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1.  Validation of CKD and Related Conditions in Existing Datasets: A Systematic Review 
Accurate classification of individuals with kidney disease is vital to research and public health efforts aimed at improving health outcomes. Our objective was to identify and synthesize published literature evaluating the accuracy of existing data sources related to kidney disease.
Study design
A systematic review of studies seeking to validate the accuracy of the underlying data relevant to kidney disease.
Setting & Population
U.S.-based and international studies covering a wide range of both outpatient and inpatient study populations.
Selection Criteria for Studies
Any English-language study investigating the prevalence or etiology of kidney disease, the existence of co-morbid conditions, or the cause of death in those with CKD. All definitions and stages of CKD, including end-stage renal disease (ESRD), were accepted.
Index Tests
Presence of a kidney disease-related variable in existing datasets, including administrative datasets and disease registries.
Reference Tests
Presence of a kidney disease-related variable defined by laboratory criteria or medical record review.
Thirty studies were identified. Most studies investigated the accuracy of kidney disease reporting, comparing coded renal disease to that defined by estimated glomerular filtration rate (eGFR). Sensitivity of coded renal disease varied widely (0.08–0.83). Specificity was higher, with all studies reporting values of ≥0.90. The studies evaluating the etiology of CKD, comorbidities, and the cause of death in CKD all used ESRD or transplant populations exclusively, and accuracy was highly variable when compared to ESRD registry data.
Only English-language studies were evaluated.
Given the heterogeneous results of validation studies, a variety of attributes of existing data sources, including the accuracy of individual data items within these sources, should be carefully considered prior to use in research, quality improvement and public health efforts.
PMCID: PMC2978782  PMID: 20692079
2.  Effect of Food Insecurity on Chronic Kidney Disease in Lower Income Americans 
American journal of nephrology  2014;39(1):27-35.
The relation of food insecurity (inability to acquire nutritionally adequate and safe foods) and chronic kidney disease (CKD) is unknown. We examined whether food insecurity is associated with prevalent CKD among lower income individuals in both the general U.S. adult population and an urban population.
We conducted cross-sectional analyses of lower income participants of the National Health and Nutrition Examination Survey (NHANES) 2003–2008 (n=9,126); and the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) study (n=1,239). Food insecurity was defined based on questionnaires and CKD was defined by reduced estimated glomerular filtration rate or albuminuria; adjustment was performed with multivariable logistic regression.
In NHANES, the age-adjusted prevalence of CKD was 20.3%, 17.6% and 15.7% for the high, marginal and no food insecurity groups, respectively. Analyses adjusting for sociodemographics and smoking status revealed high food insecurity to be associated with greater odds of CKD only among participants with either diabetes [odds ratio (OR) 1.67, 95% confidence interval (CI) 1.14–2.45 comparing high to no food insecurity group] or hypertension (OR 1.37, 95% CI 1.03–1.82). In HANDLS, the age-adjusted CKD prevalence was 5.9% and 4.6% for those with and without food insecurity, respectively (P=0.33). Food insecurity was associated with a trend towards greater odds of CKD (OR 1.46, 95% CI 0.98–2.18) with no evidence of effect modification across diabetes, hypertension or obesity subgroups.
Food insecurity may contribute to disparities in kidney disease, especially among persons with diabetes or hypertension, and is worthy of further study.
PMCID: PMC3952065  PMID: 24434743
renal; socioeconomic status; disparity; nutrition
3.  Population-Based Screening for CKD 
Organizations both in the U.S. and globally have advocated for screening for chronic kidney disease with a urine test for proteinuria followed by subsequent testing with creatinine-based, eGFR determinations. Screening for a disease, such as chronic kidney disease, can have value, but a decision to screen is not a trivial decision. Criteria must be met in order to balance the aggregate benefits with the risks and costs of a screening test. We discuss how screening for chronic kidney disease meets many of these criteria, but also how the populations to whom it is applied must be targeted and the strategies for testing must be clearly defined.
PMCID: PMC2681232  PMID: 19231763
4.  Public Health Surveillance of CKD: Principles, Steps, and Challenges 
Population-based surveillance of disease has become an important component of addressing common chronic diseases such as hypertension and diabetes. Such systems guide screening, prevention and treatment resources. Development of a chronic kidney disease (CKD) surveillance system for the United States that focuses on early stages of CKD is an important activity that could help stem the rising number of end-stage renal disease cases and CKD-related morbidity and mortality in the United States. It could also help in the evaluation of interventional programs that are currently being developed or are already in place. Such a surveillance system should address the burden of CKD, awareness of CKD, CKD risk factors, CKD consequences, process and quality of care in CKD and health system capacity for CKD; it should also allow for estimations of the burden of CKD by age, sex, race/ethnicity, socioeconomic strata, geographic groups and clinical subgroups. We describe the key components of a surveillance system for CKD, steps in development of such a system and challenges that will need to be addressed. Information necessary for surveillance of CKD is evolving. At this juncture, collecting, integrating, analyzing, and interpreting information on CKD for surveillance using a systematic, comprehensive and feasible approach will be instrumental in prevention and health promotion efforts for this chronic disease.
PMCID: PMC2680244  PMID: 19231759
5.  Low income, community poverty and risk of end stage renal disease 
BMC Nephrology  2014;15(1):192.
The risk of end stage renal disease (ESRD) is increased among individuals with low income and in low income communities. However, few studies have examined the relation of both individual and community socioeconomic status (SES) with incident ESRD.
Among 23,314 U.S. adults in the population-based Reasons for Geographic and Racial Differences in Stroke study, we assessed participant differences across geospatially-linked categories of county poverty [outlier poverty, extremely high poverty, very high poverty, high poverty, neither (reference), high affluence and outlier affluence]. Multivariable Cox proportional hazards models were used to examine associations of annual household income and geospatially-linked county poverty measures with incident ESRD, while accounting for death as a competing event using the Fine and Gray method.
There were 158 ESRD cases during follow-up. Incident ESRD rates were 178.8 per 100,000 person-years (105 py) in high poverty outlier counties and were 76.3 /105 py in affluent outlier counties, p trend = 0.06. In unadjusted competing risk models, persons residing in high poverty outlier counties had higher incidence of ESRD (which was not statistically significant) when compared to those persons residing in counties with neither high poverty nor affluence [hazard ratio (HR) 1.54, 95% Confidence Interval (CI) 0.75-3.20]. This association was markedly attenuated following adjustment for socio-demographic factors (age, sex, race, education, and income); HR 0.96, 95% CI 0.46-2.00. However, in the same adjusted model, income was independently associated with risk of ESRD [HR 3.75, 95% CI 1.62-8.64, comparing the < $20,000 income group to the > $75,000 group]. There were no statistically significant associations of county measures of poverty with incident ESRD, and no evidence of effect modification.
In contrast to annual family income, geospatially-linked measures of county poverty have little relation with risk of ESRD. Efforts to mitigate socioeconomic disparities in kidney disease may be best appropriated at the individual level.
PMCID: PMC4269852  PMID: 25471628
ESRD; Chronic kidney disease; Socioeconomic status; Disparity; Geospatial
6.  Phosphate Levels and Blood Pressure in Incident Hemodialysis Patients: A Longitudinal Study 
An elevated serum phosphate level in hemodialysis patients has been associated with mineral deposition in blood vessels. We studied a possible physiologic consequence of hyperphosphatemia by examining the relation between serum phosphate levels and blood pressure in 707 incident hemodialysis patients from 75 clinics who were enrolled in a prospective cohort study. We conducted cross-sectional and longitudinal multiple linear regression analyses, adjusting for demographics, medical history and laboratory factors. In cross-sectional analyses at baseline, elevated serum phosphate was associated with higher pre-dialysis systolic blood pressure (SBP) and pulse pressure (PP) at the start of dialysis; each 1 mg/dL higher phosphate level was associated with 1.77 mmHg higher SBP. In multivariable adjusted longitudinal analyses, for each 1 mg/dL higher serum phosphate at baseline, SBP was higher at: 3 months, 1.36 mmHg (p=0.005); 6 months, 1.13 mmHg (p=0.035); 12 months, 1.65 mmHg (p=0.008); 18 months, 1.44 mmHg (p=0.031); and 27 months, 2.54 mmHg (p=0.002); and PP was higher at: 3 months, 0.80 mmHg (p=0.027); 6 months, 0.91 mmHg (p=0.022); 12 months, 1.45 mmHg (p<0.001); 18 months, 1.06 mmHg (p=0.026); and 27 months, 1.37 mmHg (p=0.020). This study suggests that serum phosphate level is strongly and independently associated with blood pressure in hemodialysis patients. The effect of rigorous control of serum phosphate levels on arterial stiffness and blood pressure should be studied in clinical trials.
PMCID: PMC2529257  PMID: 18565483
phosphate; blood pressure; hemodialysis
7.  Patient Awareness in Chronic Kidney Disease: Trends and Predictors 
Archives of internal medicine  2008;168(20):2268-2275.
The impact of recent guidelines for early detection and prevention of chronic kidney disease (CKD) on patient awareness of disease and factors that might be associated with awareness have not been well-described.
Awareness rates were assessed in 2992 adults (≥20 years) with CKD stages 1-4 from a nationally representative, cross-sectional survey (National Health and Nutrition Examination Survey 1999-2004). Awareness of CKD was defined by an answer of yes to: “Have you ever been told you have weak or failing kidneys?” Potential predictors of awareness included demographic, access to care, clinical, and lifestyle factors, which were assessed by standardized interviewer-administered questionnaires and physical exams. We examined independent associations of patient characteristics with awareness in those with CKD stage 3 (N=1314) over 6 years using multivariable logistic regression.
Awareness improved over time in stage 3 only [4.7% (95% CI, 2.6-8.5%), 8.9% (7.1-11.2%), and 9.2% (6.1-13.8%) for 1999-2000, 2001-2002, and 2003-2004, respectively; P = 0.037, adjusted for age, sex, race]. Having proteinuria [OR=3.04 (1.62-5.70)], diabetes [OR=2.19 (1.03-4.64)], and hypertension [OR=2.92 (1.57-5.42)] and being male [OR=2.06 (1.15-3.69)] were all statistically significantly associated with greater awareness among persons with CKD stage 3 after adjustment. CKD awareness increased almost 2-fold for CKD stage 3 over recent years but remains quite low. Persons with risk factors for CKD (proteinuria, diabetes, hypertension, male sex) were more likely to be aware of their stage 3 disease.
Renewed and innovative efforts should be made to increase CKD awareness among patients and providers.
PMCID: PMC2652122  PMID: 19001205
8.  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
9.  Agreement of self-reported comorbid conditions with medical and physician reports varied by disease among End-Stage Renal Disease patients 
Journal of clinical epidemiology  2006;60(6):634-642.
To compare self-report of eight diseases with review of medical records and physician reports.
Study Design and Setting:
In a cohort of 965 incident end-stage renal disease (ESRD) patients (CHOICE study), data on existing medical conditions were obtained from medical record abstraction, physician report (CMS Form 2728), and self-report in a baseline questionnaire. We evaluated agreement with kappa statistics and sensitivity of self-report. Regression models were used to examine characteristics associated with agreement.
The results showed excellent or substantial agreement between self-report and the medical record for diabetes (Kappa statistic (k)=0.93) and coronary artery intervention (k=0.79) and poor agreement for chronic obstructive pulmonary disease (k=0.20). Physician-reported prevalence for all diseases was equal or lower than that by self-report. Male patients were more likely to inaccurately report hypertension. Compared to White patients, African American patients were more likely to inaccurately report cardiovascular diseases.
In ESRD patients, self-report agreement with the medical record varies with the specific disease. Awareness of diseases of the cardiovascular system appears to be low. African American and male ESRD patients are at risk of low awareness of disease and educational interventions are needed in this high-risk population.
PMCID: PMC1991281  PMID: 17493523
Validity; Agreement; Self-report; Kidney; End-Stage renal disease; Medical records; Comorbid
10.  Measuring and Explaining Racial and Ethnic Differences in Willingness to Donate Live Kidneys in the United States 
Clinical transplantation  2013;27(5):673-683.
Reasons for US racial-ethnic minority ESRD patients' reported difficulties identifying live kidney donors are poorly understood.
We conducted a national study to develop scales measuring willingness to donate live kidneys among US adults (scores ranged from 0 (not willing) to 10 (extremely willing)), and we tested whether racial-ethnic differences exist in willingness to donate. We also examined whether clinical, sociodemographic, and attitudinal factors mediated potential racial-ethnic differences in willingness.
Among 845 participants, the majority were extremely willing to donate to relatives (77%) while fewer than half were extremely willing to donate to non-relatives (18%). In multivariable linear regression analyses, willingness to donate varied by race-ethnicity and recipient relationship to the donor. African Americans were less willing to donate to relatives than Whites (β: −0.48; 95% CI: −0.94 to −0.17; p=0.04), but these differences were eliminated after accounting for socioeconomic factors, medical trust, and concerns about burial after death. There were no differences in willingness to donate between Hispanics and Whites.
African Americans' burial concerns, medical trust, and socioeconomic factors explained differences in their willingness to donate to relatives, suggesting efforts to address these barriers may enhance rates of live kidney donation in this group.
PMCID: PMC3795987  PMID: 23902226
live donor kidney transplantation; live kidney donation; minority donation; racial-ethnic disparities; willingness to donate live kidneys
11.  Dietary acid load and chronic kidney disease among adults in the United States 
BMC Nephrology  2014;15:137.
Diet can markedly affect acid-base status and it significantly influences chronic kidney disease (CKD) and its progression. The relationship of dietary acid load (DAL) and CKD has not been assessed on a population level. We examined the association of estimated net acid excretion (NAEes) with CKD; and socio-demographic and clinical correlates of NAEes.
Among 12,293 U.S. adult participants aged >20 years in the National Health and Nutrition Examination Survey 1999–2004, we assessed dietary acid by estimating NAEes from nutrient intake and body surface area; kidney damage by albuminuria; and kidney dysfunction by eGFR < 60 ml/min/1.73m2 using the MDRD equation. We tested the association of NAEes with participant characteristics using median regression; while for albuminuria, eGFR, and stages of CKD we used logistic regression.
Median regression results (β per quintile) indicated that adults aged 40–60 years (β [95% CI] = 3.1 [0.3–5.8]), poverty (β [95% CI] = 7.1 [4.01–10.22]), black race (β [95% CI] = 13.8 [10.8–16.8]), and male sex (β [95% CI] = 3.0 [0.7- 5.2]) were significantly associated with an increasing level of NAEes. Higher levels of NAEes compared with lower levels were associated with greater odds of albuminuria (OR [95% CI] = 1.57 [1.20–2.05]). We observed a trend toward greater NAEes being associated with higher risk of low eGFR, which persisted after adjustment for confounders.
Higher NAEes is associated with albuminuria and low eGFR, and socio-demographic risk factors for CKD are associated with higher levels of NAEes. DAL may be an important target for future interventions in populations at high risk for CKD.
PMCID: PMC4151375  PMID: 25151260
Acidosis; Albuminuria; Chronic kidney disease; NHANES (National Health and Nutrition Examination Survey); Nutrition
12.  Assessment of printed patient-educational materials for chronic kidney disease 
American journal of nephrology  2013;38(3):184-194.
Awareness of chronic kidney disease (CKD) is suboptimal among patients with CKD, perhaps due to poor readability of patient education materials (PEMs). We reviewed the suitability and readability of common PEMs that focused on 5 content areas: basics of CKD, risk factors for CKD development, risk factors for CKD progression, complications of CKD and self-management strategies to improve kidney health.
Three reviewers (nephrologist, primary care physician, patient) used the Suitability Assessment of Materials to rate PEMs on message content/stimulation of learning, typography, visuals and layout and determined literacy level. Mean ratings were calculated for each PEM by content area and overall (Superior=70–100; Adequate=40–69; Inadequate=<40). Linear regression was used to determine the impact of literacy level on mean rating.
We reviewed 69 PEMs from 19 organizations, divided into 113 content area sections. Most (79%) PEM sections were “Adequate” (mean rating, 58.3%). Inclusion of patient-centered content and opportunities for patient interaction were associated with “Superior” ratings. Mean ratings (SD) were similar across content areas: basics of CKD, 58.9% [9.1]; risk factors for CKD development, 57.0% [12.3]; risk factors for CKD progression, 58.5% [12.0]; CKD complications, 62.3% [15.7] and self-management strategies, 62.2% [12.3]. ≤ 6th grade literacy level (vs >6th grade) was associated with an 11.7 point higher mean rating.
Most PEMs for kidney disease were adequate. Outstanding PEMs shared characteristics of patient centeredness, a low literacy level, and patient interaction. Providers should be aware of strengths and limitations of PEMs when educating their patients about CKD.
PMCID: PMC3804301  PMID: 23970127
chronic kidney disease; health literacy; patient education materials
13.  Willingness of the United States general public to participate in kidney paired donation 
Clinical transplantation  2012;26(5):714-721.
Availability of kidney paired donation (KPD) is increasing in the United States, and a national system through UNOS is forthcoming. However, little is known about attitudes toward KPD among the general public, from which donors (particularly non-directed) are drawn.
In a national study, we assessed the public's attitudes regarding participation in KPD.
Among 845 randomly selected participants, 85.2% of respondents were either “extremely willing” or “very willing” to participate in KPD. Experiences with the medical or organ transplant systems, such as undergoing surgery, having a primary medical provider, a living will, a friend who donated or received an organ, and considering donation after death, were associated with increased willingness. However, increased age, male sex, African American race, Hispanic ethnicity, distrust of the medical system, and not understanding organ allocation were associated with less willingness.
We identify strong support for KPD but some important potential barriers to participation which should be considered as KPD programs are implemented.
PMCID: PMC4067490  PMID: 22404601
kidney exchange; kidney transplantation; public attitudes
14.  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
15.  Vitamin D–Binding Protein and Vitamin D Status of Black Americans and White Americans 
The New England journal of medicine  2013;369(21):1991-2000.
Low levels of total 25-hydroxyvitamin D are common among black Americans. Vitamin D–binding protein has not been considered in the assessment of vitamin D deficiency.
In the Healthy Aging in Neighborhoods of Diversity across the Life Span cohort of blacks and whites (2085 participants), we measured levels of total 25-hydroxyvitamin D, vitamin D–binding protein, and parathyroid hormone as well as bone mineral density (BMD). We genotyped study participants for two common polymorphisms in the vitamin D–binding protein gene (rs7041 and rs4588). We estimated levels of bioavailable 25-hydroxyvitamin D in homozygous participants.
Mean (±SE) levels of both total 25-hydroxyvitamin D and vitamin D–binding protein were lower in blacks than in whites (total 25-hydroxyvitamin D, 15.6±0.2 ng per milliliter vs. 25.8±0.4 ng per milliliter, P<0.001; vitamin D–binding protein, 168±3 μg per milliliter vs. 337±5 μg per milliliter, P<0.001). Genetic polymorphisms independently appeared to explain 79.4% and 9.9% of the variation in levels of vitamin D–binding protein and total 25-hydroxyvitamin D, respectively. BMD was higher in blacks than in whites (1.05±0.01 g per square centimeter vs. 0.94±0.01 g per square centimeter, P<0.001). Levels of parathyroid hormone increased with decreasing levels of total or bioavailable 25-hydroxyvitamin D (P<0.001 for both relationships), yet within each quintile of parathyroid hormone concentration, blacks had significantly lower levels of total 25-hydroxyvitamin D than whites. Among homozygous participants, blacks and whites had similar levels of bioavailable 25-hydroxy vitamin D overall (2.9±0.1 ng per milliliter and 3.1±0.1 ng per milliliter, respectively; P = 0.71) and within quintiles of parathyroid hormone concentration.
Community-dwelling black Americans, as compared with whites, had low levels of total 25-hydroxyvitamin D and vitamin D–binding protein, resulting in similar concentrations of estimated bioavailable 25-hydroxyvitamin D. Racial differences in the prevalence of common genetic polymorphisms provide a likely explanation for this observation. (Funded by the National Institute on Aging and others.)
PMCID: PMC4030388  PMID: 24256378
16.  Americans’ Use of Dietary Supplements That Are Potentially Harmful in CKD 
The prevalence in the United States of dietary supplement use that may be harmful to those with chronic kidney disease (CKD) is unknown. We sought to characterize potentially harmful supplement use by individual CKD status.
Study Design
Cross-sectional national survey (National Health and Nutrition Examination Survey, 1999-2008)
Setting & Participants
Community-based survey of 21,169 non-pregnant, non-institutionalized U.S. civilian adults (≥20 years)
CKD status (no CKD, at risk for CKD [presence of diabetes, hypertension and/or cardiovascular disease], stage 1/2 [albuminuria only (albumin-creatinine ratio ≥30 mg/g)], or stage 3/4 [estimated glomerular filtration rate of 15-59 ml/min/1.73 m2]).
Self-reported use of dietary supplements containing any of 37 herbs the National Kidney Foundation identified as potentially harmful in the setting of CKD.
Albuminuria and estimated glomerular filtration rate assessed from urine and blood samples; demographics and comorbid conditions assessed by standardized questionnaire.
An estimated 8.0% of U.S. adults reported potentially harmful supplement use within the last 30 days. Lower crude estimated prevalence of potentially harmful supplement use was associated with higher CKD severity (no CKD, 8.5%; at risk, 8.0%; stage 1/2, 6.1%; and stage 3/4, 6.2%; p<0.001). However, after adjustment for confounders, those with or at risk for CKD were as likely to use a potentially harmful supplement as those without CKD: at-risk OR, 0.93 (95% CI, 0.79 -1.09); stage 1/2 OR, 0.83 (95% CI, 0.64 -1.08); stage 3/4 OR, 0.87 (95% CI, 0.63 -1.18); all vs. no CKD.
Herb content was not available and the list of potentially harmful supplements examined is unlikely to be exhaustive.
The use of dietary supplements potentially harmful to people with CKD is common, regardless of CKD status. Healthcare providers should discuss the use and potential risks of supplements with patients with and at risk for CKD.
PMCID: PMC3628413  PMID: 23415417
17.  Association Between Adiponectin and Tumor Necrosis Factor-Alpha Levels at Eight to Fourteen Weeks Gestation and Maternal Glucose Tolerance: The Parity, Inflammation, and Diabetes Study 
Journal of Women's Health  2013;22(3):259-266.
Inflammation may influence gestational hyperglycemia, but to date, the data from observational studies is largely limited to results from the third trimester of pregnancy. Our objective was to evaluate first trimester adipocytokine levels. We sought to determine whether first trimester adiponectin and tumor necrosis factor-alpha (TNF)-alpha concentrations were independently associated and predictive of maternal glucose tolerance, as measured by the 1-hour glucose challenge test (GCT), after adjustment for maternal lifestyle behaviors and body mass index (BMI).
Material and Methods
Prospective study of pregnant women (n=211) enrolled in the Parity, Inflammation, and Diabetes Study. Nonfasting serum levels of adiponectin and TNF-r2 were measured at 8–14 weeks of pregnancy. GCT results were abstracted from electronic prenatal records. Multiple linear regression models were developed to determine the association of adiponectin and TNF-r2 levels with response to the GCT, adjusting for demographics, pregravid dietary intake and physical activity, first trimester BMI, and gestational weight gain.
At baseline, higher adiponectin concentrations were inversely and statistically significantly associated with maternal response to the GCT [regression coefficient (β) −0.68; 95% confidence interval (CI): −1.29, −0.06). Adjustment for lifestyle factors did not alter the association of adiponectin with the GCT (β −0.74; 95% CI: −1.43, −0.05). After adjustment for first trimester BMI, the association of adiponectin was attenuated and no longer significant (β −0.46; 95% CI: −1.15, 0.24). TNF-r2 levels were not associated with the GCT (β −0.003; 95% CI: −0.011, 0.005).
First trimester adiponectin levels are not predictive of the 1-hour GCT response, but may be a marker for the effect of maternal BMI on glucose response to the GCT.
PMCID: PMC3634147  PMID: 23480316
18.  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
19.  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
20.  Healthy Behaviors, Risk Factor Control and Awareness of Chronic Kidney Disease 
American journal of nephrology  2013;37(2):135-143.
The association between chronic kidney disease (CKD) awareness and healthy behaviors is unknown. We examined whether CKD self-recognition is associated with healthy behaviors and achieving risk-reduction targets known to decrease risk of cardiovascular morbidity and CKD progression.
CKD awareness, defined as a “yes” response to “Has a doctor or other health professional ever told you that you had kidney disease?”, was examined among adults with CKD (eGFR < 60 ml/min/1.73 m2) who participated in the REasons for Geographic and Racial Differences in Stroke study. Odds of participation in healthy behaviors (tobacco avoidance, avoidance of regular NSAID use, physical activity) and achievement of risk reduction targets (ACEI/ARB use, systolic blood pressure (SBP) control and glycemic control among those with diabetes) among those aware vs. unaware of their CKD were determined by logistic regression, controlling for socio-demographics, access to care and co-morbid conditions. SBP control was defined as < 130 mmHg (primary definition) or < 140 mmHg (secondary definition).
Of 2,615 participants, only 6% (n=166) were aware of having CKD. Those who were aware had 82% higher odds of tobacco avoidance compared to those unaware [adjusted odds ratio =1.82, 95% CI (1.02–3.24)]. CKD awareness was not associated other healthy behaviors or achievement of risk-reduction targets.
Awareness of CKD was only associated with participation in one healthy behavior and was not associated with achievement of risk-reduction targets. To encourage adoption of healthy behaviors, a better understanding of barriers to participation in CKD-healthy behaviors is needed. Keywords: chronic kidney disease, awareness, behaviors, self-management
PMCID: PMC3649001  PMID: 23392070
Chronic kidney disease; awareness; self-management; behaviors
21.  Chronic Kidney Disease Identification in a High-Risk Urban Population: Does Automated eGFR Reporting Make a Difference? 
Whether automated estimated glomerular filtration rate (eGFR) reporting for patients is associated with improved provider recognition of chronic kidney disease (CKD), as measured by diagnostic coding of CKD in those with laboratory evidence of the disease, has not been explored in a poor, ethnically diverse, high-risk urban patient population. A retrospective cohort of 237 adult patients (≥20 years) with incident CKD (≥1 eGFR ≥60 ml/min/1.73 m2, followed by ≥2 eGFRs <60 ml/min/1.73 m2 ≥3 months apart)—pre- or postautomated eGFR reporting—was identified within the San Francisco Department of Public Health Community Health Network (January 2005–July 2009). Patients were considered coded if any ICD-9-CM diagnostic codes for CKD (585.x), other kidney disease (580.x–581.x, 586.x), or diabetes (250.4) or hypertension (403.x, 404.x) CKD were present in the medical record within 6 months of incident CKD. Multivariable logistic regression was used to obtain adjusted odds ratios (ORs) for CKD coding. We found that, pre-eGFR reporting, 42.5 % of incident CKD patients were coded for CKD. Female gender, increased age, and non-Black race were associated with lower serum creatinine and lower prevalence of coding but comparable eGFR. Prevalence of coding was not statistically significantly higher overall (49.6 %, P = 0.27) or in subgroups after the institution of automated eGFR reporting. However, gaps in coding by age and gender were narrowed post-eGFR, even after adjustment for sociodemographic and clinical characteristics: 47.9 % of those <65 and 30.3 % of those ≥65 were coded pre-eGFR, compared to 49.0 % and 52.0 % post-eGFR (OR = 0.43 and 1.16); similarly, 53.2 % of males and 25.4 % of females were coded pre-eGFR compared to 52.8 % and 44.0 % post-eGFR (OR 0.28 vs. 0.64). Blacks were more likely to be coded in the post-eGFR period: OR = 1.08 and 1.43 (Pinteraction > 0.05). Automated eGFR reporting may help improve CKD recognition, but it is not sufficient to resolve underidentification of CKD by safety net providers.
PMCID: PMC3531349  PMID: 22684427
Chronic kidney disease; Diagnostic coding; Estimated glomerular filtration rate; Female; African American
22.  Low Income and Albuminuria Among REGARDS (Reasons for Geographic and Racial Differences in Stroke) Study Participants 
Albuminuria is an important risk factor for progressive CKD and is more prevalent among black than among white adults. We sought to determine the association between low income and albuminuria, and if this association differs for blacks and whites.
Study Design
Cross-sectional study.
Setting & Participants
9,144 black and 13,684 white U.S. adults aged 45 years and older in the population-based REasons for Geographic and Racial Differences in Stroke (REGARDS) study.
Self-reported annual household income category (≥$75,000, 35,000 – $74,999, $20,000 – $34,999, and <$20,000); black and white race.
Outcomes & Measurements
Albuminuria defined as high (30 to 300 mg/g) or very high (>300 mg/g) urinary albumin-creatinine ratio (ACR). Multinomial logistic regression used to examine the race-stratified association between categories of income and albuminuria (normal, high, or very high ACR).
Overall, geometric mean ACR was 10.2 mg/g, and was higher for blacks (11.8 mg/g) than for whites (9.3 mg/g), p <0.001. Lower income was associated with a higher prevalence of albuminuria for both whites and blacks in unadjusted analyses. After adjustment for demographics, lifestyle factors, comorbid illnesses and estimated glomerular filtration rate, there was a trend towards a stronger association between lower income levels and high ACR among blacks [ORs of 1.38 (95% CI, 1.07 – 1.77), 1.36 (95% CI, 1.05 – 1.75), and 1.58 (95% CI, 1.21–2.05), for income levels of $35,000 – $74,999, $20,000 – $34,999, and <$20,000, respectively; reference group is those with income ≥$75,000] compared to whites [ORs of 0.95 (95% CI, 0.81 – 1.12), 0.95 (95% CI, 0.79 – 1.14), and 1.26 (95% CI, 1.02 – 1.55), respectively]; P interaction 0.08 between race and income. Results were similar for very high ACR, and subgroups of participants with diabetes or hypertension.
Cross-sectional design; not all REGARDS participants provided their annual income.
Lower income may be more strongly associated with albuminuria among blacks than among whites, and may be a determinant of racial disparities in albuminuria.
PMCID: PMC3448844  PMID: 22694949
Race; albuminuria; poverty; chronic kidney disease; socioeconomic status; disparity
23.  Factors Associated With Depressive Symptoms and Use of Antidepressant Medications Among Participants in the Chronic Renal Insufficiency Cohort (CRIC) and Hispanic-CRIC Studies 
Depressive symptoms are correlated with poor health outcomes in adults with chronic kidney disease (CKD). The prevalence, severity, and treatment of depressive symptoms and potential risk factors, including level of kidney function, in diverse populations with CKD have not been well studied.
Study Design
Cross-sectional analysis
Settings and Participants
Participants at enrollment into the Chronic Renal Insufficiency Cohort (CRIC) and Hispanic-CRIC (H-CRIC) Studies. CRIC enrolled Hispanics and non-Hispanics at seven centers from 2003-2007, and H-CRIC enrolled Hispanics at the University of Illinois from 2005-2008.
Depressive symptoms measured by Beck Depression Inventory (BDI)
Demographic and clinical factors
Elevated depressive symptoms (BDI >= 11) and antidepressant medication use
Among 3853 participants, 28.5% had evidence of elevated depressive symptoms and 18.2% were using antidepressant medications; 30.8% of persons with elevated depressive symptoms were using antidepressants. The prevalence of elevated depressive symptoms varied by level of kidney function: 25.2% among participants with eGFR ≥ 60 ml/min/1.73m2, and 35.1% of those with eGFR < 30 ml/min/1.73m2. Lower eGFR (OR per 10 ml/min/1.73m2 decrease, 1.09; 95% CI, 1.03-1.16), Hispanic ethnicity (OR, 1.65; 95% CI, 1.12-2.45), and non-Hispanic black race (OR, 1.43; 95% CI, 1.17-1.74) were each associated with increased odds of elevated depressive symptoms after controlling for other factors. In regression analyses incorporating BDI score, while female sex was associated with a greater odds of antidepressant use, Hispanic ethnicity, non-Hispanic black race, and higher levels of urine albumin were associated with decreased odds of antidepressant use (p<0.05 for each).
Absence of clinical diagnosis of depression and use of non-pharmacologic treatments
Although elevated depressive symptoms were common in individuals with CKD, use of antidepressant medications is low. African Americans, Hispanics, and individuals with more advanced CKD had higher odds of elevated depressive symptoms and lower odds of antidepressant medication use.
PMCID: PMC3378778  PMID: 22497791
24.  Retained organic solutes, patient characteristics and all-cause and cardiovascular mortality in hemodialysis: results from the retained organic solutes and clinical outcomes (ROSCO) investigators 
BMC Nephrology  2013;14:134.
Multiple solutes are retained in uremia, but it is currently unclear which solutes are toxic. Small studies suggest that protein-bound solutes, such as p-cresol sulfate and indoxyl sulfate and intracellular solutes, such as methylamine (MMA) and dimethylamine (DMA), may be toxic. Our objective was to test whether elevated levels of these solutes were associated with mortality.
We conducted a prospective cohort study in 521 U.S. incident hemodialysis patients to evaluate associations between these solutes and all-cause and cardiovascular mortality. P-cresol sulfate, indoxyl sulfate, MMA and DMA levels were measured from frozen plasma samples obtained 2 to 6 months after initiation of dialysis. Mortality data was available through 2004 using the National Death Index.
Elevated (greater than the population median) p-cresol sulfate, MMA or DMA levels were not associated with all-cause or cardiovascular mortality. Elevated indoxyl sulfate levels were associated with all-cause mortality but not cardiovascular mortality (hazard ratio 1.30 (95% confidence interval 1.01, 1.69) p-value 0.043).
In this cohort of 521 incident hemodialysis patients, only elevated indoxyl sulfate levels were associated with all-cause mortality. Further research is needed to identify causes of the toxicity of uremia to provide better care for patients with kidney disease.
PMCID: PMC3698023  PMID: 23806101
All-cause Mortality; Cardiovascular Mortality; Dialysis Outcomes; Indoxyl Sulfate; P-cresol Sulfate; Uremic Solutes
25.  Association Between Hospitals Caring for a Disproportionately High Percentage of Minority Trauma Patients and Increased Mortality 
To determine whether there is an increased odds of mortality among trauma patients treated at hospitals with higher proportions of minority patients (ie, black and Hispanic patients combined).
Hospitals were categorized on the basis of the percentage of minority patients admitted with trauma. The adjusted odds of in-hospital mortality were compared between hospitals with less than 25% of patients who were minorities (the reference group) and hospitals with 25% to 50% of patients who were minorities and hospitals with more than 50% of patients who were minorities. Multivariate logistic regression (with generalized linear modeling and a cluster-correlated robust estimate of variance) was used to control for multiple patient and injury severity characteristics.
A total of 434 hospitals in the National Trauma Data Bank.
Patients aged 18 to 64 years whose medical records were included in the National Trauma Data Bank for the years 2007 and 2008 with an Injury Severity Score of 9 or greater and who were white, black, or Hispanic.
Main Outcome Measures
Crude mortality and adjusted odds of in-hospital mortality.
A total of 311 568 patients were examined. Hospitals in which the percentage of minority patients was more than 50% also had younger patients, fewer female patients, more patients with penetrating trauma, and the highest crude mortality. After adjustment for potential confounders, patients treated at hospitals in which the percentage of minority patients was 25% to 50% and at hospitals in which the percentage of minority patients was more than 50% demonstrated increased odds of death (adjusted odds ratio, 1.16 [95% confidence interval, 1.01–1.34] and adjusted odds ratio, 1.37 [95% confidence interval, 1.16–1.61], respectively), compared with the reference group. This disparity increased further on subset analysis of patients with a blunt injury. Uninsured patients had significantly increased odds of mortality within all 3 hospital groups.
Patients treated at hospitals with higher proportions of minority trauma patients have increased odds of dying, even after adjusting for potential confounders. Differences in outcomes between trauma hospitals may partly explain racial disparities.
PMCID: PMC3684151  PMID: 21930976

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