Publications by authors named "Robert N Foley"

155 Publications

Randomized Controlled Trials 4: Planning, Analysis, and Interpretation of Quality-of-Life Studies.

Methods Mol Biol 2021 ;2249:247-259

Clinical Epidemiology Unit, Faculty of Medicine, Memorial University, St. John's, NL, Canada.

Quality-of-life (QoL) outcomes are important elements of randomized controlled trials. The instruments for measurement of QoL vary but usually multiple comparisons are possible, a concern that can be offset by prespecifying the outcomes of interest. Missing data may threaten the validity of QoL assessments in trials. Therefore, familiarity with the strategies used to account for missing data is necessary. Measures that incorporate both survival and QoL are helpful for treatment decisions. The definition of minimal clinically important differences in QoL scores is important and often derived using inadequate methods.
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http://dx.doi.org/10.1007/978-1-0716-1138-8_14DOI Listing
June 2021

Randomized Controlled Trials 2: Analysis.

Methods Mol Biol 2021 ;2249:213-227

Clinical Epidemiology Unit, Department of Medicine, Faculty of Medicine, Memorial University, St. John, NL, Canada.

When analyzing the results of a trial, the primary outcome variable must be kept in clear focus. In the analysis plan, consideration must be given to comparing the characteristics of the subjects, taking account of differences in these characteristics, intention-to-treat analysis, interim analyses and stopping rules, mortality comparisons, composite outcomes, research design including run-in periods, factorial, stratified and crossover designs, number needed to treat, power issues, multivariate modeling, subgroup analysis, competing risks, and hypothesis-generating analyses.
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http://dx.doi.org/10.1007/978-1-0716-1138-8_12DOI Listing
June 2021

Treatment Strategies in CKD Patients With Suspected Coronary Artery Disease.

Authors:
Robert N Foley

Am J Kidney Dis 2019 10;74(4):438-440

Division of Renal Diseases and Hypertension, University of Minnesota, Minneapolis, MN. Electronic address:

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http://dx.doi.org/10.1053/j.ajkd.2019.06.004DOI Listing
October 2019

Time to thrombectomy is associated with increased risk for dialysis catheter placement.

J Ren Care 2019 Dec 26;45(4):232-238. Epub 2019 Aug 26.

Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA.

Background: Arteriovenous dialysis access, fistulae (AVF) or grafts (AVG), are associated with significant rates of thrombosis. Timely thrombectomy may have a significant impact on immediate and long-term access survival. However, switching to a catheter is associated with higher rates of morbidity and mortality compared with those who have an AVF or AVG.

Objectives: The goal of this study was to evaluate whether time to thrombectomy increases the risk for loss of dialysis access and subsequent placement of a dialysis catheter at hospital discharge, at 6 months, 12 months, and data at any time after discharge.

Methods: Using retrospective data, 444 patients were identified as having undergone thrombectomy for dialysis access dysfunction between January 2008 and April 2015, with 122 hospital admissions primarily for thrombectomy.

Results: The mean age was 60.4 years, 65% were male, and 44.3% had an arteriovenous fistula as their dialysis access. The mean time to thrombectomy was 10.8 hours, and 14 patients utilised a catheter for haemodialysis as primary access upon discharge. After adjustment for prior access intervention, access type, and time to thrombectomy, the adjusted odds ratios (AOR) of a one-day delay in thrombectomy was associated with a twofold increase in requirement for catheter at discharge and at 6 months. This association remained present at any time after discharge.

Conclusion: In this study of patients cared for within an academic health system, a single day delay in thrombectomy nearly doubled the risk of needing a dialysis catheter at hospital discharge, 6 months, or any time after discharge.
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http://dx.doi.org/10.1111/jorc.12295DOI Listing
December 2019

Trends in Angiotensin-Converting Enzyme Inhibitor and Angiotensin II Receptor Blocker Use among Those with Impaired Kidney Function in the United States.

J Am Soc Nephrol 2019 07 5;30(7):1314-1321. Epub 2019 Jun 5.

Department of Medicine, University of Minnesota, Minneapolis, Minnesota

Background: Although hypertension is common in CKD and evidence-based treatment of hypertension has changed considerably, contemporary and nationally representative information about use of angiotensin-converting enzyme (ACEs) inhibitors or angiotensin II receptor blockers (ARBs) in CKD is lacking.

Methods: We examined ACE/ARB trends from 1999 to 2014 among 38,885 adult National Health and Nutrition Examination Survey participants with creatinine-based eGFR<60 ml/min per 1.73 m or urinary albumin-to-creatinine ratio ≥30 mg/g.

Results: Of 7085 participants with CKD, 34.9% used an ACE/ARB. Across four eras studied, rates of use rose significantly (rates were 25.5% in 1999-2002, 33.3% in 2003-2006, 39.0% in 2007-2010, and 40.1% in 2011-2014) but appeared to plateau after 2003. Among those with CKD, use was significantly greater among non-Hispanic white and black individuals (36.1% and 38.2%, respectively) and lower among Hispanic individuals (26.7%) and other races/ethnicities (29.3%). In age-, sex-, and race/ethnicity-adjusted models, ACE/ARB use was significantly associated with era (adjusted odds ratios [aOR], 1.41; 95% confidence interval [95% CI], 1.14 to 1.74 for 2003-2006, 1.84; 95% CI, 1.48 to 2.28 for 2007-2010, and 2.02; 95% CI, 1.61 to 2.53 for 2011-2014 versus 1999-2002); it also was significantly associated with non-Hispanic black versus non-Hispanic white race/ethnicity (aOR, 1.40; 95% CI, 1.19 to 1.66). Other multivariate associations included older age, men, elevated BMI, diabetes mellitus, treated hypertension, cardiac failure, myocardial infarction, health insurance, and receiving medical care within the prior year.

Conclusions: Rates of ACE/ARB use increased in the early 2000s among United States adults with CKD, but for unclear reasons, use appeared to plateau in the ensuing decade. Research examining barriers to care and other factors is needed.
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http://dx.doi.org/10.1681/ASN.2018100971DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6622408PMC
July 2019

Race, Ethnicity, and End-of-Life Care in Dialysis Patients in the United States.

J Am Soc Nephrol 2018 09 9;29(9):2387-2399. Epub 2018 Aug 9.

Division of Medicine, Minneapolis Veterans Affairs Health Care System, Minneapolis, Minnesota.

Background: End-of-life care is a prominent consideration in patients on maintenance dialysis, especially when death appears imminent and quality of life is poor. To date, examination of race- and ethnicity-associated disparities in end-of-life care for patients with ESRD has largely been restricted to comparisons of white and black patients.

Methods: We performed a retrospective national study using United States Renal Data System files to determine whether end-of-life care in United States patients on dialysis is subject to racial or ethnic disparity. The primary outcome was a composite of discontinuation of dialysis and death in a nonhospital or hospice setting.

Results: Among 1,098,384 patients on dialysis dying between 2000 and 2014, the primary outcome was less likely in patients from any minority group compared with the non-Hispanic white population (10.9% versus 22.6%, <0.001, respectively). We also observed similar significant disparities between any minority group and non-Hispanic whites for dialysis discontinuation (16.7% versus 31.2%), as well as hospice (10.3% versus 18.1%) and nonhospital death (34.4% versus 46.4%). After extensive covariate adjustment, the primary outcome was less likely in the combined minority group than in the non-Hispanic white population (adjusted odds ratio, 0.55; 95% confidence interval, 0.55 to 0.56; <0.001). Individual minority groups (non-Hispanic Asian, non-Hispanic black, non-Hispanic Native American, and Hispanic) were significantly less likely than non-Hispanic whites to experience the primary outcome. This disparity was especially pronounced for non-Hispanic Native American and Hispanic subgroups.

Conclusions: There appear to be substantial race- and ethnicity-based disparities in end-of-life care practices for United States patients receiving dialysis.
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http://dx.doi.org/10.1681/ASN.2017121297DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6115657PMC
September 2018

Design of a clinical risk calculator for major clinical outcomes in patients with atherosclerotic renovascular disease.

Nephrol Dial Transplant 2019 08;34(8):1377-1384

Department of Renal Medicine, Salford Royal NHS Foundation Trust, Salford, Greater Manchester, UK.

Background: Risk stratification in atherosclerotic renovascular disease (ARVD) can influence treatment decisions and facilitate patient selection for revascularization. In this study, we aim to use variables with the best predictive value to design a risk calculator that can assist clinicians with risk stratification and outcome prediction.

Methods: Patients with a radiological diagnosis of ARVD referred to our tertiary renal centre were recruited into this prospective cohort study between 1986 and 2014. Primary clinical endpoints included: death, progression to end-stage kidney disease and cardiovascular events (CVE). A stepwise regression model was used to select variables with the most significant hazard ratio for each clinical endpoint. The risk calculator was designed using Hypertext Markup Language. Survival and CVE-free survival were estimated at 1, 5 and 10 years.

Results: In total, 872 patients were recruited into the Salford ARVD study with a median follow-up period of 54.9 months (interquartile range 20.2-96.0). Only models predicting death and CVE showed good performance (C-index >0.80). Survival probabilities obtained from the risk calculator show that most patients with ARVD have reduced long-term survival. Revascularization improved outcomes in patients with higher baseline estimated glomerular filtration rate and lower proteinuria but not in those with co-existing comorbidities and higher levels of baseline proteinuria.

Conclusions: Although this risk calculator requires further independent validation in other ARVD cohorts, this study shows that a small number of easily obtained variables can help predict clinical outcomes and encourage a patient-specific therapeutic approach.
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http://dx.doi.org/10.1093/ndt/gfy157DOI Listing
August 2019

The impact of outpatient acute kidney injury on mortality and chronic kidney disease: a retrospective cohort study.

Nephrol Dial Transplant 2019 03;34(3):493-501

Division of Renal Diseases and Hypertension, University of Minnesota, Minneapolis, MN, USA.

Background: Acute kidney injury (AKI) has been extensively studied in hospital settings. Limited data exist regarding outcomes for patients with outpatient AKI who are not subsequently admitted. We investigated whether outpatient AKI, defined by a 50% increase in creatinine (Cr), is associated with increased mortality and renal events.

Methods: In this retrospective study, outpatient serum Cr values from adults receiving primary care at a health system during an 18-month exposure period were used to categorize patients into one of five groups (no outpatient AKI, outpatient AKI with recovery, outpatient AKI without recovery, outpatient AKI without repeat Cr and no Cr). Principal outcomes of all-cause mortality and renal events (50% decline in estimated glomerular filtration rate to <30 mL/min/1.73 m2) were examined using Cox proportional hazards models.

Results: Among 384 869 eligible patients, 51% had at least one Cr measured during the exposure period. Outpatient AKI occurred in 1.4% of patients while hospital AKI occurred in only 0.3% of patients. The average follow-up was 5.3 years. Outpatient AKI was associated with an increased risk of all-cause mortality {adjusted hazard ratio [aHR] 1.90 [95% confidence interval (CI) 1.76-2.06]} and results were consistent across all AKI groups. Outpatient AKI was also associated with an increased risk of renal events [aHR 1.33 (95% CI 1.11-1.59)], even among those who recovered.

Conclusions: Outpatient AKI is more prevalent than inpatient AKI and is a risk factor for all-cause mortality and renal events, even among those who recover kidney function. Further research is necessary to determine risk factors and identify strategies for preventing outpatient AKI.
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http://dx.doi.org/10.1093/ndt/gfy036DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6399485PMC
March 2019

End-Stage Kidney Disease From Scleroderma in the United States, 1996 to 2012.

Kidney Int Rep 2018 Jan 18;3(1):148-154. Epub 2017 Sep 18.

Division of Renal Diseases and Hypertension, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA.

Introduction: Although the management of scleroderma continues to evolve, it is unknown whether the burden of end-stage kidney disease (ESKD) treated with maintenance renal replacement therapy from SD has changed.

Methods: We examined United States Renal Data System data (n = 1,677,303) for the years 1996 to 2012 to quantify the incidence and outcomes of ESKD from scleroderma treated with renal replacement therapy (n = 2398). Outcomes assessed through demography-matched scleroderma-positive/scleroderma-negative comparisons included recovery of kidney function, mortality, listing for transplant, renal transplantations, and graft failure.

Results: Overall ESKD rates from scleroderma were 0.5 per million per year. Adjusted incidence ratios fell over time, to 0.42 in 2012 (vs. 1996, 95% confidence interval [CI] = 0.32-0.54,  < 0.001). Adjusted incidence ratios for ESKD from scleroderma fell over time in both sexes, all age, race, and ethnicity categories except age < 20 years and Asian race, and in all regions of the United States. After initiating renal replacement therapy, patients with scleroderma had a greater likelihood of recovery of kidney function (hazards ratio [HR] = 2.67, 95% CI = 1.90-3.76,  < 0.001) and death (HR = 1.44, 95% CI = 1.34-1.54,  < 0.001) and a lower likelihood of transplantation (HR = 0.51, 95% CI = 0.44-0.59,  < 0.001) than demography-matched patients without scleroderma.

Conclusion: The incidence of ESKD from scleroderma appears to have declined in the United States since 1996. ESKD from scleroderma is associated with an enhanced likelihood of recovery of kidney function and death, a reduced likelihood of transplantation, and similar outcomes after transplantation.
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http://dx.doi.org/10.1016/j.ekir.2017.09.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5762953PMC
January 2018

Epidemiology and Risk Factors for Early Mortality After Dialysis Initiation.

Authors:
Robert N Foley

Semin Nephrol 2017 03;37(2):114-119

Department of Medicine, University of Minnesota, Minneapolis, MN. Electronic address:

Confronted with the decision to initiate dialysis, patients and caregivers often seek information about how expected survival chances evolve, both initially and afterward, providing the patient survives beyond arbitrary periods of time. Large registry data, used to examine these issues, may be subject to early ascertainment bias, such as those accruing from nonregistration of with end-stage kidney disease who die shortly after dialysis initiation and inclusion of patients with acute kidney injury with slower than typical recovery rates. Despite these caveats, available studies have suggested that mortality hazards are much higher in the first 3 months of renal replacement therapy. Prominent modifiable associations of early mortality include late referral to nephrology services, initial dialysis with vascular catheters, and, most problematically, higher glomerular filtration rates at initiation of renal replacement therapy. Despite their imperfections, currently available information is relatively user-unfriendly and could be better leveraged to help patients and treatment teams make better decisions.
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http://dx.doi.org/10.1016/j.semnephrol.2016.12.001DOI Listing
March 2017

Stable Angina in Advanced CKD.

Authors:
Robert N Foley

Am J Kidney Dis 2017 03;69(3):328-330

University of Minnesota, Minneapolis, Minnesota. Electronic address:

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http://dx.doi.org/10.1053/j.ajkd.2016.11.010DOI Listing
March 2017

Renal Function Profile in White Kidney Donors: The First 4 Decades.

J Am Soc Nephrol 2016 09 17;27(9):2885-93. Epub 2016 Feb 17.

Department of Surgery, University of Minnesota, Minneapolis, Minnesota.

Previous studies reported the risk of ESRD after kidney donation, but not the renal outcomes that precede ESRD. Here, we estimated the risk of proteinuria, reduced GFR, and ESRD in 3956 white kidney donors, assessed the contribution of postdonation hypertension and diabetes to these outcomes, and developed a risk calculator. After a mean±SD follow-up of 16.6±11.9 years, 215 (6.1%) donors developed proteinuria. Men had a higher risk of proteinuria (hazard ratio [HR], 1.56; 95% confidence interval [95% CI], 1.18 to 2.05; P<0.001) as did those with higher body mass index (HR, 1.10; 95% CI, 1.06 to 1.13; P<0.001). In all, 1410 (36%) donors reached an eGFR<60 ml/min per 1.73 m(2), and 112 (2.8%) donors had either an eGFR<30 ml/min per 1.73 m(2) or ESRD (28 donors developed ESRD). An eGFR<30 ml/min per 1.73 m(2) or ESRD associated with older age (HR, 1.07; 95% CI, 1.05 to 1.09; P<0.001), higher body mass index (HR, 1.08; 95% CI, 1.04 to 1.13; P<0.001), and higher systolic BP (HR, 1.02; 95% CI, 1.00 to 1.04; P=0.01) at donation. Postdonation diabetes and hypertension associated with a fourfold higher risk of proteinuria and a >2-fold higher risk of ESRD. Models predicting proteinuria and reduced eGFR performed well (C-index 0.77-1.00). In conclusion, severe reduction in GFR and ESRD after kidney donation were uncommon and were highly associated with postdonation diabetes and hypertension. Furthermore, information available before donation may predict long-term renal outcomes in white living kidney donors.
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http://dx.doi.org/10.1681/ASN.2015091018DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5004661PMC
September 2016

The Brain in Kidney Disease (BRINK) Cohort Study: Design and Baseline Cognitive Function.

Am J Kidney Dis 2016 Apr 29;67(4):593-600. Epub 2015 Dec 29.

Department of Neurology, Mayo Clinic, Rochester, MN.

Background: The Brain in Kidney Disease (BRINK) Study aims to identify mechanisms that contribute to increased risk for cognitive impairment in patients with chronic kidney disease (CKD). We describe the rationale, design, and methods of the study and report baseline recruitment and cognitive function results.

Study Design: Longitudinal observational cohort study of the epidemiology of cognitive impairment in CKD. The primary aim is to characterize the association between (1) baseline and incident stroke, white matter disease, estimated glomerular filtration rate (eGFR), inflammation, microalbuminuria, and dialysis initiation and (2) cognitive decline over 3 years in a CKD cohort with a mean eGFR<45 mL/min/1.73 m(2).

Setting & Participants: Community-dwelling participants 45 years or older recruited from 4 health systems into 2 groups: reduced eGFR, defined as eGFR<60 mL/min/1.73 m(2) (non-dialysis dependent), and control, defined as eGFR≥60 mL/min/1.73 m(2).

Predictor: eGFR group.

Outcomes: Performance on cognitive function tests and structural brain magnetic resonance imaging.

Measurements: Sequential cognitive and physical function testing, serum and urine biomarker measurement, and brain magnetic resonance images over 3 years.

Results: Of 554 participants, mean age was 69.3 years; 333, 88, and 133 had eGFRs<45 (non-dialysis dependent, nontransplantation), 45 to <60, and ≥60 (controls) mL/min/1.73 m(2), respectively. Mean eGFR in reduced-eGFR participants was 34.3 mL/min/1.73 m(2). Baseline cognitive performance was significantly associated with eGFR in all domains except language. Participants with eGFRs<30 mL/min/1.73 m(2) performed significantly worse than those with eGFRs≥30 mL/min/1.73 m(2) on tests of memory, processing speed, and executive function. Participants with reduced eGFRs overall scored worst on the Immediate Brief Visual-Spatial Memory Test-Revised.

Limitations: Healthy cohort bias, competing risk for death versus cognitive decline.

Conclusions: Cognitive function was significantly worse in participants with eGFRs<30 mL/min/1.73 m(2). Future BRINK analyses will measure risk factors for cognitive decline using the longitudinal data.
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http://dx.doi.org/10.1053/j.ajkd.2015.11.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5271565PMC
April 2016

ESRD due to Multiple Myeloma in the United States, 2001-2010.

J Am Soc Nephrol 2016 05 29;27(5):1487-94. Epub 2015 Oct 29.

Department of Medicine, University of Minnesota, Minneapolis, Minnesota; and Minneapolis Medical Research Foundation, Minneapolis, Minnesota

Although management of multiple myeloma has changed substantially in the last decade, it is unknown whether the burden of ESRD due to multiple myeloma has changed, or whether survival of patients with multiple myeloma on RRT has improved. Regarding ESRD due to multiple myeloma necessitating RRT in the United States, we evaluated temporal trends between 2001 and 2010 for demography-adjusted incidence ratios, relative to rates in 2001-2002, and mortality hazards from RRT initiation, relative to hazards in 2001-2002. In this retrospective cohort study, we used the US Renal Data System database (n=1,069,343), 2001-2010, to identify patients with ESRD due to multiple myeloma treated with RRT (n=12,703). Demography-adjusted incidence ratios of ESRD from multiple myeloma decreased between 2001-2002 and 2009-2010 in the overall population (demography-adjusted incidence ratio 0.82; 95% confidence interval, 0.79 to 0.86) and in most demographic subgroups examined. Mortality rates were 86.7, 41.4, and 34.4 per 100 person-years in the first 3 years of RRT, respectively, compared with 32.3, 20.6, and 21.3 in matched controls without multiple myeloma. Unadjusted mortality hazards ratios declined monotonically after 2004 to a value of 0.72; 95% confidence interval, 0.67 to 0.77 in 2009-2010, and declines between 2001-2002 and 2008-2009 were observed (P<0.05) in most demographic subgroups examined. Findings were similar when adjustment was made for demographic characteristics, comorbidity markers, and laboratory test values. These data suggest the incidence of RRT from multiple myeloma in the United States has decreased in the last decade, and clinically meaningful increases in survival have occurred for these patients.
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http://dx.doi.org/10.1681/ASN.2014090876DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4849810PMC
May 2016

United States Renal Data System public health surveillance of chronic kidney disease and end-stage renal disease.

Kidney Int Suppl (2011) 2015 Jun;5(1):2-7

Chronic Disease Research Group, Minneapolis Medical Research Foundation , Minneapolis, Minnesota, USA.

The United States Renal Data System (USRDS) began in 1989 through US Congressional authorization under National Institutes of Health competitive contracting. Its history includes five contract periods, two of 5 years, two of 7.5 years, and the fifth, awarded in February 2014, of 5 years. Over these 25 years, USRDS reporting transitioned from basic incidence and prevalence of end-stage renal disease (ESRD), modalities, and overall survival, as well as focused special studies on dialysis, in the first two contract periods to a comprehensive assessment of aspects of care that affect morbidity and mortality in the second two periods. Beginning in 1999, the Minneapolis Medical Research Foundation investigative team transformed the USRDS into a total care reporting system including disease severity, hospitalizations, pediatric populations, prescription drug use, and chronic kidney disease and the transition to ESRD. Areas of focus included issues related to death rates in the first 4 months of treatment, sudden cardiac death, ischemic and valvular heart disease, congestive heart failure, atrial fibrillation, and infectious complications (particularly related to dialysis catheters) in hemodialysis and peritoneal dialysis patients; the burden of congestive heart failure and infectious complications in pediatric dialysis and transplant populations; and morbidity and access to care. The team documented a plateau and decline in incidence rates, a 28% decline in death rates since 2001, and changes under the 2011 Prospective Payment System with expanded bundled payments for each dialysis treatment. The team reported on Bayesian methods to calculate mortality ratios, which reduce the challenges of traditional methods, and introduced objectives under the Health People 2010 and 2020 national health care goals for kidney disease.
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http://dx.doi.org/10.1038/kisup.2015.2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4455192PMC
June 2015

Randomized controlled trials 7: Analysis and interpretation of quality-of-life scores.

Methods Mol Biol 2015 ;1281:261-72

Division of Renal Diseases and Hypertension, University of Minnesota, Minneapolis, MN, USA,

Quality-of-life (QoL) outcomes are important elements of randomized controlled trials. The instruments for measurement of QoL vary but usually multiple comparisons are possible, a concern that can be offset by prespecifying the outcomes of interest. Missing data may threaten the validity of QoL assessments in trials. Therefore familiarity with the strategies used to account for missing data is necessary. Measures that incorporate both survival and QoL are helpful for treatment decisions. The definition of minimal clinically important differences in QoL scores is important and often derived using inadequate methods.
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http://dx.doi.org/10.1007/978-1-4939-2428-8_15DOI Listing
November 2015

Randomized controlled trials 2: Analysis.

Authors:
Robert N Foley

Methods Mol Biol 2015 ;1281:177-90

Division of Renal Diseases and Hypertension, University of Minnesota, Minneapolis, MN, USA,

When analyzing the results of a trial the primary outcome variable must be kept in clear focus. In the analysis plan consideration must be given to comparing the characteristics of the subjects, taking account of differences in these characteristics, intention to treat analysis, interim analyses and stopping rules, mortality comparisons, composite outcomes, research design including run-in periods, factorial, stratified, and crossover designs, number needed to treat, power issues, multivariate modeling, and hypothesis-generating analyses.
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http://dx.doi.org/10.1007/978-1-4939-2428-8_10DOI Listing
November 2015

End-stage renal disease from hemolytic uremic syndrome in the United States, 1995-2010.

Hemodial Int 2015 Oct 17;19(4):521-30. Epub 2015 Feb 17.

Chronic Disease Research Group, Minneapolis Medical Research Foundation, Minneapolis, Minnesota, USA.

Management of hemolytic uremic syndrome (HUS) has evolved rapidly, and optimal treatment strategies are controversial. However, it is unknown whether the burden of end-stage renal disease (ESRD) from HUS has changed, and outcomes on dialysis in the United States are not well described. We retrospectively examined data for patients initiating maintenance renal replacement therapy (RRT) (n = 1,557,117), 1995-2010, to define standardized incidence ratios (SIRs) and outcomes of ESRD from HUS) (n = 2241). Overall ESRD rates from HUS in 2001-2002 were 0.5 cases/million per year and were higher for patients characterized by age 40-64 years (0.6), ≥65 years (0.7), female sex (0.6), and non-Hispanic African American race (0.7). Standardized incidence ratios remained unchanged (P ≥ 0.05) between 2001-2002 and 2009-2010 in the overall population. Compared with patients with ESRD from other causes, patients with HUS were more likely to be younger, female, white, and non-Hispanic. Over 5.4 years of follow-up, HUS patients differed from matched controls with ESRD from other causes by lower rates of death (8.3 per 100 person-years in cases vs. 10.4 in controls, P < 0.001), listing for renal transplant (7.6 vs. 8.6 per 100 person-years, P = 0.04), and undergoing transplant (6.9 vs. 9 per 100 person-years, P < 0.001). The incidence of ESRD from HUS appears not to have risen substantially in the last decade. However, given that HUS subtypes could not be determined in this study, these findings should be interpreted with caution.
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http://dx.doi.org/10.1111/hdi.12281DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4539282PMC
October 2015

End-stage renal disease attributed to acute tubular necrosis in the United States, 2001-2010.

Am J Nephrol 2015 23;41(1):1-6. Epub 2015 Jan 23.

Chronic Disease Research Group, Minneapolis Medical Research Foundation, Minneapolis, Minn., USA.

Background/aims: Though end-stage renal disease (ESRD) is increasingly attributed to acute tubular necrosis (ATN), contemporary trends in the rates of incidence and recovery of renal function are poorly defined. Hence, we set out to describe the clinical epidemiology of ESRD due to ATN between 2001 and 2010.

Methods: We examined United States Renal Data System data (n = 1,070,490) for 2001 through 2010 to calculate the incidence rates and rates of renal recovery and death for patients with ESRD due to ATN treated with renal replacement therapy (RRT, n = 27,603).

Results: Standardized incidence ratios increased between 2001-2002 and 2009-2010 in the overall population (ratio 2.14), having risen in all demographic subgroups examined. Recovery of renal function was more likely in patients with ATN than in matched controls (cumulative incidence 23% vs. 2% at 12 weeks, 34% vs. 4% at 1 year), as was death (cumulative incidence 38% vs. 27% at 1 year). Hazards ratios for renal recovery increased stepwise with year of RRT inception to 1.34 (95% confidence interval 1.24-1.45) for 2009-2010 (vs. 2001-2002). In contrast, hazards ratios for death declined stepwise to 0.83 (0.79-0.87) in 2009-2010.

Conclusion: While the incidence of ESRD attributed to ATN has increased, prospects of renal recovery and survival have also increased. Despite substantial mortality risk on RRT, renal recovery is not a rare occurrence.
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http://dx.doi.org/10.1159/000369832DOI Listing
September 2015

ESRD from lupus nephritis in the United States, 1995-2010.

Clin J Am Soc Nephrol 2015 Feb 22;10(2):251-9. Epub 2014 Dec 22.

Chronic Disease Research Group, Minneapolis Medical Research Foundation, Minneapolis, Minnesota, and Department of Medicine, University of Minnesota, Minneapolis, Minnesota

Background And Objectives: While ESRD from lupus nephritis (ESLN) increased in the United States after the mid-1990s and racial disparities were apparent, current trends are unknown.

Design, Setting, Participants, & Measurements: Retrospective US Renal Data System data (n=1,557,117) were used to calculate standardized incidence ratios (standardized to 1995-1996) and outcomes of ESLN (n=16,649). For events occurring after initiation of RRT, follow-up ended on June 30, 2011.

Results: Overall ESLN rates (95% confidence intervals [95% CIs]) in 1995-1996 were 3.1 (2.9 to 3.2) cases per million per year. Rates were higher for subgroups characterized by African-American race (11.1 [95% CI, 10.3 to 11.9]); other race (4.9 [95% CI, 4.0 to 5.8]); female sex (4.9 [95% CI, 4.6 to 5.2]); and ages 20-29 years (4.9 [95% CI, 4.4 to 5.4]), 30-44 years (4.6 [95% CI, 4.2 to 5.0]), and 45-64 years (4.0 [95% CI, 3.7 to 4.4]). Standardized incidence ratios for the overall population in subsequent biennia were 1.19 (1.14 to 1.24) in 1997-1998, 1.17 (1.12 to 1.22) in 1999-2000, 1.17 (1.12 to 1.22) in 2001-2002, 1.21 (1.16 to 1.26) in 2003-2004, 1.18 (1.13 to 1.23) in 2005-2006, 1.16 (1.11 to 1.21) in 2007-2008, and 1.05 (1.01 to 1.09) in 2009-2010, respectively. During a median (interquartile range) follow-up of 4.4 (6.3) years, 42.6% of patients with ESLN died, 45.3% were listed for renal transplant, and 28.7% underwent transplantation. Patients with ESLN were more likely than matched controls to be listed for and to undergo transplantation, and mortality rates were similar. Among patients with ESLN, African Americans were less likely to undergo transplantation (adjusted hazard ratio, 0.54 [0.51 to 0.58]) and more likely to die prematurely (adjusted hazard ratio, 1.23 [1.17 to 1.30]).

Conclusions: While ESLN appears to have stopped increasing in the last decade, racial disparities in outcomes persist.
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http://dx.doi.org/10.2215/CJN.02350314DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4317731PMC
February 2015

ESRD from autosomal dominant polycystic kidney disease in the United States, 2001-2010.

Am J Kidney Dis 2014 Oct 16;64(4):592-9. Epub 2014 Aug 16.

Department of Medicine, University of Minnesota, Minneapolis, MN; United States Renal Data System, Minneapolis Medical Research Foundation, Minneapolis, MN. Electronic address:

Background: Autosomal dominant polycystic kidney disease (ADPKD) is amenable to early detection and specialty care. Thus, while important to patients with the condition, end-stage renal disease (ESRD) from ADPKD also may be an indicator of the overall state of nephrology care.

Study Design: Retrospective cohort study of temporal trends in ESRD from ADPKD and pre-renal replacement therapy (RRT) nephrologist care, 2001-2010 (n = 23,772).

Setting & Participants: US patients who initiated maintenance RRT from 2001 through 2010 (n = 1,069,343) from US Renal Data System data.

Predictor: ESRD from ADPKD versus from other causes for baseline characteristics and clinical outcomes; interval 2001-2005 versus 2006-2010 for comparisons of cohort of patients with ESRD from ADPKD.

Outcomes: Death, wait-listing for kidney transplant, kidney transplantation.

Measurements: US census data were used as population denominators. Poisson distribution was used to compute incidence rates (IRs). Incidence ratios were standardized to rates in 2001-2002 for age, sex, and race/ethnicity. Patients with and without ADPKD were matched to compare clinical outcomes. Poisson regression was used to calculate IRs and adjusted HRs for clinical events after inception of RRT.

Results: General population incidence ratios in 2009-2010 were unchanged from 2001-2002 (incidence ratio, 1.02). Of patients with ADPKD, 48.1% received more than 12 months of nephrology care before RRT; preemptive transplantation was the initial RRT in 14.3% and fistula was the initial hemodialysis access in 35.8%. During 4.9 years of follow-up, patients with ADPKD were more likely to be listed for transplantation (IR, 11.7 [95% CI, 11.5-12.0] vs 8.4 [95% CI, 8.2-8.7] per 100 person-years) and to undergo transplantation (IR, 9.8 [95% CI, 9.5-10.0] vs 4.8 [95% CI, 4.7-5.0] per 100 person-years) and less likely to die (IR, 5.6 [95% CI, 5.4-5.7] vs 15.5 [95% CI, 15.3-15.8] per 100 person-years) than matched controls without ADPKD.

Limitations: Retrospective nonexperimental registry-based study of associations; cause-and-effect relationships cannot be determined.

Conclusions: Although outcomes on dialysis therapy are better for patients with ADPKD than for those without ADPKD, access to predialysis nephrology care and nondeclining ESRD rates may be a cause for concern.
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http://dx.doi.org/10.1053/j.ajkd.2014.05.020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4396817PMC
October 2014

Relative safety of peginesatide and epoetin alfa.

Pharmacoepidemiol Drug Saf 2014 Oct 6;23(10):1003-11. Epub 2014 Jun 6.

Chronic Disease Research Group, Minneapolis Medical Research Foundation, Minneapolis, MN, USA.

Purpose: Peginesatide, a long-acting erythropoiesis-stimulating agent, was recalled in February 2013 following reports of serious and sometimes fatal hypersensitivity reactions in dialysis patients who received a first dose. We assessed the relative risks of mortality and morbidity in peginesatide-treated and matched epoetin alfa-treated patients.

Methods: From standardized extracts of paid Medicare claims in 2012 and 2013, we identified dialysis patients treated with peginesatide or epoetin between 1 July 2012 and 28 February 2013. For each peginesatide-treated patient, we identified with propensity score matching two epoetin-treated control patients. Patients were followed for up to 2 days after the first peginesatide dose or the referent epoetin dose for death or hospitalization as a result of cardiovascular morbidity or symptoms (composite event), all-cause hospitalization, and emergency room care.

Results: We identified 15 633 peginesatide-treated patients and 31 266 matched epoetin-treated controls. On the day of dose administration, 19 composite events occurred with peginesatide (incidence, 0.12%) and 14 with epoetin (0.04%); the hazard ratio was 2.7 (95% confidence interval, 1.4-5.4). With follow-up for 1 and 2 subsequent days, hazard ratios were 1.6 (1.0-2.4) and 1.5 (1.1-2.0), respectively. Corresponding hazard ratios were larger among hemodialysis patients with neither intravenous antibiotic nor intravenous iron exposure on the day of dose administration. Hazard ratios for all-cause hospitalization and emergency room care exceeded 1 on and after the day of dose administration.

Conclusions: Relative to administration of epoetin alfa, first administration of peginesatide in dialysis patients was acutely associated with higher risk of death or hospitalization as a result of cardiovascular morbidity or symptoms.
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http://dx.doi.org/10.1002/pds.3655DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7510845PMC
October 2014

Early mortality in patients starting dialysis appears to go unregistered.

Kidney Int 2014 Aug 12;86(2):392-8. Epub 2014 Feb 12.

1] United States Renal Data System, Minneapolis Medical Research Foundation, Minneapolis, Minnesota, USA [2] Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA.

Clinical experience suggests a heightened risk associated with the transition to maintenance dialysis but few national studies have systematically examined early mortality trajectories. Here we calculated weekly mortality rates in the first year of treatment for 498,566 adults initiating maintenance dialysis in the United States (2005-2009). Mortality rates were initially unexpectedly low, peaked at 37.0 per 100 person-years in week 6, and declined steadily to 14.8 by week 51. In both early (weeks 7-12) and later (weeks 13-51) time frames, multivariate mortality associations included older age, female, Caucasian, non-Hispanic ethnicity, end-stage renal disease (ESRD) from hypertension and acute tubular necrosis, ischemic heart disease, estimated glomerular filtration rate of 15 ml/min per 1.73 m(2) or more, shorter duration of nephrologist care, and hemodialysis, especially with a catheter. For early mortality risk, adjusted hazard ratios of 2 or more were seen with age over 65 (5.80 vs. under 40 years), hemodialysis with a catheter (2.73 vs. fistula), and age 40-64 (2.33). For later mortality risk, adjusted hazard ratios of 2 or more were seen with age over 65 (4.32 vs. under 40 years), hemodialysis with a catheter (2.10 vs. fistula), and age 40-64 (2.00). Thus, low initial mortality rates question the accuracy of data collected and are consistent with deaths occurring in the early weeks after starting dialysis not being registered with the United States Renal Data System.
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http://dx.doi.org/10.1038/ki.2014.15DOI Listing
August 2014

Agreement of reported vascular access on the medical evidence report and on medicare claims at hemodialysis initiation.

BMC Nephrol 2014 Feb 8;15:30. Epub 2014 Feb 8.

United States Renal Data System, Minneapolis Medical Research Foundation, 914 South 8th Street, Suite S4,100, Minneapolis, Minnesota 55404, USA.

Background: The choice of vascular access type is an important aspect of care for incident hemodialysis patients. However, data from the Centers for Medicare & Medicaid Services (CMS) Medical Evidence Report (form CMS-2728) identifying the first access for incident patients have not previously been validated. Medicare began requiring that vascular access type be reported on claims in July 2010. We aimed to determine the agreement between the reported vascular access at initiation from form CMS-2728 and from Medicare claims.

Methods: This retrospective study used a cohort of 9777 patients who initiated dialysis in the latter half of 2010 and were eligible for Medicare at the start of renal replacement therapy to compare the vascular access type reported on form CMS-2728 with the type reported on Medicare outpatient dialysis claims for the same patients. For each patient, the reported access from each data source was compiled; the percent agreement represented the percent of patients for whom the access was the same. Multivariate logistic analysis was performed to identify characteristics associated with the agreement of reported access.

Results: The two data sources agreed for 94% of patients, with a Kappa statistic of 0.83, indicating an excellent level of agreement. Further, we found no evidence to suggest that agreement was associated with the patient characteristics of age, sex, race, or primary cause of renal failure.

Conclusion: These results suggest that vascular access data as reported on form CMS-2728 are valid and reliable for use in research studies.
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http://dx.doi.org/10.1186/1471-2369-15-30DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3922277PMC
February 2014

Cardiac biomarkers and health-related quality of life in new hemodialysis patients without symptomatic cardiac disease.

Can J Kidney Health Dis 2014 15;1:16. Epub 2014 Jul 15.

Division of Nephrology, Health Sciences Center, Memorial University, St. John's, Newfoundland A1B 3 V6 Canada.

Background: Health Related Quality of Life (HRQOL) is impaired in hemodialysis patients and cardiac biomarkers are elevated, but their relationship is uncertain.

Objectives: To determine whether the cardiac biomarkers, troponin T and N terminal pro-B type natriuretic peptide (NT-proBNP), predict deterioration in the physical domains of HRQOL.

Design: A prospective cohort study of patients in a randomized controlled clinical trial of correction of anemia with erythropoietin.

Setting: Multiple hemodialysis centers located throughout Canada and Europe.

Participants: Patients who started maintenance hemodialysis within the previous 3-18 months, with no clinical evidence or prior history of symptomatic cardiac failure or ischemic heart disease, and left ventricular volume < 100 ml/m(2).

Measurements:

Predictor: Baseline concentrations of Troponin T and NT-proBNP.

Outcomes: Physical function and vitality scores using the SF-36 questionnaire and fatigue scores using the FACIT questionnaire at baseline and after 24, 48, and 96 weeks follow-up.

Methods: Univariate analysis of the association between baseline variables and baseline HRQOL scores and change in scores over time was undertaken using linear regression. Multivariate models were created using multiple linear regression, and it was pre-specified that these include the variables which were associated with the outcome at a p < 0.05 in the univariate regression.

Results: Baseline median (interquartile range) physical function score was 70 (50-85), vitality 55 (40-75), and fatigue 73 (58-86). The 75th percentile for Troponin T was 0.05 ng/mL and for NT-proBNP 652 ng/mL. High Troponin T levels were significantly associated with deterioration in the 3 physical domains, independent of other risk factors, whereas high NT-proBNP were not associated. In multivariate models baseline Troponin T > 0.05 ng/mL were significantly associated with the change from baseline to 96 weeks follow-up for SF-36 vitality and FACIT-fatigue scores, and approached statistical significance for SF-36 physical function (0.056).

Limitations: Not possible to confirm whether Troponin T associations were independent of subsequent cardiac events.

Conclusions: In hemodialysis patients without prior symptomatic cardiac disease and without a dilated left ventricle at baseline, elevated baseline Troponin T levels, but not NT-pro BNP, were independently associated with deterioration in the physical domains of HRQOL.
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http://dx.doi.org/10.1186/2054-3581-1-16DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4452142PMC
June 2015

Perihospitalization patterns of hemoglobin levels and erythropoiesis-stimulating agent doses in US hemodialysis patients, 1998-2009.

Hemodial Int 2014 Jan 17;18(1):24-31. Epub 2013 Oct 17.

Chronic Disease Research Group, Minneapolis Medical Research Foundation, Minneapolis, Minnesota, USA; Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA.

Anemia management in hemodialysis patients is of primary importance for clinicians and dialysis providers. Through a retrospective claims analysis, we studied prevalent US hemodialysis patients 1998-2009, and examined patterns of hemoglobin levels and erythropoiesis-stimulating agent (ESA, epoetin [EPO], and darbepoetin [DPO] ) doses surrounding hospitalization events. Medicare outpatient claims were used to determine monthly ESA doses and associated hemoglobin levels. ESA dose trajectories were defined with repeated measures models incorporating an autoregressive covariance matrix that compared subsequent measurements with the index month of hospitalization, with variance component covariance matrices chosen for pair-wise comparisons. Regarding prehospitalization hemoglobin levels, a biphasic pattern occurred in both the EPO (1998-2009, n = 161,242) and DPO (2004-2009, n = 4391) populations; levels rose from 1998 to 2004, fell thereafter in the EPO population, and fell after 2006 or 2007 in the DPO population. In the EPO population, the proportions of patients with hemoglobin less than 10 g/dL were 30.1% in 1998, 14.5% in 2004, and 28.3% in 2009; corresponding values for the DPO population were 21.0% in 2004 and 31.6% in 2009. While some degree of year-to-year variability occurred, EPO dose trends were less pronounced, with an apparent peak in 2004 followed by a modest decline; trends were similar for DPO. Trends in EPO dose trajectories did not completely parallel those for hemoglobin level; while EPO doses increased yearly up to 2004, doses stabilized, but did not materially decrease after 2004. No definite annual trends for DPO dose trajectories were apparent.
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http://dx.doi.org/10.1111/hdi.12090DOI Listing
January 2014

High-risk clinical presentations in atherosclerotic renovascular disease: prognosis and response to renal artery revascularization.

Am J Kidney Dis 2014 Feb 26;63(2):186-97. Epub 2013 Sep 26.

Vascular Research Group, Manchester Academic Health Sciences Centre, University of Manchester, Salford Royal NHS Foundation Trust, Salford, United Kingdom. Electronic address:

Background: Current trial data may not be directly applicable to patients with the highest risk presentations of atherosclerotic renovascular disease, including flash pulmonary edema, rapidly declining kidney function, and refractory hypertension. We consider the prognostic implications of these presentations and response to percutaneous revascularization.

Study Design: Single-center prospective cohort study; retrospectively analyzed.

Setting & Participants: 467 patients with renal artery stenosis ≥50%, managed according to clinical presentation and physician/patient preference.

Predictors: Presentation with flash pulmonary edema (n = 37 [7.8%]), refractory hypertension (n = 116 [24.3%]), or rapidly declining kidney function (n = 46 [9.7%]) compared to low-risk presentation with none of these phenotypes (n = 230 [49%]). Percutaneous revascularization (performed in 32% of flash pulmonary edema, 28% of rapidly declining kidney function, and 28% of refractory hypertension patients) compared to medical management.

Outcomes: Death, cardiovascular (CV) event, end-stage kidney disease.

Results: During a median follow-up of 3.8 (IQR, 1.8-5.8) years, 55% died, 33% had a CV event, and 18% reached end-stage kidney disease. In medically treated patients, flash pulmonary edema was associated with increased risk of death (HR, 2.2; 95% CI, 1.4-3.5; P < 0.001) and CV event (HR, 3.1; 95% CI, 1.7-5.5; P < 0.001), but not end-stage kidney disease, compared to the low-risk phenotype. No increased risk for any end point was observed in patients presenting with rapidly declining kidney function or refractory hypertension. Compared to medical treatment, revascularization was associated with reduced risk for death (HR, 0.4; 95% CI, 0.2-0.9; P = 0.01), but not CV event or end-stage kidney disease, in patients presenting with flash pulmonary edema. Revascularization was not associated significantly with reduced risk for any end point in rapidly declining kidney function or refractory hypertension. When these presentations were present in combination (n = 31), revascularization was associated with reduced risk for death (HR, 0.15; 95% CI, 0.02-0.9; P = 0.04) and CV event (HR, 0.23; 95% CI, 0.1-0.6; P = 0.02).

Limitations: Observational study; retrospective analysis; potential treatment bias.

Conclusions: This analysis supports guidelines citing flash pulmonary edema as an indication for renal artery revascularization in atherosclerotic renovascular disease. Patients presenting with a combination of rapidly declining kidney function and refractory hypertension also may benefit from revascularization and may represent a subgroup worthy of further investigation in more robust trials.
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http://dx.doi.org/10.1053/j.ajkd.2013.07.020DOI Listing
February 2014
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