Improving precision in prediction: Using kidney failure risk equations as a potential adjunct to vascular access planning

Implications of Implementing the 2021 CKD-EPI Equation Without Race on Managing Patients With Kidney Disease in British Columbia, Canada

Introduction

We investigated the implications of implementing race-free Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) 2021 equation among real-world patients with chronic kidney disease (CKD) from British Columbia (BC), Canada.

Methods

This study included nondialysis-dependent patients with CKD aged ≥19 years who were registered in the Patient Records and Outcome Management Information System (PROMIS) as of March 31, 2016 (index date) with ≥1 serum creatinine measurement within 1 year before the index date. Patients with a history of kidney transplantation before the index date were excluded. CKD-EPI 2021 versus 2009 equation was the exposure variable. Difference in mean estimated glomerular filtration rate (eGFR) and number (%) of patients reclassified to a different eGFR category were estimated. We used Fine and Gray subdistribution hazard model to investigate the association between change in eGFR category and progression to kidney failure (incident maintenance dialysis or kidney transplantation) within 2 years.

Results

A total of 11,604 patients (median age 73 years, 52% male) were included. Compared to the 2009 equation, eGFR from 2021 equation was on average 2.7 ml/min per 1.73 m2 higher. Variation was higher among males. Overall, ∼17% of the study sample were reclassified to a category with higher eGFR by 2021 equation (switchers). The highest proportion (28%) of patients were reclassified from G5 to G4. The risk of progressing to kidney failure was 22% less among switchers compared to nonswitchers; adjusted subdistribution hazard ratio (HR) (95% confidence interval [CI]) is 0.78 (0.65, 0.94).

Conclusion

CKD-EPI 2021 equation appeared to provide higher eGFR compared to 2009 equation. This higher eGFR values appeared to be concordant with subsequent real-world CKD progression outcomes. Higher eGFR from the 2021 equation may have substantial clinical implications in both diagnosis as well as long-term care of patients with CKD.

Kidney Failure Risk Equation in vascular access planning: a population-based study supporting value in decision making

Background

The Kidney Failure Risk Equation (KFRE) can play a better role in vascular access (VA) planning in patients with chronic kidney disease (CKD) requiring hemodialysis (HD). We described the VA creation and utilization pattern under existing estimated glomerular filtration rate (eGFR)-based referral, and investigated the utility of KFRE score as an adjunct variable in VA planning.

Methods

Patients with CKD aged ≥18 years with eGFR <20 mL/min/1.73 m2 who chose HD as dialysis modality from January 2010 to August 2020 were included from a population-based database in British Columbia, Canada. Modality selection date was the index date. Exposures were categorized as (i) current eGFR-based referral, (ii) eGFR-based referral plus KRFE 2-year risk score on index date (KFRE-2) >40% and (iii) eGFR-based referral plus KFRE-2 ≤40%. We estimated the proportion of patients who started HD on arteriovenous fistula/graft (AVF/G) within 2 years, indicating timely pre-emptive creation, and the proportion of patients in whom AVF/G was created but did not start HD within 2 years, indicating too-early creation.

Results

Study included 2581 patients, median age 71 years, 60% male. Overall, 1562(61%) started HD and 276 (11%) experienced death before HD initiation within 2 years. Compared with current referral, the proportion of patients who started HD on AVF/G was significantly higher when KFRE-2 was considered in addition to current referral (49% vs 58%, P-value <.001). Adjunct KFRE-2 significantly reduced too-early creation (31% vs 18%, P-value <.001).

Conclusions

KFRE in addition to existing eGFR-based referral for VA creation has the potential to improve VA resource utilization by ensuring more patients start HD on AVF/G and may minimize too-early/unnecessary creation. Prospective research is necessary to validate these findings.

Implementing a Formalized Risk-Based Approach to Determine Candidacy for Multidisciplinary CKD Care: A Descriptive Cohort Study

Background

The kidney failure risk equation (KFRE) can be used to predict progression to end-stage kidney disease in a clinical setting.

Objective

Evaluate implementation of a formalized risk-based approach in nephrologists' outpatient clinics and multidisciplinary chronic kidney disease (CKD) clinics to determine candidacy for multidisciplinary care, and the impact of CKD care selection on clinical outcomes.

Design

Population-based descriptive cohort study.

Setting

Alberta Kidney Care South.

Patients

Adults attending or considered for a multidisciplinary CKD clinic between April 1, 2017, and March 31, 2019.

Measurements

Exposure-The course of CKD care assigned by the nephrologist: management at multidisciplinary CKD clinic; management by a nephrologist or primary care physician. Primary Outcome-CKD progression, defined as commencement of kidney replacement therapy (KRT). Secondary Outcomes-Death, emergency department visits, and hospitalizations.

Methods

We linked operational data from the clinics (available until March 31, 2019) with administrative health and laboratory data (available until March 31, 2020). Comparisons among patient groups, courses of care, and clinical settings with negative binomial regression count models and calculated unadjusted and fully adjusted incidence rate ratios. For the all-cause death outcome, we used Cox survival models to calculate unadjusted and fully adjusted hazard ratios.

Results

Of the 1748 patients for whom a KFRE was completed, 1347 (77%) remained in or were admitted to a multidisciplinary CKD clinic, 310 (18%) were managed by a nephrologist only, and 91 (5%) were referred back for management by their primary care physician. There was a much higher kidney failure risk among patients who remained at or were admitted to a multidisciplinary CKD clinic (median 2-year risk of 34.7% compared with 3.6% and 0.8% who remained with a nephrologist or primary care physician, respectively). None of the people managed by their primary care physician alone commenced KRT, while only 2 (0.6%) managed by a nephrologist without multidisciplinary CKD care commenced KRT. The rates of emergency department visits, hospitalizations, and death were lower in those assigned to management outside the multidisciplinary CKD clinics when compared with those managed in the multidisciplinary care setting.

Limitations

The follow-up period may not have been long enough to determine outcomes, and potentially limited generalizability given variability of care in multidisciplinary clinics.

Conclusions

Our findings indicate that a portion of patients can be directed to less resource-intensive care without a higher risk of adverse events.

Trial registration

Not applicable.

Tunnelled central venous catheters for incident haemodialysis patients: a Victorian survey exploring reasons for use

BACKGROUND

Tunnelled central venous catheters (T-CVCs) are used globally as vascular access for patients on haemodialysis (HD) but are associated with increased sepsis, mortality, cost and length of hospitalisation compared with more permanent HD vascular access. The reasons for using T-CVC are varied and poorly understood. A significant and increasing proportion of incident HD patients in Victoria, Australia, have required T-CVC over the last decade.

AIM

To explore reasons for a significant and increasing proportion of incident HD patients in Victoria, Australia, having required T-CVC over the last decade.

METHODS

With rates of starting HD with definitive vascular access consistently below a Victorian quality indicator target of 70%, an online survey was developed to explore reasons why the rate remained lower than desired and to help inform future decisions about this quality indicator. The survey was completed by dialysis access coordinators over an 8-month period and involved all public nephrology services in Victoria.

RESULTS

Of the 125 surveys completed, 101 incident HD patients had no attempt at permanent vascular access prior to T-CVC insertion. For almost half of these (48 patients), there was no active medical decision not to create permanent vascular access prior to commencing dialysis. Reasons for insertion of the T-CVC included deterioration of kidney function faster than anticipated, surgical referral being overlooked, complications related to peritoneal dialysis requiring a change in dialysis modality and changes to initial decisions regarding dialysis modality for kidney failure.

CONCLUSIONS

These survey results provide an opportunity for quality improvement initiatives with respect to dialysis access planning and care.

Radiocephalic Arteriovenous Fistula Patency and Use

We sought to confirm and extend the understanding of clinical outcomes following creation of a common distal autogenous access, the radiocephalic arteriovenous fistula (RCAVF).

Mini-abstract: In this post hoc analysis of randomized clinical trial data including 914 adults with chronic kidney disease, the most robust predictors of radiocephalic arteriovenous fistula patency were larger cephalic vein diameter and access creation prior to a chronic hemodialysis requirement. Successful use occurred at increased rates in men, patients with larger diameter cephalic veins, smaller diameter arteries (albeit ≥2 mm), and when accesses were created using regional anesthesia and at higher volume centers.

Use of the kidney failure risk equation to inform clinical care of patients with chronic kidney disease: a mixed-methods systematic review

RATIONALE AND OBJECTIVE

The Kidney Failure Risk Equation (KFRE) predicts the risk of end-stage kidney disease in patients with chronic kidney disease (CKD). This study aimed to evaluate the impact of the utility of KFRE in clinical practice.

STUDY DESIGN

Systematic review.

SETTING AND STUDY POPULATIONS

Adult patients with CKD but not receiving renal replacement therapy enrolled in studies where KFRE was used in clinical care pathways.

SELECTION CRITERIA FOR STUDIES

All studies published from April 2011 to October 2021 identified from Medline, Cumulative Index to Nursing and Allied Health Literature, Embase and reference and citation searches of included studies.

DATA EXTRACTION

Relevant data were extracted, and two reviewers independently assessed study quality using appropriate appraisal tools.

ANALYTICAL APPROACH

Findings reported as a narrative synthesis due to heterogeneity of the included studies.

RESULTS

Of 1635 studies identified, 440 duplicates were removed. The remaining 1195 titles and abstracts were screened. All five studies for full-text review were included in the analysis. Three uses of KFRE were assessed: (1) primary to specialty care interface; (2) general nephrology to multidisciplinary care transition; and (3) treatment planning. Evidence of impact on number of patient referrals into nephrology care was conflicting. However, wait times improved in one study. Although KFRE identified high-risk patients for increased multidisciplinary support, there was concern patients stepped down, no longer meeting eligibility criteria, may lack access to services.

CONCLUSIONS

This is the first systematic review of studies that have assessed the actual impact of KFRE in clinical practice with five studies of varying quality reported to date. Trials are in progress assessing the impact on clinical outcomes of using KFRE in clinical practice, and KFRE is being incorporated into guidelines for CKD management. Further studies are needed to assess the impact of KFRE on clinical care.

TRIAL REGISTRATION NUMBER

Protocol registered on PROSPERO before initiation of the study (Ref: CRD42020219926).

Targeting Patient and Health System Barriers To Improve Rates of Hemodialysis Initiation with an Arteriovenous Access

Background

Guidelines recommend pre-emptive creation of arteriovenous (AV) access. However, <20% of US patients initiate hemodialysis (HD) with a functional AV access. We implemented a quality improvement (QI) program to improve pre-HD vascular access care.

Methods

After conducting qualitative research with key informants, we implemented a 7-month vascular access support QI program at Geisinger Health. The program targeted patient and health system barriers to AV access through education, needs assessment, peer support, care navigation, and electronic supports. We performed pre-, intra-, and postprogram stakeholder interviews to identify program barriers and facilitators and to assess acceptability. In a research substudy, we compared pre- and postprogram self-efficacy, knowledge, and confidence navigating vascular access care.

Results

There were 37 patient and 32 clinician/personnel participants. Of the 37 patients, 34 (92%) completed vascular access-specific education, 33 (89%) underwent needs assessment, eight (22%) engaged with peer mentors, 21 (57%) had vein mapping, 18 (49%) had an initial surgical appointment, 15 (40%) underwent AV access surgery, and six (16%) started HD during the 7-month program. Qualitative findings demonstrated program acceptability to participants and suggested that education provision and emotional barrier identification were important to engaging patients in vascular access care. Research findings showed pre- to postprogram improvements in patient self-efficacy (28.1-30.8, P=0.05) and knowledge (4.9-6.9, P=0.004), and trends toward improvements in confidence among patients (8.0-8.7, P=0.2) and providers (7.5-7.8, P=0.1).

Conclusions

Our intervention targeting patient and health system barriers improved patient vascular access knowledge and self-efficacy.

Clinical Trial registry name and registration number

Breaking Down Care Process and Patient-level Barriers to Arteriovenous Access Creation Prior to Hemodialysis Initiation, NCT04032613.

Estimating Kidney Failure Risk Using Electronic Medical Records

Background

The four-variable kidney failure risk equation (KFRE) is a well-validated tool for patients with GFR <60 ml/min per 1.73 m² and incorporates age, sex, GFR, and urine albumin-creatinine ratio (ACR) to forecast individual risk of kidney failure. Implementing the KFRE in electronic medical records is challenging, however, due to low ACR testing in clinical practice. The aim of this study was to determine, when ACR is missing, whether to impute ACR from protein-to-creatinine ratio (PCR) or dipstick protein for use in the four-variable KFRE, or to use the three-variable KFRE, which does not require ACR.

Methods

Using electronic health records from OptumLabs Data Warehouse, patients with eGFR <60 ml/min per 1.73 m² were categorized on the basis of the availability of ACR testing within the previous 3 years. For patients missing ACR, we extracted urine PCR and dipstick protein results, comparing the discrimination of the three-variable KFRE (age, sex, GFR) with the four-variable KFRE estimated using imputed ACR from PCR and dipstick protein levels.

Results

There were 976,299 patients in 39 health care organizations; 59% were women, the mean age was 72 years, and mean eGFR was 47 ml/min per 1.73 m². The proportion with ACR testing was 19% within the previous 3 years. An additional 2% had an available PCR and 36% had a dipstick protein; the remaining 43% had no form of albuminuria testing. The four-variable KFRE had significantly better discrimination than the three-variable KFRE among patients with ACR testing, PCR testing, and urine dipstick protein levels, even with imputed ACR for the latter two groups. Calibration of the four-variable KFRE was acceptable in each group, but the three-variable equation showed systematic bias in the groups that lacked ACR or PCR testing.

Conclusions

Implementation of the KFRE in electronic medical records should incorporate ACR, even if only imputed from PCR or urine dipstick protein levels.

Predicted risk of renal replacement therapy at arteriovenous fistula referral in chronic kidney disease

BACKGROUND AND OBJECTIVES

Optimal timing of arteriovenous fistula placement in chronic kidney disease remains difficult and contributes to high central venous catheter use at initial hemodialysis. We tested whether a prediction model for progression to renal replacement therapy developed at Kaiser Permanente Northwest may help guide decisions about timing of referral for arteriovenous fistula placement.

DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS

A total of 205 chronic kidney disease stage 4 patients followed by nephrology referred for arteriovenous fistula placement were followed for up to 2 years. Patients were censored if they died or discontinued Kaiser Permanente Northwest coverage. Survival analyses were performed for overall progression to renal replacement therapy divided by quartiles based on 2-year risk for renal replacement therapy and estimated glomerular filtrate rate at time of referral.

RESULTS

By 2 years, 60% progressed to renal replacement therapy and 11% had died. 80% in the highest risk versus 36% in the lowest risk quartile progressed to renal replacement therapy (predicted risk 84% vs 17%). 75% in the lowest estimated glomerular filtrate rate versus 56% in the highest estimated glomerular filtrate rate quartile progressed to renal replacement therapy (mean estimated glomerular filtrate rate 13 mL/min vs 21 mL/min). The hazard ratio was significantly higher for each consecutive higher renal replacement therapy quartile risk while for estimated glomerular filtrate rate, the hazard ratio was only significantly higher for the lowest compared to the highest quartile. The extreme quartile risk ratio was higher for 2-year risk for renal replacement therapy compared to estimated glomerular filtrate rate (4.0 vs 2.4).

CONCLUSION

In patients with chronic kidney disease stage 4 referred for arteriovenous fistula placement, 2-year renal replacement therapy risk better discriminated progression to renal replacement therapy compared to estimated glomerular filtrate rate at time of referral.

Integrating Risk-Based Care for Patients With Chronic Kidney Disease in the Community: Study Protocol for a Cluster Randomized Trial

Background:

A risk-based model of care for managing patients with chronic kidney disease (CKD) using the Kidney Failure Risk Equation (KFRE) has been successfully integrated into nephrology care pathways in several jurisdictions. However, as most patients with CKD can be managed in primary care, the next pertinent steps would be to integrate the KFRE into primary care pathways.

Objective:

Using a risk-based approach for guiding CKD care in the primary care setting, the objective of the study is to develop, implement, and evaluate tools that can be used by patients and providers.

Design:

This study is a multicenter cluster randomized control trial.

Setting:

Thirty-two primary care clinics belonging to the Canadian Primary Care Sentinel Surveillance Network (CPCSSN) across Manitoba and Alberta.

Patients:

All patients at least 18 years old or older with CKD categories G3-G5 attending the participating clinics; we estimate each clinic will have an average of 185 patients with CKD.

Methods:

Thirty-two primary care clinics will be randomized to receive either an active knowledge translation intervention or no intervention. The intervention involves the addition of the KFRE and decision aids to clinics’ Data Presentation Tool (DPT), as well as patient-facing visual aids, a medical detailing visit, and sentinel feedback reports. Control clinics will only be exposed to current guidelines for CKD management, without active dissemination.

Measurements:

Data from the CPCSSN repository will be used to assess whether a risk-based care approach affected management of CKD. Primary outcomes are as follows: the proportion of patients with measured urine albumin-to-creatinine ratio, and the proportion of patients being appropriately treated with angiotensin-converting enzyme inhibitor or angiotensin receptor blockers. Secondary outcomes are as follows: the optimal management of diabetes (hemoglobin A1C <8.5%, and the use of sodium-glucose cotransporter-2 inhibitors in CKD G3 patients), hypertension (office blood pressure <130/80 for patients with diabetes, 140/90 for those without), and cardiovascular risk (statin prescription); prescriptions of nonsteroidal anti-inflammatory drugs; and decline in estimated glomerular filtration rate (eGFR). In addition, in a substudy, we will measure CKD-specific health literacy and trust in physician care via surveys administered in the clinic post-visit. At the provider level, we will measure satisfaction with the risk prediction tools. Lastly, at the health system level, outcomes include cost of CKD care, and appropriate referrals for patients at high risk of kidney failure based on provincial guidelines. Primary and secondary outcomes will be measured at the patient level and enumerated at the clinic level 1 year after the intervention implementation, except for decline in eGFR, which will be measured 2 years postintervention.

Limitations:

Limitations include scalability of the proposal in other health care systems.

Conclusions:

If successful, this intervention has the potential to improve the management of patients with CKD within Canadian primary care settings, leading to health and economic benefits, and influencing practice guidelines.

Trial Registration:

ClinicalTrials.gov identifier: NCT03365063

Arteriovenous conduits for hemodialysis: how to better modulate the pathophysiological vascular response to optimize vascular access durability

Vascular access is the lifeline for patients on hemodialysis. Arteriovenous fistulas (AVFs) are the preferred vascular access, but AVF maturation failure remains a significant clinical problem. Currently, there are no effective therapies available to prevent or treat AVF maturation failure. AVF maturation failure frequently results from venous stenosis at the AVF anastomosis, which is secondary to poor outward vascular remodeling and excessive venous intimal hyperplasia that narrows the AVF lumen. Arteriovenous grafts (AVGs) are the next preferred vascular access when an AVF creation is not possible. AVG failure is primarily the result of venous stenosis at the vein-graft anastomosis, which originates from intimal hyperplasia development. Although there has been advancement in our knowledge of the pathophysiology of AVF maturation and AVG failure, this has not translated into effective therapies for these two important clinical problems. Further work will be required to dissect out the mechanisms of AVF maturation failure and AVG failure to develop more specific therapies. This review highlights the major recent advancements in AVF and AVG biology, reviews major clinical trials, and discusses new areas for future research.