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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., Graphical abstract

Background Patients with autosomal dominant polycystic kidney disease (ADPKD) have an increased risk of cardiovascular morbidity and mortality. Impaired left ventricular (LV) global longitudinal strain (GLS) can be a sign of subclinical cardiac dysfunction even in patients with otherwise preserved ejection fraction (EF). Transmitral early filling velocity to early diastolic strain rate (E/SRe) is a novel measure of LV filling pressure, which is often affected early in cardiac disease. Methods A total of 110 ADPKD patients not on dialysis were included in this prospective study. All patients underwent an extensive echocardiographic examination including two-dimensional speckle tracking. GLS and strain rates were measured. The distribution of GLS and E/SRe was determined and patient characteristics were compared by median levels of GLS (− 17.8%) and E/SRe (91.4 cm). Twenty healthy participants were included as control group. Results There was a significantly worse GLS in the ADPKD patients (mean: − 17.8 ± 2.5%) compared to the healthy controls (mean: − 21.9 ± 1.9%), p

The omission of outcomes that are of relevance to patients, clinicians, and regulators across trials in autosomal dominant polycystic kidney disease (ADPKD) limits shared decision making. The Standardized Outcomes in Nephrology-Polycystic Kidney Disease (SONG-PKD) Initiative convened an international consensus workshop on October 25, 2018, to discuss the identification and implementation of a potential core outcome set for all ADPKD trials. This article summarizes the discussion from the workshops and the SONG-PKD core outcome set. Key stakeholders including 11 patients/ caregivers and 47 health professionals (nephrologists, policy makers, industry, and researchers) attended the workshop. Four themes emerged: "Relevance of trajectory and impact of kidney function" included concerns about a patient's prognosis and uncertainty of when they may need to commence kidney replacement therapy and the lack of an early prognostic marker to inform long-term decisions; "Discerning and defining pain specific to ADPKD" highlighted the challenges in determining the origin of pain, adapting to the chronicity and repeated episodes of pain, the need to place emphasis on pain management, and to have a validated measure for pain; "Highlighting ADPKD consequences" encompassed cyst-related complications and reflected patient's knowledge because of family history and the hereditary nature of ADPKD; and "Risk for life-threatening but rare consequences" such as cerebral aneurysm meant considering both frequency and severity of the outcome. Kidney function, mortality, cardiovascular disease, and pain were established as the core outcomes for ADPKD.

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 aCDH1mutation andMETamplification, 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.

A 10-plex urine-based bladder cancer (BCa) diagnostic signature has the potential to non-invasively predict the presence of BCa in at-risk patients, as reported in various case-control studies. The present meta-analysis was performed to re-evaluate and demonstrate the robustness and consistency of the diagnostic utility of the 10-plex urine-based diagnostic assay. We re-analyzed primary data collected in five previously published case-control studies on the 10-plex diagnostic assay. Studies reported the sensitivity and specificity of ten urinary protein biomarkers for the detection of BCa, including interleukin 8, matrix metalloproteinases 9 and 10, angiogenin, apolipoprotein E, syndecan 1, alpha-1 antitrypsin, plasminogen activator inhibitor-1, carbonic anhydrase 9, and vascular endothelial growth factor A. Data were extracted and reviewed independently by two investigators. Log odds ratios (ORs) were calculated to determine how strongly the 10-plex biomarker panel and individual biomarkers are associated with the presence of BCa. Data pooled from 1,173 patients were analyzed. The log OR for each biomarker was improved by 1.5 or greater with smaller 95% CI in our meta-analysis of the overall cohort compared with each analysis of an individual cohort. The combination of the ten biomarkers showed a higher log OR (log OR: 3.46, 95% CI: 2.60-4.31) than did any single biomarker irrespective of histological grade or disease stage of tumors. We concluded that the 10-plex BCa-associated diagnostic signature demonstrated a higher potential to identify BCa when compared to any single biomarker. Our results justify further advancement of the 10-plex protein-based diagnostic signature toward clinical application.

Background and aimsTumor necrosis factor receptor type 1 (TNFR1) is associated with kidney disease and mortality risk in various populations. Whether or not kidney function mediates mortality risk is unknown. We evaluated associations of TNFR1 levels with measures of kidney function, cardiovascular events, and mortality in a population of veterans with stable ischemic heart disease.MethodsTNFR1 was measured from baseline serum samples in the Heart and Soul Study; elevated levels were defined by the highest quartile (Q4, >3.4ng/ml). We evaluated associations of high TNFR1 with baseline estimated glomerular filtration rate (eGFR) and urine albumin to creatinine ratio (ACR) and with longitudinal changes in eGFR (rapid loss), as well as with incident myocardial infarction (MI), heart failure hospitalizations (HF), and mortality over a median follow-up time of 8.9 years. Covariates included demographics and comorbid conditions.ResultsAmong 985 participants who had TNFR1 measurements, median TNFR1 was 2.33ng/ml (IQR 1.8-3.1). Relative to Q1, Q4 had higher risk of eGFR

Background and objectives CKD is an important risk factor for cardiovascular disease (CVD) and death. We investigated whether select urine kidney injury biomarkers were associated with higher risk of heart failure (HF), CVD, and death in persons with CKD enrolled in the Chronic Renal Insufficiency Cohort (CRIC) Study. Design, setting, participants, & measurements Urine kidney injury molecule-1 (KIM-1), neutrophil gelatinase-associated lipocalin, liver fatty acid-binding protein, and N -acetyl -β- d-glucosaminidase were measured in urine of a subset of CRIC participants ( n =2466). We used Cox proportional hazards regression to examine associations between these biomarkers indexed to urinary creatinine (Cr) and ( 1 ) HF, ( 2 ) a composite of atherosclerotic CVD events (myocardial infarction, ischemic stroke, or peripheral artery disease), and ( 3 ) all-cause death. Results At baseline, mean age of study participants was 59.5±10.8 years, 46% were women, and 34% had a self-reported history of any CVD. Median follow-up was 6.5 (interquartile range, 5.6–6.8) years. A total of 333 HF events, 282 atherosclerotic CVD events, and 440 deaths were observed during a median follow-up of 6.5 (interquartile range, 5.6–6.8) years. Those in the highest two quintiles of KIM-1/Cr levels had a higher risk of HF relative to the lowest quintile (quintile 5 versus quintile 1 adjusted hazard ratio [aHR] of 1.73 [95% confidence interval, 1.05 to 2.85]). N -acetyl -β- d-glucosaminidase/Cr was associated with HF in continuous analyses (aHR per log SD higher 1.18 [95% confidence interval, 1.01 to 1.38]). Only KIM-1/Cr was independently associated with atherosclerotic CVD events (aHR per log SD higher 1.21 [95% confidence interval, 1.02 to 1.41]), whereas both KIM-1/Cr (quintile 5 versus quintile 1 aHR of 1.56 [95% confidence interval, 1.06 to 2.31]) and neutrophil gelatinase-associated lipocalin/Cr (quintile 5 versus quintile 1 aHR of 1.82 [95% confidence interval, 1.19 to 2.8]) were associated with all-cause death. Conclusions Selected urine kidney injury biomarkers were independently associated with higher risk of HF, CVD events, and death in CRIC. Among the biomarkers examined, only KIM-1/Cr was associated with each outcome. Further work is needed to determine the utility of these biomarkers to improve risk prediction for these adverse outcomes.

Author(s): Lentine, Krista L; Holscher, Courtenay M; Naik, Abhijit S; Lam, Ngan N; Segev, Dorry L; Garg, Amit X; Axelrod, David; Xiao, Huiling; Henderson, Macey L; Massie, Allan B; Kasiske, Bertram L; Hess, Gregory P; Hsu, Chi-Yuan; Park, Meyeon; Schnitzler, Mark A | Abstract: BackgroundLimited 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.MethodsStudy 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.ResultsThe 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; l30: 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 g 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).ConclusionsThis 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.

Lupus nephritis is a potentially fatal autoimmune disease for which the current treatment is ineffective and often toxic. To develop mechanistic hypotheses of disease, we analyzed kidney samples from patients with lupus nephritis and from healthy control subjects using single-cell RNA sequencing. Our analysis revealed 21 subsets of leukocytes active in disease, including multiple populations of myeloid cells, T cells, natural killer cells and B cells that demonstrated both pro-inflammatory responses and inflammation-resolving responses. We found evidence of local activation of B cells correlated with an age-associated B-cell signature and evidence of progressive stages of monocyte differentiation within the kidney. A clear interferon response was observed in most cells. Two chemokine receptors, CXCR4 and CX3CR1, were broadly expressed, implying a potentially central role in cell trafficking. Gene expression of immune cells in urine and kidney was highly correlated, which would suggest that urine might serve as a surrogate for kidney biopsies.

Autosomal dominant polycystic kidney disease (ADPKD) is the most prevalent genetic kidney disease. It carries high lifetime morbidity not only due to chronic kidney disease, but also due to a higher risk of cardiovascular death. Multiple metabolic abnormalities associated with ADPKD including insulin resistance and hyperlipidemia as well as subclinical cardiovascular abnormalities, such as left ventricular hypertrophy (LVH), contribute to this cardiovascular risk. These conditions may manifest before evidence of worsening estimated glomerular filtration rate (eGFR). Renal oxidative stress also occurs early in the disease and is a driver of ADPKD progression. Animal models have shown that calorie restriction may mitigate these inflammatory processes. Further research is required to show whether attenuation of metabolic abnormalities associated with ADPKD may improve renal and cardiovascular morbidity. .

Lupus nephritis is a potentially fatal autoimmune disease, whose current treatment is ineffective and often toxic. To gain insights into disease mechanisms, we analyzed kidney samples from lupus nephritis patients and healthy controls using single-cell RNA-seq. Our analysis revealed 21 subsets of leukocytes active in disease, including multiple populations of myeloid, T, NK and B cells, demonstrating both pro-inflammatory and resolving responses. We found evidence of local activation of B cells correlated with an age-associated B cell signature, and of progressive stages of monocyte differentiation within the kidney. A clear interferon response was observed in most cells. Two chemokine receptors, CXCR4 and CX3CR1, were broadly expressed, pointing to potential therapeutic targets. Gene expression of immune cells in urine and kidney was highly correlated, suggesting urine may be a surrogate for kidney biopsies. Our results provide a first comprehensive view of the complex network of leukocytes active in lupus nephritis kidneys.

Recipients of kidney transplants (KTR) are at increased risk for cardiovascular events, graft failure, and death. It is unknown whether urine kidney injury biomarkers are associated with poor outcomes among KTRs. We conducted a post hoc analysis of the Folic Acid for Vascular Outcome Reduction in Transplantation (FAVORIT) Trial using a case-cohort study design, selecting participants with adjudicated cardiovascular events, graft failure, or death. Urine neutrophil gelatinase–associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), IL-18, and liver–type fatty acid binding protein (L-FABP) were measured in spot urine samples and standardized to urine creatinine concentration. We adjusted for demographics, cardiovascular risk factors, eGFR, and urine albumin-to-creatinine ratio. Patients had 291 cardiovascular events, 257 graft failure events, and 359 deaths. Each log increase in urine NGAL/creatinine independently associated with a 24% greater risk of cardiovascular events (adjusted hazard ratio [aHR], 1.24; 95% confidence interval [95% CI], 1.06 to 1.45), a 40% greater risk of graft failure (aHR, 1.40; 95% CI, 1.16 to 1.68), and a 44% greater risk of death (aHR, 1.44; 95% CI, 1.26 to 1.65). Urine KIM-1/creatinine and IL-18/creatinine independently associated with greater risk of death (aHR, 1.29; 95% CI, 1.03 to 1.61 and aHR, 1.25; 95% CI, 1.04 to 1.49 per log increase, respectively) but not with risk of cardiovascular events or graft failure. Urine L-FABP did not associate with any study outcomes. In conclusion, among prevalent KTRs, higher urine NGAL, KIM-1, and IL-18 levels independently and differentially associated with greater risk of adverse outcomes.

Author(s): Shlipak, Michael; Hsu, Chi-Yuan; Park, M; Shlipak, MG; Vittinghoff, E; Katz, R; Siscovick, D; Sarnak, M; Lima, JA; Hsu, CY; Peralta, CA

Acute kidney injury (AKI) is a critical determinant of outcomes in hospitalized patients with cirrhosis, but little is known of the impact of AKI in the outpatient setting. We analyzed 385 adult outpatients with cirrhosis listed for liver transplant at a single center; excluded were those with severe hepatic encephalopathy, with hepatocellular carcinoma, or on hemodialysis. Baseline serum creatinine (bCr) was defined as the lowest value recorded, peak Cr as the highest value, ΔCr as peak Cr minus bCr, AKI as a rise in serum Cr (sCr) by ≥0.3 mg/dL from bCr, persistent kidney injury as elevation of sCR by ≥0.3 mg/dL from bCr on each subsequent clinical assessment. Among 385 outpatients with cirrhosis, bCr was ≤0.70, 0.70-0.97, and ≥0.97 mg/dL in 28%, 38%, and 34%, respectively. At a median follow-up of 16 (range 8-28) months, 143 (37%) had one or more AKI episode, which increased significantly by bCr group (24% versus 37% versus 48%, P = 0.001). Of these 143 with AKI, 13% developed persistent kidney injury. A multivariable Cox regression analysis highlighted that bCr (hazard ratio [HR], 2.96) and ΔCr (HR, 2.05) were the only factors independently associated with the development of persistent kidney injury (P

Tumor necrosis factor receptor type 1 (TNFR1) is associated with kidney disease and mortality risk in various populations [1], [2]. We evaluated associations of TNFR1 with mortality and mediators of this relationship in doi: 10.1016/j.atherosclerosis.2017.05.021. Whether or not these associations are influenced by age, gender, or baseline kidney function are not known. We evaluated associations of TNFR1 levels with measures of kidney function stratifying by these variables. Our outcomes included estimated glomerular filtration rate (eGFR) < 60ml/min/1.73m2, albumin to creatinine ratio (ACR) >30mg/g, and rapid kidney function loss, defined as a change in eGFR of greater than 3% per year.

Background Autosomal dominant polycystic kidney disease (PKD) is the most common genetic renal disease and the fourth leading cause of end-stage renal disease in the United States. Although there is no cure for PKD, several treatments are considered to be beneficial, including blood pressure control, exercise, low-salt diet, and high volume water intake. However, levels of understanding of the importance of these treatments and adherence to these recommendations vary among patients. This study explores illness perception models of patients with PKD to reveal barriers in adherence to prescribed therapies; satisfaction with medical care; and sources of medical information. Methods We designed a phenomenological interview study to evaluate illness perception models of individuals with PKD. Patients were identified from the national PKD Foundation e-mail distribution list (N = 190) and responded voluntarily to an introductory survey (N = 50). Seventeen PKD patients in the Bay Area were scheduled for one-on-one in-depth interviews with one trained interviewer (W-CT). Open-ended questions administered with an interview guide were used to evaluate patients’ beliefs. Results Mean age was 56.6 +/− 12 years (range 29–78); 65% were female. Many of the PKD patients in this study were highly motivated and willing to incorporate blood pressure, exercise, low-salt diet, and high volume water intake into their daily routines. Barriers to adherence to these therapies include personal beliefs and confusion due to unclear recommendations. Conclusions These findings suggest there is variability between what patients understand about their disease and treatments and what they believe their doctors have told them. Not all physicians focus on lifestyle-based treatments, but the majority of PKD patients in our study are motivated and willing to incorporate blood pressure control, exercise, low-salt diet, and high volume water intake into their daily routines and would like specific recommendations on how to implement these. These findings support a role for further exploring patient beliefs about the disease and its necessary treatments in order to design strategies to improve communication and meet the needs of these patients. Electronic supplementary material The online version of this article (doi:10.1186/s12882-017-0641-3) contains supplementary material, which is available to authorized users.

The CACNA1H gene encodes the pore-forming α1 subunit of the T-type voltage-dependent calcium channel CaV3.2, expressed abundantly in the adrenal cortex. Mutations in CACNA1H are associated with various forms of primary aldosteronism (PA), including familial hyperaldosteronism type 4 (FH4). We describe a patient with refractory hypokalaemia and elevated aldosterone secretion independent of renin activity. Despite the absence of overt hypertension in this patient, the laboratory evaluation was consistent with a diagnosis of PA. Whole-exome sequencing revealed a de novo missense variant, R890H, in the voltage sensing domain of CACNA1H. Expression of the variant channel in cells resulted in decreased whole-cell current, consistent with a loss-of-function. We hypothesise this variant is the genetic cause of pathological aldosterone secretion in this patient, and thereby expand the current understanding of the genetic basis of FH4.

Cardiovascular risk remains high in kidney transplant recipients (KTRs) despite improved kidney function after transplant. Urinary markers of kidney fibrosis and injury may help to reveal mechanisms of this risk. In a case-cohort study among stable KTRs who participated in the FAVORIT trial, we measured four urinary proteins known to correlate with kidney tubulointerstitial fibrosis on biopsy (urine alpha 1 microglobulin [α1m], monocyte chemoattractant protein-1 [MCP-1], procollagen type I [PINP] and type III [PIIINP] N-terminal amino peptide) and evaluated associations with cardiovascular disease (CVD) events (n = 300) and death (n = 371). In adjusted models, higher urine α1m (hazard ratio [HR] per doubling of biomarker 1.40 [95% confidence interval [CI] 1.21, 1.62]), MCP-1 (HR 1.18 [1.03, 1.36]), and PINP (HR 1.13 [95% CI 1.03, 1.23]) were associated with CVD events. These three markers were also associated with death (HR per doubling α1m 1.51 [95% CI 1.32, 1.72]; MCP-1 1.31 [95% CI 1.13, 1.51]; PINP 1.11 [95% CI 1.03, 1.20]). Higher concentrations of urine α1m, MCP-1, and PINP may identify KTRs at higher risk for CVD events and death. These markers may identify a systemic process of fibrosis involving both the kidney and cardiovascular system, and give new insights into mechanisms linking the kidney with CVD.

Background Acute kidney injury is a risk factor for death in cardiac surgical patients. Plasma cystatin C and creatinine have different temporal profiles in the postoperative setting, but the associations of simultaneous changes in both filtration markers compared with change in only one marker with prognosis after hospital discharge are not well described. Methods This is a longitudinal study of 1,199 high-risk adult cardiac surgical patients in the TRIBE-AKI (Translational Research Investigating Biomarker Endpoints for Acute Kidney Injury) Consortium who survived hospitalization. We examined in-hospital peak changes of cystatin C and creatinine in the 3 days after cardiac operations. We evaluated associations of these filtration markers with death, adjusting for demographics, operative characteristics, medical comorbidities, preoperative estimated glomerular filtration rate, preoperative urinary albumin-to-creatinine ratio, and site. Results During the first 3 days of hospitalization, nearly twice as many patients had a 25% or higher rise in creatinine (30%) compared with a 25% or higher peak rise in cystatin C (15%). The risk of death was higher in those with elevations in cystatin C (adjusted hazard ratio [HR], 1.83; 95% confidence interval [CI], 1.4 to 2.37) or creatinine (adjusted HR, 1.90; 95% CI, 1.32 to 2.72) compared with patients who experienced a postoperative decrease in either filtration marker. Patients who had simultaneous elevations of 25% or higher in cystatin C and creatinine were at similar adjusted risk for 3-year mortality (HR, 1.79; 95% CI, 1.03 to 3.1) as those with a 25% or higher increase in cystatin C alone (HR, 2.2; 95% CI, 1.09 to 4.47). Conclusions Elevations in creatinine postoperatively are more common than elevations in cystatin C. However, elevations in cystatin C appeared to be associated with a higher risk of death after hospital discharge.

Individuals with acute heart failure exacerbation often experience a deterioration in renal function. We sought to determine whether this deterioration is ischemic in nature and detectable by sensitive urine biomarkers neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1). We measured serial biomarker levels and evaluated the associations of these biomarkers with renal recovery in a cohort of hospitalized patients with acute heart failure exacerbation.

Objective We have previously shown that peripheral artery disease (PAD) is associated with marked impairment of endothelial function (EF). Given that poor EF is associated with functional status of PAD patients as well as with increased morbidity and mortality in patients undergoing vascular procedures, determination of factors associated with poor EF in a PAD cohort is important. We hypothesized that decreased kidney function is associated with impaired EF in patients with PAD. Methods This was a cross-sectional study of PAD patients presenting to a vascular surgery outpatient clinic at the San Francisco Veterans Affairs Medical Center including patients enrolled in the OMEGA-PAD I trial (NCT01310270) and the OMEGA-PAD Cohort. Brachial artery flow-mediated vasodilation was performed to assess EF. Kidney function was characterized by estimated glomerular filtration rate with the abbreviated Modification of Diet in Renal Disease formula. Linear regression was performed to assess the relationship between EF and kidney function in claudicants. Results Ninety-seven patients with intermittent claudication participated in this study. Mean age was 69 ± 8 years, 97% were male, and 79% were white. Comorbidities included hypertension (91%), dyslipidemia (87%), coronary artery disease (42%), and diabetes mellitus (38%). Mean ankle-brachial index was 0.73 ± 0.14 and mean flow-mediated vasodilation was 7.0% ± 3.8%, indicating impaired EF. Linear regression showed an association between kidney function and EF (by 10 mL/min/1.73 m 2 ; β, 0.12; confidence interval, 0.05-0.20; P = .001). After multivariable regression adjusting for age, race, log tumor necrosis factor α, hypertension, dyslipidemia, and diabetes, estimated glomerular filtration rate remained significantly associated with EF ( P = .033). Conclusions In patients with PAD, decreased kidney function is associated with endothelial dysfunction. Further longitudinal studies are needed to better understand the impact of kidney function on PAD progression and the role of endothelial dysfunction in this process.