Different clinical outcomes for cardiovascular events and mortality in chronic kidney disease according to underlying renal disease: the Gonryo study

External Validation of the Kidney Failure Risk Equation Among Urban Community-Based Chinese Patients With CKD

Rationale & Objective

The Kidney Failure Risk Equations have been proven to perform well in multinational databases, whereas validation in Asian populations is lacking. This study sought to externally validate the equations in a community-based chronic kidney disease cohort in China.

Study Design

A retrospective cohort study.

Setting & Participants

Patients with and estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2 dwelling in an industrialized coastal city of China.

Exposure

Age, sex, eGFR, and albuminuria were included in the 4-variable model, whereas serum calcium, phosphate, bicarbonate, and albumin levels were added to the previously noted variables in the 8-variable model.

Outcome

Initiation of long-term dialysis treatment.

Analytical Approach

Model discrimination, calibration, and clinical utility were evaluated by Harrell's C statistic, calibration plots, and decision curve analysis, respectively.

Results

A total of 4,587 participants were enrolled for validation of the 4-variable model, whereas 1,414 were enrolled for the 8-variable model. The median times of follow-up were 4.0 (interquartile range: 2.6-6.3) years for the 4-variable model and 3.4 (2.2-5.6) years for the 8-variable model. For the 4-variable model, the C statistics were 0.750 (95% CI: 0.615-0.885) for the 2-year model and 0.766 (0.625-0.907) for the 5-year model, whereas the values were 0.756 (0.629-0.883) and 0.774 (0.641-0.907), respectively, for the 8-variable model. Calibration was acceptable for both the 4-variable and 8-variable models. Decision curve analysis for the models at the 5-year scale performed better throughout different net benefit thresholds than the eGFR-based (<30 mL/min/1.73 m2) strategy.

Limitations

A large proportion of patients lack albuminuria measurements, and only a subset of population could provide complete data for the 8-variable equation.

Conclusions

The kidney failure risk equations showed acceptable discrimination and calibration and better clinical utility than the eGFR-based strategy for incidence of kidney failure among community-based urban Chinese patients with chronic kidney disease.

Biopsy-proven CKD etiology and outcomes: the Chronic Kidney Disease Japan Cohort (CKD-JAC) study

BACKGROUND

The Kidney Disease: Improving Global Outcomes guidelines advocate the cause-glomerular filtration rate (GFR)-albuminuria (CGA) classification for predicting outcomes. However, there is a dearth of data supporting the use of the cause of chronic kidney disease. This study aimed to address how to incorporate a prior biopsy-proven diagnosis in outcome prediction.

METHODS

We examined the association of biopsy-proven kidney disease diagnoses with kidney failure with replacement therapy (KFRT) and all-cause death before KFRT in patients with various biopsy-proven diagnoses (n = 778, analysis A) and patients with diabetes mellitus labeled with biopsy-proven diabetic nephropathy (DN), other biopsy-proven diseases and no biopsy (n = 1117, analysis B).

RESULTS

In analysis A, adding biopsy-proven diagnoses to the GFR-albuminuria (GA) classification improved the prediction of 8-year incidence of KFRT and all-cause death significantly regarding integrated discrimination improvement and net reclassification index. Fine-Gray (FG) models with KFRT as a competing event showed significantly higher subdistribution hazard ratios (SHRs) for all-cause death in nephrosclerosis {4.12 [95% confidence interval (CI) 1.11-15.2)], focal segmental glomerulosclerosis [3.77 (95% CI 1.09-13.1)]} and membranous nephropathy (MN) [2.91 (95% CI 1.02-8.30)] than in immunoglobulin A nephropathy (IgAN), while the Cox model failed to show significant associations. Crescentic glomerulonephritis had the highest risk of all-cause death [SHR 5.90 (95% CI 2.05-17.0)]. MN had a significantly lower risk of KFRT than IgAN [SHR 0.45 (95% CI 0.24-0.84)]. In analysis B, other biopsy-proven diseases had a lower risk of KFRT than biopsy-proven DN in the FG model, with death as a competing event [SHR 0.62 (95% CI 0.39-0.97)].

CONCLUSIONS

The CGA classification is of greater value in predicting outcomes than the GA classification.

NMR-Based Metabolomics in Differential Diagnosis of Chronic Kidney Disease (CKD) Subtypes

Chronic Kidney Disease (CKD) is considered as a major public health problem as it can lead to end-stage kidney failure, which requires replacement therapy. A prompt and accurate diagnosis, along with the appropriate treatment, can delay CKD's progression, significantly. Herein, we sought to determine whether CKD etiology can be reflected in urine metabolomics during its early stage. This is achieved through the analysis of the urine metabolic fingerprint from 108 CKD patients by means of Nuclear Magnetic Resonance (NMR) spectroscopy metabolomic analysis. We report the first NMR-metabolomics data regarding the three most common etiologies of CKD: Chronic Glomerulonephritis (IgA and Membranous Nephropathy), Diabetic Nephropathy (DN) and Hypertensive Nephrosclerosis (HN). Analysis aided a moderate glomerulonephritis clustering, providing characterization of the metabolic fluctuations between the CKD subtypes and control disease. The urine metabolome of IgA Nephropathy reveals a specific metabolism, reflecting its different etiology or origin and is useful for determining the origin of the disease. In contrast, urine metabolomes from DN and HN patients did not reveal any indicative metabolic pattern, which is consistent with their fused clinical phenotype. These findings may contribute to improving diagnostics and prognostic approaches for CKD, as well as improving our understanding of its pathology.

Temporary central venous catheter at hemodialysis initiation and reasons for use: a cross-sectional study

Background

Creating permanent vascular access (VA) is recommended before hemodialysis initiation in patients with end-stage renal disease (ESRD). Although many patients are still introduced to hemodialysis with temporary central venous catheters (CVCs), the reasons for their use remain unclear. We aimed to clarify the characteristics of Japanese patients introduced to hemodialysis using temporary CVCs, the reasons for their use, and whether this rate can be reduced in the future.

Methods

We conducted this cross-sectional study in an acute care general hospital in Japan. We enrolled 393 patients aged ≥ 18 years who received a permanent VA creation for initiating hemodialysis. We classified participants into the temporary CVC group or the permanent VA group according to the VA type at hemodialysis initiation and compared their backgrounds. We identified why permanent VA could not be used at hemodialysis initiation for patients in the temporary CVC group.

Results

Of the 393 patients, 137 (35%) initiated hemodialysis with a temporary CVC, and arteriovenous fistulas (AVFs) were created as the first VA in all patients during hospitalization following hemodialysis initiation. The remaining 256 patients (65%) initiated hemodialysis via AVF cannulation. The duration of predialysis nephrology care was significantly shorter in the temporary CVC group than that in the permanent VA group. The median time from AVF creation to the first successful cannulation was also shorter in the temporary CVC group (8 vs. 66 days, P < 0.001), but the estimated glomerular filtration rate values at hemodialysis initiation did not differ. Reasons for temporary CVC use were varied and complex. Problems on the part of healthcare providers, patient behavioral issues, and characteristics of causative kidney disease itself were underlying reasons. Delayed referral to a nephrologist was less frequent than expected (16%) and the most commonly reported reason (20%) was that a nephrologist was unable to predict the timing of hemodialysis initiation.

Conclusions

Patients with ESRD should be referred to a nephrologist earlier for AVF creation. However, given the already relatively high rate of hemodialysis initiation with permanent VA in Japan, we considered it surprisingly difficult to further reduce the temporary CVC usage rate in Japan.

Molecular Mechanisms of SGLT2 Inhibitor on Cardiorenal Protection

The development of sodium-glucose transporter 2 inhibitor (SGLT2i) broadens the therapeutic strategies in treating diabetes mellitus. By inhibiting sodium and glucose reabsorption from the proximal tubules, the improvement in insulin resistance and natriuresis improved the cardiovascular mortality in diabetes mellitus (DM) patients. It has been known that SGLT2i also provided renoprotection by lowering the intraglomerular hypertension by modulating the pre- and post- glomerular vascular tone. The application of SGLT2i also provided metabolic and hemodynamic benefits in molecular aspects. The recent DAPA-CKD trial and EMPEROR-Reduced trial provided clinical evidence of renal and cardiac protection, even in non-DM patients. Therefore, the aim of the review is to clarify the hemodynamic and metabolic modulation of SGLT2i from the molecular mechanism.

Impact of lower body mass index on risk of all-cause mortality and infection-related death in Japanese chronic kidney disease patients

Background

Several studies have reported that lower body mass index (BMI) is associated with high mortality in patients with chronic kidney disease (CKD). Rate of infection-related death in CKD patients is increasing. However, the relationship between BMI and infection-related death is unclear.

Methods

Overall, 2648 CKD outpatients (estimated glomerular filtration rate < 60 mL/min and/or presenting with proteinuria) under the care of nephrologists were prospectively followed for 5 years. Patients were stratified by quartile of BMI levels. Data on all-cause mortality before progression to end-stage kidney disease (ESKD) and the cause of death were collected.

Results

The median follow-up time was 3.9 years (interquartile range, 1.7–5.0); 114 patients died and 308 started renal replacement therapy. The leading causes of death were as follows; cardiovascular (41%), infection-related (21%), and malignancy-related (18%). Advanced age and lower BMI were the significant risk factors for all-cause mortality before progression to ESKD. Advanced age was statistically associated with respective causes of death, while lower BMI was associated with infection-related death only. CKD stage had no significant impact on all-cause or individual mortality.

Conclusions

Low BMI was associated with significant risk of all-cause mortality and infection-related death, which may indicate the novel clinical target to improve CKD outcomes.

Blood pressure control in chronic kidney disease according to underlying renal disease: the Fukushima CKD cohort

BACKGROUND

Inadequate blood pressure control is one of the important causes of chronic kidney disease (CKD), but only a limited number of reports have examined blood pressure control in Japanese patients with pre-dialysis CKD. Differences in blood pressure control due to underlying renal disease in pre-dialysis patients with CKD were investigated in the present study using the baseline data of the Fukushima CKD cohort study.

METHODS

The study involved 1351 CKD patients, classified by underlying disease of primary renal disease, hypertensive nephropathy, diabetic nephropathy, other nephropathies, or unknown. Target blood pressure of CKD patients was defined as < 130/80 mmHg in patients under 75 years old with diabetes and/or proteinuria, and < 140/90 mmHg in other patients.

RESULTS

The achievement rate of target systolic blood pressure was lower in the diabetic and hypertensive nephropathy groups than in the primary renal disease group (33.3%, 46.0% vs. 68.1%, p < 0.001). However, the number of antihypertensive medications increased in the diabetic and hypertensive nephropathy groups compared to the primary renal disease group (2.16, 2.04 vs. 1.55, p < 0.001). Inadequate blood pressure control was independently related to the underlying renal disease, with a significant difference between diabetic nephropathy and primary renal disease (odds ratio 3.19; 95% confidence interval, 2.16-4.69; p < 0.001).

CONCLUSION

This study showed that blood pressure control differs by the underlying renal disease. Blood pressure control was poor especially in diabetic nephropathy despite multidrug combination antihypertensive treatment. It is necessary to verify whether strict blood pressure control improves patients' prognosis in diabetic nephropathy.

Unmet medical needs in intermittent Claudication with diabetes and coronary artery disease-A "real-world" analysis on 21 197 PAD patients

BACKGROUND

Peripheral artery disease (PAD) is frequently co-prevalent with coronary artery disease (CAD) and diabetes (DM). The study aims to define the burden of CAD and/ or DM in PAD patients at moderate stages and further to evaluate its impact on therapy and outcome.

METHODS

Study is based on health insurance claims data of the BARMER reflecting an unselected "real-world" scenario. Retrospective analyses were based on 21 197 patients hospitalized for PAD Rutherford 1-3 between 1 January 2009 to 31 December 2011, including a 4-year follow-up (median 775 days).

RESULTS

In PAD patients, CAD is prevalent in 25.3% (n = 5355), DM in 23.5% (n = 4976), and both CAD and DM in 8.2% (n = 1741). Overall, in-hospital mortality was 0.4%, being increased if CAD was present (CAD alone: OR 1.849; 95%-CI 1.066-3.208; DM alone: OR 1.028; 95%-CI 0.520-2.033; CAD and DM: OR 3.115; 95%-CI 1.720-5.641). Both, CAD and DM increased long-term mortality (CAD alone: HR 1.234; 95%-CI 1.106-1.376; DM alone: HR 1.260; 95%-CI 1.125-1.412; CAD and DM: HR 1.76; 95%-CI 1.552-1.995). DM further increased long-term amputation risk (DM alone: HR 2.238; 95%-CI 1.849-2.710; DM and CAD: HR 2.199; 95%-CI 1.732-2.792), whereas CAD (alone) did not.

CONCLUSIONS

In a greater perspective, the data identify also mild to modest stage PAD patients at particular risk for adverse outcomes in presence of CAD and/or DM. CAD and DM both are related with a highly increased risk of long-term mortality even in intermittent claudication, and DM independently increased amputation risk.

Contrast-Induced Nephropathy and Long-Term Clinical Outcomes Following Percutaneous Coronary Intervention in Patients With Advanced Renal Dysfunction (Estimated Glomerular Filtration Rate <30 ml/min/1.73 m2)

The incidence of contrast-induced nephropathy (CIN) increases with the progression of renal dysfunction. Recent reports have shown that percutaneous coronary intervention (PCI) can be safely performed even in patients with advanced renal dysfunction by appropriate CIN-prevention strategies. However, data are limited regarding the occurrence and prognostic influence of CIN in patients with advanced renal dysfunction. We examined the data obtained from 323 consecutive patients with advanced renal dysfunction (eGFR <30 ml/min/1.73 m²) who underwent PCI at 5 hospitals. CIN was defined as a ≥25% increase in baseline serum creatinine levels and/or a ≥0.5 mg/dl increase in absolute serum creatinine levels within 72 hours after PCI. Incidence of all-cause death and the initiation of permanent dialysis were examined during follow-up. The prevalence of emergency/urgent PCI was 53.3%. Intravascular ultrasound was used in 266 patients (82.4%), and the volume of contrast used was 71.7 ± 57.2 ml. CIN was observed in 31 patients (9.7%). The median follow-up duration was 656 days (interquartile range 257-1143 days). The cumulative rates of all-cause death or the initiation of permanent dialysis, all-cause death, and the initiation of permanent dialysis were 38.1%, 25.9%, and 18.2%, respectively, at 2 years. A comparison between patients with and without CIN showed no significant intergroup differences in the occurrence of the aforementioned events. In conclusion, the incidence of CIN was not high in Japanese patients with advanced renal dysfunction in routine clinical practice. Whereas, the long-term prognosis following PCI is observed to be poor in this studied population, and CIN did not show a significant prognostic influence.

Clinical prediction models for progression of chronic kidney disease to end-stage kidney failure under pre-dialysis nephrology care: results from the Chronic Kidney Disease Japan Cohort Study

Background

Reliable prediction tools are needed to identify patients with chronic kidney disease (CKD) at greater risk of developing end-stage kidney failure (ESKF). We developed and validated clinical prediction models (CPMs) for CKD progression to ESKF under pre-dialysis nephrology care using CKD-Japan Cohort (CKD-JAC) data.

Methods

We prospectively followed up 2034 participants with CKD, defined as an estimated glomerular filtration rate (eGFR) less than 60 mL/min/1.73 m², aged 20–75 years for a mean of 3.15 years. We randomly divided the overall analysis set into development and validation cohorts. In the development cohort, CPMs were developed using Cox proportional hazard regression, and the goodness of fit was evaluated. In the validation cohort, discrimination and calibration of the developed CPMs were evaluated. We also validated developed CPMs in the dataset with the bootstrap method.

Results

ESKF onset was observed in 206 and 216 patients in the development (20.3%) and validation (21.2%) cohorts, respectively. Goodness of fit, discrimination, and calibration were worse for a simple model including age, sex, and eGFR than for a complicated model (plus albuminuria, systolic blood pressure, diabetes, serum albumin, and hemoglobin). The mean absolute difference between the observed and predictive probabilities of ESKF onset at 3 years was lower for the complicated model than for the simple model (1.57 vs. 1.87%).

Conclusions

CPMs employing readily available data could precisely predict progression to ESKF in patients with CKD stage G3a to G5. These developed CPMs may facilitate more appropriate clinical care and shared decision-making between clinicians and patients.

Electronic supplementary material

The online version of this article (10.1007/s10157-018-1621-z) contains supplementary material, which is available to authorized users.

Canagliflozin reduces plasma uremic toxins and alters the intestinal microbiota composition in a chronic kidney disease mouse model

Accumulation of uremic toxins, which exert deleterious effects in chronic kidney disease, is influenced by the intestinal environment; the microbiota contributes to the production of representative uremic toxins, including p-cresyl sulfate and indoxyl sulfate. Canagliflozin is a sodium-glucose cotransporter (SGLT) 2 inhibitor, and it also exerts a modest inhibitory effect on SGLT1. The inhibition of intestinal SGLT1 can influence the gastrointestinal environment. We examined the effect of canagliflozin on the accumulation of uremic toxins in chronic kidney disease using adenine-induced renal failure mice. Two-week canagliflozin (10 mg/kg po) treatment did not influence the impaired renal function; however, it significantly reduced the plasma levels of p-cresyl sulfate and indoxyl sulfate in renal failure mice (a 75% and 26% reduction, respectively, compared with the vehicle group). Additionally, canagliflozin significantly increased cecal short-chain fatty acids in the mice, suggesting the promotion of bacterial carbohydrate fermentation in the intestine. Analysis of the cecal microbiota showed that canagliflozin significantly altered microbiota composition in the renal failure mice. These results indicate that canagliflozin exerts intestinal effects that reduce the accumulation of uremic toxins including p-cresyl sulfate. Reduction of accumulated uremic toxins by canagliflozin could provide a potential therapeutic option in chronic kidney disease.

Quantification of bleeding volume using computed tomography and clinical complications after percutaneous renal biopsy

Background: The aim of this study was to investigate specific bleeding volume after percutaneous renal biopsy (PRB) and the correlation between bleeding volume and clinical parameters.

Methods: A retrospective study of 252 consecutive patients (153 male patients and 99 female patients) who underwent PRB at the Department of Nephrology, Japanese Red Cross Ishinomaki Hospital, between July 2013 and January 2016 was conducted. PRB was performed under ultrasound guidance using an automated spring-loaded biopsy device and a 16-cm, 16-gauge needle. Patients underwent computed tomography (CT) the day after PRB. Bleeding volume after PRB was evaluated using reconstructed CT data.

Results: The median bleeding volume after PRB was 38 mL (25th–75th percentile, 18–85 mL), with ≥4 punctures identified as a risk factor for massive bleeding. The incidence rates of macrohematuria, transient hypotension and bladder obstruction were 14.3, 8.7 and 4.7%, respectively. Post-PRB blood transfusion and intervention were required in 4.7 and 0.8% of patients, respectively.

Conclusion: Although it is difficult to assess the risk for massive bleeding prior to PRB, we do provide evidence of a specific increased risk with ≥4 puncture attempts, and recommend careful follow-up of these patients.

Early rehospitalization after initial chronic kidney disease educational hospitalization relates with a multidisciplinary medical team

Background

It is well-documented that chronic kidney disease (CKD) often results in end-stage renal failure and puts patients at extremely high risk for developing cardiovascular disease. Educational hospitalization at medical institutions in Japan is important for patients with CKD because it facilitates treatment in earlier stages of CKD when subjective symptoms are not apparent. However, some patients who have achieved their educational targets tend to have poor compliance at home after discharge from the hospital, resulting in rehospitalization shortly. In this study, we examined the factors for early rehospitalization of patients after initial CKD educational hospitalization compared with non-rehospitalized patients.

Methods

One hundred thirty-seven patients after discharge from CKD educational hospitalization in Japan between March 2011 and December 2012 were included in the analyses. The subjects were classified into two groups: the early rehospitalization group and control group. We adjusted for confounding variables and performed multiple logistic regression analysis with the presence or absence of early rehospitalization as a dependent variable to investigate the association of early rehospitalization with patient background features, laboratory data, vital signs, instruction-related items, and home environment.

Results

Study subjects included 22 patients in the early hospitalization group and 115 patients in control group. Multivariable analysis for early rehospitalization indicated that insufficient instruction by physician, pharmacist, and dietitians was independent explanatory variable. Analyzing by Kaplan–Meier method, the probability of non-rehospitalization in the instruction group was significantly higher than that in the non-instruction group. Therefore, we believe it is necessary to involve a competent, multidisciplinary medical team (consisting of physicians, pharmacists, and dietitians) in addressing the early rehospitalization issue in patients with CKD.

Conclusion

These findings confirm the importance of care by a multidisciplinary medical team in patients with CKD. Therefore, we suggest that care by a multidisciplinary medical team reduces the increase of early rehospitalization in patients with CKD.

Relationship between Estimated Glomerular Filtration Rate and Cardiovascular Mortality in a Japanese Cohort with Long-Term Follow-Up

BACKGROUND

Patients with renal impairment are at risk of not only end-stage kidney disease but also cardiovascular disease (CVD). The current definition of CKD stage G3a is eGFR 45-59 ml/min/1.73 m2 and of G3b is 30-44 ml/min/1.73 m2, and subjects in the CKD 3a category are considered to be at lower risk of mortality than are those in CKD 3b.

METHODS

We evaluated the outcome of 97,043 people (33,131 men and 63,912 women) living in Ibaraki Prefecture who underwent annual community-based health checkups beginning in 1993 at age 40-80 years and who were followed for a mean of 17.1 years.

RESULTS

The number of all-causes deaths was 20,534 (10,375 men and 10,159 women), of which 5,995 (2,695 men and 3,300 women) were deaths due to CVD. Multivariable-adjusted hazard ratio for CVD death in the eGFR 45-49 ml/min/1.73 m2 category was significantly increased (1.82; 95% confidential interval, 1.23-2.69) in non-elderly men, whereas all-cause mortality and CVD mortality in elderly men with eGFR 45-49 ml/min/1.73m2 were non significant. In contrast, both in non-elderly women and in elderly women with eGFR 45-49 ml/min/1.73 m2 showed small, but significant, increases in the risks of all-cause mortality and CVD.

CONCLUSIONS

We demonstrated proportionate increases in mortality with decreasing eGFR in a Japanese CKD population. Like patients in the CKD G3b subgroup, non-elderly men and women with an eGFR of 45-49 ml/min/1.73 m2 (i.e. a part of CKD G3a) are at considerable risk of CVD mortality. Age dependent and eGFR dependent finer risk recognition were required for CVD prevention in clinical practice with regard to CKD patients.

Effect of Behavior Modification on Outcome in Early- to Moderate-Stage Chronic Kidney Disease: A Cluster-Randomized Trial

OBJECTIVES

Owing to recent changes in our understanding of the underlying cause of chronic kidney disease (CKD), the importance of lifestyle modification for preventing the progression of kidney dysfunction and complications has become obvious. In addition, effective cooperation between general physicians (GPs) and nephrologists is essential to ensure a better care system for CKD treatment. In this cluster-randomized study, we studied the effect of behavior modification on the outcome of early- to moderate-stage CKD.

DESIGN

Stratified open cluster-randomized trial.

SETTING

A total of 489 GPs belonging to 49 local medical associations (clusters) in Japan.

PARTICIPANTS

A total of 2,379 patients (1,195 in group A (standard intervention) and 1,184 in group B (advanced intervention)) aged between 40 and 74 years, who had CKD and were under consultation with GPs.

INTERVENTION

All patients were managed in accordance with the current CKD guidelines. The group B clusters received three additional interventions: patients received both educational intervention for lifestyle modification and a CKD status letter, attempting to prevent their withdrawal from treatment, and the group B GPs received data sheets to facilitate reducing the gap between target and practice.

MAIN OUTCOME MEASURE

The primary outcome measures were 1) the non-adherence rate of accepting continuous medical follow-up of the patients, 2) the collaboration rate between GPs and nephrologists, and 3) the progression of CKD.

RESULTS

The rate of discontinuous clinical visits was significantly lower in group B (16.2% in group A vs. 11.5% in group B, p = 0.01). Significantly higher referral and co-treatment rates were observed in group B (p<0.01). The average eGFR deterioration rate tended to be lower in group B (group A: 2.6±5.8 ml/min/1.73 m2/year, group B: 2.4±5.1 ml/min/1.73 m2/year, p = 0.07). A significant difference in eGFR deterioration rate was observed in subjects with Stage 3 CKD (group A: 2.4±5.9 ml/min/1.73 m2/year, group B: 1.9±4.4 ml/min/1.73 m2/year, p = 0.03).

CONCLUSION

Our care system achieved behavior modification of CKD patients, namely, significantly lower discontinuous clinical visits, and behavior modification of both GPs and nephrologists, namely significantly higher referral and co-treatment rates, resulting in the retardation of CKD progression, especially in patients with proteinuric Stage 3 CKD.

TRIAL REGISTRATION

The University Hospital Medical Information Network clinical trials registry UMIN000001159.

Estimating time to ESRD using kidney failure risk equations: results from the African American Study of Kidney Disease and Hypertension (AASK)

BACKGROUND

Planning for renal replacement therapy, such as referral for arteriovenous fistula placement and transplantation, often is guided by level of estimated glomerular filtration rate (eGFR). The use of risk equations might enable more accurate estimation of time to end-stage renal disease (ESRD), thus improving patient care.

STUDY DESIGN

Prospective observational study.

SETTING & PARTICIPANTS

1,094 participants in the African American Study of Kidney Disease and Hypertension (AASK) cohort.

PREDICTOR

Age, sex, urine protein-creatinine ratio ≥ 1g/g, APOL1 high-risk status, and 3-year antecedent eGFR decline.

OUTCOME

Cumulative incidence of ESRD from 5 different starting points: eGFR of 30 and 15mL/min/1.73m(2) and 1-year ESRD risk of 5%, 10%, and 20%, estimated by a published 4-variable kidney failure risk equation.

RESULTS

566 participants developed eGFR of 30mL/min/1.73m(2), 244 developed eGFR of 15mL/min/1.73m(2), and 437, 336, and 259 developed 1-year ESRD risks of 5%, 10%, and 20%, respectively. The 1-year cumulative incidence of ESRD was 4.3% from eGFR of 30mL/min/1.73m(2), 49.0% from eGFR of 15mL/min/1.73m(2), 6.7% from 5% ESRD risk, 15.0% from 10% ESRD risk, and 29% from 20% ESRD risk. From eGFR of 30mL/min/1.73m(2), there were several risk factors that predicted ESRD risk. From eGFR of 15mL/min/1.73m(2), only level of proteinuria did; median time to ESRD was 9 and 19 months in those with higher and lower proteinuria, respectively. Median times were less variable from corresponding ESRD risk thresholds. For example, median times to ESRD from 20% ESRD risk were 22 and 25 months among those with higher and lower proteinuria, respectively.

LIMITATIONS

Relatively homogeneous population of African Americans with hypertensive kidney disease.

CONCLUSIONS

Results of the present study suggest the potential benefit of incorporating kidney failure risk equations into clinical care, with selection of a specific threshold guided by its intended use.

Prevalence and incidence of chronic kidney disease stage G5 in Japan

The prevalence and incidence of end-stage kidney disease (ESKD) have continued to increase worldwide. Japan was known as having the highest prevalence of ESKD in the world; however, Taiwan took this place in 2001, with the USA still in third position. However, the prevalence data from Japan and Taiwan consisted of dialysis patients only. The prevalence and incidence of Kidney Transplantation (KT) in Japan were quite low, and the number of KT patients among those with ESKD was regarded as negligibly small. However, the number of KT recipients has increased recently. Furthermore, there are no reports about nationwide surveys on the prevalence and incidence of predialysis chronic kidney failure patients in Japan. This review describes our recent study on the estimated number of chronic kidney disease (CKD) stage G5 patients and the number of ESKD patients living in Japan, obtained via the cooperation of five related medical societies. From the results, as of Dec 31, 2007, 275,242 patients had received dialysis therapy and 10,013 patients had a functional transplanted kidney, and as of Dec 31, 2008, 286,406 patients had received dialysis therapy and 11,157 patients had a functional transplanted kidney. Consequently, there were 285,255 patients with CKD who reached ESKD and were living in Japan in 2008 and 297,563 in 2009. We also estimated that there were 67,000 predialysis CKD stage G5 patients in 2009, 37,365 patients introduced to dialysis therapy, and 101 patients who received pre-emptive renal transplantation in this year. In total, there were 37,466 patients who newly required renal replacement therapy (RRT) in 2009. Not only the average ages, but also the primary renal diseases of the new ESKD patients in each RRT modality were different.

Health-related quality of life and prognosis in patients with chronic kidney disease: a 3-year follow-up study

BACKGROUND

Chronic kidney disease (CKD) is a major global problem and is also associated with a decreased health-related quality of life (HRQOL). The aim of this study was to evaluate measured HRQOL based on the new CKD classification including proteinuria stage, and the effect of measured HRQOL on CKD progression and clinical outcomes over a 3-year period.

METHODS

EuroQol (EQ-5D), a generic preference-based questionnaire, was administered to 537 CKD outpatients at the University of Tsukuba Hospital between November and December 2008. We evaluated disease progression in CKD patients including the incidence of end-stage kidney disease (ESKD), cardiovascular disease (CVD) and all-cause mortality over a 3-year follow-up period.

RESULTS

The proportions progressing to the higher stages were 32.6, 20.0, 36.6, 39.5, and 45.8 % from glomerular filtration rate (GFR) stages (G) 1-4, respectively. The proportion progressing to ESKD (G5D) was 0.7 % from G2, 3.9 % from G3b, 20.8 % from G4 and 63.4 % from G5. The incidence of CVD and/or death was 1.2, 4.6, 4.9, 5.3, 8.3 and 21.1 % from G1-G5, respectively. The quality-adjustment weights at G4-5 were significantly lower than at G1-2 and the weights at proteinuria stage (A) 3 were significantly lower than at A1-2. The quality-adjustment weights of patients with events such as 50 % estimated GFR decline, dialysis, CVD, and/or death were significantly lower than those without events.

CONCLUSION

We showed CKD progression and clinical outcomes over a 3-year period. Quality-adjustment weights in CKD patients were associated with not only disease progression such as initiation of dialysis treatment and incidence of CVD events and all-cause death, but also the level of proteinuria at baseline.

Clinical impact of albuminuria and glomerular filtration rate on renal and cardiovascular events, and all-cause mortality in Japanese patients with type 2 diabetes

BACKGROUND

The number of patients suffering from diabetic nephropathy resulting in end-stage kidney disease is increasing worldwide. In clinical settings, there are limited data regarding the impact of the urinary albumin-to-creatinine ratio (UACR) and reduced estimated glomerular filtration rate (eGFR) on renal and cardiovascular outcomes and all-cause mortality.

METHODS

We performed a historical cohort study of 4328 Japanese participants with type 2 diabetes from 10 centers. Risks for renal events (requirement for dialysis or transplantation, or half reduction in eGFR), cardiovascular events (cardiovascular death, nonfatal myocardial infarction, or nonfatal stroke), and all-cause mortality were assessed according to UACR and eGFR levels.

RESULTS

During follow-up (median 7.0 years, interquartile range 3.0-8.0 years), 419 renal events, 605 cardiovascular events and 236 deaths occurred. The UACR levels increased the risk and the adjusted hazard ratios for these three events. In addition to the effects of UACR levels, eGFR stages significantly increased the adjusted hazard ratios for renal events and all-cause mortality, especially in patients with macroalbuminuria. Diabetic nephropathy score, based on the prognostic factors, well predicted incidence rates per 1000 patient/year for each event.

CONCLUSIONS

Increased UACR levels were closely related to the increase in risks for renal, cardiovascular events and all-cause mortality in Japanese patients with type 2 diabetes, whereas the association between high levels of UACR and reduced eGFR was a strong predictor for renal events.

Rationale and trial design of Bardoxolone Methyl Evaluation in Patients with Chronic Kidney Disease and Type 2 Diabetes: the Occurrence of Renal Events (BEACON)

BACKGROUND

Chronic kidney disease (CKD) associated with type 2 diabetes mellitus constitutes a global epidemic complicated by considerable renal and cardiovascular morbidity and mortality, despite the provision of inhibitors of the renin-angiotensin-aldosterone system (RAAS). Bardoxolone methyl, a synthetic triterpenoid that reduces oxidative stress and inflammation through Nrf2 activation and inhibition of NF-κB was previously shown to increase estimated glomerular filtration rate (eGFR) in patients with CKD associated with type 2 diabetes mellitus. To date, no antioxidant or anti-inflammatory therapy has proved successful at slowing the progression of CKD.

METHODS

Herein, we describe the design of Bardoxolone Methyl Evaluation in Patients with Chronic Kidney Disease and Type 2 Diabetes: the Occurrence of Renal Events (BEACON) trial, a multinational, multicenter, double-blind, randomized, placebo-controlled Phase 3 trial designed to determine whether long-term administration of bardoxolone methyl (on a background of standard therapy, including RAAS inhibitors) safely reduces renal and cardiac morbidity and mortality.

RESULTS

The primary composite endpoint is time-to-first occurrence of either end-stage renal disease or cardiovascular death. Secondary endpoints include the change in eGFR and time to occurrence of cardiovascular events.

CONCLUSION

BEACON will be the first event-driven trial to evaluate the effect of an oral antioxidant and anti-inflammatory drug in advanced CKD.

Effect of allopurinol on cardiovascular incidence among hypertensive nephropathy patients: the Gonryo study

BACKGROUND

The present study aimed to clarify the beneficial effect of allopurinol on cardiovascular morbidity and mortality in a cohort of hypertensive nephropathy patients with impaired kidney function.

METHODS

One hundred and seventy-eight patients diagnosed with hypertensive nephropathy and presenting with impaired kidney function (estimated glomerular filtration rate <45 mL/min/1.73 m(2)) were recruited from nephrology clinics. Oral allopurinol was prescribed in 67 of these patients. The effects of allopurinol use on the development of cardiovascular disease (i.e. ischemic heart disease, congestive heart failure, and stroke) and all-cause death was analyzed using the Cox proportional hazard model.

RESULTS

During the follow-up of 18.4 months (mean), 28 primary events occurred. Basal use of allopurinol was a significant beneficial factor (hazard ratio = 0.342, p = 0.0434, standard error = 0.53058) after adjusting for confounding factors.

CONCLUSION

The use of allopurinol in hypertensive subjects with impaired kidney function appears to be beneficial in preventing cardiovascular morbidity and all-cause mortality, indicating that this xanthine oxidase inhibitor protects the vascular system, at least in this specific group.

Association of glomerular filtration rate with high-sensitivity cardiac troponin T in a community-based population study in Beijing

BACKGROUND

Reduced renal function is an independent risk factor for cardiovascular disease mortality, and persistently elevated cardiac troponin T (cTnT) is frequently observed in patients with end-stage renal disease. In the general population the relationship between renal function and cTnT levels may not be clear because of the low sensitivity of the assay. In this study, we investigated the level of cTnT using a highly sensitive assay (hs-cTnT) and evaluated the association of estimated glomerular filtration rate (eGFR) with detectable hs-cTnT levels in a community-based population.

METHODS

The serum hs-cTnT levels were measured in 1365 community dwelling population aged ≥45 years in Beijing, China. eGFR was determined by the Chinese modifying modification of diet in renal disease (C-MDRD) equation.

RESULTS

With the highly sensitive assay, cTnT levels were detectable (≥3pg/mL) in 744 subjects (54.5%). The result showed that eGFR was associated with Log hs-cTnT (r = -0.14, P<0.001). After adjustment for the high predicted Framingham Coronary Heart Disease (CHD) risk (10-year risk >20%) and other prognostic indicators, moderate to severe reduced eGFR was independently associated with detectable hs-cTnT, whereas normal to mildly reduced eGFR was not independently associated with detectable hs-cTnT. In addition, after adjustment for other risk factors, the high predicted Framingham CHD risk was associated with detectable hs-cTnT in the subjects with different quartile levels of eGFR.

CONCLUSION

The levels of hs-cTnT are detectable in a community-based Chinese population and low eGFR is associated with detectable hs-cTnT. Moreover, eGFR and high predicted Framingham CHD risk are associated with detectable hs-cTnT in subjects with moderate-to-severe reduced renal function.

Predicting the outcome of chronic kidney disease by the estimated nephron number: the rationale and design of PRONEP, a prospective, multicenter, observational cohort study

BACKGROUND

The nephron number is thought to be associated with the outcome of chronic kidney disease (CKD). If the nephron number can be estimated in the clinical setting, it could become a strong tool to predict renal outcome. This study was designed to estimate the nephron number in CKD patients and to establish a method to predict the outcome by using the estimated nephron number.

METHODS/DESIGN

The hypothesis of this study is that the estimated nephron number can predict the outcome of a CKD patient. This will be a multicenter, prospective (minimum 3 and maximum 5 years follow-up) study. The subjects will comprise CKD patients aged over 14 years who have undergone a kidney biopsy. From January 2011 to March 2013, we will recruit 600 CKD patients from 10 hospitals belonging to the National Hospital Organization of Japan. The primary parameter for assessment is the composite of total mortality, renal death, cerebro-cardiovascular events, and a 50% reduction in the eGFR. The secondary parameter is the rate of eGFR decline per year. The nephron number will be estimated by the glomerular density in biopsy specimens and the renal cortex volume. This study includes one sub-cohort study to establish the equation to calculate the renal cortex volume. Enrollment will be performed at the time of the kidney biopsy, and the data will consist of a medical interview, ultrasound for measurement of the kidney size, blood or urine test, and the pathological findings of the kidney biopsy. Patients will continue to have medical consultations and receive examinations and/or treatment as usual. The data from the patients will be collected once a year after the kidney biopsy until March 2016. All data using this study are easily obtained in routine clinical practice.

DISCUSSION

This study includes the first trials to estimate the renal cortex volume and nephron number in the general clinical setting. Furthermore, this is the first prospective study to examine whether the nephron number predicts the outcome of CKD patients. The results from this study should provide powerful new tools for nephrologists in routine clinical practice.

TRIAL REGISTRATION

UMIN-Clinical Trial Registration, UMIN000004784.

Association of blood pressure with decline in renal function and time until the start of renal replacement therapy in pre-dialysis patients: a cohort study

Background

To investigate whether high blood pressure accelerates renal function decline in patients with advanced chronic kidney disease (CKD), we studied the association of systolic (SBP) and diastolic blood pressure (DBP) with decline in renal function and time until the start of renal replacement therapy (RRT) in patients with CKD stages IV-V on pre-dialysis care.

Methods

In the PREPARE-1 cohort 547 incident pre-dialysis patients, referred as part of the usual care to outpatient clinics of eight Dutch hospitals, were included between 1999 and 2001 and followed until the start of RRT, mortality, or end of follow-up (January 1^st 2008). Main outcomes were rate of decline in renal function, estimated as the slope of available eGFR measurements, and time until the start of RRT.

Results

A total of 508 patients, 57% men and median (IQR) age of 63 (50-73) years, were available for analyses. Mean (SD) decline in renal function was 0.35 (0.75) ml/min/1.73 m²/month. Every 10 mmHg increase in SBP or DBP resulted in an accelerated decline in renal function (adjusted additional decline 0.04 (0.02;0.07) and 0.05 (0.00;0.11) ml/min/1.73 m²/month respectively) and an earlier start of RRT (adjusted HR 1.09 (1.04;1.14) and 1.16 (1.05;1.28) respectively). Furthermore, patients with SBP and DBP above the BP target goal of < 130/80 mmHg experienced a faster decline in renal function (adjusted additional decline 0.31 (0.08;0.53) ml/min/1.73 m²/month) and an earlier start of RRT (adjusted HR 2.08 (1.25;3.44)), compared to patients who achieved the target goal (11%). Comparing the decline in renal function and risk of starting RRT between patients with only SBP above the target (≥ 130 mmHg) and patients with both SBP and DBP below the target (< 130/80 mmHg), showed that the results were almost similar as compared to patients with both SBP and DBP above the target (adjusted additional decline 0.31 (0.04;0.58) ml/min/1.73 m²/month and adjusted HR 2.24 (1.26;3.97)). Therefore, it seems that especially having SBP above the target is harmful.

Conclusions

In pre-dialysis patients with CKD stages IV-V, having blood pressure (especially SBP) above the target goal for CKD patients (< 130/80 mmHg) was associated with a faster decline in renal function and a later start of RRT.

Clinical impact of albuminuria in diabetic nephropathy

Patients suffering from diabetic nephropathy, resulting in end-stage renal failure, are increasing in number. The pathophysiology of diabetic nephropathy remains to be fully investigated. In the clinical setting, the presence of albuminuria/overt proteinuria and a low glomerular filtration rate may predict poor renal prognosis, but the prognosis of the normoalbuminuric renally insufficient diabetic patient remains controversial. In addition to the measurement of urinary albumin excretion, biomarker studies to detect diabetic nephropathy more specifically at the early stage have been performed worldwide. There is a growing body of evidence for remission and/or regression of diabetic nephropathy, which may be an indicator for cardiovascular and renal risk reduction. Deeper insights into the pathological characteristics as well as the clinical impact of albuminuria on renal and cardiovascular outcome are required.

Increased risk of cardiovascular events and mortality among non-diabetic chronic kidney disease patients with hypertensive nephropathy: the Gonryo study

To examine the clinical significance of hypertensive nephropathy (HN) among non-diabetic chronic kidney disease (CKD) patients. The study comprised 2692 CKD patients recruited from 11 outpatient nephrology clinics; these included 1306 patients with primary renal disease (PRD), 458 patients with HN, 283 patients with diabetic nephropathy (DN) and 645 patients with other nephropathies (ONs). All patients fulfilled the criteria of CKD, with a persistent low estimated glomerular filtration rate (eGFR) <60 ml min(-1) per 1.73 m(2) or proteinuria as determined by a urine dipstick test. The risk factors for cardiovascular disease (CVD), such as ischemic heart disease, congestive heart failure and stroke; all-cause mortality; and progression to end-stage renal failure (dialysis induction) were analyzed using a Cox proportional hazards model in each group. During a mean follow-up period of 22.6 months from recruitment, 100 patients were lost to follow-up and 192 patients began chronic dialysis therapy. A total of 115 CVD events occurred (stroke in 37 cases), and 44 patients died. Regarding CVD events and death, there were significant differences in the hazard ratios (HRs) for the groups of patients with different underlying renal diseases as determined by both univariate and multivariate analysis adjusted for confounding factors including estimated glomerular filtration rate: PRD, 1.0 (reference); HN, 3.33 (95% confidence interval, 1.82-6.09); DN, 5.93 (2.80-12.52); and ON, 2.22 (1.22-4.05). However, there were no differences in the hazard ratio for dialysis induction for the groups of patients with different underlying renal diseases. HN is associated with an increased risk of CVD events and death among non-diabetic CKD patients, which highlights the clinical significance of HN.

Role of chronic kidney disease in cardiovascular disease: are we different from others?

The incidence and prevalence of chronic dialysis patients in Japan is increasing linearly and is currently as high as 300 and 2300 per million population, respectively. The incidence of end-stage renal disease is closely related to that of chronic dialysis; findings which are captured in detail in the Japanese Society for Dialysis Therapy registry. Life expectancy of dialysis patients is poor compared to the age- and sex-matched general population, and is equivalent to that of an 80-year-old man or an 87-year-old woman, i.e., dialysis patients seem 15-18 years older than their actual age. Cardiac death is the leading cause of death; however, death due to stroke and acute myocardial infarction is decreasing. The annual mortality rate is 6.5% among the dialysis population. For the past 10 years, the mortality risk has remained high despite the avoidance of blood transfusions by the administration of erythropoiesis-stimulating agents, the use of renin-angiotensin system inhibitors, and improvements in general medical care. Several studies have confirmed the significance of chronic kidney disease (CKD) on the development of cardiovascular disease (CVD) and mortality; the lower the estimated glomerular filtration rate (eGFR), the higher the incidence of CVD. The cut-off levels for eGFR are not yet clear. CKD is an important predictor of CVD in Japan, similar to other parts of the world. Strategies for early detection of CKD are needed because, in many cases, CKD remains asymptomatic until late stages. Timely treatment for CKD is necessary to minimize costs for unnecessary care and testing. Unless CDK is properly managed, it will not be possible to maintain quality and longevity of life. The Japanese population is rapidly aging and will have the largest proportion of elderly people in the world. A systematic strategy for managing CKD patients is warranted.

Analysis of cardiovascular disease in Chinese inpatients with chronic kidney disease

OBJECTIVE

To investigate the prevalence of cardiovascular disease (CVD) in a Chinese patient population with different stages of chronic kidney disease (CKD).

METHODS

Six hundred and two CKD patients who were hospitalized in Ruijin Hospital between Jan. 2004 and Jan. 2006 were selected. Patients' medical histories and the results of laboratory tests were reviewed.

RESULTS

The prevalence of CVD in 602 patients with CKD stages 1 to 5 was 1.28%, 17.24%, 22.86%, 33.33%, 56.2% respectively. The prevalence of CVD in CKD stage 5 patients with dialysis was 78.51%. In all the patients, the prevalence of coronary artery disease (CAD), left ventricular hypertrophy (LVH), and congestive heart failure (CHF) was 8.64% (52/602), 26% (154/602), and 13% (78/602), respectively. Regarding co-morbidities of CVD, 34.52% of patients had 2 or more of the above abnormalities. The prevalence of CAD in patients with CKD stages 1 to 5 respectively was 1.28%, 5.75%, 7.86%, 10.26%, 12.33%;LVH was 0%, 11.49%, 16.43%, 29.49%, 44.75%; and CHF was 0%, 3.45%, 3.57%, 8.97%, 28.77%.

CONCLUSION

The occurrence of CVD started from CKD stage 1 and increased with the progression of CKD. The screening and prevention of CVD should begin at CKD stage 1.

Chronic Kidney Disease Japan Cohort study: baseline characteristics and factors associated with causative diseases and renal function

BACKGROUND

Prevalence of chronic kidney disease (CKD) is estimated to be 13.3 million in Japan, but patient characteristics during the predialysis period (CKD stages 3-5) are not well studied.

METHODS

We established the Chronic Kidney Disease Japan Cohort (CKD-JAC) to study the incidence of cardiovascular disease (CVD), end-stage renal disease (ESRD), and all-cause mortality in predialysis patients treated by nephrologists for 4 years. The inclusion criteria were (1) Japanese and Asian patients living in Japan, (2) age 20-75 years, and (3) estimated glomerular filtration rate (eGFR) 10-59 ml/min/1.73 m(2).

RESULTS

We analyzed 2977 participants for baseline characteristics. Mean eGFR was 28.6 ± 11.8 ml/min/1.73 m(2), and mean albuminuria was 976 ± 1340 mg/g Cr. In our study, 91.9% of participants had hypertension, but it was well controlled (131/76 mmHg). Angiotensin converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) were used by most participants. Less than 15% of participants had history of ischemic heart disease, and 11.5% had history of stroke. Heart failure and arteriosclerosis obliterans were present in 3.9% and 3.6% of patients, respectively. Indicators of arteriosclerosis, higher pulse wave velocity (PWV), and high pulse pressure were associated with diabetes and particularly with diabetic nephropathy. Patients included due to glomerulonephritis seemed to be at low risk for atherosclerosis and also to show lower levels of hypertension.

CONCLUSIONS

The difference between causative diseases is associated with different comorbidity and level of arteriosclerosis. Future analysis of the cohort will clarify whether incidence of ESRD and CVD differs among causative diseases.