Glomerular filtration rate equations overestimate creatinine clearance in older individuals enrolled in the Baltimore Longitudinal Study on Aging: impact on renal drug dosing

Renal function assessment in older people: comparative analysis of estimation equation with serum creatinine

Introduction

Age-related changes occurring in the kidney can lead to a reduction in Glomerular Filtration Rate (GFR); especially in older adults with multimorbidity and/or frailty, an accurate evaluation of kidney function is critical. For the estimation of GFR in patients over 70 years, CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) is often used. However, validated equations exist for old-age populations like BIS1 (Berlin Initiative Study 1) and FAS (Full Age Spectrum). Here we aimed to compare the performance of CKD-EPI, MDRD (Modification of Diet in Renal Disease), BIS1, and FAS in assessing eGFR in a population of patients over 70, to evaluate which equations show the most accurate performance in our setting.

Materials and methods

A total of 499 older adults were consecutively recruited in the Orthogeriatric ward and Oncogeriatrics clinic of IRCCS Polyclinic San Martino in Genoa Italy. eGFR was calculated using CKD-EPI, MDRD, BIS1, and FAS, calculating mean, median, standard deviation, and interquartile range. Bland-Altman graphs were used to evaluate how each equation performs with respect to the others and the concordance of the attribution of the KDIGO CKD stage was performed with Cohen's K constant and chi-squared test.

Results

Patients' mean age was 82.6 years (± 7.44), and the mean creatinine value was 0.97 (± 0.71) mg/dl. The mean value of eGFR was 70 mL/min with CKD-EPI (± 20.6) and MDRD (± 25.7), 57 mL/min with BIS1 (± 16.7) and FAS (± 19.0), respectively. BIS1 and FAS estimated lower eGFR values than CKD-EPI and MDRD. As age increases, a steady decrease in filtrate value is observed with BIS1 and FAS. MDRD and CDK-EPI do not show the same trend. The performance of the equations at a fixed eGFR value of 30 mL/min is more linear for BIS1 and FAS compared with CKD-EPI and MDRD. Upon evaluation with chi-square, the attribution of KDIGO stage was statistically different among the various equations.

Discussion

An appropriate assessment of renal function is of key clinical relevance to prevent adverse outcomes and risk of drug accumulation in older adults. Our study originally showed that in persons aged more than 70 years old BIS1 is the most accurate formula in calculating eGFR values when only serum creatinine is available.

Moving forward from Cockcroft-Gault creatinine clearance to race-free estimated glomerular filtration rate to improve medication-related decision-making in adults across healthcare settings: A consensus of the National Kidney Foundation Workgroup for Implementation of Race-Free eGFR-Based Medication-Related Decisions

PURPOSE

The goals of this paper are to (1) provide evidence and expert consensus to support a unified approach to estimating kidney filtration in adults with stable kidney function using race-free estimated glomerular filtration rate (eGFR) in place of Cockcroft-Gault estimated creatinine clearance (C-G eCrCL) for medical and medication-related decisions, and (2) demonstrate how adjusting eGFR results for an individual's body surface area (BSA) when it is higher or lower than 1.73 m2 will improve results for medication-related decisions.

SUMMARY

C-G eCrCL is predominantly used by US pharmacists to determine eGFR for the purposes of medication-related decisions, even though more accurate eGFR equations exist. Several driving factors make it the ideal time to shift clinical practice from using C-G eCrCL to eGFR. These factors include the following: (1) 2024 Food and Drug Administration (FDA) guidance for industry recommends eGFR over C-G eCrCL to evaluate the impact on pharmacokinetics in patients with impaired kidney function; (2) a joint National Kidney Foundation (NKF) and American Society of Nephrology task force recommends 3 race-free Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) eGFR equations for medical and medication-related decision-making; (3) the almost ubiquitous use of standardized serum creatinine assay methods in US clinical laboratories; and (4) increasing availability and use of serum cystatin C for eGFR assessment. This publication guides practitioners through the rationale for using race-free eGFR equations for medication-related decisions and how to implement this practice change.

CONCLUSION

The NKF Workgroup for Implementation of Race-Free eGFR-Based Medication-Related Decisions suggests that health systems, health settings, clinical laboratories, electronic health record systems, compendia and data vendors, and healthcare practitioners involved with medication-related decision-making transition away from C-G eCrCL and towards the race-free eGFR equations for more accurate assessment of kidney filtration and consistency in medication and medical decision-making across the US.

The impact of population ageing on the burden of chronic kidney disease

The burden of chronic kidney disease (CKD) and its risk factors are projected to rise in parallel with the rapidly ageing global population. By 2050, the prevalence of CKD category G3-G5 may exceed 10% in some regions, resulting in substantial health and economic burdens that will disproportionately affect lower-income countries. The extent to which the CKD epidemic can be mitigated depends largely on the uptake of prevention efforts to address modifiable risk factors, the implementation of cost-effective screening programmes for early detection of CKD in high-risk individuals and widespread access and affordability of new-generation kidney-protective drugs to prevent the development and delay the progression of CKD. Older patients require a multidisciplinary integrated approach to manage their multimorbidity, polypharmacy, high rates of adverse outcomes, mental health, fatigue and other age-related symptoms. In those who progress to kidney failure, comprehensive conservative management should be offered as a viable option during the shared decision-making process to collaboratively determine a treatment approach that respects the values and wishes of the patient. Interventions that maintain or improve quality of life, including pain management and palliative care services when appropriate, should also be made available.

Prevention of Chronic Kidney Disease and Its Complications in Older Adults

In an era marked by a global demographic shift towards an aging society, there is a heightened prevalence of chronic kidney disease (CKD) among older adults. The burden of CKD spans from kidney-related complications to impacting psychological well-being, giving rise to depressive symptoms and caregiver burnout. This article delves into CKD prevention strategies within the context of aging, contributing to the discourse by exploring its multifaceted aspects. The prevention of CKD in the older adults necessitates a comprehensive approach. Primary prevention is centered on the modification of risk factors, acknowledging the intricate interplay of various comorbidities. Secondary prevention focuses on early CKD identification. Tertiary prevention aims to address factors contributing to CKD progression and complications, emphasizing the importance of timely interventions. This comprehensive strategy aims to enhance the quality of life for individuals affected by CKD, decelerating the deterioration of functional status. By addressing CKD at multiple levels, this approach seeks to effectively and compassionately care for the aging population.

Differential Impact of the UNOS Simultaneous Liver-kidney Transplant Policy Change Among Patients With Sustained Acute Kidney Injury

BACKGROUND

Simultaneous liver-kidney transplant (SLK) allocation policy in the United States was revised in August 2017, reducing access for liver transplant candidates with sustained acute kidney injury (sAKI) and potentially adversely impacting vulnerable populations whose true renal function is overestimated by commonly used estimation equations.

METHODS

We examined national transplant registry data containing information for all liver transplant recipients from June 2013 to December 2021 to assess the impact of this policy change using instrumental variable estimation based on date of listing.

RESULTS

Posttransplant survival was compared for propensity-matched patients with sAKI who were only eligible for liver transplant alone (LTA_post; n = 638) after the policy change but would have been SLK-eligible before August 2017, with similar patients who were previously able to receive an SLK (SLK; n = 319). Overall posttransplant patient survival was similar at 3 y (81% versus 80%; P = 0.9). However, receiving an SLK versus LTA increased survival among African Americans (87% versus 61% at 3 y; P = 0.029). A trend toward survival benefit from SLK versus LTA, especially later in the follow-up period, was observed in recipients ≥ age 60 (3-y survival: 84% versus 76%; P = 0.2) and women (86% versus 80%; P = 0.2).

CONCLUSIONS

The 2017 United Network for Organ Sharing SLK Allocation Policy was associated with reduced survival of African Americans with end-stage liver disease and sAKI and, potentially, older patients and women. Our study suggested the use of race-neutral estimation of renal function would ameliorate racial disparities in the SLK arena; however, further studies are needed to reduce disparity in posttransplant outcomes among patients with liver and kidney failure.

The Ultrasound Renal Stress Test for the Assessment of Functional Renal Reserve in Kidney Transplantation: A Pilot Study in Living Donors

In the evolving landscape of nephrology and kidney transplants, assessing renal functional reserve (RFR) in living kidney donors is essential for ensuring donor safety and successful transplantation. This study explores the use of the Intra-Parenchymal Renal Resistive Index Variation (IRRIV) test, a novel non-invasive method, to measure RFR in living donors. Our observational study included 11 participants undergoing living kidney donations, evaluated using the IRRIV-based Renal Stress Test (RST) before and 12 months post-nephrectomy. The study demonstrated significant changes in creatinine and eGFR CKD-EPI levels post-donation, with an average creatinine rise from 69 to 97 µmol/L and a reduction in eGFR from 104 to 66 mL/min/1.73 m2. These variations align with the expected halving of nephron mass post-nephrectomy and the consequent recruitment of RFR and hyperfiltration in the remaining nephrons. This pilot study suggests that the IRRIV-based RST is a practical, safe, and reproducible tool, potentially revolutionizing the assessment of RFR in living kidney donors, with implications for broader clinical practice in donor eligibility evaluation, even in borderline renal cases. Furthermore, it confirms the feasibility of RST in living kidney donors and allows us to assess the sample size in 48 donors for a future study.

Albumin-bound kynurenic acid is an appropriate endogenous biomarker for assessment of the renal tubular OATs-MRP4 channel

Renal tubular secretion mediated by organic anion transporters (OATs) and the multidrug resistance-associated protein 4 (MRP4) is an important means of drug and toxin excretion. Unfortunately, there are no biomarkers to evaluate their function. The aim of this study was to identify and characterize an endogenous biomarker of the renal tubular OATs-MRP4 channel. Twenty-six uremic toxins were selected as candidate compounds, of which kynurenic acid was identified as a potential biomarker by assessing the protein-binding ratio and the uptake in OAT1-, OAT3-, and MRP4-overexpressing cell lines. OAT1/3 and MRP4 mediated the transcellular vectorial transport of kynurenic acid in vitro. Serum kynurenic acid concentration was dramatically increased in rats treated with a rat OAT1/3 (rOAT1/3) inhibitor and in rOAT1/3 double knockout (rOAT1/3-/-) rats, and the renal concentrations were markedly elevated by the rat MRP4 (rMRP4) inhibitor. Kynurenic acid was not filtered at the glomerulus (99% of albumin binding), and was specifically secreted in renal tubules through the OAT1/3-MRP4 channel with an appropriate affinity (Km) (496.7 μM and 382.2 μM for OAT1 and OAT3, respectively) and renal clearance half-life (t1/2) in vivo (3.7 ± 0.7 h). There is a strong correlation in area under the plasma drug concentration-time curve (AUC0-t) between cefmetazole and kynurenic acid, but not with creatinine, after inhibition of rOATs. In addition, the phase of increased kynurenic acid level is earlier than that of creatinine in acute kidney injury process. These results suggest that albumin-bound kynurenic acid is an appropriate endogenous biomarker for adjusting the dosage of drugs secreted by this channel or predicting kidney injury.

DOAC Dosing Discordance Using Different Estimates of Kidney Function and Outcomes

Direct oral anticoagulants (DOACs) are indicated for the prevention of stroke in nonvalvular atrial fibrillation. Although Food and Drug Administration labeling for DOACs uses estimated creatinine clearance according to the Cockcroft-Gault (C-G) equation, estimated glomerular filtration rate according to the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation is often reported. The objectives of this study were to evaluate DOAC dosing discordance and to determine whether discordance based on various estimates of kidney function is associated with bleeding or thromboembolism. The study was an institutional review board approved retrospective analysis of patients at UPMC Presbyterian Hospital from January 1, 2010, to December 12, 2016. Data were obtained through electronic medical records. Adults who received a medication charge for rivaroxaban or dabigatran, had a diagnosis code for atrial fibrillation, and had a serum creatinine within 3 days of DOAC initiation were included. Doses were considered discordant if the calculated dose based on CKD-EPI did not match the patient's dose during index admission, if dosed correctly using C-G. Association of discordance with dabigatran, rivaroxaban, and clinical outcomes was determined using odds ratios and 95% confidence intervals. Rivaroxaban discordance was present among 49 of the 644 (8%) patients who were dosed correctly with C-G. Dabigatran discordance was present among 17 of the 590 (3%) patients who were dosed correctly. Discordance with rivaroxaban was found to increase the risk of thromboembolism when using CKD-EPI (odds ratio, 2.83; 95% CI, 1.02-7.79, P = .045) versus C-G. Our findings emphasize the need to dose DOACs, specifically rivaroxaban, appropriately in patients with nonvalvular atrial fibrillation.

Comparison of creatinine-based equations for estimating renal function for digoxin dose adjustment in patients with atrial fibrillation and heart failure

The aim of this study was to determine an appropriate equation for estimating renal function to dose regulate the serum digoxin trough concentration to a target of <0.9 ng/ml in patients with atrial fibrillation (AF) and heart failure (HF). All patients received 0.125 mg oral digoxin daily. The estimated glomerular filtration rate by the Modification of Diet in Renal Disease (eGFRMDRD ) equation deindexed based on body surface area had the highest correlation with digoxin trough concentrations (r = -0.450) compared to the Cockcroft-Gault equation (r = -0.415) or deindexed eGFR based on the Chronic Kidney Disease Epidemiology Collaboration (eGFRCKD-EPI ) equation (r = -0.416). The median digoxin trough concentrations were 0.60, 0.77, 0.97 and 1.30 ng/ml in patients with a deindexed eGFRMDRD  ≥ 60, 45-59, 30-44 and < 30 ml/min, respectively. The deindexed eGFRMDRD is an appropriate equation for digoxin dose adjustment in patients with AF and HF.

The Eucalcemic Patient With Elevated Parathyroid Hormone Levels

Primary hyperparathyroidism (PHPT) is classically characterized by hypercalcemia with elevated or inappropriately normal parathyroid hormone (PTH) levels. Elevated PTH levels in the presence of normal calcium levels are not infrequently found during the evaluation of metabolic bone disorders or kidney stone disease. This can be caused by secondary hyperparathyroidism (SHPT) or normocalcemic primary hyperparathyroidism (NPHPT). NPHPT is due to autonomous parathyroid function whereas SHPT is caused by a physiologic stimulation to PTH secretion. Many medical conditions and medications can contribute to SHPT, and differentiation between SHPT and NPHPT may be difficult. Cases are presented to illustrate examples. In this paper, we review the distinction between SHPT and NPHPT as well as end organ effects of NPHPT and outcomes of surgery in NPHPT. We suggest that the diagnosis of NPHPT be made only after careful exclusion of causes of SHPT and consideration of medications that can increase PTH secretion. Further, we advise a conservative approach to surgery in NPHPT.

Older Women Who Practiced Physical Exercises before the COVID-19 Pandemic Present Metabolic Alterations and Worsened Functional Physical Capacity after One Year of Social Isolation

Background: Because the consequences of the lifestyle changes in older adults associated with the social isolation imposed in response to the COVID-19 pandemic are not fully understood, here, we investigated the effects of one year of social isolation imposed by COVID-19 on the metabolic parameters and functional physical capacity of older women who regularly practiced physical exercises before the pandemic. Methods: Systemic lipid and protein profiles, estimated creatinine clearance (ECC), and functional physical capacity (FPC) were assessed before (January-February 2020) and 12 months after social isolation in 30 older women (mean age 73.77 ± 6.22) who were engaged in a combined-exercise training program for at least 3 years before the COVID-19 pandemic. Results: In this group, we observed increased plasma levels of triglycerides and creatinine, an increase in the time necessary to perform gait speed and time-up-and-go tests, and reduced muscle strength assessed by the handgrip test and ECC post-COVID-19 pandemic relative to values recorded pre-pandemic. In addition, we observed significant correlations (both negative and positive) between anthropometric, some metabolic parameters, and physical tests. Conclusion: One year of interruption of physical exercise practice imposed in response to the COVID-19 pandemic significantly altered some systemic metabolic parameters and worsened ECC and FPC in older women.

Kidney Function Assessment in African American Patients: A Narrative Review for Pharmacists

Recent recognitions of longstanding societal inequity in kidney function assessments have prompted the call to eliminate race as part of the algorithm to assess estimated glomerular filtration rate (eGFR). Previous equations for eGFR estimation adopted race as part of the calculation. Incorporating race within eGFR equations results in overestimating and underestimating Black and nonblack patients, respectively. The inclusion of race is controversial. In September 2021, the National Kidney Foundation (NKF) and the American Society of Nephrology (ASN) combined task force recommended estimating the kidney function without using a race variable. The task force endorsed race-free creatinine-cystatin C equations to be more accurate than the creatinine-only equations. Before the application of NKF-ASN revised recommendations, major healthcare disparities influenced daily clinical practice. Those disparities include the delay in initiating medications that have reanl or cardio-protective effects, such as sodium-glucose cotransporter–2 inhibitors (SGLT-2i) and angiotensin-converting enzyme inhibitors (ACEIs). Clinical judgment should be employed when dose adjusting medications. Combining the eGFR with other clinical assessment tools such as urinary output, the expanded use of confirmatory tests, and the eGFR trend is suggested for a better kidney function assessment. Additionally, creatinine-cystatin C is recommended when feasible, and when institutions have the laboratory abilities.

The removal of race from kidney function estimation: Key points for primary providers

Recent recognitions of longstanding societal effects of structural and overt acts of racism have led to calls for the elimination of race, a social construct, from medical algorithms. This accelerated a growing concern with the use of race in kidney function estimating equations. A task force sponsored by the two leading nephrology societies in the United States has reassessed the inclusion of race in glomerular filtration rate (GFR) estimation and recently put forth recommendations. New race-free equations have been developed and guides for widespread implementation have been provided. We herein review the journey of kidney function estimating equations, race in GFR estimating equations, new race-free equations and the path forward in caring for chronic kidney disease. We urge upon all primary care providers to employ concerted focus on early detection and identification of kidney dysfunction as well as risk factors including social determinants of health to prevent progression.

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

Background

According 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.

Objective

This 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.

Methods

A 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.

Results

Depending 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.

Conclusion

Despite 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.

Impact of Recent Acute Kidney Injury on Creatinine Clearance Estimation in Critically Ill Patients Undergoing Cardiac Surgery

Acute kidney injury (AKI), often present in critically ill patients and patients with cardiac dysfunction, may alter estimates of renal function. The impact of recent AKI on the accuracy of the Cockcroft-Gault creatinine clearance equation (CG-CrCl) before cardiac surgery is unknown. This single-center, retrospective study included patients who underwent cardiac surgery from 1 January 2006 through 30 June 2012 and whose 24-hour urine creatinine clearance (24hr-CrCl) was measured in the intensive care unit before surgery. We evaluated CG-CrCl accuracy by calculating absolute differences between 24hr-CrCl and CG-CrCl estimates. Clinical impact was signified by discrepancies in United States Food and Drug Administration (FDA) renal impairment stage indicated by 24hr-CrCl versus CG-CrCl estimates. Acute kidney injury was evaluated by using Kidney Disease: Improving Global Outcomes criteria. Of 161 patients, 93 (58%) had recent AKI: stage 1, 31 (33%); stage 2, 39 (42%); and stage 3, 23 (25%). In mL/min, the CG-CrCl overestimated 24hr-CrCl (absolute difference: total, -10 ± 25; no AKI, -7 ± 26; stage 1, -8 ± 17; stage 2, -16 ± 28; and stage 3, -10 ± 26; P=0.29). Renal impairment stages assigned by CG-CrCl did not match 24hr-CrCl in 70 (43%) of the 161 patients, especially those with recent AKI: no AKI, 24/68 (35%); stage 1, 13/31 (42%); stage 2, 23/39 (59%); and stage 3, 10/23 (43%). The CG-CrCl consistently overestimated 24hr-CrCl in critically ill patients before cardiac surgery. Clinicians should use the CG-CrCl cautiously when estimating renal function and medication dosages in this population.

Optimized Dosing: The Next Step in Precision Medicine in Non-Small-Cell Lung Cancer

In oncology, and especially in the treatment of non-small-cell lung cancer (NSCLC), dose optimization is often a neglected part of precision medicine. Many drugs are still being administered in "one dose fits all" regimens or based on parameters that are often only minor determinants for systemic exposure. These dosing approaches often introduce additional pharmacokinetic variability and do not add to treatment outcomes. Fortunately, pharmacological knowledge is increasing, providing valuable information regarding the potential of, for example, therapeutic drug monitoring. This article focuses on the evidence for the most promising and easily implemented optimized dosing approaches for the small-molecule inhibitors, chemotherapeutic agents, and monoclonal antibodies as treatment options currently approved for NSCLC. Despite limitations such as investigations having been conducted in oncological diseases other than NSCLC or the retrospective origin of many analyses, an alternative dosing regimen could be beneficial for treatment outcomes, prescriber convenience, or financial burden on healthcare systems. This review of the literature provides recommendations on the implementation of dose optimization and advice regarding promising strategies that deserve further research in NSCLC.

Correlation of Measured and Estimated Creatinine Clearance in Hospitalized Elderly Patients: A Retrospective Cohort Study

Background: Accurate assessment of renal function is essential in hospitalized elderly patients. Few studies have examined the accuracy of Cockcroft-Gault (C-G) estimates of creatinine clearance (CrCl) compared with measured clearance in these patients. Objective: The objective of this study was to determine the correlation between C-G estimates of CrCl and measured CrCl in hospitalized elderly patients. Methods: This Institutional Review Board-approved, single-center retrospective observational cohort study included all patients who were 65 years and older admitted to our medical center in January to September 2018 with either an 8- or 24-hour urine collected during admission. The primary outcome was correlation, bias, and precision of C-G estimates of CrCl versus measured CrCl using Pearson correlation, Spearman linear regression, and Bland-Altman analysis. Outliers were determined using a cut-off of ±20%. Data are presented as median (interquartile range) or percentages. Results: A total of 108 urine collections from 90 unique patients were included in the study. The patients were 51% female, median age was 71 (68-77) years, and median body mass index was 26.6 (22.8-31) kg/m². Most collections were over 24 hours (66.7%), and 38% were performed while patients were in an intensive care unit. Median blood urea nitrogen (BUN) was 24.5 (17-36) mg/dL and median serum creatinine was 0.71 (0.55-1.09) mg/dL. The median C-G estimation was 75.4 (48.2-110.6) mL/min, and the median measured CrCl was 79.1 (38.1-99.5) mL/min, r ² = .56 (P < .001). Bland-Altman analysis showed large limits of agreement (-75.5-57.7 mL/min), with a bias of -8.9 and precision (standard deviation of bias) of 34 mL/min. Outliers were common, with 38% of C-G estimation values >120% of measured CrCl, and 18% of C-G estimates <80% of measured CrCl. Conclusions: Measured CrCl varied significantly from C-G estimates in hospitalized elderly patients. It is important to recognize characteristics of patients who may benefit from measurement of CrCl. Future studies should examine the impact of this variance on clinical outcomes.

Drug-Related Problems in Hospitalised Patients with Chronic Kidney Disease: A Systematic Review

INTRODUCTION

Globally, chronic kidney disease (CKD) is one of the leading causes of mortality. Impaired renal function makes CKD patients vulnerable to drug-related problems (DRPs).

AIM

The aim of this systematic review was to investigate the prevalence and nature of DRPs among hospital in-patients with CKD.

METHODS

A systematic review of the literature was conducted using Medline, EMBASE, PsycINFO, Web of Science (Core Collection), CINAHL plus (EBSCO), Cochrane Library (Wiley), Scopus (ELSEVIER) and PubMed (U.S.NLM) from index inception to January 2020. Studies investigating DRPs in hospitalised CKD patients published in the English language were included. Two independent reviewers extracted the data and undertook quality assessment using the Joanna Briggs Institute (JBI) tool.

RESULTS

A total of 2895 unique titles were identified; with 20 meeting the inclusion criteria. DRPs prevalence in CKD was reported between 12 and 87%. The most common DRPs included ineffective treatment, inappropriate drug choice and dosing problems. Antibiotics, H2-antihistamines and oral antidiabetics (metformin) were common drug classes involved in DRPs. Factors associated with DRPs included severity of CKD, the number of medications taken, age, length of hospital stay, and gender.

CONCLUSION

This systematic review provides evidence that DRPs are a frequent occurrence and burden for hospitalised patients with stage 1-4 CKD. Heterogeneity in study design, case detection and definitions are common, and future studies should use clearer definitions and study designs. Protocol Registration: PROSPERO: CRD42018096364.

[Estimation of glomerular filtration rate in the elderly patient: Clinical implications in the use of antibiotics]

INTRODUCTION

In elderly, impaired kidney function may lead to relevant clinical implications, especially in drug dosage. There is no consensus on the best formula to estimate glomerular filtration rate (GFR) in this context. While the Cockcroft-Gault (CG) equation is the most used one in drug development, the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation is the most employed by clinical laboratories. The objective of this study is to analyze the differences and implications of using one or another equation when adjusting the dose of antibiotics.

MATERIAL AND METHODS

Cross-sectional study performed in patients older than 80 years admitted to an acute geriatric unit for infectious disease. Socio-demographic, functional, clinic, assistance and laboratory variables were gathered, calculating GFR according to CG and CKD-EPI. A concordance study between both equations, bivariate analysis and multiple linear regression were carried out.

RESULTS

100 patients were recruited, with mean age 88.5±4.2 years, and 54% women. A relative overestimation of 13.63mL/min was observed in GFR according to CKD-EPI, with a low-moderate concordance between both formulas. Greater need for dose adjustment of antibiotics with GC than with CKD-EPI was detected (38% vs. 23%; P<.001), as well as dosage discrepancies, especially with levofloxacin.

CONCLUSIONS

Both equations are not interchangeable in the elderly. When used to adjust antibiotic dose, CKD-EPI may overestimate GFR and may cause an increase in adverse reactions. Further studies should be carried out with the aim of reaching a consensus on the most appropriate equation for the elderly patient.

Impacts of COVID-19 Pandemic on Psychological Well-Being of Older Chronic Kidney Disease Patients

COVID-19 pandemic has been a major global issue, its eventual influences on the population welfare, global markets, public security, and everyday activities remain uncertain. Indeed, the pandemic has arisen a significant global threat. Its psychological impact is predicted to be severe and enduring, but the absolute magnitude is still largely unclear. Chronic kidney disease (CKD) is a complication markedly contributes to the mortality of COVID-19 cases, meanwhile several studies have demonstrated the high frequency and seriousness of the COVID-19 in CKD patients receiving dialysis. Importantly, the influence of COVID-19 among CKD patients without dialysis is still largely unexplored. Thus, we systemically summarized how mental health affects the spreading of COVID-19 to virtually worldwide, covering perspectives from several countries across a wide range of fields and clinical contexts. This review aims to provide the latest details and reveal potential concerns on the public health including psychological well-being of the older patients with CKD.

Population Pharmacokinetic Analysis and Dosing Optimization Based on Unbound Daptomycin Concentration and Cystatin C in Nonobese Elderly Patients with Hypoalbuminemia and Chronic Kidney Disease

PURPOSE

This study evaluated the population pharmacokinetics of daptomycin in nonobese elderly patients with hypoalbuminemia and chronic kidney disease (CKD) using the glomerular filtration rate estimated from cystatin C (eGFRcys) and estimated its optimal dose.

METHODS

We performed population pharmacokinetic analysis of the unbound concentrations of daptomycin. The probability of target attainment of 90% for achieving an area under the concentration-time curve of unbound daptomycin at steady state/ minimum inhibitory concentration ratio of ≥66.6 was stochastically simulated.

RESULTS

In the population pharmacokinetic analysis of 25 patients aged ≥65 years, the two-compartment model using eGFRcys and age as covariates of clearance in central compartment of unbound daptomycin were optimal. The unbound fraction rate (fu) was 0.05-0.14. According to the Monte Carlo simulation, the optimal doses for patients with eGFRcys of 20-60 mL/min and aged 65-95 years were calculated as 200-500 mg q24h.

CONCLUSION

These results suggest that establishing the dose using total concentrations may result in under- or overestimation caused by alterations in fu. The optimal dose for nonobese elderly patients with hypoalbuminemia and CKD depends on eGFRcys and age, and a standard dose may be insufficient for some patients.

Deviant Dosing: A Post hoc Analysis of Pharmacist Characteristics Related to Renal Dosing Decisions

BACKGROUND

A recent study demonstrated that pharmacists presented with multiple estimating equations deviated from recommended dosing guidance more often than pharmacists who were presented with a single estimate on clinical vignettes.

OBJECTIVES

To identify characteristics associated with an increased tendency to deviate from approved recommendations.

METHODS

Participant data were split into 2 cohorts: pharmacists who chose a dose that was inconsistent with dosing recommendations on at least 1 of the 4 vignettes and pharmacists who did not deviate on a single case. Bivariate analysis of demographic- and practice-related variables were conducted between groups using the χ², Mann-Whitney U, or Student t-test for nominal, ordinal, and continuous variables, respectively. Statistically different covariates between groups (P < 0.05) were assessed using multivariable linear regression.

RESULTS

Survey data from 154 inpatient pharmacists, 71 of whom deviated on at least 1 clinical vignette, were analyzed. On univariate analysis, deviator pharmacists were more likely to have completed postgraduate residency training (68% vs 41%; P < 0.05) and board certification (39% vs 20%; P < 0.05). Deviator pharmacists were also more likely to have been presented with multiple renal estimates as opposed to a single estimate and had differing renal dosing practices at baseline (P < 0.05). Following multivariable regression, residency training, mismatched baseline renal practices, and multiple renal estimates remained independent predictors (P < 0.05) of dosing deviation.

CONCLUSION AND RELEVANCE

Higher clinical training, practice variation, and multiple renal estimates may affect renal dosing practices. Prospective, statistically powered studies are needed to verify these hypotheses.

Oral anticoagulation in chronic kidney disease with atrial fibrillation

Chronic kidney disease (CKD) and atrial fibrillation (AF) frequently coexist, amplifying the risk of cardiovascular events and mortality. In patients with CKD stage 3 and non-valvular AF, direct oral anticoagulants (DOACs) have shown, compared to vitamin K antagonists (VKA), equal or greater efficacy in the prevention of stroke and systemic embolism, and greater safety. There are no randomizedtrials of the efficacy and safety of DOACs and VKA in advanced CKD. On the other hand, observational studies suggest that DOACs, compared to warfarin, are associated with a lower risk of acute kidney damage and generation/progression of CKD. This paper reviews the epidemiological and pathophysiological aspects of the CKD and AF association, the evidence of the efficacy and safety of warfarin and ACODs in various stages of CKD with AF as well as the comparison between warfarin and ACODs in efficacy and anticoagulant safety, and in its renal effects.

Chronic Abdominal Pain in General Practice

Background and Summary: Chronic abdominal pain is a challenging complaint for both primary care providers and gastroenterologists alike, due to a broad differential diagnosis and sometimes extensive and negative workup. In the absence of red flag features that herald more acute conditions, the majority of patients with chronic abdominal pain have a benign cause or a functional disorder (e.g., irritable bowel syndrome). The costs associated with a diagnostic workup are an expensive burden to health care. A systematic approach for evaluating patients and initiating a management plan are recommended in the primary care setting. Undiagnosed abdominal pain should be investigated starting with a detailed history and physical examination. Diagnostic investigations should be limited and adapted according to the clinical features, the alarm symptoms, and the symptom severity. This review will focus on the diagnostic tools which general practitioners utilize in the evaluation of chronic abdominal pain. Key Messages: The primary role of the general practitioner is to differentiate an organic disease from a functional one, to refer to a specialist, or to provide treatment for the underlying cause of pain. The functional disorders should be considered after the organic pathology has been confidently excluded. Once a diagnosis of functional pain is established, repetitive testing is not recommended and the patient should be referred to receive psychological support (e.g., cognitive therapy) associated with available pharmacological therapeutic options.

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.

Predictive Value of Creatinine-based Equations of Kidney Function in the Long-term Prognosis in United Arab Emirates Patients

Objectives

Chronic kidney disease (CKD) is an independent predictor of mortality. Several creatinine-based equations are used to assess the estimated glomerular filtration rate or creatinine clearance and mortality prediction in various ethnic populations. Similarly, renal insufficiency is associated with poor prognosis of UAE nationals with cardiovascular disease (CVD) risk factors. However, the equation that best assesses prognosis among these patients is unknown. This study aimed to compare the prognostic abilities of different creatinine-based kidney function equations for predicting all-cause mortality in UAE nationals with vascular comorbidities.

Methods

This retrospective observational study analyzed 1186 patients (54.0% men) with CVD risk factors. Multivariable Cox regression analysis was used to evaluate the associations of categorical renal function stages with all-cause mortality. Measures of performance in each equation assessed with respect to all-cause mortality were evaluated and compared to the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation by calculating the C-index, net reclassification index (NRI), and integrated discrimination index.

Results

Over a median follow-up of 8.9 years, the cumulative incidence of all-cause mortality was 9.4% (n = 112). After multivariable adjustment, the discriminative ability for all-cause mortality was significantly higher in the body surface area-adjusted Cockcroft-Gault (BSA-CG) formula than in the CKD-EPI equation (C-indices: 0.869 vs. 0.861, respectively, p = 0.037). NRI was significantly positive and favored the BSA-CG formula (0.54; 95% confidence interval: 0.35–0.64) compared to the CKD-EPI equation.

Conclusions

Our findings suggest that the BSA-CG equation may have the potential to slightly improve mortality prediction compared to the CKD-EPI equation in UAE nationals with vascular risk. Further large multicenter studies are warranted to confirm our findings.

Position paper on the safety/efficacy profile of direct oral anticoagulants in patients with chronic kidney disease. Consensus document from the SIN, FCSA and SISET

Direct oral anticoagulants (DOAC) are mostly prescribed to prevent cardioembolic stroke in patients with non-valvular atrial fibrillation (AF). An increasing number of guidelines recommend DOAC in AF patients with preserved renal function for the prevention of thromboembolism, and an increased use of DOAC in daily practice has been recorded also in elderly patients. Ageing is associated with a reduction in glomerular filtration rate, and impaired renal function, regardless of the cause, increases the risk of bleeding. Multiple medication use (polypharmacy) for treating superimposed co-morbidities is common in both elderly and chronic kidney disease (CKD) patients and drug-drug interaction may cause accumulation of DOAC, thereby increasing the risk of bleeding. The safety profile of DOAC in patients with CKD has not been defined with any certainty, particularly in those with severely impaired renal function or end stage renal disease. This has been due to the heterogeneity of studies and the relative paucity of data. This document reports the position of three Italian scientific societies engaged in the management of patients with atrial fibrillation who are treated with DOAC and present with CKD.

Accuracy of freely available online GFR calculators using the CKD-EPI equation

Purpose

Estimated glomerular filtration rate (eGFR) as calculated by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation is used for detection of chronic kidney disease and drug dose adjustment. The purpose of the present study was to investigate the accuracy of freely available eGFR online calculators.

Methods

All identified CKD-EPI online calculators were run with five reference cases differing in age, sex, serum creatinine, and ethnicity. Conversion from eGFR_indexed (unit ml/min per 1.73 m²) to eGFR_non-indexed (unit ml/min) and creatinine unit from milligramme/decilitre to micromole/litre was checked, if available.

Results

Only 36 of 47 calculators (76.6%) produced accurate eGFR results for all reference cases. Eight of 47 (17.0%) calculators were considered as faulty because of errors relating to ethnicity (4 calculators), to conversion of the eGFR unit (2 calculators), to erroneous eGFR values without obvious explanation (2 calculators), to conversion of the creatinine unit (1 calculator), and to an error in the eGFR unit displayed (1 calculator). Overall, 28 errors were found (range 59 to 147% of the correct eGFR value), the majority concerning calculation of eGFR_indexed and the conversion to eGFR_non-indexed. Only 7 of 47 (14.9%) calculators offered conversion of the eGFR unit.

Conclusions

Erroneous calculations that might lead to inappropriate clinical decision-making were found in 8 of 47 calculators. Thus, online calculators should be evaluated more thoroughly after implementation. Conversion of eGFR units that might be needed for drug dose adjustments should be implemented more often.

Electronic supplementary material

The online version of this article (10.1007/s00228-020-02932-x) contains supplementary material, which is available to authorized users.

Longitudinal Change in Cortisol Levels Across the Adult Life Span

BACKGROUND

Cortisol is a key stress hormone implicated in the pathogenesis of many age-related diseases. Longitudinal information on cortisol exposure has been restricted to animal models and a small number of human studies. The purpose of the present study was to quantify longitudinal change in cortisol across the adult life span.

METHODS

We conducted a prospective longitudinal study of 24-hour urinary free cortisol excretion from ages 20 to 90 years and older. Participants were 1,814 men and women from the Baltimore Longitudinal Study of Aging who provided a total of 5,527 urine specimens for analysis. The average duration of longitudinal follow-up was 6.6 years. The primary outcome measure was 24-hour urinary free cortisol to creatinine ratio (UFC/Cr) as determined by liquid chromatography/mass spectrometry.

RESULTS

UFC/Cr follows a U-shaped pattern across the life span with decreases in UFC/Cr in the 20s and 30s, relative stability in the 40s and 50s, and increases thereafter. This pattern of change was robust with respect to adjustment for several potential confounding factors.

CONCLUSIONS

Age-related changes in cortisol exposure raise important questions about the potential protective or exacerbating role of cortisol exposure in predicting medical, physiological, and behavioral outcomes.

Population Pharmacokinetic Study of Ceftriaxone in Elderly Patients, Using Cystatin C-Based Estimates of Renal Function To Account for Frailty

Ceftriaxone is widely used for respiratory and urinary infections in elderly and frail patients, but there are few pharmacokinetic studies. A prospective population pharmacokinetic study of ceftriaxone in adults over 65 years old was undertaken. Dried blood spots collected at baseline (predose) and 0.5, 1, 4, 8, and 24 h after administration of 1 g of ceftriaxone were assayed using a validated liquid chromatography-mass spectroscopy analytical method. Frailty was classified using the Edmonton frailty scale and grip strength via a hand dynamometer. Estimates of glomerular filtration rate were determined using creatinine-based and cystatin C-based equations. Of 26 patients recruited, 23 (88%) were vulnerable or very frail. Estimates of drug clearance improved significantly with a cystatin C-based estimate of renal function that accounted for frailty. Simulations indicate that the combined effects of ranges of size and renal function resulted in a 6-fold range in peak ceftriaxone concentrations and 9-fold range in total exposure (area under the concentration-time curve [AUC]). For elderly patients with moderate or severe renal impairment, 48-h dosing results in greater trough concentrations and total exposure than the trough concentrations and total exposure in patients with normal renal function receiving 24-h dosing. Cystatin C-based measures of renal function improved predictions of ceftriaxone clearance in elderly patients.

Position paper on the safety/efficacy profile of Direct Oral Anticoagulants in patients with Chronic Kidney Disease: Consensus document of Società Italiana di Nefrologia (SIN), Federazione Centri per la diagnosi della trombosi e la Sorveglianza delle terapie Antitrombotiche (FCSA) and Società Italiana per lo Studio dell'Emostasi e della Trombosi (SISET)

Direct oral anticoagulants (DOAC) are mostly prescribed to prevent cardioembolic stroke in patients with non-valvular atrial fibrillation (AF). An increasing number of guidelines recommend DOAC in AF patients with preserved renal function for the prevention of thromboembolism and an increased use of DOAC in daily practice is recorded also in elderly patients. Aging is associated with a reduction of glomerular filtration rate and impaired renal function, regardless of the cause, increases the risk of bleeding. Multiple medication use (polypharmacy) for treating superimposed co-morbidities is common in both elderly and chronic kidney disease (CKD) patients and drug-drug interaction may cause accumulation of DOAC, thereby increasing the risk of bleeding. There is uncertainty on the safety profile of DOAC in patients with CKD, particularly in those with severely impaired renal function or end stage renal disease, due to the heterogeneity of studies and the relative paucity of data. This document reports the position of three Italian scientific societies engaged in the management of patients with atrial fibrillation who are treated with DOAC and present with CKD.

The relationship between intra-parenchymal renal resistive index variation and renal functional reserve in healthy subjects

BACKGROUND

Renal functional reserve can be used as a clinical tool for risk stratification of patients undergoing potentially nephrotoxic procedures. Ultrasound assessment of intra-parenchymal renal resistive index variation-IRRIV test-has been recently proposed as a safe, reproducible, inexpensive and easy to perform technique to identify the presence of renal functional reserve. The present study has been designed to externally validate the IRRIV test in a validation cohort of healthy subjects.

METHODS

We examined data from a group of 47 healthy subjects undergoing protein loading and IRRIV testing. The correlation between IRRIV and renal functional reserve was tested using Pearson correlation analysis. Concordance between presence of renal functional reserve (i.e. a value of renal functional reserve ≥ 15 ml/min/1.73 m²) and IRRIV was evaluated using logistic regression analysis.

RESULTS

We found a significant correlation between IRRIV and renal functional reserve (Pearson correlation coefficient = 0.83 [95% confidence interval (CI) 0.71-0.90; p < 0.01]). Concordance between the presence of renal functional reserve and the IRRIV test was described in 45 (95.7%) subjects. In particular, a negative IRRIV test correctly predicted the absence of renal functional reserve in 5 subjects, while a positive IRRIV test correctly predicted the presence of renal functional reserve in 40 subjects. Only two subjects were incorrectly classified by the IRRIV test. IRRIV predicts renal functional reserve with a ROC-AUC of 0.86 [CI 95% 0.68-1].

CONCLUSIONS

The IRRIV test is an ultrasound technique that significantly predicts the presence and the degree of renal functional reserve in healthy subjects.

The Impact of Multiple Renal Estimates on Pharmacist Dosing Recommendations: A Randomized Trial

Background:

Numerous equations are used for estimation of renal function, and many electronic medical records report multiple clearance estimates to assist with drug dosing. It is unknown whether the presence of multiple clearance estimates affects clinical decision-making.

Objective:

To determine whether the presence of multiple renal clearance estimates affects pharmacist drug dosing decisions.

Methods:

A randomized trial in the form of an electronic survey including 4 clinical vignettes was delivered to hospital pharmacists. Vignettes consisted of a patient presenting with an acute pulmonary embolism requiring enoxaparin therapy. Pharmacists were randomized to receive a single estimate of renal function or multiple estimates for all vignettes. The primary outcome was deviation from approved recommendations on at least 1 vignette. The χ2 test was used to detect differences in deviation rates between groups. Logistic regression was performed to adjust for the effects of potentially confounding variables.

Results:

A total of 154 studies were completed (73 in the multiple-estimate group and 81 in the single-estimate group). Pharmacists presented with multiple renal estimates were significantly more likely to deviate from recommended dosing regimens than pharmacists presented with a single estimate (54.7% vs 38.2%; P = 0.04). The results were driven primarily by the 2 vignettes that included discordance among Cockcroft-Gault equation creatinine clearance estimates. Logistic regression identified multiple estimates as the only independent predictor of deviation ( P = 0.04).

Conclusion and Relevance:

Pharmacists provided with a single renal clearance estimate were more likely to adhere to approved dosing recommendations than pharmacists provided with multiple estimates.

Clearance Confusion: An Exploratory Analysis of Inpatient Dosing Discordances Between Renal Estimating Equations

Background:

Numerous equations exist for estimating renal clearance for drug dosing, and discordance rates may be as high as 40% in certain populations. However, the populations and types of equations used in these studies may not be generalizable to broader pharmacy practice.

Objectives:

To determine the dosing discordance rate between Cockcroft-Gault (C-G), Chronic Kidney Disease Epidemiology (CKD-EPI), and Modification of Diet in Renal Disease (MDRD) equations in a community hospital population.

Methods:

This was a cross-sectional analysis of inpatients who had documented renal function assessment over a 6-month period. Renal estimation was calculated using 5 equations (MDRD, CKD-EPI, and 3 C-G variants). Differences between equations were assessed using mean bias, dosing discordance, and agreement (κ statistic). Patients with acute kidney injury and those requiring renal replacement therapy were excluded.

Results:

A total of 466 patients were eligible for inclusion. Dosing discordance was evident between C-G variants and both MDRD and CKD-EPI equations in greater than 20% of patients. Agreement was highest between MDRD and CKD-EPI (κ = 0.93) and lowest between MDRD and C-G calculated using ideal body weight (κ = 0.33). The majority of discordant instances led to higher dosing recommendations when using MDRD and CKD-EPI equations compared with C-G variants. Dosing discordance exceeded 18% between the different C-G variants, with the highest discordance (36%) observed between total body weight and ideal body weight variants.

Conclusion and Relevance:

Dosing discordance between renal estimating equations is widespread. Practitioners and institutions should be aware of these differences when dosing medications and implementing renal dosing policies.

A roadmap to build a phenotypic metric of ageing: insights from the Baltimore Longitudinal Study of Aging

Over the past three decades, considerable effort has been dedicated to quantifying the pace of ageing yet identifying the most essential metrics of ageing remains challenging due to lack of comprehensive measurements and heterogeneity of the ageing processes. Most of the previously proposed metrics of ageing have been emerged from cross-sectional associations with chronological age and predictive accuracy of mortality, thus lacking a conceptual model of functional or phenotypic domains. Further, such models may be biased by selective attrition and are unable to address underlying biological constructs contributing to functional markers of age-related decline. Using longitudinal data from the Baltimore Longitudinal Study of Aging (BLSA), we propose a conceptual framework to identify metrics of ageing that may capture the hierarchical and temporal relationships between functional ageing, phenotypic ageing and biological ageing based on four hypothesized domains: body composition, energy regulation, homeostatic mechanisms and neurodegeneration/neuroplasticity. We explored the longitudinal trajectories of key variables within these phenotypes using linear mixed-effects models and more than 10 years of data. Understanding the longitudinal trajectories across these domains in the BLSA provides a reference for researchers, informs future refinement of the phenotypic ageing framework and establishes a solid foundation for future models of biological ageing.

Considerations for the optimal management of antibiotic therapy in elderly patients

OBJECTIVES

To maximise efficacy and minimise toxicity, special considerations are required for antibiotic prescription in elderly patients. This review aims to provide practical suggestions for the optimal management of antibiotic therapy in elderly patients.

METHODS

This was a narrative review. A literature search of published articles in the last 15 years on antibiotics and elderly patients was performed using the Cochrane Library and PubMed electronic databases. The three priority areas were identified: (i) pharmacokinetics/pharmacodynamics (PK/PD) for optimising dosage regimens and route of administration; (ii) antibiotic dosages in some special subpopulations; and (iii) treatment considerations relating to different antibiotic classes and their adverse events.

RESULTS

Clinicians should understand the altered PK/PD of drugs in this population owing to co-morbid conditions and normal physiological changes associated with ageing. The body of evidence justifies the need for individualised dose selection, especially in patients with impaired renal and liver function. Clinicians should be aware of the major drug-drug interactions commonly observed in the elderly as well as potential side effects.

CONCLUSION

Antibiotic therapy in the elderly requires a comprehensive approach, including strategies to improve appropriate antibiotic prescribing, limit their use for uncomplicated infections and ensure the attainment of an optimal PK/PD target. To this purpose, further studies involving the elderly are needed to better understand the PK of antibiotics. Moreover, it is necessary to assess the role therapeutic drug monitoring in guiding antibiotic therapy in elderly patients in order to evaluate its impact on clinical outcome.

Characteristics and outcomes in patients with atrial fibrillation receiving direct oral anticoagulants in off-label doses

Background

We evaluated adherence to dosing criteria for patients with atrial fibrillation (AF) taking dabigatran or rivaroxaban and the impact of off-label dosing on thromboembolic and bleeding risk.

Methods

We used data for a retrospective cohort from a large U.S. health plan for Medicare beneficiaries age > =65 years with AF who initiated dabigatran or rivaroxaban during 2010–2016. Stroke and major bleeding were quantified in patients who were eligible for low dose but received standard dose, and in patients who were eligible for standard dose but received low dose.

Results

We identified 8035 and 19,712 patients who initiated dabigatran or rivaroxaban, respectively. Overall, 1401 (17.4%) and 7820 (39.7%) patients who received dabigatran and rivaroxaban met criteria for low dose, respectively. Of those, 959 (68.5%) and 3904 (49.9%) received standard dose. In contrast, 1013 (15.3%) and 2551 (21.5%) of patients eligible for standard dose dabigatran and rivaroxaban received low dose. Mean follow-up for patients eligible for low and standard dose dabigatran and rivaroxaban were 13.9, 15.1, 10.1, and 12.3 months, respectively. In unadjusted analyses, patients eligible for low or standard dose dabigatran and rivaroxaban but receiving off-label dose, had no differences in the rates of ischemic stroke. Among patients who met criteria for standard dose direct oral anticoagulants (DOAC), use of low dose was associated with significantly higher risk of any major bleeding (Dabigatran: HR = 1.44; 95% CI 1.14–1.8, P = 0.002, Rivaroxaban HR 1.34, 95% CI 1.11–1.6, P = 0.002) and gastrointestinal bleeding (Dabigatran: HR = 1.48; 95% CI 1.08–2, P = 0.016). In patients who met criteria for low dose DOACs, there was lower risk of major bleeding (Dabigatran: HR = 0.59; 95% CI 0.43–0.8, P < 0.001), gastrointestinal (Rivaroxaban: HR 0.79; 95% CI 0.64–0.98, P = 0.03) and intracranial bleeding (Dabigatran: HR = 0.33; 95% CI 0.12–0.9, P = 0.001) with standard dosing. After propensity matching, use of off-label doses was not associated with stroke, major, gastrointestinal or intracranial bleeding for either dabigatran or rivaroxaban.

Conclusions

While a significant number of patients receive higher or lower dose of dabigatran and rivaroxaban than recommended, we found no evidence of significant impact on thromboembolic or hemorrhagic outcomes.

Clinical Implications of Estimating Glomerular Filtration Rate with Three Different Equations Among Older People. Preliminary Results of the Project "Screening for Chronic Kidney Disease among Older People across Europe (SCOPE)"

We aimed at investigating to what extent CKD may be staged interchangeably by three different eGFR equations in older people, and evaluating the source of discrepancies among equations in a population of 2257 patients older than 75 years enrolled in a multicenter observational study. eGFR was calculated by CKD-EPI, BIS and FAS equations. Statistical analysis was carried out by Bland–Altman analysis. κ statistic was used to quantify the agreement between equations in classifying CKD stages. The impact of selected variables on the difference among equations was graphically explored. The average difference between BIS and FAS was −0.24 (95% limits of agreement (95%LA = −4.64–4.14) mL/min/1.73 m². The difference between CKD-EPI and BIS and between CKD-EPI and FAS was 8.97 (95%LA = −2.90–20.84) and 8.72 (95%LA = −2.11–19.56) mL/min/1.73 m², respectively. As regards CKD stage classification, κ value was 0.47 for both CKD-EPI vs. FAS and CKD-EPI vs. BIS, while BIS and FAS had similar classificatory properties (κ = 0.90). Muscle mass was found related to the difference between CKD-EPI and BIS (R² = 0.11) or FAS (R² = 0.14), but not to the difference between BIS and FAS. In conclusion, CKD-EPI and BIS/FAS equations are not interchangeable to assess eGFR among older people. Muscle mass may represent a relevant source of discrepancy among eGFR equations.

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.

How to adjust drug doses in chronic kidney disease

Drugs excreted by the kidney require dose reduction in chronic kidney disease. This adjustment depends on the severity of the disease and what proportion of the drug is eliminated by the kidneys

The estimated glomerular filtration rate can generally be used to guide dose adjustment in patients with stable kidney function. However, the formula can be misleading in some patient subsets and other approaches are required

At extremes of body mass, the estimated glomerular filtration rate can under- or overestimate kidney function. It may need to be adjusted for body surface area, particularly for drugs with a narrow therapeutic range or requiring a minimum concentration to be effective. Close monitoring of drug effect and toxicity is also needed and can be supported by therapeutic drug monitoring

For short courses of drugs with a wide therapeutic index, dose adjustment may not be needed

Alternative methods for quantifying kidney function include the Cockcroft-Gault formula (estimates creatinine clearance) or direct measures of glomerular filtration rate using exogenous isotope compounds. These are not commonly required

Evaluation of renal function equations to predict amikacin clearance

Objective: To evaluate the predictive performance of eight renal function equations to describe amikacin elimination in a large standard population with a wide range of age. Methods: Retrospective study of adult hospitalized patients treated with amikacin and monitored in the clinical pharmacokinetics laboratory of a pharmacy service. Renal function was calculated as Cockcroft-Gault with total, adjusted and ideal body weight, MDRD-4, CKD-EPI, rLM, BIS1, and FAS. One compartment model with first-order elimination, including interindividual variability on clearance and volume of distribution and combined residual error model was selected as a base structural model. A pharmaco-statistical analysis was performed following a non-linear mixed effects modeling approach (NONMEM 7.3 software). Results: 198 patients (61 years [18-93]) and 566 measured amikacin plasma concentrations were included. All the estimated glomerular filtration rate and creatinine clearance equations evaluated described properly the data. The linear relationship between clearance and glomerular filtration rate based on rLM showed a statistically significant improvement in the fit of the data. rLM must be evaluated carefully in renal failure for amikacin dose adjustment. Conclusions: Revised Lund-Malmö (rLM) and CKD-EPI showed the superior predictive performance of amikacin drug elimination comparing to all the alternative metrics evaluated.

Choice of Renal Function Estimator Influences Adverse Outcomes with Dabigatran Etexilate in Patients with Atrial Fibrillation

Background  Clinical significance of dosing dabigatran with different estimates of renal function for treatment of atrial fibrillation (AF) is unknown. Renal function is routinely estimated by the chronic kidney disease epidemiology initiative equation (CKD-EPI) and used to guide dosing. The aim of this study was to investigate the risk of adverse outcomes for patients with AF when different estimators of renal function are used.

Material and Methods  AF patient data were extracted from national administrative databases. Renal function was estimated using Cockcroft–Gault, CKD-EPI, and CKD-EPI adjusted for body surface area (CKD-EPI-BSA). Outcomes of cerebrovascular accident (CVA), systemic embolism (SE), and hemorrhage were extracted.

Results  In total, 2,425 patients were identified, of which there were hospitalizations for 138 (5.7%) hemorrhagic events, 45 (1.9%) CVA/SE, and 33 (1.4%) unspecified CVA. The level of agreement between Cockcroft–Gault with CKD-EPI and CKD-EPI-BSA yielded a weighted kappa statistic of 0.47 and 0.71, respectively. CKD-EPI and CKD-EPI-BSA significantly overestimated renal function in elderly patients resulting in higher recommended doses compared with Cockcroft–Gault. The hazard ratio for a hemorrhagic event was 2.32 (95% confidence interval, 1.22–4.42; p  = 0.01) when a high dose was given compared with normal dose, based on Cockcroft–Gault.

Conclusion  Both CKD-EPI and CKD-EPI-BSA equations significantly overestimated renal function in the elderly population compared with the Cockcroft–Gault equation. This may lead to dose selection errors for dabigatran, particularly for those with severe impairment, increasing the risk of adverse outcome. Hence, CKD-EPI and CKD-EPI-BSA equations should not be substituted for the Cockcroft–Gault equation in the elderly for the purpose of renal dosage adjustments.

Loquat leaf polysaccharides improve glomerular injury in rats with anti-Thy 1 nephritis via peroxisome proliferator-activated receptor alpha pathway

Chronic glomerulonephritis frequently develops into renal failure that cannot be completely cured. Based on the success of anti-inflammatory Chinese herbs in treating chronic nephritis, our goal was to investigate the therapeutic effects and mechanism of action of loquat leaf polysaccharides (LLPS) on chronic anti-Thy-1 nephritis. A rat model of glomerulonephritis was used to study the effects of 8 weeks of enalapril or LLPS treatment. Twenty-four-hour rat urinary protein excretions were measured every week for 8 weeks. Then, all animals were sacrificed, renal-related biochemical parameters were analyzed, and histology and electron microscopy examinations of renal tissue samples were conducted. Renal cortex tissue was used to detect markers of renal fibrosis. RNA sequencing (RNA-seq) and in vitro experiments explored the signaling pathway involved in LLPS treatment effects. Compared with the disease control group, LLPS treatment significantly decreased the levels of serum creatinine and blood urea nitrogen, reduced urinary protein excretion, glomerular mesangial cell proliferation, and extracellular matrix hyperplasia, and attenuated the expression of proteins associated with podocyte injury and renal fibrosis. RNA-seq results showed that peroxisome proliferator-activated receptor (PPAR) is a potential signaling pathway involved in LLPS treatment of chronic glomerulonephritis. Increases in PPARα and plasminogen activator inhibitor-1 (PAI-1) caused by glomerulonephritis were inhibited by LLPS in vitro. Furthermore, when an agonist of PPARα (BMS-687453) was used to stimulate PPARα activity, LLPS treatment suppressed the expression of fibrosis factor PAI-1 partially via PPARα inhibition. These findings demonstrate that LLPS improved glomerular injury in rats with anti-Thy 1 nephritis via the PPARα pathway.

Multiparametric ultrasound in the evaluation of kidney disease in elderly

After the age of 30 years, GFR progressively declines at an average rate of 8 mL/min/1.73 m/decade. A problem of advanced age is that the evaluation of renal function on the basis of indicators valid in young adults, such as creatininemia, is unreliable. In fact, many patients with chronic renal failure may have serum creatinine levels within the normal range even if they have a significant reduction in renal function. Ultrasound has become a routine method of investigation in renal disease: kidney size and parenchymal echogenicity are considered markers of renal function, so US is useful in assessing the presence and degree of renal failure. CEUS is useful in the evaluation of kidney disease in the elderly: the increased hemodynamic resistance of renal microvessels reduces perfusion in the renal cortex, so fewer microbubbles enter the renal cortex. EcoColor and EcoDoppler are also useful in the evaluation of senile alterations: here, the distribution of color-signals, as compared to that in the young adult population, appears more attenuated, limited to intersegmental and interlobar districts. Among the ecoDoppler parameters, the resistance index can be considered a marker of renal damage progression, with attention needing to paid to possible concomitant confounding factors. Ultrasonography, color-Doppler and CEUS are a non-invasive and convenient modality for managing kidney disease; their integration with anamnestic, objective and laboratory data permits fast and reliable clinical, diagnostic, and therapeutic classification. It also allows early therapeutic intervention and, ultimately, improvements in patient management.

Medication decision-making for patients with renal insufficiency in inpatient and outpatient care at a US Veterans Affairs Medical Centre: a qualitative, cognitive task analysis

BACKGROUND

Many studies identify factors that contribute to renal prescribing errors, but few examine how healthcare professionals (HCPs) detect and recover from an error or potential patient safety concern. Knowledge of this information could inform advanced error detection systems and decision support tools that help prevent prescribing errors.

OBJECTIVE

To examine the cognitive strategies that HCPs used to recognise and manage medication-related problems for patients with renal insufficiency.

DESIGN

HCPs submitted documentation about medication-related incidents. We then conducted cognitive task analysis interviews. Qualitative data were analysed inductively.

SETTING

Inpatient and outpatient facilities at a major US Veterans Affairs Medical Centre.

PARTICIPANTS

Physicians, nurses and pharmacists who took action to prevent or resolve a renal-drug problem in patients with renal insufficiency.

OUTCOMES

Emergent themes from interviews, as related to recognition of renal-drug problems and decision-making processes.

RESULTS

We interviewed 20 HCPs. Results yielded a descriptive model of the decision-making process, comprised of three main stages: detect, gather information and act. These stages often followed a cyclical path due largely to the gradual decline of patients' renal function. Most HCPs relied on being vigilant to detect patients' renal-drug problems rather than relying on systems to detect unanticipated cues. At each stage, HCPs relied on different cognitive cues depending on medication type: for renally eliminated medications, HCPs focused on gathering renal dosing guidelines, while for nephrotoxic medications, HCPs investigated the need for particular medication therapy, and if warranted, safer alternatives.

CONCLUSIONS

Our model is useful for trainees so they can gain familiarity with managing renal-drug problems. Based on findings, improvements are warranted for three aspects of healthcare systems: (1) supporting the cyclical nature of renal-drug problem management via longitudinal tracking mechanisms, (2) providing tools to alleviate HCPs' heavy reliance on vigilance and (3) supporting HCPs' different decision-making needs for renally eliminated versus nephrotoxic medications.

The Role of Deprescribing in Older Adults with Chronic Kidney Disease

Older adults with chronic kidney disease (CKD) often experience polypharmacy, a recognized predictor of prescribing problems including inappropriately dosed medications, drug-drug and drug-disease interactions, morbidity and mortality. Polypharmacy is also associated with nonadherence, which leads to recurrent hospitalizations and poorer hemodialysis outcomes in CKD patients. Further complicating medication management in this vulnerable population are the physiologic changes that occur with both age and CKD. This guide for pharmacists and prescribers offers considerations in medication evaluation and management among older adults with CKD. Careful prescribing with the aid of tools such as the American Geriatrics Society Beers Criteria can support safe medication use and appropriate prescribing. Polypharmacy may be systematically addressed through 'deprescribing,' an evidence-based process that enables identification and elimination of unnecessary or inappropriate medications. Detailed guidance for deprescribing in older adults with CKD has not been published previously. We highlight three specific targets for medication optimization and deprescribing in older adults with CKD: (1) proton pump inhibitors, (2) oral hypoglycemic agents, including newer classes of agents, and (3) statins. These medication classes have been chosen as they represent three of the most commonly prescribed classes of medications in the United States. For each area, we review considerations for medication use in older adults with CKD and provide strategies to avoid, modify, or discontinue these medications when clinically indicated. By utilizing deprescribing techniques, pharmacists are well positioned to help decrease the medication burden in older adults with CKD, thereby potentially reducing the risk of morbidity and mortality associated with polypharmacy.