Urinary protein excretion rate is the best independent predictor of ESRF in non-diabetic proteinuric chronic nephropathies. "Gruppo Italiano di Studi Epidemiologici in Nefrologia" (GISEN)

Protein and albumin-to-creatinine ratios in random urines accurately predict 24 h protein and albumin loss in patients with kidney disease

BACKGROUND

Random urine protein-to-creatinine (PCR) and albumin-to-creatinine (ACR) ratios have been proposed as alternatives to 24 h urine measurements to simplify sample collection and overcome errors. The aim of this study was to examine the ability of PCR and ACR to predict urinary 24 h protein and albumin loss, respectively, in patients with kidney disease, and determine the most appropriate time of collection.

METHODS

Eighty-three patients were recruited from a renal outpatient clinic. In a 24 h period, each collected an early-morning urine (EMU), second and third voids, and the remaining urine passed that day. PCR and ACR were determined in random urines and compared with the 24 h loss of protein and albumin, respectively.

RESULTS

For all patients, median (range) 24 h urine protein and albumin losses were 220 (30-15600) and 60 (<8-10,557) mg, respectively. Ratios derived from each of three random urines correlated well with 24 h protein or albumin loss (Spearman's r(s) > 0.87, P < 0.0001). Receiver operator characteristic (ROC) curve analysis showed PCR accurately predicted both an abnormal 24 h urine protein > or =150 mg/24 h (areas under curves [AUC] 0.90-0.92) and significant proteinuria above 300 mg/24 h (AUC between 0.97 and 1.00). ACR accurately predicted both an abnormal 24 h urine albumin > or =30 mg/24 h (AUC 0.98 to 0.99) and frank albuminuria at > or =300 mg/24 h or > or =700 mg/24 h (AUC between 0.99 and 1.00). EMU and random urines performed equally well in predicting proteinuria and albuminuria from PCR and ACR, respectively.

CONCLUSIONS

By careful choice of cut-offs, both PCR and ACR can be used in patients with kidney disease to rule in or rule out abnormal 24 h losses of protein and albumin. EMU and, importantly, random samples can be used as surrogates for 24 h urine collections.

Influence of T-calcium channel blocker treatment on deterioration of renal function in chronic kidney disease

Some calcium channel blockers (CCBs) have renoprotective effects. Our aim was to compare the effects of different subclasses of CCBs on the deterioration of renal function in chronic kidney disease (CKD). This is a prospective, observational cohort study in a single center. The subjects were 107 nondiabetic CKD patients. The rate of deterioration of estimated glomerular filtration rate (DeltaeGFR) was calculated by [last visit eGFR - baseline eGFR/follow-up duration]. Multivariate analysis was performed using the change in urinary protein (DeltaUP) and DeltaeGFR during follow-up as response variables. CCB subclasses were L-type in 76 patients, T- and L-type in 28 patients, and nondihydropyridines in 6 patients. Multiregression analysis indicated that higher baseline proteinuria (UP) and the use of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers were associated with the decrease of UP, while the use of L-type CCBs, prednisolone, and probucol was associated with the increase of UP. The use of T- and L-type CCBs, ACEIs and diuretics was associated with a good outcome in terms of DeltaeGFR, whereas chronic glomerulonephritis, polycystic kidney disease, and higher baseline eGFR and UP were associated with a poor outcome. It is suggested that the use of T- and L-type CCB among other subclasses may improve the outcome of patients with nondiabetic CKD in terms of renal function.

Post-menopausal hormone use and albuminuria

BACKGROUND

Higher levels of urinary albumin excretion predict future hypertension and chronic kidney disease. Post-menopausal hormone use may influence the renin-angiotensin system and renal endothelial function, impacting albumin excretion. The association between post-menopausal hormone use and albuminuria is not well defined.

METHODS

We explored the cross-sectional association between duration of PMH use and albuminuria in 2445 post-menopausal, non-diabetic women from the Nurses' Health Study. Women were categorized as hormone non-users, past users or current users grouped by 3-year intervals of duration of use, from < or =3 years to >15 years. The outcome was the top decile of urine albumin/creatinine ratio (ACR). Multivariate logistic regression was used to assess the association between duration of PMH use and risk of being in the top decile.

RESULTS

The mean age was 66.8 years, and 57% were currently using PMH. The median ACR was 2.9 mg/g, and the 90th percentile was 9.2 mg/g. Compared with women with no history of PMH use, the odds ratio for being in the top ACR decile was lower for women with use of >6-9 years, >9-12 years, >12-15 years and >15 years, but there was no dose-response. The overall odds ratio was 0.55 (95% CI: 0.39-0.77) among women with >6 years of current PMH use compared with non-users. Current hormone use of shorter duration and past hormone use were not associated with albumin excretion.

CONCLUSIONS

Current PMH use of >6 years is associated with a lower urinary ACR in non-diabetic women.

How should proteinuria be detected and measured?

Proteinuria is a classic sign of kidney disease and its presence carries powerful prognostic information. Although proteinuria testing is enshrined in clinical practice guidelines, there is surprising variation among such guidelines as to the definition of clinically significant proteinuria. There is also poor agreement as to whether proteinuria should be defined in terms of albumin or total protein loss, with a different approach being used to stratify diabetic and non-diabetic nephropathy. Further, the role of reagent strip devices in the detection and assessment of proteinuria is unclear. This review explores these issues in relation to recent national and international guidelines on chronic kidney disease (CKD) and epidemiological evidence linking proteinuria and clinical outcome. The authors argue that use of urinary albumin measurement as the front-line test for proteinuria detection offers the best chance of improving the sensitivity, quality and consistency of approach to the early detection and management of CKD.

Effect of BSA-induced ER stress on SGLT protein expression levels and α-MG uptake in renal proximal tubule cells

Recent studies demonstrated that endoplasmic reticulum (ER) stress regulates glucose homeostasis and that ER stress preconditioning which induces an adaptive, protective unfolded protein response (UPR) offers cytoprotection against nephrotoxins. Thus the aim of the present study was to use renal proximal tubule cells (PTCs) to further elucidate the link between the BSA-induced ER stress and α-methyl-d-glucopyranoside (α-MG) uptake and to identify related signaling pathways. Among ER stress inducers such as high glucose, BSA, H2O2, or tumicamycin, BSA pretreatment ameliorated the reduction of Na+-glucose cotransporter (SGLT) expression and α-MG uptake by gentamicin or cyclosporine A. Immunofluorescence studies revealed that BSA (10 mg/ml) stimulated the expression of glucose-regulated protein 78 (GRP78), an ER stress biomarker. In addition, BSA increased levels of GRP78 protein expression and eukaryotic initiation factor 2α (eIF2α) phosphorylation in a time-dependent manner. Furthermore, transfection with a GRP78-specific small interfering RNA (siRNA) inhibited BSA-stimulated SGLT expression and α-MG uptake. In experiments designed to unravel the mechanisms underlying BSA-induced ER stress, BSA stimulated the production of cellular reactive oxygen species (ROS), and antioxidants such as ascorbic acid or N-acetylcysteine (NAC) blocked BSA-induced increases in GRP78 activation, eIF2α phosphorylation, SGLT expression, and α-MG uptake. Moreover, the cells upregulated peroxisome proliferator-activated receptor-γ (PPARγ) mRNA levels in response to BSA or troglitazone (a PPARγ agonist), but BSA was ineffective in the presence of GW9662 (a PPARγ antagonist). In addition, both BSA and troglitazone stimulated GRP78 and eIF2α activation, SGLT expression, and α-MG uptake, whereas GW9662 inhibited the effects of BSA. BSA also stimulated phosphorylation of JNK and NF-κB, and GW9662 or GRP78 siRNA attenuated this response. Moreover, SP600125 or SN50 effectively blocked SGLT expression and α-MG uptake in BSA- or PPARγ agonists (troglitazone or PGJ2)-treated PTCs. We conclude that BSA induces ER stress through ROS production and PPARγ activation, which subsequently activates JNK/NF-κB signaling to enhance glucose uptake in renal PTCs.

Proteinuria-induced chronic kidney disease in the ICGN/Oa mice with a mutation of Tensin2 gene

ICGN/Oa mice are used to study the pathophysiological mechanisms underlying proteinuria-induced chronic kidney disease (CKD). Recently, a mutation of tensin2 gene (Tns2) was suggested to be responsible for proteinuria in the inbred ICGN mice. We identified the wild-type (+/+), heterozygous (+/nep), and homozygous (nep/nep) ICGN/Oa mice by PCR assay. The homozygotes developed proteinuria, resulting in nephrotic syndrome (NS) as early as 5 weeks and CKD by 15 weeks. However, the heterozygotes did not show the symptoms of these renal failures. These results indicate that the homozygous tensin2 mutation is necessary for the ICGN/Oa mice to develop proteinuria-induced CKD. Furthermore, we examined the time course of tubulointerstitial fibrosis and the kinetics of tubular epithelial cells (TECs) in the ICGN/Oa mice using immunohistochemical and TUNEL assays. In the renal parenchyma of the five-week-old homozygotes, the expression of alpha-SMA and type I collagen were higher than those in the age-matched wild-type. Additionally, increased TEC proliferation was found at 5 weeks, and increased TEC apoptosis was by 15 weeks in the homozygotes. Tubulointerstitial fibrosis precedes TEC apoptosis in the proteinuria-induced CKD model mice, and that tubulointerstitial fibrosis may be the triggering event of the disease.

Supramaximal dose of candesartan in proteinuric renal disease

High levels of proteinuria predict renal deterioration, suggesting that interventions to reduce proteinuria may postpone the development of severe renal impairment. This multicenter Canadian trial evaluated whether supramaximal dosages of candesartan would reduce proteinuria to a greater extent than the maximum approved antihypertensive dosage. The authors randomly assigned 269 patients who had persistent proteinuria (> or =1 g/d) despite 7 wk of treatment with the highest approved dosage of candesartan (16 mg/d) to 16, 64, or 128 mg/d candesartan for 30 wk. The median serum creatinine level was 130.0 micromol/L (1.47 mg/dl), and the median urinary protein excretion was 2.66 g/d; most (53.9%) patients had diabetic nephropathy. The mean difference of the percentage change in proteinuria for patients receiving 128 mg/d candesartan compared with those receiving 16 mg/d candesartan was -33.05% (95% confidence interval -45.70 to -17.44; P < 0.0001). Reductions in BP were not different across the three treatment groups. Elevated serum potassium levels (K+ > 5.5 mEq/L) led to the early withdrawal of 11 patients, but there were no dosage-related increases in adverse events. In conclusion, proteinuria that persists despite treatment with the maximum recommended dosage of candesartan can be reduced by increasing the dosage of candesartan further, but serum potassium levels should be monitored during treatment.

Beyond immunosuppression – challenges in the clinical management of lupus nephritis

Lupus nephritis remains the most common severe manifestation of SLE with increased risk of death and end-stage renal disease. Although, recent research has focused on the choice of immunosuppressive in its treatment, other factors, including the quality and delivery of healthcare, the management of glucocorticoids and co-morbidity are probably of more importance. There has been significant progress in induction regimes with the successful use of mycophenolate mofetil, low dose intravenous cyclophosphamide and development of sequential regimens whereby cyclophosphamide is followed by an alternative immunosuppressive. However, the attention on the day-to-day management of lupus nephritis in the clinic has merited less attention. In this article, we aim to address more widely the major issues which are encountered regularly in the long-term management of these patients. The overall goals are the reduction of mortality and preservation of renal function.

Chronic kidney disease at high altitude

With a prevalence of 10 to 11% in the general population, it is likely that many patients with chronic kidney disease will visit or reside in mountainous areas. Little is known, however, about whether short- or long-duration, high-altitude exposure poses a risk in this patient population. Given that many areas of the kidney are marginally oxygenated even at sea level and that kidney disease may result in further renal hypoxia and hypoxia-associated renal injury, there is concern that high altitude may accelerate the progression of chronic kidney disease. In this review, we address how chronic kidney disease and its management is affected at high altitude. We postulate that arterial hypoxemia at high altitude poses a risk of faster disease progression in those with preexisting kidney disease. In addition, we consider the risks of developing acute altitude illness in patients with chronic kidney disease and the appropriate use of medications for the prevention and treatment of these problems.

Correlation between proteinuria level and renal morphology with special reference to electron microscopy in kidney donors

The aims of this study were to evaluate whether there is a correlation between protein level in urine and renal morphology in kidney transplant donors, as well as to detect the role of electron microscopy. For this purpose, kidney biopsies of 10 donors with urine protein levels were evaluated. Seven patients were female and three were male. Two had physiologic proteinuria (< 150 mg/24h), four had non-significant proteinuria (150-300 mg/24h), and three had significant (> 300 mg/24h) proteinuria. Serum creatinine levels were in normal ranges in all patients except for one who had a slight increase (1.76 mg/dL). Seven cases were reported to have normal or nonspecific light microscopic findings. Two of those seven cases had physiologic proteinuria, three had non-significant proteinuria, and two had significant proteinuria. One case had IgA nephropathy with significant proteinuria. One donor had early stage focal segmental glomerulosclerosis with non-significant proteinuria, and one donor had focal interstitial fibrosis with normal urine protein level. There was no statistically significant difference between score means of ultrastructural morphology of the six patients with same patients' light microscopic results and score means of light microscopic results with urine protein levels of all patients. However, there was a significant difference between score means of ultrastructural morphology with urine protein levels of those six patients. In conclusion, urine protein levels and light microscopic findings did not always reflect the detailed morphology alone and together. Therefore, combining with electron microscopic examination could be more beneficial in relieving problems occurring in long-term prognoses.

Reduction of proteinuria with angiotensin receptor blockers

Renal pathophysiology is elicited by activation of angiotensin II type 1 (AT(1)) receptors at all stages of renovascular disease. Angiotensin receptor blockers (ARBs) that specifically block the AT(1) receptor offer the potential to prevent or delay progression to end-stage renal disease independently of reductions in blood pressure. Proteinuria--an early and sensitive marker for progressive renal dysfunction--is reduced by ARB use in patients with type 2 diabetic nephropathy and microalbuminuria or macroalbuminuria. Retrospective analysis of data available from early trials has confirmed this finding and has shown that albuminuria reduction is associated with lessening of cardiovascular risk. The ARB telmisartan is equivalent to enalapril in preventing glomerular filtration rate decline, and equivalent to valsartan in reducing proteinuria. Telmisartan is more effective than conventional therapy in lowering the risk of transition to overt nephropathy in hypertensive and normotensive patients. An additive effect has been seen in smaller studies when telmisartan has been added to lisinopril therapy, and high-dose telmisartan reduces albuminuria better than low-dose telmisartan. Similar data were obtained with other ARBs such as candesartan, losartan, valsartan, or irbesartan. These data support the proposition that blockade of the renin-angiotensin system beyond that required for maximum blood pressure reduction provides optimum renal protection.

Present and future drug treatments for chronic kidney diseases: evolving targets in renoprotection

At present, there are no specific cures for most of the acquired chronic kidney diseases, and renal transplantation is limited by organ shortage, therefore present efforts are concentrated on the prevention of progression of renal diseases. There is robust experimental and clinical evidence that progression of chronic nephropathies is multifactorial; however, intraglomerular haemodynamic changes and proteinuria play a key role in this process. With a focus on renoprotection, we first examine more established therapies--such as those that modulate the renin-angiotensin-aldosterone system--that can be used for the treatment of proteinuric renal diseases. We then discuss examples of novel drugs and biologics that might be used to target the inflammatory and profibrotic process, and glomerular injury, highlighting results from recent clinical trials.

Inhibition of the renin-angiotensin system and chronic kidney disease

Chronic kidney disease (CKD), a major worldwide public-health problem which affects about 10% of the population, has an increased annual incidence rate of about 5-8%. This increased incidence is mainly due to type 2 diabetes and hypertension and the increasing incidence of elderly patients with CKD. Although the progression to end-stage renal failure (ESRF) is mainly based upon the underlying disease, comorbid conditions such as an initial low renal function, severe proteinuria, and high levels of blood pressure also play important roles in the development of ESRF. Since experimental and clinical evidence suggest that angiotensin II plays a central role in the progression of CKD, pharmacological inhibition of the renin-angiotensin-aldosteron system (RAAS) with angiotensin converting enzyme inhibitors or angiotensin II receptor antagonists has been suggested as first-line treatment for hypertension and prevention of ESRF in these patients. Aliskiren, a novel renin inhibitor is also a promising medical intervention. However, independently of the category of the drugs used, low target blood pressure levels seem to be equally or more important for the delay or prevention of CKD. In this review the results of studies with pharmacological inhibition of the RAAS in patients with diabetic and nondiabetic nephropathy is discussed.

Gender differences in predictors of the decline of renal function in the general population

We sought to identify predictors of the decline in renal function, especially those that are modifiable, in the 5488 participants of the prospective, community-based cohort study PREVEND who completed three visits during a mean follow-up of 6.5 years. The change in renal function was used as the outcome and this was calculated as the linear regression of three estimated GFR measurements obtained during follow-up. Risk factors, known to influence renal outcome in patients with primary renal diseases, were used as potential predictors in multivariate regression analyses. High systolic blood pressure and plasma glucose were found to be independent predictors for an accelerated decline in function for both genders. In males, albuminuria was the strongest independent predictor for renal function decline, whereas in females albuminuria was univariately associated only after adjustment for age. The direction of the association between cholesterol/HDL ratio and decline of renal function differed by gender. Surprisingly, in males, waist circumference was an independent predictor and positively associated with renal function outcome. These studies show that there are gender differences in the standard predictors of the decline in renal function.

New therapeutic strategies with combined renin-angiotensin system inhibitors for pediatric nephropathy

Renin-angiotensin system (RAS) inhibitors may delay progression of several chronic kidney diseases in adults. Two classes of RAS inhibitors--angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs)--have been shown to have renoprotective abilities. Despite their different mechanisms of action, these two drug classes appear to have comparable antiproteinuric and renoprotective properties. Preliminary investigations suggest that combination therapy with an ACE inhibitor and ARB offers additional benefit. Only a few studies with these drugs for treatment of pediatric nephrology have been conducted; however, their results are encouraging. Additional clinical trials are needed to confirm these results.

Outpatient management of chronic kidney disease: proteinuria, anemia and bone disease as therapeutic targets

There is increasing emphasis on chronic kidney disease (CKD), owing to its prevalence and its association with cardiovascular risk. Important issues concerning treatment of CKD are delaying its progression, improving patients' quality of life, and decreasing related mortality. These issues can be addressed with certain therapeutic options, targeting proteinuria, anemia, and secondary hyperparathyroidism. The management options and possible benefits related to treatment of these complications of CKD are reviewed.

Role of remission clinics in the longitudinal treatment of CKD

Heavy proteinuria is a major determinant of progression to ESRD for patients with chronic nephropathies and reducing proteinuria should be a key target for renoprotective therapy. In the Remission Clinic, we applied a multimodal intervention to target urinary proteins in 56 consecutive patients who had >3 g proteinuria/d despite angiotensin-converting enzyme inhibitor therapy. We compared the rate of GFR decline and incidence of ESRD in this cohort with 56 matched historical reference subjects who had received conventional therapy titrated to a target BP. During a median follow-up of 4 yr, the monthly rate of GFR decline was significantly lower in the Remission Clinic cohort (median -0.17 versus -0.56 ml/min per 1.73 m2; P < 0.0001), and ESRD events were significantly reduced (3.6 versus 30.4% reached ESRD). Follow-up BP, cholesterol, and proteinuria were lower in Remission Clinic patients than in reference subjects, such that disease remission or regression was achieved in up to 50% of patients who would have been otherwise expected to progress rapidly to ESRD on conventional therapy. Proteinuria reduction independently predicted a slower rate of GFR decline and ESRD incidence, but response to treatment differed depending on the underlying disease. Regarding safety, no patient was with drawn because of hyperkalemia. In summary, multidrug treatment titrated to urinary protein level can be safely and effectively applied to normalize proteinuria and to slow the loss of renal function significantly,especially among patients without type 2 diabetes and with otherwise rapidly progressing chronic nephropathies.

Mapping quantitative trait loci for proteinuria-induced renal collagen deposition

The progression of chronic kidney disease is a complex process influenced by genetic factors. Proteinuria is a predictor of functional deterioration and an accelerator of disease progression through renal parenchymal damage and interstitial fibrosis. To determine genetic components that might mediate renal fibrosis due to proteinuria, we mapped loci influencing the phenotype of two mouse strains differing in proteinuria-induced renal type I collagen (COLI) deposition. Collagen I deposition in 129S1/svImJ and C57BL/6J mice differs significantly among tested strains. We backcrossed 120 hemi-nephrectomized (129S1/svImJ x C57BL/6J) F1 x 129S1/svImJ backcrossed mice loaded with bovine serum albumin giving rise to proteinuria and renal COLI deposition. Quantitative trait loci (QTL) mapping was performed and our analysis identified one suggestive linkage for renal COLI deposition peaking at 87 cM near D2Mit224 (logarithm of odds: 2.41) on Chr 2. In silico analysis uncovered nine candidate genes. Hence, although more studies are needed, these QTL provide an initial cue to subsequent gene discovery, which might help unravel the genetics of renal fibrosis.

[Damage to proximal tubular epithelial cells in type 2 diabetes mellitus]

INTRODUCTION

Kidney damage from diabetes mellitus is called diabetic nephropathy. At the beginning it is a functional disorder, but later it results in an irreversible damage. The aim of this research was to establish damage to proximal tubular cells in patients with type 2 diabetes mellitus, and various degrees of proteinuria by determining the urinary N-acetyl-beta-D-glucose-aminidase and gamma-glutamyl-transferase; to compare obtained results with the results in healthy examinees; to establish the correlation between these enzymes, and to investigate their sensitivity.

MATERIAL AND METHODS

Patients with type 2 diabetes mellitus and creatinine clearence >80 ml/min were included in the research. Patients were divided into three groups, according to the degree of proteinuria. The first group included diabetics without microalbuminuria; the second--patients with proteinuria <300 mg/24 h and microalbuminuria >20 mg/24 h, and the third group included patients with proteinuria >300 mg/24 h. Healthy examinees were the control group.

RESULTS

Values of the urinary N-acetyl-beta-D-glucosaminidase activity were elevated before microalbuminuria was observed. The highest values were detected in the group of patients with microalbuminuria. Differences among the examined groups were statistically significant, which implies that this enzyme has a high diagnostic importance. Enzyme gamma-glutamyl-transferase was less sensitive in this research. The activity of this enzyme was increased only in the group of patients with proteinuria >300 mg/24h, where values increased with diabetes mellitus duration.

CONCLUSION

The increased activity of urinary N-acetyl-beta-D-glucosaminidase points to early tubular damage, and can be used as a sensitive parameter in its early detection. On the other hand, gamma-glutamyl-transferase was a less sensitive damage indicator.

Risk factors for progression in patients with early-stage chronic kidney disease in the Japanese population

OBJECTIVE

Chronic kidney disease (CKD) is an important worldwide health problem. The incidence of end-stage renal disease (ESRD) is increasing steadily around the world, however few studies have discussed the risk factors for progression in patients with early-stage CKD. Therefore, we designed a retrospective cohort study of patients with early-stage CKD to identify the risk factors influencing the annualized slope of the estimated glomerular filtration rate (eGFR).

METHODS AND PATIENTS

In this longitudinal cohort study, baseline examination was conducted in 2012 outpatients treated at the Kidney Center, Tokyo Women's Medical University. Follow-up examinations were completed in 485 patients with stage 1 and stage 2 CKD within the study period (2002-2007). The conventional risk factors for CKD progression, such as proteinuria, blood pressure, serum triglyceride, serum HDL, fasting plasma glucose, smoking habit, hypertension or treatment with antihypertensive medication and body mass index, were examined. The annualized eGFR slope was calculated at the start and end of the study period. Multivariate analysis was performed to determine the associations of the eGFR slope with the predisposing risk factors.

RESULTS

The mean annualized eGFR slope was -1.64 mL/min/1.73 m(2)/year. Concerning the relationship between etiology and the GFR decreasing slope, IgA nephropathy was defined as the worst (-1.80 mL/min/year) due to the high ratio of proteinuria. Proteinuria (-2.13 mL/min/1.73 m(2)/year, p=0.005), smoking habit (-2.06 mL/min/1.73 m(2)/year, p=0.014), low serum HDL (-1.95 mL/min/1.73 m(2)/year, p=0.035), and hypertension (-1.73 mL/min/1.73 m(2)/year, p=0.045) were all significantly related to the eGFR slope. The estimated GFR for the highest BMI quartile was significantly higher than that of the eGFR for the lowest BMI.

CONCLUSION

Proteinuria, smoking habit, hypertension and low HDL were clearly related to accelerated disease progression in patients with early-stage CKD. Therefore, aggressive treatment of these risk factors is essential in the early stages of CKD.

Supratherapeutic doses of angiotensin receptor blockers to decrease proteinuria in patients with chronic kidney disease

An important endpoint in treating chronic kidney disease, a prevalent disease that can lead to kidney failure and cardiovascular disease, is reducing proteinuria. Proteinuria is an independent risk factor for disease progression and the development of cardiovascular disease and is a key factor that can be used to guide therapy designed to maximize kidney protection. Proteinuria is targeted by using pharmacologic agents that suppress the renin-angiotensin-aldosterone system (RAAS), a regulator of intravascular volume and blood pressure; this has been shown to decrease proteinuria, slow disease progression, and improve coronary disease outcome, independent of effects on blood pressure. The efficacy of RAAS blockers, including angiotensin receptor blockers and angiotensin-converting enzyme inhibitors, may be limited by currently recommended doses, which are based on treatment of hypertension. Data are now emerging from clinical trials demonstrating that use of 'supratherapeutic doses' (doses greater than those approved for lowering blood pressure), compared with standard doses, has favorable safety, tolerability, and efficacy in reducing proteinuria in both diabetic and nondiabetic patients with chronic kidney disease. Supratherapeutic dosing may be a valuable approach for optimizing RAAS blockade and providing renoprotection.

Remission of proteinuria improves prognosis in IgA nephropathy

Proteinuria has been shown to be an adverse prognostic factor in IgA nephropathy. The benefit of achieving a partial remission of proteinuria, however, has not been well described. We studied 542 patients with biopsy-proven primary IgA nephropathy in the Toronto Glomerulonephritis Registry and found that glomerular filtration rate (GFR) declined at -0.38 +/- 0.61 ml/min per 1.73 m2/mo overall, with 30% of subjects reaching end-stage renal disease. Multivariate analysis revealed that proteinuria during follow-up was the most important predictor of the rate of GFR decline. Among the 171 patients with <1 g/d of sustained proteinuria, the rate of decline was 90% slower than the mean rate. The rate of decline increased with the amount of proteinuria, such that those with sustained proteinuria >3 g/d (n = 121) lost renal function 25-fold faster than those with <1 g/d. Patients who presented with > or =3 g/d who achieved a partial remission (<1 g/d) had a similar course to patients who had < or =1 g/d throughout, and fared far better than patients who never achieved remission. These results underscore the relationship between proteinuria and prognosis in IgA nephropathy and establish the importance of remission.

Cyclosporin in idiopathic glomerular disease associated with the nephrotic syndrome : workshop recommendations

Management of idiopathic glomerular disease associated with nephrotic syndrome (INS) remains controversial and one of the most complex areas relates to utilization of the drug cyclosporin. This is despite its demonstrated effectiveness in several histologic types of the INS in randomized controlled trials. Cyclosporin is effective in inducing remission of proteinuria in approximately 80% of steroid-sensitive cases of minimal change disease (MCD). Cyclosporin is also effective in both the induction of remission and long-term preservation of renal function in steroid-dependent/-resistant MCD and steroid-resistant focal segmental glomerulosclerosis (FSGS). The overall response rate in FSGS is lower than in MCD, and long-term therapy (>12 months) may be required to both achieve remission and sustain it. Cyclosporin therapy is also of benefit in reducing proteinuria in 70-80% of patients with steroid-resistant membranous nephropathy (MGN). In MGN, the maximum benefit is often delayed compared to MCD (>12 weeks). Cyclosporin is generally well tolerated and safe. The major concern remains the nephrotoxicity, but with careful monitoring of the patient's renal function; minimizing the maintenance dose and utilizing repeat renal biopsy in those receiving long-term therapy, this risk can be minimized. The algorithms have been developed derived from the best evidence in the literature in each of the histologic types to help provide a guide to the integration of cyclosporin into the management of INS for the practicing nephrologist.

Pharmacological management of renal fibrotic disease

Chronic kidney diseases frequently advance to end-stage renal failure, and the number of patients affected is steadily increasing worldwide. At the molecular level, progression of renal insufficiency correlates closely with ongoing pathological matrix protein expansion (i.e., renal fibrosis), in a manner independent of the underlying disorder. Overactivity of the renin-angiotensin system and of the TGF-beta system have been identified as key mediators of kidney matrix accumulation, and are principal targets in the management of chronic renal disease. This review provides a recent overview of the therapeutic options that are clinically established, and of novel molecular strategies that will approach clinical practice in the near future.

Restricted protein diet is associated with decrease in proteinuria: consequences on the progression of renal failure

OBJECTIVE

Reduction of proteinuria is associated with a slower progression of renal failure. We questioned whether the change in proteinuria in response to a supplemented very low protein diet (SVLPD), which is known to reduce proteinuria, could function as a marker of the potential renoprotective effect of an SVLPD.

DESIGN AND PATIENTS

In the 220 consecutive patients of our previously published cohort, the glomerular filtration rate (GFR) was assessed every 3 months using the (51)Cr-EDTA method. Seventy-eight patients (mean age 52 +/- 17 years, body mass index 23 +/- 3 kg/m(2), GFR 15 +/- 6 mL/min) exhibited a proteinuria more than 1 g per day at the start of the regimen. Mean protein intake assessed by urinary nitrogen appearance was 0.42 +/- 0.24 g/kg per day at 4 months. The median follow-up was 24 months.

RESULTS

Proteinuria decreased significantly after patients were treated with an SVLPD. The maximum mean percent reduction was attained at 3 months (47% +/- 27%), was not influenced by the levels of baseline proteinuria, and was similar in patients receiving or not receiving angiotensin-converting enzyme inhibition at the start of the study. The percent reduction and the residual proteinuria at 3 months predicted the rate of the later GFR decline. GFR decline was significantly lower in patients whose reduction in proteinuria at 3 months was higher than 50% (0.42 +/- 0.37 mL/min/mo vs. 0.10 +/- 0.15 mL/min/mo and 1.0 +/- 0.6 mL/min/mo vs. 0.15 +/- 0.19 mL/min/mo, P < .001 in patients with proteinuria higher or lesser than 3 g/d at start, respectively).

CONCLUSION

These results do not differ from those reported with therapies antagonizing angiotensin II formation and/or activity aiming at reducing proteinuria in chronic renal diseases.

Changes in renal function following administration of oral sodium phosphate or polyethylene glycol for colon cleansing before colonoscopy

Changes in renal function were compared in patients receiving oral sodium phosphate (NaP) for colon cleansing and those receiving large-volume polyethylene glycol (PEG) solution to determine whether oral NaP resulted in frequent renal damage that had gone clinically undetected. From 1995 to 2004, a cohort of consecutive patients who had serum creatinine (Cr) drawn immediately before colonoscopy and again after subsequent procedures three months to nine years later (almost 80% of patients between the first and fifth year) were identified. Chronic renal failure (CRF) was defined as an abnormal Cr at repeat measurement or an abnormal Cr clearance as estimated by the Cockroft-Gault equation at the time of repeat Cr measurement. Medications and medical comorbid conditions were recorded. Seven hundred sixty-seven patients (51% female and 49% male; 81% oral NaP and 19% PEG) with normal baseline Cr levels were identified through the endoscopy unit database at the Hotel Dieu Hospital, Queen's University (Kingston, Ontario). Of these, 55 (7%) developed CRF. Forty-two (6.8%) patients receiving oral NaP developed renal failure compared with 13 patients (8.7%) receiving PEG (Fisher's exact test; P=0.382), but the magnitude of CRF was small in each group (Cr level lower than 160 mumol/L). Using logistic regression analysis with the choice of preparation, medications and medical comorbid conditions as independent variables, only age and blood pressure were predictive of the development of renal failure (P=0.014 and P=0.001, respectively). Baseline Cr clearance was similar in both the NaP and PEG groups and the absolute difference after colonoscopy did not differ. The present study concluded that the ingestion of oral NaP for colon cleansing before colonoscopy did not result in frequent renal damage that went clinically undetected.

25-Hydroxyvitamin D levels and albuminuria in the Third National Health and Nutrition Examination Survey (NHANES III)

BACKGROUND

Albuminuria is a risk factor for chronic kidney disease progression, end-stage renal disease, cardiovascular events, and mortality. Animal studies suggested that vitamin D insufficiency may contribute to the pathogenesis of albuminuria.

STUDY DESIGN

Cross-sectional study.

SETTING & PARTICIPANTS

15,068 adults participating in the Third National Health and Nutrition Examination Survey.

PREDICTOR

Serum 25-hydroxyvitamin D concentration, examined in quartiles.

OUTCOMES & MEASUREMENTS

Albuminuria, defined using established sex-specific cutoff values for urine albumin-creatinine ratio (25 to 2,999 mg/g for women, 17 to 2,999 mg/g for men).

RESULTS

A stepwise increase in the prevalence of albuminuria was observed with decreasing quartiles of vitamin D concentration: 8.9%, 11.5%, 13.7%, and 15.8% (P < 0.001). Adjusting for age, sex, race/ethnicity, region and season of measurement, smoking status, body mass index, and estimated glomerular filtration rate, relative risks for albuminuria by decreasing quartile of vitamin D concentration were 1.00 (reference group), 1.14 (95% confidence interval, 0.95 to 1.37), 1.22 (95% confidence interval, 1.03 to 1.45), and 1.37 (95% confidence interval, 1.10 to 1.71; P = 0.006). Additionally adjusting for blood pressure and diabetes mellitus, these risks were somewhat attenuated and retained statistical significance.

LIMITATIONS

The cross-sectional design of this study does not allow demonstration of temporal or causal relationships between vitamin D and albuminuria.

CONCLUSIONS

Additional studies are needed to clarify the relationship of vitamin D with albuminuria and determine whether vitamin D therapy prevents or improves markers of kidney and cardiovascular disease.

CD36 is a novel and potential anti-fibrogenic target in albumin-induced renal proximal tubule fibrosis

Albumin is not only a risk factor for diabetic nephropathy (DN), but also a therapeutic target. Hence, scientists have long sought ways to elucidate the interactions between albumin and diabetic renal tubule fibrosis. CD36, a surface receptor for thrombospondin-1, has been reported to interact with latent transforming growth factor-beta1 (TGF-beta1) and activate its fibrogenic bioactivity. This study elucidates the interactions between CD36 and renal tubule fibrosis. LLC-PK1 cells were applied to represent renal proximal tubule cells. The expression of CD36 was evaluated by flow cytometry. Fibronectin was assayed by Western blot and enzyme-linked immunosorbent assay (ELISA). Bioactive TGF-beta1 was assayed by ELISA. We demonstrated that albumin was shown significantly to inhibit cell growth without affecting hypertrophy status since protein content and cell size remained unaffected under albumin treatment. Moreover, albumin dose-dependently (0, 1, or 10 mg/ml) enhanced the secretion of bioactive TGF-beta1 and fibronectin with the upregulation of CD36. Intriguingly, CD36 siRNA, a potent silencer for CD36 effectively suppressed the albumin-induced increase in CD36, TGF-beta1, and even fibronectin level. Accordingly, albumin is a pro-fibrogenic factor for proximal tubule cells since albumin per se markedly upregulated the expression of TGF-beta1 and fibronectin. Most importantly, CD36 may mediate albumin-induced cellular fibrosis since CD36 siRNA appeared to have anti-fibrosis effects. This work suggests that CD36 is a novel and potential therapeutic target for diabetic renal tubule fibrosis.

Albuminuria: a target for treatment of type 2 diabetic nephropathy

Both renal and cardiovascular morbidity and mortality is increased markedly in patients with type 2 diabetes. Besides the classic risk factors and markers such as glucose, blood pressure, blood lipid profile, and lifestyle (smoking, overweight), novel risk markers are identified, among them urine albumin excretion. Levels of urinary albumin excretion greater than normal are observed frequently in patients with type 2 diabetes. Moderately increased levels of albuminuria, so-called microalbuminuria, are predictive both for progressive renal function loss to diabetic nephropathy, and for cardiovascular morbidity and mortality: the higher the albuminuria level, the more chance of renal and cardiovascular complications. More advanced levels of albuminuria (overt albuminuria) are observed in patients in the diabetic nephropathy state. In this condition, renal and cardiovascular risk are extremely high, and again one may observe that the level of albumin excretion is predictive of renal and cardiovascular outcome. Several drug strategies decrease the level of urinary albumin excretion in type 2 diabetic patients. Data on using drugs that intervene in the renin-angiotensin-aldosterone-system (RAAS) are the most extensive and conclusive. RAAS intervention is a very effective strategy to decrease the amount of albumin in the urine, independent from the blood pressure decreasing characteristics of the treatment. RAAS intervention is associated with long-term renal and cardiovascular protection. Importantly, the degree of short-term albuminuria decrease is associated with the degree of renal and cardiovascular protection: the more albuminuria reduction, the more protection. The protective predictive power of the albuminuria effect of RAAS intervention is not related to (or dissociated from) the blood pressure decreasing effect of these drugs. The protective effect of RAAS intervention is present at normoalbuminuric, microalbuminuric, and overt albuminuria levels. This makes albuminuria a target for therapy in type 2 diabetes. New drug strategies that decrease or prevent albuminuria without affecting other risk factors currently are being tested, and not only will add to underscoring the need to treat albuminuria as a separate target, but also will assist in reducing the enormous residual risk burden of individual diabetic patients.

[Tubular kidney function in patients with type 2 diabetes mellitus, microalbuminuria and proteinuria]

INTRODUCTION

Diabetes mellitus (DM) and hypertension are the most frequent causes of kidney function damage. Many different tests are developed to detect reversible functional kidney changes (detection of microalbuminuria and selective urinary enzymes).

OBJECTIVE

The aim of our study was to examine tubular kidney function in type 2 DM patients with different proteinuria levels, and to compare these results with healthy people.

METHOD

The patients with type 2 DM and creatinine clearance >80 ml/min were included in the study. According to the levels of proteinuria, the patients were classified in three groups: group I--patients with proteinuria <300 mg/24 h, and no microalbuminuria; group II--the patients with proteinuria <300 mg/24 h and microalbuminuria >20 mg/24 h; and group III--the patients with proteinuria >300 mg/24 h. The control group consisted of healthy subjects.

RESULTS

The study revealed that in type 2 DM patients and normal global kidney function, fractional excretions of sodium, potassium, and phosphates as well as renal phosphate concentrations were not adequately sensitive markers to detect damage in tubular kidney function in DM. There were some changes of urate fractional excretion in these patients: this value was significantly lower in patients with microalbuminuria compared with those with proteinuria >300 mg/24 h, as well as in the control group (p < 0.05). Hormone dependent tubular kidney activity, urinary osmolarity, and urea fractional excretion in all patients were within normal ranges.

CONCLUSION

It is evident that routine laboratory analyses are not sensitive markers to detect early changes of kidney function in type 2 DM.

Comparison of higher dose of losartan treatment with losartan plus carvedilol and losartan plus ramipril in patients with glomerulonephritis and proteinuria

BACKGROUND

Proteinuria may cause a worsening of accompanying renal disease or even lead to glomerulosclerosis. There is no data about the effect of carvedilol on patients with proteinuric (>0.5 g/day) glomerulonephritis. This study aimed to compare the effects of carvedilol with ramipril and losartan in patients with proteinuric glomerulonephritis.

METHODS

Twenty-one glomerulonephritis patients were followed for 12 months. Patients were divided into three groups. All patients were treated with losartan 50 mg once daily for two weeks. After two weeks (baseline), patients were given additional medications: 50 mg losartan, 5 mg ramipril, and 25 mg carvedilol were given additionally to the patients in groups 1, 2, and 3 respectively.

RESULTS

Baseline mean proteinuria values of patients in groups 1, 2 and 3 were 1.6 +/- 1.1 g/day, 2.1 +/- 1.3 g/day, and 1.4 +/- 1.2 g/day, respectively. These values decreased to 0.5 +/- 0.7 g/day, 0.6 +/- 0.7 g/day, and 0.9 +/- 0.9 g/day, respectively, at the end of the 12th month. These results were statistically significant only in group 1 (p = 0.04). The rational variation of proteinuria between the first and 12th month of losartan, ramipril, and carvedilol were -61%, -62%, and -27%, respectively. The decreases in blood pressures between baseline and the first, sixth, and twelfth-month measurements were significant in all groups.

CONCLUSIONS

Thee results showed that angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (AT1ras) provide marked decreases in proteinuria, making their use indisputable in patients with glomerulonephritis. Carvedilol was not found to be as effective as ACEIs and AT1ras in decreasing proteinuria and preserving renal function.

Monitoring of cadmium toxicity in a Thai population with high-level environmental exposure

This study evaluated the utility of single and combined measurements of cadmium toxicity markers for surveillance purposes, using a sample of 224 individuals, 30-87 years of age, who were residents of cadmium polluted area in Mae Sot District, Tak Province, Thailand. Urinary cadmium levels excreted by them ranged between 1 and 58 microg/g creatinine with geometric mean of 8.2 microg/g creatinine which was 16-fold greater than the average for the general Thai population of 0.5 microg/g creatinine. The urinary markers evaluated were total protein, albumin, N-acetyl-beta-D-glucosaminidase (NAG), lysozyme, beta2-microglobulin (beta2-MG) and alpha1-microglobulin (alpha1-MG). Among these markers, only NAG showed a positive correlation with urinary cadmium in both male and female subjects with and without disease (r=0.43-0.71). Further, the prevalence rates for urinary NAG above 8 units/g creatinine (NAG-uria) increased with exposure levels in a dose dependent manner (p=0.05) among subjects with disease. In contrast, however, increased prevalence of beta2-MG above 0.4 mg/g creatinine (beta2-MG-uria) was associated with cadmium above 5 microg/g creatinine only in those without disease (POR=10.6 and 7.8 for 6-10 and >10 microg/g creatinine). Prevalence rates for abnormal excretion of all other markers, except albumin, were markedly increased among those having beta2-MG-uria with and without disease (chi2-test, p<or=0.001-0.02). Thus, urinary beta2-MG and NAG should be used together with urinary cadmium in the monitoring of renal toxicity in a population exposed to high-level cadmium coupled with high prevalence of chronic diseases.

The role played by endocytosis in albumin-induced secretion of TGF-beta1 by proximal tubular epithelial cells

Proteinuria predicts the decline of renal function in chronic kidney disease. Reducing albuminuria has been shown to be associated with a reduction in this rate of decline. Proximal tubular epithelial cells (PTECs), when exposed to albumin produce matrix proteins, proinflammatory and profibrotic cytokines like TGF-beta(1). Some of these effects are dependent on endocytosis of albumin by PTECs. However, conditions like diabetic nephropathy, believed to be associated with reduced albumin endocytosis, are associated with interstitial fibrosis. Moreover, megalin, the putative albumin binding receptor in PTECs, has potential signaling motifs in its cytoplasmic domain, suggesting its ability to signal in response to ligand binding from the apical surface of PTECs. Hence, we looked to see whether albumin-induced secretion of TGF-beta(1) by PTECs is dependent on albumin endocytosis or whether it could occur in the absence of albumin endocytosis. We studied the production of TGF-beta(1) in two accepted models of PTECs, opossum kidney cells and human kidney cell clone-8 cells, with widely varying degrees of endocytosis. We then studied the effect of inhibiting albumin endocytosis with various inhibitors on albumin-induced TGF-beta(1) secretion. Our results indicate that albumin-induced TGF-beta(1) secretion by PTECs does not require albumin endocytosis and therefore the mechanism for the induction of some profibrotic responses by albumin may differ from those required for some of the inflammatory responses. Moreover, we found that albumin-induced TGF-beta(1) secretion by PTECs is not dependent on its interaction with megalin.

An introduction to biomarkers: applications to chronic kidney disease

Diagnosis and management of chronic kidney disease (CKD) will be characterized in the future by an increasing use of biomarkers-quantitative indicators of biologic or pathologic processes that vary continuously with progression of the process. "Classical" biomarkers of CKD progression include quantitative proteinuria, the percentage of sclerotic glomeruli or fractional interstitial fibrosis. New candidate biomarkers (e.g., urinary proteomic patterns) are being developed based on both mechanistic and "shotgun" approaches. Validation of potential biomarkers in prospective studies as surrogate endpoints for hard clinical outcomes is often complicated by the long lag time to the ultimate clinical outcome (e.g., end-stage renal disease). The very dense data sets that result from shotgun approaches on small numbers of patients carry a significant risk of model overfitting, leading to spurious associations. New analytic methods can help to decrease this risk. It is likely that clinical practice will come to depend increasingly on multiplex (vector) biomarkers used in conjunction with risk markers in early diagnosis as well as to guide therapy.

Effect of indomethacin and selective cyclooxygenase-2 inhibitors on proteinuria and renal function in patients with AA type renal amyloidosis

AIMS

Because the cardiovascular system (CVS) side-effects of cyclooxygenase-2 (COX-2) selective inhibitors have recently been questioned, we aimed to compare the renal and haemodynamic effects of cyclooxygenase selective (celecoxib and rofecoxib) and non-selective non-steroidal anti-inflammatory drugs (NSAIDs) (indomethacin) in patients with renal amyloidosis secondary to rheumatological diseases who required anti-inflammatory agents and are taking maximum tolerable dose of angiotensin-converting enzyme inhibitors.

METHODS

The present study was performed on 11 patients with stable proteinuria who were diagnosed as AA amyloidosis secondary to rheumatological diseases confirmed by renal biopsies. The study had three consecutive stages (celecoxib 200 mg/day; indomethacin 100 mg/day; rofecoxib 25 mg/day.) Each was given for 4 weeks and a wash-out phase of 3 weeks was allowed between consecutive stages.

RESULTS

Although the decrease of proteinuria in the celecoxib period was higher than in the rofecoxib and indomethacin periods, the difference was not statistically significant. No statistically significant differences were found between serum urea, creatinine, creatinine clearance and urinary sodium excretion.

CONCLUSION

In this study, no differences were found between indomethacin and the two selective COX-2 inhibitors in respect to proteinuria and renal functions in 11 patients with renal amyloidosis secondary to rheumatological diseases with varying degrees of proteinuria. Routine doses of NSAIDs brought no additional benefit to the ACE inhibitor use in terms of proteinuria and renal functions. The use of selective COX-2 inhibitors should be limited to their anti-inflammatory and analgesic effects in this population.

Efficacy of omega-3 fatty acids in children and adults with IgA nephropathy is dosage- and size-dependent

Previous studies that have evaluated fish oil preparations in patients with IgA nephropathy (IgAN) have produced a wide range of conclusions. Proposed explanations for these discordant results have not provided a unifying hypothesis. Results from two clinical trials were analyzed to examine whether there is a dosage-dependent effect of Omacor, a purified preparation of omega-3 fatty acids, in patients with IgAN. Whether changes in the level of proteinuria and plasma phospholipid fatty acid profiles were dependent on the dose of Omacor factored by body size was determined. In a post hoc analysis of the first trial results, correlations were found between (1) phospholipid eicosapentaenoic acid (EPA)/arachidonic acid (AA) and docosahexaenoic acid (DHA)/AA ratios and the dosage of Omacor, expressed as milligrams per kilogram of body weight (r = 0.78, P < 0.001 for EPA/AA; r = 0.86, P < 0.001 for DHA/AA), (2) phospholipid EPA/AA and DHA/AA levels and percentage change in urine protein/creatinine ratio after 21 to 24 mo of therapy (r = -0.50, P = 0.02 for EPA/AA; r = -0.52, P = 0.01 for DHA/AA), and (3) dosage of Omacor per kilogram of body weight and change in proteinuria after 21 to 24 mo (r = -0.50, P = 0.02). A similar relationship was observed between urine protein/creatinine ratio and dosage of Omacor per kilogram of body weight in trial 2 (r = -0.38, P < 0.001). It is concluded from these data that the effect of Omacor on proteinuria in patients with IgAN is dosage dependent and is associated with a dosage-dependent effect of Omacor on plasma phospholipid EPA and DHA levels.

Association of laboratory data and death within one month in cats with chronic renal failure

OBJECTIVES

To retrospectively compare the data taken at the first visit of 34 cats with chronic renal failure surviving more than one month (surviving group) and 16 cats dying within one month (non-surviving group).

METHODS

Records were collected on cats with chronic renal failure presented to a private veterinary practice in Nagoya, Japan, from March 1996 to March 2005. All cats with chronic renal failure diagnosed on the basis of case histories, clinical signs (such as, lethargy, anorexia, loss of bodyweight and vomiting) and a high plasma creatinine (>180 micromol/l) were included in the study.

RESULTS

Plasma creatinine, urea nitrogen, inorganic phosphate, packed cell volume and urine protein/creatinine ratio were significantly different between cats of the surviving and non-surviving groups. In the surviving group, survival statuses were recorded, and laboratory data was obtained within one month before death in 13 cats. In the 13 cats, plasma creatinine, packed cell volume and urine protein/creatinine ratio showed significant differences between the data taken within one month before death and that taken at first visit, and only urine protein/creatinine ratio exhibited a consistent alteration (increase) in relation to first visit data.

CLINICAL SIGNIFICANCE

These results indicated that plasma creatinine, urea nitrogen, inorganic phosphate, packed cell volume and urine protein/creatinine ratio were associated with death within one month and urine protein/creatinine ratio was most likely to be associated with mortality in cats with chronic renal failure.