Association between Acute Declines in Estimated Glomerular Filtration Rate during Renin-Angiotensin System Inhibition and Risk of Adverse Outcomes.

BACKGROUND: Declines in glomerular filtration rate (GFR) occur commonly when renin-angiotensin system (RAS) inhibitors are started. Our objective was to determine the relation between declines in estimated GFR during trials of RAS inhibition and kidney outcomes. METHODS: We included participants with CKD (estimated GFR<60 mL/min/1.73m2) from 16 trials of RAS inhibition. The exposure was subacute declines in estimated GFR expressed as % change between randomization and month 3, and in the subset of trials with data available, we also examined % change in eGFR between randomization and month 1. The primary outcome was kidney failure with replacement therapy. Cox proportional hazards models were used to examine the association between subacute declines in eGFR and risk of kidney failure. We used spline models to identify the threshold of change in eGFR below which RAS inhibition was favorable (conservatively comparing a given decline in eGFR with RAS inhibition to no decline in the comparator). RESULTS: 11,800 individuals with mean eGFR 43 (SD 11) mL/min/1.73m2 and median urine albumin/creatinine ratio of 362 mg/g (IQR 50, 1367) were included, and 1,162 (10%) developed kidney failure. The threshold of decline in eGFR that favored use of RAS inhibitors for kidney failure was estimated to be up to 13% (95%CI 8%, 17%) over a 3-month interval and up to 21% (95%CI 15%, 27%) over a 1-month interval after starting RAS inhibitors. CONCLUSIONS: In people treated with RAS inhibitors, ≤ 13% decline in eGFR over a 3-month period or ≤21% decline over a 1-month period was associated with lower risk of kidney failure compared with no decline with the use of placebo or other agents.

Transient albuminuria in the setting of short-term severe hyperglycemia in type 1 diabetes.

In a cohort of 1817 children with type 1 diabetes (T1D), short-term hyperglycemia was associated with transient albuminuria (11 % during new-onset T1D without diabetic ketoacidosis (DKA), 12 % during/after DKA, 6 % during routine screening). Our findings have implications regarding future risk of diabetic kidney disease and further investigation is needed.

Use of activity trackers to improve blood pressure in young people at risk for cardiovascular disease: a pilot randomized controlled trial.

BACKGROUND: Promoting physical activity among young individuals with cardiovascular disease (CVD) risk factors such as hypertension, diabetes, or chronic kidney disease can lower systolic blood pressure (BP). We sought to determine whether a 6-month intervention using a physical activity tracker was feasible and effective, compared with usual care. METHODS: Participants were recruited at a single academic medical center. Those aged 8-30 years were randomized in a 2:1 ratio to either the intervention (use of a Fitbit physical activity tracker coupled with feedback regarding the participant's step count) or usual care. The primary feasibility outcomes were screening-to-enrollment ratio and 6-month retention rates; the primary clinical outcome was a change in systolic BP from 0-6 months. RESULTS: Sixty-three participants were enrolled (57% male; mean age: 18 ± 4 years). The screening-to-enrollment ratio was 1.8:1. Six-month retention was 62% in the intervention group and 86% in the control group (p = 0.08). Mean change in systolic BP in the intervention group was not significantly different from the control group at 6 months (- 2.3 mmHg; 95% CI - 6.5, 1.8 vs. 3.0 mmHg; 95% CI - 2.5, 8.4, respectively, p = 0.12). CONCLUSIONS: Among children and young adults at elevated CVD risk, the use of a physical activity tracker coupled with tailored feedback regarding their step count progress was feasible but not sustained over time. Physical activity tracker use did not have a statistically significant effect on BP after 6 months. Augmented strategies to mitigate risk in young patients at high risk for early-onset CVD should be explored. This trial is registered at ClinicalTrials.gov (NCT03325426).

Strategies to Guide Preemptive Waitlisting and Equity in Waittime Accrual by Race/Ethnicity.

BACKGROUND: Use of eGFR to determine preemptive waitlisting eligibility may contribute to racial/ethnic disparities in access to waitlisting, which can only occur when the eGFR falls to ≤20 ml/min per 1.73 m 2 . Use of an alternative risk-based strategy for waitlisting may reduce these inequities ( e.g. , a kidney failure risk equation [KFRE] estimated 2-year risk of kidney failure) rather than the standard eGFR threshold for determining waitlist eligibility. Our objective was to model the amount of preemptive waittime that could be accrued by race and ethnicity, applying two different strategies to determine waitlist eligibility. METHODS: Using electronic health record data, linear mixed models were used to compare racial/ethnic differences in preemptive waittime that could be accrued using two strategies: estimating the time between an eGFR ≤20 and 5 ml/min per 1.73 m 2 versus time between a 25% 2-year predicted risk of kidney failure (using the KFRE, which incorporates age, sex, albuminuria, and eGFR to provide kidney failure risk estimation) and eGFR of 5 ml/min per 1.73 m 2 . RESULTS: Among 1290 adults with CKD stages 4-5, using the Chronic Kidney Disease Epidemiology Collaboration equation yielded shorter preemptive waittime between an eGFR of 20 and 5 ml/min per 1.73 m 2 in Black (-6.8 months; 95% confidence interval [CI], -11.7 to -1.9), Hispanic (-10.2 months; -15.3 to -5.1), and Asian/Pacific Islander (-10.3 months; 95% CI, -15.3 to -5.4) patients compared with non-Hispanic White patients. Use of a KFRE threshold to determine waittime yielded smaller differences by race and ethnicity than observed when using a single eGFR threshold, with shorter time still noted for Black (-2.5 months; 95% CI, -7.8 to 2.7), Hispanic (-4.8 months; 95% CI, -10.3 to 0.6), and Asian/Pacific Islander (-5.4 months; -10.7 to -0.1) individuals compared with non-Hispanic White individuals, but findings only met statistical significance criteria in Asian/Pacific Islander individuals. When we compared potential waittime availability using a KFRE versus eGFR threshold, use of the KFRE yielded more equity in waittime for Black ( P = 0.02), Hispanic ( P = 0.002), and Asian/Pacific Islander ( P = 0.002) patients. CONCLUSIONS: Use of a risk-based strategy was associated with greater racial equity in waittime accrual compared with use of a standard single eGFR threshold to determine eligibility for preemptive waitlisting.

Peritoneal Dialysis Catheter Complications after Insertion by Surgeons, Radiologists, or Nephrologists.

SIGNIFICANCE STATEMENT: The Advancing American Kidney Health Initiative aims to increase rates of utilization of peritoneal dialysis (PD) in the United States. One of the first steps to PD is successful catheter placement, which can be performed by surgeons, interventional radiologists, or nephrologists. We examined the association between operator subspecialty and risk of needing a follow-up procedure in the first 90 days after initial PD catheter implantation. Overall, we found that 15.5% of catheters required revision, removal, or a second catheter placement within 90 days. The odds of requiring a follow-up procedure was 36% higher for interventional radiologists and 86% higher for interventional nephrologists compared with general surgeons. Further research is needed to understand how to optimize the function of catheters across different operator types. BACKGROUND: The US government has implemented incentives to increase the use of PD. Successful placement of PD catheters is an important step to increasing PD utilization rates. Our objective was to compare initial outcomes after PD catheter placement by different types of operators. METHODS: We included PD-naïve patients insured by Medicare who had a PD catheter inserted between 2010 and 2019. We examined the association between specialty of the operator (general surgeon, vascular surgeon, interventional radiologist, or interventional nephrologist) and odds of needing a follow-up procedure, which we defined as catheter removal, replacement, or revision within 90 days of the initial procedure. Mixed logistic regression models clustered by operator were used to examine the association between operator type and outcomes. RESULTS: We included 46,973 patients treated by 5205 operators (71.1% general surgeons, 17.2% vascular surgeons, 9.7% interventional radiologists, 2.0% interventional nephrologists). 15.5% of patients required a follow-up procedure within 90 days of the initial insertion, of whom 2.9% had a second PD catheter implanted, 6.6% underwent PD catheter removal, and 5.9% had a PD catheter revision within 90 days of the initial insertion. In models adjusted for patient and operator characteristics, the odds of requiring a follow-up procedure within 90 days were highest for interventional nephrologists (HR, 1.86; 95% confidence interval [CI], 1.56 to 2.22) and interventional radiologists (odds ratio, 1.36; 95% CI, 1.17 to 1.58) followed by vascular surgeons (odds ratio, 1.06; 95% CI, 0.97 to 1.14) compared with general surgeons. CONCLUSIONS: The probability of needing a follow-up procedure after initial PD catheter placement varied by operator specialty and was higher for interventionalists and lowest for general surgeons.

Rurality of patient residence and access to transplantation among children with kidney failure in the United States.

BACKGROUND: Residence in rural areas is often a barrier to health care access. To date, differences in access to kidney transplantation among children who reside in rural and micropolitan areas of the US have not been explored. METHODS: A retrospective cohort study of children < 18 years who developed kidney failure between 2000 and 2019 according to the United States Renal Data System (USRDS). We examined the association between rurality of patient residence and time to living and/or deceased donor kidney transplantation (primary outcomes) and waitlist registration (secondary outcome) using Fine-Gray models. RESULTS: We included 18,530 children, of whom 14,175 (76.5%) received a kidney transplant (39.8% from a living and 60.2% from a deceased donor). Residence in micropolitan (subhazard ratio (SHR) 1.16; 95% CI 1.06-1.27) and rural (SHR 1.18; 95% CI 1.06-1.3) areas was associated with better access to living donor transplantation compared with residence in metropolitan areas. There was no statistically significant association between residence in micropolitan (SHR, 0.95; 95%CI 0.88-1.03) and rural (SHR, 0.94; 95%CI 0.86-1.03) areas compared with metropolitan areas in the access of children to deceased donor transplantation. There was also no difference in the time to waitlist registration comparing micropolitan (SHR 1.04; 95%CI 0.98-1.10) and rural (SHR 1.05; 95% CI 0.98-1.13) versus metropolitan areas. CONCLUSIONS: In children with kidney failure, residence in rural and micropolitan areas was associated with better access to living donor transplantation and similar access to deceased donor transplantation compared with residence in metropolitan areas.

Association Between Dialysis Facility Ownership and Mortality Risk in Children With Kidney Failure.

Importance: In adults, treatment at profit dialysis facilities has been associated with a higher risk of death. Objective: To determine whether profit status of dialysis facilities is associated with the risk of death in children with kidney failure treated with dialysis and whether any such association is mediated by differences in access to transplant. Design, Setting, and Participants: This retrospective cohort study reviewed US Renal Data System records of 15 359 children who began receiving dialysis for kidney failure between January 1, 2000, and December 31, 2019, in US dialysis facilities. The data analysis was performed between May 2, 2022, and June 15, 2023. Exposure: Time-updated profit status of dialysis facilities. Main Outcomes and Measures: Adjusted Fine-Gray models were used to determine the association of time-updated profit status of dialysis facilities with risk of death, treating kidney transplant as a competing risk. Cox proportional hazards regression models were also used to determine time-updated profit status with risk of death regardless of transplant status. Results: The final cohort included 8465 boys (55.3%) and 6832 girls (44.7%) (median [IQR] age, 12 [3-15] years). During a median follow-up of 1.4 (IQR, 0.6-2.7) years, with censoring at transplant, the incidence of death was higher at profit vs nonprofit facilities (7.03 vs 4.06 per 100 person-years, respectively). Children treated at profit facilities had a 2.07-fold (95% CI, 1.83-2.35) higher risk of death compared with children at nonprofit facilities in adjusted analyses accounting for the competing risk of transplant. When follow-up was extended regardless of transplant status, the risk of death remained higher for children treated in profit facilities (hazard ratio, 1.47; 95% CI, 1.35-1.61). Lower access to transplant in profit facilities mediated 67% of the association between facility profit status and risk of death (95% CI, 45%-100%). Conclusions and Relevance: Given the higher risk of death associated with profit dialysis facilities that is partially mediated by lower access to transplant, the study's findings indicate a need to identify root causes and targeted interventions that can improve mortality outcomes for children treated in these facilities.

Acute Declines in Estimated GFR in Blood Pressure Target Trials and Risk of Adverse Outcomes.

RATIONALE & OBJECTIVE: Acute decreases in glomerular filtration rate (GFR) occur commonly during intensive blood pressure (BP) lowering. Our objective was to determine the relationship between acute decreases in estimated GFR and patient outcomes. STUDY DESIGN: Retrospective observational study. SETTING & PARTICIPANTS: Participants from 4 randomized controlled trials of intensive BP lowering in chronic kidney disease (Modification of Diet in Renal Disease study, African American Study of Kidney Disease and Hypertension, Systolic Blood Pressure Intervention Trial, and Action to Control Cardiovascular Risk in Diabetes trial). EXPOSURE: A 4-category exposure defined by the level of acute decrease in estimated GFR (defined as>15% vs≤15% between baseline and month 4) and the randomization to intensive versus usual BP control. OUTCOMES: Risk of kidney replacement therapy (primary outcome), defined as the need for dialysis or transplant except in the Action to Control Cardiovascular Risk in Diabetes trial, which defined its kidney outcome as a composite occurrence of serum creatinine concentration>3.3mg/dL, kidney failure, or kidney replacement therapy. ANALYTICAL APPROACH: Multivariable Cox models. RESULTS: We included 4,473 individuals randomly assigned to intensive versus usual BP control who had a total of 351 kidney outcomes and 304 deaths during median follow-up durations of 22 and 24 months, respectively. Approximately 14% of participants exhibited an acute decrease in eGFR, 11.0% in the usual BP treatment arm and 17.8% in the intensive BP treatment arm. In adjusted models, compared with a≤15% eGFR decrease in the usual BP arm, a≤15% eGFR decrease in the intensive BP control arm was associated with lower risk of the kidney outcome (HR, 0.75; 95% CI, 0.57-0.98). In contrast, a>15% decrease in eGFR was associated with a higher risk of the kidney outcome in the usual (HR, 2.47; 95% CI, 1.80-3.38) and intensive BP treatment arms (HR, 1.99; 95% CI, 1.45-2.73) compared with a≤15% decrease in the usual BP arm. LIMITATIONS: Observational study, residual confounding. CONCLUSIONS: Decreases in eGFR of>15% in the usual and intensive BP treatment arms were associated with a higher risk of kidney outcomes compared with a≤15% decrease in the usual BP arm and may be a harbinger of adverse outcomes.

Novel anemia therapies in chronic kidney disease: conclusions from a Kidney Disease: Improving Global Outcomes (KDIGO) Controversies Conference.

Anemia is common in patients with chronic kidney disease and is associated with a high burden of morbidity and adverse clinical outcomes. In 2012, Kidney Disease: Improving Global Outcomes (KDIGO) published a guideline for the diagnosis and management of anemia in chronic kidney disease. Since then, new data from studies assessing established and emerging therapies for the treatment of anemia and iron deficiency have become available. Beginning in 2019, KDIGO planned 2 Controversies Conferences to review the new evidence and its potential impact on the management of anemia in clinical practice. Here, we report on the second of these conferences held virtually in December 2021, which focused on a new class of agents-the hypoxia-inducible factor-prolyl hydroxylase inhibitors (HIF-PHIs). This report provides a review of the consensus points and controversies from this second conference and highlights areas that warrant prioritization for future research.

Intensive BP Control in Patients with CKD and Risk for Adverse Outcomes.

SIGNIFICANCE STATEMENT: Although most guidelines recommend tightly controlling BP in patients with CKD, individuals with advanced kidney disease or severe albuminuria were not well-represented in trials examining the effect of this intervention on kidney outcomes. To examine the effect of intensive BP control on the risk of kidney outcomes in patients with CKD, the authors pooled individual-level data from seven trials. They found that overall, intensive BP control was associated with a 13% lower, but not significant, risk of a kidney outcome. However, the intervention's effect on the kidney outcome differed depending on baseline eGFR. Data from this pooled analysis suggested a benefit of intensive BP control in delaying KRT onset in patients with stages 4-5 CKD, but not necessarily in those with stage 3 CKD. BACKGROUND: The effect of intensive BP lowering (to systolic BP of <120 mm Hg) on the risk of kidney failure requiring KRT remains unclear in patients with advanced CKD. Such patients were not well represented in trials evaluating intensive BP control. METHODS: To examine the effect of intensive BP lowering on KRT risk-or when not possible, trial-defined kidney outcomes-we pooled individual-level data from seven trials that included patients with eGFR<60 ml/min per 1.73 m 2 . We performed prespecified subgroup analyses to evaluate the effect of intensive BP control by baseline albuminuria and eGFR (CKD stages 4-5 versus stage 3). RESULTS: Of 5823 trial participants, 526 developed the kidney outcome and 382 died. Overall, intensive (versus usual) BP control was associated with a lower risk of kidney outcome and death in unadjusted analyses but these findings did not achieve statistical significance. However, the intervention's effect on the kidney outcome differed depending on baseline eGFR ( P interaction=0.05). By intention-to-treat analysis, intensive (versus usual) BP control was associated with a 20% lower risk of the primary kidney outcome in those with CKD GFR stages 4-5, but not in CKD GFR stage 3. There was no interaction between intensive BP control and the severity of albuminuria for kidney outcomes. CONCLUSIONS: Data from this pooled analysis of seven trials suggest a benefit of intensive BP control in delaying KRT onset in patients with stages 4-5 CKD but not necessarily with stage 3 CKD. These findings suggest no evidence of harm from intensive BP control, but also point to the need for future trials of BP targets focused on populations with advanced kidney disease. PODCAST: This article contains a podcast at https://dts.podtrac.com/redirect.mp3/www.asn-online.org/media/podcast/JASN/2023_02_27_JASN0000000000000060.mp3.