Risk of end-stage renal disease in Japanese patients with chronic kidney disease increases proportionately to decline in estimated glomerular filtration rate

Effect of rehabilitation on renal outcomes after acute kidney injury associated with cardiovascular disease: a retrospective analysis

BACKGROUND

Acute kidney injury (AKI) incidence is extremely high worldwide, and patients who develop AKI are at increased risk of developing chronic kidney disease (CKD), CKD progression, and end-stage kidney disease (ESKD). However, there is no established treatment strategy for AKI. Based on the idea that exercise has a stabilizing effect on hemodynamics, we hypothesized that rehabilitation would have beneficial renal outcomes in patients with AKI associated with cardiovascular disease. Therefore, the purpose of this study was to determine whether rehabilitation can stabilize hemodynamics and positively impact renal outcomes in patients with AKI associated with cardiovascular disease.

METHODS

In total, 107 patients with AKI associated with cardiovascular disease were enrolled in this single-center retrospective study and were either assigned to the exposure group (n = 36), which received rehabilitation at least once a week for at least 8 consecutive weeks, or to the control group (n = 71). Estimated glomerular filtration rate was assessed at baseline before admission, at the lowest value during hospitalization, and at 3, 12, and 24 months after enrolment. Trends over time (group × time) between the two groups were compared using generalized estimating equations. Moreover, congestive status was assessed by amino-terminal pro-B-type natriuretic peptide (NT-proBNP), and the effect of rehabilitation on congestion improvement was investigated using logistical regression analysis.

RESULTS

The time course of renal function after AKI, from baseline to each of the three timepoints suggested significant differences between the two groups (p < 0.01). However, there was no significant difference between the two groups at any time point in terms of percentage of patients who experienced a 40% estimated glomerular filtration rate reduction from that at baseline. The proportion of patients with improved congestion was significantly higher in the exposure group compared with that in the control group (p = 0.018). Logistic regression analysis showed that rehabilitation was significantly associated with improved congestion (p = 0.021, OR: 0.260, 95%CI: 0.083-0.815).

CONCLUSION

Our results suggest that rehabilitation in patients with AKI associated with cardiovascular disease correlates with an improvement in congestion and may have a positive effect on the course of renal function.

Pulse pressure modifies the association between diastolic blood pressure and decrease in kidney function: the Japan Specific Health Checkups Study

Background

Unlike systolic blood pressure (SBP), the prognostic value of diastolic blood pressure (DBP) in kidney function has not been established. We hypothesized that pulse pressure (PP), which is associated with arteriosclerosis, would affect the prognostic value of DBP.

Methods

This longitudinal study used data from the Japan Specific Health Checkups Study was conducted between 2008 and 2014. The participants were stratified into three PP subgroups (low PP ≤39, normal PP 40-59 and high PP ≥60 mmHg). The exposures of interest were SBP and DBP, and the association between SBP/DBP and kidney outcomes (30% decline in the estimated glomerular filtration rate from baseline) was examined in each PP subgroup using a Cox proportional hazards model.

Results

Among 725 022 participants, 20 414 (2.8%) developed kidney outcomes during a median follow-up period of 34.6 months. Higher SBP was consistently associated with a higher incidence of kidney outcome in all PP subgroups. Although DBP had a positive linear association with the incidence of kidney outcome in low- and normal-PP subgroups, both lower (≤60 mmHg) and higher (≥101 mmHg) DBP were associated with a higher incidence of kidney outcome in the high-PP subgroup, with a U-shaped curve. Hazard ratios (95% confidence intervals) of ≤60 mmHg (reference: 61-80 mmHg in normal-PP subgroup) and ≥101 mmHg were 1.26 (1.15-1.38) and 1.86 (1.62-2.14), respectively.

Conclusions

In this large population-based cohort, DBP was differently associated with kidney outcome by PP level; lower DBP was significantly associated with a higher incidence of kidney outcome in the high-PP subgroup but not in the low- and normal-PP subgroups.

Calcification Propensity (T50) Predicts a Rapid Decline of Renal Function in Kidney Transplant Recipients

BACKGROUND

Serum creatinine level, proteinuria, and interstitial fibrosis are predictive of renal prognosis. Fractional excretion of phosphate (FEP)/FGF23 ratio, tubular reabsorption of phosphate (TRP), serum calcification propensity (T50), and Klotho's serum level are emerging as determinants of poor kidney outcomes in CKD patients. We aimed at analysing the use of FGF23, FEP/FGF23, TRP, T50, and Klotho in predicting the rapid decline of renal function in kidney allograft recipients.

METHODS

We included 103 kidney allograft recipients in a retrospective study with a prospective follow-up of 4 years. We analysed the predictive values of FGF23, FEP/FGF23, TRP, T50, and Klotho for a rapid decline of renal function defined as a drop of eGFR > 30%.

RESULTS

During a follow-up of 4 years, 23 patients displayed a rapid decline of renal function. Tertile of FGF23 (p value = 0.17), FEP/FGF23 (p value = 0.78), TRP (p value = 0.62) and Klotho (p value = 0.31) were not associated with an increased risk of rapid decline of renal function in kidney transplant recipients. The lower tertile of T50 was significantly associated with eGFR decline >30% with a hazard ratio of 3.86 (p = 0.048) and remained significant in multivariable analysis.

CONCLUSION

T50 showed a strong association with a rapid decline of renal function in kidney allograft patients. This study underlines its role as an independent biomarker of loss of kidney function. We found no association between other phosphocalcic markers, such as FGF23, FEP/FGF23, TRP and Klotho, with a rapid decline of renal function in kidney allograft recipients.

Characterization of baseline clinical factors associated with incident worsening kidney function in patients with non-valvular atrial fibrillation: the Hokuriku-Plus AF Registry

Evidence suggests that atrial fibrillation (AF) could increase the risk of worsening kidney function (WKF) which is linked to an increased risk of stroke, bleeding, and death in AF patients. However, limited data exist regarding the factors that could lead to WKF in these patients. Therefore, we sought to identify the potential factors associated with the development of WKF in patients with non-valvular AF (NVAF). We analyzed prospectively recruited 1122 NVAF patients [men 71.9%, median age 73.0 years (interquartile range: 66.0-79.0)] with a baseline estimated glomerular filtration rate (eGFR) ≥ 15 mL/min/1.73 m² from the Hokuriku-Plus AF Registry. The primary outcome was incident WKF, defined as the %eGFR change from the baseline ≥ 30% during the follow-up period. We evaluated the association between baseline variables and incident WKF using univariate and multivariate Cox proportional hazard models. We also evaluated the non-linear association between the identified factors and incident WKF. During a median follow-up period of 3.0 years (interquartile range: 2.7-3.3), incident WKF was observed in 108 patients (32.6 per 1000 person-years). Compared to the patients without incident WKF, the patients with incident WKF were older and had a higher prevalence of heart failure (HF), diabetes mellitus (DM), and vascular disease at baseline. Those who experienced incident WKF also had higher diastolic blood pressure, lower hemoglobin, lower eGFR, higher B-type natriuretic peptide (BNP) and used warfarin more frequently. Upon multivariate analysis, age ≥ 75 years, HF, DM, and anemia were independently associated with incident WKF. Additionally, age and hemoglobin were linearly associated with the risk of incident WKF, whereas a J- or U-shaped association was observed for HbA1c and BNP. Age ≥ 75 years, HF, DM, and anemia were associated with the development of WKF in Japanese patients with NVAF. In patients with these risk factors, a careful monitoring of the kidney function and appropriate interventions may be important when possible.

Incidence of acute kidney injury and decreased estimated glomerular filtration rate according to the site of cancer

BACKGROUND

The epidemiology of renal impairment in patients with cancer remains unclear. We aimed to clarify associations between various cancer sites and renal impairment.

METHODS

We reviewed data from 5674 patients aged ≥ 18 years receiving cancer treatment at a single hospital facility. The primary endpoints were the occurrence of acute kidney injury (AKI), a 30% decrease in the estimated glomerular filtration rate (eGFR), or death. Survival time was defined as the time from study enrolment to AKI occurrence. Kaplan-Meier and Cox proportional hazard analyses were performed.

RESULTS

Hazard ratios (HRs) for AKI occurrence and a ≥ 30% decline in eGFR were significantly higher for kidney, urinary tract, pancreatic, liver, and gallbladder cancers than for colon cancer. Compared with colon cancer, digestive tract cancer showed a significantly higher HR for AKI occurrence alone. The HRs for a ≥ 30% decline in eGFR were significantly higher for patients aged 71‒77 years or ≥ 78 years than for those aged < 68 years, and for patients with eGFR ≥ 90 mL/min/1.73 m² or 30-44 mL/min/1.73 m² than for those with eGFR = 45‒59 mL/min/1.73 m².

CONCLUSIONS

Kidney, urinary, hepatobiliary, or pancreatic cancer are associated with a higher risk of AKI development and eGFR decrease than other cancers. Renal function changes should be more closely monitored in patients with these cancers.

Association of urinary liver-type fatty acid-binding protein with renal functions and antihyperglycemic drug use in type 2 diabetic nephropathy patients

PURPOSE

In diabetic nephropathy exacerbation, a reduction in the estimated glomerular filtration rate (eGFR) without raised albuminuria or proteinuria has been frequently observed. This study aimed to clarify the clinical usefulness of urinary liver-type fatty acid-binding protein (L-FABP) in the exacerbation of diabetic nephropathy in type 2 diabetes.

METHODS

A cross-sectional study and a retrospective observational study of 227 patients with type 2 diabetes were conducted to investigate the relationship between urinary L-FABP and renal dysfunction. Changes in urinary L-FABP with or without additional administration of antihyperglycemic drugs were examined in 63 patients.

RESULTS

Baseline urinary L-FABP was significantly associated with baseline eGFR (ρ = -0.34, p < 0.001) and baseline albuminuria (ρ = 0.64, p < 0.001). In multivariate regression analysis, baseline urinary L-FABP was a significant independent factor for eGFR reduction [β = -0.348, 95% confidence interval (CI) = -0.482 to -0.214, p < 0.001]. Cox regression analysis showed that patients with a baseline urinary L-FABP above 6.5 μg/g creatinine exhibited a higher hazard ratio (HR) for the renal dysfunction surrogate end point (HR = 15.00, 95% CI 3.640-61.40, p < 0.001). In logistic regression analysis, administration of sodium glucose cotransporter-2 inhibitors was associated with a statistically significant reduction in urinary L-FABP levels, independent of changes in systolic blood pressure, glycosylated hemoglobin, and eGFR (odds ratio = 0.75, 95% CI 0.56-0.99, p = 0.04).

CONCLUSION

Urinary L-FABP may be associated with the future decrease in renal functions in type 2 diabetic nephropathy patients. Additionally, urinary L-FABP could be used as a marker of the effectiveness of diabetic nephropathy treatment.

Effect of canagliflozin on the decline of estimated glomerular filtration rate in chronic kidney disease patients with type 2 diabetes mellitus: A multicenter, randomized, double-blind, placebo-controlled, parallel-group, phase 3 study in Japan

AIMS/INTRODUCTION

The Canagliflozin and Renal Events in Diabetes with Established Nephropathy Clinical Evaluation (CREDENCE) trial has demonstrated the effects of canagliflozin on preventing clinically important kidney outcomes in patients with type 2 diabetes mellitus and chronic kidney disease; however, not many Japanese patients were included in the trial. The present study evaluated the efficacy and safety of canagliflozin in Japanese chronic kidney disease patients with type 2 diabetes mellitus.

MATERIALS AND METHODS

In this multicenter, randomized, double-blind, placebo-controlled, parallel-group, phase 3 study, chronic kidney disease patients with type 2 diabetes mellitus were randomly assigned to receive either 100 mg canagliflozin or a matching placebo once daily for 104 weeks. The primary efficacy endpoint was the incidence of a 30% decline in estimated glomerular filtration rate.

RESULTS

Overall, 308 patients were randomized to the canagliflozin (n = 154) and placebo (n = 154) groups. The incidence of a 30% decline in estimated glomerular filtration rate at Week 104 was 18.2% and 29.5%, respectively, and the point estimate of the intergroup difference (placebo - canagliflozin) was 11.3% (95% confidence interval, 1.2-21.5, P = 0.029), which was significant. The overall incidence of adverse events was similar in the two groups.

CONCLUSIONS

This study suggests that canagliflozin safely reduces the risk of end-stage renal disease in Japanese chronic kidney disease patients with type 2 diabetes mellitus.

CLINICALTRIALS

gov (NCT03436693).

Development of a machine learning-based prediction model for extremely rapid decline in estimated glomerular filtration rate in patients with chronic kidney disease: a retrospective cohort study using a large data set from a hospital in Japan

OBJECTIVES

Trajectories of estimated glomerular filtration rate (eGFR) decline vary highly among patients with chronic kidney disease (CKD). It is clinically important to identify patients who have high risk for eGFR decline. We aimed to identify clusters of patients with extremely rapid eGFR decline and develop a prediction model using a machine learning approach.

DESIGN

Retrospective single-centre cohort study.

SETTINGS

Tertiary referral university hospital in Toyoake city, Japan.

PARTICIPANTS

A total of 5657 patients with CKD with baseline eGFR of 30 mL/min/1.73 m² and eGFR decline of ≥30% within 2 years.

PRIMARY OUTCOME

Our main outcome was extremely rapid eGFR decline. To study-complicated eGFR behaviours, we first applied a variation of group-based trajectory model, which can find trajectory clusters according to the slope of eGFR decline. Our model identified high-level trajectory groups according to baseline eGFR values and simultaneous trajectory clusters. For each group, we developed prediction models that classified the steepest eGFR decline, defined as extremely rapid eGFR decline compared with others in the same group, where we used the random forest algorithm with clinical parameters.

RESULTS

Our clustering model first identified three high-level groups according to the baseline eGFR (G1, high GFR, 99.7±19.0; G2, intermediate GFR, 62.9±10.3 and G3, low GFR, 43.7±7.8); our model simultaneously found three eGFR trajectory clusters for each group, resulting in nine clusters with different slopes of eGFR decline. The areas under the curve for classifying the extremely rapid eGFR declines in the G1, G2 and G3 groups were 0.69 (95% CI, 0.63 to 0.76), 0.71 (95% CI 0.69 to 0.74) and 0.79 (95% CI 0.75 to 0.83), respectively. The random forest model identified haemoglobin, albumin and C reactive protein as important characteristics.

CONCLUSIONS

The random forest model could be useful in identifying patients with extremely rapid eGFR decline.

TRIAL REGISTRATION

UMIN 000037476; This study was registered with the UMIN Clinical Trials Registry.

Association between Serum Inorganic Phosphorus Levels and Adverse Outcomes in Chronic Kidney Disease: The Fukushima CKD Cohort Study

Objective Although an association between serum inorganic phosphorus levels and a poor prognosis has been noted in dialysis patients, these associations have been insufficiently reported in non-dialysis-dependent chronic kidney disease (NDD-CKD) patients. This study attempted to determine the association between serum inorganic phosphorus levels and adverse outcomes in Japanese NDD-CKD patients. Methods We investigated the relationships between serum inorganic phosphorus levels and adverse outcomes, such as kidney events, cardiovascular events, and all-cause death, in Japanese NDD-CKD patients using longitudinal data from the Fukushima CKD Cohort Study with a median follow-up period of 2.8 years. The study evaluated 822 patients with NDD-CKD enrolled between June 2012 and July 2014. A kidney event was defined as a combination of doubling of the baseline serum creatinine or end-stage renal disease. Cox regression was performed to analyze the relationships of the quartile of the serum inorganic phosphorus with kidney events, cardiovascular events, and all-cause death. Results The frequency of kidney events per 1,000 person-years exhibited a U-shaped distribution based on serum inorganic phosphorus levels, with these levels not significantly associated with an increased risk of cardiovascular events and all-cause death. A multivariable Cox regression analysis showed an increased risk of kidney events for the highest quartile of the serum inorganic phosphorus levels (≥3.7 mg/dL) versus the second quartile (2.9-3.2 mg/dL, hazard ratio, 3.30; 95% confidence interval, 1.50-7.28; p=0.003). There were no significant associations between the serum calcium levels and adverse outcomes. Conclusion Serum inorganic phosphorus levels were associated with an increased risk of CKD progression in Japanese NDD-CKD patients.

Evaluation of the Effect of Topiroxostat on Renal Function in Patients with Hyperuricemia: STOP-C Study, a Retrospective Observational Cohort Study

Background

Serum uric acid-lowering therapy is associated with maintaining renal function.

Objective

We aimed to retrospectively evaluate renal function and serum uric acid in patients with hyperuricemia who received topiroxostat for over a year.

Methods

Medical records of patients from 1 January, 2015 to 31 October, 2019 in our hospital were used. From the medical records, data of 100 patients with hyperuricemia treated with topiroxostat were extracted (67:33 male:female). The primary endpoints were changes in serum creatinine level and estimated glomerular filtration rate at 12 months after topiroxostat administration. The secondary endpoints were changes in serum creatinine, serum uric acid, and estimated glomerular filtration rate before and after topiroxostat administration.

Results

The study mainly involved elderly individuals (77.2 ± 9.5 years). Forty-four patients administered uric acid-lowering drugs were switched to topiroxostat. After 12 months, the serum creatinine level and estimated glomerular filtration rate showed no significant changes from baseline; however, the serum uric acid level significantly decreased. The estimated glomerular filtration rate significantly decreased during the 6 months before topiroxostat administration (p < 0.001), but showed no significant change at 6 months after topiroxostat administration (p = 0.849).

Conclusions

This study revealed that topiroxostat use not only reduced the serum uric acid level but also maintained renal function in elderly patients with hyperuricemia in daily clinical practice.

OUP accepted manuscript

Background

Evidence linking chronic kidney disease (CKD) and sleep duration is inconsistent. This study examined whether sleep duration is associated with a long-term risk of kidney function decline.

Methods

This retrospective, longitudinal cohort study included 82 001 participants who visited a primary care centre in Japan. Participants were categorized into CKD risk groups and sleep duration categories according to their self-reported average nightly sleep duration. The relationship between average nightly sleep duration and the incidence of composite renal outcome comprised a ≥40% reduction in estimated glomerular filtration rate (eGFR) from baseline and a decline in eGFR to <15 mL/min/1.73 m² was evaluated.

Results

The mean age and eGFR (±standard deviation) of the patient cohort were 45.8 (±12.4) years and 81.8 (±15.4) mL/min/1.73 m², respectively. A total of 41 891 participants (51.1%) were women. During the median follow-up of 5.1 years [interquartile range 2.2–9.6], 4214 (5.1%) participants achieved the composite renal outcome. Only the long and very long sleep durations (≥8 h/night) were associated with an increased incidence of the composite renal outcome compared with the reference duration (7 h/night) [adjusted odds ratio (OR) 1.22 and 1.44; 95% confidence interval (CI) 1.09–1.36 and 1.13–1.84, for long and very long sleep durations, respectively]. Furthermore, this association was significant for both long and very long sleep durations in the low CKD risk group but only for long sleep duration in the intermediate CKD risk group. The results of the sex-specific analysis showed that men had a decreased risk of achieving the composite renal outcome (OR 0.91; 95% CI 0.79–1.06), while there was an increased risk for women (OR 1.14; 95% CI 1.02–1.28).

Conclusions

Average sleep durations ≥8 h/night were associated with an increased incidence of poor renal outcomes over time. However, a longitudinal cohort study is required to confirm whether sleep duration can prevent poor renal outcomes.

Comparison of administration of single- and triple-course steroid pulse therapy combined with tonsillectomy for immunoglobulin A nephropathy

Immunoglobulin A nephropathy (IgAN) is a form of chronic glomerulonephritis that can cause end-stage renal disease. Recently, tonsillectomy combined with corticosteroid pulse (TSP) has been shown to be effective for achieving clinical remission and favorable renal outcome in patients with IgAN. However, the standard regimen of corticosteroid use in TSP has not been established. Herein, we compared the effect of single- or triple-course steroid pulse therapy combined with tonsillectomy in patients with IgAN.This retrospective, observational cohort study included 122 patients with IgAN enrolled from January 2004 to December 2018 at 2 independent institutions. We divided the patients into 2 groups; single-course (TSP1: n = 70) and triple-course (TSP3: n = 52) of corticosteroid pulse therapy (1 course comprised 3 consecutive days' infusion of 0.5 g methylprednisolone) combined with tonsillectomy. The primary outcome for renal survival was defined as the first occurrence of ≧30% decrease in estimated glomerular filtration rate from baseline. Secondary outcomes included the incidence of clinical remission and recurrence of the disease.Regarding clinical parameters and findings at baseline, there were no significant differences between the 2 groups. The 8-years renal survival in the 2 groups was not significantly different according to Kaplan-Meier curves (TSP1; 82.5% vs TSP3; 69.2%, log-rank test P = .39). The cumulative incidence rates of remission of hematuria (94.4% vs 85.4%, P = .56) and clinical remission (85.0% vs 64.8%, P = .07) were comparable in both groups, while those of proteinuria showed higher rates in TSP1 than TSP3 (88.4% vs 65.4%, P = .02). The cumulative incidence of relapse of hematuria (5.6% vs 2.3%, P = .42) and proteinuria (7.1% vs 3.3%, P = .41) showed no significant differences in the 2 groups. Cox regression analyses showed that the number of courses of corticosteroid pulse therapy was not significantly associated with renal outcome (TSP1 vs TSP3; Hazard ratios 0.69, 95% confidence intervals 0.29-1.64, P = .39).The effect of single-course corticosteroid pulse therapy is not statistically, significantly different from triple-course in TSP protocol for improving renal outcome and preventing relapse in patients with IgAN. Single-course corticosteroid pulse therapy may become a treatment option for patients with IgAN.

Estimating the causal effect of transient anemia status on renal and cardiovascular outcomes in community-dwelling patients in Japan at the beginning of impaired renal function using marginal structural modeling

Background

Anemia status may be transient. Causal associations between changes in anemia status over time and adverse outcome development are not well characterized in community-dwelling subjects at the beginning of impaired kidney function.

Methods

This retrospective cohort study used annual health checkup and medical and pharmacy claims data from the JMDC between January 2005 and June 2019. Community-dwelling subjects in Japan with a pre-index estimated glomerular filtration rate (eGFR) ≥ 60 mL/min/1.73 m² followed by a subsequent eGFR < 60 mL/min/1.73 m² (index) were included. The composite renal outcome was ≥ 30% eGFR reduction over 3 years from baseline, serum creatinine doubling, progression to chronic dialysis, kidney transplantation, or eGFR < 15 mL/min/1.73 m². The composite cardiovascular outcome was fatal and non-fatal unstable angina, myocardial infarction, heart failure, or cerebrovascular event. Time-dependent anemia risk was evaluated using Breslow’s estimator and marginal structural Cox models (MSM).

Results

In 32,870 included subjects, 1,396 had anemia at baseline. Adverse outcome incidence was higher in the baseline anemic group, but absolute differences in renal and cardiovascular outcomes between groups were diminished after adjusting for baseline characteristics. In MSM, time-dependent anemia status was associated with higher risk of renal (hazard ratio [95% confidence interval]; 2.6 [1.7–3.8]) and cardiovascular (1.6 [1.2–2.2]) outcomes and mortality (2.8 [1.8–4.3]). Absolute differences in survival probabilities were retained over time but were clinically marginal (1.1–2.7% over 6 years).

Conclusions

Even in subjects at the very early stage of impaired kidney function, early detection and treatment of anemia may help reduce the development of negative sequelae.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10157-021-02137-1.

Focal segmental glomerulosclerosis histologic variants and renal outcomes based on nephrotic syndrome, immunosuppression, and proteinuria remission

BACKGROUND

The associations of focal segmental glomerulosclerosis (FSGS) histologic variants with renal outcomes have rarely been investigated comprehensively by clinically relevant subgroups in this modern age.

METHODS

Data on 304 (173 nephrotic and 131 non-nephrotic) patients with biopsy-confirmed FSGS from 2010 to 2013 were analyzed using the Japanese nationwide renal biopsy registry. The primary outcome was a composite of a 30% decline in estimated glomerular filtration rate or progression to end stage kidney disease 5 years from the biopsy. We compared outcomes of FSGS variants according to the Columbia classification using survival analyses. Subgroup analyses were performed based on nephrotic syndrome (NS), immunosuppression, and proteinuria remission (PR, proteinuria <0.3 g/day) during follow-up. Additionally, associations of NS, immunosuppression, and PR with outcomes were examined for each variant.

RESULTS

The distribution of variants was 48% (n = 145) FSGS not otherwise specified (NOS), 19% (n = 57) tip, 15% (n = 47) perihilar, 13% (n = 40) cellular, and 5% (n = 15) collapsing. The outcome event occurred in 87 patients (29%). No significant differences in the outcome were found among the variants. Subgroup analyses yielded similar results. However, there was a trend toward improved outcome in patients with PR irrespective of variants (hazard ratio adjusted for histologic variant and potential confounders [adjusted HR]: 0.19 [95% confidence interval (CI), 0.10-0.34]). NS was marginally associated with better outcome compared with non-NS (adjusted HR: 0.50 [95% CI, 0.25-1.01].

CONCLUSIONS

FSGS variants alone might not have significant impacts on the renal outcome after 5 years, while PR could be predictive of improved renal prognosis for any variant. Specific strategies and interventions to achieve PR for each variant should be implemented for better renal outcomes.

Association of blood pressure and renal outcome in patients with chronic kidney disease; a post hoc analysis of FROM-J study

It is well-known that hypertension exacerbates chronic kidney disease (CKD) progression, however, the optimal target blood pressure (BP) level in patients with CKD remains unclear. This study aimed to assess the optimal BP level for preventing CKD progression. The risk of renal outcome among different BP categories at baseline as well as 1 year after, were evaluated using individual CKD patient data aged between 40 and 74 years from FROM-J [Frontier of Renal Outcome Modifications in Japan] study. The renal outcome was defined as ≥ 40% reduction in estimated glomerular filtration rate to < 60 mL/min/1.73 m², or a diagnosis of end stage renal disease. Regarding baseline BP, the group of systolic BP (SBP) 120-129 mmHg had the lowest risk of the renal outcome, which increased more than 60% in SBP ≥ 130 mmHg group. A significant increase in the renal outcome was found only in the group of diastolic BP ≥ 90 mmHg. The group of BP < 130/80 mmHg had a benefit for lowering the risk regardless of the presence of proteinuria, and it significantly reduced the risk in patients with proteinuria. Achieving SBP level < 130 mmHg after one year resulted in a 42% risk reduction in patients with SBP level ≥ 130 mmHg at baseline. Targeting SBP level < 130 mmHg would be associated with the preferable renal outcome.Clinical Trial Registration-URL: https://www.umin.ac.jp/ctr/ . Unique identifier: UMIN000001159 (16/05/2008).

Association between uric acid lowering and renal function progression: a longitudinal study

Background

This study aimed to explore the association between uric acid lowering and renal function.

Materials and Methods

We conducted a population-based cohort study with 1,534 subjects for 4 years from 2012 to 2016. The population was divided into four groups according to the interquartile range of changes in serum uric acid with quartile 1 representing lower quarter. Renal function decline was defined as eGFR decreased more than 10% from baseline in 2016. Renal function improvement was defined as eGFR increased more than 10% from baseline in 2016. Cox regression analysis was used to calculate the hazard ratio (HR) and 95% confidence interval (CI).

Results

In the adjusted Cox regression models, compared to quartile 4, quartile 1 (HR = 0.64, 95% CI [0.49–0.85]), quartile 2 (HR = 0.65, 95% CI [0.50–0.84]) and quartile 3 (HR = 0.75, 95% CI [0.58–0.96]) have reduced risk of renal function decline. An increasing hazard ratio of renal function improvement was shown in quartile 1 (HR = 2.27, 95% CI [1.45–3.57]) and quartile 2 (HR = 1.78, 95% CI [1.17–2.69]) compared with quartile 4.

Conclusions

Uric acid lowering is associated with changes in renal function. The management of serum uric acid should receive attention in clinical practice and is supposed to be part of the treatment of chronic kidney disease.

Sex Differences in Time-Series Changes in Pseudo-R2 Values Regarding Hyperuricemia in Relation to the Kidney Prognosis

Studies on sex differences in time-series changes in pseudo-R² values regarding hyperuricemia (HU) in relation to the kidney prognosis among patients with chronic kidney disease (CKD) are scant. The kidney prognosis was evaluated in 200 patients with CKD (median follow-up, 12.3 years). Survival analyses and logistic regression analyses were conducted, generating time-series pseudo-R² values. We used four definitions of HU according to serum uric acid (SUA) levels (HU6, SUA ≥ 6.0 mg/dL; HU7, SUA ≥ 7.0 mg/dL; HU8, SUA ≥ 8.0 mg/dL) and antihyperuricemic agent use to calculate the mean and percentage of the change in pseudo-R² values from the 6th year until the end of the study (6Y–End Mean and 6Y–End Change, respectively). The multivariable Cox regression analysis showed that HU7 was significantly associated with kidney outcomes. When stratified by sex, the 6Y–End Mean was clearly higher in women than in men for all HU definitions, with the highest value (0.1755) obtained for HU7 in women. The pseudo-R² values for HU6 in women showed an increasing pattern, with a 6Y–End Change of 11.4%/year. Thus, it may be clinically meaningful to consider sex differences in the time-series pseudo-R² values regarding HU and kidney outcomes.

Visceral to subcutaneous fat ratio as an indicator of a ≥30% eGFR decline in chronic kidney disease

Whether the visceral-to-subcutaneous fat ratio (V/S ratio) is associated with renal prognosis in patients with chronic kidney disease (CKD) remains unclear. Furthermore, little is known about the effect of sex and the absolute amount of visceral fat accumulation such as visceral fat area (VFA) ≥100 cm² on the V/S ratio in relation to renal prognosis. In this study, 200 patients with CKD were evaluated for renal prognosis. Survival analyses and logistic regression analyses were conducted, generating time-series pseudo-R² values. The mean and percent change of the pseudo-R² values from the 6^th year to the 10^th year (6Y–10Y Mean and 6Y–10Y Change, respectively) were calculated for determining the cut-off points for the medium-term renal prognosis. Multivariate Cox regression analysis revealed that the V/S ratio was significantly associated with renal outcomes and that the VFA category (VFA ≥ 100 cm²) had significant interactions with the V/S ratio regarding renal prognosis. The hazard ratio (HR) of the V/S ratio was higher in the sub-cohort of VFA < 100 cm² than in the sub-cohort of VFA ≥ 100 cm² (HR: 6.42 vs. 1.00). Regarding sex differences, a strong association was noted between the V/S ratio and renal prognosis in women but not in men (HR: 2.40 vs. 1.10). On the other hand, 6Y–10Y Mean of the pseudo-R² values indicated differences in the cut-off points of the V/S ratio between men and women (V/S ratio: 0.75 vs. 0.5). Our findings indicate that it may be clinically meaningful to consider the differences in sex and the amount of VFA ≥100 cm² for the V/S ratio in relation to renal outcomes in patients with CKD. The 6Y–10Y Mean of the pseudo-R² values contributed to determining the cut-off points of the V/S ratio according to the sex difference.

Increasing tendency of urine protein is a risk factor for rapid eGFR decline in patients with CKD: A machine learning-based prediction model by using a big database

Artificial intelligence is increasingly being adopted in medical fields to predict various outcomes. In particular, chronic kidney disease (CKD) is problematic because it often progresses to end-stage kidney disease. However, the trajectories of kidney function depend on individual patients. In this study, we propose a machine learning-based model to predict the rapid decline in kidney function among CKD patients by using a big hospital database constructed from the information of 118,584 patients derived from the electronic medical records system. The database included the estimated glomerular filtration rate (eGFR) of each patient, recorded at least twice over a period of 90 days. The data of 19,894 patients (16.8%) were observed to satisfy the CKD criteria. We characterized the rapid decline of kidney function by a decline of 30% or more in the eGFR within a period of two years and classified the available patients into two groups—those exhibiting rapid eGFR decline and those exhibiting non-rapid eGFR decline. Following this, we constructed predictive models based on two machine learning algorithms. Longitudinal laboratory data including urine protein, blood pressure, and hemoglobin were used as covariates. We used longitudinal statistics with a baseline corresponding to 90-, 180-, and 360-day windows prior to the baseline point. The longitudinal statistics included the exponentially smoothed average (ESA), where the weight was defined to be 0.9*(t/b), where t denotes the number of days prior to the baseline point and b denotes the decay parameter. In this study, b was taken to be 7 (7-day ESA). We used logistic regression (LR) and random forest (RF) algorithms based on Python code with scikit-learn library (https://scikit-learn.org/) for model creation. The areas under the curve for LR and RF were 0.71 and 0.73, respectively. The 7-day ESA of urine protein ranked within the first two places in terms of importance according to both models. Further, other features related to urine protein were likely to rank higher than the rest. The LR and RF models revealed that the degree of urine protein, especially if it exhibited an increasing tendency, served as a prominent risk factor associated with rapid eGFR decline.

Increased Urinary Liver-Type Fatty Acid-Binding Protein Level Predicts Major Adverse Cardiovascular Events in Patients With Hypertension

BACKGROUND

Urinary liver-type fatty acid-binding protein (L-FABP) has been known as a potential biomarker for acute kidney injury. It has also been suggested to have an effective predictive value for cardiovascular mortality in patients with diabetes or critically ill condition. Therefore, this study aimed to examine the ability of urinary L-FABP in predicting mid-term cardiovascular morbidity and mortality in patients with hypertension.

METHODS

Urinary L-FABP levels in stable outpatients without diabetes who were treated with antihypertensive drugs were measured, and a 5-year follow-up was planned. The primary end-point was a combination of acute heart failure requiring hospitalization, myocardial infarction, stroke, and cardiovascular death. The secondary end-point was kidney disease progression defined as a relative decline in the estimated glomerular filtration rate of ≥30% from the baseline.

RESULTS

A total of 197 patients were recruited. Primary and secondary end-points occurred in 24 (12.2%) and 42 (21.3%) patients, respectively, during a median follow-up of 5.7 years. Patients with urinary L-FABP levels higher than the upper limit (8.4 µg/g creatinine) were more likely to reach the primary (30.43% vs. 9.77%; P = 0.003) and secondary end-points (56.52% vs. 16.67%; P < 0.001) than those with urinary L-FABP levels within the normal limits. Urinary L-FABP level was independently associated with both primary (hazard ratio (HR) 1.21; P = 0.03) and secondary end-points (HR 1.19; P = 0.02).

CONCLUSIONS

This study demonstrated that increased urinary L-FABP levels may predict adverse cardiovascular events and renal dysfunction progression even among stable nondiabetic patients with hypertension.

Comparison of a Significant Decline in the Glomerular Filtration Rate between Ileal Conduit and Ileal Neobladder Urinary Diversions after Radical Cystectomy: A Propensity Score-Matched Analysis

Urinary diversion after radical cystectomy is associated with a risk of renal function impairment. A significant decline in the glomerular filtration rate (GFR) (i.e., a ≥30% decline in baseline GFR after 12 months) is associated with long-term renal function impairment. We compared the significant GFR decline between ileal conduit and ileal neobladder urinary diversions 12 months after radical cystectomy. We retrospectively included radical cystectomy patients. Propensity score-matched analysis was performed. The primary outcome was the incidence of a significant GFR decline in ileal conduit urinary diversion (ileal conduit group) and ileal neobladder urinary diversion (ileal neobladder group) 12 months after radical cystectomy. The secondary outcomes were the change of GFR and the incidence of end-stage renal disease (ESRD) in the two groups. After propensity score matching, the ileal conduit and neobladder groups had 117 patients each. The incidence of a significant GFR decline was not significantly different between ileal conduit and ileal neobladder groups (12.0% vs. 13.7%, p = 0.845). The change of GFR and ESRD incidence were not significantly different between the two groups (−8.4% vs. −9.7%, p = 0.480; 4.3% vs. 5.1%, p > 0.999, respectively). These results can provide important information on appropriate selection of the urinary diversion type in radical cystectomy.

The Clinical Course of Acute Kidney Disease after Cardiac Surgery: A Retrospective Observational Study

Acute kidney disease (AKD), or renal dysfunction persisting >7 days after an initiating event of acute kidney injury, is a rising concern. This study aimed to elucidate the clinical course of AKD after cardiac surgery with data on post-cardiac surgery patients admitted to intensive care units (ICU) at 18 Japanese hospitals during 2012–2014. Using multivariable logistic models, we evaluated the association of AKD with 90-day mortality and the 50% eGFR decline during 2-year follow-up compared to eGFR at 90 days. AKD was defined as an elevation in serum creatinine to at least 1.5-fold from baseline in >7 days after ICU admission. Of the 3,605 eligible patients undergoing cardiac surgery, 403 patients (11.2%) had AKD. Multivariable analysis revealed that the adjusted odds ratio (OR) of AKD for 90-day mortality was 63.0 (95% confidence interval [CI], 27.9–180.6). In addition, the adjusted OR of AKD for 50% eGFR decline was 3.56 (95% CI, 2.24–5.57) among hospital survivors. In conclusion, AKD after cardiac surgery was associated with higher 90-day mortality and renal function decline after hospital discharge.

High-normal albuminuria is strongly associated with incident chronic kidney disease in a nondiabetic population with normal range of albuminuria and normal kidney function

BACKGROUND

Albuminuria and estimated glomerular filtration rate (eGFR) are clinically measured to evaluate the severity of chronic kidney disease (CKD). The aim of our study was to clarify the association between clinical parameters, including albuminuria and eGFR, and the risk of incident CKD in a nondiabetic population with normal range of albuminuria and eGFR.

METHODS

A 10-year follow-up, retrospective cohort study involving 317 Japanese men (mean age, 42 years) with eGFR ≥ 90 mL/min/1.73 m² and urine albumin-to-creatinine ratio (UACR) < 30 mg/gCr was performed. Participants were free of diabetes mellitus. Multivariate logistic regression approaches were used to assess independent predictors of the incidence of CKD.

RESULTS

Twenty-nine (9%) participants developed CKD (eGFR < 60 mL/min/1.73 m² and/or UACR ≥ 30 mg/gCr) through 10 years of follow-up. At the baseline examination, age, blood pressure, UACR, and eGFR were higher in participants who developed CKD than in those without CKD. After adjustment for confounders, high-normal albuminuria (P < 0.001) and hypertension (P = 0.045) were associated with an increased incidence of CKD. From receiver-operating characteristic curves, UACR ≥ 7.0 mg/gCr was defined as high-normal albuminuria. Logistic regression analysis also showed that, in addition to presence of hypertension, UACR ≥ 7.0 mg/gCr was identified as an independent risk of incident CKD within 10 years after adjustment for age, body mass index, smoking status, and dyslipidemia [UACR: odds ratio (OR) 17.36 (95% CI 6.16-48.93, P < 0.001)].

CONCLUSION

High-normal albuminuria and hypertension are associated with incident CKD in a nondiabetic population with normal-range UACR and eGFR.

Keap1/Nrf2/ARE signaling unfolds therapeutic targets for redox imbalanced-mediated diseases and diabetic nephropathy

Hyperglycemia/oxidative stress has been implicated in the initiation and progression of diabetic complications while the components of Keap1/Nrf2/ARE signaling are being exploited as therapeutic targets for the treatment/management of these pathologies. Antioxidant agents like drugs, nutraceuticals and pure compounds that target the proteins of this pathway and their downstream genes hold the therapeutic strength to put the progression of this disease at bay. Here, we elucidate how the modulation of Keap1/Nrf2/ARE had been exploited for the treatment/management of end-stage diabetic kidney complication (diabetic nephropathy) by looking into (1) Nrf2 nuclear translocation and phosphorylation by some protein kinases at specific amino acid sequences and (2) Keap1 downregulation/Keap1-Nrf2 protein-protein inhibition (PPI) as potential therapeutic mechanisms exploited by Nrf2 activators for the modulation of diabetic nephropathy biomarkers (Collagen IV, Laminin, TGF-β1 and Fibronectin) that ultimately lead to the amelioration of this disease progression. Furthermore, we brought to limelight the relationship between diabetic nephropathy and Keap1/Nrf2/ARE and finally elucidate how the modulation of this signaling pathway could be further explored to create novel therapeutic milestones.

Prediction of presepsin concentrations through commensurate decline in kidney function in the elderly

BACKGROUND

Presepsin is a useful biomarker to diagnose sepsis. However, the correlation between plasma presepsin concentrations and kidney function in the elderly with chronic kidney disease (CKD) remains to be elucidated. We determined whether plasma presepsin concentrations were influenced by kidney function decline in the elderly.

METHODS

One hundred seventy outpatients with CKD aged ≥65 y were enrolled. Plasma presepsin concentrations were measured using immunoassay analysis. The relationship between plasma presepsin concentration and kidney function was assessed.

RESULTS

The median age of patients of this cohort was 778 (72-85) y and the mean estimated glomerular filtration rate was 51.8 ± 28.1 ml/min/1.73 m². Plasma presepsin concentrations in those with CKD G4-G5 (362 pg/ml [273-553]) were significantly higher than in those with CKD G1-G2 (111 pg/ml [91-113]) and CKD G3 (145 pg/ml [124-205]) (p < 0.001, p < 0.001, respectively). A high correlation between plasma presepsin concentrations and kidney function was observed (R² = 0.733, p < 0.001). Even after adjusting for confounders, plasma presepsin concentrations were independently associated with kidney function.

CONCLUSIONS

Increases in plasma presepsin concentrations were exponentially correlated to kidney function decline in the elderly with CKD.

Relative hypophosphatemia early after transplantation is a predictor of good kidney graft function

BACKGROUND

Phosphate level is a potent independent risk factor for cardiovascular disease and mortality in patients with chronic kidney disease. The association between hypophosphatemia and kidney function in kidney transplant patients is uncertain.

METHODS

In total, 90 kidney transplant recipients were divided into two groups: one group of patients with hypophosphatemia and the other group without hypophosphatemia. The recipients with hypophosphatemia were identified as having less than or equal to the lowest quartile of serum phosphate levels at 1-, 3-, and 12-month post-transplant. The cumulative kidney survival rates were calculated for each group using the Kaplan-Meier method, and the adjusted hazard ratio (HR) was calculated using the Cox regression model.

RESULTS

The mean age of patients was 47 years and the median follow-up period was 58 months. During the follow-up period, the following results were demonstrated in 90 transplant patients: graft loss (n = 6), mortality (n = 3). According to the Kaplan-Meier analysis results, the patients with hypophosphatemia demonstrated a significantly lower risk of 30% decline in eGFR compared to those without hypophosphatemia at 1- and 3-month post-transplant, but not at 12-month post-transplant. After adjusting for confounding factors, hypophosphatemia at 1- and 3-month post-transplant was an independent predictor of good kidney survival (HR 0.31, 95% CI 0.10-0.82 and HR 0.31, 95% CI 0.07-0.92, respectively).

CONCLUSIONS

Our findings suggest that hypophosphatemia during the first 3 months after kidney transplantation was associated with better kidney survival.

Higher medical costs for CKD patients with a rapid decline in eGFR: A cohort study from the Japanese general population

To investigate how changes in eGFR can affect medical costs, a regional cohort of national health insurance beneficiaries in Japan was developed from a nationwide database system (Kokuho database, KDB), and non-individualized data were obtained. From 105,661 people, subjects on chronic dialysis and subjects without consecutive medical checkups were excluded. Finally, medical costs in the follow-up year categorized by annual changes in eGFR between baseline and the next year were longitudinally examined in 70,627 people ranging in age from 40 to 74 years. Global mean costs for subjects with a rapid decrease in eGFR (≤-30%/year) were the highest among all ΔeGFR categories. In men, the cost was 1.42 times that for a stable eGFR. A total of 6,268 (19.4%) men and 5,381 (14.0%) women with eGFR <60 ml/min/1.73 m² were identified in the baseline year. The mean cost was higher with a low eGFR than without a low eGFR, and there were also higher proportions newly initiating dialysis in 2014 (low eGFR with rapid decrease in eGFR vs. with stable eGFR: 9.61% vs. 0.02% in women, P<0.001). Moreover, the costs for low eGFR subjects with a rapid decrease in eGFR were more than twice those of non-low eGFR subjects with a rapid decrease in eGFR and also compared to low eGFR subjects with a stable eGFR. Moreover, initiating chronic dialysis was considered one of the major causes of high medical costs in women with rapid eGFR decline. To the best of our knowledge, this is the first study of renal disease using a cohort developed from the KDB system recently established in Japan.

Low HDL cholesterol as a predictor of chronic kidney disease progression: a cross-classification approach and matched cohort analysis

Emerging epidemiological evidence indicates that low serum high-density lipoprotein cholesterol (HDL-C) levels are associated with the risk of progression of chronic kidney disease (CKD). However, the differences in the influence of serum HDL-C levels on CKD progression in different subcohorts have rarely been examined in detail in previous studies. The aim of this study was to investigate the significance of low serum HDL-C levels as a predictor of disease progression in CKD patients according to sub-analyses using a cross-classified subcohort. We reviewed data obtained from 120 CKD patients. Prognostic factors for renal outcome were identified by the multivariate Cox proportional hazards method. Kaplan-Meier analysis was performed to assess disease progression, which was defined as a > 30% decline in the glomerular filtration rate (GFR), or end-stage renal disease. The mean age of the included participants was 58.3 ± 13.6 years. The subjects were divided into two groups (low HDL-C vs. high HDL-C). The median follow-up period was 112.8 months. The kidney survival rate in the low HDL-C group was significantly lower than that in the high HDL-C group (P < 0.0001). However, the age-stratified analysis showed no difference between the two groups in the cohort of patients ≥ 70 years old. Multivariate Cox regression analyses showed a significant association between low HDL-C [hazard ratio (HR) 4.80, P = 0.009] and a ≥ 30% eGFR decline or ESRD. This association was more evident in the cohort of patients < 70 years old (HR 4.96, P = 0.0165), especially the female subcohort (HR 13.86, P = 0.0033). Multivariate analysis showed a significant correlation between visceral fat area and serum HDL-C levels among both male (P = 0.0017) and female (P = 0.0449) patients. In a propensity score-matched cohort (patients < 70 years old), the kidney survival rate of CKD patients was significantly lower in the low HDL-C group than in the high HDL-C group (P = 0.0364). A low serum HDL-C level is a significant predictor of CKD progression, especially in female patients with CKD under 70 years of age. This finding is of importance to clinicians when determining the expected prognosis of CKD in patients.

Hyperuricemia Predicts an Early Decline in Renal Function among Older People: A Community-Based Cohort Study

Whether elevated serum uric acid levels (SUA) predict renal dysfunction remains controversial in the elderly. Therefore, we investigated the association between SUA and early renal function decline defined as an estimated glomerular filtration rate (eGFR) reduction ≥30% over 2 years. From 2001 to 2010, we conducted a longitudinal cohort study comprising 44,078 participants aged ≥65 years in the Taipei City Elderly Health Examination Database. Participants were classified by 1-mg/dL increment of SUA. We used multivariable logistic and Cox regression analyses to compare the risk of early renal function decline in different SUA groups. Compared to the reference SUA group of 5.0–5.9 mg/dL, hyperuricemic participants had increased risks of eGFR decline, starting at SUA ≥6.0 mg/dL (adjusted odds ratio [aOR] = 1.21, 95% confidence interval [CI] = 1.00–1.45). The risk progressively elevated as SUA increased, with the highest in the SUA ≥10.0 mg/dL group (aOR = 3.20, CI = 2.39–4.28). Multivariable Cox regression further confirmed that hyperuricemia was 1.12-fold (CI = 1.03–1.22, SUA ≥6.0 mg/dL) to 1.6-fold (CI = 1.37–1.86, SUA ≥10.0 mg/dL) more likely to develop early eGFR decline. Hyperuricemia-associated increased risks for early eGFR decline were consistent across subgroup and sensitivity analyses. Collectively, SUA ≥6.0 mg/dL independently predicted early renal dysfunction with eGFR decline ≥30% over 2 years in older people.

Urinary protein and renal prognosis in idiopathic membranous nephropathy: a multicenter retrospective cohort study in Japan

Background: Several studies have revealed a relationship between proteinuria and renal prognosis in idiopathic membranous nephropathy (IMN). The benefit of achieving subnephrotic proteinuria (<3.5 g/day), however, has not been well described.

Methods: This multicenter, retrospective cohort study included 171 patients with IMN from 10 nephrology centers in Japan. The relationship between urinary protein over time and a decrease of 30% in estimated glomerular filtration rate (eGFR) was assessed using time-dependent multivariate Cox regression models adjusted for clinically relevant factors.

Results: During the observation period (median, 37 months; interquartile range, 16–71 months), 37 (21.6%) patients developed a 30% decline in eGFR, and 2 (1.2%) progressed to end-stage renal disease. Time-dependent multivariate Cox regression models revealed that lower proteinuria over time were significantly associated with a lower risk for a decrease of 30% in eGFR (primary outcome), adjusted for clinically relevant factors. Complete remission (adjusted hazard ratio [HR], 0.005 [95%CI, 0.0–0.09], p < .001), incomplete remission with <1.0 g/day of urine protein (ICR I) (adjusted HR, 0.01 [95%CI, 0.001–0.20], p = .002), and 1.0 to 3.5 g/day (ICR II) (adjusted HR, 0.12 [95%CI, 0.02–0.64], p = .013) were significantly associated with avoiding a 30% decrease in eGFR, compared to that at no remission.

Conclusions: Attaining lower proteinuria predicts good renal survival in Japanese patients with IMN. This study quantifies the impact of proteinuria reduction in IMN and the clinical relevance of achieving subnephrotic proteinuria in IMN as a valuable prognostic indicator for both the clinician and patient.

Predictive Value of Cortical Thickness Measured by Ultrasonography for Renal Impairment: A Longitudinal Study in Chronic Kidney Disease

Background: Kidney size is associated with renal function, however it is not elucidated whether kidney size is a risk for the progression of chronic kidney disease. The aim of this study was to investigate the predictive value of morphological evaluation of kidney size by ultrasonography for the progression of renal dysfunction. Methods: Morphological parameters including kidney length, volume, cortical thickness, and medullary thickness were measured by ultrasonography in 87 patients with chronic kidney disease, and adjusted by body size. Renal functions at baseline and after 2 years were measured and the associations of morphological parameters to decline in renal function over 2 years were analyzed. Results: Height-adjusted cortical thickness was correlated to decline in renal function (r = 0.426, p < 0.001). Height-adjusted cortical thickness could predict renal dysfunction with the area under the curve of 0.786, and height-adjusted cortical thickness of 4.0 mm/cm was a cut off value with a sensitivity of 72.5% and a specificity of 80.0% for the risk of a more than 30% decline in renal function or initiation of dialysis. Conclusions: We provide new insights into the utility of measuring cortical thickness by ultrasonography for predict future renal impairment.

Age Modifies the Association of Dietary Protein Intake with All-Cause Mortality in Patients with Chronic Kidney Disease

Whether the effect of a low-protein diet on progression to end-stage renal disease (ESRD) and mortality risk differs between young and elderly adults with chronic kidney disease (CKD) is unclear. We conducted a retrospective CKD cohort study to investigate the association between protein intake and mortality or renal outcomes and whether age affects this association. The cohort comprised 352 patients with stage G3-5 CKD who had been followed up for a median 4.2 years, had undergone educational hospitalization, and for whom baseline protein intake was estimated from 24-h urine samples. We classified the patients into a very low protein intake (VLPI) group (<0.6 g/kg ideal body weight/day), a low protein intake (LPI) group (0.6⁻0.8 g), and a moderate protein intake (MPI) group (>0.8 g). Compared with the LPI group, the MPI group had a significantly lower risk of all-cause mortality (hazard ratio: 0.29; 95% confidence interval: 0.07 to 0.94) but a similar risk of ESRD, although relatively high protein intake was related to a faster decline in the estimated glomerular filtration rate. When examined per age group, these results were observed only among the elderly patients, suggesting that the association between baseline dietary protein intake and all-cause mortality in patients with CKD is age-dependent.

Impaired mental health status in patients with chronic kidney disease is associated with estimated glomerular filtration rate decline

AIM

Deteriorated health-related quality of life (HRQOL) is associated with increased risk for death in both chronic kidney disease (CKD) and end-stage renal disease (ESRD) patients; however, the impact of HRQOL on CKD progression is not well investigated.

METHODS

We aimed to evaluate the association between HRQOL and CKD progression in Japanese patients with CKD. One hundred and three outpatients who visited the department of nephrology at our hospital (mean estimated glomerular filtration rate (eGFR); 32.1 ± 11.2 mL/min per 1.73 m² ) between April 2007 and March 2012 were enrolled in this study. The primary outcome was 30% decline of eGFR or ESRD. We assessed HRQOL of all participants at baseline, including the physical component summary (PCS), the mental component summary (MCS) and the role/social component summary (RCS), using SF-36. Based on the baseline score of PCS, MCS and RCS, we divided all subjects into two groups by median.

RESULTS

We studied 66 men (64.1%) and 37 women aged 61.7 ± 10.0 years old. During approximately 2.5 years of follow-up period, 59 patients (57.3%) reached 30% eGFR decline or ESRD. Cox regression analyses demonstrated that lower MCS score was significantly associated with CKD progression (hazard ratio (HR) = 1.83, 95% CI = 1.04-3.21, P = 0.035), but that lower PCS score and RCS score were not (HR = 0.70, 95% CI = 0.39-1.25, P = 0.223; HR = 0.95, 95% CI = 0.54-1.67, P = 0.854, respectively).

CONCLUSION

We found that impaired mental health was associated with CKD progression. The evaluation of the mental health should be performed in the patients with CKD.

Nrf2 activator for the treatment of kidney diseases

Kidney diseases are highly prevalent worldwide, and significantly reduce the quality of life of patients, creating an urgent need for effective therapeutic modalities. Despite this significant unmet medical need, none of the drugs launched to date have demonstrated promising potential to cure kidney diseases. This is likely due to the structural complexity of the kidney as well as difficulties in setting appropriate endpoints for clinical trials and identifying appropriate therapeutic targets. Recently, an alternative endpoint for clinical trials (i.e., a 30% or 40% reduction in estimated glomerular filtration rate [eGFR] from baseline following 2-3 years of observation) has been considered in the United States, European Union, and Japan, and is expected to contribute to the progress of drug development for kidney diseases. Further, oxidative stress and inflammation are currently thought to be key factors in the progression of kidney diseases, prompting more research on drugs targeting the mechanisms related to these factors for treatment. The Kelch-like ECH-associated protein 1-nuclear factor erythroid 2-related factor 2 (Keap1-Nrf2) system has drawn much attention in recent years for its anti-oxidative and anti-inflammatory properties, and its pharmacological potential for treatment of kidney diseases is being widely investigated in both clinical and non-clinical studies. This review summarizes the current issues in the treatment of kidney diseases, including clinical endpoints, Nrf2 activators as treatment options, and perspectives on pharmaceutical applications of Nrf2 activators.

Nephrotoxicity and highly active antiretroviral therapy: Mitigating action of Momordica charantia

Momordica charantia (M. charantia) is known for its antioxidant and antidiabetic properties. The aim of this study is to investigate the renoprotective effects of M. charantia in rats following treatment with highly active antiretroviral therapy (HAART) regimen triplavar. Adult male Sprague-Dawley rats weighing 178.1-220.5 g (n = 36) were divided into six groups (A-F) with each group comprising of six (n = 6) rats. The drugs and extract were administered via oral gavage. The therapeutic dose of triplavar was adjusted using the human therapeutic dose equivalent for the rat model. Animals were euthanized on the tenth week with kidneys removed for examination and blood obtained via cardiac puncture. Levels of oxidative stress enzymes (superoxide dismutase-SOD, catalase-CAT, and reduced glutathione-GSH) were significantly lowered in all groups not receiving M. charantia. The levels of thiobarbituric acid reactive substances (TBARS) were increased resulting in free radical formation via auto-oxidation. Renal parameters showed no albuminuria, normal blood urea nitrogen (BUN), serum creatinine (SCr) and electrolytes in groups treated with M. charantia. HAART treated (Group B) showed severe albuminuria, a significantly (p < 0.05) raised BUN and SCr and gross electrolyte disturbances. Blood glucose levels were significantly raised in groups not receiving the adjuvant M. charantia (p < 0.05). Histopathology in HAART treated animals showed glomerular capillary abnormalities and cellular infiltrations while M. charantia treated animals showed an essentially normal glomerular appearance with capillary loops and normal cytoarchitecture. In conclusion M. charantia extract administration improved blood glucose levels, restored renal histology, reinstate renal function, reduce body weight loss and restores hyperglycemia.

Estimated glomerular filtration rate decline and risk of end-stage renal disease in type 2 diabetes

Background

According to studies by the National Kidney Foundation and Food and Drug Administration, 30% and 40% declines in estimated glomerular filtration rate (eGFR) could be used as surrogate endpoints of end-stage renal disease (ESRD). However, the benefits of using these endpoints in diabetic patients remain unclear.

Methods

This cohort study comprised Japanese patients with type 2 diabetes; those with repeated serum creatinine measurements during a baseline period of 2 years (n = 1868) or 3 years (n = 2001) were enrolled. Subsequent risks of ESRD following eGFR declines were assessed.

Results

In the 2-year baseline analysis, the cumulative prevalence of −20%, −30%, −40%, and −53% changes in eGFR were 23.9%, 11.1%, 6.8%, and 3.7%, respectively. There were 133 cases (7.1%) of subsequent ESRD during a median follow-up period of 6.5 years. In the 3-year baseline analysis, the corresponding proportions were 28.1%, 14.0%, 7.7%, and 3.9%, respectively, with 110 participants (5.5%) reaching ESRD during a median follow-up period of 5.5 years. The adjusted hazard ratios of subsequent ESRD following −53%, −40%, −30%, and −20% changes in eGFR during the 2-year baseline period were 22.9 (11.1–47.3), 12.8 (6.9–23.7), 8.2 (4.3–15.5), and 3.9 (2.2–7.0), respectively when compared with the no changes in eGFR. In the 3-year baseline analysis, the corresponding risks were 29.7 (10.8–81.9), 18.4 (7.6–44.7), 12.8 (5.2–32.2), and 5.4 (2.3–12.8), respectively. In the subgroup analysis, similar trends were observed in patients with macroalbuminuria at baseline.

Conclusions

Declines in eGFR were strongly associated with subsequent risk of ESRD in Japanese type 2 diabetic patients. In addition to 30% and 40% declines, a 20% decline in eGFR over 2 years could be considered as a candidate surrogate endpoint of ESRD in diabetic kidney disease.

Urinary type IV collagen excretion is involved in the decline in estimated glomerular filtration rate in the Japanese general population without diabetes: A 5-year observational study

Urinary type IV collagen (U-Col4) and albumin excretion is evaluated to monitor the development of diabetic kidney disease. However, U-Col4 excretion in the general population without diabetes has not yet been fully elucidated. In this study, 1067 participants without diabetes and with urinary albumin-creatinine ratio <300 mg/gCr (normo- or microalbuminuria) who underwent an annual health examination in 2004 were enrolled and observed for 5 years. They were divided according to the amount of U-Col4 or urinary albumin excreted. The decline in estimated glomerular filtration rate (eGFR) was calculated. In participants with eGFR ≥80 mL/min, abnormal U-Col4 excretion was indicated as a significant independent risk factor for 10% eGFR change per year, which is one of the prognostic factors for the development of end-stage kidney disease. Moreover, in contrast to urinary albumin excretion, U-Col4 excretion was not related to age or kidney function, suggesting that some individuals with abnormal U-Col4 excretion can have an independent hidden risk for the development of kidney dysfunction. In conclusion, it is important to measure U-Col4 excretion in the general population without diabetes to determine changes in renal features in every individual and help detect future complications such as diabetic kidney disease. If U-Col4 excretion is abnormal, kidney manifestation should be carefully followed up, even if the kidney function and urinalysis findings are normal.

Importance of glomerular filtration rate change as surrogate endpoint for the future incidence of end-stage renal disease in general Japanese population: community-based cohort study

Background

Because of the necessity for extended period and large costs until the event occurs, surrogate endpoints are indispensable for implementation of clinical studies to improve chronic kidney disease (CKD) patients’ prognosis.

Methods

Subjects with serum creatinine level for a baseline period over 1–3 years were enrolled (n = 69,238) in this community-based prospective cohort study in Okinawa, Japan, and followed up for 15 years. The endpoint was end-stage renal disease (ESRD). The percent of estimated glomerular filtration rate (%eGFR) change was calculated on the basis of the baseline period.

Results

Subjects had a mean ± SD age, 55.59 ± 14.69 years; eGFR, 80.15 ± 21.15 ml/min/1.73 m². Among the subjects recruited, 15.81% had a low eGFR (<60 ml/min/1.73 m²) and 36.1/100,000 person years developed ESRD. Cox proportional hazards models adjusted for baseline characteristics showed that the risk of ESRD tended to be high with high rates of decrease in %eGFR changes over 2 or 3 years in the high- and low-eGFR groups. The specificities and positive predictive values for ESRD based on a cutoff value of %eGFR change of less than −30% over 2 or 3 years were high in the high- and low-eGFR groups.

Conclusions

%eGFR change tends to be associated with the risk of ESRD. %eGFR change of less than −30% over 2 or 3 years can be a candidate surrogate endpoint for ESRD in the general Japanese population.