Modification Of Diet In Renal Disease Study Research Articles

MDRD is the eGFR equation most strongly associated with 4-year mortality among patients with diabetes in Colombia

IntroductionWe compared the association of glomerular filtration rate (GFR) estimated with the Cockcroft-Gault, Modification of Diet in Renal Disease study (MDRD), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), or the new...

The role of blood pressure control in the prevention of cardiorenal disease in patients with chronic kidney disease.

Optimal blood pressure (BP) control has been debated between two schools of thought: standard BP control to a goal of systolic BP (SBP) <140 mmHg and intensive BP control with a goal of <120 mmHg. Currently only three randomized controlled trials (RCTs) have been performed to address this question, which will be included in this review: the Action to Control Cardiovascular Risk in Diabetes (ACCORD) Study Group (2010), the Systolic Blood Pressure Intervention Trial (SPRINT; 2015) and the Strategy of Blood Pressure Intervention in the Elderly Hypertensive Patients (STEP) trial, performed in Chinese participants in 2021 [1–3]. Further insights into BP management to prevent cardiovascular disease (CVD) events in patients with chronic kidney disease (CKD) will also be reviewed here. Unfortunately, there is less data from RCTs for determining optimal BP levels to prevent renal disease progression. Only three studies in non-diabetic CKD—SPRINT, the Modification of Diet in Renal Disease (MDRD) study and the African American Study of Kidney Disease and Hypertension (AASK)—and no studies in patients with CKD due to type 2 diabetes mellitus (T2DM) have been performed to investigate this problem and, to date, the ideal management protocol for clinicians is lacking. In this review we will also include investigations from historically important studies focusing on control of BP and its effects in patients with CKD, including the MDRD study (1993), the AASK study (2001) and the Ramipril Efficacy In Nephropathy 2 (REIN-2) study (2005) [4–6]. The study of CKD patients in the SPRINT study [7] also provides an important perspective on the importance of more intensive BP control on cardiovascular events. It is also important to note that despite the same body of evidence from these clinical studies, guideline committees have come up with different recommendations for target BP, further complicating the question of optimal BP targets. This opinion paper is targeted towards NDT readers with an interest in kidney disease in relation to BP goals and cardiovascular outcomes.

Implications of the 2021 CKD-EPI cystatin C/creatinine eGFR equation for eligibility for therapy in HFrEF: insights from PARADIGM-HF

Abstract Background Estimated glomerular filtration rate (eGFR) is a key determinant of eligibility for many life-saving therapies in HFrEF. Recently, the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) provided new equations based on creatinine (CKD-EPIcr), cystatin C (CKD-EPIcys) or both (CKD-EPIcyscr) that do not include race. These new equations may reclassify individuals, irrespective of race, from one eGFR category to another, with implications for eligibility for HFrEF treatments. Purpose To assess the difference between eGFR estimation using the 2021 CKD-EPIcyscr equation and the 2009 CKD-EPIcr and Modification of Diet in Renal Disease Study (MDRD)-4 equations which are still standard in many European laboratories. Methods We included patients from PARADIGM-HF with cystatin C and creatinine values available at the time of randomization. For each patient, baseline eGFRs were calculated using the 3 equations described. Our focus was on patients with chronic kidney disease (CKD) stages III–V. Results Overall, 1910 patients were eligible. Mean age was 67.3 (10.1) year and 385 (18.7%) were female. Using 2009 CKD-EPIcr, 779 patients were in CKD stages 3–5, of which 233 (30%) were reclassified to a better CKD stage (higher eGFR) with the 2021 CKD-EPIcyscr equation (Table 1). Similar reclassification was seen when comparing MDRD-4 with the 2021 CKD-EPIcyscr equation: 277 (33%) of 831 patients in CKD stages 3–5 were reclassified to a better CKD stage (Figure 1). Conclusions The 2021 CKD-EPIcyscr equation favourably reclassified CKD stage in a large percentage of patients with HFrEF and a low eGFR, potentially increasing the proportion of these patients considered eligible for guideline-recommended therapies. Funding Acknowledgement Type of funding sources: None.

Alterations in Glomerular Filtration Rates Using Different Algorithms in the Korean Population Visiting Local Clinics and Hospitals.

We retrospectively reviewed the estimated glomerular filtration rates (eGFR) calculated by three equations: (1) Modification of Diet in Renal Disease Study (MDRD), (2) Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) using serum creatinine in 2009 (CKD-EPI 2009), and (3) CKD-EPI suggested in 2021 (CKD-EPI 2021), in an adult Korean population visiting local clinics and hospitals for health check-ups between 2019 and 2021 to investigate the effect of changes in the prevalence of chronic kidney diseases using those equations. During the study period, serum creatinine tests were performed on 442,566 subjects (205,236 men and 237,330 women). The overall prevalence rates of decreased eGFR (<60 mL/min/1.73 m2) at baseline measurement were as follows: 3.4% using MDRD, 2.8% using CKD-EPI 2009, and 2.1% using CKD-EPI 2021. The prevalence of decreased eGFR increased with age. Among 442,566 tests, specimens having simultaneously measured random urine dipstick tests for proteinuria represented 6.0% of the population, and the albumin-creatinine ratio (ACR) was 0.3%. The prevalence of specimens having both decreased eGFR and proteinuria was significantly different among equations (p < 0.05). Among the three equations, MDRD and CKD-EPI 2009 had a similar specimen prevalence of decreased eGFR and proteinuria (≥1+) using a dipstick test or albuminuria (urine ACR > 30 mg/g creatinine), while those based on CKD-EPI 2021 were about half of those based on MDRD and CKD-EPI 2009. Future studies are needed to clarify the clinical impact of the changes in the calculations for eGFR.

An Endorsement of the Removal of Race From GFR Estimation Equations: A Position Statement From the National Kidney Foundation Kidney Disease Outcomes Quality Initiative

An Endorsement of the Removal of Race From GFR Estimation Equations: A Position Statement From the National Kidney Foundation Kidney Disease Outcomes Quality Initiative

Avaliação dos preditores da falha dos antivirais de ação direta como mais um passo para programas de eliminação de VHC mais eficiente: o polimorfismo genético IL28B (IFNL4) não tem destaque, enquanto maior liberação estimada do “clearence” de creatinina é um fator esquecido

ABSTRACT Background: Sustained virologic response (SVR) rates after directly acting antivirals (DAAs) for hepatitis C virus (HCV) exceed 95%. This encouraged policymakers to put plans to achieve HCV elimination by 2030. The remaining percentage of non-SVR12 can affect HCV eradication strategies in the real-world especially the compliance of large numbers of treated persons to follow up for assessment of virologic response cannot be guaranteed. Objective: We aimed to assess predictors of failure to achieve SVR after receiving sofosbuvir plus NS5A inhibitor as an important step towards achieving better HCV eradication strategies. Methods: During the period from 1st November 2018 to 1st November 2019, 1581 treatment-naive patients received sofosbuvir plus daclatasvir ± ribavirin at our unit and 10 patients were referred to us with HCV relapse after the same regimens. A total of 163 out of the 1581 patients were lost for follow-up before assessment of virologic response and excluded from the analysis. 20 out of the remaining patients failed to achieve SVR12. Data from the 30 patients with non-SVR12 were included in the case-control analysis. Results: Every unit increase in estimated creatinine clearance using modification of diet in renal disease study (MDRD) score, total bilirubin, and INR was associated with 1.03, 13.92, and 80.08 times greater odds of non-SVR12 (P&lt;0.001, P=0.0016, P=0.02) respectively. The presence of liver cirrhosis on ultrasonography increases the odds by 10.03. (P=0.009). Conclusion: Higher MDRD score, INR, total bilirubin, and presence of sonographic features of liver cirrhosis are predictors of failure to achieve SVR12 using sofosbuvir plus NS5A inhibitor.

Evaluation of Long-Term Kidney Function Following Orthotopic Heart Transplantation

Acute impairment of kidney function in patients with heart failure and heart transplantation is a frequent condition. However, the impact of the transplant on long-term kidney function remains controversial. This study describes a cohort of patients who received a heart transplant in a reference hospital between 2005 and 2019. Glomerular filtration rate during follow-up was calculated at 0, 6,12, 24, and 60 months using the Cockcroft-Gault and MDRD (modification of diet in renal disease study) equations. To identify changes we compared glomerular filtration rate (GFR) at baseline with measurements over time after heart transplantation, using a paired t test and a longitudinal model of Generalized Estimating Equations (GEE). Forty-four patients were included. The mean of baseline GFR was 67.9 ± 1.3 mL/min. A triple immunosuppressive therapy scheme was used with cyclosporine/tacrolimus, mycophenolate mofetil, and steroid, with progressive dose reduction. After adjusting for multiple variables, we found no reduction of GFR over time with the GEE model. There was no significant difference in GFR using Cockcroft-Gault equation at 6 (mean difference [MD] 4.46; confidence interval [CI] -2.1 to 11.09; P=0.18), 12 (MD 1.65, CI -4.5 to 7.82; P=0.59), 36 (MD 0.69; CI -6.04 to 7.43; P=0.83), and 60 months (MD 0.62; CI -5.5 to 6.79; P=0.83). Similar findings were found using MDRD equation. There is no significant GFR decline between the time of heart transplantation and a follow-up at 60 months. New studies are needed to evaluate changes in renal function beyond this timeframe.

Kidney function and daily emtricitabine/tenofovir disoproxil fumarate pre-exposure prophylaxis against HIV: results from the real-life multicentric demonstrative project PrEP Brazil

BackgroundPre-Exposure Prophylaxis (PrEP) has demonstrated efficacy in the reduction of sexually transmitted HIV infections. The prolonged use of tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC) co-formulation (TDF/FTC), however, may result in augmented risk of renal toxicity. We aimed to evaluate changes in the estimated Glomerular Filtration Rate (eGFR) in a real-world population setting of participants enrolled in PrEP Brazil, a 48-week prospective, open-label, demonstration study to assess the feasibility of daily oral TDF/FTC used by men who have sex with men and transgender women at high-risk of HIV infection, all over 18 years old.MethodsKidney function was assessed by serial measurement of serum creatinine and eGFR with the Modification of Diet in Renal Disease Study (MDRD) formula on weeks 4, 12, 24, 36 and 48. Adherence to PrEP was assessed by dosing TDF concentration in dried blood spots at weeks 4 and 48, measured by liquid chromatography-mass spectrometry or mass spectrometry.ResultsOf 392 participants completing the 48-week follow-up protocol with TDF blood detectable levels and eGFR measures, 43.1% were young adults, of Caucasian ethnic background (57.9%), with BMI below 30 kg/m2, without arterial hypertension. At screening, median eGFR was 93.0 mL/min/1.73 m2. At week 4 follow-up, 90 (23% of the study population) participants presented reductions in eGFR greater than 10 mL/min/1.73 m2 as compared to baseline eGFR, some as large as 59 mL/min/1.73 m2, but with no clinical outcomes (adverse events and renal adverse events) severe enough to demand TDF/FTC discontinuation. A negative relationship was observed between TDF blood levels and eGFR at weeks 4 (r = − 0.005; p < 0.01) and 48 (r = − 0.006; p < 0.01).ConclusionsThese results suggest that the renal function profile in individuals on TDF/FTC may be assessed on week 4 and then only annually, allowing a more flexible medical follow-up in primary care centers.

In-hospital complications in acute ST-elevation myocardial infarction depending on renal function.

To analyze in-hospital complications in patients with acute ST-elevation myocardial infarction (STEMI) depending on renal function. Observational study in patients with STEMI. The study included 169patients undergoing primary percutaneous coronary intervention. In all patients glomerular filtration rate (GRF) was calculated using the Modification of Diet in Renal Disease Study (MDRD) equation. Of these patients, 84had aGFR ≥ 90 ml/min/1.73 m2 (Group1) and 85 < 90 ml/min/1.73 m2 (Group2). Other parameters in both groups were comparable. Study groups were followed to compare Killip class > 2acute heart failure, in-hospital pneumonia, pulseless ventricular tachycardia or ventricular fibrillation, new onset atrial fibrillation, and high grade atrioventricular block. All patients were treated according to European Society of Cardiology (ESC) guidelines for the management of acute myocardial infarction in patients presenting with ST elevation. Mean GFR in Group1 was 107.6 [Formula: see text] and in Group2 75.3 [Formula: see text] 11.2 (p < 0.0001). The incidence of atrial fibrillation was higher in Group2: in Group1 and Group2 the atrial fibrillation rate was 1.12% (one of 84) vs 8.24% (seven of 85) (p = 0.031), respectively. Group1 revealed significantly lower rates of acute heart failure (Killip class > 2): in Group1 and Group2 0% (0of 84patients) vs 5.88% (five of 85patients) (p = 0.024), respectively. The authors found no significant differences for other complications: in Group1 and Group2 ventricular tachycardia or ventricular fibrillation was 4.76% (four of 84patients) vs 5.89% (five of 85patients) (p = 0.75), high grade atrioventricular block was 2.38% (two of 84patients) vs 4.71% (four of 85patients) (p = 0.41), and the in-hospital pneumonia rate was 2.38% (two of 84patients) vs 4.71% (four of 85patients) (p = 0.41), respectively. Patients with lower GFR were more likely to suffer from in-hospital acute heart failure (Killip class > 2) and atrial fibrillation in STEMI despite primary percutaneous coronary intervention. Renal function did not affect in-hospital pneumonia, pulseless ventricular tachycardia or ventricular fibrillation rates. The evaluation of kidney function through GFR in STEMI patients may make in-hospital complications more predictable.

The Performance of Equations That Estimate Glomerular Filtration Rate against Measured Urinary Creatinine Clearance in Critically Ill Patients.

The performance of glomerular filtration rate- (GFR-) estimating equations was studied against creatinine clearance measured by 24-hour urine collection (CrCl24h-urine) in critically ill patients. Methods. In this substudy of the PermiT trial (https://clinicaltrials.gov/ct2/show/ISRCTN68144998), patients from King Abdulaziz Medical City-Riyadh who had CrCl24h-urine were included. We estimated GFR using Cockroft–Gault (CG), modification of diet in renal disease study (MDRD), chronic kidney disease epidemiology collaboration (CKD-EPI), and Jelliffe equations. For the CG equation, we entered the actual weight in one calculation (CGactual-wt), and if BMI ≥30 kg/m2, we entered the ideal body weight (CGideal-wt) and the adjusted body weight (CGadjusted-wt) in two calculations. We calculated the MDRD equation based on 4 (MDRD-4) and 6 variables (MDRD-6). The performance of these equations was assessed by different ways including Spearman correlation, bias (difference between estimated GFR and CrCl24h-urine), precision (standard deviation of bias), and Bland–Altman plot analysis. Results. The cohort consisted of 237 patients (age 45 ± 20 years, males 75%, mechanically ventilated 99% with serum creatinine 101 ± 94 µmol/L and CrCl24h-urine 108 ± 69 ml/min/1.73 m2). The correlations between the different equations and CrCl24h-urine were modest (r: 0.62 to 0.79; p < 0.0001). Bias was statistically significant for CGactual-wt (21 ml/min), CGadjusted-wt (12 ml/min), and MDRD-6 (-10 ml/min) equations. Precision ranged from 46 to 54 ml/min. The sensitivity of equations to correctly classify CrCl24h-urine 30–59.9 ml/min/1.73 m2 was 17.2% for CGactual-wt, 30.0% for CGideal-wt, 31.0% for CGadjusted-wt, 31.0% for MDRD-4, 39.1% for MDRD-6, 13.8% for CKD-EPI, and 34.5% for Jelliffe equation. Conclusions. Commonly used GFR-estimating equations had limited ability to properly estimate CrCl24h-urine and to correctly classify GFR into clinically relevant ranges that usually determine dosing of medications.

The effects of aging on the renal function of a healthy population in Beijing and an evaluation of a range of estimation equations for glomerular filtration rate.

We investigated how age affected renal function in healthy subjects in Beijing and compared different estimated glomerular filtration rate (eGFR) equations. Kidney function was evaluated by five equations: Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI); Modification of Diet in Renal Disease Study (MDRD); the Chinese version of the MDRD (MDRDc); Full Age Spectrum (FAS); and Berlin Initiative Study (BIS). A total of 46,708 subjects were enrolled and followed-up for 3 years. All showed an increase in sCr and a reduction in eGFR with increasing age. Over the 3 years, the eGFR and serum creatinine (sCr) remained unchanged in most subjects. Different equations showed good consistency; the intraclass correlation coefficients (ICC) was 0.849 for males, and 0.817 for females. The CKD-EPI equation yielded higher GFR values than the other equations (according to sCr levels). For subjects aged over 70 years, the BIS equation produced the lowest eGFR values. In summary, we observed that the renal function of individuals was relatively stable with increasing age, although different eGFR equations yielded data that varied across different populations of subjects and sCr levels.

A Novel Creatinine-Based Equation to Estimate Glomerular Filtration Rate in Chinese Population With Chronic Kidney Disease: Implications for DOACs Dosing in Atrial Fibrillation Patients

Background: Over/under-estimating renal function may increase inappropriate dosing strategy associated adverse outcomes; however, previously reported equations to estimate renal function have limited accuracy in chronic kidney disease (CKD) patients. Consequently, we intended to develop a novel equation to precisely estimate renal function and subsequently guide clinical treatment for CKD patients. Methods: A novel approach, Xiangya-s equation, to estimate renal function for CKD patients was derived by linear regression analysis and validated in 1885 patients with measured glomerular filtration rate (mGFR) < 60 ml/min/1.73 m2 by renal dynamic imaging at three representative hospitals in China, with the performance evaluated by accuracy, bias and precision. In the meanwhile, 2,165 atrial fibrillation (AF) patients who initiated direct oral anticoagulants (DOACs) between December 2015 and December 2018 were identified and renal function was assessed by estimated creatinine clearance (eCrCl). Events per 100 patient-years was calculated. Cox proportional hazards regression was applied to compare the incidence of outcomes of each group. Results: Xiangya-s equation demonstrated higher accuracy, lower bias and improved precision when compared with 12 creatinine-based and 2 CysC-based reported equations to estimate GFR in multi-ethnic Chinese CKD patients. When we applied Xiangya-s equation to patients with AF and CKD prescribed DOACs, wide variability was discovered in eCrCl calculated by the Cockcroft-Gault (CG), Modification of Diet in Renal Disease Study (MDRD), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), Xiangya equation which we had developed for generally patients and Xiangya-s equations, which persisted after grouping by different renal function stages. Equation choice affected drug-dosing adjustments, with the formulas agreeing for only 1.19%, 5.52%, 33.22%, 26.32%, and 36.61% of potentially impacted patients for eCrCl cutoffs of <15, <30, 15–49, 30–49, ≥50 ml/min, respectively. Relative to CG equation, accordance in DOACs dosage was 81.08%, 88.54%, 62.25%, and 47.68% for MDRD, CKD-EPI, Xiangya and Xiangya-s equations for patients with CrCl < 50 ml/min (eCrCl cutoffs of <30, 30–49, ≥50 ml/min), respectively. Reclassification of renal function stages by Xiangya-s equation was significantly associated with stroke or systemic embolism, non-major clinically relevant bleeding and any bleeding events. Conclusion: Xiangya-s equation provides more accurate GFR estimates in Chinese CKD patients who need consecutive monitoring of renal function, which may assist clinicians in choosing appropriate drug dosages.

Renal excretion function in primary hyperparathyroidism: cardio-renal syndrome

Background. Primary hyperparathyroidism (PHPT) is an endocrine disease, due to the formation of excess parathyroid hormone secretion and a disturbance of phosphorus-calcium metabolism. PHPT is associated with reduced renal function and related increased mortality, therefore renal function impairment defined as a glomerular filtration rate (GFR) less than 60 mL/ min/1.73 m 2 is considered as an indication for surgical treatment. Some patients with PHPT have secondary cardio-renal syndrome (type 5), which is characterized by the presence of combined renal and cardiac pathology. THE AIM: Evaluate the GFR in patients with mild and symptomatic PHPT and its changes after parathyroidectomy and on medical treatment. Patients and methods : A cross-sectional comparative and prospective study was conducted on 100 patients with confirmed PHPT. A clinical and laboratory examination was performed at 6, 12, and/or 24 months and included an assessment of the PHPT complications as well as expression of cardio-renal syndrome according to the selected management tactics. Changes in GFR were evaluated in 29 patients after surgical treatment and in 27 patients on conservative management. Glomerular filtration rate was calculated by the Modification of Diet in Renal Disease Study (MDRD) formula. The chronic kidney disease (CKD) stage was estimated accordingly to current recommendations. Results: We included 100 patients (10 men and 90 women) with PHPT: 33 with mild and 67 with symptomatic PHPT. The median age was 57 years [51;61]. Mean GFR was 84,1 [73,3; 97,9] ml/ min/1,73 m 2 . Prevalence of CKD 3-4 in patients with PHPT was recorded at 11 %. Patient management tactics were determined in accordance with international recommendations. In the long-term period after surgery, we observed the decrease of GFR in patients with mild form within the limits of CKD 1-2 (p=0,013, W-test). No significant changes in GFR were noted during medical management and monitoring. Summary, the cardio-renal syndrome (CKD of any stage and cardiovascular pathology) was revealed in 26 % of patients. Arterial hypertension was registered in 40 %. Conclusions : We found a high frequency of renal function impairment in patients with PHPT, including patients with a mild form of the disease. We did not observe any significant improvement in renal filtration function, after surgical treatment and remission of PHPT. The safety of conservative tactics has been confirmed. The high frequency of cardiovascular pathology in patients with PHPT is beyond doubt and requires prospective studies in the larger cohorts of patients.

Comparison of the Modification of Diet in Renal Disease Study and Chronic Kidney Disease Epidemiology Collaboration Equations for Detection of Cardiovascular Risk: Tehran Lipid and Glucose Study.

ObjectivesThe study aimed to compare the Modification of Diet in Renal Disease Study (MDRD) and the Epidemiology Collaboration (CKD-EPI) equations for the detection of cardiovascular risk.MethodsData of 9,970 Tehranian participants aged ≥ 20 years were analyzed. The prevalence of cardiovascular disease (CVD), its risk factors, and 10-year atherosclerotic cardiovascular disease (ASCVD) risk were compared across the categories of glomerular filtration rate based on the MDRD and CKD-EPI equations. Chronic kidney disease (CKD) was defined as the estimated Glomerular Filtration Rate (eGFR) < 60 mL/min/1.73 m2 according to each equation.ResultsThe prevalence of CKD weighted to the 2016 Tehranian urban population was 11.0% (95% confidence interval: 10.3 - 11.6) and 9.7% (9.1 - 10.2) according to the MDRD and CKD-EPI equations, respectively. Besides, 8.3% and 1.5% of the participants with CKDMDRD and non-CKDMDRD were reclassified to non-CKDCKD-EPI and CKDCKD-EPI categories, respectively. Participants with CKDCKD-EPI but without CKDMDRD were more likely to be male and older, and more frequently had diabetes, hypertension, dyslipidemia, and CVD, when compared to those without CKD according to both equations; they were also more likely to be male, older, and smokers, and had less dyslipidemia and more CVD, when compared to those with CKD by using both equations. In multivariate logistic regression analysis, compared to CKDMDRD, the odds of CKDCKD-EPI were significantly higher for older age and lower for the female gender.ConclusionsCompared to MDRD, the CKD-EPI equation provides more appropriate detection of cardiovascular risk, which is caused by the reclassification of older individuals and fewer females into lower eGFR categories.

Correlation between renal parenchymal thickness and EGFR in chronic kidney disease

Objective: A prospective study developed to determine the relationship between renal parenchymal thickness and glomerular filtration rate in patients with chronic kidney disease.Materials and Methods: From June 2019 to June 2020, 50 patients were clinically diagnosed with chronic kidney disease. The lowest serum creatinine was used for calculation of the glomerular filtration rate (eGFR) using the Modification of Diet in Renal Disease Study (MDRD) equations. The ultrasounds were done by a single radiologist and reviewed by 2 consultants. The renal parenchymal thickness was measured in the longitudinal from the renal sinus to the outer renal cortical margin at upper, mid and lower levels of each kidney and the mean value was estimated for each kidney. Statistical Package for Social Science (SPSS 20.0) version used for data analysis and an unpaired test was applied to find the statistical significance. Pearson correlation test applied to find the correlation between the variables. A P value less than 0.05 (p

Comparative Performance of Creatinine-Based GFR Estimation Equations in Exceptional Longevity: The Rugao Longevity and Ageing Study.

PurposeReduced kidney function has been associated with an increased risk for adverse outcomes. Accurate assessment of glomerular filtration rate (GFR) is key to diagnosis and management of kidney disfunction. Debate exists on the best GFR estimation equation for elderly people. This study aimed to compare the predictive validity and discriminative ability of four GFR equations in relation to 2-year and 6-year mortality in exceptional longevity (EL) (those over 95 years old with intact health) individuals and is an ideal model to address factors relating to life span and age-related diseases.Patients and MethodsThis study used 6 years’ data of 278 EL from the Rugao longevity cohort. Baseline GFR was estimated using four equations: Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation, Modification of Diet in Renal Disease Study (MDRD) equation, Berlin Initiative Study-1 (BIS) equation, and modified MDRD equation. Predictive validity was tested using Cox proportional hazards analysis. Overall improvement in reclassification based on estimated GFR (eGFR) was assessed applying net reclassification improvement (NRI).ResultsMean age of participants was 97±2 years with median follow-up of 2.6 years. Median (IQR) eGFR by CKD-EPI, MDRD, BIS, and modified MDRD equations were 73.9 (62.2–77.6), 82.3 (67.4–98.6), 56.4 (47.9–63.9), and 101.5 (83.1–121.6) mL/min per 1.73 m2, respectively. Higher eGFREPI was associated with lower mortality after multivariate adjustment (for continuous eGFREPI, HRtwo-year 1.018, 95% CI 1.002–1.033, P=0.023; HRsix-year 1.013, 95% CI 1.002–1.025, P=0.022), while eGFR from other equations did not show any associations with mortality. NRI for two-year mortality was 0.14 and approximately significant, which may favor the CKD-EPI when compared to BIS equation (P=0.052).ConclusionThe CKD-EPI equation showed more accurate estimation of kidney function in the elderly with respect to GFR distribution and predictability of mortality risk.

Tubular secretion of creatinine and kidney function: an observational study

BackgroundPrior papers have been inconsistent regarding how much creatinine clearance (CrCl) overestimates glomerular filtration rate (GFR). A recent cross-sectional study suggested that measurement error alone could entirely account for the longstanding observation that CrCl/GFR ratio is larger when GFR is lower among patients with chronic kidney disease (CKD); but there have been no validation of this in other cohorts.MethodsTo fill these gaps in knowledge regarding the relation between CrCl and GFR, we conducted cross-sectional and longitudinal analysis of the Modification of Diet in Renal Disease study (MDRD) and African American Study of Kidney Disease and Hypertension (AASK); and cross-sectional analysis of a clinical dataset from the Mayo Clinic of four different patient populations (CKD patients, kidney transplant recipients, post kidney donation subgroup and potential kidney donors). In the cross-sectional analyses (MDRD, AASK and Mayo Clinic cohort), we examined the relation between the CrCl/iothalamate GFR (iGFR) ratio at different categories of iGFR or different levels of CrCl. In the MDRD and AASK longitudinal analyses, we studied how the CrCl/iGFR ratio changed with those who had improvement in iGFR (CrCl) over time versus those who had worsening of iGFR (CrCl) over time.ResultsObserved CrCl/iGFR ratios were generally on the lower end of the range reported in the literature for CKD (median 1.24 in MDRD, 1.13 in AASK and 1.25 in Mayo Clinic cohort). Among CKD patients in whom CrCl and iGFR were measured using different timed urine collections, CrCl/iGFR ratio were higher with lower iGFR categories but lower with lower CrCl categories. However, among CKD patients in whom CrCl and iGFR were measured using the same timed urine collections (which reduces dis-concordant measurement error), CrCl/iGFR ratio were higher with both lower iGFR categories and lower CrCl categories.ConclusionsThese data refute the recent suggestion that measurement error alone could entirely account for the longstanding observation that CrCl/GFR ratio increases as GFR decreases in CKD patients. They also highlight the lack of certainty in our knowledge with regard to how much CrCl actually overestimates GFR.

Comparison of creatinine-based methods for estimating glomerular filtration rate in patients with heart failure.

AimsGlomerular filtration rate is an important factor in management of heart failure (HF). Our objective was to validate eight creatinine‐based equations for estimating glomerular filtration rate (eGFR) in an HF population against measured glomerular filtration rate.Methods and resultsOne hundred forty‐six HF patients (mean age 68 ± 13 years, mean left ventricular ejection fraction 45% ± 15) within a single‐centre hospital that underwent 51Cr‐EDTA clearance between 2010 and 2018 were included in this retrospective study. eGFR was estimated by means of Cockcroft–Gault ideal and actual weight, the Modification of Diet in Renal Disease Study (MDRD), simplified MDRD with isotope dilution mass spectroscopy traceable calibration, the Chronic Kidney Disease Epidemiology Collaboration, revised Lund–Malmö, full age spectrum, and the Berlin Initiative Study 1. Mean measured glomerular filtration rate was 42 mL/min/1.73 m2. Pearson's correlation coefficient (r) had the highest precision for MDRD (r = 0.9), followed by revised Lund–Malmö (r = 0.88). All equations except MDRD (mean difference −4.8%) resulted in an overestimation of the renal function. The accuracy was below 75% for all equations except MDRD.ConclusionsNone of the exclusively creatinine‐based methods was accurate in predicting eGFR in HF patients. Our findings suggest that more accurate methods are needed for determining eGFR in patients with HF.

Agreement and Precision Analyses of Various Estimated Glomerular Filtration Rate Formulae in Cancer Patients

The accuracy of the estimated glomerular filtration rate (eGFR) in cancer patients is very important for dose adjustments of anti-malignancy drugs to reduce toxicities and enhance therapeutic outcomes. Therefore, the performance of eGFR equations, including their bias, precision, and accuracy, was explored in patients with varying stages of chronic kidney disease (CKD) who needed anti-cancer drugs. The reference glomerular filtration rate (GFR) was assessed by the 99mTc-diethylene triamine penta-acetic acid (99mTc-DTPA) plasma clearance method in 320 patients and compared with the GFRs estimated by i) the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation, ii) the unadjusted for body surface area (BSA) CKD-EPI equation, iii) the re-expressed Modification of Diet in Renal Disease (MDRD) study equation with the Thai racial factor, iv) the Thai eGFR equation, developed in CKD patients, v) the 2012 CKD-EPI creatinine-cystatin C, vi) the Cockcroft-Gault formula, and vii) the Janowitz and Williams equations for cancer patients. The mean reference GFR was 60.5 ± 33.4 mL/min/1.73 m2. The bias (mean error) values for the estimated GFR from the CKD-EPI equation, BSA-unadjusted CKD-EPI equation, re-expressed MDRD study equation with the Thai racial factor, and Thai eGFR, 2012 CKD-EPI creatinine-cystatin-C, Cockcroft-Gault, and Janowitz and Williams equations were −2.68, 1.06, −7.70, −8.73, 13.37, 1.43, and 2.03 mL/min, respectively, the precision (standard deviation of bias) values were 6.89, 6.07, 14.02, 11.54, 20.85, 10.58, and 8.74 mL/min, respectively, and the accuracy (root-mean square error) values were 7.38, 6.15, 15.97, 14.16, 24.74, 10.66, and 8.96 mL/min, respectively. In conclusion, the estimated GFR from the BSA-unadjusted CKD-EPI equation demonstrated the least bias along with the highest precision and accuracy. Further studies on the outcomes of anti-cancer drug dose adjustments using this equation versus the current standard equation will be valuable.

Evolution of Equations for Estimating Renal Function and Their Application to the Dosing of New Antimicrobials.

Objective: To address the background and rationale for the recent introduction of the Modification of Diet in Renal Disease (MDRD) equation for renal dose adjustment of antimicrobials and to provide recommendations for pharmacists dosing new antimicrobial agents. Data Sources: Comprehensive MEDLINE and EMBASE literature searches (from August 2018 to October 2019) were performed. Search terms included creatinine clearance, Cockcroft-Gault, MDRD, and glomerular filtration rate and a subsequent search included the preceding terms AND antimicrobials OR antibiotics. Study Selection and Data Extraction: Available English-language studies on the derivation and/or use of the Cockcroft-Gault (CG) and MDRD study equation were evaluated as well as those that specifically discussed their use for dosing antimicrobial agents. Data Synthesis: The US Food and Drug Administration (FDA) approval of delafloxacin and meropenem-vaborbactam in 2017 ushered in a new era in renal dosing of antibiotics, in that both agents are recommended to be dosed by the MDRD equation. Studies demonstrate that the CG and MDRD equations can result in discrepant dosing recommendations. Relevance to Patient Care and Clinical Practice: The renal estimation equation recommended in a new antibiotic label should dictate the dosing of that medication. It is noteworthy that these equations are not interchangeable. Conclusion: Recently approved antimicrobials utilizing the MDRD equation for renal dose adjustment will be interspersed with old and new antimicrobials utilizing the CG equation because of lack of singular guidance by the FDA. This requires pharmacists to be vigilant in evaluating drug labels to determine which equation is recommended and to understand the differences, strengths, and limitations of each equation.