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author:("jar, Bernard")
1.  Comparison of Life Participation Activities Among Adults Treated by Hemodialysis, Peritoneal Dialysis, and Kidney Transplantation: A Systematic Review 
A comprehensive assessment of the association of patients’ renal replacement therapy (RRT) modality on their participation in life activities (physical function, travel, recreation, freedom, work) is needed.
Study Design
Systematic review of peer-reviewed published studies.
Setting & Population
Adults undergoing RRT (hemodialysis, peritoneal dialysis, or transplantation).
Selection Criteria for Studies
We searched PubMed, Cochrane Library, and EMBASE from January 1980 through April 2012 for English-language articles that compared participation in life activities among patients receiving 1) hemodialysis compared with peritoneal dialysis, 2) hemodialysis compared with kidney transplantation, or 3) peritoneal dialysis compared with kidney transplantation.
RRT modality.
Reported rates of physical function, travel, recreation, freedom, and work-related activities by RRT modality.
A total of 46 studies (6 prospective cohort, 38 cross-sectional, and 2 pre-post transplantation) provided relevant comparisons of life participation activities among patients treated with hemodialysis, peritoneal dialysis, and kidney transplantation. Studies were conducted from 1985 to 2011 among diverse patient populations in 16 distinct locations. A majority of studies reported greater life participation rates among patients with kidney transplants compared to patients receiving either hemodialysis or peritoneal dialysis. In contrast, a majority of studies reported no differences in outcomes between patients receiving hemodialysis and patients receiving peritoneal dialysis. These results were consistent throughout the study period, across diverse populations, and among the subset of studies that performed appropriate adjustments for potential confounding factors.
Many studies included in the review had significant design weaknesses.
Evidence suggests patients with kidney transplants may experience better rates of life participation compared to patients receiving dialysis, while patients receiving hemodialysis and patients receiving peritoneal dialysis may experience similar rates of life participation. Rigorously performed studies are needed to better inform patients about the association of RRT on these important patient reported outcomes.
PMCID: PMC3809150  PMID: 23725972
dialysis; ESRD treatment; kidney transplantation; physical functioning; quality of life; social participation
2.  Association of Serum Bicarbonate With Risk of Renal and Cardiovascular Outcomes in CKD: A Report From the Chronic Renal Insufficiency Cohort (CRIC) Study 
The purpose of this study is to evaluate serum bicarbonate as a risk factor for renal outcomes, cardiovascular events and mortality in patients with chronic kidney disease (CKD).
Study Design
Observational cohort study.
Setting & Participants
3939 participants with CKD stages 2-4 who enrolled in the Chronic Renal Insufficiency Cohort (CRIC) between June 2003 - December 2008.
Serum bicarbonate.
Renal outcomes, defined as end-stage renal disease (either initiation of dialysis or kidney transplantation) or 50% reduction in eGFR; atherosclerotic events (myocardial infarction, stroke, peripheral arterial disease); congestive heart failure events; and death.
Time to event.
The mean eGFR was 44.8 ± 16.8 (SD) mL/min/1.73 m2, and the median serum bicarbonate was 24 (IQR, 22-26) mEq/L. During a median follow-up of 3.9 years, 374 participants died, 767 had a renal outcome, and 332 experienced an atherosclerotic event and 391 had a congestive heart failure event. In adjusted analyses, the risk of developing a renal endpoint was 3% lower per mEq/L increase in serum bicarbonate (HR, 0.97; 95% CI, 0.94-0.99; p=0.01). The association was stronger for participants with eGFR> 45ml/min/1.73m2 (HR, 0.91; 95%CI, 0.85-0.97; p=0.004). The risk of heart failure increased by 14% (HR, 1.14; 95%CI, 1.03-1.26; p=0.02) per mEq/L increase in serum bicarbonate over 24 mEq/L. Serum bicarbonate was not independently associated with atherosclerotic events (HR, 0.99; 95%CI, 0.95-1.03; p=0.6) and all-cause mortality (HR, 0.98; 95%CI, 0.95-1.02; p=0.3).
Single measurement of sodium bicarbonate.
In a cohort of participants with CKD, low serum bicarbonate was an independent risk factor for kidney disease progression, particularly for participants with preserved kidney function. The risk of heart failure was higher at the upper extreme of serum bicarbonate. There was no association between serum bicarbonate and all-cause mortality or atherosclerotic events.
PMCID: PMC3701754  PMID: 23489677
metabolic acidosis; serum bicarbonate; chronic kidney disease; cardiovascular morbidity
3.  Hemolysis as a rare but potentially life-threatening complication of hemodialysis: a case report 
BMC Research Notes  2014;7:475.
The burden of end-stage renal disease (ESRD) in the United States has increased dramatically over the past 30 years with almost 613,000 patients receiving renal replacement therapy in 2011. That same year, more than 112,000 new patients initiated dialysis with 92% of them receiving hemodialysis (HD). These patients experience significant morbidity and mortality with very frequent emergency room visits. Acute hemolysis associated with HD is a rare complication; however, if it’s not recognized early and managed adequately, it can be associated with life-threatening complications such as hyperkalemia and even myocardial infarction.
Case presentation
66-year-old African-American female with a history of ESRD secondary to hypertension developed a blood infiltration on the arterial side of her arteriovenous fistula followed by sudden onset of diffuse abdominal pain with nausea and vomiting during her regular HD treatment. She was referred to the emergency department where she was found to have shortness of breath with improved gastrointestinal symptoms. Her initial work-up revealed a severe anemia with a hematocrit of 10%. Further work-up revealed massive hemolysis, likely mechanical in nature and believed to be induced by malpositioning of her HD needle in the fistula. Her hospital course was complicated by rhabdomyolysis and acute myocardial infarction thought to be secondary to supply–demand ischemia in the setting of her profound anemia. Within a week, she eventually had a full recovery.
It is extremely important for physicians and particularly emergency department physicians to be aware of this potentially life-threatening complication of HD and have a high index of suspicion in the setting of acute anemia with hemolysis in this population.
PMCID: PMC4119419  PMID: 25065406
Hemolysis; Hemodialysis; Anemia; Complications; Hyperkalemia; Myocardial infarction
4.  Serum Fructosamine and Glycated Albumin and Risk of Mortality and Clinical Outcomes in Hemodialysis Patients 
Diabetes Care  2013;36(6):1522-1533.
Assays for serum total glycated proteins (fructosamine) and the more specific glycated albumin may be useful indicators of hyperglycemia in dialysis patients, either as substitutes or adjuncts to standard markers such as hemoglobin A1c, as they are not affected by erythrocyte turnover. However, their relationship with long-term outcomes in dialysis patients is not well described.
We measured fructosamine and glycated albumin in baseline samples from 503 incident hemodialysis participants of a national prospective cohort study, with enrollment from 1995–1998 and median follow-up of 3.5 years. Outcomes were all-cause and cardiovascular disease (CVD) mortality and morbidity (first CVD event and first sepsis hospitalization) analyzed using Cox regression adjusted for demographic and clinical characteristics, and comorbidities.
Mean age was 58 years, 64% were white, 54% were male, and 57% had diabetes. There were 354 deaths (159 from CVD), 302 CVD events, and 118 sepsis hospitalizations over follow-up. Both fructosamine and glycated albumin were associated with all-cause mortality; adjusted HR per doubling of the biomarker was 1.96 (95% CI 1.38–2.79) for fructosamine and 1.40 (1.09–1.80) for glycated albumin. Both markers were also associated with CVD mortality [fructosamine 2.13 (1.28–3.54); glycated albumin 1.55 (1.09–2.21)]. Higher values of both markers were associated with trends toward a higher risk of hospitalization with sepsis [fructosamine 1.75 (1.01–3.02); glycated albumin 1.39 (0.94–2.06)].
Serum fructosamine and glycated albumin are risk factors for mortality and morbidity in hemodialysis patients.
PMCID: PMC3661814  PMID: 23250799
5.  Frailty as a Novel Predictor of Mortality and Hospitalization in Hemodialysis Patients of All Ages 
To quantify the prevalence of frailty in adult patients of all ages undergoing chronic hemodialysis, its relationship to comorbidity and disability, and its association with adverse outcomes of mortality and hospitalization.
Prospective cohort study.
Single hemodialysis center in Baltimore, Maryland.
146 prevalent hemodialysis patients enrolled between January 2009 and March 2010 and followed through August 2012.
Frailty, comorbidity, and disability on enrollment into the study and subsequent mortality and hospitalizations.
At enrollment, 50.0% of older (age≥65) and 35.4% of younger (age<65) hemodialysis patients were frail; 35.9% and 29.3% were intermediately frail, respectively. The 3-year mortality was 16.2% for non frail, 34.4% for intermediately frail, and 40.2% for frail participants. Intermediate frailty and frailty were associated with a 2.68-fold (95% CI: 1.02-7.07, P=0.046) and 2.60-fold (95%CI: 1.04-6.49, P=0.041) higher risk of death independent of age, sex, comorbidity, and disability. In the year after enrollment, median number of hospitalizations was 1 (IQR 0-3). The proportion with 2 or more hospitalizations was 28.2% for non frail, 25.5% for intermediately frail, and 42.6% for frail participants. While intermediate frailty was not associated with the number of hospitalizations (RR=0.76, 95%CI:0.49-1.16, P=0.21), frailty was associated with a 1.43-fold (95%CI:1.00-2.03, P=0.049) higher number of hospitalizations independent of age, sex, comorbidity, and disability. The association of frailty with mortality and hospitalizations did not differ between older and younger participants (Interaction P=0.64 and P=0.14, respectively).
Adults of all ages undergoing hemodialysis have a very high prevalence of frailty, more than 5-fold higher than community dwelling older adults. In this population, regardless of age, frailtyis a strong, independent predictor of mortality and number of hospitalizations.
PMCID: PMC3938084  PMID: 23711111
Frailty; hemodialysis; mortality; hospitalization
6.  Incidental findings on cardiac computed tomography in incident hemodialysis patients: the predictors of arrhythmic and cardiovascular events in end-stage renal disease (PACE) study 
BMC Nephrology  2014;15:68.
This is the first study that has examined non-cardiac incidental findings in research cardiac computed tomography (CT) of hemodialysis patients and their relationship with patient characteristics.
We performed a cross-sectional analysis in the Predictors of Arrhythmic and Cardiovascular Events in End-Stage Renal Disease (PACE) study, a prospective cohort study on incident hemodialysis patients. Non-cardiac structures in the cardiac CT scan were reviewed and evaluated. The type and frequencies of non-cardiac incidental CT findings were summarized. Univariate and multivariate logistic regression were performed to analyze the associations between gender, older age, obesity, history of cardiovascular disease (CVD), smoking status, history of chronic pulmonary disease and history of cancer with presence of any incidental CT findings and, separately, pulmonary nodules.
Among the 260 participants, a total of 229 non-cardiac incidental findings were observed in 145 participants (55.8% of all participants). Of these findings, pulmonary nodules were the most common incidental finding (24.2% of all findings), and 41.3% of them requiring further follow-up imaging per radiology recommendation. Vascular and gastrointestinal findings occurred in 11.8% and 15.3% of participants, respectively. Participants 65 years or older had a higher odds of any incidental findings (Odds Ratio (OR) =2.55; 95% Confidence Intervals (CI) 1.30, 4.99) and pulmonary nodules (OR = 4.80; 95% CI 2.51, 9.18). Prior history of CVD was independently and significantly associated with any incidental findings (OR = 2.00; 95% CI 1.19, 3.40); but not with the presence of pulmonary nodules.
We demonstrate that the prevalence of incidental findings by cardiac CT scanning is extremely high among patients on hemodialysis. Further investigations to follow-up on the high occurrence of incidental findings during our research study and potentially clinical studies raises important practical, ethical and medico-legal issues that need to be carefully considered in research projects using imaging studies.
PMCID: PMC4019788  PMID: 24885570
Incidental findings; Cardiac; Computed tomography; Hemodialysis; Prevalence; Pulmonary nodule
7.  Effectiveness of Educational and Social Worker Interventions to Activate Patients’ Discussion and Pursuit of Preemptive Living Donor Kidney Transplantation: A Randomized Controlled Trial 
Many patients with chronic kidney disease (CKD) have difficulties becoming actively engaged in the pursuit of pre-emptive living donor kidney transplantation.
Study Design
The Talking About Live Kidney Donation (TALK) study was a randomized controlled trial of the effectiveness of educational and social worker interventions designed to encourage early discussions and active pursuit of pre-emptive LKT among patients with progressive CKD.
Setting & Participants
We recruited participants with progressive CKD from academically affiliated nephrology practices in Baltimore, Maryland.
Participants randomly received 1) “Usual Care” (routine care with their nephrologists), 2) “TALK Education” intervention (video and booklet), or the 3) “TALK Social Worker” intervention (video and booklet plus patient and family social worker visits).
We followed participants for 6 months to assess their self-reported achievement of behaviors reflecting their discussions about LKT and/or pursuit of LKT (discussions with family; discussions with physicians; initiating recipient evaluation; completing recipient evaluation; identifying a potential living donor).
We assessed outcomes via questionnaire at 1, 3, and 6-month follow up.
Participants receiving Usual Care with their nephrologists (n=44), TALK Education (n=43), and the TALK Social Worker (n=43) were similar at baseline. TALK Study interventions improved participants’ LKT discussion and pursuit behaviors, with the Social Worker leading to greater patient activation (participants’ predicted probability (95% confidence interval) of achieving LKT discussions, evaluations, or donor identification over 6 months in Usual Care, TALK Education, and TALK Social Worker groups: 30% (20%–46%), 42% (33% –54%), and 58% (41% –83%), respectively (p=0.03).
Our population was well educated and mostly insured, potentially limiting generalizability of our findings.
TALK interventions improved discussion and active pursuit of LKT among patients with progressive CKD and may improve their utilization of pre-emptive LKT.
PMCID: PMC3710736  PMID: 23089512
8.  African American and Non-African American Patients’ and Families’ Decision Making About Renal Replacement Therapies 
Qualitative health research  2012;22(7):997-1006.
We conducted focus group meetings of African American and non-African American patients with end-stage renal disease (six groups) and their family members (six groups), stratified by race/ethnicity and treatment. We elicited differences in participants’ experiences with shared decision making about initiating renal replacement therapy (RRT; that is, hemodialysis, peritoneal dialysis, or a kidney transplant). Patients were often very sick when initiating RRT, and had little, if any, time to make a decision about what type of RRT to initiate. They also lacked sufficient information about alternative treatment options prior to initiation. Family members played supportive roles and shared in decision making when possible. Reports were similar for African American and non-African American participants. Our findings suggest that a greater emphasis on the improved engagement of patients and their families in shared decision making about RRT initiation is needed for both ethnic/racial minorities and nonminorities.
PMCID: PMC3927418  PMID: 22645225
African Americans; communication; medical; decision making; illness and disease; chronic; illness and disease; experiences; minorities; nephrology
9.  Trends in anemia management in US hemodialysis patients 2004–2010 
BMC Nephrology  2013;14:264.
There have been major changes in the management of anemia in US hemodialysis patients in recent years. We sought to determine the influence of clinical trial results, safety regulations, and changes in reimbursement policy on practice.
We examined indicators of anemia management among incident and prevalent hemodialysis patients from a medium-sized dialysis provider over three time periods: (1) 2004 to 2006 (2) 2007 to 2009, and (3) 2010. Trends across the three time periods were compared using generalized estimating equations.
Prior to 2007, the median proportion of patients with monthly hemoglobin >12 g/dL for patients on dialysis 0 to 3, 4 to 6 and 7 to 18 months, respectively, was 42%, 55% and 46% declined to 41%, 54%, and 40% after 2007, and declined more sharply in 2010 to 34%, 41%, and 30%. Median weekly Epoeitin alpha doses over the same periods were 18,000, 12,400, and 9,100 units before 2007; remained relatively unchanged from 2007 to 2009; and decreased sharply in the patients 3–6 and 6–18 months on dialysis to 10,200 and 7,800 units, respectively in 2010. Iron doses, serum ferritin, and transferrin saturation levels increased over time with more pronounced increases in 2010.
Modest changes in anemia management occurred between 2007 and 2009, followed by more dramatic changes in 2010. Studies are needed to examine the effects of declining erythropoietin use and hemoglobin levels and increasing intravenous iron use on quality of life, transplantation rates, infection rates and survival.
PMCID: PMC3866613  PMID: 24289058
Anemia; Erythropoietin stimulating agents; Hemodialysis
10.  Patterns in blood pressure medication use in US incident dialysis patients over the first 6 months 
BMC Nephrology  2013;14:249.
Several observational studies have evaluated the effect of a single exposure window with blood pressure (BP) medications on outcomes in incident dialysis patients, but whether BP medication prescription patterns remain stable or a single exposure window design is adequate to evaluate effect on outcomes is unclear.
We described patterns of BP medication prescription over 6 months after dialysis initiation in hemodialysis and peritoneal dialysis patients, stratified by cardiovascular comorbidity, diabetes, and other patient characteristics. The cohort included 13,072 adult patients (12,159 hemodialysis, 913 peritoneal dialysis) who initiated dialysis in Dialysis Clinic, Inc., facilities January 1, 2003-June 30, 2008, and remained on the original modality for at least 6 months. We evaluated monthly patterns in BP medication prescription over 6 months and at 12 and 24 months after initiation.
Prescription patterns varied by dialysis modality over the first 6 months; substantial proportions of patients with prescriptions for beta-blockers, renin angiotensin system agents, and dihydropyridine calcium channel blockers in month 6 no longer had prescriptions for these medications by month 24. Prescription of specific medication classes varied by comorbidity, race/ethnicity, and age, but little by sex. The mean number of medications was 2.5 at month 6 in hemodialysis and peritoneal dialysis cohorts.
This study evaluates BP medication patterns in both hemodialysis and peritoneal dialysis patients over the first 6 months of dialysis. Our findings highlight the challenges of assessing comparative effectiveness of a single BP medication class in dialysis patients. Longitudinal designs should be used to account for changes in BP medication management over time, and designs that incorporate common combinations should be considered.
PMCID: PMC3840675  PMID: 24219348
Blood pressure medication; Dialysis; Medication use patterns
11.  Perceptions and use of the national kidney foundation KDOQI guidelines: a survey of U.S. renal healthcare providers 
BMC Nephrology  2013;14:230.
The National Kidney Foundation (NKF) Kidney Disease Outcomes Quality Initiative (KDOQI) developed guidelines to care for patients with chronic kidney disease (CKD). While these are disseminated through the NKF’s website and publications, the guidelines’ usage remains suboptimal. The KDOQI Educational Committee was formed to identify barriers to guideline implementation, determine provider and patient educational needs and develop tools to improve care of patients with CKD.
An online survey was conducted from May to September 2010 to evaluate renal providers’ familiarity, current use of and attitudes toward the guidelines and tools to implement the guidelines.
Most responders reported using the guidelines often and felt that they could be easily implemented into clinical practice; however, approximately one-half identified at least one barrier. Physicians and physician extenders most commonly cited the lack of evidence supporting KDOQI guidelines while allied health professionals most commonly listed patient non-adherence, unrealistic guideline goals and provider time-constraints. Providers thought that the guidelines included too much detail and identified the lack of a quick resource as a barrier to clinical implementation. Most were unaware of the Clinical Action Plans.
Perceived barriers differed between renal clinicians and allied health professionals; educational and implementation tools tailored for different providers are needed.
PMCID: PMC4016578  PMID: 24152744
KDOQI; Chronic kidney disease; Guidelines; Survey
12.  Predictors of high sensitivity cardiac troponin T in chronic kidney disease patients: a cross-sectional study in the chronic renal insufficiency cohort (CRIC) 
BMC Nephrology  2013;14:229.
Cardiac troponin T is independently associated with cardiovascular events and mortality in patients with chronic kidney disease (CKD). Serum levels of high sensitivity cardiac troponin T (hs-TnT) reflect subclinical myocardial injury in ambulatory patients. We sought to determine the distribution and predictors of hs-TnT in CKD patients without overt cardiovascular disease (CVD).
We studied 2464 participants within the multi-ethnic Chronic Renal Insufficiency Cohort (CRIC) who did not have self-reported CVD. We considered renal and non-renal factors as potential determinants of hs-TnT, including demographics, comorbidities, left ventricular (LV) mass, serologic factors, estimated glomerular filtration rate (eGFR) and albumin to creatinine ratio.
Hs-TnT was detectable in 81% of subjects, and the median (IQR) hs-TnT was 9.4 pg/ml (4.3-18.3). Analysis was performed using Tobit regression, adjusting for renal and non-renal factors. After adjustment, lower eGFR was associated with higher expected hs-TnT; participants with eGFR < 30 ml/min/1.73 m2 had 3-fold higher expected hs-TnT compared to subjects with eGFR > 60. Older age, male gender, black race, LV mass, diabetes and higher blood pressure all had strong, independent associations with higher expected hs-TnT.
Knowledge of the determinants of hs-TnT in this cohort may guide further research on the pathology of heart disease in patients with CKD and help to stratify sub-groups of CKD patients at higher cardiovascular risk.
PMCID: PMC4016297  PMID: 24148285
Troponin T; Chronic kidney disease; Cardiovascular disease
13.  Frailty and falls among adult patients undergoing chronic hemodialysis: a prospective cohort study 
BMC Nephrology  2013;14:224.
Patients undergoing hemodialysis are at high risk of falls, with subsequent complications including fractures, loss of independence, hospitalization, and institutionalization. Factors associated with falls are poorly understood in this population. We hypothesized that insights derived from studies of the elderly might apply to adults of all ages undergoing hemodialysis; we focused on frailty, a phenotype of physiological decline strongly associated with falls in the elderly.
In this prospective, longitudinal study of 95 patients undergoing hemodialysis (1/2009-3/2010), the association of frailty with future falls was explored using adjusted Poisson regression. Frailty was classified using the criteria established by Fried et al., as a combination of five components: shrinking, weakness, exhaustion, low activity, and slowed walking speed.
Over a median 6.7-month period of longitudinal follow-up, 28.3% of study participants (25.9% of those under 65, 29.3% of those 65 and older) experienced a fall. After adjusting for age, sex, race, comorbidity, disability, number of medications, marital status, and education, frailty independently predicted a 3.09-fold (95% CI: 1.38-6.90, P=0.006) higher number of falls. This relationship between frailty and falls did not differ for younger and older adults (P=0.57).
Frailty, a validated construct in the elderly, was a strong and independent predictor of falls in adults undergoing hemodialysis, regardless of age. Our results may aid in identifying frail hemodialysis patients who could be targeted for multidimensional fall prevention strategies.
PMCID: PMC3852906  PMID: 24131569
Hemodialysis; Falls; Frailty
14.  Associations of Multiple Metals with Kidney Outcomes in Lead Workers 
Environmental exposure to multiple metals is common. A number of metals cause nephrotoxicity with acute and/or chronic exposure. However, few epidemiologic studies have examined the impact of metal co-exposure on kidney function. Therefore, we evaluated associations of antimony and thallium with kidney outcomes and assessed the impact of cadmium exposure on those associations in lead workers.
Multiple linear regression was used to examine associations between ln-urine thallium, antimony and cadmium levels with serum creatinine- and cystatin-C-based glomerular filtration measures, and ln-urine N-acetyl-β-D-glucosaminidase (NAG).
In 684 participants, median urine thallium and antimony were 0.39 and 0.36 μg/g creatinine, respectively. After adjustment for lead dose, urine creatinine, and kidney risk factors, higher ln-urine thallium was associated with higher serum creatinine- and cystatin-C-based estimates of glomerular filtration rate (eGFR); associations remained significant after adjustment for antimony and cadmium (regression coefficient for serum creatinine-based eGFR = 5.2 mL/min/1.73 m2; 95% confidence interval = 2.4, 8.0). Antimony associations with kidney outcomes were attenuated by thallium and cadmium adjustment; thallium and antimony associations with NAG were attenuated by cadmium.
Urine thallium levels were significantly associated with both serum creatinine- and cystatin-C-based glomerular filtration measures in a direction opposite that expected with nephrotoxicity. Given similarities to associations recently observed with cadmium, these results suggest that interpretation of urine metal values, at exposure levels currently present in the environment, may be more complex than previously appreciated. These results also support multiple metal analysis approaches to decrease the potential for inaccurate risk conclusions.
PMCID: PMC3542392  PMID: 22843435
antimony; cadmium; creatinine; kidney function; thallium
15.  U.S. Centers for Disease Control and Prevention launches new chronic kidney disease surveillance system website 
BMC Nephrology  2013;14:196.
The burden of chronic kidney disease (CKD) is substantial and is associated with poor health outcomes including increase hospitalizations and premature deaths, as well as considerable health care cost. In recognition of this mounting public health problem, the U.S. Centers for Disease Control and Prevention and their collaborators created a national CKD surveillance system. This commentary introduces the national CKD surveillance system and discusses some of its potential uses.
PMCID: PMC3847207  PMID: 24034342
Chronic kidney disease; Centers for Disease Control and Prevention; Epidemiology; Surveillance; Website
16.  Estimating GFR Among Participants in the Chronic Renal Insufficiency Cohort (CRIC) Study 
Glomerular filtration rate (GFR) is considered the best measure of kidney function, but repeated assessment is not feasible in most research studies.
Study Design
Cross-sectional study of 1,433 participants from the Chronic Renal Insufficiency Cohort (CRIC) Study (i.e., the GFR subcohort) to derive an internal GFR estimating equation using a split sample approach.
Setting & Participants
Adults from 7 US metropolitan areas with mild to moderate chronic kidney disease; 48% had diabetes and 37% were black.
Index Test
CRIC GFR estimating equation
Reference Test or Outcome
Urinary 125I-iothalamate clearance testing (measured GFR)
Other Measurements
Laboratory measures including serum creatinine and cystatin C, and anthropometrics
In the validation dataset, the model that included serum creatinine, serum cystatin C, age, gender, and race was the most parsimonious and similarly predictive of mGFR compared to a model additionally including bioelectrical impedance analysis phase angle, CRIC clinical center, and 24-hour urinary creatinine excretion. Specifically, the root mean square errors for the separate model were 0.207 vs. 0.202, respectively. The performance of the CRIC GFR estimating equation was most accurate among the subgroups of younger participants, men, non-blacks, non-Hispanics, those without diabetes, those with body mass index <30 kg/m2, those with higher 24-hour urine creatinine excretion, those with lower levels of high-sensitivity C-reactive protein, and those with higher mGFR.
Urinary clearance of 125I-iothalamate is an imperfect measure of true GFR; cystatin C is not standardized to certified reference material; lack of external validation; small sample sizes limit analyses of subgroup-specific predictors.
The CRIC GFR estimating equation predicts measured GFR accurately in the CRIC cohort using serum creatinine and cystatin C, age, gender, and race. Its performance was best among younger and healthier participants.
PMCID: PMC3565578  PMID: 22658574
glomerular filtration rate (GFR); kidney function; GFR estimation
17.  Retinopathy and Chronic Kidney Disease in the Chronic Renal Insufficiency Cohort Study (CRIC) 
Archives of ophthalmology  2012;130(9):1136-1144.
Retinal vascular and anatomic abnormalities caused by diabetes, hypertension, and other conditions can be observed directly in the ocular fundus and may reflect severity of chronic renal insufficiency. The purpose of this study was to investigate the association between retinopathy and chronic kidney disease (CKD).
In this observational, cross-sectional study, 2605 participants of the Chronic Renal Insufficiency Cohort (CRIC) study, a multi-center study of CKD, were offered participation. Non-mydriatic fundus photographs of the disc and macula in both eyes were obtained in 1936 of these subjects.
Photographs were reviewed in a masked fashion at a central photograph reading center using standard protocols. Presence and severity of retinopathy (diabetic, hypertensive or other) and vessel diameter caliber were assessed by trained graders and a retinal specialist using protocols developed for large epidemiologic studies. Kidney function measurements and information on traditional and non-traditional risk factors for decreased kidney function were obtained from the CRIC study.
Greater severity of retinopathy was associated with lower estimated glomerular filtration rate (eGFR) after adjustment for traditional and non-traditional risk factors. Presence of vascular abnormalities usually associated with hypertension was also associated with lower eGFR. We found no strong direct relationship between eGFR and average arteriolar or venular calibers.
Our findings show a strong association between severity of retinopathy and its features and level of kidney function after adjustment for traditional and non-traditional risk factors for CKD, suggesting that retinovascular pathology reflects renal disease.
PMCID: PMC3719171  PMID: 22965589
Retinopathy; Retinal Vascular Diameter; Chronic Kidney Disease
18.  Access to Health Care Among Adults Evaluated for CKD: Findings From the Kidney Early Evaluation Program (KEEP) 
Data are scant regarding access to health care in patients with chronic kidney disease (CKD). We performed descriptive analyses using data from the National Kidney Foundation’s Kidney Early Evaluation Program (KEEP), a nationwide health screening program for adults at high risk of CKD.
From 2000–2010, a total of 122,502 adults without end-stage renal disease completed KEEP screenings; 27,927 (22.8%) met criteria for CKD (10,082, stages 1–2; 16,684, stage 3; and 1,161, stages 4–5). CKD awareness, self-rated health status, frequency of physician visits, difficulty obtaining medical care, types of caregivers, insurance status, and medication coverage and estimated costs were assessed.
Participants with CKD were more likely to report fair/poor health status than those without CKD. Health care utilization increased at later CKD stages; ~95% of participants at stages 3–5 had visited a physician during the preceding year compared with 83.7% of participants without CKD. More Hispanic and African American than white participants at all CKD stages reported not having a physician. Approximately 40% of participants younger than 65 years reported fair/poor health status at stages 4–5 compared with ~30% who were 65 years and older. Younger participants at all stages were more likely to report extreme or somewhat/moderate difficulty obtaining medical care. Comorbid conditions (diabetes, hypertension, and prior cardiovascular events) were associated with increased utilization of care. Utilization of nephrology care was poor at all CKD stages; <6% of participants at stage 3 and <30% at stages 4–5 reported ever seeing a nephrologist.
Lack of health insurance and perceived difficulty obtaining medical care with lower health care utilization, both of which are consistent with inadequate access to health care, are more likely for KEEP participants who are younger than 65 years, nonwhite, and without previously diagnosed comorbid conditions. Nephrology care is infrequent in elderly participants with advanced CKD who are nonwhite, have comorbid disease, and have high-risk states for cardiovascular disease.
PMCID: PMC3694584  PMID: 22339901
Chronic kidney disease; health care access; health insurance; medication payment; socioeconomic status; educational status
19.  Selecting renal replacement therapies: what do African American and non-African American patients and their families think others should know? A mixed methods study 
BMC Nephrology  2013;14:9.
Little is known regarding the types of information African American and non-African American patients with chronic kidney disease (CKD) and their families need to inform renal replacement therapy (RRT) decisions.
In 20 structured group interviews, we elicited views of African American and non-African American patients with CKD and their families about factors that should be addressed in educational materials informing patients’ RRT selection decisions. We asked participants to select factors from a list and obtained their open-ended feedback.
Ten groups of patients (5 African American, 5 non-African American; total 68 individuals) and ten groups of family members (5 African American, 5 non-African American; total 62 individuals) participated. Patients and families had a range (none to extensive) of experiences with various RRTs. Patients identified morbidity or mortality, autonomy, treatment delivery, and symptoms as important factors to address. Family members identified similar factors but also cited the effects of RRT decisions on patients’ psychological well-being and finances. Views of African American and non-African American participants were largely similar.
Educational resources addressing the influence of RRT selection on patients’ morbidity and mortality, autonomy, treatment delivery, and symptoms could help patients and their families select RRT options closely aligned with their values. Including information about the influence of RRT selection on patients’ personal relationships and finances could enhance resources’ cultural relevance for African Americans.
PMCID: PMC3565884  PMID: 23317336
Decision-making; Renal replacement therapy; Family members; African American
20.  Comparative effectiveness studies to improve clinical outcomes in end stage renal disease: the DEcIDE patient outcomes in end stage renal disease study 
BMC Nephrology  2012;13:167.
Evidence is lacking to inform providers’ and patients’ decisions about many common treatment strategies for patients with end stage renal disease (ESRD).
The DEcIDE Patient Outcomes in ESRD Study is funded by the United States (US) Agency for Health Care Research and Quality to study the comparative effectiveness of: 1) antihypertensive therapies, 2) early versus later initiation of dialysis, and 3) intravenous iron therapies on clinical outcomes in patients with ESRD. Ongoing studies utilize four existing, nationally representative cohorts of patients with ESRD, including (1) the Choices for Healthy Outcomes in Caring for ESRD study (1041 incident dialysis patients recruited from October 1995 to June 1999 with complete outcome ascertainment through 2009), (2) the Dialysis Clinic Inc (45,124 incident dialysis patients initiating and receiving their care from 2003–2010 with complete outcome ascertainment through 2010), (3) the United States Renal Data System (333,308 incident dialysis patients from 2006–2009 with complete outcome ascertainment through 2010), and (4) the Cleveland Clinic Foundation Chronic Kidney Disease Registry (53,399 patients with chronic kidney disease with outcome ascertainment from 2005 through 2009). We ascertain patient reported outcomes (i.e., health-related quality of life), morbidity, and mortality using clinical and administrative data, and data obtained from national death indices. We use advanced statistical methods (e.g., propensity scoring and marginal structural modeling) to account for potential biases of our study designs. All data are de-identified for analyses. The conduct of studies and dissemination of findings are guided by input from Stakeholders in the ESRD community.
The DEcIDE Patient Outcomes in ESRD Study will provide needed evidence regarding the effectiveness of common treatments employed for dialysis patients. Carefully planned dissemination strategies to the ESRD community will enhance studies’ impact on clinical care and patients’ outcomes.
PMCID: PMC3554422  PMID: 23217181
21.  Differences in urine cadmium associations with kidney outcomes based on serum creatinine and cystatin C 
Environmental research  2011;111(8):1236-1242.
Cadmium is a well known nephrotoxicant; chronic exposure increases risk for chronic kidney disease. Recently, however, associations between urine cadmium and higher creatinine-based estimated glomerular filtration rate (eGFR) have been reported. Analyses utilizing alternate biomarkers of kidney function allow evaluation of potential mechanisms for these observations. We compared associations of urine cadmium with kidney function measures based on serum cystatin C to those with serum creatinine in 712 lead workers. Mean (standard deviation) molybdenum-corrected urine cadmium, Modification of Diet in Renal Disease (MDRD) eGFR and multi-variable cystatin C eGFR were 1.02 (0.65) μg/g creatinine, and 97.4 (19.2) and 112.0 (17.7) mL/min/1.73 m2, respectively. The eGFR measures were moderately correlated (rs = 0.5; p less than 0.001). After adjustment, ln(urine cadmium) was not associated with serum cystatin-C-based measures. However, higher ln(urine cadmium) was associated with higher creatinine-based eGFRs including the MDRD and an equation incorporating serum cystatin C and creatinine (beta-coefficient = 4.1 ml/min/1.73 m2; 95% confidence interval =1.6, 6.6). Urine creatinine was associated with serum creatinine-based but not cystatin-C-based eGFRs. These results support a biomarker-specific, rather than a kidney function, effect underlying the associations observed between higher urine cadmium and creatinine-based kidney function measures. Given the routine use of serum and urine creatinine in kidney and biomarker research, additional research to elucidate the mechanism(s) for these associations is essential.
PMCID: PMC3210933  PMID: 21871619
cadmium; cystatin C; kidney function; serum creatinine; urine creatinine
22.  The providing resources to enhance African American patients’ readiness to make decisions about kidney disease (PREPARED) study: protocol of a randomized controlled trial 
BMC Nephrology  2012;13:135.
Living related kidney transplantation (LRT) is underutilized, particularly among African Americans. The effectiveness of informational and financial interventions to enhance informed decision-making among African Americans with end stage renal disease (ESRD) and improve rates of LRT is unknown.
We report the protocol of the Providing Resources to Enhance African American Patients’ Readiness to Make Decisions about Kidney Disease (PREPARED) Study, a two-phase study utilizing qualitative and quantitative research methods to design and test the effectiveness of informational (focused on shared decision-making) and financial interventions to overcome barriers to pursuit of LRT among African American patients and their families. Study Phase I involved the evidence-based development of informational materials as well as a financial intervention to enhance African American patients’ and families’ proficiency in shared decision-making regarding LRT. In Study Phase 2, we are currently conducting a randomized controlled trial in which patients with new-onset ESRD receive 1) usual dialysis care by their nephrologists, 2) the informational intervention (educational video and handbook), or 3) the informational intervention in addition to the option of participating in a live kidney donor financial assistance program. The primary outcome of the randomized controlled trial will include patients’ self-reported rates of consideration of LRT (including family discussions of LRT, patient-physician discussions of LRT, and identification of a LRT donor).
Results from the PREPARED study will provide needed evidence on ways to enhance the decision to pursue LRT among African American patients with ESRD.
Trial registration NCT01439516
PMCID: PMC3489555  PMID: 23057616
Shared decision-making; Live kidney transplantation; Live kidney donation; Chronic kidney disease; End stage renal disease
23.  Associations of blood lead with estimated glomerular filtration rate using MDRD, CKD-EPI and serum cystatin C-based equations 
Nephrology Dialysis Transplantation  2011;26(9):2786-2792.
Background. Low-level lead exposure is widespread and has been implicated as a chronic kidney disease (CKD) risk factor. However, studies evaluating associations of lead dose with newer, potentially more accurate, estimates of kidney function, in participants with a wide range of glomerular filtration rates (GFRs), are scarce.
Methods. We compared associations of blood lead and estimated glomerular filtration rate (eGFR) using the Modification of Diet in Renal Disease (MDRD), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) and cystatin C single variable, multivariable and combined creatinine/cystatin C equations in 3941 adults who participated in the 1999–2002 National Health and Nutrition Examination Survey cystatin C subsample.
Results. Geometric mean blood lead was 1.7 μg/dL. After multivariable adjustment, differences [95% confidence interval (CI)] in mean eGFR for a doubling of blood lead were −1.9 (−3.2, −0.7), −1.7 (−3.0, −0.5) and −1.4 (−2.3, −0.5) mL/min/1.73 m2, using the cystatin C single variable, multivariable and combined creatinine/cystatin C equations, respectively, reflecting lower eGFR with increased blood lead. The corresponding differences (95% CI) were −0.9 (−1.9, 0.02) and −0.9 (−1.8, 0.01) using the creatinine-based MDRD and CKD-EPI equations, respectively. In participants aged ≥60 years, differences in mean eGFR ranged from −3.0 to −4.5 mL/min/1.73 m2, and odds of reduced eGFR (<60 mL/min/1.73 m2) were increased for all estimates of GFR.
Conclusions. These results support the inclusion of cystatin C-based eGFR in future lead research and provide additional evidence for environmental lead exposure as a CKD risk factor.
PMCID: PMC3203408  PMID: 21248295
blood lead; kidney function; lead exposure; NHANES
24.  Soluble P-Selectin Levels Are Associated with Cardiovascular Mortality and Sudden Cardiac Death in Male Dialysis Patients 
American Journal of Nephrology  2011;33(3):224-230.
P-selectin is released by activated platelets and endothelium contributing to inflammation and thrombosis. We evaluated the association between soluble P-selectin and atherosclerotic cardiovascular disease (ASCVD) in dialysis patients.
We measured soluble P-selectin in serum from 824 incident dialysis patients. Using Cox proportional hazards models, we modeled the association of P-selectin levels with ASCVD events, cardiovascular mortality and sudden cardiac death.
After adjustment for demographics, comorbidity and traditional cardiovascular risk factors, higher P-selectin levels were associated with increased risk of ASCVD and cardiovascular mortality among males (p = 0.02 and p = 0.01, respectively), but not females (p = 0.52 and p = 0.31, respectively; p interaction = 0.003), over a median of 38.2 months. Higher P-selectin was associated with a greater risk of sudden cardiac death among males (p = 0.05). The associations between increasing P-selectin and cardiovascular mortality as well as sudden cardiac death in males persisted after adjustment for C-reactive protein, interleukin-6, serum albumin and platelet count (p = 0.01 and p = 0.03, respectively). The risk for sudden cardiac death was more than 3 times greater for males in the highest tertile of soluble P-selectin compared with the lowest tertile after adjustment (HR: 3.19; 95% CI: 1.18 – 8.62; p = 0.02).
P-selectin is associated with ASCVD, cardiovascular mortality and sudden cardiac death among male dialysis patients.
PMCID: PMC3064942  PMID: 21346329
Cardiovascular disease; Dialysis; End-stage renal disease; Inflammation; Sudden cardiac death; P-selectin
25.  Association of Residual Urine Output with Mortality, Quality of Life, and Inflammation in Incident Hemodialysis Patients: The CHOICE (Choices for Healthy Outcomes in Caring for End-Stage Renal Disease) Study 
Residual kidney function (RKF) is associated with improved survival in peritoneal dialysis patients but its role in hemodialysis patients is less well known. Urine output may provide an estimate of RKF. The aim of our study was to determine the association of urine output with mortality, quality of life (QOL) and inflammation in incident hemodialysis patients.
Study Design
Nationally representative prospective cohort study
Setting & Participants
734 incident hemodialysis participants treated in 81 clinics; enrollment, 1995-1998, follow-up until December 2004.
Urine output, defined as producing at least 250 mL (1 cup) of urine daily, ascertained by questionnaires at baseline and year 1.
Outcomes & Measurements
Primary outcomes were all-cause and cardiovascular (CVD) mortality, analyzed using Cox regression adjusted for demographic, clinical and treatment characteristics. Secondary outcomes were QOL, inflammation (CRP and interleukin-6 [IL-6] levels) and erythropoietin (EPO) requirements.
617/734 (84%) participants reported urine output at baseline and 163/579 (28%) at year 1. Baseline urine output was not associated with survival. Urine output at year 1, indicating preserved RKF, was independently associated with lower all-cause mortality (Hazard Ratio [HR], 0.70; 95% Confidence Interval [CI], 0.52-0.93; p=0.02) and a trend towards lower CVD mortality (HR, 0.69; 95% CI, 0.45-1.05; p=0.09). Participants with urine output at baseline reported better QOL and had lower CRP (p=0.02) and IL-6 (p=0.03) levels. Importantly, EPO dose was 12,000 units/week lower in those with urine output at year 1 compared with those without (p=0.001).
Urine volume was measured in only a subset of patients (42%) but was in agreement with self-report (p<0.001).
RKF in hemodialysis patients is associated with better survival and QOL, lower inflammation and significantly less EPO use. RKF should be monitored routinely in hemodialysis patients. Development of methods to assess and preserve RKF is important and may improve dialysis care.
PMCID: PMC2910835  PMID: 20605303
End-stage Renal Disease; Hemodialysis; Residual Kidney Function; Mortality; Quality of Life; Inflammation

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