Search tips
Search criteria

Results 1-25 (48)

Clipboard (0)

Select a Filter Below

Year of Publication
1.  Primary Care Detection of Chronic Kidney Disease in Adults with Type-2 Diabetes: The ADD-CKD Study (Awareness, Detection and Drug Therapy in Type 2 Diabetes and Chronic Kidney Disease) 
PLoS ONE  2014;9(11):e110535.
This US, multicenter, observational study assessed the CKD prevalence in adult patients with type-2 diabetes mellitus (T2DM) and characterized the proportion of detected and undiagnosed CKD in the primary care setting using the following: a clinician survey; a patient physical exam and medical history; a single blood draw for estimated glomerular filtration rate (eGFR) and glycosolated hemoglobin (HbA1c); urine dipstick for protein; urine albumin-creatinine ratio (ACR); two patient quality of life questionnaires; and a 15-month medical record review. The study consisted of 9339 adults with T2DM and 466 investigator sites. Of the 9339 enrolled, 9307 had complete data collection for analysis. The 15-month retrospective review showed urine protein, urine ACR, and eGFR testing were not performed in 51.4%, 52.9% and 15.2% of individuals, respectively. Of the 9307 patients, 5036 (54.1%) had Stage 1–5 CKD based on eGFR and albuminuria; however, only 607 (12.1%) of those patients were identified as having CKD by their clinicians. Clinicians were more successful in diagnosing patients with Stage 3–5 CKD than Stages 1 and 2. There were no differences in clinicians’ likelihood of identification of CKD based on practice setting, number of years in practice, or self-reported patients seen per week. Awareness or patient self-reported CKD was 81.1% with practitioner detection versus 2.6% in the absence of diagnosis. Primary care of T2DM demonstrates recommended urine CKD testing is underutilized, and CKD is significantly under-diagnosed. This is the first study to show CKD detection is associated with awareness.
PMCID: PMC4245114  PMID: 25427285
2.  Anemia and Associated Clinical Outcomes in Patients with Heart Failure Due to Reduced Left Ventricular Systolic Function 
Clinical cardiology  2013;36(10):611-620.
Anemia is associated with decreased functional capacity, reduced quality of life, and worsened outcomes among patients with heart failure (HF) due to reduced left ventricular ejection fraction (HFREF). We sought to evaluate the independent effect of anemia on clinical outcomes among those with HFREF.
The HF-ACTION trial was a prospective, randomized trial of exercise therapy versus usual care in 2331 patients with HFREF. Patients with New York Heart Association class 2–4 HF and left ventricular ejection fractions of ≤ 35% were recruited. Hemoglobin (Hb) was measured up to one year prior to entry and was stratified by quintile. Anemia was defined as baseline Hb < 13 g/dl and <12 g/dl in men and women, respectively. Hb was assessed in two models; a global prediction model that had been previously developed and a modified model including variables associated with anemia and the studied outcomes.
Hemoglobin was available at baseline in 1763 subjects (76% of total study population); their median age was 59.0 years, 73% were male, and 62% were Caucasian. The prevalence of anemia was 515/1763 (29%). Older age, female gender, African American race, diabetes, hypertension, and lower estimated glomerular filtration rates were all more frequent in lower Hb quintiles. Over a median follow-up of 30 months, the primary outcome of all-cause mortality or all-cause hospitalization occurred in 78% of those with anemia and 64% in those without, p<0.001. The secondary outcomes of all-cause mortality alone, cardiovascular mortality or cardiovascular hospitalization, and cardiovascular mortality or HF hospitalization occurred in 23 % vs 15%, 67% vs 54%, and 44 vs 29%, respectively, p<0.001. Heart failure hospitalizations occurred in 36% vs 22%, and urgent outpatient visits for HF exacerbations occurred in 67% and 55%, respectively, p<0.001. For the global model, there was an association observed for anemia and all-cause mortality or hospitalization, adjusted hazard ratio (HR)=1.15, 95% CI 1.01–1.32, p=0.04, but other outcomes were not significant at p<0.05. In the modified model, the adjusted HR for anemia and the primary outcome of all-cause mortality or all-cause hospitalization was 1.25, 95% CI 1.10–1.42, p<0.001. There were independent associations between anemia and all-cause death, HR=1.11, 95% CI 0.87–1.42, p=0.38; cardiovascular death or cardiovascular hospitalization, HR=1.16, 95% CI 1.01–1.33, p=0.035; and cardiovascular death and heart failure hospitalization, HR=1.27, 95% CI 1.06–1.51, p=0.008.
Anemia modestly is associated with increased rates of death, hospitalization, and HF exacerbation in patients with chronic HFREF. After adjusting for other important covariates, anemia is independently associated with an excess hazard for all-cause mortality and all-cause hospitalization. Anemia is also associated with combinations of cardiovascular death and cardiovascular/heart failure hospitalizations as composite endpoints.
PMCID: PMC4008125  PMID: 23929781
heart failure; chronic kidney disease; anemia; glomerular filtration rate; renal insufficiency; hospitalization; mortality
3.  Derivation and validation of cutoffs for clinical use of cell cycle arrest biomarkers 
Nephrology Dialysis Transplantation  2014;29(11):2054-2061.
Acute kidney injury (AKI) remains a deadly condition. Tissue inhibitor of metalloproteinases (TIMP)-2 and insulin-like growth factor binding protein (IGFBP)7 are two recently discovered urinary biomarkers for AKI. We now report on the development, and diagnostic accuracy of two clinical cutoffs for a test using these markers.
We derived cutoffs based on sensitivity and specificity for prediction of Kidney Disease: Improving Global Outcomes Stages 2–3 AKI within 12 h using data from a previously published multicenter cohort (Sapphire). Next, we verified these cutoffs in a new study (Opal) enrolling 154 critically ill adults from six sites in the USA.
One hundred subjects (14%) in Sapphire and 27 (18%) in Opal met the primary end point. The results of the Opal study replicated those of Sapphire. Relative risk (95% CI) in both studies for subjects testing at ≤0.3 versus >0.3–2 were 4.7 (1.5–16) and 4.4 (2.5–8.7), or 12 (4.2–40) and 18 (10–37) for ≤0.3 versus >2. For the 0.3 cutoff, sensitivity was 89% in both studies, and specificity 50 and 53%. For 2.0, sensitivity was 42 and 44%, and specificity 95 and 90%.
Urinary [TIMP-2]•[IGFBP7] values of 0.3 or greater identify patients at high risk and those >2 at highest risk for AKI and provide new information to support clinical decision-making.
Clinical Trials Registration # NCT01209169 (Sapphire) and NCT01846884 (Opal).
PMCID: PMC4209880  PMID: 25237065
acute kidney injury; acute renal failure; biomarkers; insulin-like growth factor binding protein (IGFBP)7 and tissue inhibitor of metalloproteinases (TIMP)-2; sensitivity and specificity (MeSH)
4.  Risk Factors for ESRD in Individuals With Preserved Estimated GFR With and Without Albuminuria: Results From the Kidney Early Evaluation Program (KEEP) 
Given the increasing costs and poor outcomes of end-stage renal disease (ESRD), we sought to identify risk factors for ESRD in people with preserved estimated glomerular filtration rate (eGFR), with or without albuminuria, who were at high risk of ESRD.
This cohort study included participants in the National Kidney Foundation’s Kidney Early Evaluation Program (KEEP) with eGFR ≥60 mL/min/1.73 m2 at baseline stratified by the presence or absence of albuminuria. The Chronic Kidney Disease Epidemiology Collaboration equation was used to calculate eGFR. Urine was tested for albuminuria by semiquantitative dipstick. The outcome was the development of treated chronic kidney failure, defined as initiation of maintenance dialysis therapy or kidney transplantation, determined by linkage to the US Renal Data System. We used a Cox model with the Fine-Gray method to assess risk factors for treated chronic kidney failure while accounting for the competing risk of death.
During a median follow-up of 4.8 years, 126 of 13,923 participants with albuminuria (16/10,000 patient-years) and 56 of 109,135 participants without albuminuria (1.1/10,000 patient-years) developed treated chronic kidney failure. Diabetes was a strong risk factor for developing treated chronic kidney failure in participants with and without albuminuria (adjusted HRs of 9.3 [95% CI, 5.7–15.3] and 7.8 [95% CI, 4.1–14.8], respectively). Black race, lower eGFR, and higher systolic blood pressure also were associated with higher adjusted risks of developing treated chronic kidney failure.
In a diverse high-risk cohort of KEEP participants with preserved eGFR, we showed that diabetes, higher systolic blood pressure, lower eGFR, and black race were risk factors for developing treated chronic kidney failure irrespective of albuminuria status, although the absolute risk of kidney failure in participants without albuminuria was very low. Our findings support testing for kidney disease in high-risk populations, which often have otherwise unrecognized kidney disease.
PMCID: PMC4117734  PMID: 23507268
Albuminuria; blood pressure; chronic kidney disease; diabetes; dialysis risk factors; end-stage renal disease; public health
5.  No independent association of serum phosphorus with risk for death or progression to end-stage renal disease in a large screen for chronic kidney disease 
Kidney international  2013;84(5):989-997.
Whether higher serum phosphorus levels are associated with a higher risk for death and/or progression of chronic kidney disease (CKD) is not well established, and whether the association is confounded by access and barriers to care is unknown. To answer these questions, data of 10,672 individuals identified to have CKD (estimated glomerular filtration rate <60 ml/min per 1.73 m2) from those participating in a community-based screening program were analyzed. Over a median follow-up of 2.3 years, there was no association between quartiles of serum phosphorus and all-cause mortality (adjusted hazards ratio for serum phosphorus over 3.3 to 3.7, over 3.7 to 4.1, and over 4.1 mg/dl, respectively: 1.22 (0.95–1.56), 1.00 (0.76–1.32), and 1.00 (0.75–1.33); reference, serum phosphorus of 3.3 mg/dl and below). Individuals in the highest quartile for serum phosphorus had a significantly higher risk for progression to end-stage renal disease (ESRD) (unadjusted hazards ratio, 6.72 (4.16–10.85)); however, the risk became nonsignificant on adjustment for potential confounders. There was no appreciable change in hazards ratio with inclusion of variables related to access and barriers to care. Additional analyses in subgroups based on 12 different variables yielded similar negative associations. Thus, in the largest cohort of individuals with early-stage CKD to date, we could not validate an independent association of serum phosphorus with risk for death or progression to ESRD.
PMCID: PMC4103660  PMID: 23615501
barrier to care; cardiovascular disease; chronic kidney disease; end-stage renal disease; mortality; phosphorus
6.  Continuous versus bolus intermittent loop diuretic infusion in acutely decompensated heart failure: a prospective randomized trial 
Critical Care  2014;18(3):R134.
Intravenous loop diuretics are a cornerstone of therapy in acutely decompensated heart failure (ADHF). We sought to determine if there are any differences in clinical outcomes between intravenous bolus and continuous infusion of loop diuretics.
Subjects with ADHF within 12 hours of hospital admission were randomly assigned to continuous infusion or twice daily bolus therapy with furosemide. There were three co-primary endpoints assessed from admission to discharge: the mean paired changes in serum creatinine, estimated glomerular filtration rate (eGFR), and reduction in B-type natriuretic peptide (BNP). Secondary endpoints included the rate of acute kidney injury (AKI), change in body weight and six months follow-up evaluation after discharge.
A total of 43 received a continuous infusion and 39 were assigned to bolus treatment. At discharge, the mean change in serum creatinine was higher (+0.8 ± 0.4 versus -0.8 ± 0.3 mg/dl P <0.01), and eGFR was lower (-9 ± 7 versus +5 ± 6 ml/min/1.73 m2P <0.05) in the continuous arm. There was no significant difference in the degree of weight loss (-4.1 ± 1.9 versus -3.5 ± 2.4 kg P = 0.23). The continuous infusion arm had a greater reduction in BNP over the hospital course, (-576 ± 655 versus -181 ± 527 pg/ml P = 0.02). The rates of AKI were comparable (22% and 15% P = 0.3) between the two groups. There was more frequent use of hypertonic saline solutions for hyponatremia (33% versus 18% P <0.01), intravenous dopamine infusions (35% versus 23% P = 0.02), and the hospital length of stay was longer in the continuous infusion group (14. 3 ± 5 versus 11.5 ± 4 days, P <0.03). At 6 months there were higher rates of re-admission or death in the continuous infusion group, 58% versus 23%, (P = 0.001) and this mode of treatment independently associated with this outcome after adjusting for baseline and intermediate variables (adjusted hazard ratio = 2.57, 95% confidence interval, 1.01 to 6.58 P = 0.04).
In the setting of ADHF, continuous infusion of loop diuretics resulted in greater reductions in BNP from admission to discharge. However, this appeared to occur at the consequence of worsened renal filtration function, use of additional treatment, and higher rates of rehospitalization or death at six months.
Trial registration NCT01441245. Registered 23 September 2011.
PMCID: PMC4227080  PMID: 24974232
7.  Management of gastrointestinal bleeding in patients anticoagulated with dabigatran compared with warfarin: a retrospective, comparative case review 
Dabigatran etexilate, was found to be effective for stroke prevention in patients with non-valvular atrial fibrillation. Given its predictable pharmacodynamics, laboratory monitoring is not required. Moreover, the risks of overall bleeding, intracranial bleeding, and life-threatening hemorrhage from dabigatran were found to be lower than warfarin. However, a higher risk of gastrointestinal (GI) bleeding caused by dabigatran from the randomized evaluation of long-term anticoagulant therapy (RE-LY) trial has raised the concern regarding clinical outcomes of patients with GI bleeding caused by dabigatran compared with warfarin.
We retrospectively studied patients who were hospitalized for GI bleeding from dabigatran compared with warfarin with therapeutic anticoagulation monitoring during 2009 to 2012. Initial laboratory findings at presentation, number of transfused packed red blood cells (PRBCs), acute kidney injury, clinical outcomes (e.g., hypotension, tachycardia), length of stay, and death were compared.
Thirteen patients taking dabigatran and 26 patients who were on warfarin with therapeutic international normalized ratio (INR) were hospitalized during the study period. Demographic data and baseline parameters between the two groups were not significantly different except for concurrent aspirin use (84.6% vs. 50%, P=0.036). Fifty-four percent of patients taking dabigatran did not have activated partial thromboplastin time (aPTT) level performed at presentation (7/13). The patients with GI bleeding from warfarin received significantly more PRBC transfusions compared with the dabigatran group (1.92±2.2 vs. 0.69±1.1 units, P=0.024). After controlling for initial hemoglobin and history of chronic kidney disease by using multivariate analysis, the patients in the warfarin group were likely to receive more PRBC. Hypotension at presentation was more common in GI bleeding caused by warfarin than dabigatran but the P value was insignificant (30.8% vs. 7.7%, P=0.11). Nevertheless, no differences in clinical outcomes or length of stay were found between the two groups.
From our data, the patients with GI bleeding from dabigatran were likely to receive fewer PRBC transfusions; however, clinical outcomes and length of stay were comparable to GI bleeding caused by warfarin. Our sample generalizes to an elderly population (mean age of 77.9±10 years old) with creatinine clearance (CrCl) >30 mL/min who experience GI bleeding during chronic anticoagulation.
PMCID: PMC4069982  PMID: 25009791
Dabigatran; direct thrombin inhibitor; gastrointestinal bleeding (GI bleeding); warfarin
9.  Endothelial Cell Autoantibodies in Predicting Declining Renal Function, End-Stage Renal Disease, or Death in Adult Type 2 Diabetic Nephropathy 
Albuminuria is a strong predictor of diabetic nephropathy chronic kidney disease outcomes. Yet, therapeutic albuminuria-lowering has not consistently translated into a reduction in clinical events suggesting the involvement of additional pathogenic factors. Our hypothesis is that anti-endothelial cell autoantibodies play a role in development and progression in diabetic nephropathy. We determined anti-endothelial cell antibody (AECA) bioactivity in protein A-elutes of baseline plasma in 305 participants in the VA NEPHRON-D study, a randomized trial of angiotensin receptor blocker (ARB) or dual ARB plus angiotensin-converting enzyme inhibitor therapy in type 2 diabetes with proteinuric nephropathy. Thirty-eight percent (117/305) of participants had significantly reduced endothelial cell survival ( ≤80%) in the IgG fraction of plasma. A VA NEPHRON-D primary endpoint [end-stage renal disease (ESRD), significant reduction in estimated glomerular filtration rate, or death] was experienced by 58 individuals. In adjusted Cox regression analysis, there was a significant interaction effect of baseline anti-endothelial cell-mediated cell survival and albuminuria on the hazard rate (HR) for primary composite endpoint (P = 0.017). Participants lacking strongly inhibitory antibodies with albuminuria ≥1 g/g creatinine had a significantly increased primary event hazard ratio, 3.41 – 95% confidence intervals (CI 1.84–6.33; P < 0.001) compared to those lacking strongly inhibitory antibodies with lower baseline albuminuria ( <1 g/g creatinine). These results suggest that anti-endothelial cell antibodies interact significantly with albuminuria in predicting the composite endpoint of death, ESRD, or substantial decline in renal function in older, adult type 2 diabetic nephropathy.
PMCID: PMC4127944  PMID: 25157242
endothelium; autoantibodies; type 2 diabetes; nephropathy; chronic kidney disease
10.  Implementation of Novel Biomarkers in the Diagnosis, Prognosis, and Management of Acute Kidney Injury: Executive Summary from the Tenth Consensus Conference of the Acute Dialysis Quality Initiative (ADQI) 
Contributions to nephrology  2013;182:10.1159/000349962.
Detection of acute kidney injury is undergoing a dynamic revolution of biomarker technology allowing greater, earlier, and more accurate determination of diagnosis, prognosis, and with powerful implication for management. Biomarkers can be broadly considered as any measurable biologic entity or process that allows differentiation between normal function and injury or disease. The ADQI (Acute Dialysis Quality Initiative) had its Ninth Consensus Conference dedicated to synthesis and formulation of the existing literature on biomarkers for the detection of acute kidney injury in a variety of settings. In the papers that accompany this summary, ADQI workgroups fully develop key concepts from a summary of the literature in the domains of early diagnosis, differential diagnosis, prognosis and management, and concurrent physiologic and imaging measures.
PMCID: PMC3856225  PMID: 23689652
11.  Hyperacute drug-induced hepatitis with intravenous amiodarone: case report and review of the literature 
Amiodarone is a benzofuran class III antiarrhythmic drug used to treat a wide spectrum of ventricular tachyarrhythmias. The parenteral formulation is prepared in polysorbate 80 diluent. We report an unusual case of acute elevation of aminotransaminase concentrations after the initiation of intravenous amiodarone. An 88-year-old Caucasian female developed acute hepatitis and renal failure after initiating intravenous amiodarone for atrial fibrillation with a rapid ventricular response in the setting of acutely decompensated heart failure and hepatic congestion. Liver transaminases returned to baseline within 7 days after discontinuing the drug. Researchers hypothesized that this type of injury is related to liver ischemia with possible superimposed direct drug toxicity. The CIOMS/RUCAM scale identifies our patient’s acute hepatitis as a highly probable adverse drug reaction. Future research is needed to understand the mechanisms by which hyperacute drug toxicity occurs in the setting of impaired hepatic perfusion and venous congestion.
PMCID: PMC3792591  PMID: 24109195
intravenous amiodarone; acute hepatotoxicity; liver transaminases; drug-induced liver toxicity
12.  Association Between Lack of Health Insurance and Risk of Death and ESRD: Results From the Kidney Early Evaluation Program (KEEP) 
Uninsured adults in the United States have poor access to health care services and worse health outcomes than insured adults. Little is known about the association between lack of insurance and chronic kidney disease (CKD) progression to end-stage renal disease (ESRD) or death in patients at high risk of kidney disease. We used 2000–2011 data from the National Kidney Foundation’s Kidney Early Evaluation Program (KEEP) to examine this association.
The study population included KEEP participants younger than 65 years. Outcomes were time to ESRD (chronic kidney failure treated by renal replacement therapy) and time to death. Incident ESRD was ascertained by linkage to the US Renal Data System, and vital status, by linkage to the Social Security Administration Death Master File. We used Cox proportional hazard regression to examine the association between insurance and risk of death or ESRD after adjusting for demographic variables.
Of 86,588 participants, 27.8% had no form of insurance, 10.3% had public insurance, and 61.9% had private insurance; 15.0% had CKD (defined as estimated glomerular filtration rate <60 mL/min/1.73 m2 or urine albumin-creatinine ratio ≥30 mg/g), 63.3% had hypertension, and 27.7% had diabetes. Of participants with CKD, 29.3% had no health insurance. Participants without insurance were younger, more likely to be Hispanic and to have 12 or fewer years of education, and less likely to have seen a physician in the past year. After adjustment for demographic characteristics, uninsured KEEP participants were 82% more likely than privately insured participants to die (HR, 1.82; 95% CI, 1.56–2.12; P < 0.001) and 72% more likely to develop ESRD (HR, 1.72; 95% CI, 1.33–2.22; P < 0.001). The association between insurance and outcomes varied by CKD stage.
Lack of insurance is an independent risk factor for early death and ESRD in this population at high risk of kidney disease. Considering the high morbidity and mortality and increasing cost associated with ESRD, access to appropriate health insurance coverage is warranted.
PMCID: PMC3739048  PMID: 23507267
Chronic kidney disease; end-stage renal disease; health insurance; mortality; public health
13.  Awareness of Kidney Disease and Relationship to End-Stage Renal Disease and Mortality 
The American Journal of Medicine  2012;125(7):661-669.
Patients with chronic kidney disease are often reported to be unaware. We prospectively evaluated the association between awareness of kidney disease to end-stage renal disease and mortality.
We utilized 2000–2009 data from the National Kidney Foundation-Kidney Early Evaluation Program (KEEP™). Mortality was determined by cross reference to the Social Security Administration Death Master File, and development of end-stage by cross reference with the United States Renal Data System.
Of 109,285 participants, 28,244 (26%) had chronic kidney disease defined by albuminuria or eGFR <60ml/min/1.73m2. Only 9% (n=2660) reported being aware of kidney disease. Compared to those who were not aware, participants aware of chronic kidney disease had lower eGFR (49 vs 62ml/min/1.73m2) and a higher prevalence of albuminuria (52 vs 46%), diabetes (47 vs 42%), cardiovascular disease (43 vs 28%) and cancer (23 vs 14%). Over 8.5 years of follow-up, aware participants compared to those unaware had a lower rate of survival for end-stage (83% and 96%) and mortality (78 vs 81%), p<0.001 respectively. After adjustment for demographics, socioeconomic factors, comorbidity, and severity of kidney disease, aware participants continued to demonstrate an increased risk for end-stage renal disease [hazard ratio (95% CI) 1.37(1.07–1.75); p<0.0123] and mortality [1.27(1.07–1.52); p<0.0077] relative to unaware participants with chronic kidney disease.
Among persons identified as having chronic kidney disease at a health screening, only a small proportion had been made aware of their diagnosis previously by clinicians. This subgroup was at a disproportionately high risk for mortality and end-stage renal disease.
PMCID: PMC3383388  PMID: 22626510
KEEP; CKD; awareness; ESRD; mortality
14.  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
15.  The Association between Parathyroid Hormone Levels and Hemoglobin in Diabetic and Nondiabetic Participants in the National Kidney Foundation's Kidney Early Evaluation Program 
Cardiorenal Medicine  2013;3(2):120-127.
Both anemia and secondary hyperparathyroidism are reflections of hormonal failure in chronic kidney disease (CKD). While the association of elevated levels of parathyroid hormone (PTH) and anemia has been studied among those with advanced CKD, less is known about this association in mild-to-moderate CKD.
In a cross-sectional analysis, the relationship between PTH and hemoglobin levels was investigated in 10,750 participants in the National Kidney Foundation's Kidney Early Evaluation Program with an estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m2.
In the unadjusted analysis, higher PTH levels were associated with lower hemoglobin levels. However, after multivariable adjustment for age, race, gender, smoking status, education, cardiovascular disease, diabetes, hypertension, cancer, albuminuria, BMI, baseline eGFR, calcium, and phosphorus, the direction of association changed. As compared to the first PTH quintile, hemoglobin levels were 0.09 g/dl (95% CI: 0.01-0.18), 0.15 g/dl (95% CI: 0.07-0.24), 0.18 g/dl (95% CI: 0.09-0.26), and 0.13 g/dl (95% CI: 0.07-0.25) higher for the second, third, fourth, and fifth quintiles, respectively. Similarly, each standard deviation increase in natural log transformed PTH was associated with a 0.06 g/dl (95% CI: 0.03-0.09, p = 0.0003) increase in hemoglobin. However, a significant effect modification was seen for diabetes (p = 0.0003). Each standard deviation increase in natural log transformed PTH was associated with a 0.10 g/dl (95% CI: 0.054-0.138, p < 0.0001) increase in hemoglobin, while no association was seen among those without diabetes mellitus.
After multivariable adjustment, there was a small positive association between PTH and hemoglobin among diabetics but not among nondiabetics.
PMCID: PMC3721130  PMID: 23922552
Chronic kidney disease; Anemia; Secondary hyperparathyroidism

16.  Physician Utilization, Risk-Factor Control, and CKD Progression Among Participants in the Kidney Early Evaluation Program (KEEP) 
Chronic kidney disease (CKD) is a well-known risk factor for cardiovascular mortality, but little is known about the association between physician utilization and cardiovascular disease risk-factor control in patients with CKD. We used 2005–2010 data from the National Kidney Foundation’s Kidney Early Evaluation Program (KEEP) to examine this association at first and subsequent screenings.
Control of risk factors was defined as control of blood pressure, glycemia, and cholesterol levels. We used multinomial logistic regression to examine the association between participant characteristics and seeing a nephrologist after adjusting for kidney function and paired t tests or McNemar tests to compare characteristics at first and second screenings.
Of 90,009 participants, 61.3% had a primary care physician only, 2.9% had seen a nephrologist, and 15.3% had seen another specialist. The presence of 3 risk factors (hypertension, diabetes, and hypercholesterolemia) increased from 26.8% in participants with CKD stages 1–2 to 31.9% in those with stages 4–5. Target levels of all risk factors were achieved in 7.2% of participants without a physician, 8.3% of those with a primary care physician only, 9.9% of those with a nephrologist, and 10.3% of those with another specialist. Of up to 7,025 participants who met at least one criterion for nephrology consultation at first screening, only 12.3% reported seeing a nephrologist. Insurance coverage was associated strongly with seeing a nephrologist. Of participants who met criteria for nephrology consultation, 406 (5.8%) returned for a second screening, of whom 19.7% saw a nephrologist. The percentage of participants with all risk factors controlled was higher at the second screening (20.9% vs 13.3%).
Control of cardiovascular risk factors is poor in the KEEP population. The percentage of participants seeing a nephrologist is low, although better after the first screening. Identifying communication barriers between nephrologists and primary care physicians may be a new focus for KEEP.
PMCID: PMC3654535  PMID: 22339899
Cardiovascular disease risk factors; chronic kidney disease; nephrologist care; primary care
17.  In reply 
Mayo Clinic Proceedings  2012;87(11):1133-1134.
PMCID: PMC3532680
19.  Urine Catalytic Iron and Neutrophil Gelatinase-Associated Lipocalin as Companion Early Markers of Acute Kidney Injury after Cardiac Surgery: A Prospective Pilot Study 
Cardiorenal Medicine  2013;3(1):7-16.
Open heart surgery with cardiopulmonary bypass is recognized as a common cause of acute kidney injury (AKI). The conventional biomarker creatinine is not sensitive enough to detect AKI until a significant decline in renal filtration has occurred. Urine neutrophil gelatinase-associated lipocalin (NGAL), part of an acute response to the release of tissue iron from cells, is an early biomarker and a predictor of AKI in a variety of clinical settings. We sought to evaluate the relationship between urine catalytic iron (unbound iron) and NGAL over the course of AKI due to cardiac surgery.
Fourteen patients who underwent open heart surgery had the following measured: serum creatinine (0, 12, 24, 48 and 72 h postoperatively), urine NGAL and urine catalytic iron (0, 8, 24 and 48 h postoperatively). Urine NGAL and urine catalytic iron were quantified by immunoassay and bleomycin-detectable iron assay, respectively. AKI was defined by the Acute Kidney Injury Network (AKIN) criteria.
Urine catalytic iron increased significantly (p < 0.05) within 8 h and peaked at 24 h postoperatively in patients who developed AKI (n = 8, baseline 101.96 ± 177.48, peak 226.35 ± 238.23 nmol/l, p = 0.006), but not in non-AKI patients (n = 6, baseline 131.08 ± 116.21, peak 163.99 ± 109.62 nmol/l, p = 0.380). Urine NGAL levels also peaked at 24 h with significant increase observed only in AKI patients: AKI – baseline 34.88 ± 26.47, peak 65.50 ± 27.03 ng/ml, p = 0.043; non-AKI – baseline 59.33 ± 31.72, peak 71.00 ± 31.76 ng/ml, p = 0.100. The correlation between baseline levels of urine catalytic iron and NGAL and peak levels of urine catalytic iron and NGAL was r = 0.86, p < 0.0001.
Urine catalytic iron appears to rise and fall in concert with NGAL in patients undergoing cardiac surgery and may be indicative of early AKI. Future research into the role that catalytic iron plays in acute organ injury syndromes and its potential diagnostic and therapeutic implications is warranted.
PMCID: PMC3743453  PMID: 23946721
Catalytic iron; Marker; Neutrophil gelatinase-associated lipocalin; Acute kidney injury; Heart surgery
20.  Discovery and validation of cell cycle arrest biomarkers in human acute kidney injury 
Critical Care  2013;17(1):R25.
Acute kidney injury (AKI) can evolve quickly and clinical measures of function often fail to detect AKI at a time when interventions are likely to provide benefit. Identifying early markers of kidney damage has been difficult due to the complex nature of human AKI, in which multiple etiologies exist. The objective of this study was to identify and validate novel biomarkers of AKI.
We performed two multicenter observational studies in critically ill patients at risk for AKI - discovery and validation. The top two markers from discovery were validated in a second study (Sapphire) and compared to a number of previously described biomarkers. In the discovery phase, we enrolled 522 adults in three distinct cohorts including patients with sepsis, shock, major surgery, and trauma and examined over 300 markers. In the Sapphire validation study, we enrolled 744 adult subjects with critical illness and without evidence of AKI at enrollment; the final analysis cohort was a heterogeneous sample of 728 critically ill patients. The primary endpoint was moderate to severe AKI (KDIGO stage 2 to 3) within 12 hours of sample collection.
Moderate to severe AKI occurred in 14% of Sapphire subjects. The two top biomarkers from discovery were validated. Urine insulin-like growth factor-binding protein 7 (IGFBP7) and tissue inhibitor of metalloproteinases-2 (TIMP-2), both inducers of G1 cell cycle arrest, a key mechanism implicated in AKI, together demonstrated an AUC of 0.80 (0.76 and 0.79 alone). Urine [TIMP-2]·[IGFBP7] was significantly superior to all previously described markers of AKI (P <0.002), none of which achieved an AUC >0.72. Furthermore, [TIMP-2]·[IGFBP7] significantly improved risk stratification when added to a nine-variable clinical model when analyzed using Cox proportional hazards model, generalized estimating equation, integrated discrimination improvement or net reclassification improvement. Finally, in sensitivity analyses [TIMP-2]·[IGFBP7] remained significant and superior to all other markers regardless of changes in reference creatinine method.
Two novel markers for AKI have been identified and validated in independent multicenter cohorts. Both markers are superior to existing markers, provide additional information over clinical variables and add mechanistic insight into AKI.
Trial registration number NCT01209169.
PMCID: PMC4057242  PMID: 23388612
21.  Relation Between Body Mass Index, Exercise Training, and Outcomes in Chronic Systolic Heart Failure 
The American journal of cardiology  2011;108(12):1754-1759.
Exercise training (ET) in heart failure (HF), as demonstrated in the HF-ACTION trial, was associated with improved exercise tolerance and health status, and a trend towards reduced mortality or hospitalizations. This analysis of the HF-ACTION cohort examines the effect of ET in overweight and obese compared to normal HF subjects. 2,314 of 2,331 systolic HF subjects randomized to aerobic ET vs. usual care in HF-ACTION were analyzed to determine the effect of ET on all cause mortality, hospitalizations, exercise parameters, quality of life (QOL), and body weight changes by subgroups of body mass index (BMI). Strata included normal weight (BMI 18.5 – 24.9 kg/m2), overweight (BMI 25.0 – 29.9 kg/m2), obese I (BMI 30 – 34.9 kg/m2), obese II (BMI 35-39.9 kg/m2), and obese III (BMI ≥ 40 kg/m2). At enrollment, 19.4% of subjects were normal weight, 31.3% overweight, and 49.4% obese. Higher BMI was associated with a non-significant increase in all cause mortality or hospitalization. ET was associated with non-significant reductions in all cause mortality or hospitalization in each weight category (HR 0.98, 0.95, 0.92, 0.89, and 0.86 in normal weight, overweight, obese I, obese II, and obese III categories, respectively [all p>0.05]). Modeled improvement in exercise capacity (peak oxygen consumption) and QOL in the ET group was seen in all BMI categories. In conclusion, aerobic ET in HF was associated with a non-significant trend towards decreased mortality and hospitalizations and a significant improvement in QOL across the range of BMI categories.
PMCID: PMC3229667  PMID: 21907317
heart failure; body mass index; exercise
22.  Potential Adverse Cardiovascular Effects From Excessive Endurance Exercise 
Mayo Clinic Proceedings  2012;87(6):587-595.
A routine of regular exercise is highly effective for prevention and treatment of many common chronic diseases and improves cardiovascular (CV) health and longevity. However, long-term excessive endurance exercise may induce pathologic structural remodeling of the heart and large arteries. Emerging data suggest that chronic training for and competing in extreme endurance events such as marathons, ultramarathons, ironman distance triathlons, and very long distance bicycle races, can cause transient acute volume overload of the atria and right ventricle, with transient reductions in right ventricular ejection fraction and elevations of cardiac biomarkers, all of which return to normal within 1 week. Over months to years of repetitive injury, this process, in some individuals, may lead to patchy myocardial fibrosis, particularly in the atria, interventricular septum, and right ventricle, creating a substrate for atrial and ventricular arrhythmias. Additionally, long-term excessive sustained exercise may be associated with coronary artery calcification, diastolic dysfunction, and large-artery wall stiffening. However, this concept is still hypothetical and there is some inconsistency in the reported findings. Furthermore, lifelong vigorous exercisers generally have low mortality rates and excellent functional capacity. Notwithstanding, the hypothesis that long-term excessive endurance exercise may induce adverse CV remodeling warrants further investigation to identify at-risk individuals and formulate physical fitness regimens for conferring optimal CV health and longevity.
PMCID: PMC3538475  PMID: 22677079
CAC, coronary artery calcium; CHD, coronary heart disease; CV, cardiovascular; EF, ejection fraction; ET, exercise training; LV, left ventricular; MRI, magnetic resonance imaging; PA, physical activity; RA, right atrium; RV, right ventricular; SCD, sudden cardiac death; VA, ventricular arrhythmia
23.  Dysglycemia but not lipids is associated with abnormal urinary albumin excretion in diabetic kidney disease: a report from the Kidney Early Evaluation Program (KEEP) 
BMC Nephrology  2012;13:104.
The relationship between glycemic control and lipid abnormalities with urinary albumin-creatinine ratio (ACR) in chronic kidney disease (CKD) patients with diabetes mellitus (DM) is unknown. We sought to investigate the association of dyslipidemia and glycemic control with levels of albuminuria in the National Kidney Foundation (NKF) Kidney Early Evaluation Program (KEEP) participants with DM and CKD stage 3 or higher.
We performed a cross-sectional study of 6639 eligible KEEP patients with DM and CKD Stage 3 to 5 from June 2008 to December 2009. Multivariate logistic regression was used to evaluate the association of lipid parameters (per 10 mg/dl change in serum level) and glycosylated hemoglobin (HbA1c) values with three degrees of albuminuria normo (<30 mg⁄g), micro (30 to 300 mg⁄g) and macro (>300 mg⁄g).
2141 KEEP participants were included. HbA1c levels were strongly associated with micro-albuminuria (compared to normo-albuminuria) and macro-albuminuria (compared to normo-albuminuria and micro-albuminuria). Each 1.0% increase in HbA1c increased the odds of micro-albuminuria by 32% (OR 1.32, 95% CI 1.23-1.42) and the odds of macro-albuminuria (vs. microalbuminuria) by 16% (OR 1.16, 95% CI 1.05-1.28). Only increases in serum HDL were associated with decreased odds of micro-albuminuria; otherwise, the association between other components of the serum lipid profile with urinary ACR did not reach statistical significance.
In this cross-sectional study of 2141 KEEP participants with DM and CKD stages 3–5, overall glycemic control but not lipids were associated with abnormal urinary albumin excretion, a marker of increased risk for progressive disease.
PMCID: PMC3480932  PMID: 22958709
Chronic Kidney Disease; Diabetes Mellitus; Proteinuria; Dyslipidemia; Glycosylated hemoglobin
24.  SELDI-TOF-MS Serum Profiling Reveals Predictors of Cardiac MRI Changes in Marathon Runners 
Purpose. To utilize proteomics to discover proteins associated with significant cardiac magnetic resonance imaging (MRI) changes in marathon runners. Methods. Serum from 25 runners was analyzed by surface enhanced laser desorption ionization time-of-flight mass spectrometry (SELDI-TOF-MS). Proteomic profiles were compared in serum samples obtained prior to the race, at the finish line and within 7 hours after race to identify dynamic proteins correlated with cardiac MRI changes. Results. 693 protein/peptide clusters were identified using two ProteinChip surface chemistries and, of these, 116 were significantly different between the three time points. We identified 7 different patterns of protein expression change within the runners and 5 prerace protein peaks, 16 finish-line protein levels, and 15 postrace proteins which were correlated with significant postrace cardiac MRI changes. Conclusions. This study has identified baseline levels of proteins which may be predictive of risk of significant cardiac damage following a marathon race. Preliminary identification of the significant proteins suggested the involvement of cytokines and other proteins involved in stress and inflammatory response.
PMCID: PMC3439948  PMID: 22988506
25.  Blood Pressure Components and End-stage Renal Disease in Persons With Chronic Kidney Disease 
Archives of internal medicine  2012;172(1):41-47.
Treatment of hypertension is difficult in chronic kidney disease (CKD), and blood pressure goals remain controversial. The association between each blood pressure component and end-stage renal disease (ESRD) risk is less well known.
We studied associations of systolic and diastolic blood pressure (SBP and DBP, respectively) and pulse pressure (PP) with ESRD risk among 16 129 Kidney Early Evaluation Program (KEEP) participants with an estimated glomerular filtration rate of 60 mL/min/1.73 m2 using Cox proportional hazards. We estimated the prevalence and characteristics associated with uncontrolled hypertension (SBP≥150 or DBP≥90 mm Hg).
The mean (SD) age of participants was 69 (12) years; 25% were black, 6% were Hispanic, and 43% had diabetes mellitus. Over 2.87 years, there were 320 ESRD events. Higher SBP was associated with higher ESRD risk, starting at SBP of 140 mm Hg or higher. After sex and age adjustment, compared with SBP lower than 130 mm Hg, hazard ratios (HRs) were 1.08 (95% CI, 0.74–1.59) for SBP of 130 to 139 mm Hg, 1.72 (95% CI, 1.21–2.45) for SBP of 140 to 149 mm Hg, and 3.36 (95% CI, 2.51–4.49) for SBP of 150 mm Hg or greater. After full adjustment, HRs for ESRD were 1.27 (95% CI, 0.88–1.83) for SBP of 140 to 149 mm Hg and 1.36 (95% CI, 1.02–1.85) for SBP of 150 mm Hg or higher. Persons with DBP of 90 mm Hg or higher were at higher risk for ESRD compared with persons with DBP of 60 to 74 mm Hg (HR, 1.81; 95% CI, 1.33–2.45). Higher PP was also associated with higher ESRD risk (HR, 1.44 [95% CI, 1.00–2.07] for PP≥80 mm Hg compared with PP<50 mm Hg). Adjustment for SBP attenuated this association. More than 33% of participants had uncontrolled hypertension (SBP≥150 mm Hg or DBP≥90 mm Hg), mostly due to isolated systolic hypertension (54%).
In this large, diverse, community-based sample, we found that high SBP seemed to account for most of the risk of progression to ESRD. This risk started at SBP of 140 mm Hg rather than the currently recommended goal of less than 130 mm Hg, and it was highest among those with SBP of at least 150 mm Hg. Treatment strategies that preferentially lower SBP may be required to improve BP control in CKD.
PMCID: PMC3417125  PMID: 22232147

Results 1-25 (48)