BIS1 Equations Research Articles

#2255 Impact and interest of using the EKFC formula instead of CKD-EPI in estimating GFR in the laboratory on clinical practice

Abstract Background and Aims Early diagnosing Chronic Kidney Disease (CKD) is of major importance in daily practice, and the automatic reporting of the estimated glomerular filtration rate (eGFR) for all plasma creatinine (Pcr) determinations is mandatory. The CKD-EPI 2009 formula [1] is considered the most accurate creatinine-based GFR estimating formula in adults in Europe and is currently utilized by laboratories. However, CKD-EPI equation is inadequate in young adults < 25 years and CKD-EPI equation is debated in the elderly over 75 years, with the BIS1 equation [2] showing better performance in this age group. The creatinine-based European Kidney Function Consortium (EKFC) equation [3] provides continuous GFR estimation from 2 years to adulthood and the elderly, presenting itself as a potential alternative to both the CKD-EPI and BIS1 equations. Our objective was to assess the impact of using the EKFC equation (and/or BIS1 in the elderly) compared to CKD-EPI in daily practice in identifying patients with a GFR < 60 or < 30 ml/min/1.73 m2, which represents the threshold for referring to a nephrologist and adjusting drug dosage, respectively. Method We retrieved data from the laboratory database, including gender, age, and the lowest measurement of Pcr for all patients over 18 years who underwent Pcr determination in November 2023. eGFR was calculated for all patients using the CKD-EPI and the EKFC equation. For patients over 70 years, eGFR was also estimated with the BIS1 equation. Pcr was assessed using an enzymatic method traceable to IDMS (Architect c®, Abbott Diagnostics). Results were expressed as the mean bias between EKFC and BIS1, and CKD-EPI (considered as the reference) according to age groups, and as the number of patients misclassified as < 60 or < 30 ml/min/1.73 m2. Results 10 066 patients (50.5% females, mean age 56.0 ± 21.2 years [18.0-106.7]) underwent Pcr determination (mean 84.7 ± 72.3 µmol/L) with 1 706 (16.9%) and 405 (4.0%) having a GFR < 60 or < 30 ml/min/1.73 m2, respectively. EKFC and BIS underestimated CKD-EPI eGFR in all groups, but especially in the groups of young adults and the elderly. However, the number of misclassified patients is small, except in the elderly when CKD-EPI is considered less accurate. Conclusion The use of EKFC in laboratories to estimate eGFR offers continuous GFR estimation from 2 years to adulthood and elderly and could be an alternative to both CKD-EPI and BIS1. The automatic reporting of eGFR with EKFC by laboratories in Europe could allow for an earlier diagnosis of CKD and initiation of nephroprotection in young adults, in addition to providing better nephrological care for the elderly.

Comparison of the applicability of seven calculation equations of glomerular filtration rate among elderly people in China

BackgroundAt present, estimated glomerular filtration rate (eGFR) remains the most frequently utilized parameter in the evaluation of kidney injury severity. Numerous equations have been formulated based on serum creatinine (Scr) or serum cystatin C (Cysc) levels. However, there is a lack of consensus regarding the efficacy of these equations in assessing eGFR, particularly for elderly individuals in China. This study aimed to evaluate the applicability of the MDRD, MDRDc, CKD-EPI series, BIS1, and FAS equations within the Chinese elderly population.MethodsA cohort of 298 elderly patients with measured GFR (mGFR) was enrolled. The patients were categorized into three subgroups based on their mGFR levels. The eGFR performance was examined, taking into account bias, interquartile range (IQR), accuracy P30, and root-mean-square error (RMSE). Bland–Altman plots were employed to verify the validity of eGFR.ResultsThe participants had a median age of 71 years, with 167 (56.0%) being male. Overall, no significant differences in bias were observed among the seven equations (P > 0.05). In terms of IQR, P30, and RMSE, the BIS1 equation demonstrated superior accuracy (14.61, 72.1%, and 13.53, respectively). When mGFR < 30 ml/min/1.73 m2, all equations underestimated the true GFR, with the highest accuracy reaching only 59%. Bland–Altman plots indicated that the BIS1 equation exhibited the highest accuracy, featuring a 95% confidence interval (CI) width of 52.37.ConclusionsThis study suggested that the BIS1 equation stands out as the most applicable for estimating GFR in Chinese elderly patients with normal renal function or only moderate decline. 2020NL-085-03, 2020.08.10, retrospectively registered.

#6279 ESKD TREATMENTS: A DIFFICULT CHOICE TO ELDERLY PATIENTS?

Abstract Background and Aims End stage kidney disease (ESKD) treatment choice may be very difficult mainly for elderly patients. Dialysis can be burdensome for the frail patients, offering more aggressive procedures and less quality of life. Conservative Care (CC) may shorten life in a fit patient. This study aimed to describe our elderly patients' choices when it comes to CKD treatment options and reflect about them. Method We designed a single center retrospective observational, cross-sectional study regarding patients (pts) over 80 years old (yo) who attend the appointment of ESKD treatment modalities between July 2015 and and December 2021, since a Conservative Care Program is available in our hospital. Results During these 6,5 years, 113 pts over 80 yo were attended. Mean age was 85 yo (range 80–103). 66% were male and mean charlson comorbidity index (CMI) was 7 (sd ± 1,2). Mean seric creatinine was 3,69 mg/dl (sd 0,99; range 1,8-7,0). Mean estimated glomerular filtration rate was 17,41 (sd ±4,12) and 14,64 (sd ± 7,6) ml/min per 1.73 m2 when calculated with BIS1 and CKD-EPI equation, respectively. Two patients were already on a regular program of dialysis. Regarding CKD etiology, 31,9% was from multifactorial origin, 27,4% was from undetermined origin, 10,6% was hypertensive, 8% was diabetic, 6,2% was from chronic pyelonephritis and 9,7% was in the context of cardiorenal syndrome. Regarding treatment options, 54% chose hemodialysis, 38,9% chose conservative care (CC), 2,7% chose peritoneal dialysis and 2,7% refused any treatment. We also observed a significant increase in the CC during these 6.5 years of study. Of those who chose hemodialysis, 22,95% (n = 14) died before starting on a regular program of dialysis, 62,3% (n = 38) actually started on a regular program and 14,75% (n = 9) still maintain follow-up in nephrology appointment. Regarding those who died before starting on dialysis treatment, the mean time between choosing dialysis and death was 1,36 years (range 115 days to 5,46 years, median 1,36 years), and between starting on a regular program and death was 1,38 year (range 11 days to 4,9 years). The main cause of death was unknown (66%) (by lack of data), followed by infectious cause (26,6%). Considering those who chose CC, 31,8% (n = 14) died before starting the regular follow up, 54,5% (n = 24) are on a regular program of follow up, and 4,5% (n = 2) lately decided for dialysis. Regarding those who died before CC, the mean time between choosing it and death was approximately 1 year (range 29 days to 3,4 years), and between starting on a regular follow up and death was 0,68 years (range 14 days to 1,7 years). We didn’t find any statistical significance between CMI and the ESRD modality chosen (p = 0.709) or the occurrence of death (p = 0,496). Conclusion Even considering the poor prognosis and the high mortality rate, the majority of patients over 80 years old still chose dialysis over conservative kidney treatment. In our cohort, there was no survival benefit from those who choose dialysis instead of CC. CC should be offered as an alternative treatment to all the patients who may not benefit from dialysis. It is important to find tools who help us to guide patients in the best suitable choice in regard to ESKD treatments.

A back propagation neural network approach to estimate the glomerular filtration rate in an older population

BackgroundThe use of creatinine-based glomerular filtration rate (GFR)-estimating equations to evaluate kidney function in elderly individuals does not appear to offer any performance advantages. We therefore aimed to develop an accurate GFR-estimating tool for this age group.MethodsAdults aged ≥ 65 years who underwent GFR measurement by technetium-99 m-diethylene triamine pentaacetic acid (99mTc-DTPA) renal dynamic imaging were included. Data were randomly split into a training set containing 80% of the participants and a test set containing the remaining 20% of the subjects. The Back propagation neural network (BPNN) approach was used to derive a novel GFR estimation tool; then we compared the performance of the BPNN tool with six creatinine-based equations (Chronic Kidney Disease-Epidemiology Collaboration [CKD-EPI], European Kidney Function Consortium [EKFC], Berlin Initiative Study-1 [BIS1], Lund-Malmö Revised [LMR], Asian modified CKD-EPI, and Modification of Diet in Renal Disease [MDRD]) in the test cohort. Three equation performance criteria were considered: bias (difference between measured GFR and estimated GFR), precision (interquartile range [IQR] of the median difference), and accuracy P30 (percentage of GFR estimates that are within 30% of measured GFR).ResultsThe study included 1,222 older adults. The mean age of both the training cohort (n = 978) and the test cohort (n = 244) was 72 ± 6 years, with 544 (55.6%) and 129 (52.9%) males, respectively. The median bias of BPNN was 2.06 ml/min/1.73 m2, which was smaller than that of LMR (4.59 ml/min/1.73 m2; p = 0.03), and higher than that of the Asian modified CKD-EPI (-1.43 ml/min/1.73 m2; p = 0.02). The median bias between BPNN and each of CKD-EPI (2.19 ml/min/1.73 m2; p = 0.31), EKFC (-1.41 ml/min/1.73 m2; p = 0.26), BIS1 (0.64 ml/min/1.73 m2; p = 0.99), and MDRD (1.11 ml/min/1.73 m2; p = 0.45) was not significant. However, the BPNN had the highest precision IQR (14.31 ml/min/1.73 m2) and the greatest accuracy P30 among all equations (78.28%). At measured GFR < 45 ml/min/1.73 m2, the BPNN has highest accuracy P30 (70.69%), and highest precision IQR (12.46 ml/min/1.73 m2). The biases of BPNN and BIS1 equations were similar (0.74 [-1.55−2.78] and 0.24 [-2.58−1.61], respectively), smaller than any other equation.ConclusionsThe novel BPNN tool is more accurate than the currently available creatinine-based GFR estimation equations in an older population and could be recommended for routine clinical use.

Optimal Glomerular Filtration Rate Equations for Various Age Groups, Disease Conditions and Ethnicities in Asia: A Systematic Review.

(1) Background: The performance of estimated glomerular filtration rate (eGFR) equations in the Asian population has been widely questioned. The primary objective of this study was to gather evidence regarding optimal GFR equations in Asia for various age groups, disease conditions, and ethnicities. The secondary objective was to see whether the equations based on the combination of creatinine and cystatin C biomarkers if employed are satisfactory across different age groups and disease conditions in various ethnicities in Asia compared to those based on either of the single biomarkers. (2) Methods: Validation studies that had both creatinine and cystatin C-based equations either alone or in combination, validated in specific disease conditions, and those which compared the performance of these equations with exogenous markers were eligible only. The bias, precision, and 30% accuracy (P30) of each equation were recorded accordingly. (3) Results: Twenty-one studies consisting of 11,371 participants were included and 54 equations were extracted. The bias, precision, and P30 accuracies of the equations ranged from -14.54 to 9.96 mL/min/1.73 m2, 1.61 to 59.85 mL/min/1.73 m2, and 4.7% to 96.10%. The highest values of P30 accuracies were found for the JSN-CKDI equation (96.10%) in Chinese adult renal transplant recipients, for the BIS-2 equation (94.5%) in Chinese elderly CKD patients, and Filler equation (93.70%) also in Chinese adult renal transplant recipients. (4) Conclusions: Optimal equations were identified accordingly and it was proven that combination biomarker equations are more precise and accurate in most of the age groups and disease conditions. These can be considered equations of choice for the specific age groups, disease conditions, and ethnicities within Asia.

Comparison of estimated glomerular filtration rate equations based on serum creatinine-, cystatin C- and creatinine-cystatin C in elderly Chinese patients.

This study aimed to further evaluate the accuracy of eleven GFR equations in different subgroups of an elderly Chinese hospitalized population. All participants of the study were divided into seven separate groups including age-subgroup, sex-subgroup, GFR Staging-subgroup and whether combined with diabetic, hypertensive, coronary heart disease (CHD) and cerebrovascular disease. Referring to Tc-99m-DTPA dual plasma sample clearance method, six serum creatinine (Cr)-based [Cockcroft-Gault (CG), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPICr), Lund-Malmö Revised (LMR), Berlin Initiative Study (BIS1), Full Age Spectrum (FASCr) and European Kidney Function Consortium (EKFC)], two serum cystatin C(Cys)-based (CKD-EPICys and FASCys), and three Cr-Cys combination based (CKD-EPICr-Cys, BIS2 and FASCr-Cys) equations were employed. Bias, interquartile range of the median difference (IQR), P30, and GFR misclassification rate were calculated to compare the performance of the selected equations. A total of 359 elderly Chinese patients were enrolled. Overall, median mGFR was 36.91(25.26,56.32)ml/min/1.73m2. Smaller biases (ml/min/1.73m2) were shown in CKD-EPICr and BIS1 equations (0.75 and 0.61). IQR (ml/min/1.73m2) was least with BIS2 equation and FASCr-Cys equation (10.34 and 10.65). For accuracy (P30), performance of FASCr-Cys, BIS2, and BIS1 equation was superior (78.3%, 78.0%, and 74.7%, respectively). In terms of RMSE (ml/min/1.73m2), BIS1 and FASCr-Cys equation performed better (12.44 and 12.51). Overall, this study showed that the eGFR equations were less accurate in the diabetic and non-hypertension group than in the non-diabetic and hypertension group, respectively. Among all enrolled equations, the BIS2 and FASCr-Cys equations might be the best choice to evaluate glomerular filtration rate in Chinese elderly patients.

Age and the Course of GFR in Persons Aged 70 and Above.

In older adults, data on the age-related course of GFR are scarce, which might lead to misjudgment of the clinical relevance of reduced GFR in old age. To describe the course of eGFR in older adults and derive reference values in population-based individuals, we used the longitudinal design of the Berlin Initiative Study (BIS) with a repeated estimation of GFR over a median of 6.1 years of follow-up. In 2069 community-dwelling older individuals (mean inclusion age 80 years, range 70-99), GFR was estimated biennially with the BIS-2 equation, including standardized creatinine and cystatin C levels, sex, and age. We described the crude and adjusted course using a mixed-effects model and analyzed the influence of death on the GFR course applying joint models. GFR slopes were compared using GFR equations on the basis of creatinine and/or cystatin C. We observed a decreasing, thus nonlinear, eGFR decline with increasing age in a population of old adults. The estimated 1-year slope for ages 75 and 90 diminished for men from -1.67 to -0.99 and for women from -1.52 to -0.97. The modeled mean eGFR for men aged ≥79 and women ≥78 was below 60 ml/min per 1.73 m2. Multivariable adjustment attenuated slopes only minimally. Taking death into account by applying joint models did not alter the nonlinear eGFR decline. Using eGFR equations on the basis of creatinine only showed linear slope patterns in contrast to nonlinear patterns for equations including cystatin C. The eGFR decline depended on sex and age and changed only marginally after multivariable adjustment but decelerated with increasing age. Equations including cystatin C demonstrated a nonlinear slope challenging the previously assumed linearity of the decline of eGFR in old age.

MO510: CKD Progression in a Cohort of Older Community-Dwelling Adults– Results From the Berlin Initiative Study (BIS)

Abstract BACKGROUND AND AIMS Data on the estimated glomerular filtration rate (eGFR) over time in older populations are scarce. Identifying patterns of eGFR progression is essential for a better understanding of chronic kidney disease (CKD) in older adults. METHOD We used data from the BIS, a community-dwelling cohort of 2069 people aged 70 or older. Participants were recruited between 2009 and 2011. After baseline assessment, four follow-up visits were conducted biennially over a total observation period of 8 years. During all study visits, eGFR and CKD stages based on KIDGO guidelines were assessed using the creatinine and cystatin C-based BIS2 equation (eGFRBIS2). Additionally, we used the creatinine-based EKFC equation (eGFREKFC). In a sub-analysis, we included only non-deceased participants with complete attendance at all study visits and valid eGFR values at all measurements. RESULTS At baseline, the mean age was 80.4 years (SD = 6.7), and 52.6 % were females. Prevalence was highest for CKD stage 2 (45.4%) and 3 (49.3%). After 8 years, the prevalence for CKD stages 1 and 2 decreased, whereas stages 3 and 4 showed a consistent upward trend resulting in 18.4%, 72.4% and 8.9% of participants in stages 2, 3 and 4, respectively. Mean eGFRBIS2 decreased from 58.1 (SD = 15.2) to 48.3 (SD = 13.3) mL/min/1.73 m² after 8 years. Mean eGFREKFC showed a similar trend with estimates being slightly higher (60.4 versus 54.2 mL/min/1.73 m2 after 8 years). Same trends applied to the subgroup with complete attendance (mean age: 77.4 years). However, compared with the total population they showed a higher mean eGFRBIS2 (63.3 versus 58.1 mL/min/1.73 m²) and lower prevalence of CKD stages 3 and 4 (stage 2: 59.4 versus 45.4%; stage 3: 37.1 versus 49.3% stage 4: 1.2 versus 3.6%) at baseline. CONCLUSION We found that over the observation period of 8 years, mean eGFRBIS2 decreased by 9.8 mL/min/1.73 m2 resulting in an increasing prevalence of CKD stages 3 and 4 by 23.1 and 5.3%, respectively. This was observed in the total population as well as in the subgroup with complete study attendance.

Clinical and Prognostic Implications of Estimating Glomerular Filtration Rate by Three Different Creatinine-Based Equations in Older Nursing Home Residents.

BackgroundAccording to the international literature, the percentage of nursing home (NH) residents with renal insufficiency is very high, ranging between 22 and 78%. Diminished kidney function represents a risk factor for drug overdosage, adverse drug reactions, end-stage renal disease, disability, morbidity, and mortality. Several studies suggested that screening for chronic kidney disease (CKD) in high-risk and older populations may represent a cost-effective approach to reducing progression to renal failure and CKD mortality.ObjectiveThis study aimed (i) to investigate to what extent CKD may be staged interchangeably by three different creatinine-based estimated glomerular filtration rate (eGFR) equations in a sample of older adults living in long-term care facilities; (ii) to investigate factors explaining differences among eGFR equations; and (iii) to compare the predictivity of different creatinine-based eGFR equations with respect to all-cause mortality.MethodsA total of 522 residents aged 65 years and older participated in a prospective cohort study of 9 long-term care facilities in Calabria. eGFR was calculated by Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), Berlin initiative study (BIS), and full age spectrum (FAS) equations. Disability in at least one activity of daily living (ADL), depression, cognitive impairment, comorbidity, and malnutrition was considered in the analysis. Statistical analysis was carried out by Bland–Altman analysis, and 2-year mortality was investigated by Kaplan–Meier curves and Cox regression analysis.ResultsDepending on the adopted equation, the prevalence of NH residents with impaired renal function (eGFR < 60 ml/min/1.73 m2) ranged between 58.2% for the CKD-EPI and 79.1% for the BIS1 equation. The average difference between BIS and FAS was nearly negligible (0.45 ml/min/1.73 m2), while a significant bias was detected between CKD-EPI and BIS and also between CKD-EPI and FAS (6.21 ml/min/1.73 m2 and 6.65 ml/min/1.73 m2, respectively). Although the eGFR study equations had comparable prognostic accuracy in terms of mortality risk, BIS and FAS were able to reclassify NH residents pertaining to a low-risk group with CKD-EPI, and this reclassification improves the discriminative capacity of CKD-EPI with respect to overall mortality.ConclusionDespite the relatively good correlation between eGFRs calculated using all adopted equations, the findings in this study reported clearly demonstrated that CKD-EPI and BIS/FAS equations are not interchangeable to assess eGFR among older people and particularly in institutionalized and frail older subjects.

Kidney Function According to Different Equations in Patients Admitted to a Cardiology Unit and Impact on Outcome.

Background: This paper aims to evaluate the concordance between the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula and alternative equations and to assess their predictive power for all-cause mortality in unselected patients discharged alive from a cardiology ward. Methods: We retrospectively included patients admitted to our Cardiology Division independently of their diagnosis. The total population was classified according to Kidney Disease: Improving Global Outcomes (KDIGO) categories, as follows: G1 (estimated glomerular filtration rate (eGFR) ≥90 mL/min/1.73 m2); G2 (eGFR 89–60 mL/min/1.73 m2); G3a (eGFR 59–45 mL/min/1.73 m2); G3b (eGFR 44–30 mL/min/1.73 m2); G4 (eGFR 29–15 mL/min/1.73 m2); G5 (eGFR <15 mL/min/1.73 m2). Cockcroft-Gault (CG), CG adjusted for body surface area (CG-BSA), Modification of Diet in Renal Disease (MDRD), Berlin Initiative Study (BIS-1), and Full Age Spectrum (FAS) equations were also assessed. Results: A total of 806 patients were included. Good agreement was found between the CKD-EPI formula and CG-BSA, MDRD, BIS-1, and FAS equations. In subjects younger than 65 years or aged ≥85 years, CKD-EPI and MDRD showed the highest agreement (Cohen’s kappa (K) 0.881 and 0.588, respectively) while CG showed the lowest. After a median follow-up of 407 days, overall mortality was 8.2%. The risk of death was higher in lower eGFR classes (G3b HR4.35; 95%CI 1.05–17.80; G4 HR7.13; 95%CI 1.63–31.23; G5 HR25.91; 95%CI 6.63–101.21). The discriminant capability of death prediction tested with ROC curves showed the best results for BIS-1 and FAS equations. Conclusion: In our cohort, the concordance between CKD-EPI and other equations decreased with age, with the MDRD formula showing the best agreement in both younger and older patients. Overall, mortality rates increased with the renal function decreasing. In patients aged ≥75 years, the best discriminant capability for death prediction was found for BIS-1 and FAS equations.

DIFFERENCES IN PREVALENCE OF CHRONIC KIDNEY DISEASE USING BERLIN INITIATIVE STUDY 1 AND CKD-EPI EQUATIONS IN ELDERY SUBJECTS (ENAH STUDY)

Objective: Glomerular filtration rate (GFR) is considered to be the best indicator of renal function in health and disease, and according to the guidelines should be estimated using CKD-Epi equation. CKD-Epi has a limitation when estimating GFR for elderly subjects. Recently, Berlin Initiative Study 1 equation (BIS1) was suggested to be more appropriate for subjects aged 70 or older. Our aim was to analyze differences in estimation GFR and prevalence of CKD when using CKD-Epi and BIS1. Design and method: Data on 2194 adult subjects (random sample of rural population; 383 &gt; = 70 yr, 39.2% male) were analyzed. CKD-Epi and BIS1 were used to estimate eGFR in total group, elderly (&gt; = 70 yr) and younger than 70 yr. Differences between equations were analyzed using chi-square test, kappa inter-rater agreement and Bland-Altman plot analysis. Results: Significant difference in proportion of patients in CKD stages when comparing CKD-Epi vs BIS1 for subjects older than 70 years, p &lt; 0.001 was observed. When estimating GFR with two equations we observed a higher difference in prevalence in elderly subjects for eGFR values &lt; 60 ml/min and &gt; = 60 ml/min than in subjects &lt;70 years (Figure 1). The difference in prevalence between CKD-Epi and BIS1 for older subjects was 22.7%, while for younger 0.008%, p &lt; 0.001 (Figure 1). The agreement between CKD-Epi and BIS1 in older patients was lower than in younger subjects (kappa 0.56 vs kappa 0.67). When analyzing the total population there were more patients in stage 3a CKD using BIS1 equation than using CKD-Epi equation (10.2% vs. 5.8%). A systematic difference was found between the formulas, with BIS1 mean value 8.0 ml/min being lower than that of CKD-Epi (95% limits of agreement: +1.9 to -17.8). Conclusions: Significant difference between CKD-Epi and BIS1 was found. There was a higher difference in CKD prevalence in older subjects and also agreement between two formulas was lower in that subgroup. Our results suggest that specific equation suitable for elderly subjects should be used.

Comparison of different methods to estimate glomerular filtration rate in older adults

Glomerular filtration rate (GFR) estimation in older adults using a creatinine clearance/24-hour (CrCl) or an equation based on serum creatinine, are often considered equivalent by clinicians. To compare GFR estimated (eGFR) with the available equations and measured CrCl in patients ≥ 70 years. A secondary aim was to know the differences in chronic kidney disease (CKD) classification, when using the different eGFR formulas. In 144 patients aged 77 ± 5 years (58% men), CrCl was measured and GFR was estimated using MDRD, CKD-EPI, BIS-1 and FAS formulas. The eGFR and the stage of CKD were compared according to the different equations used. GFR estimated by MDRD and CKD-EPI equations was 7.8 and 8.4 mL/min/1.73 m2 lower than 24-hour ClCr, respectively. This difference was even greater using the BIS-1 and FAS equations. Twenty-four-hour CrCl classified 47.2% of the patients in a category of renal function > 60 mL/min/1.73 m2, while MDRD and CKD-EPI equations classified just over a third, and BIS-1 and FAS formulas around 20% of the patients. The practice of considering equivalent the GFR estimation using the creatinine-based equations with measured creatinine clearance in older adults should be reconsidered, because their results differ markedly.

Renal function and delirium in older fracture patients: different information from different formulas?

Objectivesthe association between renal function and delirium has not been investigated in older fracture patients. Creatinine is frequently low in these subjects, which may influence the association between delirium and renal function as estimated with creatinine-based formulas. Cystatin C could be a more reliable filtration marker in these patients. Aimto confirm the association between renal function and delirium in older fracture patients comparing creatinine- and cystatin-based estimated glomerular filtration rate (eGFR) Methodspatients aged 65+ requiring surgery for traumatic bone fractures were included. Six equations were used to calculate eGFR, based on serum creatinine and/or cystatin C obtained within 24 h of admission: Modification of Diet in Renal Disease (MDRD), Chronic Kidney Disease Epidemiology (CKD-EPIcr, CKD-EPIcys, CKD-EPIcr-cys) and Berlin Initiative Study equations (BIS-1, BIS-2). Delirium was identified with a chart-based method. Results571 patients (mean age 83) were enrolled. Delirium occurred in the 34% and was associated with a lower eGFR regardless of the equation used. In a multivariable model, the association between moderate renal impairment (eGFR 30–60 ml/min/1.73 m2) and delirium remained significant in patients aged 75–84 and only when estimated with cystatin-based or BIS-1 equations. Only dementia was significantly associated with delirium in subjects 85+. Conclusionsin older fracture patients, moderate renal impairment was independently associated with delirium only among subjects aged 75–84, when eGFR was estimated with cystatin-based or BIS 1 equations, and not with the most commonly used equations (MDRD, CKD-EPIcr).

P3759Comparison of equations for renal function assessment and major adverse outcomes in atrial fibrillation: an analysis from the EORP-AF long-term general registry

Abstract Background Several equations exist to estimate creatinine clearance according to serum creatinine values and baseline characteristics. The CKD-EPI equation is usually recommended in general population, while the Cockroft-Gault (CG) equation has been used in atrial fibrillation (AF) clinical trials. Purpose To perform a comparison between 6 different equations for evaluation of renal function in AF patients. Methods We calculated CKD-EPI, CG, body surface area adjusted CG (CG BSA), MDRD, BIS1 and FAS equations in AF patients enrolled in the EORP-AF Long-Term General Registry. Outcomes at 1-year follow-up were considered. Results Renal equations were calculated in 7725 patients. According to CKD-EPI mean (SD) creatinine clearance was 69.14 (21.06) mL/min/1.73 m2. Taking CKD-EPI as reference, the MDRD equation showed the highest agreement (weighted kappa [95% CI]: 0.843 [0.833–0.852]), while CK showed the lowest agreement (weighted kappa [95% CI]: 0.593 [0.580–0.606]. The remaining equations showed moderate agreement. Cox regression analysis showed that all equations were inversely associated with all major adverse outcomes [Figure]. The CKD-EPI equation showed modest predictive ability for the three outcomes (c-statistics: any TE/ACS/CV Death: 0.63379; CV Death: 0.68512; All-Cause Death: 0.67183), with all other equations reporting higher c-statistics (delta-c statistic ranging from +0.01497 for FAS equation for any TE/ACS/CV Death to +0.04547 for CG BSA for all-cause death) for all outcomes (all p&lt;0.0001, for any equation for any outcome). Compared to CKD-EPI, all the other equations showed an improvement in prediction of outcomes, according to IDI and NRI, with the exception of FAS equation for any TE/ACS/CV Death. CG BSA equation showed the greatest improvement in prediction of outcomes compared to CKD-EPI (relative IDI: 21.9% for any TE/ACS/CV Death, 28.8% for CV Death, 34.4% for All-Cause Death). Cox Regression Analysis Conclusions Compared to CKD-EPI equation, all the other equations for creatine clearance has stronger associations with adverse outcomes, with the CG BSA reporting the higher yield for all the outcomes considered.

Concordancia entre las ecuaciones «Chronic Kidney Disease Epidemiological Collaboration» y «Modification of Diet in Renal Disease» con la «Berlin Initiative Study» para estimar la función renal en las personas mayores

ObjectiveEstimated glomerular filtration rate (eGFR) is calculated routinely using creatinine-based formulas, but their reliability in the elderly is limited. The aim of this study was to analyse the concordance between the BIS1 equation which is specific for the elderly, and the usual CKD-EPI and MDRD-IDMS in a large population over 70 years of age. Material and methodsRetrospective cross-sectional study in which the eGFR was calculated using BIS1, CKD-EPI and MDRD-IDMS equations based on gender, age, and creatinine data of 85,089 subjects (58.5% women, mean age 78 years [IQR 73-83]).The following statistics were carried out: Wilcoxon test, Bland-Altman graphic analysis, study of the concordance using the intraclass correlation coefficient (ICC), and comparison tables for the classification of CKD. ResultsThe median of the eGFRs using BIS1 was 58mL/min/1.73m2 (IQR 48-70), using CKD-EPI was 68mL/min/1.73m2 (IQR 53-84), and using MDRD it was 68mL/min/1.73m2 (IQR 53-82). The concordance between BIS1 and CKD-EPI (intraclass correlation coefficient =0.87) was found to be acceptable. It was lower with MDRD (intraclass correlation coefficient =0.81). A mean difference of 8mL/min/1.73m2 (SD 2.6-18) was found BIS1 vs. CKD-EPI, and 10mL/min/1.73m2 (SD 6-27) with BIS1 vs. MDRD, which was maintained when stratifying by gender and age groups. ConclusionsDespite the acceptable statistical agreement, the eGFR obtained with the BIS1 equation is not interchangeable with CKD-EPI or with MDRD-IDMS. The BIS1 equation gives lower values than CKD-EPI, and classifies patients into a higher level of CKD, mainly when the eGFR is above 30mL/min/1.73 m2.

Prevalence of chronic kidney disease in the elderly using the ASPirin in Reducing Events in the Elderly study cohort.

The prevalence of chronic kidney disease (CKD) in the elderly is controversial because age-related decline in kidney function may not truly reflect underlying kidney disease. We estimate the baseline prevalence and predictors of CKD using the CKD Epidemiology Collaboration (CKD-EPIeGFR ) and Berlin Initiative Study 1 (BIS1eGFR ) eGFR equations in the ASPirin in Reducing Events in the Elderly (ASPREE) trial cohort of healthy older participants. GFR was estimated using CKD-EPI and BIS1 equations. CKD was defined as eGFR <60 mL/min/1.73 m2 or ≥ 60 mL/min/1.73 m2 with urine albumin creatinine ratio (UACR) ≥ 3 mg/mmol. Logistic regression was used to identify predictors of CKD prevalence defined by each eGFR equation. Data for analysis were complete for 17,762 participants. Mean age was 75.1 years (SD 5); 56.4% were female, 76.4% had hypertension, 9% had diabetes mellitus. Mean CKD-EPIeGFR was 73.0 (SD 14.2), compared with mean BIS1eGFR of 62.7 (11.4). Median UACR was 0.8 (IQR 0.5, 1.5) mg/mmol. Prevalence of CKD by CKD-EPIeGFR was 27% (predominantly due to normoalbuminuric stage 3a CKD), substantially lower than 47.1% by BIS1eGFR ; the difference was predominantly driven by reclassification of individuals from G1 and G2 CKD to stage G3a without albuminuria. Increased prevalence of CKD by either equation was related to older age, hypertension, diabetes, or higher body mass index. Prevalence of CKD with CKD-EPIeGFR was 27%, and doubled using the elderly specific BIS1eGFR , with most participants reclassified from stage 2 to stage 3a. Increased prevalence of CKD was related older age, hypertension, diabetes, or increased body mass index.

Using a three-compartment model improves the estimation of iohexol clearance to assess glomerular filtration rate

Plasma clearance of iohexol is a key tool to precisely determine glomerular filtration rate (GFR) in clinical research and clinical practice. Despite evidence that iohexol pharmacokinetics are described best by three-compartment models, two-compartment approaches (Schwartz approach) are customary, which might result in avoidable bias and imprecision. We aimed to provide a population pharmacokinetic (popPK) model of iohexol by re-evaluating data from the Berlin Initiative Study (BIS) to compare respective clearance estimates to the Schwartz approach and to assess the impact of revised clearance estimates on the BIS equations. A popPK model was developed based on iohexol plasma samples (8–10 per subject, iohexol dose 3235 mg) from 570 elderly patients. A three-compartment model appropriately described the pharmacokinetics of iohexol (clearance 57.4 mL/min, CV 33%). Compared to the three-compartment model, clearance values were overestimated by the Schwartz approach (bias 6.5 mL/min), resulting in limited effects on regression coefficients of the BIS equations (e.g., proportionality factor of BIS2 changed from 767 to 720). Predictions based on the BIS2 equation were biased (5.4 mL/min/1.73 m²) and the sensitivity to detect a GFR < 60 mL/min/1.73 m² was low compared to the revised equation (72% versus 89%). Three-compartment models should be employed to assess iohexol pharmacokinetics.

Estimated glomerular filtration rate in stable older kidney transplant recipients-are present algorithms valid? A national cross-sectional cohort study

Several equations have been developed for estimated glomerular filtration rate (eGFR) in patients with chronic kidney disease (CKD), but none were developed based on data from elderly kidney transplant recipients (KTR). The primary aim of this study was to evaluate different creatinine-based equations in stable elderly KTR. A national cross-sectional study was performed using data from 263 consecutive kidney transplant recipients 60 years or older who performed a routine GFR measurement one year after engraftment. GFR was measured by iohexol clearance calculation based on two samples. eGFR was calculated from a range of different creatinine-based equations using information obtained at the time of GFR measurement. Bias, precision, and accuracy were evaluated for each equation. All equations apart from Nankivell had accuracy (P30) > 80%. The BIS1, FAS, LMRCR , and Cockcroft & Gault equations in recipients older than 70 years and the FAS, LMRCR , and MDRD in recipients 60-69 years old had nonsignificant bias. The CKD-EPI had significant bias in both groups. If one should choose a single equation for follow-up of individual CKD progression in all recipients ≥ 60 years, the FAS or LMRCR equations are probably the best alternatives.

Assessment of renal function in geriatric palliative care patients - comparison of creatinine-based estimation equations.

BackgroundRenal function impairment is common in geriatric palliative care patients. Accurate assessment of renal function is necessary for appropriate drug dosage. Several equations are used to estimate kidney function.Aims1) To investigate the differences (Δ) in kidney function assessed with simplified Modifi-cation of Diet in Renal Disease (MDRD), Berlin Initiative Study (BIS1), and Cockcroft–Gault (C-G) formulas in geriatric palliative care patients, and 2) to assess factors that may influence these differences.MethodsA retrospective analysis of data of patients aged ≥70 years admitted to a palliative care in-patient unit. The agreement between C-G, MDRD, and BIS1 equations was assessed with Bland–Altman analysis. Partial correlation analysis was used to analyze factors influencing the discordance.ResultsA total of 174 patients (67 men; mean age 77.9±5.8 years) were enrolled. The mean Δ MDRD and C-G was 18.6 (95% limits of agreement 55.3 and −18.2). The mean Δ BIS1 and C-G was 6.1 (25.7 and −13.5), and the mean Δ MDRD and BIS1 was 12.5 (40.6 and −15.6). According to the National Kidney Foundation classification, 61 (35.1%) patients were differently staged using MDRD and C-G, whilê20% of patients were differently staged with BIS1 and C-G and MDRD and BIS1. Serum creatinine (SCr) and body mass index (BMI) had the most important influence on variability of Δ MDRD and C-G (partial R2 37.7% and 28.4%). Variability of Δ BIS1 and C-G was mostly influenced by BMI (34.8%) and variability of Δ MDRD and BIS1 by SCr (42.2%). Age had relatively low influence on differences between equations (3.1%–9.5%).ConclusionThere is a considerable disagreement between renal function estimation formulas, especially MDRD and C-G in geriatric palliative care patients, which may lead to errors in drug dosage adjustment. The magnitude of discrepancy increases with lower SCr, lower BMI, and higher age.

Estimation of the glomerular filtration rate in people older than 85: Comparisons between CKD-EPI, MDRD-IDMS and BIS1 equations

BackgroundThe evidence of glomerular filtration rate (GFR) estimating with serum creatinine based formulae in the elderly population is scarce. The purpose of this study is to compare CKD-EPI, MRD4-IDMS and BIS1 equations to analyze correlation and concordance in a population older than 85 years old. Patients and methodsWe designed a retrospective cross-sectional study, which included data from 600 patients older than 85 years. GFR was estimated by the following equations: CKD-EPI, MDR4-IDMS and BIS1, using as variables sex, age and serum creatinine concentration. Statistics analysis included Wilcoxon test, Bland–Altman plot, non-parametric Passing–Bablok method and kappa statistic (simple and weighted). ResultsThe patients’ median (range) age was 87 (interval 85–98). The median GFR (range) was 42.4 (5.2–127.4)mL/min/1.73m2, when it was estimated with MDRD-IDMS, 40.0 (4.5–93.1) for CKD-EPI and 36.9 (7.6–83.7) for BIS1. The comparison of BIS1 and CKD-EPI and MDRD-IDMS using the Wilcoxon test was significant (p<0.001). The regression analysis yielded the following equations: MDRD-IDMS=1.025×CKD-EPI+1.360; BIS1=0.688×CKD-EPI+9.074 and BIS1=0.666×MDRD-IDMS+8.401. The weighted coefficient was 0.958 for the concordance between MDRD-IDMS and CKD-EPI, 0.812 for the concordance between MDRD-IDMS and BIS1 and 0.846 for CKD-EPI and BIS1. ConclusionsThe GFR estimations obtained with BS1 equation are not interchangeable with MDRD-IDMS or CKD-EPI equations. BIS1 estimates lower GFR values than MDRD-IDMS and CKD-EPI and tends to classify the patients in a more advanced chronic kidney disease stage, especially for estimated GFR higher than 29mL/min/1.73m2.