Pain and Health-Related Quality of Life in Autosomal Dominant Polycystic Kidney Disease: Results from a National Patient-Powered Registry.

Rationale & Objective: Autosomal dominant polycystic kidney disease (ADPKD) affects health-related quality of life (HRQoL) including pain, discomfort, fatigue, emotional distress, and impaired mobility. Stakeholders prioritized kidney cyst-related pain as an important core outcome domain in clinical trials, leading to the development of disease-specific assessment tools. Study Design: The ADPKD Registry is hosted online with multiple disease-specific patient-reported outcomes modules to characterize the patient experience in the United States. Setting & Participants: The ADPKD Registry allows consented participants access to a Core Questionnaire that includes demographics, comorbid conditions, current symptoms, and kidney function. Participants complete subsequent modules on a 3-month schedule, including 2 validated HRQoL tools, the ADPKD-Pain and Discomfort Scale (ADPKD-PDS), the ADPKD Impact Scale (ADPKD-IS) and a Healthcare Access and Utilization module. Exposures: Patient-reported latest estimated glomerular filtration rate or creatinine used to calculate stage of chronic kidney disease. Outcomes: Health-related quality of life, measured using validated ADPKD-specific tools; access to polycystic kidney disease-specific health care. Analytical Approach: For the 2 HRQoL tools, scores were calculated for physical, emotional, and fatigue domains; pain severity; and pain interference (based on the licensed user manuals). Associations to health care access were also assessed. Results: By July 2022, 1,086 individuals with ADPKD completed at least 1 of the HRQoL modules, and 319 completed 4 over a year. Participants were an average age of 53. In total, 71% were women, and 91% were White, with all chronic kidney disease (CKD) stages represented. In total, 2.5% reported being treated with dialysis, and 23% had a kidney transplant. CKD stage 4/5 participants reported the most dull kidney pain, whereas sharp kidney pain was evenly distributed across early CKD stages. Dull kidney pain had an impact on sleep regardless of CKD stage. There was a strong positive correlation between the ADPKD-PDS and ADPKD-IS. Patients with a neutral or positive HRQoL were less likely to have been denied access to imaging or other care. Limitations: Currently, all the information collected is patient reported without health record validation of clinical variables. Conclusions: Use of the HRQoL tools in the ADPKD Registry provided a broad cross-sectional assessment in the United States and provided granular information on the burden of pain across the CKD spectrum in ADPKD. The ADPKD Registry allowed assessment of ADPKD impact in a community that experiences decline in health and kidney function over decades.

The Autosomal Dominant Polycystic Kidney Disease Registry is a longitudinal, patient-powered research tool created with the goal to better understand the impacts of ADPKD on affected individuals in the United States. Here, we analyze pain and other health-related quality of life outcomes in 1,086 individuals using validated tools and comment on the utility of these tools for future use in clinical trials and observational studies. We found that sharp pain, dull pain, fullness discomfort, and other related impacts affected individuals across the disease spectrum, although some participants reported more dull pain in later stages (CKD stages 4 and 5). Future analysis of these trends over time will be valuable in understanding how to assess and address the burden of pain in autosomal dominant polycystic kidney disease.

Potential Mediators for Treatment Effects of Novel Diabetes Medications on Cardiovascular and Renal Outcomes: A Meta-Regression Analysis.

BACKGROUND: Prior research suggests clinical effects of glucagon-like peptide-1 receptor agonists (GLP-1RAs) and sodium-glucose cotransporter-2 inhibitors (SGLT2is) are mediated by changes in glycated hemoglobin, body weight, systolic blood pressure, hematocrit, and urine albumin-creatinine ratio. We aimed to confirm these findings using a meta-analytic approach. METHODS AND RESULTS: We updated a systematic review of 9 GLP-1RA and 13 SGLT2i trials and summarized longitudinal mediator data. We obtained hazard ratios (HRs) for cardiovascular, renal, and mortality outcomes. We performed linear mixed-effects modeling of LogHRs versus changes in potential mediators and investigated differences in meta-regression associations among drug classes using interaction terms. HRs generally became more protective with greater glycated hemoglobin reduction among GLP-1RA trials, with average HR improvements of 20% to 30%, reaching statistical significance for major adverse cardiovascular events (ΔHR, 23%; P=0.02). Among SGLT2i trials, associations with HRs were not significant and differed from GLP1-RA trials for major adverse cardiovascular events (Pinteraction=0.04). HRs for major adverse cardiovascular events, myocardial infarction, and stroke became less efficacious (ΔHR, -15% to -34%), with more weight loss for SGLT2i but not for GLP-1RA trials (ΔHR, 4%-7%; Pinteraction<0.05). Among 5 SGLT2i trials with available data, HRs for stroke became less efficacious with larger increases in hematocrit (ΔHR, 123%; P=0.09). No changes in HRs by systolic blood pressure (ΔHR, -11% to 9%) and urine albumin-creatinine ratio (ΔHR, -1% to 4%) were found for any outcome. CONCLUSIONS: We confirmed increased efficacy findings for major adverse cardiovascular events with reduction in glycated hemoglobin for GLP1-RAs. Further research is needed on the potential loss of cardiovascular benefits with increased weight loss and hematocrit for SGLT2i.

41-Year-Old Male with Sub-Acute Encephalopathy, Seizures, and End Stage Renal Disease: A Unifying Diagnosis and Response to Therapy.

We describe a case of a 41-year-old male with a history of end-stage renal disease, hypertension, epilepsy, ischemic stroke, and traumatic brain injury transferred to our tertiary care center for subacute, progressive cognitive impairment. He was found to have disproportionate brain atrophy, focal seizures, and refractory hypertension. Given suspicion for an underlying genetic etiology, a genetic panel for progressive renal disease was sent, revealing two known pathogenic variants in a gene for a cobalamin metabolism disorder, Cobalamin C deficiency. He was started on targeted metabolic supplementation with subsequent improvement in his cognition. Our case highlights the crucial need to expand diagnostic workup to include genetic and metabolic causes in patients with neurologic disease, atypical features, relevant family history and multi-organ dysfunction.

ADPKD-Causing Missense Variants in Polycystin-1 Disrupt Cell Surface Localization or Polycystin Channel Function.

Autosomal dominant polycystic kidney disease (ADPKD) is the leading monogenic cause of kidney failure and affects millions of people worldwide. Despite the prevalence of this monogenic disorder, our limited mechanistic understanding of ADPKD has hindered therapeutic development. Here, we successfully developed bioassays that functionally classify missense variants in polycystin-1 (PC1). Strikingly, ADPKD pathogenic missense variants cluster into two major categories: 1) those that disrupt polycystin cell surface localization or 2) those that attenuate polycystin ion channel activity. We found that polycystin channels with defective surface localization could be rescued with a small molecule. We propose that small-molecule-based strategies to improve polycystin cell surface localization and channel function will be effective therapies for ADPKD patients.

Barriers and facilitators to the transplant process among patients living with polycystic kidney disease: a qualitative Approach.

BACKGROUND: Kidney transplant is the gold standard for renal replacement therapy in patients with autosomal dominant polycystic kidney disease (ADPKD), which is the fourth leading cause of kidney failure. Despite the medical and economic benefits of preemptive kidney transplant over dialysis before transplant, only 9-21% of qualifying patients receive preemptive transplants. Given the low rates of preemptive transplant, the aim of this study was to determine perceived facilitators and barriers to preemptive transplant among ADPKD patients using a qualitative approach. METHODS: Data were collected between July 2021 and January 2022 from virtual individual semi-structured interviews of 16 adult participants with ADPKD. Qualitative analysis of the recorded interviews was conducted to generate themes. RESULTS: Our findings revealed two themes specific for facilitators to preemptive transplant (social support and patient agency) and three themes specific to barriers for preemptive transplant (inadequate social support, gaps in knowledge, and institutional and systemic policies). The results also include various subthemes and the application of these themes to the social ecological model. CONCLUSIONS: These findings suggest that increasing social support and patient agency, such as through patient navigator programs and encouraging effective communication between health care providers and patients, can facilitate the transplant process. Increasing dissemination of transplant knowledge from institutions and systems to patients through paired kidney exchange education and live donor outreach can also increase timely access to preemptive kidney transplants for patients with ADPKD. Our findings are limited by our single site study in the US, which may not apply to individuals experiencing different social, cultural, and health access conditions.

Cardiovascular and Renal Benefits of Novel Diabetes Drugs by Baseline Cardiovascular Risk: A Systematic Review, Meta-analysis, and Meta-regression.

BACKGROUND: Eligibility for glucagon-like peptide 1 receptor agonists (GLP-1RA) and sodium-glucose cotransporter 2 inhibitors (SGLT2i) has been expanded to patients with diabetes at lower cardiovascular risk, but whether treatment benefits differ by risk levels is not clear. PURPOSE: To investigate whether patients with varying risks differ in cardiovascular and renal benefits from GLP-1RA and SGLT2i with use of meta-analysis and meta-regression. DATA SOURCES: We performed a systematic review using PubMed through 7 November 2022. STUDY SELECTION: We included reports of GLP-1RA and SGLT2i confirmatory randomized trials in adult patients with safety or efficacy end point data. DATA EXTRACTION: Hazard ratio (HR) and event rate data were extracted for mortality, cardiovascular, and renal outcomes. DATA SYNTHESIS: We analyzed 9 GLP-1RA and 13 SGLT2i trials comprising 154,649 patients. Summary HRs were significant for cardiovascular mortality (GLP-1RA 0.87 and SGLT2i 0.86), major adverse cardiovascular events (0.87 and 0.88), heart failure (0.89 and 0.70), and renal (0.84 and 0.65) outcomes. For stroke, efficacy was significant for GLP-1RA (0.84) but not for SGLT2i (0.92). Associations between control arm cardiovascular mortality rates and HRs were nonsignificant. Five-year absolute risk reductions (0.80-4.25%) increased to 11.6% for heart failure in SGLT2i trials in patients with high risk (Pslope < 0.001). For GLP1-RAs, associations were nonsignificant. LIMITATIONS: Analyses were limited by lack of patient-level data, consistency in end point definitions, and variation in cardiovascular mortality rates for GLP-1RA trials. CONCLUSIONS: Relative effects of novel diabetes drugs are preserved across baseline cardiovascular risk, whereas absolute benefits increase at higher risks, particularly regarding heart failure. Our findings suggest a need for baseline risk assessment tools to identify variation in absolute treatment benefits and improve decision-making.

Pharmacologic Management of Autosomal Dominant Polycystic Kidney Disease.

Autosomal dominant polycystic kidney disease (ADPKD) is the most common genetic kidney disorder and the fourth leading cause of end-stage kidney disease. ADPKD encompasses a wide range of morbidity in addition to chronic kidney disease and end-stage kidney disease, and its pathogenesis remains incompletely understood. Progress in the management of this condition includes the 2018 FDA approval of tolvaptan as the only mechanism-specific treatment available for individuals at risk of rapid progression. Assessing the risk of rapid progression is discussed at greater length in a separate article in this special issue. This section will address use and prescription of tolvaptan in more detail and address other therapies that may be considered in the treatment of patients with ADPKD.

Post-transplant ejection fraction and renal failure in cardiac transplant recipients: An analysis of the OPTN database.

BACKGROUND: Despite improved life expectancy from a heart transplant, transplant recipients remain at high risk for renal dysfunction and failure, including end-stage kidney disease (ESKD). The onset of ESKD is a poor prognostic marker and is associated with increased mortality in this setting, as in others. There is a need to identify risk factors for ESKD among heart transplant recipients in contemporary settings. METHODS: We conducted an analysis of adult heart transplant recipients transplanted between 2008 and 2021 in the Organ Procurement and Transplantation Network database. 22 737 adult recipients of heart transplants alone were included in this analysis. We examined LVEF measured 1 year after transplant, and LVEF updated annually for association with ESKD using multivariate Cox regression models. RESULTS: LVEF at 1-year after transplant was associated with ESKD in multivariate models (Hazard Ratio 1.33 per 10-unit decrease, 95% CI 1.23-1.43, p < .001). In multivariate models using categorized LVEF, mildly reduced ejection fraction (EF 40%-50%) was associated with ESKD (HR 1.76, 95% CI 1.45-2.14, p < .001), as was reduced ejection fraction (EF < 40%, HR 2.86, 95% CI 2.01-4.07, p < .001), relative to individuals with preserved ejection fraction (EF > 50%). These associations were consistent when using annually updated ejection fraction. CONCLUSIONS: Post-transplant left ventricular ejection fraction has value in predicting end stage kidney disease among adults who receive heart transplants alone. LVEF is routinely measured as part of contemporary post heart transplant care, and a diminished LVEF should signal to clinicians that a recipient is at increased risk of renal failure.

Design and Basic Characteristics of a National Patient-Powered Registry in ADPKD.

Background: Autosomal dominant polycystic kidney disease (ADPKD) is the most common form of inherited kidney disease worldwide. Over the past five years, the therapeutic pipeline for ADPKD has expanded, leading to a growing need for patient enrollment in clinical trials and improved understanding of patient-centered outcomes that can be used in trial design. To advance these goals, the Polycystic Kidney Disease Foundation (PKDF) established a national web-based ADPKD Registry. Methods: The ADPKD Registry is hosted on a secure, HIPAA-compliant, online platform (IQVIA, oc-meridian.com/pkdcure). Participants are consented through the online system and complete a series of modules. The Core Questionnaire includes patient-reported diagnosis, latest creatinine values, and comorbidities. Additional modules include surveys of family history, diet, quality of life, extrarenal manifestations, and attitudes surrounding research participation. Results: As of October 2021, 1563 ADPKD patients across the United States have registered and completed the Core Questionnaire. Participants have a median age of 44 years and are 72% women, 93% White, with 4% self-identifying as Hispanic/Latino and 2% as Black. All CKD stages are present, including post kidney transplant. To date, seven clinical studies have used the Registry as a recruitment tool. Additionally, quality-of-life burden scores revealed a correlation with disease stage as determined by kidney function. Conclusions: The Registry described here is the only one of its kind and is a valuable longitudinal research tool encompassing all stages of ADPKD. The registry will allow investigators to pursue a range of research questions related to the management of ADPKD, including definition of health-related quality of life (HRQoL) outcomes and recruitment for a variety of observational and therapeutic clinical protocols.

Pretransplant Dialysis and Preemptive Transplant in Living Donor Kidney Recipients.

Background: The optimal timing of dialysis access placement in individuals with stage 5 CKD is challenging to estimate. Preemptive living donor kidney transplant (LDKT) is the gold-standard treatment for ESKD due to superior graft survival and mortality, but dialysis initiation is often required. Among LDKT recipients, we sought to determine which clinical characteristics were associated with preemptive transplant. Among non-preemptive LDKT recipients, we sought to determine what dialysis access was used, and their duration of use before receipt of living donor transplant. Methods: We retrospectively extracted data on 569 LDKT recipients, >18 years old, who were transplanted between January 2014 and July 2019 at UCSF, including dialysis access type (arteriovenous fistula [AVF], arteriovenous graft [AVG], peritoneal dialysis catheter [PD], and venous catheter), duration of dialysis, and clinical characteristics. Results: Preemptive LDKT recipients constituted 30% of our cohort and were older, more likely to be White, more likely to have ESKD from polycystic kidney disease, and less likely to have ESKD from type 2 diabetes. Of the non-preemptive patients, 26% used AVF, 0.5% used AVG, 32% used peritoneal catheter, 11% used venous catheter, and 31% used more than one access type. Median (IQR) time on dialysis for AVF/AVG use was 1.86 (0.85-3.32) years; for PD catheters, 1.12 (0.55-1.92) years; for venous catheters, 0.66 (0.23-1.69) years; and for multimodal access, 2.15 (1.37-3.72) years. Conclusions: We characterized the dialysis access landscape in LDKT recipients. Venous catheter and PD were the most popular modality in the first quartile of dialysis, and patients using these modalities had shorter times on dialysis compared with those with an AVF. Venous catheter or PD can be considered a viable bridge therapy in patients with living donor availability given their shorter waitlist times. Earlier referral of patients with living donor prospects might further minimize dialysis need.

The effect of kidney transplantation on left ventricular remodeling and global diastolic strain rate in end-stage renal disease.

BACKGROUND: Diastolic dysfunction is an early marker of cardiac pathology in end-stage kidney disease (ESKD) patients. The ratio of transmitral filling velocity (E) to early diastolic strain rate (E/e'sr) is a novel non-invasive marker of early left ventricular (LV) filling pressure obtained using two-dimensional speckle tracking echocardiography (2DSTE). METHODS: In a prospective cohort of kidney transplant (KTX) recipients with echocardiograms performed pre-transplant we obtained repeat echocardiograms at 6 months following transplant. All echocardiograms were analyzed using 2DSTE where E/e'sr and global longitudinal strain were obtained. Paired tests were used to assess changes to cardiac structure and function following KTX. RESULTS: A total of 33 patients were included in the study (mean age was 46.6 ± 13.7 years and 42% were males). The primary causes of ESKD in the cohort were glomerular disease (33%), hypertension (30%), and polycystic kidney disease (12%). The median (IQR) time spent on dialysis was 5.4 years [2.9, 7.7 years]. A reverse remodeling of the LV was observed following KTX as LV mass decreased (189.2 ± 57.5 g vs 171.1 ± 56.8 g, P = 0.014). LV filling pressure decreased as assessed by E/e'sr (103.7 ± 51.1 cm vs 72.6 ± 35.5 cm, P = 0.009). E to early diastolic mitral annular tissue velocity (E/e') did not change following KTX (9.9 ± 4.5 vs 10.3 ± 4.1, P = 0.54). Additionally, both LV internal diastolic and systolic diameter decreased significantly. CONCLUSION: Reverse cardiac remodeling following KTX was observed as improvements in LV mass and LV dimensions. LV filling pressure improved as assessed by E/e'sr decreased following KTX, whereas E/e' did not change.

Post-Transplant Cardiovascular Disease.

Cardiovascular disease remains a leading cause of death and morbidity in kidney transplant recipients and a common reason for post-transplant hospitalization. Several traditional and nontraditional cardiovascular risk factors exist, and many of them present pretransplant and worsened, in part, due to the addition of immunosuppression post-transplant. We discuss optimal strategies for identification and treatment of these risk factors, including the emerging role of sodium-glucose cotransporter 2 inhibitors in post-transplant diabetes and cardiovascular disease. We present common types of cardiovascular disease observed after kidney transplant, including coronary artery disease, heart failure, pulmonary hypertension, arrhythmia, and valvular disease. We also discuss screening, treatment, and prevention of post-transplant cardiac disease. We highlight areas of future research, including the need for goals and best medications for risk factors, the role of biomarkers, and the role of screening and intervention.

Molecular Insights in Transmission of Cancer From an Organ Donor to Four Transplant Recipients.

Organ donors are systematically screened for infection, whereas screening for malignancy is less rigorous. The true incidence of donor-transmitted malignancies is unknown due to a lack of universal tumor testing in the posttransplant setting. Donor-transmitted malignancy may occur even when not suspected based on donor or recipient factors, including age and time to cancer diagnosis. We describe the detection of a gastrointestinal adenocarcinoma transmitted from a young donor to 4 transplant recipients. Multidimensional histopathologic and genomic profiling showed a CDH1 mutation and MET amplification, consistent with gastric origin. At the time of writing, one patient in this series remains alive and without evidence of cancer after prompt organ explant after cancer was reported in other recipients. Because identification of a donor-derived malignancy changes management, our recommendation is to routinely perform short tandem repeat testing (or a comparable assay) immediately upon diagnosis of cancer in any organ transplant recipient. Routine testing for a donor-origin cancer and centralized reporting of outcomes are necessary to establish a robust evidence base for the future development of clinical practice guidelines.

Prescription patterns of opioids and non-steroidal anti-inflammatory drugs in the first year after living kidney donation: An analysis of U.S. Registry and Pharmacy fill records.

We examined a novel database linking national donor registry identifiers to records from a US pharmaceutical claims warehouse (2007-2015) to describe opioid and NSAID prescription patterns among LKDs during the first year postdonation, divided into three periods: 0-14 days, 15-182 days, and 183-365 days. Associations of opioid and NSAID prescription fills with baseline factors were examined by logistic regression (adjusted odds ratio, LCL aORUCL ). Among 23,565 donors, opioid prescriptions were highest during days 0-14 (36.6%), but 12.6% of donors filled opioids during days 183-365. NSAID prescriptions rose from 0.5% during days 0-14 to 3.3% during days 183-365. Women filled opioids more commonly than men, and black donors filled both opioids and NSAIDs more commonly than white donors. After covariate adjustment, significant correlates of opioid prescription fills during days 183-365 included obesity (aOR,1.24 1.381.53 ), less than college education (aOR,1.19 1.311.43 ), smoking (aOR,1.33 1.451.58 ), and nephrectomy complications (aOR,1.11 1.291.49 ). NSAID prescription fills in year 1 were not associated with differences in estimated glomerular filtration rate, incidence of proteinuria or new-onset hypertension at the first and second year postdonation. Prescription fills for opioids and NSAIDs for LKDs varied with demographic and clinic traits. Future work should examine longer-term outcome implications to help inform safe analgesic regimen choices after donation.

APOL1 Long-term Kidney Transplantation Outcomes Network (APOLLO): Design and Rationale.

INTRODUCTION: Much of the higher risk for end-stage kidney disease (ESKD) in African American individuals relates to ancestry-specific variation in the apolipoprotein L1 gene (APOL1). Relative to kidneys from European American deceased-donors, kidneys from African American deceased-donors have shorter allograft survival and African American living-kidney donors more often develop ESKD. The National Institutes of Health (NIH)-sponsored APOL1 Long-term Kidney Transplantation Outcomes Network (APOLLO) is prospectively assessing kidney allograft survival from donors with recent African ancestry based on donor and recipient APOL1 genotypes. METHODS: APOLLO will evaluate outcomes from 2614 deceased kidney donor-recipient pairs, as well as additional living-kidney donor-recipient pairs and unpaired deceased-donor kidneys. RESULTS: The United Network for Organ Sharing (UNOS), Association of Organ Procurement Organizations, American Society of Transplantation, American Society for Histocompatibility and Immunogenetics, and nearly all U.S. kidney transplant programs, organ procurement organizations (OPOs), and histocompatibility laboratories are participating in this observational study. APOLLO employs a central institutional review board (cIRB) and maintains voluntary partnerships with OPOs and histocompatibility laboratories. A Community Advisory Council composed of African American individuals with a personal or family history of kidney disease has advised the NIH Project Office and Steering Committee since inception. UNOS is providing data for outcome analyses. CONCLUSION: This article describes unique aspects of the protocol, design, and performance of APOLLO. Results will guide use of APOL1 genotypic data to improve the assessment of quality in deceased-donor kidneys and could increase numbers of transplanted kidneys, reduce rates of discard, and improve the safety of living-kidney donation.

Postdonation eGFR and New-Onset Antihypertensive Medication Use After Living Kidney Donation.

BACKGROUND: Limited data are available regarding clinical implications of lower renal function after living kidney donation. We examined a novel integrated database to study associations between postdonation estimated glomerular filtration rate (eGFR) and use of antihypertensive medication (AHM) treatment after living kidney donation. METHODS: Study data were assembled by linking national U.S. transplant registry identifiers, serum creatinine (SCr) values from electronic medical records, and pharmacy fill records for 3222 living donors (1989-2016) without predonation hypertension. Estimated GFR (mL/min per 1.73 m2) was computed from SCr values by the CKD-EPI equation. Repeated measures multivariable mixed effects modeling examined the associations (adjusted odds ratio, 95%LCLaOR95% UCL) between AHM use and postdonation eGFR levels (random effect) with fixed effects for baseline donor factors. RESULTS: The linked database identified an average of 3 postdonation SCr values per donor (range: 1-38). Lower postdonation eGFR (vs ≥75) bore graded associations with higher odds of AHM use (eGFR 30-44: aOR 0.951.472.26; <30: aOR 1.082.525.90). Other independent correlates of postdonation AHM use included older age at donation (aOR per decade: 1.081.231.40), black race (aOR 1.031.512.21), body mass index > 30 kg/m2 (aOR 1.011.452.09), first-degree donor-recipient relationship (aOR 1.071.381.79), "prehypertension" at donation (systolic blood pressure 120-139: aOR 1.101.461.94; diastolic blood pressure 80-89: aOR 1.061.451.99). CONCLUSIONS: This novel linkage illustrates the ability to identify postdonation kidney function and associate it with clinically meaningful outcomes; lower eGFR after living kidney donation is a correlate of AHM treatment requirements. Further work should define relationships of postdonation renal function, hypertension, and other morbidity measures.

Development and Validation of a Pragmatic Electronic Phenotype for CKD.

BACKGROUND AND OBJECTIVES: Poor identification of individuals with CKD is a major barrier to research and appropriate clinical management of the disease. We aimed to develop and validate a pragmatic electronic (e-) phenotype to identify patients likely to have CKD. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: The e-phenotype was developed by an expert working group and implemented among adults receiving in- or outpatient care at five healthcare organizations. To determine urine albumin (UA) dipstick cutoffs for CKD to enable use in the e-phenotype when lacking urine albumin-to-creatinine ratio (UACR), we compared same day UACR and UA results at four sites. A sample of patients, spanning no CKD to ESKD, was randomly selected at four sites for validation via blinded chart review. RESULTS: The CKD e-phenotype was defined as most recent eGFR <60 ml/min per 1.73 m2 with at least one value <60 ml/min per 1.73 m2 >90 days prior and/or a UACR of ≥30 mg/g in the most recent test with at least one positive value >90 days prior. Dialysis and transplant were identified using diagnosis codes. In absence of UACR, a sensitive CKD definition would consider negative UA results as normal to mildly increased (KDIGO A1), trace to 1+ as moderately increased (KDIGO A2), and ≥2+ as severely increased (KDIGO A3). Sensitivity, specificity, and diagnostic accuracy of the CKD e-phenotype were 99%, 99%, and 98%, respectively. For dialysis sensitivity was 94% and specificity was 89%. For transplant, sensitivity was 97% and specificity was 91%. CONCLUSIONS: The CKD e-phenotype provides a pragmatic and accurate method for EHR-based identification of patients likely to have CKD.