of 109 patients in the placebo group and 14 (14%) of 103 patients in the ramipril group (hazard ratio [HR] 0·76 [95% CI 0·38-1·51]; absolute risk difference -3·8% [95% CI -13·6 to 6·1]). With extended follow-up (mean 48 months), the primary outcome occurred in 27 patients (25%) in the placebo group and 25 (24%) patients in the ramipril group (HR 0·96 [95% CI 0·55-1·65]); absolute risk difference: -0·5% (95% CI -12·0 to 11·1). There was no significant difference in the rate of measured GFR decline between the two groups (mean difference per 6-month interval: -0·16 mL/min/1·73m(2) (SE 0·24); p=0·49). 14 (14%) of patients died in the ramipril group and 11 (10%) in the placebo group, but the difference between groups was not statistically significant (HR 1·45 [95% CI 0·66 to 3·21]). Adverse events were more common in the ramipril group (39 [38%]) than in the placebo group (24 [22%]; p=0·02).

INTERPRETATION

Treatment with ramipril compared with placebo did not lead to a significant reduction in doubling of serum creatinine, end-stage renal disease, or death in kidney transplant recipients with proteinuria. These results do not support the use of angiotensin-converting enzyme inhibitors with the goal of improving clinical outcomes in this population.

FUNDING

Canadian Institutes of Health Research.

Benazepril: Nephropathy (Non-diabetic)

This Hospital Pharmacy feature is extracted from Off-Label Drug Facts, a publication available from Wolters Kluwer Health. Off-Label Drug Facts is a practitioner-oriented resource for information about specific drug uses that are unapproved by the US Food and Drug Administration. This new guide to the literature enables the health care professional or clinician to quickly identify published studies on off-label uses and determine if a specific use is rational in a patient care scenario. References direct the reader to the full literature for more comprehensive information before patient care decisions are made. Direct questions or comments regarding Off-Label Drug Uses to jgeneral@ku.edu .

Diagnosis and treatment of early renal disease in patients with type 2 diabetes mellitus: what are the clinical needs?

Renal disease is prevalent in patients with diabetes mellitus type 2. Aggressive metabolic control and lowering of systemic and/or intraglomerular blood pressure are effective interventions but not without side effects. Thus a better, early identification of patients at risk for incidence or progression to end-stage renal failure by the use of new, validated biomarkers is highly desirable. In the majority of patients, hypertension and hyperglycaemia are pathogenetically important pathways for the progression of renal disease. Nonetheless even aggressive therapy targeting these factors does not eliminate the risk of end-stage renal failure and experimental evidence suggests that many other pathways (e.g. tubulointerstitial hypoxia or inflammation etc.) also contribute. As their individual importance might vary from patient to patient, interventions which interfere are likely not to be therapeutically effective in all subjects. In this situation, an option to preserve the statistical power of clinical trials is to rely on biomarkers that reflect individual pathophysiology. In current clinical practice, albuminuria is the biomarker that has been best evaluated to guide stratified/personalized therapy but there is a clear need to expand our diagnostic abilities.

RAAS inhibition and the course of Alport syndrome

Alport syndrome (AS) is a hereditary progressive glomerulonephritis with a high life-time risk for end-stage renal disease (ESRD). Most patients will reach ESRD before the age of 30 years, while a subset of them with milder mutations will do so at older ages, even after 50 years. Frequent extrarenal manifestations are hearing loss and ocular abnormalities. AS is a genetically heterogeneous collagen IV nephropathy, with 85% of the cases caused by mutations in the X-linked COL4A5 gene and the rest by homozygous or compound heterozygous mutations in either the COL4A3 or the COL4A4 gene on chromosome 2q36-37. There is no radical cure for the disease and attempts to use various stem cell therapies in animal models have been met with ambiguous success. However, effective treatment has been accomplished with pharmacological intervention at the renin-angiotensin-aldosterone system (RAAS), first in animal models of AS and more recently in humans. Angiotensin converting enzyme inhibitors (ACEis) and angiotensin receptor blockers (ARBs) have been shown to significantly delay the progression of chronic kidney disease and the onset of ESRD. Also, renin inhibitors and aldosterone blockade were used with positive results, while the combination of ACEis and ARBs was met with mixed success. An important study, the EARLY-PROTECT, aims at evaluating the efficacy of ACEis when administered very early on in children with AS. Novel therapies are also tested experimentally or are under design in animal models by several groups, including the use of amniotic fluid stem cells and synthetic chaperones.

Epidemiology of hyperkalemia: an update

Hyperkalemia represents one of the most important acute electrolyte abnormalities, due to its potential for causing life-threatening arrhythmias. In individuals with normal kidney function hyperkalemia occurs relatively infrequently, but it can be much more common in patients who have certain predisposing conditions. Patients with chronic kidney disease are the most severely affected group, by virtue of their decreased ability to excrete potassium and because they commonly have additional predisposing conditions that often cluster within patients with chronic kidney disease. These conditions include comorbidities (e.g., diabetes mellitus) and the use of various medications, of which the most important are renin-angiotensin-aldosterone system inhibitors (RAASis). Hyperkalemia is associated with increased risk for all-cause mortality and for malignant arrhythmias such as ventricular fibrillation. The increased risk for adverse outcomes is observed even in serum potassium ranges that are often not considered targets for therapeutic interventions. The heightened risk of mortality associated with hyperkalemia is present in all patient populations, even those in whom hyperkalemia occurs otherwise rarely, such as individuals with normal kidney function.

Podocyte directed therapy of nephrotic syndrome-can we bring the inside out?

Several of the drugs currently used for the treatment of glomerular diseases are prescribed for their immunotherapeutic or anti-inflammatory properties, based on the current understanding that glomerular diseases are mediated by immune responses. In recent years our understanding of podocytic signalling pathways and the crucial role of genetic predispositions in the pathology of glomerular diseases has broadened. Delineation of those signalling pathways supports the hypothesis that several of the medications and immunosuppressive agents used to treat glomerular diseases directly target glomerular podocytes. Several central downstream signalling pathways merge into regulatory pathways of the podocytic actin cytoskeleton and its connection to the slit diaphragm. The slit diaphragm and the cytoskeleton of the foot process represent a functional unit. A breakdown of the cytoskeletal backbone of the foot processes leads to internalization of slit diaphragm molecules, and internalization of slit diaphragm components in turn negatively affects cytoskeletal signalling pathways. Podocytes display a remarkable ability to recover from complete effacement and to re-form interdigitating foot processes and intact slit diaphragms after pharmacological intervention. This ability indicates an active inside-out signalling machinery which stabilizes integrin complex formations and triggers the recycling of slit diaphragm molecules from intracellular compartments to the cell surface. In this review we summarize current evidence from patient studies and model organisms on the direct impact of immunosuppressive and supportive drugs on podocyte signalling pathways. We highlight new therapeutic targets that may open novel opportunities to enhance and stabilize inside-out pathways in podocytes.

Multicentre randomized controlled trial of angiotensin-converting enzyme inhibitor/angiotensin receptor blocker withdrawal in advanced renal disease: the STOP-ACEi trial

BACKGROUND

Blood pressure (BP) control and reduction of urinary protein excretion using agents that block the renin-angiotensin aldosterone system are the mainstay of therapy for chronic kidney disease (CKD). Research has confirmed the benefits in mild CKD, but data on angiotensin-converting enzyme inhibitor (ACEi) or angiotensin receptor blocker (ARB) use in advanced CKD are lacking. In the STOP-ACEi trial, we aim to confirm preliminary findings which suggest that withdrawal of ACEi/ARB treatment can stabilize or even improve renal function in patients with advanced progressive CKD.

METHODS

The STOP-ACEi trial (trial registration: current controlled trials, ISRCTN62869767) is an investigator-led multicentre open-label, randomized controlled clinical trial of 410 participants with advanced (Stage 4 or 5) progressive CKD receiving ACEi, ARBs or both. Patients will be randomized in a 1:1 ratio to either discontinue ACEi, ARB or combination of both (experimental arm) or continue ACEi, ARB or combination of both (control arm). Patients will be followed up at 3 monthly intervals for 3 years. The primary outcome measure is eGFR at 3 years. Secondary outcome measures include the number of renal events, participant quality of life and physical functioning, hospitalization rates, BP and laboratory measures, including serum cystatin-C. Safety will be assessed to ensure that withdrawal of these treatments does not cause excess harm or increase mortality or cardiovascular events such as heart failure, myocardial infarction or stroke.

RESULTS

The rationale and trial design are presented here. The results of this trial will show whether discontinuation of ACEi/ARBs can improve or stabilize renal function in patients with advanced progressive CKD. It will show whether this simple intervention can improve laboratory and clinical outcomes, including progression to end-stage renal disease, without causing an increase in cardiovascular events.

Patiromer: a clinical review

IMPORTANCE

Patiromer FOS (for oral suspension), formerly known as RLY5016, is pending FDA approval for the treatment of hyperkalemia. Once approved, patiromer, as well as a second agent known as sodium zirconium cyclosilicate (ZS-9), will be among the new therapeutic options available to treat hyperkalemia in over 50 years.

OBJECTIVE

The primary objective of this review is to analyze the efficacy and safety of patiromer to treat hyperkalemia and compare its pharmacokinetics to currently available sodium polystyrene sulfonate (SPS) therapy. Patiromer was studied in patients with chronic kidney disease and/or heart failure for both acute and chronic therapy.

EVIDENCE REVIEW

Studies of patiromer were obtained via a literature search of PubMed database and Google Scholar (2000 to the present) using 'patiromer', 'RLY5016', and 'hyperkalemia management' as keywords. Additional references were identified from fda.gov, clinicaltrials.gov, and the pharmaceutical manufacturer, Relypsa Inc.

FINDINGS

Three published clinical trials, ten posters, one clinical trial commentary, three editorials and one oral presentation were obtained. The materials discussed three main clinical trials (PEARL-HF, OPAL-HK and AMETHYST-DN) and examined the safety and efficacy of patiromer in patients with hyperkalemia or at risk for hyperkalemia who have chronic kidney disease (CKD), type 2 diabetes mellitus (T2DM), hypertension and/or heart failure (HF) while receiving renin-angiotensin-aldosterone system inhibitors (RAASis). All three studies achieved their primary endpoints and reduced serum potassium. The PEARL-HF study increased the proportion of patients able to titrate their spironolactone dose from 25 mg/day to 50 mg/day in patients with normokalemia who had a history of hyperkalemia or an estimated glomerular filtration rate of <60 mL/min. The OPAL-HK study allowed patients receiving patiromer to remain on their RAASi therapy. The AMETHYST-DN study demonstrated that patiromer reduced and maintained mean serum potassium ≤5.0 mEq/L for up to 1 year, with a low rate of hypokalemia. Adverse events (AEs) were similar between studies. The most commonly reported adverse event was constipation.

CONCLUSIONS AND RELEVANCE

Patiromer is effective in decreasing serum potassium, preventing recurrence of hyperkalemia, and reducing RAASi discontinuation. Compared to current SPS therapy, patiromer may be the preferred option to treat hyperkalemia, once approved. Patiromer is well tolerated and is not associated with serious AEs.

The Association of Losartan and Ramipril Therapy With Kidney and Cardiovascular Outcomes in Patients With Chronic Kidney Disease: A Chinese Nation-Wide Cohort Study in Taiwan

The aim of this nation-wide cohort study was to assess the association of using an angiotensin-converting enzyme inhibitor (ACEi) or angiotensin II receptor blocker (ARB) therapy on the prognosis of hypertensive patients with chronic kidney disease (CKD). We used Cox's proportional hazard regression model to estimate hazard ratios (HRs) for the risk of end-stage renal disease (ESRD), all-cause mortality, cardiovascular mortality, and first hospitalization for cardiovascular disease (CVD) for losartan and ramipril versus conventional antihypertensive agents. In total, 136,266 hypertensive patients with CKD in Taiwan were followed up from 2001 to 2008. In an average follow-up of 5.9 years, 7364 (5.40%) patients reached ESRD, 4165 (3.06%) patients died, and 6163 (4.52%) patients had their first hospitalization for CVD. Use of losartan or ramipril was associated with a lower risk of the endpoints compared with the conventional group. In the losartan group, the risks of ESRD, all- and cardiovascular-cause mortality, and first hospitalization for CVD were decreased by 9.2% (P = 0.01), 24.6% (P < 0.001), 12.4% (P = 0.03), and 36.0% (P = 0.01), respectively. In the ramipril group, these risks decreased by 7.6% (P = 0.02) for ESRD, 56.9% (P < 0.001) for all-cause mortality, 7.5% (P = 0.04) for cardiovascular mortality, and 24.7% (P < 0.001) for first hospitalization. This study indicated that losartan and ramipril had distinct association on the prognosis of hypertensive patients with CKD, and was first to disclose that the mean time to reach each endpoint for patients in the losartan, ramipril, and conventional group was not significantly different. However, further study is needed to confirm results of the present study.

Long-term outcome of childhood IgA nephropathy with minimal proteinuria

BACKGROUND

Some patients with childhood immunoglobulin A nephropathy (IgAN) progress to end-stage renal disease within 20 years, while others achieve spontaneous remission even without medication. Prognosis of IgAN with minimal proteinuria (MP-IgAN, <0.5 g/day/1.73 m(2)) at diagnosis seems to be generally good. However, the long-term outcome for patients with childhood MP-IgAN has not yet been determined.

METHODS

We retrospectively analyzed 385 children newly diagnosed with biopsy-proven IgAN between June 1976 and July 2009 whose renal biopsy specimens could be evaluated by the Oxford classification criteria. Of these 385 children with IgAN, 106 (27.5%) were diagnosed with MP-IgAN. We compared clinical and pathological findings between the 106 patients with MP-IgAN and the remaining 279 patients to elucidate the characteristics of MP-IgAN in children.

RESULTS

Patients with MP-IgAN were identified through a school screening program (73.6%) or upon presentation with gross hematuria (26.4%). Patients with MP-IgAN had significantly milder pathological symptoms than those with IgAN. The most frequently used therapeutic regimes were angiotensin converting enzyme inhibitors (30.2%) and no therapy (36.8%). None of the patients with MP-IgAN reached stage III chronic kidney disease within 15 years after onset. Four patients with MP-IgAN (3.8 %) received immunosuppressive therapy during the course of the disease.

CONCLUSION

Our results indicate that the outcome of patients with a diagnosis of childhood MP-IgAN is good, but that careful long-term observation is required.

Renin-Angiotensin System Inhibitors and Kidney and Cardiovascular Outcomes in Patients With CKD: A Bayesian Network Meta-analysis of Randomized Clinical Trials

BACKGROUND

There is much uncertainty regarding the relative effects of angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) in populations with chronic kidney disease (CKD).

STUDY DESIGN

Systematic review and Bayesian network meta-analysis.

SETTING & POPULATION

Patients with CKD treated with renin-angiotensin system (RAS) inhibitors.

SELECTION CRITERIA FOR STUDIES

Randomized trials in patients with CKD treated with RAS inhibitors.

PREDICTOR

ACE inhibitors and ARBs compared to each other and to placebo and active controls.

OUTCOME

Primary outcome was kidney failure; secondary outcomes were major cardiovascular events, all-cause death.

RESULTS

119 randomized controlled trials (n = 64,768) were included. ACE inhibitors and ARBs reduced the odds of kidney failure by 39% and 30% (ORs of 0.61 [95% credible interval, 0.47-0.79] and 0.70 [95% credible interval, 0.52-0.89]), respectively, compared to placebo, and by 35% and 25% (ORs of 0.65 [95% credible interval, 0.51-0.80] and 0.75 [95% credible interval, 0.54-0.97]), respectively, compared with other active controls, whereas other active controls did not show evidence of a significant effect on kidney failure. Both ACE inhibitors and ARBs produced odds reductions for major cardiovascular events (ORs of 0.82 [95% credible interval, 0.71-0.92] and 0.76 [95% credible interval, 0.62-0.89], respectively) versus placebo. Comparisons did not show significant effects on risk for cardiovascular death. ACE inhibitors but not ARBs significantly reduced the odds of all-cause death versus active controls (OR, 0.72; 95% credible interval, 0.53-0.92). Compared with ARBs, ACE inhibitors were consistently associated with higher probabilities of reducing kidney failure, cardiovascular death, or all-cause death.

LIMITATIONS

Trials with RAS inhibitor therapy were included; trials with direct comparisons of other active controls with placebo were not included.

CONCLUSIONS

Use of ACE inhibitors or ARBs in people with CKD reduces the risk for kidney failure and cardiovascular events. ACE inhibitors also reduced the risk for all-cause mortality and were possibly superior to ARBs for kidney failure, cardiovascular death, and all-cause mortality in patients with CKD, suggesting that they could be the first choice for treatment in this population.

Circadian CLOCK Mediates Activation of Transforming Growth Factor-β Signaling and Renal Fibrosis through Cyclooxygenase 2

The circadian rhythm regulates blood pressure and maintains fluid and electrolyte homeostasis with central and peripheral clock. However, the role of circadian rhythm in the pathogenesis of tubulointerstitial fibrosis remains unclear. Here, we found that the amplitudes of circadian rhythm oscillation in kidneys significantly increased after unilateral ureteral obstruction. In mice that are deficient in the circadian gene Clock, renal fibrosis and renal parenchymal damage were significantly worse after ureteral obstruction. CLOCK-deficient mice showed increased synthesis of collagen, increased oxidative stress, and greater transforming growth factor-β (TGF-β) expression. TGF-β mRNA expression oscillated with the circadian rhythms under the control of CLOCK-BMAL1 heterodimers. The expression of cyclooxygenase 2 was significantly higher in kidneys from CLOCK-deficient mice with ureteral obstruction. Treatment with a cyclooxygenase 2 inhibitor celecoxib significantly improved renal fibrosis in CLOCK-deficient mice. Taken together, these data establish the importance of the circadian rhythm in tubulointerstitial fibrosis and suggest CLOCK/TGF-β signaling as a novel therapeutic target of cyclooxygenase inhibition.

The association of chronic kidney disease with the use of renin-angiotensin system inhibitors after acute myocardial infarction

BACKGROUND

Renin-angiotensin system (RAS) inhibitor use after acute myocardial infarction (AMI) is a quality indicator, but there may also be reasons not to use this therapy. We sought to determine how chronic kidney disease (CKD) and acute kidney injury (AKI) affected RAS inhibitor prescription after AMI in patients with and without decreased ejection fraction (EF).

METHODS

Participants from the TRIUMPH registry were categorized by admission estimated glomerular filtration rate (eGFR in mL/min per 1.73 m(2); severe [<30], moderate [30-59], mild [60-89], and no [≥90] CKD) and occurrence of AKI (an increase in creatinine ≥0.3 mg/dL or ≥50%). Renin-angiotensin system inhibitor prescriptions at discharge were compared across categories of CKD, AKI, and decreased EF (<40% vs ≥40%) using a hierarchical modified Poisson model.

RESULTS

Among 4,223 AMI patients (mean age 59.0 years, 67.0% male, 67.3% white), RAS inhibitor use decreased significantly with lower eGFR (P < .001), but there was no effect of decreased EF on this relationship (interaction P = .40). Without AKI, severe and moderate CKD were associated with significantly less RAS inhibitor use: relative risks (RRs) 0.67 (95% CIs, 0.58-0.78) and 0.94 (0.90-0.99), respectively. When AKI occurred, CKD was associated with less RAS inhibitor use: RRs 0.84 (0.76-0.93) for mild CKD, 0.78 (0.68-0.88) for moderate CKD, and 0.50 (0.42-0.61) for severe CKD. Ejection fraction <40% was associated with use (RR 1.11, 1.03-1.18), independent of renal function.

CONCLUSIONS

Chronic kidney disease and AKI are associated with fewer RAS inhibitor prescriptions at discharge, but in both AKI and non-AKI patients, eGFR was more strongly associated with use than EF.

Advances in treatment of hyperkalemia in chronic kidney disease

INTRODUCTION

Hyperkalemia is a frequent electrolyte disorder associated with life-threatening cardiac arrhythmias and sudden death. Patients prone to hyperkalemia have chronic kidney disease (CKD) either alone or in conjunction with diabetes or heart failure (HF). Although agents inhibiting the renin-angiotensin-aldosterone-system (RAAS) are currently the first-line treatments toward cardio- and nephroprotection, their administration often leads to potassium elevation in such patients and results in high rates of treatment discontinuation.

AREAS COVERED

This article provides an overview of factors interfering with potassium homeostasis and discusses emerging potassium-lowering therapies for long-term management of hyperkalemia.

EXPERT OPINION

In recent randomized clinical studies, two new oral potassium-exchanging compounds, patiromer and sodium zirconium cyclosilicate, were shown to effectively normalize elevated serum potassium and chronically maintain potassium homeostasis in hyperkalemic patients treated with RAAS blockers. Both agents exhibit good tolerability and were not associated with serious adverse effects. Although additional research is required, these drugs are promising for lowering the risk of incident hyperkalemia associated with RAAS blockade use in people with diabetes or HF who have CKD. They also provide the opportunity to test whether patients who could not previously receive RAAS blockade may benefit from their cardio- and renoprotective effects.

Cardiovascular-renal axis disorders in the domestic dog and cat: a veterinary consensus statement

OBJECTIVES

There is a growing understanding of the complexity of interplay between renal and cardiovascular systems in both health and disease. The medical profession has adopted the term "cardiorenal syndrome" (CRS) to describe the pathophysiological relationship between the kidney and heart in disease. CRS has yet to be formally defined and described by the veterinary profession and its existence and importance in dogs and cats warrant investigation. The CRS Consensus Group, comprising nine veterinary cardiologists and seven nephrologists from Europe and North America, sought to achieve consensus around the definition, pathophysiology, diagnosis and management of dogs and cats with "cardiovascular-renal disorders" (CvRD). To this end, the Delphi formal methodology for defining/building consensus and defining guidelines was utilised.

METHODS

Following a literature review, 13 candidate statements regarding CvRD in dogs and cats were tested for consensus, using a modified Delphi method. As a new area of interest, well-designed studies, specific to CRS/CvRD, are lacking, particularly in dogs and cats. Hence, while scientific justification of all the recommendations was sought and used when available, recommendations were largely reliant on theory, expert opinion, small clinical studies and extrapolation from data derived from other species.

RESULTS

Of the 13 statements, 11 achieved consensus and 2 did not. The modified Delphi approach worked well to achieve consensus in an objective manner and to develop initial guidelines for CvRD.

DISCUSSION

The resultant manuscript describes consensus statements for the definition, classification, diagnosis and management strategies for veterinary patients with CvRD, with an emphasis on the pathological interplay between the two organ systems. By formulating consensus statements regarding CvRD in veterinary medicine, the authors hope to stimulate interest in and advancement of the understanding and management of CvRD in dogs and cats. The use of a formalised method for consensus and guideline development should be considered for other topics in veterinary medicine.

Interventions for preventing the progression of autosomal dominant polycystic kidney disease

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited disorder causing kidney disease. Current clinical management of ADPKD focuses primarily on symptom control and reducing associated complications, particularly hypertension. In recent years, improved understanding of molecular and cellular mechanisms involved in kidney cyst growth and disease progression has resulted in new pharmaceutical agents to target disease pathogenesis to prevent progressive disease.

OBJECTIVES

We aimed to evaluate the effects of interventions for preventing ADPKD progression on kidney function, kidney endpoints, kidney structure, patient-centred endpoints (such as cardiovascular events, sudden death, all-cause mortality, hospitalisations, BP control, quality of life, and kidney pain), as well as the general and specific adverse effects related to their use.

SEARCH METHODS

We searched the Cochrane Renal Group's Specialised Register to 6 June 2015 using relevant search terms.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing any interventions for preventing the progression of ADPKD with other interventions or placebo were considered for inclusion without language restriction.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study risks of bias and extracted data. We summarised treatment effects on clinical outcomes, kidney function and structure and adverse events using random effects meta-analysis. We assessed heterogeneity in estimated treatment effects using the Cochran Q test and I(2) statistic. Summary treatment estimates were calculated as a mean difference (MD) or standardised mean difference (SMD) for continuous outcomes and a risk ratio (RR) for dichotomous outcomes together with their 95% confidence intervals.

MAIN RESULTS

We included 30 studies (2039 participants) that investigated 11 pharmacological interventions (angiotensin-converting enzyme inhibitors (ACEi), angiotensin receptor blockers (ARBs), calcium channel blockers, beta blockers, vasopressin receptor 2 (V2R) antagonists, mammalian target of rapamycin (mTOR) inhibitors, somatostatin analogues, antiplatelet agents, eicosapentaenoic acids, statins and vitamin D compounds) in this review.ACEi significantly reduced diastolic blood pressure (9 studies, 278 participants: MD -4.96 mm Hg, 95% CI -8.88 to -1.04), but had uncertain effects on kidney volumes (MD -42.50 mL, 95% CI -115.68 to 30.67), GFR (MD -3.41 mL/min/1.73 m(2), 95% CI -15.83 to 9.01), and SCr (MD -0.02 mg/dL, 95% CI -0.14 to 0.09), in data largely restricted to children. ACEi did not show different effects on GFR (MD -8.19 mL/min/1.73 m(2), 95% CI -29.46 to 13.07) and albuminuria (SMD -0.19, 95% CI -1.77 to 1.39) when compared with beta-blockers, or SCr (MD 0.00 mg/dL, 95% CI -0.09 to 0.10) when compared with ARBs.Data for effects of V2R antagonists on kidney function and volumes compared to placebo were limited to narrative information within a single study while these agents increased thirst (1444 participants: RR 2.70, 95% CI 2.24 to 3.24) and dry mouth (1455 participants: RR 1.33, 95% CI 1.01 to 1.76).Compared with no treatment, mTOR inhibitors had uncertain effects on kidney function (2 studies, 115 participants: MD 4.45 mL/min/1.73 m(2), 95% CI -3.20 to 12.11) and kidney volume (MD -0.08 L, 95% CI -0.75 to 0.59) but in three studies (560 participants) caused angioedema (RR 13.39, 95% CI 2.56 to 70.00), oral ulceration (RR 6.77, 95% CI 4.42 to 10.38), infections (RR 1.14, 95% CI 1.04 to 1.25) and diarrhoea (RR 1.70, 95% CI 1.26 to 2.29).Somatostatin analogues (6 studies, 138 participants) slightly improved SCr (MD -0.43 mg/dL, 95% CI -0.86 to -0.01) and total kidney volume (MD -0.62 L, 95% CI -1.22 to -0.01) but had no definite effects on GFR (MD 9.50 mL/min, 95% CI -4.45 to 23.44) and caused diarrhoea (RR 3.72, 95% CI 1.43 to 9.68).Data for calcium channel blockers, eicosapentaenoic acids, statins, vitamin D compounds and antiplatelet agents were sparse and inconclusive.Random sequence generation was adequate in eight studies, and in almost half of the studies, blinding was not present or not specified. Most studies did not adequately report outcomes, which adversely affected our ability to assess this bias. The overall drop-out rate was over 10% in nine studies, and few were conducted using intention-to-treat analyses.

AUTHORS' CONCLUSIONS

Although several interventions are available for patients with ADPKD, at present there is little or no evidence that treatment improves patient outcomes in this population and is associated with frequent adverse effects. Additional large randomised studies focused on patient-centred outcomes are needed.

Glomerular filtration rate decline as a surrogate end point in kidney disease progression trials

Chronic kidney disease (CKD) is strongly associated with increased risks of progression to end-stage kidney disease (ESKD) and mortality. Clinical trials evaluating CKD progression commonly use a composite end point of death, ESKD or serum creatinine doubling. However, due to low event rates, such trials require large sample sizes and long-term follow-up for adequate statistical power. As a result, very few interventions targeting CKD progression have been tested in randomized controlled trials. To overcome this problem, the National Kidney Foundation and Food and Drug Administration conducted a series of analyses to determine whether an end point of 30 or 40% decline in estimated glomerular filtration rate (eGFR) over 2-3 years can substitute for serum creatinine doubling in the composite end point. These analyses demonstrated that these alternate kidney end points were significantly associated with subsequent risks of ESKD and death. However, the association between, and consistency of treatment effects on eGFR decline and clinical end points were influenced by baseline eGFR, follow-up duration and acute hemodynamic effects. The investigators concluded that a 40% eGFR decline is broadly acceptable as a kidney end point across a wide baseline eGFR range and that a 30% eGFR decline may be acceptable in some situations. Although these alternate kidney end points could potentially allow investigators to conduct shorter duration clinical trials with smaller sample sizes thereby generating evidence to guide clinical decision-making in a timely manner, it is uncertain whether these end points will improve trial efficiency and feasibility. This review critically appraises the evidence, strengths and limitations pertaining to eGFR end points.