Glomerular Filtration Rate Slope Research Articles

P1639DEVELOPMENT OF SELF-LIMITED LOW-LEVEL BK VIREMIA/VIRURIA SUGGESTS IDEAL IMMUNOSUPPRESSION TO SUPPRESS T-CELL AND ANTIBODY-MEDIATED REJECTION AND PRESERVE KIDNEY ALLOGRAFT FUNCTION

Abstract Background and Aims Polyomavirus BK (BKV) viremia has been suggested as a surrogate marker of overimmunosuppression. Due to recent advances in monitoring strategies and pre-emptive therapy, progression to BKV-associated nephropathy (BKVN) has been reduced. Reduction of maintenance immunosuppression during BKVN, however, has been associated with both T-cell mediated rejection (TCMR), antibody-mediated rejection (ABMR), and inferior kidney allograft outcomes. Although the administration of intravenous immunoglobulins (IVIG) failed to treat BKVN, IVIG may have properties to reduce allosensitization. Method We studied 860 kidney transplant recipients (KTRs) predominantly under tacrolimus-based triple-drug maintenance immunosuppression from 2009 to 2018. We identified 130 KTRs (15.1%) with high-level BK viremia >10,000 copies/mL (presumptive BKVN), 180 KTRs (20.9%) with low-level BK viremia <10,000 copies/mL, 85 KTRs (9.9%) with isolated BK viruria, and 465 KTRs (54.1%) with no BK viruria/viremia. Kidney allograft outcomes with respect to TCMR, ABMR, development of de novo donor-specific antibodies (DSA), kidney allograft survival, and estimated glomerular filtration rate (eGFR) slope were analysed. Due to the increased incidence of TCMR and ABMR among KTRs with presumptive BKVN, 48 of 130 KTRs (36.9%) with high-level BK viremia starting from 2015 received IVIG (0.5 g/kg of body weight) on a biweekly basis during BKV replication. Results Very interestingly, KTRs with low-level BK viremia/viruria showed a significantly lower incidence of TCMR compared to KTRs with no BK viremia/viruria and KTRs with high-level BK viremia (p<0.05). In addition, KTRs with low-level BK viremia/viruria showed a significantly lower incidence of ABMR compared to KTRs with high-level BK viremia (p<0.05). No differences were observed with respect to the development of de novo DSA (MFI>5000) between KTRs with low-level BK viremia/viruria, KTRs with no BK viremia/viruria, and KTRs with high-level BK viremia (p>0.05). KTRs with low-level BK viremia/viruria showed superior kidney allograft survival and lower eGFR slope compared to KTRs with no BK viremia/viruria and KTRs with high-level BK viremia (p<0.05). The administration of IVIG during high-level BK viremia didn’t impact the development of TCMR, ABMR, development of de novo DSA, eGFR slope, and kidney allograft survival (p<0.05). Conclusion Our results show that low-level BK viremia/viruria is associated with suppression of TCMR and ABMR in the early period posttransplantation, and preservation of kidney allograft function in the long-term. The administration of IVIG didn’t prove beneficial to reduce allosensitization among KTRs with high-level BK viremia.

P0795OUTCOME COMPARISON STUDY ACCORDING TO THE CAUSE OF CHRONIC KIDNEY DISEASE: RESULTS FROM KNOW-CKD STUDY

Abstract Background and Aims The cause of chronic kidney disease (CKD) is one of important factors for predicting the outcome. However, relative risks for the adverse outcomes according to the specific causes of CKD is unknown. Method Using the longitudinal data of prospective cohort of Korean predialysis CKD, KNOW-CKD cohort, the relative risk of end-stage renal disease (ESRD), composite of ESRD development or creatinine doubling, and composite of cardiovascular disease (CVD) and all-cause mortality according to the cause of CKD were compared. The patients were subgrouped in to four categories at the study entry according to the cause of CKD: glomerulonephritis (GN), diabetic nephropathy (DN), hypertensive nephropathy (HTN), and polycystic kidney disease (PKD). Since the baseline characteristics differed according to the causes of CKD, the inverse probability of treatment weighting (IPTW) methods was used to exclude the effects of other variables on the outcomes. The estimated glomerular filtration rate (eGFR) slope during follow-up was calculated for each cause of CKD using linear mixed model Results During the median follow-up of 4.1 years (interquartile range 1.12-7.12 years) total 441 (21.5%) of ESRD, 556 (27.1%) of composite of ESRD or creatinine doubling and 190 (9.3%) composite of CVD and all cause death occurred. In the IPTW adjusted cohorts, DN and PKD showed significantly increased hazard ratios of 1.85 and 5.57 for ESRD development and 1.74 and 4.57 for composite of ESRD developement or creatinine doubling, respectively, compared to GN in the fully adjusted model. Regarding compsite of CVD and all-cause death, also DN and PKD showed significantly increased hazard ratios of 1.93 and 2.16 compared to GN. The adjusted eGFR slope for DN, HTN and PKD was -2.32, -0.90, and -2.41 mL/min/1.73m2 per year, respectively, and all differ statistically significantly compared to GN (eGFR slope of -1.49 mL/min/1.73m2 per year). During the follow-up, GN and DN showed linear declining pattern however, HTN and PKD showed convex linear pattern. Conclusion The DN and PKD showed relatively higher risks for renal progression and composite of CVD and death compared to GN.

TO002REDUCTION IN THE RATE OF EGFR DECLINE WITH SEMAGLUTIDE VS PLACEBO: A POST HOC POOLED ANALYSIS OF SUSTAIN 6 AND PIONEER 6

Abstract Background and Aims The SUSTAIN 6 cardiovascular outcomes trial (CVOT) indicated that once-weekly (OW) subcutaneous (s.c.) semaglutide may have beneficial effects on kidney function. SUSTAIN 6 and the more recent PIONEER 6 CVOT (oral semaglutide) had similar designs and subject populations; both evaluated the effects of semaglutide compared with placebo on important macro- and microvascular outcomes. This post hoc analysis of pooled data from the two trials evaluated the effects of semaglutide vs placebo on kidney function, assessed by estimated glomerular filtration rate (eGFR) slope. Method Data for 6,480 subjects from SUSTAIN 6 (OW s.c. semaglutide 0.5 and 1.0 mg or placebo, n=3,297; median follow-up 2.1 years) and PIONEER 6 (oral semaglutide once-daily 14 mg or placebo, n=3,183; median follow-up 1.3 years) were pooled into two groups: semaglutide and placebo. Annual change in eGFR was compared between semaglutide and placebo in patients with eGFR data at baseline, both overall and by baseline eGFR subgroup (≥30–<60 or ≥60 mL/min/1.73 m2). Data were analysed using a linear random regression model with individual intercept and time slope. Estimated treatment difference (ETD) between annual rates of eGFR slope (from baseline to timepoint of interest) was calculated at Year 1 and Year 2 (Year 2 data predominantly from SUSTAIN 6); interaction p-values indicated differences between subgroups. Results In the overall treatment population, the annual rate of eGFR change was 0.60 mL/min/1.73 m2 (95% confidence interval [CI]: 0.31;0.90; p<0.0001) lower with semaglutide vs placebo in Year 1. In the subgroup with an eGFR ≥60 mL/min/1.73 m2 at baseline, the ETD for semaglutide vs placebo at Year 1 was 0.48 mL/min/1.73 m2/year (95% CI: 0.13;0.82). Whereas, at Year 1, the subgroup with eGFR ≥30–<60 mL/min/1.73 m2 had an ETD of 1.07 mL/min/1.73 m2/year (95% CI: 0.46;1.68) (Table). Accordingly, a numerically larger difference in ETD was observed in the eGFR ≥30–<60 mL/min/1.73 m2 vs the eGFR ≥60 mL/min/1.73 m2 subgroup (not statistically significant; pinteraction=0.21). Conclusion Semaglutide was associated with a significantly smaller decline in renal function compared with placebo in subjects across stages of impaired kidney function at baseline. Although benefits were observed in the overall population, the findings indicate that the primary benefit may be observed in those with established chronic kidney disease. Table Annual eGFR change with semaglutide or placebo and ETD between semaglutide and placebo in pooled SUSTAIN 6 and PIONEER 6 trials

SAT-153 CORRELATION BETWEEN HBA1c LEVEL AND RENAL FUNCTION IN DIABETIC NEPHROPATHY

Tight glycemic control may have limited effect on the protection of renal function. No large clinical trials conducted since 2000 have clearly shown that the management goal of HbA1C is 6% better than 7%. In addition, recent clinical trials of many new drugs have compared the HbA1c levels of 8% and 7% groups. Therefore, in this study, HbA1C was divided into each stratum by 1%, and the effect of HbA1c level on renal function was examined. This single-center retrospective observational study examined the HbA1C and Cr data of patients for five consecutive years between 2007 and 2017, beginning from the date of the first measurement of HbA1C. Annual mean values were used as representative values for blood tests. Considering the possibility of a high HbA1C level in the first year, the mean HbA1C level after year 2 was calculated, and the four groups (6%, 7%, 8% and 9%) were compared. Primary endpoints were mean estimated glomerular filtration rate (eGFR) slope and the proportion of patients with rapid renal insufficiency (≥ 5 mL/min/1.73 m2/year). Dialysis patients and those aged 18 years or younger were excluded from the study. The HbA1C 6%, 7%, 8% and 9% groups consisted of 630, 399, 95, and 23 subjects, respectively. The mean ages of these groups were 64.6, 65.0, 60.6, and 61.0 years, respectively, and the mean HbA1C during the course was 6.5 ± 0.3, 7.4 ± 0.3, 8.4 ± 0.3, and 9.4 ± 0.3, respectively. The mean eGFR at 1 year was 69.6, 70.7, 75.7, and 78.4 ml/min/1.73 m2, respectively. The higher the HbA1C level, the greater was the eGFR slope. The eGFR slopes were -1.2 ± 2.8, 1.2 ± 2.7, 1.5 ± 3.3, and 2.6 ± 3.6 mL/min/1.73 m2/year for the four groups, respectively. The incidence of rapid decreased renal function was 7.3%, 6.5%, 10.5% and 21.7% for HbA1C 6%, 7%, 8% and 9% groups, respectively, showing similar tendency with the eGFR slope. Furthermore, only the 6% and 7% groups were analyzed by matching background factors, but no significant difference was found (P = 0.74). In the present study, there was no significant difference in either the eGFR slope or the percentage of patients with rapid decreased renal function between HbA1C in the 6% and 7% ranges.

Determinants of the intercept and slope of glomerular filtration rate in recipients of alive donor kidney transplant.

SummaryBackgroundDonor kidney function is considered a critical determinant of allograft survival after live donor (LD) kidney transplantation, but its independent impact on the evolution of graft function is less well defined. The objective of this study was to dissect the relative contribution of LD kidney function to baseline estimated glomerular filtration rate (eGFR) of recipients and its decline.MethodsIn this study 91 LD kidney transplantations performed between 2007 and 2015 were included. The eGFR of donated kidneys (eGFR-dk) was calculated from total LD eGFR (eGFR-dt) based on the results of isotope nephrography. Recipient eGFR (eGFR-r) determined 6‑monthly until 36 months posttransplantation served as dependent variable in mixed linear models estimating changes in baseline allograft function (intercept) and eGFR‑r slope. Models were adjusted either for eGFR-dk or eGFR-dt, in addition to other potential confounders.ResultsOverall, unadjusted mean eGFR‑r at baseline (6 months) and its annual decline in allograft function were 56.5 mL/min/1.73 m2 and −0.2 mL/min/1.73 m2, respectively. In multivariate analysis, eGFR-dk impacted on baseline eGFR‑r (0.6 mL/min/1.73 m2 mean estimated increase per unit; P = 0.02) but not on its slope. In the eGFR-dt-adjusted model, a marginal effect was observed for LD age (P = 0.05). Both models identified antibody-mediated rejection (ABMR) as the strongest risk factor of accelerated loss of allograft function (eGFR‑r slope: approximately −6 mL/min/1.73 m2 per year; P ≤ 0.02).ConclusionDonor-related characteristics, most prominently the function of donated kidneys and LD age, were predictive of eGFR at baseline. The ABMR was identified as the cardinal cause of progressive deterioration of allograft function.

Rethinking clinical endpoints in kidney transplant trials.

Clinical trials testing novel kidney transplant therapies are challenged by low rates of long-term clinical outcomes such as death and graft loss. Herein, we critically review traditional and more recent strategies to expedite new therapies by minimizing sample size and follow-up duration using surrogates (alone or in the context of composite endpoints), or using different clinical endpoints. Multiple surrogate endpoints are increasingly important for organ transplantation trial design: glomerular filtration rate slope, albuminuria, donor-specific alloantibodies, and histological score at graft protocol biopsies. However, surrogate endpoint use is limited by bias when data are missing. Hierarchical multiple primary endpoints - that are successfully used in other settings and frequently utilize surrogate endpoints - have not yet been integrated into kidney transplant studies. New clinical endpoints, focusing on treatment safety and patient quality of life have been recently standardized and should be reported regardless of the primary endpoint of any randomized controlled trial. Defining surrogates, standards for outcome reporting, and statistical strategies to appropriately analyze them are critical to effectively testing and implementing novel therapeutic strategies to improve long-term clinical outcomes in kidney transplantation.

Chronic kidney disease progression and mortality risk profiles in Germany: results from the Chronic Kidney Disease Outcomes and Practice Patterns Study.

BackgroundChronic kidney disease (CKD) progression among German patients in a representative setting has not been described previously. The Verband Deutsche Nierenzentren and Chronic Kidney Disease Outcomes and Practice Patterns Study established a longitudinal observational cohort among German CKD patients to research variations in patient care and outcomes in real-world nephrology practices.MethodsA cohort of CKD Stages 3 (25%) and 4 (75%) patients was established from German nephrologist-run CKD clinics in 2013–16. Linear models were used to determine the estimated glomerular filtration rate (eGFR) slope during follow-up and Cox models were used to assess outcomes of end-stage kidney disease (ESKD) and death.ResultsA total of 1834 patients (median age 75 years, 58% male, 42% diabetics, median baseline eGFR 25 mL/min/1.73 m2) were followed for a median of 29 months. More than 50% had slow or no decline and 17% declined ≥5 mL/min/1.73 m2/year. After 4.5 years, the incidence of ESKD was 8% and of deaths without ESKD 16% among patients with eGFR ≥30 mL/min/1.73 m2 and 37% and 19% for eGFR <30 mL/min/1.73 m2. Adjusted models showed higher risks of ESKD or death for patients with worse kidney function at baseline, male sex, diabetes and higher blood pressure; a higher risk of ESKD with higher albuminuria; and a higher risk of death with older age or cardiovascular comorbidity.ConclusionsRoutine nephrology care of patients in Germany comprises mostly elderly patients, many with slow CKD progression. Identification of risk factors for CKD progression and mortality may help guide resources by closer follow-up of high-risk patients.

Urinary Angiotensinogen in addition to Imaging Classification in the Prediction of Renal Outcome in Autosomal Dominant Polycystic Kidney Disease.

BackgroundIntrarenal renin-angiotensin system (RAS) is known to play the major role in the development of hypertension and renal progression in autosomal dominant polycystic kidney disease (ADPKD). Urinary angiotensinogen to creatinine ratio (AGT/Cr) was suggested as a novel biomarker to reflect intrarenal RAS activity. This study was performed to evaluate urinary AGT/Cr as a predictive biomarker for renal function decline in addition to imaging classification in a prospective ADPKD cohort.MethodsFrom 2011 to 2016, a total of 364 ADPKD patients were enrolled in the prospective cohort called the KoreaN Cohort Study for Outcomes in Patients With Chronic Kidney Disease (KNOW-CKD). Among them, a total of 207 subjects in chronic kidney disease stage 1–4 with baseline urinary AGT and total kidney volume and subsequent renal function follow-up data over more than 1 year were included in the analysis. Patients were defined as slow progressors (SP) if they are classified as 1A or 1B by imaging classification whereas rapid progressors (RP) if they are classified as 1C–1E. Patients were divided according to AGT/Cr quartiles and annual estimated glomerular filtration rate (eGFR) slope was compared among highest quartile (hAGT group) and the rest of quartiles (lAGT group). Patients were divided into 4 groups to evaluate the predictive value of urinary AGT/Cr in addition to imaging classification: SP/lAGT, SP/hAGT, RP/lAGT, and RP/hAGT. The Cox regression model was used to evaluate the hazard ratio (HR) between groups.ResultsThe mean age was 45.9 years and 88.9% had hypertension. Baseline eGFR was 79.0 ± 28.4 mL/min/1.73 m2 and median height-adjusted total kidney volume was 788.2 (471.2; 1,205.2) mL/m. The patients in the hAGT group showed lower eGFR (72.4 ± 24.8 vs. 81.1 ± 29.2 mL/min/1.73 m2, P = 0.039), lower plasma hemoglobin (13.0 ± 1.4 vs. 13.7 ± 1.6 g/dL, P = 0.007), higher urinary protein to creatinine ratio (0.14 [0.09, 0.38] vs. 0.07 [0.04, 0.12] g/g, P = 0.007) compared to the lAGT group. The hAGT group was an independent risk factor for faster eGFR decline after adjusting for gender, RP, baseline eGFR, and other known risk factors. During median follow-up duration of 4.6 years, a total of 29 renal events (14.0%) occurred. The SP/hAGT group showed significantly higher risk of developing renal outcome compared to SP/lAGT group (HR, 13.4; 95% confidence interval, 1.282–139.324; P = 0.03).ConclusionUrinary AGT/Cr can be a useful predictive marker in the patients with relatively small ADPKD. Various biomarkers should be considered to define RP when implementing novel treatment in the patients with ADPKD.

Increased Proteinuria is Associated with Increased Aortic Arch Calcification, Cardio-Thoracic Ratio, Rapid Renal Progression and Increased Overall and Cardiovascular Mortality in Chronic Kidney Disease.

Background: Patients with chronic kidney disease (CKD) are associated with high prevalence rates of proteinuria, vascular calcification and cardiomegaly. In this study, we investigated relationships among proteinuria, aortic arch calcification (AoAC) and cardio-thoracic ratio (CTR) in patients with CKD stage 3A-5. In addition, we investigated correlations among proteinuria and decline in renal function, overall and cardiovascular (CV) mortality.Methods: We enrolled 482 pre-dialysis patients with CKD stage 3A-5, and determined AoAC and CTR using chest radiography at enrollment. The patients were stratified into four groups according to quartiles of urine protein-to-creatinine ratio (UPCR).Results: The patients in quartile 4 had a lower estimated glomerular filtration rate (eGFR) slope, and higher prevalence rates of rapid renal progression, progression to commencement of dialysis, overall and CV mortality. Multivariable analysis showed that a high UPCR was associated with high AoAC (unstandardized coefficient β: 0.315; p = 0.002), high CTR (unstandardized coefficient β: 1.186; p = 0.028) and larger negative eGFR slope (unstandardized coefficient β: -2.398; p < 0.001). With regards to clinical outcomes, a high UPCR was significantly correlated with progression to dialysis (log per 1 mg/g; hazard ratio [HR], 2.538; p = 0.003), increased overall mortality (log per 1 mg/g; HR, 2.292; p = 0.003) and increased CV mortality (log per 1 mg/g; HR, 3.195; p = 0.006).Conclusions: Assessing proteinuria may allow for the early identification of high-risk patients and initiate interventions to prevent vascular calcification, cardiomegaly, and poor clinical outcomes.

Low erythropoietin levels predict faster renal function decline in diabetic patients with anemia: a prospective cohort study

Elevated erythropoietin (EPO) levels have been reported to predict poor survival in various populations including diabetic patients. However, data regarding its impact on renal outcomes are scarce. We conducted a single-center, prospective cohort study of 339 type 2 diabetic patients with anemia. The primary outcome was the estimated glomerular filtration rate (eGFR) slope for two years. We performed multiple linear regression and restricted cubic spline analyses to assess the association of serum EPO levels with the renal outcome. Chronic kidney disease (CKD) was defined as eGFR <60 mL/min/1.73 m2 or urine albumin-to-creatinine ratio >30 mg/g creatinine. Median baseline EPO and eGFR level were 14.4 IU/L and 53 mL/min/1.73 m2, respectively. Inappropriately low EPO levels were observed in 73% of anemic patients and 59% of anemic patients even without CKD, suggesting that EPO deficiency precedes the onset of CKD in diabetes mellitus. Multivariable analysis revealed that iron status and hemoglobin levels were major determinants of EPO levels. Median eGFR slope was −1.3 mL/min/1.73 m2/year. We found that low EPO levels, but not low hemoglobin levels, were associated with a faster decline in eGFR, independent of clinically relevant factors. The eGFR decline was steeper, particularly when the EPO level was below the upper limit of normal. Lower EPO concentrations were associated with rapid eGFR decline, especially in patients with iron deficiency (P for interaction = 0.01). Relative EPO deficiency should be considered as a culprit in anemia of unknown etiology in diabetic patients, even those without CKD. Low EPO levels, especially when accompanied by poor iron status, are predictive of rapid loss of renal function.

Change in Albuminuria and GFR as End Points for Clinical Trials in Early Stages of CKD: A Scientific Workshop Sponsored by the National Kidney Foundation in Collaboration With the US Food and Drug Administration and European Medicines Agency

The US Food and Drug Administration (FDA) and European Medicines Agency (EMA) are currently willing to consider a 30% to 40% glomerular filtration rate (GFR) decline as a surrogate end point for kidney failure for clinical trials of kidney disease progression under appropriate conditions. However, these end points may not be practical for early stages of kidney disease. In March 2018, the National Kidney Foundation sponsored a scientific workshop in collaboration with the FDA and EMA to evaluate changes in albuminuria or GFR as candidate surrogate end points. Three parallel efforts were presented: meta-analyses of observational studies (cohorts), meta-analyses of clinical trials, and simulations of trial design. In cohorts, after accounting for measurement error, relationships between change in urinary albumin-creatinine ratio (UACR) or estimated GFR (eGFR) slope and the clinical outcome of kidney disease progression were strong and consistent. In trials, the posterior median R2 of treatment effects on the candidate surrogates with the clinical outcome was 0.47 (95% Bayesian credible interval [BCI], 0.02-0.96) for early change in UACR and 0.72 (95% BCI, 0.05-0.99) when restricted to baseline UACR>30mg/g, and 0.97 (95% BCI, 0.78-1.00) for total eGFR slope at 3 years and 0.96 (95% BCI, 0.63-1.00) for chronic eGFR slope (ie, the slope excluding the first 3 months from baseline, when there might be acute changes in eGFR). The magnitude of the relationships of changes in the candidate surrogates with risk for clinical outcome was consistent across cohorts and trials: a UACR reduction of 30% or eGFR slope reduction by 0.5 to 1.0mL/min/1.73m2 per year were associated with an HR of ∼0.7 for the clinical outcome in cohorts and trials. In simulations, using GFR slope as an end point substantially reduced the required sample size and duration of follow-up compared with the clinical end point when baseline eGFR was high, treatment effects were uniform, and there was no acute effect of the treatment. We conclude that both early change in albuminuria and GFR slope fulfill criteria for surrogacy for use as end points in clinical trials for chronic kidney disease progression under certain conditions, with stronger support for change in GFR than albuminuria. Implementation requires understanding conditions under which each surrogate is likely to perform well and restricting its use to those settings.

Factors Affecting eGFR Slope of Renal Transplant Patients During the First 2 Years

PurposeIn healthy individuals, glomerular filtration rate decreases by 1 mL/min/y after a peak level of 125.0 mL/min has been reached in adulthood. Any reduction greater than this is a progressive slope (slope more negative than −1 mL/min/y, stable [−1 to +1]), or an improvable slope if it shows more of an increase, that is, greater than +1.0 mL/min/y). The aim of the study was to determine the factors affecting estimated glomerular filtration rate (eGFR) slope during the first 2 years of renal transplant in patients with negative pretransplant panel-reactive antibody. Materials and MethodsThe characteristics of 59 renal transplant patients, such as age, sex, etiology, and 2 years of laboratory data, were collected retrospectively. For each patient, the eGFR decline rate (slope) (mL/min−1/1.73 m2−1/y−1) was determined by linear regression analysis using all calculated eGFR values over the study period. FindingsOf 59 patients, 7 (11.8%) had a progressive slope, 22 (37.2%) had a stable slope, and 30 (50.8%) had an improvable slope. The first-year mean tacrolimus level was lower in patients with progressive slope than in the patients with stable slope and improvable slope (P < .022). The determinants of eGFR slope in multiple regression analysis were post-transplant hypertension (β = −0.393; P = .002) and the first-year mean tacrolimus level (β = 0.320; P = .01), whereas age, serum albumin, and 2-year mean tacrolimus level did not reach the level of significance. ConclusionKeeping tacrolimus levels high in the first year to prevent eGFR declining is important.

Evaluating Glomerular Filtration Rate Slope as a Surrogate End Point for ESKD in Clinical Trials: An Individual Participant Meta-Analysis of Observational Data.

Decline in eGFR is a biologically plausible surrogate end point for the progression of CKD in clinical trials. However, it must first be tested to ensure strong associations with clinical outcomes in diverse populations, including patients with higher eGFR. To investigate the association between 1-, 2-, and 3-year changes in eGFR (slope) with clinical outcomes over the long term, we conducted a random effects meta-analysis of 3,758,551 participants with baseline eGFR≥60 ml/min per 1.73 m2 and 122,664 participants with eGFR<60 ml/min per 1.73 m2 from 14 cohorts followed for an average of 4.2 years. Slower eGFR decline by 0.75 ml/min per 1.73 m2 per year over 2 years was associated with lower risk of ESKD in participants with baseline eGFR≥60 ml/min per 1.73 m2 (adjusted hazard ratio, 0.70; 95% CI, 0.68 to 0.72) and eGFR<60 ml/min per 1.73 m2 (0.71; 95% CI, 0.68 to 0.74). The relationship was stronger with 3-year slope. For a rapidly progressing population with predicted 5-year risk of ESKD of 8.3%, an intervention that reduced eGFR decline by 0.75 ml/min per 1.73 m2 per year over 2 years would reduce the ESKD risk by 1.6%. For a hypothetical low-risk population with a predicted 5-year ESKD risk of 0.58%, the same intervention would reduce the risk by only 0.13%. Slower decline in eGFR was associated with lower risk of subsequent ESKD, even in participants with eGFR≥60 ml/min per 1.73 m2, but those with the highest risk would be expected to benefit the most.

Creatinine- and cystatin C-based estimated glomerular filtration rate slopes for the prediction of kidney outcome: a comparative retrospective study

BackgroundMany studies have evaluated the usefulness of creatinine- (eGFRcr) and cystatin C-based estimated glomerular filtration rate (eGFRcys) at specific time points in predicting renal outcome. This study compared the performance of both eGFR changing slopes in identifying patients at high risk of end-stage renal disease (ESRD).MethodsFrom 2012 to 2017, patients with more than three simultaneous measurements of serum creatinine and cystatin C for 1 year were identified. Rapid progression was defined as eGFR slope < − 5 mL/min/1.73 m2/year. The primary outcome was progression to ESRD.ResultsOverall, 1323 patients were included. The baseline eGFRcr and eGFRcys were 39 (27–48) and 38 (27–50) mL/min/1.73 m2, respectively. Over 2.9 years (range, 2.0–3.8 years) of follow-up, 134 subjects (10%) progressed to ESRD. Both the eGFRcr and eGFRcys slopes were associated with a higher risk of ESRD, independently of baseline eGFR (hazard ratio [HR] = 0.986 [0.982–0.991] and HR = 0.988 [0.983–0.993], respectively; all p < 0.001). The creatinine- and cystatin C-based rapid progressions were associated with increased risk of ESRD (HR = 2.22 [1.57–3.13], HR = 2.03 [1.44–2.86], respectively; all p < 0.001). In the subgroup analyses, the rapid progression group, defined on the basis of creatinine levels (n = 503), showed no association between the eGFRcys slope and ESRD risk (p = 0.31), whereas the eGFRcr slope contributed to further discriminating higher ESRD risk in the subjects with rapid progression based on eGFRcys slopes (n = 463; p = 0.003).ConclusionsBoth eGFR slopes were associated with future ESRD risk. The eGFRcr slope was comparable with the eGFRcys slope in predicting kidney outcome.

Treating Posttransplant Anemia With Erythropoietin Improves Quality of Life but Does Not Affect Progression of Chronic Kidney Disease.

Posttransplant anemia affects 30% to 45% of kidney transplant recipients and is associated with increased morbidity. However, there is lack of evidence about safe hemoglobin levels after erythropoietin treatment. Studies are needed to better understand the potential benefits and risks, as well as to define safe target hemoglobin ranges in these patients. In this single-center exploratory, open-label randomized controlled trial, kidney trans-plant recipients with anemia 3 months posttransplant were either treated with epoetin beta to a hemoglobin target level of 11.5 to 13.5 g/dL (n = 28) or given no treatment (n = 27). Treatment effects on graft function and health quality of life were assessed. After 2 years, hemoglobin concentrations were significantly higher in the epoetin beta treatment group than in the no treatment group (12.3 ± 0.18 vs 9.99 ± 0.22 g/dL; P < .0001). Estimated glomerular filtration rate, calculated by Modified Diet in Renal Disease 7, declined by 1.7 mL/min (interquartile range, -6 to 4.24) in the epoetin treatment group and by 4.16 mL/min (interquartile range, -12.42 to 2.78) in the no treatment group (P = .32). Rate of progression, determined by estimated glomerular filtration rate slope, was not significantly different between groups (-0.09 ± 0.1 vs -0.12 ± 0.15 mL/min for treated vs not treated; P = .78). Moreover, we observed no significant differences in proteinuria and blood pressure. Treated patients had greater improvements in the vitality and mental health domains of the Medical Outcomes Short Form Health Survey quality of life scores. Treatment of anemia in kidney transplant recipients to a hemoglobin level of 11.5 to 13.5 g/dL with erythropoietin improves some quality of life scores. The treatment was safe and not associated with adverse outcomes. There were no changes in rate of decline of graft function.

Blood Pressure, Chronic Kidney Disease Progression, and Kidney Allograft Failure in Kidney Transplant Recipients: A Secondary Analysis of the FAVORIT Trial.

In chronic kidney disease, intensive systolic blood pressure (SBP) control reduces mortality at a cost of greater acute kidney injury risk. Kidney transplantation involves implantation of denervated kidneys and immunosuppressive medications that increase acute kidney injury risk. The optimal blood pressure (BP) target in kidney transplant recipients (KTRs) is uncertain. Prior observational studies from the Folic Acid for Vascular Outcome Reduction in Transplantation (FAVORIT) trial demonstrate associations of lower SBP levels and reduced mortality risk, but the relationship of BP with kidney allograft function remains unknown. Thus, in FAVORIT, we investigated the relationship of SBP and diastolic blood pressure (DBP) with risk of kidney allograft failure and estimated glomerular filtration rate (eGFR) slope among stable KTRs. Cox proportional hazards and multivariable linear regression models adjusted for demographics, transplant characteristics, comorbidities, baseline eGFR, and urine albumin-to-creatinine ratio were used to determine associations of SBP and DBP with time to a composite kidney outcome of ≥50% eGFR decline or dialysis dependence, and with annualized eGFR change, respectively. Multivariable restricted cubic spline plots were developed to evaluate the functional form of the relationships. Among 3,598 KTRs, mean age was 52 ± 9 years, SBP was 136 ± 20 mm Hg, DBP was 79 ± 12 mm Hg, and eGFR was 49 ± 18 ml/minute/1.73 m2. There were 369 events of ≥50% eGFR decline or dialysis dependence during a mean follow-up of 4.0 ± 1.5 years. There was no association of either SBP (compared with SBP 120 to <130 mm Hg, hazard ratio (HR) for the SBP < 110 was 1.01 (95% confidence interval (CI) 0.60 to 1.70) and 130 to <140 was 0.89 (0.64 to 1.24)) or DBP (compared with DBP 70 to <80 mm Hg, HR for the DBP 60 to <70 was 1.00 (95% CI 0.74 to 1.34) and 80 to <90 was 0.90 (0.68 to 1.18)) with the kidney failure outcome or annualized eGFR slope, and, when examined using restricted cubic splines, there was no evidence of "J"- or "U"-shaped relationships. In a large sample of stable KTRs, we found no evidence of thresholds at which lower BPs were related to higher risk of allograft failure or eGFR decline. In light of prior findings of mortality benefit at low SBP, these observational findings suggest lower BP may be beneficial in KTRs. This important question requires confirmation in future randomized trials in KTRs.

Empagliflozin Improves Kidney Outcomes in Patients With or Without Heart Failure.

Background In EMPA-REG OUTCOME (Empagliflozin Cardiovascular Outcome Event Trial in Type 2 Diabetes Mellitus Patients) empagliflozin significantly reduced the risk of cardiovascular and kidney outcomes in patients with type 2 diabetes mellitus and established cardiovascular disease. Post hoc, we evaluated empagliflozin on kidney outcomes in patients with or without heart failure (HF). Methods and Results Individuals were randomized to empagliflozin 10 mg, 25 mg, or placebo. Prespecified analyses by baseline HF status included risk of incident or worsening nephropathy and estimated glomerular filtration rate slope analyses. Cox proportional hazards models assessed consistency of treatment effect across subgroups. Safety evaluations included kidney-related adverse events. At baseline, 244 (10.5%) and 462 (9.9%) patients had HF in the placebo and empagliflozin groups, respectively. Overall, the incidence of kidney outcome events was numerically higher in patients with than without HF. In the HF group, empagliflozin reduced risk of incident or worsening nephropathy or cardiovascular death by 43% (hazard ratio, 0.57 [95% CI, 0.42-0.77]) and progression to macroalbuminuria by 50% (hazard ratio, 0.50 [0.33-0.75]). After an initial transient decrease, estimated glomerular filtration rate stabilized over time with empagliflozin but gradually declined with placebo. Kidney effects in patients with HF were consistent with those in the overall study population (all P values for interaction >0.05). Across groups, the incidence rate of kidney-related adverse events/100 patient-years was higher in patients with than without HF; however, overall rates were comparable between groups. Conclusions These findings from EMPA-REG OUTCOME support the hypothesis that empagliflozin could reduce the risk of clinically relevant kidney events and may slow progression of chronic kidney disease in individuals with type 2 diabetes mellitus regardless of HF status. Clinical Trial Registration URL: https://www.clinicaltrials.gov . Unique identifier: NCT01131676.

Estimating glomerular filtration rate at the transition from pediatric to adult care

The current Kidney Disease Improving Global Outcomes (KDIGO) guidelines recommend the use of the bedside creatinine-based Chronic Kidney Disease in Children (CKiD) equation to estimate glomerular filtration rate (GFR) in children and the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation in adults. However, this approach causes implausible changes in estimated GFR (eGFR) at the transition from pediatric to adult care. We investigated the performance of the KDIGO strategy and various creatinine-based eGFR equations in a cross-sectional dataset of 5,764 subjects (age 10-30 years), using directly measured GFR (mGFR) as reference. We also evaluated longitudinal GFR slopes in 136 subjects who transitioned to adult care. Implausible changes in eGFR resulted from the large overestimation (bias=+21 mL/min/1.73m2) and poor precision of the CKD-EPI equation in the 18-20 year age group, compared to CKiD in the 16-18 year age group (bias=-2.7 mL/min/1.73m2), resulting in a mean change of 23 mL/min/1.73m2 at the transition to adult care. Averaging the CKiD and CKD-EPI estimates in young adults only partially mitigated this issue. The Full Age Spectrum equation (with and without height), the Lund-Malmö Revised equation, and an age-dependent weighted average of CKiD and CKD-EPI resulted in much smaller changes in eGFR at the transition (change of 0.6, -2.1, -0.9 and -1.8 mL/min/1.73m2, respectively). The longitudinal analysis revealed a significant difference in average GFR slope between mGFR and the KDIGO strategy (-2.2 vs.+2.9 mL/min/1.73 m2/year), which was not observed with the other approaches. These results suggest that the KDIGO recommendation for GFR estimation at the pediatric-adult care transition should be revisited.

Is there a correlation between an eGFR slope measured over a 5-year period and incident cardiovascular events in the following 5 years among a Flemish general practice population: a retrospective cohort study

ObjectivesTo examine if the estimated glomerular filtration rate (eGFR) slope over a 5-year period is related to incident cardiovascular (CV) events in the following 5 years.DesignRetrospective cohort study.SettingPrimary care.ParticipantsAll patients...

Age- and height-adjusted total kidney volume growth rate in autosomal dominant polycystic kidney diseases

BackgroundThe Mayo Clinic Image Classification (MIC) was proposed as a renal prognosis prediction model for autosomal dominant polycystic kidney disease (ADPKD). MIC is based on the assumption of exponential constant increase in height-adjusted total kidney volume (HtTKV). HtTKV growth rate is calculated by one-time measurement of HtTKV and age. We named it as an age-adjusted HtTKV growth rate (AHTKV-α). AHTKV-α was compared with HtTKV slope measured by at least two HtTKV values.MethodsComparison of repeatability between AHTKV-α and HtTKV slope, correlation of subgroups divided according to baseline AHTKV-α and HtTKV slope with disease manifestations, estimated glomerular filtration rate (eGFR) slope, and renal survival were analyzed in 296 patients with ADPKD. PKD genotype influences were compared between AHTKV-α and HtTKV slope in 88 patients with characterized PKD mutations.ResultsAbsolute differences between baseline and follow-up measures were significantly larger for the HtTKV slope than for AHTKV-α (P < 0.0001). From baseline AHTKV-α-based subgroups A–E according to MIC, disease manifestations occurred earlier and future eGFR slopes became steeper (P < 0.0001). Multivariate hazard ratios of renal survival differed significantly among baseline AHTKV-α-based subgroups. Inter-subgroup differences in these predictors were less evident during baseline HtTKV slope-based classification. AHTKV-α values, but not HtTKV slopes, were significantly higher for PKD1 mutation carriers than for PKD2 mutation carriers (P < 0.0001).ConclusionMIC is a good renal prediction model applicable to Japanese patients also. AHTKV-α can be a more sensitive and reliable indicator in TKV growth rate than HtTKV slope.