Assessment of cardiac structure and function in kidney failure: understanding echocardiography and magnetic resonance imaging for the nephrologist.

Cardiovascular disease is the leading cause of death in patients with kidney failure or on chronic dialysis. Patients on chronic dialysis have a 10- to 50-fold increased risk of sudden cardiac death compared to patients with normal kidney function. Adverse changes in cardiac structure and function may not manifest with clinical symptoms in patients with kidney failure and, therefore, pose a challenge in identifying cardiac dysfunction early. Fortunately, there are multi-modality cardiac imaging techniques available, including echocardiography and cardiac magnetic resonance imaging, that can help our understanding of the pathophysiology of cardiac dysfunction in kidney failure. This review describes the benefits and limitations of these two commonly available cardiac imaging modalities to assess cardiac structure and function, thereby aiding nephrologists in choosing the most appropriate investigative tool based on individual clinical circumstances. For the purposes of this review, cardiac imaging for detection of coronary artery disease has been omitted.

[Renal failure in the medicolegal evaluation of civil invalidity and social security disability (INPS)].

After a quick description of the anatomopathology and physiopathology of renal failure, the Authors delve into the problem of assessing its medicolegal aspects in the fields of civil invalidity and social security. In Italy, civil invalidity involves protecting the psychological and physical welfare of the disabled, as sanctioned by law 118 of 1971; this law protects all citizens with a debilitating condition, including those who do not work or are not of working age. A disabled person is someone who, if of working age (between 18 and retirement) has a reduction of more than ⅓ (34%) of their general work capacity; if under or over the retirement age, they have a persistent difficulty in carrying out age-appropriate functions and tasks. In support of an application for being awarded civil invalidity, people can also refer to law no. 104 of 1992, which assesses social, relational and work disadvantages of a disabled person. INPS (Italian Social Security Institute) protection, on the other hand, is a social security protection based on health requirements (having a capacity for work which is reduced by more than ⅓, as established by law no. 222 of 1984), as well as on the following administrative requirement: having paid, as a worker, at least 260 weekly contributions, equivalent to five years of contribution and insurance, of which 156, equal to three years of contribution and insurance, were made in the five-year period preceding the date of submitting the application. If this is the case, the protected person, thus insured, can enjoy protection for their illness by virtue of the stipulations for social security.

Assessment of postoperative renal function after adrenalectomy in patients with primary aldosteronism.

OBJECTIVE: To investigate kidney function change during adrenalectomy in patients with primary aldosteronism and assess predictors of kidney function decline. METHODS: The present study included 90 patients who underwent adrenalectomy for primary aldosteronism between 2004 and 2017. Kidney function was evaluated 1 month after surgery. Predictors associated with a ≥10% decline in the estimated glomerular filtration rate were investigated. Kidney parenchymal volume was compared before and after surgery in 10 patients using volumetric studies. RESULTS: The mean estimated glomerular filtration rate decline in the total cohort at 1 month after surgery was 13.3% (before: 72.9 mL/min/1.73 m2 , after: 64.9 mL/min/1.73 m2 , P < 0.0001). The mean serum plasma aldosterone concentration (before: 373 pg/mL vs after: 78 pg/mL, P < 0.0001) and potassium level (before: 3.7 mEq/L vs after: 3.9 mEq/L, P = 0.0001) were also significantly different after surgery. Age (odds ratio 6.37, P = 0.0006), preoperative plasma aldosterone concentration (odds ratio 3.12, P = 0.0209) and preoperative serum potassium level (odds ratio 2.87, P = 0.0010) were independent predictors of a ≥10% decline in estimated glomerular filtration rate. Volumetric studies in 10 patients showed that mean postoperative parenchymal volume was significantly decreased compared with the preoperative volume (263 cc vs 312 cc, P = 0.0003), with decreases in estimated glomerular filtration rate from 63 to 56 mL/min/1.73 m2 (P = 0.0146). CONCLUSIONS: Kidney function deterioration after adrenalectomy can be detected in patients with primary aldosteronism. Age, preoperative plasma aldosterone concentration and preoperative potassium level are significant predictors of a decrease in the estimated glomerular filtration rate. Normal parenchymal volume decreases in line with renal functional deterioration.

Assessment of the Effects of Age and Renal Function on Pharmacokinetics of Bazedoxifene in Postmenopausal Women.

Bazedoxifene (BZA), a chemically distinct selective estrogen receptor modulator, has demonstrated efficacy and long-term safety in phase 3 placebo-controlled studies for prevention and treatment of osteoporosis. Here, we assessed the potential effects of age and renal function on BZA pharmacokinetics in healthy postmenopausal women (aged 55-84 years; CLcr, 32-109 mL/min). This was an open-label, single-dose, parallel, nonrandomized inpatient study conducted in healthy postmenopausal women and postmenopausal women with impaired renal function. Each subject received a single oral dose of BZA in a 20-mg tablet. Twenty-six subjects were enrolled: 8 in each of 3 age groups (55-64 years, 65-74 years, ≥75 years) and 2 (aged 71 and 75 years) with mild renal impairment; all subjects received treatment and completed the study. Age-related changes in pharmacokinetics were apparent. Although the correlation was modest (R2 = 0.28), BZA CL/F decreased steadily with age, such that the oldest group (>75 years) had a mean CL/F 60% less than the youngest group (55-64 years). Over the observed range of CLcr, there was a weak positive correlation (R2 = 0.19) between BZA CL/F and CLcr.

Predicting timing of clinical outcomes in patients with chronic kidney disease and severely decreased glomerular filtration rate.

Patients with chronic kidney disease and severely decreased glomerular filtration rate (GFR) are at high risk for kidney failure, cardiovascular disease (CVD) and death. Accurate estimates of risk and timing of these clinical outcomes could guide patient counseling and therapy. Therefore, we developed models using data of 264,296 individuals in 30 countries participating in the international Chronic Kidney Disease Prognosis Consortium with estimated GFR (eGFR)s under 30 ml/min/1.73m2. Median participant eGFR and urine albumin-to-creatinine ratio were 24 ml/min/1.73m2 and 168 mg/g, respectively. Using competing-risk regression, random-effect meta-analysis, and Markov processes with Monte Carlo simulations, we developed two- and four-year models of the probability and timing of kidney failure requiring kidney replacement therapy (KRT), a non-fatal CVD event, and death according to age, sex, race, eGFR, albumin-to-creatinine ratio, systolic blood pressure, smoking status, diabetes mellitus, and history of CVD. Hypothetically applied to a 60-year-old white male with a history of CVD, a systolic blood pressure of 140 mmHg, an eGFR of 25 ml/min/1.73m2 and a urine albumin-to-creatinine ratio of 1000 mg/g, the four-year model predicted a 17% chance of survival after KRT, a 17% chance of survival after a CVD event, a 4% chance of survival after both, and a 28% chance of death (9% as a first event, and 19% after another CVD event or KRT). Risk predictions for KRT showed good overall agreement with the published kidney failure risk equation, and both models were well calibrated with observed risk. Thus, commonly-measured clinical characteristics can predict the timing and occurrence of clinical outcomes in patients with severely decreased GFR.

Characterization of Mineralocorticoid Receptor Antagonist Therapy Initiation in High-Risk Patients With Heart Failure.

BACKGROUND: Heart failure guidelines recommend routine monitoring of serum potassium, and renal function in patients treated with a mineralocorticoid receptor antagonist (MRA). How these recommendations are implemented in high-risk patients or according to setting of drug initiation is poorly characterized. METHODS AND RESULTS: We conducted a retrospective cohort study of Medicare beneficiaries linked to laboratory data in 10 states with prevalent heart failure as of July 1, 2011, and incident MRA use between May 1 and September 30, 2011. Outcomes included laboratory testing before MRA initiation and in the early (days 1-10) and extended (days 11-90) post-initiation periods, based on setting of drug initiation and the presence of renal insufficiency. Additional outcomes included abnormal laboratory results and adverse events proximate to MRA initiation. Of 10 443 Medicare beneficiaries with heart failure started on an MRA, 19.7% were initiated during a hospitalization. Appropriate follow-up laboratory testing across all time periods occurred in 25.2% of patients with inpatient initiation compared with 2.8% of patients begun as an outpatient. Patients with chronic kidney disease had higher rates of both hyperkalemia and acute kidney failure in the early (1.3% and 2.7%, respectively) and extended (5.6% and 9.8%, respectively) post-initiation periods compared with those without chronic kidney disease. CONCLUSIONS: Patients initiated on MRA therapy as an outpatient had extremely poor rates of guideline indicated follow-up laboratory monitoring after drug initiation. In particular, patients with chronic kidney disease are at high risk for adverse events after MRA initiation. Quality improvement initiatives focused on systems to improve appropriate laboratory monitoring are needed.

Assessment of DCE-MRI parameters for brain tumors through implementation of physiologically-based pharmacokinetic model approaches for Gd-DOTA.

Dynamic-contrast enhanced magnetic resonance imaging (DCE-MRI) is used for detailed characterization of pathology of lesions sites, such as brain tumors, by quantitative analysis of tracer's data through the use of pharmacokinetic (PK) models. A key component for PK models in DCE-MRI is the estimation of the concentration-time profile of the tracer in a nearby vessel, referred as Arterial Input Function (AIF). The aim of this work was to assess through full body physiologically-based pharmacokinetic (PBPK) model approaches the PK profile of gadoteric acid (Gd-DOTA) and explore potential application for parameter estimation in DCE-MRI based on PBPK-derived AIFs. The PBPK simulations were generated through Simcyp(®) platform and the predicted PK parameters for Gd-DOTA were compared with available clinical data regarding healthy volunteers and renal impairment patients. The assessment of DCE-MRI parameters was implemented by utilizing similar virtual profiles based on gender, age and weight to clinical profiles of patients diagnosed with glioblastoma multiforme. The PBPK-derived AIFs were then used to compute DCE-MRI parameters through the Extended Tofts Model and compared with the corresponding ones derived from image-based AIF computation. The comparison involved: (i) image measured AIF of patients vs AIF of in silico profile, and, (ii) population average AIF vs in silico mean AIFs. The results indicate that PBPK-derived AIFs allowed the estimation of comparable imaging biomarkers with those calculated from typical DCE-MRI image analysis. The incorporation of PBPK models and potential utilization of in silico profiles to real patient data, can provide new perspectives in DCE-MRI parameter estimation and data analysis.

Drug therapy management in patients with renal impairment: how to use creatinine-based formulas in clinical practice.

PURPOSE: The use of estimated glomerular filtration rate (eGFR) in daily clinical practice. METHODS: eGFR is a key component in drug therapy management (DTM) in patients with renal impairment. eGFR is routinely reported by laboratories whenever a serum creatinine testing is ordered. In this paper, we will discuss how to use eGFR knowing the limitations of serum creatinine-based formulas. RESULTS: Before starting a renally excreted drug, an equally effective drug which can be used more safely in patients with renal impairment should be considered. If a renally excreted drug is needed, the reliability of the eGFR should be assessed and when needed, a 24-h urine creatinine clearance collection should be performed. After achieving the best approximation of the true GFR, we suggest a gradual drug dose adaptation according to the renal function. A different approach for drugs with a narrow therapeutic window (NTW) is recommended compared to drugs with a broad therapeutic window. For practical purposes, a therapeutic window of 5 or less was defined as a NTW and a list of NTW drugs is presented. Considerations about the drug dose may be different at the start of the therapy or during the therapy and depending on the indication. Monitoring effectiveness and adverse drug reactions are important, especially for NTW drugs. Dose adjustment should be based on an ongoing assessment of clinical status and risk versus the benefit of the used regimen. CONCLUSION: When determining the most appropriate dosing regimen serum creatinine-based formulas should never be used naively but always in combination with clinical and pharmacological assessment of the individual patient.

Discordance Between Hemoconcentration and Clinical Assessment of Decongestion in Acute Heart Failure.

INTRODUCTION: Hemoconcentration has been proposed as a surrogate for successful decongestion in acute heart failure (AHF). The aim of the present study was to evaluate the relationship between hemoconcentration and clinical measures of congestion. METHODS AND RESULTS: We studied 704 patients with AHF and volume overload. A composite congestion score was calculated at admission and discharge, with a score >1 denoting persistent congestion. Hemoconcentration was defined as any increase in hematocrit and hemoglobin levels between baseline and discharge. Of 276 patient with hemoconcentration, 66 (23.9%) had persistent congestion. Conversely, of 428 patients without hemoconcentration, 304 (71.0%) had no clinical evidence of congestion. Mean hematocrit changes were similar with and without persistent congestion (0.18 ± 3.4% and -0.19 ± 3.6%, respectively; P = .17). There was no correlation between the decline in congestion score and the change in hematocrit (P = .93). Hemoconcentration predicted lower mortality (hazard ratio 0.70, 95% confidence interval 0.54-0.90; P = .006). Persistent congestion was associated with increased mortality independent of hemoconcentration (Ptrend = .0003 for increasing levels of congestion score). CONCLUSIONS: Hemoconcentration is weakly related to congestion as assessed clinically. Persistent congestion at discharge is associated with increased mortality regardless of hemoconcentration. Hemoconcentration is associated with better outcome but cannot substitute for clinically derived estimates of congestion to determine whether decongestion has been achieved.

[New tools for the management of renal function in the elderly: Berlin Initiative Study equation and hematocrit, urea and gender formulae]. / Nuevas herramientas para abordar la función renal en ancianos: la ecuación Berlin Initiative Study y la fórmula hematocrito, urea y género.

In the last few years a debate has emerged on the range of normal renal function in the elderly, and if every elderly person with a glomerular filtration rate estimated using formulas (Cockroft-Gault, MDRD, CKD-EPI) of less than 60ml/min/1.73m(2) has kidney disease. In this review we analysed, based on the results of the study Elderly people with chronic kidney disease of the Hospital de Segovia, the new equations to measure kidney function in the elderly: the Berlin Initiative Study equation designed to estimate the glomerular filtration rate in people aged 70 or more, and the hematocrit, urea and gender formula to establish whether an elderly person with a glomerular filtration rate lower than 60mL/min/1.73m(2) has kidney disease.

Comparison of single CT scan assessment of bone mineral density, vascular calcification and fat mass with standard clinical measurements in renal transplant subjects: the ABC HeART study.

BACKGROUND: Despite limitations of routine methods, Clinical Practice Guidelines support the assessment of bone mineral density (BMD) and vascular calcification in renal transplant recipients. Changes in fat mass also occur post-transplantation, although they are traditionally difficult to measure accurately. We report the feasibility, convenience and accuracy of measuring the above 3 parameters using a novel CT protocol. METHODS: We conducted a cross-sectional study of 64 first renal allograft recipients (eGFR > 30 ml/min/1.73 m(2)). Quantitative CT (QCT) BMD analysis was conducted using CT lumbar spine (GE Medical Systems Lightspeed VCT & Mindways QCT Pro Bone Mineral Densitometry System Version 4.2.3) to calculate spinal volumetric BMD and compared with standard DXA calculated areal BMD at the spine, hip and distal forearm. Abdominal aortic calcification was assessed by semi-quantitative Aortic Calcification Index (ACI) method and compared with lateral lumbar x-ray Kappuila score and pulse wave velocity (PWV). Visceral and subcutaneous adipose tissue volume (Osirix 16 Ver 3.7.1) was compared with BMI. RESULTS: Participants were 61 % male, had a mean age of 47 years, median ESKD duration of 5.4 years and a mean eGFR of 54 ml/min. iDXA median T-score at proximal femur was -1.2 and at lumbar spine was -0.2. Median QCT Trabecular T-score at lumbar spine was -1.2. The percent of subjects with a T-score of < 2.5 by site and method was DXA Proximal Femur: 7 %, DXA distal radius: 17 %, DXA spine: 9 %, QCT (American College of Radiology cutoffs): 9 %. CT derived ACI correlated with PWV (r = 0.29, p = 0.02), pulse wave pressure (r = 0.51, p < 0.001), QCT Trabecular (-0.31, p = 0.01) and cortical volumetric BMD and history of cardiovascular events (Mann-Whitney U, p = 0.02). Both visceral and subcutaneous adipose tissue correlated with BMI (r = 0.63 & 0.64, p < 0.001). CONCLUSIONS: Single CT scan triple assessment of BMD, vascular calcification and body composition is an efficient, accurate and convenient method of risk factor monitoring post renal transplantation.

Kidney function changes with aging in adults: comparison between cross-sectional and longitudinal data analyses in renal function assessment.

The study evaluated whether the renal function decline rate per year with age in adults varies based on two primary statistical analyses: cross-section (CS), using one observation per subject, and longitudinal (LT), using multiple observations per subject over time. A total of 16628 records (3946 subjects; age range 30-92 years) of creatinine clearance and relevant demographic data were used. On average, four samples per subject were collected for up to 2364 days (mean: 793 days). A simple linear regression and random coefficient models were selected for CS and LT analyses, respectively. The renal function decline rates per year were 1.33 and 0.95 ml/min/year for CS and LT analyses, respectively, and were slower when the repeated individual measurements were considered. The study confirms that rates are different based on statistical analyses, and that a statistically robust longitudinal model with a proper sampling design provides reliable individual as well as population estimates of the renal function decline rates per year with age in adults. In conclusion, our findings indicated that one should be cautious in interpreting the renal function decline rate with aging information because its estimation was highly dependent on the statistical analyses. From our analyses, a population longitudinal analysis (e.g. random coefficient model) is recommended if individualization is critical, such as a dose adjustment based on renal function during a chronic therapy.

Astaxanthin from shrimp by-products ameliorates nephropathy in diabetic rats.

AIM: This study investigated the hypoglycemic and antioxidant effects of shrimp astaxanthin on the kidney of alloxan-induced diabetic rats. METHODS: Animals were distributed into four groups of six rats each: a control group (C), a diabetic group (D), a diabetic group supplemented with Astaxanthin (D+As) dissolved in olive oil and a diabetic group supplemented with olive oil (D+OO). In vitro antidiabetic effect was tested in plasma and kidney tissue. RESULTS: The group D of rats showed significant (P < 0.05) increase of glycemia, creatinine, urea and uric acid levels compared to those of the control group (C). Moreover, plasma and kidney malondialdehyde (MDA) and protein carbonyl (PCO) levels for the rats of the group D were significantly increased compared to the control group. Contrariwise, antioxidant enzyme activities, such as catalase (EC 1.11.1.6), superoxide dismutase (EC 1.15.1.1) and non-enzymatic levels of reduced glutathione, were significantly (P < 0.05) decreased in the plasma and kidney of diabetic rats compared to the control ones. The astaxanthin supplementation in rats diet improved the antioxidant enzyme activities and significantly decreased the MDA and PCO levels compared to diabetic rats. Indeed, no significant (P ≥ 0.05) improvement was observed for the fourth group (D+OO) compared to the control group (C). Histological analysis of kidney showed glomerular hypertrophy and tubular dilatation for the diabetic rats. For D+As rats, these histopathological changes were less prominent. CONCLUSIONS: Our results suggest that shrimp astaxanthin may play an important role in reduction of oxidative damage and could prevent pathological changes in diabetic rats suggesting promising application of shrimp astaxanthin in diabet treatment.

The body composition and excretory burden of lean, obese, and severely obese individuals has implications for the assessment of chronic kidney disease.

Obesity could affect associations between creatinine generation, estimated body surface area, and excretory burden, with effects on chronic kidney disease assessment. We therefore examined the impact of obesity on the performances of estimated glomerular filtration rate (eGFR), the urine albumin:creatinine ratio (ACR), and excretory burden in 3611 participants of the Chronic Renal Insufficiency Cohort. Urine creatinine excretion significantly increased with body mass index (BMI) (34 and 31% greater at 40 kg/m(2) or more versus the normal of 18.5-25 kg/m(2)) in men and women, respectively, such that patients with a normal BMI and an ACR of 30 mg/g had the same 24-h albuminuria as severely obese patients with ACR 23 mg/g. The bias of eGFR (referenced to body surface area-indexed iothalamate (i-)GFR) had a U-shaped relationship to obesity in men but progressively increased in women. Nevertheless, obesity-associated body surface area increases were accompanied by a greater absolute (non-indexed) iGFR for a given eGFR, particularly in men. Two men with eGFRs of 45 ml/min per 1.73 m(2), height 1.76 m, and BMI 22 or 45 kg/m(2) had absolute iGFRs of 46 and 62 ml/min, respectively. The excretory burden, assessed as urine urea nitrogen and estimated dietary phosphorus, sodium, and potassium intakes, also increased in obesity. However, obese men had lower odds of anemia, hyperkalemia, and hyperphosphatemia. Thus, for a given ACR and eGFR, obese individuals have greater albuminuria, absolute GFR, and excretory burden. This has implications for chronic kidney disease management, screening, and research.

[Role of renal dysfunction and multifocal atherosclerosis in assessment of prognosis of patients presenting with ST-elevation acute coronary syndrome].

AIM: To assess incidence and severity of renal dysfunction as well as its prognostic value in patients with ST elevation myocardial infarction (STEMI) and multifocal atherosclerosis (MFA). MATERIAL AND METHODS: We enrolled in this study 529 patients with STEMI in whom we estimated creatinine clearance rate (eGFR) and glomerular filtration rate (eCrCl) using Cockcroft-Gault equation and Modification of Diet in Renal Disease (MDRD) formula, respectively. Duplex ultrasonography of lower extremity and extracranial arteries was performed in 423 patients on day 5-10 of hospitalization. Signs of MFA were found in 95% of patients. Hospital mortality was 10.9%. One year survival of 397 patients was assessed by the telephone contacts. Thirty nine patients (9.8%) died. RESULTS: GFR in 35.5% of patients was 30-60, and in 4.9% - less than 30 ml/min/1.73 m2. At the same time 29.5% of patients had CCr 30 - 60, and 3.0% - less than 30 ml/min. Progressive decreases of eCCr and eGFR were observed in patients with incipient MFA (stenosis <30%); relationship between MFA and eGRF was more close. Presence of renal dysfunction in patients with STEACS and MFA was associated elevation of both hospital and 1 year mortality. CONCLUSION: Any manifestation of peripheral atherosclerosis and impairment of renal function should be considered as independent predictors of cardiovascular events in patients after STEMI.

Downstream complications following urinary diversion.

PURPOSE: Surveillance following urinary diversion should be tailored to capture complications downstream from the initial reconstruction. Most analyses of the morbidity associated with urinary diversion are restricted to the index admission or the immediate postoperative period. We characterize the long-term medical and surgical complications and burden of health care use after urinary diversion. MATERIALS AND METHODS: Using the 5% Medicare sample from 1998 to 2005 we identified individuals who underwent cutaneous and orthotopic continent urinary diversion, ileal conduit or other types of diversion including enterocystoplasty from physician claims for the index admission. We restricted our sample to subjects with claims 1 year before surgery and at least 2 years after the diversion. We included benign and malignant primary diagnoses, and evaluated the incidence of medical and surgical complications 2 and 5 years after surgery. We stratified complications by diversion type and compared long-term complications after urinary diversion surgery. RESULTS: Of the 1,565 subjects identified 80% underwent ileal conduit urinary diversion, 7% underwent cutaneous or orthotopic continent diversion and 13% underwent other types of reconstruction. Urinary stone formation, wound complications and fistula complications were more common following continent diversion 5 years after surgery, while ureteral obstruction and renal failure/impairment were more common after ileal conduit diversion. Overall we estimated that more than 16% of patients experienced renal failure or impairment after urinary diversion. CONCLUSIONS: Complications are common after urinary diversion and continue to occur through 5 years postoperatively. Urolithiasis and delayed wound complications appear to occur more commonly after continent diversion than after other urinary diversions. A large proportion of patients experience renal deterioration after diversion. These results highlight the need to survey patients for the diversion related complications of cystectomy as rigorously as we monitor for cancer recurrence.

Concordance of estimated glomerular filtration rates using Cockcroft-Gault modification of diet in renal disease, and chronic kidney disease epidemiology in renal transplant recipients.

INTRODUCTION: Various equations have been used to estimate the glomerular filtration rate (GFR) in renal patients, including kidney transplant recipients. Controversy exists concerning which equation is more precise to determine kidney failure. AIM: The aim of this study was to analyze the concordance (bias, variability, and exactness) of GFR estimated by the Modification of Diet in Renal Disease (MDRD4) and the Chronic Kidney Disease Epidemiology (CKD-EPI) equations using the Cockcroft-Gault (CG) method as the reference. MATERIAL AND METHODS: This observational, cross-sectional study included 153 clinically stable patients who underwent kidney transplantation between 2007 and 2009. The GFR was estimated at 12 months after the transplantation using the MDRD and CKP-EPI formula, using CG as the reference. RESULTS: The mean GFR for the various methods was as follows: CG = 65.6 ± 23.3 mL/min/1.73 m(2), MDRD4 = 54.9 ± 19.3 mL/min/1.73 m(2), and CKD-EPI = 55.8 ± 19.6 mL/min/1.73 m(2). Good correlations were found between CG-MDRD4 (r = 0.84; P < .001), CG-CKD-EPI (r = 0.87; P < .001), and MDRD4-CKD-EPI (r = 0.98; P < .001). The analysis of concordance detected a bias (normal difference) of -10.6 ± 12.7 versus -9.8 ± 11.3 mL/min/1.73 m(2) (P = .006), a variability (percent difference) of 14.5 ± 15.4% versus 13.6 ± 14.5% (P = .031), and an exactness (P30) of 81.7% versus 86.9% (P < .001) of CG-MDRD4 versus CG-CKD-EPI, respectively. For a GFR >60 mL/min/1.73 m(2) the exactness was 75.3% versus 83.5% (P < .001) for CG-MDRD4 versus CG-CKD-EPI, and for a GFR ≤ 60 mL/min/1.73 m(2) it was 89.7% versus 91.2% (P < .001). CONCLUSIONS: In our population the CKD-EPI method most approached the CG values, particularly when the GFR was >60 mL/min/1.73 m(2).