The course of kidney function in type 2 (non-insulin-dependent) diabetic patients with diabetic nephropathy

Accuracy of glomerular filtration rate estimation using creatinine and cystatin C for identifying and monitoring moderate chronic kidney disease: the eGFR-C study

Background

Estimation of glomerular filtration rate using equations based on creatinine is widely used to manage chronic kidney disease. In the UK, the Chronic Kidney Disease Epidemiology Collaboration creatinine equation is recommended. Other published equations using cystatin C, an alternative marker of kidney function, have not gained widespread clinical acceptance. Given higher cost of cystatin C, its clinical utility should be validated before widespread introduction into the NHS.

Objectives

Primary objectives were to: (1) compare accuracy of glomerular filtration rate equations at baseline and longitudinally in people with stage 3 chronic kidney disease, and test whether accuracy is affected by ethnicity, diabetes, albuminuria and other characteristics; (2) establish the reference change value for significant glomerular filtration rate changes; (3) model disease progression; and (4) explore comparative cost-effectiveness of kidney disease monitoring strategies.

Design

A longitudinal, prospective study was designed to: (1) assess accuracy of glomerular filtration rate equations at baseline (n = 1167) and their ability to detect change over 3 years (n = 875); (2) model disease progression predictors in 278 individuals who received additional measurements; (3) quantify glomerular filtration rate variability components (n = 20); and (4) develop a measurement model analysis to compare different monitoring strategy costs (n = 875).

Setting

Primary, secondary and tertiary care.

Participants

Adults (≥ 18 years) with stage 3 chronic kidney disease.

Interventions

Estimated glomerular filtration rate using the Chronic Kidney Disease Epidemiology Collaboration and Modification of Diet in Renal Disease equations.

Main outcome measures

Measured glomerular filtration rate was the reference against which estimating equations were compared with accuracy being expressed as P30 (percentage of values within 30% of reference) and progression (variously defined) studied as sensitivity/specificity. A regression model of disease progression was developed and differences for risk factors estimated. Biological variation components were measured and the reference change value calculated. Comparative costs of monitoring with different estimating equations modelled over 10 years were calculated.

Results

Accuracy (P30) of all equations was ≥ 89.5%: the combined creatinine-cystatin equation (94.9%) was superior (p < 0.001) to other equations. Within each equation, no differences in P30 were seen across categories of age, gender, diabetes, albuminuria, body mass index, kidney function level and ethnicity. All equations showed poor (< 63%) sensitivity for detecting patients showing kidney function decline crossing clinically significant thresholds (e.g. a 25% decline in function). Consequently, the additional cost of monitoring kidney function annually using a cystatin C-based equation could not be justified (incremental cost per patient over 10 years = £43.32). Modelling data showed association between higher albuminuria and faster decline in measured and creatinine-estimated glomerular filtration rate. Reference change values for measured glomerular filtration rate (%, positive/negative) were 21.5/-17.7, with lower reference change values for estimated glomerular filtration rate.

Limitations

Recruitment of people from South Asian and African-Caribbean backgrounds was below the study target.

Future work

Prospective studies of the value of cystatin C as a risk marker in chronic kidney disease should be undertaken.

Conclusions

Inclusion of cystatin C in glomerular filtration rate-estimating equations marginally improved accuracy but not detection of disease progression. Our data do not support cystatin C use for monitoring of glomerular filtration rate in stage 3 chronic kidney disease.

Trial registration

This trial is registered as ISRCTN42955626.

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: 11/103/01) and is published in full in Health Technology Assessment; Vol. 28, No. 35. See the NIHR Funding and Awards website for further award information.

Clinical Profile of Nonproteinuric Kidney Disease in Type 2 Diabetic Patients in India

Background

Diabetic kidney disease (DKD) is the commonest cause of end-stage renal disease (ESRD) across the world. Development of microalbuminuria is the earliest marker of DKD and predicts progressive decline in estimated glomerular filtration rate (eGFR). However, recent evidence has suggested that a significant proportion of type 2 diabetic patients have chronic kidney disease (CKD) without proteinuria.

Methods

In this single-center, prospective observational study, 400 consecutive type 2 diabetic patients with either overt proteinuria (>500 mg/day) and/or renal dysfunction eGFR <60 ml/min/1.73 m2) were recruited. Baseline demographic and clinical data were recorded. eGFR and proteinuria were recorded at 6 months and 1 year. Patients with proteinuric (proteinuria >0.5 g/day) and nonproteinuric phenotypes were compared for progression of renal dysfunction in terms of doubling of serum creatinine and need for dialysis.

Results

In our study cohort, 106 (26.5%) were nonproteinuric. Both the groups were similar in terms of gender, duration of diabetes, comorbidities, body mass index (BMI), blood pressure control, and glycemic control. The nonproteinuric group was older (56.5 ± 2.1 vs. 54.7 ± 11.6 years, P = 0.012), had lesser prevalence of diabetic retinopathy (49 [46.2%] vs. 218 [74.1%], P < 0.001), higher hemoglobin levels (11.3 ± 1.7 vs. 10.5 ± 2.0 g/dl, P < 0.001), and higher cholesterol levels (169.3 ± 43.3 vs 157.1 ± 58.1 mg/dl, P = 0.025). The nonproteinuric phenotype had higher eGFR at baseline, 6 months, and 1 year. However, doubling of serum creatinine (10 [9.4%] vs. 48 [16.3%]) and progression to ESRD (5 [4.7%] vs. 19 [6.5%], P = 0.159) were not different between the two phenotypes.

Conclusion

Nonproteinuric DKD is common. Patients with nonproteinuric DKD tend to be older with a slower decline in eGFR.

Proteinuria Indicates Decreased Normal Glomeruli in ANCA-Associated Glomerulonephritis Independent of Systemic Disease Activity

Background: Renal involvement is a common and severe complication of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), potentially resulting in a pauci-immune necrotizing and crescentic ANCA glomerulonephritis (GN) with acute kidney injury (AKI), end-stage renal disease (ESRD) or death. There is recent evidence that the degree of proteinuria at diagnosis is associated with long-term renal outcome in ANCA GN. Therefore, we here aimed to systematically describe the association between proteinuria and clinicopathological characteristics in 53 renal biopsies with ANCA GN and corresponding urinary samples at admission. Methods: A total number of 53 urinary samples at admission and corresponding renal biopsies with confirmed renal involvement of AAV were retrospectively included from 2015 to 2021 in a single-center study. Results: Proteinuria correlated with myeloperoxidase (MPO) subtype, diagnosis of microscopic polyangiitis (MPA) and severe deterioration of kidney function. Proteinuria was most prominent in sclerotic class ANCA GN and ANCA renal risk score (ARRS) high risk attributed to nonselective proteinuria, including both glomerular and tubular proteinuria. Finally, there was no association between proteinuria and systemic disease activity, suggesting that proteinuria reflected specific renal involvement in AAV rather that systemic disease activity. Conclusions: In conclusion, proteinuria correlated with distinct clinicopathological characteristics in ANCA GN, mostly attributed to a reduced fraction of normal glomeruli. Furthermore, proteinuria in ANCA GN reflected specific renal involvement in AAV rather than systemic disease activity. Therefore, urinary findings could further improve our understanding of mechanisms promoting kidney injury and progression of ANCA GN.

The role of sodium glucose cotransporter-2 (SGLT-2) inhibitors in heart failure and chronic kidney disease in type 2 diabetes

Background: Heart failure (HF) and chronic kidney disease (CKD) are responsible for substantial morbidity and mortality in individuals with type 2 diabetes (T2D). Methods: This review discusses the significance of these comorbidities of T2D and current options for managing them, with a focus on sodium-glucose cotransporter-2 (SGLT-2) inhibitors. Based on a focused literature search of cardiovascular outcomes trials (CVOTs), this review assessed the effects of SGLT-2 inhibitors in individuals with T2D with or without established cardiovascular disease (CVD). Results: In addition to effective glycemic control and weight loss, SGLT-2 inhibitor treatment of T2D prevents adverse cardiovascular and renal outcomes in individuals with and without these comorbidities. Reduced rate of hospitalization due to HF (HHF) and improved renal outcomes appear to be class effects of SGLT-2 inhibitors. Reduction in CV events may be more significant in individuals with established cardiovascular disease. Conclusions: CVOTs and other studies confirm that the SGLT-2 inhibitors, mostly used in combination with other glucose-lowering drugs, offer several clinical benefits beyond improved glycemic control. These include reducing HHF risk and improving renal outcomes. HF and renal benefits are observed in individuals with and without established CVD, which may simplify therapeutic selection. Ongoing SGLT-2 inhibitor CVOTs will help clarify the potential of these drugs to treat T2D comorbid with different forms of HF (HF with preserved vs reduced ejection fraction) and different degrees of renal dysfunction, and in individuals with T2D vs pre-diabetes or normal glucose metabolism.

Clinical Efficacy and Safety of Jinshuibao Combined With ACEI/ARB in the Treatment of Diabetic Kidney Disease: A Meta-Analysis of Randomized Controlled Trials

OBJECTIVE

The present study aims to compare the relative efficacy and safety of jinshuibao (JSB) combined with angiotensinconverting enzyme inhibitors/angiotensin receptor blockers (ACEIs/ARBs) in the treatment of diabetic kidney disease.

METHODS

We searched EMBASE, MEDLINE, PubMed, China National Knowledge Internet, the Chinese Biomedical Database, and Wanfang database for articles from the building of the database to September 2018.

RESULTS

Fifty-one randomized controlled trials with 3,955 participants were included. The meta-analysis indicated that compared with the controls, JSB combined with ACEI/ARB group could remarkably improve the overall response rate (odds ratio 4.91; 95% confidence interval [CI] 3.32-7.25) and reduce 24 h proteinuria (mean difference [MD] -0.16; 95% CI -0.19 to -0.13), urine albumin excretion ratio (MD -28.20; 95% CI -36.30 to -20.11), serum creatinine (MD -13.84; 95% CI -18.01 to -9.68), blood urea nitrogen (MD -1.00; 95% CI -1.36 to -0.63), systolic blood pressure (MD -4.57; 95% CI -6.78 to -2.37), diastolic blood pressure (MD -3.96; 95% CI -5.73 to -2.19), fasting blood glucose (MD -0.85; 95% CI -1.45 to -0.24), hemoglobin A1c (MD -0.52; 95% CI -0.83 to -0.21), serum total cholesterol (MD -0.53; 95% CI -0.86 to -0.20), and triglyceride (MD -0.53; 95% CI -0.55 to -0.51).

CONCLUSIONS

JSB combined with ACEI/ARB in the treatment of diabetic kidney disease is superior to the single application of ACEI/ARB.

Prognosis and treatment of diabetic nephropathy: Recent advances and perspectives

Approximately 20 to 40% of patients with type 1 or type 2 diabetes develop diabetic kidney disease. It is a clinical syndrome characterized by persistent albuminuria (>300mg/24h, or 300mg/g creatinine), a relentless decline in glomerular filtration rate, raised arterial blood pressure and enhanced cardiovascular morbidity and mortality. The natural course of classical diabetic nephropathy is initially microalbuminuria or moderately increased urine albumin excretion (30-300mg/g creatinine). Untreated microalbuminuria may then rise gradually, reaching severely increased albuminuric (macroalbuminuria) over 5 to 15 years. Glomerular filtration rate then begins to decline and end-stage renal failure is reached without treatment in 5 to 7 years. Regular, systematic screening for diabetic kidney disease is needed to identify patients at risk for, or with presymptomatic stages of diabetic kidney disease. Multifactorial intervention targeting glucose, lipids and blood pressure including blockade of renin angiotensin system and lifestyle, has improved renal and cardiovascular prognosis and reduced mortality with 50%. Recent data suggest beneficial pleiotropic effects on renal endpoint with new glucose lowering agents. It is also being investigated if blocking aldosterone could be an option as a potential new treatment. Thus, although diabetic nephropathy remains a major burden, prognosis has improved and new options for further improvements are currently tested in phase 3 clinical renal outcome studies.

Association between Urinary Calcium Excretion and Estimated Glomerular Filtration Rate Decline in Patients with Type 2 Diabetes Mellitus: A Retrospective Single-center Observational Study

Urinary calcium excretion is not known to predict progression of renal dysfunction in patients with type 2 diabetes mellitus. This study aimed to investigate associations between urinary calcium excretion and progression of estimated glomerular filtration rate (eGFR) in type 2 diabetic patients. This study was a retrospective, single-center, observational cohort study. We enrolled a total of 89 patients with type 2 diabetes mellitus and the average follow-up period was 7.2 ± 1.0 years. We divided patients into two groups based on the median of annual decline in the slope of eGFR, then defined the over-median population as the progressed group and under-median population as the non-progressed group. Median of annual decline in the slope of eGFR was &minus;1.1 mL/min/1.73 m²/year. Correlation coefficient analysis showed positive correlation of urinary calcium excretion with eGFR (r = 0.39, p < 0.001). Multivariate logistic analysis showed that baseline eGFR and urinary calcium excretion were independent variables for progression of eGFR decline. Urinary calcium excretion could be a useful metabolic parameter for predicting decline in slope of eGFR in patients with type 2 diabetes mellitus.

Association between dipstick hematuria and decline in estimated glomerular filtration rate among Japanese patients with type 2 diabetes: A prospective cohort study [Diabetes Distress and Care Registry at Tenri (DDCRT 14)]

AIMS

To assess the association between dipstick hematuria and estimated glomerular filtration rate (eGFR) decline in Japanese patients with type 2 diabetes.

METHODS

Longitudinal data were obtained from 3068 Japanese patients with type 2 diabetes. To assess the independent association between dipstick hematuria and eGFR decline, we used Cox proportional hazard model adjusted for potential confounders.

RESULTS

Median follow-up period was 699.7days. Mean age, body mass index (BMI), and HbA1c level were 65.7years, 24.6kg/m², and 7.5% (58.1mmol/mol), respectively. Positive dipstick hematuria was significantly associated with baseline eGFR and severity of albuminuria (p<0.001). The multivariable-adjusted hazard ratio for eGFR decline in patients with dipstick hematuria compared with those without dipstick hematuria was 2.19 [95% confidence interval (CI): 1.22-3.91]; this association remained significant even after the exclusion of patients who did not have diabetic retinopathy (hazard ratio: 2.39; 95% CI: 1.13-5.04).

CONCLUSION

Positive dipstick hematuria was associated with severity of albuminuria and renal function. A significant association was found between dipstick hematuria and increased risk of eGFR decline among patients with type 2 diabetes. Therefore, our results suggest that dipstick hematuria is perhaps indicative of more severe diabetic nephropathy.

Management of type 2 diabetes: the current situation and key opportunities to improve care in the UK

In common with global trends, the number of individuals with type 2 diabetes in the UK is rising, driven largely by obesity. The increasing prevalence of younger individuals with type 2 diabetes is of particular concern because of the accelerated course of diabetes-related complications that is observed in this population. The importance of good glycaemic control in the prevention of microvascular complications of diabetes is widely accepted, and there is a growing body of evidence to support a benefit in the reduction of cardiovascular events in the long term. Despite the importance of maintaining a healthy weight for the prevention of type 2 diabetes, the results from trials of lifestyle intervention strategies to reduce body weight have been disappointing. New glucose-lowering agents offer some promise in this regard, offering an opportunity to combat the dual burden of hyperglycaemia and obesity simultaneously. The timing and appropriate choice of glucose-lowering therapy has never been more complex as a result of rising prevalence of obesity in the young, concomitant obesity in some 90% of adults with type 2 diabetes and an ever-increasing range of therapeutic options. The present review evaluates performance measures specific to weight and glycaemic control in type 2 diabetes in the UK using data from the Quality and Outcomes Framework in England and Wales, and the Scottish Diabetes Survey. Potential barriers to improvement in standards of care for people with type 2 diabetes are considered, including patient factors, clinical inertia and the difficulties in translating therapeutic guidelines into everyday clinical practice.

Diabetic kidney disease: Is there a non-albuminuric phenotype in type 2 diabetic patients?

BACKGROUND

Albuminuria was widely considered as the first clinical sign of diabetic kidney disease (DKD), which is why it has traditionally been used as a screening test for DKD. However, increasing evidence has shown that a significant number of type 2 diabetes mellitus (DM) patients have a decreased glomerular filtration rate (GFR) without significant albuminuria, known as non-albuminuric DKD (NA-DKD). The aim of this study was to determine the prevalence and the demographic and clinical characteristics of patients with NA-DKD.

METHODS

This was a 1-year retrospective study that included 146 type 2 diabetic patients with GFR<75mL/min followed-up in a diabetes outpatient department. Patients were divided into two groups according to their ACR status - NA-DKD and albuminuric DKD (A-DKD).

RESULTS

Of the 146 patients included in the study, 53.4% had A-DKD and 46.6% had NA-DKD. According to the multivariable analysis performed, patients with NA-DKD tended to be older (p=0.021), female (p=0.045) and with a lower GFR (p=0.004) than A-DKD patients. There was no difference between the groups in terms of body mass index, metabolic control of DM, duration of DM diagnosis and prevalence of metabolic syndrome.

CONCLUSIONS

The majority of patients with DKD had albuminuria, but a significant proportion had a non-albuminuric phenotype (46.6% in this population). These patients exhibit distinct clinical features that could have screening, therapeutic and prognosis implications.

Comparison of 2-year clinical outcomes between diabetic versus nondiabetic patients with acute myocardial infarction after 1-month stabilization: Analysis of the prospective registry of DIAMOND (DIabetic acute myocardial infarctiON Disease) in Korea: an observational registry study

This study assessed the 2-year clinical outcomes of patients with diabetes mellitus (DM) after acute myocardial infarction (AMI) in a cohort of the DIAMOND (DIabetic Acute Myocardial infarctiON Disease) registry. Clinical outcomes were compared between 1088 diabetic AMI patients in the DIAMOND registry after stabilization of MI and 1088 nondiabetic AMI patients from the KORMI (Korean AMI) registry after 1 : 1 propensity score matching using traditional cardiovascular risk factors. Stabilized patients were defined as patients who did not have any clinical events within 1 month after AMI. Primary outcomes were the 2-year rate of major adverse cardiac events (MACEs), a composite of all-cause death, recurrent MI (re-MI), and target vessel revascularization (TVR). Matched comparisons revealed that diabetic patients exhibited significantly lower left ventricular ejection fraction (LVEF) and estimated glomerular filtration rate and smaller stent size. Diabetic patients exhibited significantly higher 2-year rates of MACE (8.0% vs 3.7%), all-cause death (3.9% vs 1.4%), re-MI (2.8% vs 1.2%), and TVR (3.5% vs 1.3%) than nondiabetic patients (all P < 0.01), and higher cumulative rates in Kaplan-Meier analyses of MACE, all-cause death, and TVR (all P < 0.05). A multivariate Cox regression analysis revealed that chronic kidney disease, LVEF < 35%, and long stent were independent predictors of MACE, and large stent diameter and the use of drug-eluting stents were protective factors against MACE. The 2-year MACE rate beyond 1 month after AMI was significantly higher in DM patients than non-DM patients, and this rate was associated with higher comorbidities, coronary lesions, and procedural characteristics in DM.

Factors affecting the progression of renal dysfunction and the importance of salt restriction in patients with type 2 diabetic kidney disease

BACKGROUND

Type 2 diabetic kidney disease (DKD) is the most common cause of end-stage renal failure, and the prevention of its progression has been a topic of discussion.

METHODS

Sixty type 2 DKD patients were retrospectively evaluated for 1 year. Factors independently affecting the annual Ccr decline were examined by multivariable linear regression analysis. Patients were further divided into 2 groups based on their degree of renal function, and between-group differences at study initiation were evaluated.

RESULTS

Ccr values were 21.0 ± 11.8 mL/min/1.73 m(2) at study initiation, and 15.7 ± 10.9 mL/min/1.73 m(2) after 1 year of observation. The multivariable linear regression analysis indicated salt intake (standardized coefficient: -0.34, P = 0.010) and urinary protein excretion (standardized coefficient: -0.33, P = 0.011) to be factors independently affecting the annual Ccr decline. Although decliners (-9.8 ± 4.7 mL/min/1.73 m(2)/year) had a significantly higher salt intake than non-decliners (-1.1 ± 3.8 mL/min/1.73 m(2)/year) at study initiation, this difference disappeared at the end of the study as a result of intensive dietary education. In 21 decliners with an additional year of follow-up, the annual Ccr decline significantly improved from -10.1 ± 5.3 to -5.3 ± 7.4 mL/min/1.73 m(2)/year (P = 0.02).

CONCLUSION

Salt intake and urinary protein excretion were associated with annual Ccr decline in type 2 DKD patients. Furthermore, dietary education covering salt intake may have positively affected the change in Ccr.

Incidence of renal replacement therapy for diabetic nephropathy in the Netherlands: Dutch diabetes estimates (DUDE)-3

OBJECTIVES

Describe the incidence, prevalence and survival of patients needing renal replacement therapy (RRT) for end-stage renal disease (ESRD) due to diabetes mellitus (DM)-related glomerulosclerosis or nephropathy (diabetic nephropathy, DN) in the Netherlands.

DESIGN

Using the national registry for RRT (RENINE-registry), data of all Dutch individuals initiating RRT for ESRD and having DN as primary diagnosis in the period 2000-2012 were obtained.

SETTING

Observational study in the Netherlands.

PATIENTS

Patients with ESRD needing RRT for DN.

OUTCOME MEASUREMENTS

Age and gender adjusted incidence and prevalence of RRT for DN in the period 2000-2012. In addition, trends in time and patient's survival were examined.

RESULTS

The prevalence of DM in the general population increased from approximately 466 000 in 2000 to 815 000 in 2011. The number of individuals who started RRT with DN as primary diagnosis was 17.4 per million population (pmp) in 2000 and 19.1 pmp in 2012, with an annual percentage change (APC) of 0.8% (95% CI -0.4 to 2.0). For RRT due to type 1 DN, the incidence decreased from 7.3 to 3.5 pmp (APC -4.8%, 95% CI -6.5 to -3.1) while it increased for type 2 DN from 10.1 to 15.6 pmp (APC 3.1%, 95% CI 1.3 to 4.8). After 2009, the prevalence of RRT for DN remained stable (APC 1.0%, 95% CI -0.4 to 2.5). Compared to the period 2000-2004, patients initiating RRT and dialysis in 2005-2009 had better survival, HRs 0.8 (95% CI 0.7 to 0.8) and 0.8 (95% CI 0.7 to 0.9), respectively, while survival after kidney transplantation remained stable, HR 0.8, 95% CI 0.5 to 1.1).

CONCLUSIONS

Over the last decade, the incidence of RRT for DN was stable, with a decrease in RRT due to type 1 DN and an increase due to type 2 DN, while survival increased.

Vitamin B and its derivatives for diabetic kidney disease

BACKGROUND

Diabetes is a leading cause of end-stage kidney disease (ESKD) mainly due to development and progression of diabetic kidney disease (DKD). In absence of definitive treatments of DKD, small studies showed that vitamin B may help in delaying progression of DKD by inhibiting vascular inflammation and endothelial cell damage. Hence, it could be beneficial as a treatment option for DKD.

OBJECTIVES

To assess the benefits and harms of vitamin B and its derivatives in patients with DKD.

SEARCH METHODS

We searched the Cochrane Renal Group's Specialised Register to 29 October 2012 through contact with the Trials' Search Co-ordinator using search terms relevant to this review.

SELECTION CRITERIA

We included randomised controlled trials comparing vitamin B or its derivatives, or both with placebo, no treatment or active treatment in patients with DKD. We excluded studies comparing vitamin B or its derivatives, or both among patients with pre-existing ESKD.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study eligibility, risk of bias and extracted data. Results were reported as risk ratio (RR) or risk differences (RD) with 95% confidence intervals (CI) for dichotomous outcomes and mean difference (MD) with 95% CI for continuous outcomes. Statistical analyses were performed using the random-effects model.

MAIN RESULTS

Nine studies compared 1354 participants randomised to either vitamin B or its derivatives with placebo or active control were identified. A total of 1102 participants were randomised to single vitamin B derivatives, placebo or active control in eight studies, and 252 participants randomised to multiple vitamin B derivatives or placebo. Monotherapy included different dose of pyridoxamine (four studies), benfotiamine (1), folic acid (1), thiamine (1), and vitamin B12 (1) while combination therapy included folic acid, vitamin B6, and vitamin B12 in one study. Treatment duration ranged from two to 36 months. Selection bias was unclear in three studies and low in the remaining six studies. Two studies reported blinding of patient, caregiver and observer and were at low risk of performance and detection bias, two studies were at high risk bias, and five studies were unclear. Attrition bias was high in one study, unclear in one study and low in seven studies. Reporting bias was high in one study, unclear in one study, and low in the remaining seven studies. Four studies funded by pharmaceutical companies were judged to be at high risk bias, three were at low risk of bias, and two were unclear.Only a single study reported a reduction in albuminuria with thiamine compared to placebo, while second study reported reduction in glomerular filtration rate (GFR) following use of combination therapy. No significant difference in the risk of all-cause mortality with pyridoxamine or combination therapy was reported. None of the vitamin B derivatives used either alone or in combination improved kidney function: increased in creatinine clearance, improved the GFR; neither were effective in controlling blood pressure significantly compared to placebo or active control. One study reported a significant median reduction in urinary albumin excretion with thiamine treatment compared to placebo. No significant difference was found between vitamin B combination therapy and control group for serious adverse events, or one or more adverse event per patient. Vitamin B therapy was reported to well-tolerated with mild side effects in studies with treatment duration of more than six months. Studies of less than six months duration did not explicitly report adverse events; they reported that the drugs were well-tolerated without any serious drug related adverse events. None of the included studies reported cardiovascular death, progression from macroalbuminuria to ESKD, progression from microalbuminuria to macroalbuminuria, regression from microalbuminuria to normoalbuminuria, doubling of SCr, and quality of life. We were not able to perform subgroup or sensitivity analyses or assess publication bias due to insufficient data.

AUTHORS' CONCLUSIONS

There is an absence of evidence to recommend the use of vitamin B therapy alone or combination for delaying progression of DKD. Thiamine was found to be beneficial for reduction in albuminuria in a single study; however, there was lack of any improvement in kidney function or blood pressure following the use of vitamin B preparations used alone or in combination. These findings require further confirmation given the limitations of the small number and poor quality of the available studies.

The eGFR-C study: accuracy of glomerular filtration rate (GFR) estimation using creatinine and cystatin C and albuminuria for monitoring disease progression in patients with stage 3 chronic kidney disease--prospective longitudinal study in a multiethnic population

BACKGROUND

Uncertainty exists regarding the optimal method to estimate glomerular filtration rate (GFR) for disease detection and monitoring. Widely used GFR estimates have not been validated in British ethnic minority populations.

METHODS/DESIGN

Iohexol measured GFR will be the reference against which each estimating equation will be compared. The estimating equations will be based upon serum creatinine and/or cystatin C. The eGFR-C study has 5 components: 1) A prospective longitudinal cohort study of 1300 adults with stage 3 chronic kidney disease followed for 3 years with reference (measured) GFR and test (estimated GFR [eGFR] and urinary albumin-to-creatinine ratio) measurements at baseline and 3 years. Test measurements will also be undertaken every 6 months. The study population will include a representative sample of South-Asians and African-Caribbeans. People with diabetes and proteinuria (ACR ≥30 mg/mmol) will comprise 20-30% of the study cohort.2) A sub-study of patterns of disease progression of 375 people (125 each of Caucasian, Asian and African-Caribbean origin; in each case containing subjects at high and low risk of renal progression). Additional reference GFR measurements will be undertaken after 1 and 2 years to enable a model of disease progression and error to be built.3) A biological variability study to establish reference change values for reference and test measures.4) A modelling study of the performance of monitoring strategies on detecting progression, utilising estimates of accuracy, patterns of disease progression and estimates of measurement error from studies 1), 2) and 3).5) A comprehensive cost database for each diagnostic approach will be developed to enable cost-effectiveness modelling of the optimal strategy.The performance of the estimating equations will be evaluated by assessing bias, precision and accuracy. Data will be modelled as a linear function of time utilising all available (maximum 7) time points compared with the difference between baseline and final reference values. The percentage of participants demonstrating large error with the respective estimating equations will be compared. Predictive value of GFR estimates and albumin-to-creatinine ratio will be compared amongst subjects that do or do not show progressive kidney function decline.

DISCUSSION

The eGFR-C study will provide evidence to inform the optimal GFR estimate to be used in clinical practice.

TRIAL REGISTRATION

ISRCTN42955626.

Predictors of estimated GFR decline in patients with type 2 diabetes and preserved kidney function

BACKGROUND AND OBJECTIVES

This study examined predictors of the annual decline in estimated GFR (eGFR) in patients with type 2 diabetes and preserved kidney function.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In a prospective, observational cohort study, 1682 individuals with type 2 diabetes and baseline eGFR ≥60 ml/min per 1.73 m(2) (as estimated by the Chronic Kidney Disease Epidemiology Collaboration equation) were followed for 10 years. Linear regression was used to estimate participants' changes in eGFR over time.

RESULTS

During follow-up, 263 (15.6%) individuals had a rapid eGFR decline defined as >4.0% per year. Average eGFR decline was -5.8 ± 3 and -0.6 ± 2 ml/min per 1.73 m(2) per year in rapid decliners and nondecliners, respectively. Compared with normotensive, normoalbuminuric patients (-0.2 ± 0.2 ml/min per 1.73 m(2) per year), those with hypertension (-1.0 ± 0.1 ml/min per 1.73 m(2) per year), hemoglobin A(1c)≥7% (-1.0 ± 0.1 ml/min per 1.73 m(2) per year), longer diabetes duration (-1.0 ± 0.1 ml/min per 1.73 m(2) per year), obesity (-1.2 ± 0.1 ml/min per 1.73 m(2) per year), insulin treatment (-1.5 ± 0.1 ml/min per 1.73 m(2) per year), microalbuminuria (-1.3 ± 0.2 ml/min per 1.73 m(2) per year), or macroalbuminuria (-2.7 ± 0.4 ml/min per 1.73 m(2) per year) had significantly faster age-adjusted annual eGFR declines. Multivariable linear regression analyses revealed that albuminuria (P<0.001) was the strongest predictor of annual eGFR decline. Other independent predictors of annual eGFR decline were older age, hypertension, insulin treatment, and lower baseline eGFR.

CONCLUSIONS

Annual eGFR decline is predicted by multiple modifiable risk factors in patients with type 2 diabetes and preserved kidney function.

Rate of change in kidney function and the risk of death: the case for incorporating the rate of kidney function decline into the CKD staging system

Chronic kidney disease (CKD) is associated with increased risk of death. A wave of recent studies used longitudinal data to examine the effect of the rate of decline of kidney function on the risk of death. The results from these studies show that there is an independent and graded association between the rate of kidney function decline and the risk of death. There is a need to incorporate the rate of decline in the definition of CKD. This redefinition of CKD will transform a static definition into a dynamic one that more accurately describes the disease state in an individual patient.

Proteinuria in type 2 diabetic patients with renal impairment: the changing face of diabetic nephropathy

Type 2 diabetic nephropathy (type 2 DN) patients traditionally develop significant proteinuria prior to the development of renal impairment. However, this clinical paradigm, based on observations prior to the widespread usage of angiotensin-converting enzyme inhibitors (ACEi) or angiotensin receptor blockers (ARB), has recently been questioned. 2,303 patients enrolled in the Sulodexide Overt Nephropathy Study (OVERT) were analyzed. Prior therapy with ACEi and/or ARB at the time of screening was recorded in 951 patients. 22% of patients had significant renal impairment with a PCR at screening of <500 mg/g. Therapy with ACEi and/or ARB at the time of screening was recorded in 94%, where prior medication data was available. In patients with type 2 DN and advanced renal impairment, levels of proteinuria below that which traditionally defines overt diabetic nephropathy, are found in more than one fifth of patients. We suggest that the high prevalence of ACEi and ARB usage in patients with type 2 DN may be effecting the traditional clinical paradigm of type 2 DN.

A molecular signature of proteinuria in glomerulonephritis

Proteinuria is the most important predictor of outcome in glomerulonephritis and experimental data suggest that the tubular cell response to proteinuria is an important determinant of progressive fibrosis in the kidney. However, it is unclear whether proteinuria is a marker of disease severity or has a direct effect on tubular cells in the kidneys of patients with glomerulonephritis. Accordingly we studied an in vitro model of proteinuria, and identified 231 “albumin-regulated genes” differentially expressed by primary human kidney tubular epithelial cells exposed to albumin. We translated these findings to human disease by studying mRNA levels of these genes in the tubulo-interstitial compartment of kidney biopsies from patients with IgA nephropathy using microarrays. Biopsies from patients with IgAN (n = 25) could be distinguished from those of control subjects (n = 6) based solely upon the expression of these 231 “albumin-regulated genes.” The expression of an 11-transcript subset related to the degree of proteinuria, and this 11-mRNA subset was also sufficient to distinguish biopsies of subjects with IgAN from control biopsies. We tested if these findings could be extrapolated to other proteinuric diseases beyond IgAN and found that all forms of primary glomerulonephritis (n = 33) can be distinguished from controls (n = 21) based solely on the expression levels of these 11 genes derived from our in vitro proteinuria model. Pathway analysis suggests common regulatory elements shared by these 11 transcripts. In conclusion, we have identified an albumin-regulated 11-gene signature shared between all forms of primary glomerulonephritis. Our findings support the hypothesis that albuminuria may directly promote injury in the tubulo-interstitial compartment of the kidney in patients with glomerulonephritis.

Human glomerular endothelium: interplay among glucose, free fatty acids, angiotensin II, and oxidative stress

Glomerular endothelial cells (GEC) are strategically situated within the capillary loop and adjacent to the glomerular mesangium. GEC serve as targets of metabolic, biochemical, and hemodynamic signals that regulate the glomerular microcirculation. Unequivocally, hyperglycemia, hypertension, and the local renin-angiotensin system partake in the initiation and progression of diabetic nephropathy (DN). Whether free fatty acids (FFA) and reactive oxygen species (ROS) that have been associated with the endothelial dysfunction of diabetic macrovascular disease also contribute to DN is not known. Since endothelial cells from different organs and from different species may display different phenotypes, we employed human GEC to investigate the effect of high glucose (22.5 mmol/l), FFA (800 micromol/l), and angiotensin II (ANG II; 10(-7) mol/l) on the genesis of ROS and their effects on endothelial nitric oxide synthase (eNOS), cyclooxygenase-2 (COX-2), and the synthesis of prostaglandins (PGs). We demonstrated that high glucose but not high FFA increased the expression of a dysfunctional eNOS as well as increased ROS from NADPH oxidase (100%) and likely from uncoupled eNOS. ANG II also induced ROS from NADPH oxidase. High glucose and ANG II upregulated (100%) COX-2 via ROS and significantly increased the synthesis of prostacyclin (PGI(2)) by 300%. In contrast, FFA did not upregulate COX-2 but increased PGI(2) (500%). These novel studies are the first in human GEC that characterize the differential role of FFA, hyperglycemia, and ANG II on the genesis of ROS, COX-2, and PGs and their interplay in the early stages of hyperglcyemia.

Diabetic nephropathy

Diabetic nephropathy is the leading cause of chronic renal disease and a major cause of cardiovascular mortality. Diabetic nephropathy has been categorized into stages: microalbuminuria and macroalbuminuria. The cut-off values of micro- and macroalbuminuria are arbitrary and their values have been questioned. Subjects in the upper-normal range of albuminuria seem to be at high risk of progression to micro- or macroalbuminuria and they also had a higher blood pressure than normoalbuminuric subjects in the lower normoalbuminuria range. Diabetic nephropathy screening is made by measuring albumin in spot urine. If abnormal, it should be confirmed in two out three samples collected in a three to six-months interval. Additionally, it is recommended that glomerular filtration rate be routinely estimated for appropriate screening of nephropathy, because some patients present a decreased glomerular filtration rate when urine albumin values are in the normal range. The two main risk factors for diabetic nephropathy are hyperglycemia and arterial hypertension, but the genetic susceptibility in both type 1 and type 2 diabetes is of great importance. Other risk factors are smoking, dyslipidemia, proteinuria, glomerular hyperfiltration and dietary factors. Nephropathy is pathologically characterized in individuals with type 1 diabetes by thickening of glomerular and tubular basal membranes, with progressive mesangial expansion (diffuse or nodular) leading to progressive reduction of glomerular filtration surface. Concurrent interstitial morphological alterations and hyalinization of afferent and efferent glomerular arterioles also occur. Podocytes abnormalities also appear to be involved in the glomerulosclerosis process. In patients with type 2 diabetes, renal lesions are heterogeneous and more complex than in individuals with type 1 diabetes. Treatment of diabetic nephropathy is based on a multiple risk factor approach, and the goal is retarding the development or progression of the disease and to decrease the subject's increased risk of cardiovascular disease. Achieving the best metabolic control, treating hypertension (<130/80 mmHg) and dyslipidemia (LDL cholesterol <100 mg/dl), using drugs that block the renin-angiotensin-aldosterone system, are effective strategies for preventing the development of microalbuminuria, delaying the progression to more advanced stages of nephropathy and reducing cardiovascular mortality in patients with diabetes.

Higher levels of urinary albumin excretion within the normal range predict faster decline in glomerular filtration rate in diabetic patients

OBJECTIVE To assess the relationship between albuminuria, including elevation within the normal range, and decline in glomerular filtration rate (GFR) in diabetic patients. RESEARCH DESIGN AND METHODS A total of 5,449 Japanese diabetic patients were categorized according to sex and urinary albumin-to-creatinine ratio (ACR; <5, 5-9, 10-29, 30-99, 100-299, 300-999, 1,000-2,999, and > or =3,000 mg/g) and followed for at least 5 years. The rate of change in estimated GFR (eGFR) adjusted for age and baseline eGFR was compared among ACR categories. RESULTS A higher baseline ACR predicted a faster decline in eGFR for both sexes. Even within the normal range (<30 mg/g), ACR > or =10 mg/g in women and > or =5 mg/g in men was associated with a significantly greater rate of decline in eGFR relative to subjects with ACR <5 mg/g. CONCLUSIONS Elevated ACR, even within the normal range, is associated with a faster decline in eGFR in diabetic patients.

The natural course of microalbuminuria among African Americans with type 2 diabetes: a 3-year study

BACKGROUND

The natural course of microalbuminuria in African Americans (AA) with type 2 diabetes is not well established.

METHOD

Longitudinal analysis of 186 African Americans with type 2 diabetes enrolled in Project Sugar, a randomized controlled trial of primary care-based interventions to improve diabetes control.

RESULTS

Mean age was 59.4 years and 85% were female. Mean estimated glomerular filtration rate and urinary albumin-to-creatinine ratio were 75.90 mL/min/1.73 m(2) and 1.62, respectively. Thirty-nine patients had macroalbuminuria and significantly higher systolic blood pressure compared with those with microalbuminuria (P=.01). Sixty patients had microalbuminuria, 19 progressed to macroalbuminuria, and none regressed. Progression was associated significantly with systolic blood pressure >or=115 mm Hg and requirement for blood pressure medication in the univariate model. In the multivariate model, the degree of albumin-to-creatinine ratio (odds ratio 35.51, 95% confidence interval, 2.21-571.65) and need for blood pressure medication (odds ratio 8.96, 95% confidence interval, 1.35-59.70) were independently associated with progression. No association was observed with the use of specific antihypertensive agent.

CONCLUSION

This study suggests that African Americans with type 2 diabetes and microalbuminuria experience irreversible disease that not infrequently progresses to overt proteinuria. The degree of microalbuminuria and blood pressure are key determinants in this process and should be primary targets in treating this population regardless of the antihypertensive class used.

MTHFR gene polymorphism is susceptible to diabetic retinopathy but not to diabetic nephropathy in Japanese type 2 diabetic patients

AIMS

Previously, we have proposed that methylenetetrahydrofolate reductase (MTHFR) gene polymorphism (C677T) could be a risk factor for diabetic retinopathy. To support our suggestion, we examined in detail the association of MTHFR polymorphism with diabetic retinopathy and nephropathy in Japanese type 2 diabetic patients.

METHODS

Subjects (n=190) were free of cardiovascular diseases and were not on hemodialysis. Retinopathy was assessed according to fundamental differentiation; nephropathy was determined according to urinary albumin level; and MTHFR genotype was determined by polymerase chain reaction-restriction fragment length polymorphism. We also analyzed how hyperglycemia affected these three conditions in 131 patients with glycosylated hemoglobin > or =6.5% and fasting blood sugar > or =110 mg/dl.

RESULTS

The frequency of 677T/677T homozygous subjects with retinopathy was higher than the frequencies of the other two genotypes, and a significant difference was observed in the distribution of the genotypes (677C/677C, 41.9%; 677C/677T, 31.1%; 677T/677T, 61.5%; P<.05). The susceptibility of 677T/677T homozygote to retinopathy approached significance [odds ratio (OR)=2.17; 95% confidence interval (95% CI)=0.87-5.42]. However, in the population with hyperglycemia, the 677T/677T homozygote modified the risk for retinopathy (OR=4.30; 95% CI=1.42-13.1), especially the risk for nonproliferative retinopathy. In contrast, the 677T/677T homozygote did not affect the risk for nephropathy (OR=1.17; 95% CI=0.45-3.05), even in subjects with hyperglycemia (OR=1.50; 95% CI=0.50-4.48).

CONCLUSIONS

Our results are highly suggestive of an important role for MTHFR genotype in susceptibility to retinopathy under hyperglycemia, but not to nephropathy. Preventive therapies based on MTHFR polymorphism could delay the onset of retinopathy in type 2 diabetic patients.

Overutilization of central venous catheters in incident hemodialysis patients: reasons and potential resolution strategies

Even after adjusting for comorbidities, the outcomes in hemodialysis (HD) patients using a central venous catheter (CVC) as dialysis access are worse than in those with a permanent vascular access. In spite of this, nationwide data suggest that only about 25% of incident HD patients initiate dialysis with an arteriovenous fistula. We conducted a retrospective study to identify reasons and resolution strategies for CVC use in patients who initiated HD at an academic medical center with a well-established chronic kidney disease (CKD) clinic and a dedicated vascular surgeon. Estimated glomerular filtration rate (eGFR) loss over time to record progression of patients to HD was also examined. The charts of 170 consecutive patients were reviewed. Ninety-two percent were found to initiate HD using a CVC. Three factors explained 93% of all CVC in our cohort: absence of adequate predialysis care (45%), acute illness with failure to recover from an episode of acute renal failure (31%), and patient's failure to adhere to scheduled clinic or surgical appointments (17%). In addition, analyses of eGFR suggest that the velocity of GFR loss rather than a defined degree of renal function might be a better trigger for vascular access referral. We conclude that early referral, a close follow up of CKD patients who initiate dialysis due to acute illness, and patient education may have a positive impact to counteract overutilization of CVCs for dialysis. The rate in eGFR decline might also be used to calculate the referral time adequate for fistula creation.

Improving outcomes in diabetes and chronic kidney disease: the basis for Canadian guidelines

The prevalence of diabetes is on the rise in Canada, and there has been a corresponding increase in the rate of micro- and macrovascular complications. Among the worst of these is chronic kidney disease (CKD). It may be diagnosed either through the detection of persistent albuminuria or an estimated glomerular filtration rate that is persistently less than 60 mL/min/1.73 m2. Patients with diabetes and CKD have a lower quality of life and higher health care costs, and face the prospect of end-stage renal disease requiring dialysis. More importantly, this group has an extremely elevated cardiovascular risk and correspondingly reduced survival. Research over several decades has led to two important conclusions. First, progressive worsening of kidney disease is not inevitable in people with diabetes; it can be slowed or even stopped. Second, the elevated cardiovascular risk in this population can be significantly reduced through an aggressive approach to cardiovascular risk factor reduction. These conclusions have prompted Canadian guideline groups, such as the Canadian Diabetes Association and the Canadian Hypertension Education Program, to release clinical practice guidelines that address the management of people with diabetes and CKD. In the present article, the studies that have influenced these Canadian guidelines are examined, and areas in which further research is still required are identified.

Are glomerular volume differences between type 1 and type 2 diabetic patients pathologically significant?

The observation that patients with type 2 diabetes tend to have larger glomeruli than patients with type 1 diabetes was first made more than 10 years ago. It has also been noted that type 2 diabetic patients with nephropathy often have more heterogeneous renal function and structure than type 1 patients. However, whether these observations are linked or have any bearing on the progression of nephropathy in the two types of diabetes remains uncertain. Here we put forward several hypotheses as to why glomerular volume in type 1 differs from that in type 2 diabetes. We suggest that although type 1 and type 2 diabetic patients appear to progress through similar stages of diabetic nephropathy, the route they take may differ. Differences in the way in which the glomeruli respond to the diabetic milieu may enable some type 2 diabetic patients to preserve their filtration surface in the face of an expanding mesangium.

Nefropatia diabética e doença cardíaca

Pacientes em diferentes estágios de nefropatia diabética (ND) apresentam freqüentemente comprometimento cardíaco expresso por isquemia miocárdica e/ou cardiomiopatia diabética. Estas alterações já estão presentes em estágios iniciais da ND e provavelmente mesmo antes de a excreção urinária de albumina (EUA) atingir níveis tradicionalmente diagnósticos de microalbuminúria. As alterações cardíacas são responsáveis por uma proporção significativa de mortes nos pacientes com ND e podem ser reduzidas através de intervenção nos múltiplos fatores de risco cardiovascular encontrados nesses pacientes. A avaliação de doença cardíaca deve idealmente ser realizada em todos os pacientes com qualquer grau de ND através de métodos específicos para detectar isquemia e disfunção miocárdica, além do emprego rotineiro da monitorização ambulatorial da pressão arterial em 24 h. Em pacientes com aterosclerose avançada também devem ser avaliadas outras artérias (carótidas, aorta, renais). O tratamento rigoroso da hipertensão arterial, o uso de fármacos cardioprotetores, o tratamento da dislipidemia e da anemia, assim como o emprego de medicamentos anti-plaquetários, poderão reduzir a elevada mortalidade cardiovascular na ND.

Blood pressure lowering for the prevention and treatment of diabetic kidney disease

The current pandemic of diabetes mellitus will inevitably be followed by an epidemic of chronic kidney disease. It is anticipated that 25-40% of patients with type 1 diabetes and 5-40% of patients with type 2 diabetes will ultimately develop diabetic kidney disease. The control of blood pressure represents a key component for the prevention and management of diabetic nephropathy. There is a strong epidemiological connection between hypertension in diabetes and adverse outcomes in diabetes. Hypertension is closely linked to insulin resistance as part of the 'metabolic syndrome'. Diabetic nephropathy may lead to hypertension through direct actions on renal sodium handling, vascular compliance and vasomotor function. Recent clinical trials also support the utility of blood pressure reduction in the prevention of diabetic kidney disease. In patients with normoalbuminuria, transition to microalbuminuria can be prevented by blood pressure reduction. This action appears to be significant regardless of whether patients have elevated blood pressure or not. The efficacy of ACE inhibition appears to be greater than that achieved by other agents with a similar degree of blood pressure reduction; although large observational studies suggest the risk of microalbuminuria may be reduced by blood pressure reduction, regardless of modality. In patients with established microalbuminuria, ACE inhibitors and angiotensin receptor antagonists (angiotensin receptor blockers [ARBs]) consistently reduce the risk of progression from microalbuminuria to macroalbuminuria, over and above their antihypertensive actions. The clinical utility of combining these strategies remains to be established. In patients with overt nephropathy, blood pressure reduction is associated with reduced urinary albumin excretion and, subsequently, a reduced risk of renal impairment or end stage renal disease. In addition to actions on systemic blood pressure, it is now clear that ACE inhibitors and ARBs also reduce proteinuria in patients with diabetes. This anti-proteinuric activity is distinct from other antihypertensive agents and diuretics. Although there is a clear physiological rationale for blockade of the renin angiotensin system, which is strongly supported by clinical studies, to achieve the optimal lowering of blood pressure, particularly in the setting of established diabetic renal disease, a number of different antihypertensive agents will always be needed. In the end, the choice of agents should be individualised to achieve the maximal tolerated reduction in blood pressure and albuminuria. Ultimately, no matter how it is achieved, so long as it is achieved, renal risk can be reduced by agents that lower blood pressure and albuminuria.

Macrophage accumulation in human progressive diabetic nephropathy

BACKGROUND

Diabetic nephropathy is a major global health problem. Progression to renal failure is common; however, the mechanisms are unknown. Experimental models suggest a role for macrophages. Therefore, macrophage accumulation and its relationship to the subsequent clinical course were studied.

METHODS

A retrospective study of baseline histology and the subsequent clinical course over at least 5 years involving 20 consecutive patients with a histological and clinical diagnosis of diabetic nephropathy was performed. The relationship between macrophage accumulation in renal biopsy tissue (KP-1/anti-CD68+ cells), baseline measures of known predictors of progression (proteinuria, tubulointerstitial damage, myofibroblast accumulation) and progression over 5 years (plot of reciprocal of serum creatinine) was quantified.

RESULTS

Accumulation of macrophages was apparent in the glomeruli (2.8 + 0.7/gcs vs 1.0 + 0.2 for normals, P = not significant) and interstitium (296.9 + 63.3/mm(2) vs 19.0 + 1.3/mm(2) for normals, P = 0.002) of patients with diabetic nephropathy. Glomerular macrophage number correlated with baseline serum creatinine (r = 0.548, P = 0.012) but not with progression of renal failure as glomerular macrophages were prevalent in early, but not advanced diabetic nephropathy. Interstitial macrophage accumulation correlated strongly with serum creatinine (r = 0.649, P = 0.002), proteinuria (r = 0.779, P < 0.0001), interstitial fibrosis (r = 0.774, P < 0.0001) and inversely with the slope of 1/serum creatinine (r = -0.531, P = 0.023).

CONCLUSION

Macrophages accumulate within glomeruli and the interstitium in diabetic nephropathy and the intensity of the interstitial infiltrate is proportional to the rate of subsequent decline in renal function. These human data support animal studies that suggest a pathogenic role for the macrophage in diabetic nephropathy.

Glomerular filtration rate changes in normoalbuminuric and microalbuminuric Type 2 diabetic patients and normal individuals A 10-year follow-up

AIM

To analyze the changes in the glomerular filtration rate (GFR) in a cohort of normoalbuminuric Type 2 diabetic (DM 2) patients and nondiabetic individuals.

METHODS

Sixty-five normoalbuminuric DM 2 patients [urinary albumin excretion rate (UAER) <20 microg/min] and 44 nondiabetic individuals recruited at baseline were followed for a mean period of 10 +/- 1 years. In addition to conventional clinical and metabolic variables, GFR ((51)Cr-EDTA technique) and UAER (immunoturbidimetric method) measurements were performed at baseline and at follow-up. We also evaluated the presence of diabetic retinopathy, hypertension, and cardiovascular disease. Multiple linear regression was performed to assess variables independently associated with GFR evolution in patients with Type 2 diabetes.

RESULTS

Fifty DM 2 patients and 32 nondiabetic individuals were included in the follow-up evaluation. Fourteen out of the 50 patients with Type 2 diabetes developed microalbuminuria. They presented a faster GFR decline (-0.39+/-0.24 ml/min/month; ANOVA, P=.0013) than did persistently normoalbuminuric (-0.16+/-0.16 ml/min/month) and nondiabetic individuals (-0.13+/-0.14 ml/min/month). Multiple linear regression analysis disclosed baseline fasting plasma glucose (FPG) along with the development of microalbuminuria as factors significantly related to a higher GFR decline.

CONCLUSIONS

Persistently normoalbuminuric patients and normal individuals presented a similar degree of GFR reduction related to the aging process. The slope was significantly enhanced in patients who developed microalbuminuria and was influenced by worse baseline glucose control.

Antihypertensive agents for preventing diabetic kidney disease

BACKGROUND

Twenty to sixty percent of diabetic patients are affected by hypertension and antihypertensive agents are used to treat this condition. These agents are also used to prevent the onset of kidney disease both in normotensive and hypertensive diabetics.

OBJECTIVES

To evaluate the comparative effects of antihypertensive agents in patients with diabetes and normoalbuminuria.

SEARCH STRATEGY

MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, conference proceedings, and contact with investigators were used to identify relevant trials.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing any antihypertensive agent with placebo or another agent in hypertensive or normotensive patients with diabetes and no kidney disease (albumin excretion rate < 30 mg/d) were included.

DATA COLLECTION AND ANALYSIS

Two investigators independently extracted data on renal outcomes and other patient relevant outcomes (all-cause mortality, serious cardiovascular events), and assessed quality of trials. Analysis was by a random effects model and results expressed as relative risk (RR) and 95% confidence intervals (CI).

MAIN RESULTS

Sixteen trials (7603 patients) were identified, six of angiotensin converting enzyme inhibitors (ACEi) versus placebo, six of ACEi versus calcium channel blockers (CCBs), one of ACEi versus CCBs or combined ACEi and CCBs and three of ACEi versus other agents. Compared to placebo, ACEi significantly reduced the development of microalbuminuria (six trials, 3840 patients: RR 0.60, 95% CI 0.43 to 0.84) but not doubling of creatinine (three trials, 2683 patients: RR 0.81, 95% CI 0.24 to 2.71) or all-cause mortality (four trials, 3284 patients: RR 0.81, 95% CI 0.64 to 1.03). Compared to CCBs, ACEi significantly reduced progression to microalbuminuria (four trials, 1210 patients: RR 0.58, 95% CI 0.40 to 0.84).

AUTHORS' CONCLUSIONS

A significant reduction in the risk of developing microalbuminuria in normoalbuminuric patients with diabetes has been demonstrated for ACEi only. It appears that the effect of ACEi is independent of baseline blood pressure, renal function and type of diabetes, but data is too sparse to be confident that these are not important effect modifiers and an individual patient data meta-analysis is required.

The role of statins in chronic kidney disease

Chronic kidney disease is associated with cardiovascular event rates that are at least as high as in patients with established atherosclerotic cardiovascular disease or in those with diabetes mellitus. Chronic kidney disease is therefore considered a cardiovascular disease risk equivalent. Treatment of dyslipidemia, which is very common in this population and reflects the pattern seen in the metabolic syndrome, reduces cardiovascular events in patients with chronic kidney disease. Thus, patients with chronic kidney disease should be evaluated and treated for dyslipidemia. Dyslipidemia is a risk factor for the development of impaired kidney function. Dyslipidemia is also associated with progressive renal disease in subjects with no overt renal disease, as well as those with diabetic and nondiabetic kidney disease. Although definitive randomized controlled trials are lacking, the collective evidence suggests that treatment of dyslipidemia is associated with less decline in renal function. The use of potent statins in high doses can lead to transient proteinuria via impairment of proximal tubular receptor--mediated endocytosis, in a dose-dependent manner. Over the long term, however, the use of statins results in a reduction in proteinuria and in the rate of decline of renal function. Several large definitive trials that are currently underway to examine the safety and efficacy of statins in cardiovascular and renal protection should provide more definitive answers on the role of these drugs in this very high risk population.

Progression of kidney disease in type 2 diabetes - beyond blood pressure control: an observational study

BACKGROUND

The risk factors for progression of chronic kidney disease (CKD) in type 2 diabetes mellitus (DM) have not been fully elucidated. Although uncontrolled blood pressure (BP) is known to be deleterious, other factors may become more important once BP is treated.

METHODS

All patients seen in the outpatient clinics of our hospital between January 1993 and September 2002 with type 2 DM and clinical evidence of CKD were evaluated. Progression of kidney disease was evaluated by rate of decline of glomerular filtration rate (GFR) as estimated from the simplified MDRD formula. Variables associated with progression in univariate analyses were examined by multivariate analysis to determine the factors independently associated with kidney disease progression.

RESULTS

343 patients (mean age 69 years; all male; 77% Caucasian) were studied. Mean BP, glycated hemoglobin, and serum cholesterol during the study period were 138/72 mmHg, 8.1%, and 4.8 mmol/L, respectively. Mean decline of GFR was 4.5 ml min-1 1.73 m2-1 yr-1 (range -14 to +32). Low initial serum albumin (p < 0.001), black race (p < 0.001), and degree of proteinuria (p = 0.002), but not blood pressure, glycated hemoglobin, or serum cholesterol, were independently associated with progression.

CONCLUSION

In a cohort of diabetic patients with CKD in whom mean BP was < 140/80 mmHg, the potentially remediable factors hypoalbuminemia and proteinuria but not blood pressure were independently associated with progression of kidney disease. Further understanding of the relationship between these factors and kidney disease progression may lead to beneficial therapies in such patients.

Progression of nephropathy in type 2 diabetic patients

BACKGROUND

Nephropathy in type 2 diabetes is the single most common cause of end-stage renal disease (ESRD), but the decline in kidney function varies considerably between individuals, and determinants of renal function loss, early in the course of renal disease, have not been clearly identified.

METHODS

In a prospective observational study, we followed 227 (60 female) Caucasian type 2 diabetic patients with nephropathy for 6.5 (range 3 to 17) years from a baseline glomerular filtration rate (GFR) of 83 (SD30) mL/min/1.73m(2) with 7 (range 3 to 22) measurements of GFR ((51)Cr-EDTA) per patient. We evaluated determinants of (1) rate of decline in GFR, (2) risk of doubling in serum creatinine or ESRD, and (3) mortality using potential risk factors at baseline and during follow-up.

RESULTS

The mean (SD) rate of decline in GFR was 5.2 (4.1) mL/min/year. In multivariate regression analysis, higher baseline albuminuria, systolic blood pressure (SBP), hemoglobin A1c, GFR, age, and degree of diabetic retinopathy were significantly associated with increased rate of decline in GFR (R(2) (adj) 0.24). During follow-up, elevated mean albuminuria, SBP, hemoglobin A1c, and lower hemoglobin, heavy smoking, and presence of diabetic retinopathy were significantly associated with increased decline in GFR (R(2) (adj) 0.26). During follow-up, 63 patients had a doubling in serum creatinine or developed ESRD, and 79 patients died, primarily due to cardiovascular disease. In Cox regression analysis, higher baseline albuminuria, hemoglobin A1c, and SBP, together with lower GFR and hemoglobin, were significantly associated with shorter time to doubling of serum creatinine or ESRD. Higher baseline albuminuria, hemoglobin A1c, SBP, and age were significantly associated with increased mortality.

CONCLUSION

Our long-term prospective study of type 2 diabetic patients with nephropathy has revealed several modifiable risk factors of enhanced progression in kidney disease and increased mortality.

Poor prognosis in proteinuric type 2 diabetic patients with retinopathy: insights from the RENAAL study

BACKGROUND

Retinopathy is the clinical hallmark of generalized microangiopathy in diabetes.

AIM

To examine the relation of this abnormality to end-stage renal disease (ESRD) and death in type 2 diabetes.

DESIGN

Retrospective analysis.

METHODS

Of 1513 type 2 diabetic patients with nephropathy participating in the Reduction of Endpoints in NIDDM with the Angiotensin II Antagonist Losartan (RENAAL) study, 1456 (96.5%) were assessed at baseline by ophthalmoscopy or fundus photography. RENAAL was a multinational double masked, randomized, placebo-controlled intervention study, whose primary end-point was the composite of a doubling of the baseline serum creatinine concentration, end-stage renal disease (ESRD) or death.

RESULTS

Of those assessed at baseline, 65% had diabetic retinopathy. Patients with retinopathy had higher systolic blood pressure, albuminuria and lower glomerular filtration rate (GFR), haemoglobin and serum albumin values than those without. In univariate analyses, the presence of retinopathy was associated with a 44% increase in the primary composite end-point (hazard ratio 1.44, 95%CI 1.22-1.70, p < 0.001). Patients with retinopathy had a 52% increase in doubling of serum creatinine (p < 0.001), a 47% increased risk of ESRD (p = 0.002) and a 33% increase in risk of death (p = 0.026) compared to those without. In multivariate analyses, the presence of retinopathy was associated with a 23% increase (p = 0.015) in the primary composite end-point and a 22% increase in ESRD or death (p = 0.038).

DISCUSSION

The presence of diabetic retinopathy at baseline is associated with more proteinuria, lower GFR, and a higher risk for ESRD and death in type 2 diabetic patients.

Diabetic nephropathy: diagnosis, prevention, and treatment

Diabetic nephropathy is the leading cause of kidney disease in patients starting renal replacement therapy and affects approximately 40% of type 1 and type 2 diabetic patients. It increases the risk of death, mainly from cardiovascular causes, and is defined by increased urinary albumin excretion (UAE) in the absence of other renal diseases. Diabetic nephropathy is categorized into stages: microalbuminuria (UAE >20 microg/min and < or =199 microg/min) and macroalbuminuria (UAE > or =200 microg/min). Hyperglycemia, increased blood pressure levels, and genetic predisposition are the main risk factors for the development of diabetic nephropathy. Elevated serum lipids, smoking habits, and the amount and origin of dietary protein also seem to play a role as risk factors. Screening for microalbuminuria should be performed yearly, starting 5 years after diagnosis in type 1 diabetes or earlier in the presence of puberty or poor metabolic control. In patients with type 2 diabetes, screening should be performed at diagnosis and yearly thereafter. Patients with micro- and macroalbuminuria should undergo an evaluation regarding the presence of comorbid associations, especially retinopathy and macrovascular disease. Achieving the best metabolic control (A1c <7%), treating hypertension (<130/80 mmHg or <125/75 mmHg if proteinuria >1.0 g/24 h and increased serum creatinine), using drugs with blockade effect on the renin-angiotensin-aldosterone system, and treating dyslipidemia (LDL cholesterol <100 mg/dl) are effective strategies for preventing the development of microalbuminuria, in delaying the progression to more advanced stages of nephropathy and in reducing cardiovascular mortality in patients with type 1 and type 2 diabetes.

Clinical practice guidelines for managing dyslipidemias in kidney transplant patients: a report from the Managing Dyslipidemias in Chronic Kidney Disease Work Group of the National Kidney Foundation Kidney Disease Outcomes Quality Initiative

The incidence of cardiovascular disease (CVD) is very high in patients with chronic kidney (CKD) disease and in kidney transplant recipients. Indeed, available evidence for these patients suggests that the 10-year cumulative risk of coronary heart disease is at least 20%, or roughly equivalent to the risk seen in patients with previous CVD. Recently, the National Kidney Foundation's Kidney Disease Outcomes Quality Initiative (K/DOQI) published guidelines for the diagnosis and treatment of dyslipidemias in patients with CKD, including transplant patients. It was the conclusion of this Work Group that the National Cholesterol Education Program Guidelines are generally applicable to patients with CKD, but that there are significant differences in the approach and treatment of dyslipidemias in patients with CKD compared with the general population. In the present document we present the guidelines generated by this workgroup as they apply to kidney transplant recipients. Evidence from the general population indicates that treatment of dyslipidemias reduces CVD, and evidence in kidney transplant patients suggests that judicious treatment can be safe and effective in improving dyslipidemias. Dyslipidemias are very common in CKD and in transplant patients. However, until recently there have been no adequately powered, randomized, controlled trials examining the effects of dyslipidemia treatment on CVD in patients with CKD. Since completion of the K/DOQI guidelines on dyslipidemia in CKD, the results of the Assessment of Lescol in Renal Transplantation (ALERT) Study have been presented and published. Based on information from randomized trials conducted in the general population and the single study conducted in kidney transplant patients, these guidelines, which are a modified version of the K/DOQI dyslipidemia guidelines, were developed to aid clinicians in the management of dyslipidemias in kidney transplant patients. These guidelines are divided into four sections. The first section (Introduction) provides the rationale for the guidelines, and describes the target population, scope, intended users, and methods. The second section presents guidelines on the assessment of dyslipidemias (guidelines 1-3), while the third section offers guidelines for the treatment of dyslipidemias (guidelines 4-5). The key guideline statements are supported mainly by data from studies in the general population, but there is an urgent need for additional studies in CKD and in transplant patients. Therefore, the last section outlines recommendations for research.

Proteinuria in diabetic nephropathy: treatment and evolution

Diabetic nephropathy is characterized by increased urinary albumin excretion and loss of renal function. Increased urinary albumin (proteinuria) is a key component of this disease. Previously, its development led to end-stage renal disease with increased mortality and morbidity for diabetic patients versus nondiabetic patients. Several treatment strategies currently exist that can prevent, slow, and even reverse diabetic nephropathy. New trials suggest that a multidisciplinary approach focused on optimizing metabolic and hypertensive control, in addition to the use of angiotensin-converting enzyme inhibitors or angiotensin 2 receptor antagonists, is effective in halting the progression of disease. Screening and implementation of these strategies is needed to reverse the epidemic of diabetic renal disease.