Creatinine Clearance Is Not Equal to Glomerular Filtration Rate and Cockcroft-Gault Equation Is Not Equal to CKD-EPI Collaboration Equation

Discrepancies among equations to estimate the glomerular filtration rate for drug dosing decision making in aged patients: a cross sectional study

BACKGROUND

Patients often require adjustments to drug doses due to impaired renal function. Glomerular filtration rate (GFR) estimation using various equations can result in discrepancies, potentially leading to different dose adjustment recommendations.

AIM

To determine the clinical significance of discrepancies observed between different equations used to estimate GFR for drug dose adjustments in a real-world group of patients over 65 years in primary care.

METHOD

The Cockcroft-Gault (CG), Modification of Diet in Renal Disease (MDRD), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), and Berlin Initiative Study 1 equations were applied to estimate GFR in a group of patients over 65 years old attending a primary care center. Results were compared using Bland-Altman plots, and limits of agreement (LoA) and overall bias were calculated. Regression analyses were conducted to identify the null difference GFR and the slope of differences for each pairwise comparison.

RESULTS

A total of 1886 patients were analyzed. Differences between patient-adjusted and body surface area (BSA)-normalized versions of the equations were not clinically relevant for dose adjustments, with LoAs below 20 mL/min. However, discrepancies among the original versions of several equations presented LoAs over 30 mL/min. Greater differences were found between CG and MDRD or CKD-EPI equations.

CONCLUSION

Clinically relevant differences in GFR estimation were observed among different equations, potentially impacting drug dose adjustments. However, discrepancies were not considered significant when comparing patient-adjusted and BSA-normalized versions of the equations, particularly for patients with BSA close to the average.

Prediction of worsening postoperative renal function in older candidates to elective cardiac surgery: Choosing the best eGFR formula may not be enough

BACKGROUND

Though renal impairment is highly prevalent in older patients and influence post-operative outcomes in cardiac surgery; its prognostic relevance is debated and not fully assessed by surgical risk scores.

OBJECTIVE

We investigated the predictive role of estimated glomerular filtration rate formulas for in-hospital worsening renal function (WRF) after cardiac surgery.

METHODS

We prospectively enrolled in single-center cohort study, patients aged ≥ 75 years candidate to elective cardiac surgery. Four creatinine-based equations were used to calculate estimated glomerular filtration rate (eGFR) formulas: Cockroft-Gault, Modification of Diet in Renal Disease, Chronic Kidney Disease Epidemiology, and Berlin Initiative Study 1 formulas. Each patient underwent geriatric and clinical evaluation before surgery with calculation of the Society of Thoracic Surgeons scores. In-hospital WRF was defined as a composite of an increase in SCr ≥0.5 mg/dl or the occurrence of grade III KDIGO acute kidney injury. The association between each eGFR equation, alone and in models including clinical variables, and WRF was analyzed using logistic regressions and ROC analysis.

RESULTS

WRF occurred in 69 patients (19.8%), and the predictors of WRF were previous acute myocardial infarction, hypertension, 4-mt gait speed performance, and preoperative eGFR, irrespective of the equation used. With all equations, inclusion of these additional variables in the logistic regression models improved the prediction of WRF (AUCs 0.798-0.810).

CONCLUSIONS

An accurate assessment of renal function and of physical performance should be incorporated into cardiac surgery risk scores to improve prediction of in-hospital WRF and, hence, risk stratification in older adults undergoing elective cardiac surgery.

Prescription of DOACs in Patients with Atrial Fibrillation at Different Stages of Renal Insufficiency

Atrial fibrillation (AF) and renal insufficiency often coexist and are increasingly prevalent with advancing age. Both the risk of thromboembolic events and bleeding propensity are higher in patients with AF and impaired renal function versus those with good renal health. Direct oral anticoagulants (DOACs) are being increasingly preferred over vitamin K antagonists (VKAs) in the treatment of patients with AF and impaired renal function as VKAs may accelerate progression of chronic kidney disease. DOACs, however, are eliminated by the kidneys to varying degrees, and their dosages must be adapted in accordance with renal function. Since creatinine clearance (CrCl) monitoring is recommended in patients with AF receiving DOAC therapy, CrCl must be routinely monitored in patients at the start and during the course of anticoagulation to avoid deviation from Summary of Product Characteristics dosage specifications. This review article provides an overview of current knowledge on the selection and dose of DOACs including apixaban, dabigatran, edoxaban and rivaroxaban in AF patients at different stages of renal insufficiency, with a special focus on elderly patients with comorbidities and receiving multiple medications. The groups discussed in this review include patients with varying levels of CrCl including hyperfiltration or CrCl > 90 ml/min, CrCl < 90-50 ml/min, CrCl < 50-30 ml/min, CrCl < 30-15 ml/min and end-stage renal disease or on dialysis.

New and old GFR equations: a European perspective

Glomerular filtration rate (GFR) is estimated in clinical practice from equations based on the serum concentration of endogenous biomarkers and demographic data. The 2009 creatinine-based Chronic Kidney Disease Epidemiology Collaboration equation (CKD-EPI2009) was recommended worldwide until 2021, when it was recalibrated to remove the African-American race factor. The CKD-EPI2009 and CKD-EPIcr2021 equations overestimate GFR of adults aged 18-30 years, with a strong overestimation in estimated GFR (eGFR) at age 18 years. CKD-EPICr2021 does not perform better than CKD-EPI2009 in US population, overestimating GFR in non-Black subjects, and underestimating it in Black subjects with the same magnitude. CKD-EPICr2021 performed worse than the CKD-EPI2009 in White Europeans, and provides no or limited performance gains in Black European and Black African populations. The European Kidney Function Consortium (EKFC) equation, which incorporates median normal value of serum creatinine in healthy population, overcomes the limitations of the CKD-EPI equations: it provides a continuity of eGFR at the transition between pediatric and adult care, and performs reasonably well in diverse populations, assuming dedicated scaling of serum creatinine (Q) values is used. The new EKFC equation based on cystatin C (EKFCCC) shares the same mathematical construction, namely, it incorporates the median cystatin C value in the general population, which is independent of sex and ethnicity. EKFCCC is therefore a sex-free and race-free equation, which performs better than the CKD-EPI equation based on cystatin C. Despite advances in the field of GFR estimation, no equation is perfectly accurate, and GFR measurement by exogenous tracer clearance is still required in specific populations and/or specific clinical situations.

Determination of creatinine in urine and blood serum human samples by CZE-UV using on-column internal standard injection

Creatinine is a well-stablished biomarker for kidney malfunctions and for normalization parameter of urinary quantitative information. Recently, metabolic studies have been discovering other functionalities for creatinine tests in human urine and blood serum. In this work we present an enhanced capillary electrophoresis (CE) based protocol for determination of creatinine. CE is a high-throughput separation technique that have been getting attention through the last decades and might be considered to be adopted as an analytical instrumentation for clinical purposes. In the proposed method, we performed a short injection program with on-column addition of internal standard. Additionally, the method allows a simultaneous screening of non-proteinogenic amino acids that could be considered for metabolomics purposes. We design a pilot study that successfully estimated the creatinine value in 100 urine samples with (2.85 ± 1.78) mg dL^-1 LOD; (8.24 ± 5.93) mg dL^-1 LOQ and 82.4% accuracy. Considering that serum creatinine is also included in the clinical laboratory routines for estimated Glomerular Filtration Rate dosage, the method was complementary applied to 10 blood serum samples, which resulted in a model with (0.4 ± 0.2) mg dL^-1 LOD; (2.0 ± 0.6) mg dL^-1 LOQ and 83.8% of accuracy. All results were in agreement with reference values. The proposed method promotes a great analytical frequency and reproducibility with enhanced specificity compared with the ongoing protocol by Jaffe's reaction, thereby proving to be useful as an alternative for creatinine exams that might help complete a diagnosis of a series of health-related issues.

Accuracy of the methods used to estimate glomerular filtration rate compared to 24-hour urinary creatinine clearance in patients with chronic spinal cord injury

OBJECTIVE

To compare the accuracy of glomerular filtration rate (GFR) estimation by 24-hour urinary creatinine clearance with GFR estimation by the Modification of Diet in Renal Disease (MDRD) equation, the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation, the Mayo Clinic Quadratic equation (MCQE), and the modified Cockcroft-Gault formula in patients with spinal cord injury (SCI).

DESIGN

Cross-sectional study.

PARTICIPANTS

Fifty-nine consecutive subjects, who were admitted to our hospital SCI rehabilitation and no additional acute medical disorders, were enrolled in this study. A 24-hour urine sample was collected for the determination of 24-hour urinary creatinine clearance, which was assumed as the standard technique for estimation of the GFR. The accuracy of several estimation formulas includes the 4-variable MDRD equation, the 6-variable MDRD equation, the Cockcroft and Gault equation, the CKD-EPI equation, and the MCQE.

RESULTS

GFRs calculated by the Cockcroft-Gault equation and 4-variable MDRD were significantly different from the 24-hour urinary creatinine clearance, whereas there were no significant differences in GFRs calculated by CKD-EPI (P = 1.000), Mayo Clinic Quadratic formula (P = 0.794), and 6-variable MDRD equations (P = 0.435) and 24-hour urinary creatinine clearance. Both the 6-variable MDRD equation and CKD-EPI were accurate within ±20 of the reference methods in 52.54% of the subjects.

CONCLUSIONS

Among the methods used for estimation of the GFR including the 4- and 6-variable MDRD, the CKD-EPI, the modified Cockcroft-Gault equation, and the MCQE, the 6-variable MDRD equation and the CKD-EPI demonstrated best performance to estimate the GFR. However, none of the formulas were sufficient to estimate the GFR in SCI patients accurately.

Time to Rethink the Current Paradigm for Assessing Kidney Function in Drug Development and Beyond

Chronic kidney disease (CKD) is an important health issue that affects ~ 9.1% of the world adult population. Serum creatinine is the most commonly used biomarker for assessing kidney function and is utilized in different equations for estimating creatinine clearance or glomerular filtration rate (GFR). The Cockcroft-Gault formula for adults and "original" Schwartz formula for children have been the most commonly used equations for estimating kidney function during the last 3-4 decades. Introduction of standardized serum creatinine bioanalytical methodology has reduced interlaboratory variability but is not intended to be used with Cockcroft-Gault or original Schwartz equations. More accurate equations (for instance, Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) for adults and bedside Schwartz or Chronic Kidney Disease in Children Schwartz equation for children) based on standardized serum creatinine values (and another biomarker-cystatin C) have been introduced and validated in recent years. Recently, the CKD-EPI equation refitted without a race variable was introduced. Clinical practice guidance in nephrology advocates a shift to these equations for managing health care of patients with CKD. The guidance also recommends use of albuminuria in addition to GFR for CKD diagnosis and management. Significant research with large data sets would be necessary to evaluate whether this paradigm would also be valuable in drug dose adjustments. This article attempts to highlight some important advancements in the field from a clinical pharmacology perspective and is a call to action to industry, regulators, and academia to rethink the current paradigm for assessing kidney function to enable dose recommendation in patients with CKD.

Ten-year Time-trend Analysis of Dyslipidemia Among Adults in Wuhan

OBJECTIVE

Dyslipidemia is associated with an increased risk of cardiovascular disease, the major cause of death in an aging population. This study aimed to estimate the prevalence of dyslipidemia for the past decade among adults in Wuhan, China.

METHODS

We performed a serial cross-sectional study that recruited 705 219 adults from the Health Management Center of Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology from 2010 to 2019. The diagnosis of dyslipidemia was based on the 2016 Chinese Guidelines for the Management of Dyslipidemia in Adults. Fixed effects and random effects models were applied to adjust the confounding variables (gender and age).

RESULTS

The overall prevalence of dyslipidemia was 33.1% (46.2% in men and 14.7% in women) in 2019. The prevalence of dyslipidemia was significantly increased over 10 years [from 28.6% (95% CI: 28.2%-29.1%) in 2010 to 32.8 % (95% CI:32.6%-33.1%) in 2019;. P-0.001], especially for hypo-high-density lipoprotein cholesterolemia [from 18.4% (95% CI: 18.0%-18.8%) in 2010 to 24.5% (95% CI: 24.3%-24.7%) in 2019; P-0.001]. In 2019, the prevalence of dyslipidemia was higher in participants with comorbidities, including overweight/obesity, hypertension, diabetes, hyperuricemia, or chronic kidney disease, and dyslipidemia was the most significant among participants aged 30-39 years.

CONCLUSION

This study demonstrated that dyslipidemia is on the rise in men, and more emphasis should be provided for the screening of dyslipidemia in young males for the primary prevention of cardiovascular and renal diseases.

Implementing evidence-based anticoagulant prescribing: User-centered design findings and recommendations

Background

Direct oral anticoagulants (DOACs) are widely used medications with an unacceptably high rate of prescription errors and are a leading cause of adverse drug events. Clinical decision support, including medication alerts, can be an effective implementation strategy to reduce prescription errors, but quality is often inconsistent. User‐centered design (UCD) approaches can improve the effectiveness of alerts.

Objectives

To design effective DOAC prescription alerts through UCD and develop a set of generalizable design recommendations

Methods

This study used an iterative UCD process with practicing clinicians. In three rapid iterative design and assessment stages, prototype alert designs were created and refined using a test electronic health record (EHR) environment and simulated patients. We identified key emergent themes across all user observations and interviews. The themes and final designs were used to derive a set of design guidelines.

Results

Our UCD sample comprised 13 prescribers, including advanced practice providers, physicians in training, primary care physicians, and cardiologists. The resulting alert designs embody our design recommendations, which include establishing intended indication, clarifying dosing by renal function, tailoring alert language in drug interactions, facilitating trust in alerts, and minimizing interaction overhead.

Conclusions

Through a robust UCD process, we have identified key recommendations for implementing medication alerts aimed at improving evidence‐based DOAC prescribing. These recommendations may be applicable to the implementation of DOAC alerts in any EHR systems.

Gender-specific differences in hemodialysis patients: a multicenter longitudinal study from Serbia

PURPOSE

The study was undertaken with the aim to determine gender-specific differences in incident hemodialysis (HD) patient and their changes over time.

METHODS

The retrospective longitudinal closed cohort study involved 441 incident patients starting HD in 2014 and followed for 1-59 (median 43, IQR 40) months. Demographic, clinical data, treatment characteristics, laboratory findings and outcome were abstracted from the patients' medical records.

RESULTS

The relative number of males on HD was about twice that of females throughout the five years investigated. At the beginning of the study, no significant differences were found in the main demographic and clinical characteristics except that diabetes was more often the underlying disease in men than in women. Systolic blood pressure decreased over time significantly more in females than in males. Throughout the study spKt/V was significantly higher in females than in males, but it increased in patients of both genders. There were no gender differences for comorbidities, vascular access and the majority of laboratory findings except for higher serum levels of creatinine and CRP in men than in women. Relatively more females were treated with erythropoiesis stimulating agents and phosphate binders than males. Age and malignancy were selected as significant predictors of mortality for both genders, and, in addition, polycystic kidney disease, serum level of albumin and CRP for men, but spKt/V for women.

CONCLUSION

Some significant gender differences were observed throughout, while others appeared during the study but none of them were due to gender inequalities in the applied treatment.

Predictors of 1-year outcome in very old patients managed in a Heart Failure Unit after an acute decompensation

PURPOSE

Consensus exits about the clinical benefits of an early referral to multidisciplinary Heart Failure Unit-HFU for old frail patients with HF. Nevertheless, few data are present regarding the prognosis and the predictors of outcome in oldest-old patients managed in this clinical setting. The aim of present study is to identify predictors of 1-year all-cause mortality in very old patients enrolled in our multidisciplinary HFU after an episode of acute decompensated HF.

METHODS

This study is a retro-prospective, single-center cohort analysis of patients managed in our multidisciplinary HFU. Inclusion criterion was diagnosis of HF according to ESC guidelines and age ≥ 85 years, while no exclusion criteria were pre-defined. Baseline clinical and comprehensive geriatric evaluations were recorded during the first visit and follow-up visits were repeated according to our standardized timetable protocol. Primary end-point was 1-year all-cause mortality.

RESULTS

We enrolled 75 patients aged 89.2 ± 2.8 years; 39 (52.0%) were females. During 1-year follow-up, seventeen patients (22.7%) died. Residual congestion with higher level (> 4) of EVEREST score (HR 1.24: 95% CI 1.04-1.47) and living alone (HR 3.34: 95% CI 1.16-9.64) resulted the two independent predictors of 1-year all-cause mortality at the multivariate Cox regression model. Finally, patients living alone and with an EVEREST score > 4 experienced a worse prognosis as clearly described by a steeper descendent Kaplan-Meier curve.

CONCLUSION

In a very old population of patients after an acute decompensated HF, residual congestion and social isolation as living alone identify those with high risk of 1-year death.

Estimating urine volume from the urine creatinine concentration

Spot determinations of the urine creatinine concentration are widely used as a substitute for 24-hour urine collections. Expressed as the amount excreted per gram of creatinine, urine concentrations in a single-voided sample are often used to estimate 24-hour excretion rates of protein, sodium, potassium, calcium, magnesium, urea, and uric acid. These estimates are predicated on the assumption that daily creatinine excretion equals 1 gm (and that a urine creatinine concentration of 100 mg/dl reflects a 1 Liter 24-hour urine volume). Such estimates are invalid if the serum creatinine concentration is rising or falling. In addition, because creatinine excretion is determined by muscle mass, the assumption that 24-hour urine creatinine excretion equals 1 gm yields a misleading estimate at the extremes of age and body size. In this review we evaluate seven equations for the accuracy of their estimates of urine volume based on urine creatinine concentrations in actual and idealized patients. None of the equations work well in patients who are morbidly obese or in patients with markedly decreased muscle mass. In other patients, estimates based on a reformulation of the Cockroft-Gault equation are reasonably accurate. A recent study based on this relationship found a high strength of correlation between estimated and measured urine output with chronic kidney disease (CKD) studied in the African American Study of Kidney Disease (AASK) trial and for the patients studied in the CKD Optimal Management with Binders and NictomidE (COMBINE) trial. However, the equation systematically underestimated urine output in the AASK trial. Hence, an intercept was added to account for the bias in estimated output. A more rigorous equation, derived from an ambulatory Swiss population, that includes body mass index and models the non-linear accelerated decline in creatinine excretion with age, could potentially be more accurate in overweight and elderly patients. In addition to extremes of body weight and muscle mass, decreased dietary intake or reduced hepatic synthesis of creatine, a precursor of creatinine, or ingestion of creatine supplements will also result in inaccurate estimates. These limitations must be appreciated to rationally use predictive equations to estimate urine volume. If the baseline urine creatinine concentration is determined in a sample of known volume, subsequent urine creatinine concentrations will reveal actual urine output as well as the change in urine output. Given the constraints of the various estimating equations, a single baseline timed collection may be more useful strategy for monitoring urine volume than entering anthropomorphic data into a calculator.

Measurement of glomerular filtration rate reveals that subcapsular injection of shear-thinning hyaluronic acid hydrogels does not impair kidney function in mice

The continued development of minimally invasive therapeutic implants, such as injectable hydrogels, necessitates the concurrent advancement of methods to best assess their biocompatibility via functional outcomes in vivo. Biomaterial implants have been studied to treat kidney disease; however, assessment of biocompatibility has been limited to biomarker and histological assessments. Techniques now exist to measure kidney function serially in vivo in murine studies via transcutaneous measurements of glomerular filtration rate (tGFR). In this study, adult male and female wild-type BalbC mice underwent right unilateral nephrectomy. The remaining solitary left kidney was allowed 4 weeks to recover via compensatory hypertrophy, after which subcapsular injection of either saline or shear-thinning hyaluronic acid hydrogel was performed. Serial tGFR measurements before and after treatment were used to assess the effect of hydrogel injection on kidney filtration. Urine and serum biomarkers of kidney function, and kidney histology were also quantified. Hydrogel injection did not affect kidney function, as assessed by tGFR. Results were in agreement with standard metrics of serum and urine biomarkers of injury as well as histological assessment of inflammation. The model developed provides a direct functional assessment of implant compatibility for the treatment of kidney disease and impact on kidney function.

Non-valvular Atrial Fibrillation in CKD: Role of Vitamin K Antagonists and Direct Oral Anticoagulants. A Narrative Review

Atrial fibrillation (AF) is the most common arrhythmia in chronic kidney disease (CKD), with a close bidirectional relationship between the two entities. The presence of CKD in AF increases the risk of thromboembolic events, mortality and bleeding. Vitamin K antagonists (VKA) have been the mainstay of treatment for the prevention of thromboembolic events in AF until recently, with confirmed benefits in AF patients with stage 3 CKD. However, the risk-benefit profile of VKA in patients with AF and stages 4-5 CKD is controversial due to the lack of evidence from randomized controlled trials. Treatment with VKA in CKD patients has been associated with conditions such as poorer anticoagulation quality, increased risk of bleeding, faster progression of vascular/valvular calcification and higher risk of calciphylaxis. Direct oral anticoagulants (DOACs) have shown equal or greater efficacy in stroke/systemic embolism prevention, and a better safety profile than VKA in post-hoc analysis of the pivotal randomized controlled trials in patients with non-valvular AF and stage 3 CKD, yet evidence of its risk-benefit profile in more advanced stages of CKD is scarce. Observational studies associate DOACs with a good safety/effectiveness profile compared to VKA in non-dialysis CKD patients. Further, DOACs have been associated with a lower risk of acute kidney injury and CKD development/progression than VKA. This narrative review summarizes the evidence of the efficacy and safety of warfarin and DOACs in patients with AF at different CKD stages, as well as their effects on renal function, vascular/valvular calcification and bone health.

Design and methodology of the chronic kidney disease as a dysmetabolic determinant of disability among older people (CKD-3D) study: a multicenter cohort observational study

Background

Chronic kidney disease (CKD) is a common condition in older people and represents a global health issue since it increases the risk of associated comorbidities and all-cause mortality. Furthermore, older people with reduced renal function might be at higher risk for developing functional limitation and disability. Moreover, the current creatinine-based measures of renal function are influenced by several factors in older population. The aims of the CKD-3D project are to perform an observational study to expand the knowledge about CKD-disability relationship and to investigate the use of novel biomarkers of kidney function.

Methods

An observational, multicenter, prospective cohort study will be conducted in 75 + old patients consecutively admitted to acute care wards of geriatric medicine at participating hospitals. The study planned to enroll 440 patients undergoing clinical and laboratory evaluations at baseline and after 12 months. Face-to-face follow-up at 6 months and telephone follow-up at 3 and 9 months will be carried out. Comprehensive Geriatric Assessment (CGA) and the measurement of Cystatin C, Beta-Trace Protein and Beta2-Microglobulin levels will be included.

Discussion

This study will provide useful information to prevent CKD-related disability by collecting real-life data over 1-year period. The combined approach of CGA and the investigation of innovative existing biomarkers will make it possible to develop new recommendations and guidelines for a patient-centered approach. It is believed that such a study may lead to an improvement of knowledge on CKD in elderly patients and may also have implications in daily clinical practice and in decision-making process.

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.

Thromboembolic and Hemorrhagic Outcomes in the Direct Oral Anticoagulant Trials Across the Spectrum of Kidney Function

Chronic kidney disease is a common comorbidity among patients taking direct-acting oral anticoagulants (DOACs). Herein, we evaluate the influence of kidney function on stroke or systemic embolism (SEE), hemorrhage, and composite end points (stroke/SEE/hemorrhage/death and stroke/SEE/death) among patients on DOACs and warfarin. Baseline kidney function was categorized as glomerular filtration rate (GFR) ≥ 60 (reference), 45-59, and < 45mL/min/1.73 m² for participants in the Randomized Evaluation of Long-Term Anticoagulant Therapy (RE-LY) (n = 18,049), Apixaban for Reduction in Stroke and Other Thromboembolic Events (ARISTOTLE) (n = 18,187), and The Effective Anticoagulation with Factor Xa Next Generation in AF (ENGAGE AF) (n = 20,798) trials. Incidence of events was compared across GFR categories. Hazard ratios for events were estimated using Cox regression using intention-to-treat analysis adjusting for known predictors. A large proportion of participants had GFR < 60 (25-29% had 45 ≤ GFR < 60 and 9.5-12.6% with GFR < 45). Compared with patients with GFR ≥ 60, warfarin users across the trials with GFR ≥ 45-59 and GFR < 45 had a higher incidence of hemorrhage (P values < 0.0001) and warfarin users in the ARISTOTLE and ENGAGE trials had higher incidence of stroke/SEE (P values ≤ 0.05). Compared with patients with GFR ≥ 60, dabigatran users with GFR ≥ 45-59 and GFR < 45 had a higher incidence of stroke/SEE (P ≤ 0.02), hemorrhage (P < 0.001), and both composite end points (P < 0.0001). Compared with patients with GFR ≥ 60, apixaban and edoxaban users with GFR ≥ 45-59 and GFR < 45 had a higher incidence of hemorrhage (P values ≤ 0.05) and composite end points (P values ≤ 0.05). After adjustment, compared with patients with GFR ≥ 60, warfarin users with GFR < 60 in the ARISTOTLE and RE-LY trials had a higher risk of hemorrhage (P < 0.05), as did dabigatran (P < 0.001) and edoxaban (P ≤ 0.005) users, while apixaban users did not exhibit an increased risk (P = 0.08 GFR ≥ 45-59; P = 0.71 GFR < 45). Kidney function significantly influences the safety and efficacy of oral anticoagulants.

Direct Measurement of Creatinine Clearance over a Short Interval in Intensive Care Settings

Background

The definition of acute kidney injury (AKI), based on serum creatinine and urine output, bears significant limitations in intensive care units (ICUs). Serum creatinine has significant lag-time as it needs to be accumulated and stabilized at a new level whereas urine output is affected by diuresis, antidiuresis, and antinatriuresis. Direct measurement of creatinine clearance (CrCl_direct = urine creatinine × urine flow rate/serum creatinine) over a short interval (3-6 hours) was explored to identify patients with AKI.

Materials and methods

We reanalyzed a previous published dataset. We included 11 patients who had serial daily urine collections over 0 to 3 days of stay in ICU and baseline (day -1) serum creatinine levels.

Result

The ratio of CrCl_direct on day 0 to baseline creatinine clearance predicted the progression of AKI over the subsequent 1 to 3 days of ICU stay [area under receiver operating characteristic curve = 0.933 and 95% confidence interval (CI) = 0.780-1.000].

Discussion

CrCl_direct over a short interval may be an alternative marker of kidney function. Future studies may explore its use to identify patients with AKI who may benefit from early renal replacement therapy.

How to cite this article

Law LSC, Lo EAG, Yeoh SF. Direct Measurement of Creatinine Clearance over a Short Interval in Intensive Care Settings. Indian J Crit Care Med 2021;25(7):800-802.

Predictive ability of creatinine clearance versus estimated glomerular filtration rate for outcomes in patients with non-valvular atrial fibrillation: Subanalysis of the J-RHYTHM Registry

BACKGROUND

Renal impairment is a risk factor for various adverse events, especially for death. In general, creatinine clearance (CrCl) is used for dose-adjustments of many drugs including oral anticoagulants, and estimated glomerular filtration rate (eGFR) is adopted for the diagnosis of chronic kidney disease. Predictive ability of CrCl versus eGFR for outcomes in patients with non-valvular atrial fibrillation (NVAF) remains controversial; therefore, this was compared using data from the J-RHYTHM Registry.

METHODS

Out of 7406 outpatients with NVAF from 158 institutions, 6004 (age, 69.7 ± 9.9 years; men, 71.2%) having data of CrCl (mL/min, by the Cockcroft-Gault formula), eGFR (mL/min/1.73 m2, by the equations of the Japanese Society of Nephrology), and body surface area (BSA) were analyzed. C-statistics (area under the receiver-operating characteristic curve) of CrCl and eGFR for events were compared by DeLong's test.

RESULTS

Thromboembolism, major hemorrhage, and all-cause death occurred in 107 (1.8%), 117 (1.9%), and 154 (2.6%) patients during the 2-year follow-up period. C-statistics of CrCl for each event were 0.609 (95% confidence interval, 0.559-0.658), 0.599 (0.548-0.657), and 0.746 (0.706-0.786); and those of eGFR were 0.542 (0.487-0.597), 0.573 (0.519-0.626), and 0.677 (0.631-0.723), respectively. C-statistics of CrCl for thromboembolism and all-cause death were significantly higher than those of eGFR (P < 0.001 for both). These results were consistent when BSA-unadjusted eGFR was used instead of eGFR (P = 0.002 for thromboembolism and P < 0.001 for all-cause death).

CONCLUSIONS

CrCl was superior to eGFR in the prediction of adverse outcomes, i.e., thromboembolism and all-cause death in Japanese patients with NVAF.

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.

Cystatin C: A Primer for Pharmacists

Pharmacists are at the forefront of dosing and monitoring medications eliminated by or toxic to the kidney. To evaluate the effectiveness and safety of these medications, accurate measurement of kidney function is paramount. The mainstay of kidney assessment for drug dosing and monitoring is serum creatinine (SCr)-based estimation equations. Yet, SCr has known limitations including its insensitivity to underlying changes in kidney function and the numerous non-kidney factors that are incompletely accounted for in equations to estimate glomerular filtration rate (eGFR). Serum cystatin C (cysC) is a biomarker that can serve as an adjunct or alternative to SCr to evaluate kidney function for drug dosing. Pharmacists must be educated about the strengths and limitations of cysC prior to applying it to medication management. Not all patient populations have been studied and some evaluations demonstrated large variations in the relationship between cysC and GFR. Use of eGFR equations incorporating cysC should be reserved for drug management in scenarios with demonstrated outcomes, including to improve pharmacodynamic target attainment for antibiotics or reduce drug toxicity. This article provides an overview of cysC, discusses evidence around its use in medication dosing and in special populations, and describes practical considerations for application and implementation.

GFR Measurement and Chemotherapy Dosing in Patients with Kidney Disease and Cancer

Chemotherapeutic agents require precise dosing to ensure optimal efficacy and minimize complications. For those agents that are removed from the body by the kidney, accurate knowledge of GFR is critical. In addition, GFR needs to be determined rapidly, easily, and, if possible, with little additional cost. The ability to easily measure GFR also allows for rapid detection of nephrotoxicity. Current methodologies include direct clearance measurement of an indicator substance or estimation of creatinine clearance or GFR through regression equations that use a serum marker, such as creatinine or cystatin C. These methodologies all have shortfalls and limitations, some of which are specific to the patient with cancer. Newer methodologies that directly measure GFR are in clinical trials and offer the ability to rapidly and noninvasively provide accurate estimates of drug clearance as well as detection of nephrotoxicity. These methods offer the opportunity to refine drug dosing and improve outcomes.

The chaos of hypertension guidelines for chronic kidney disease patients

Three major guidelines deal with blood pressure thresholds and targets for antihypertensive drug therapy in chronic kidney disease (CKD) patients: the 2012 Kidney Disease: Improving Global Outcomes Clinical Practice Guideline for the Management of Blood Pressure in Chronic Kidney Disease; the 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults; and the 2018 ESC/ESH Guidelines for the Management of Arterial Hypertension. However, a careful reading of the three guidelines leaves the practicing physician confused about the definition of CKD, how hypertension and secondary hypertension should be diagnosed in CKD patients and what the blood pressure thresholds, targets and compelling indications of antihypertensive drug therapy should be for this population. Current guidelines refer to different CKD populations and propose different definitions of hypertension, different thresholds to initiate antihypertensive therapy in CKD patients and different BP targets compelling antihypertensive drug use. The different bodies producing guidelines should work together towards a unified definition of CKD, a unified concept of hypertension and unified BP thresholds and targets for hypertensive drug therapy for CKD patients. Otherwise they risk promoting confusion and therapeutic nihilism among physicians and patients.

Use of rivaroxaban in patients attending a hematology unit in clinical practice

Aim: To determine drug persistence and rates of events among patients treated with rivaroxaban in a hematology unit. Methods: Retrospective study of patients that started treatment with rivaroxaban, in the hematology unit of a tertiary hospital. Results: A total of 161 patients were included, of whom 83.9% had atrial fibrillation and 11.2% venous thromboembolism, and 76.4% of patients were taking rivaroxaban 20 mg, 22.4% 15 mg and 1.2% 10 mg. After a follow-up of 1.8 ± 1.1 years, only four patients (2.5%) discontinued treatment. Rates of thromboembolic events, major bleeding/clinically relevant nonmajor bleeding and intracranial hemorrhage were 1.1, 2.8, 0.3 events per 100 patient-years, respectively. Conclusion: In patients attended in a hematology unit, medication persistence was high, and the incidence of outcomes low.

Evaluation of prophylactic dosages of Enoxaparin in non-surgical elderly patients with renal impairment

Background

Thromboprophylaxis dosing strategies using enoxaparin in elderly patients with renal disease are limited, while dose adjustments or monitoring of anti-Xa levels are recommended. We sought to evaluate the efficacy and safety of enoxaparin 20 mg versus 30 mg subcutaneously daily by comparing anti-Xa levels, thrombosis and bleeding.

Methods

We conducted a prospective, single-blinded, single-center randomized clinical trial including non-surgical patients, 70 years of age or older, with renal disease requiring thromboprophylaxis. Patients were randomized to receive either 20 mg or 30 mg of enoxaparin. The primary endpoint was peak anti-Xa levels on day 3. Secondary endpoints included trough anti-Xa levels on day 3, achievement of within range prophylactic target peak anti-Xa levels and the occurrence of hemorrhage, thrombosis, thrombocytopenia or hyperkalemia during hospitalization.

Results

Thirty-two patients were recruited and sixteen patients were randomized to each arm. Mean peak anti-Xa level was significantly higher in 30 mg arm (n = 13) compared to the 20 mg arm (n = 11) 0.26 ± 0.11, 95%CI (0.18–0.34), versus 0.14 ± 0.09, 95CI (0.08–0.19) UI/ml, respectively; p = 0.004. Mean trough anti-Xa level was higher in 30 mg arm (n = 10) compared to the 20 mg arm (n = 16), 0.06 ± 0.03, 95CI (0.04–0.08) versus 0.03 ± 0.03, 95CI (0.01–0.05) UI/ml, respectively; p = 0.044. Bleeding events reported in the 30 mg arm were one retroperitoneal bleed requiring multiple transfusions, and in the 20 mg arm one hematuria. No thrombotic events were reported.

Conclusion

Peak anti-Xa levels provided by enoxaparin 20 mg were lower than the desired range for thromboprophylaxis in comparison to enoxaparin 30 mg.

Trial registration

The trial was retrospectively registered on ClinicalTrials.gov identifier: NCT03158792. Registered: May 18, 2017.

Clarifying the concept of chronic kidney disease for non-nephrologists

Chronic kidney disease (CKD) expands the prior concept of chronic renal insufficiency by including patients with relatively preserved renal function, as assessed by the estimated glomerular filtration rate (eGFR), as even these early CKD stages are associated with an increased risk for all-cause death and cardiovascular death, CKD progression and acute kidney injury. A decreased eGFR (<60 mL/min/1.73 m²) is by itself diagnostic of CKD when persisting for >3 months. However, when eGFR is ≥60 mL/min/1.73 m², an additional criterion is required to diagnose CKD. In a recent clinical trial published in The New England Journal of Medicine, all 6190 participants were reported to have CKD: 47% had Stages 1 and 2 CKD and 53% had Stage 3 CKD. This illustrates a widespread misunderstanding of the concept of CKD. Moreover, CKD categories in this study were assigned based on the estimated creatinine clearance. Since both estimated creatinine clearance and creatinine clearance overestimate eGFR, this illustrates another frequent misunderstanding: equating GFR with creatinine clearance. In this commentary, we clarify the concept of CKD and of CKD categories for non-nephrologists. Assigning a diagnosis of CKD to a patient with normal renal function and absence of other evidence of CKD may have negative consequences for the individual (e.g. insurance and others) as well as for the medical community at large by creating confusion about the concept.

The efficacy and safety of direct oral anticoagulants in patients with chronic renal insufficiency: A review of the literature

Direct oral anticoagulants (DOACs) have been shown to be superior to vitamin K antagonists (VKAs) in regards to safety and efficacy in numerous clinical trials and are now the preferred oral anticoagulant by multiple professional societies. However, patients with significant levels of organ dysfunction were excluded from all major clinical trials, leaving the clinical benefit in these subsets uncertain. Patients with chronic kidney disease (CKD) specifically often require anticoagulation for acute or long-term indications such as venous thromboembolism, atrial fibrillation, or mechanical heart valves. The efficacy and safety of anticoagulation in patients with renal failure is less certain, however, particularly with DOACs which have altered pharmacokinetics in patients with renal failure and limited observational data on their use in this population. In this review, we compile the most up to date data on the DOAC use in patients with CKD. DOAC use in patients with ESRD and advanced CKD is increasing despite the presence of a clear benefit, and with the potential for increased risk of bleeding compared to warfarin. Apixaban has the greatest amount of outcomes research supporting its use over warfarin in this patient population; however, further research on DOAC safety and efficacy in those with advanced CKD is still needed.

The quest for equilibrium: exploring the thin red line between bleeding and ischaemic risks in the management of acute coronary syndromes in chronic kidney disease patients

Coronary artery disease and acute coronary syndrome (ACS) are both common in patients with chronic kidney disease (CKD). CKD patients have higher risks of bleeding and thrombosis. However, they remain under-represented in major randomized clinical trials (RCTs), and there is no medical evidence-based foundation on which to issue specific recommendations about the management of ACS in CKD. CKD patients with ACS frequently are diagnosed later, receive fewer acute interventions and are at increased risk of over-dosage of medications and under-prescription/under-performance of interventional treatments than CKD patients without ACS. The lack of RCTs should not discourage reliance on clinical common sense, while clearer decisional algorithms with better outcomes are a priority for urgent development. Future guidelines should further refine the assessment of CKD with ACS while placing much greater emphasis on the correct dosing of medications based on contemporaneous renal function. Until a strategy is designed with specific measures translated into the actual decrease of bleeding risk, providers will be forced to balance the equilibrium on a thin red line that is not clearly established.

Non-Vitamin K-Dependent Oral Anticoagulants for Nonvalvular Atrial Fibrillation in Patients With CKD: Pragmatic Considerations for the Clinician

Management of atrial fibrillation (AF) in patients with advanced chronic kidney disease (CKD) poses a complex conundrum because of higher risks for both thromboembolic and bleeding complications compared to the general population. This makes it particularly important for clinicians to carefully weigh the risks versus benefits of anticoagulation therapy to determine the individualized net clinical benefit for every patient. During the past few years, 4 non-vitamin K-dependent oral anticoagulant (NOAC) agents have supplemented warfarin in the therapeutic armamentarium for the prevention of systemic thromboembolism in nonvalvular AF. However, the use of NOACs in CKD specifically mandates a nuanced understanding due to their varying dependence on renal clearance, with resultant safety implications related to either underdosing (thromboembolism) or excessive drug exposure (bleeding). This pragmatic review highlights unique considerations pertaining to accurate estimation and temporal monitoring of kidney function in the context of NOAC use with specific clinical deliberations and variables when determining whether an NOAC is appropriate for a patient with CKD. The dependence of NOACs on renal clearance and several troubling safety signals in the published literature suggest that it is vital for nephrologists to be active members of a multidisciplinary team caring for these high-risk patients with CKD and AF.

DOAC use in patients with chronic kidney disease

Direct oral anticoagulants (DOACs) are increasingly prescribed substances in patients with indication for effective anticoagulation. Patients with chronic kidney disease (CKD) have a high burden of cardiovascular risk and are more likely to develop atrial fibrillation (AF) than patients without CKD. Patients with mild to moderate CKD benefit from DOACs, especially when having intolerance to vitamin K-antagonists (VKA). DOACs may in some cases be considered in patients with rare renal disease and hypercoagulabilic state. DOACs are to a large extent eliminated by renal excretion. Since prospective randomised data in CKD patients are sparse, the decision for anticoagulative therapy is challenging especially in patients with severe renal impairment. The direct factor Xa-inhibitors are approved for use even in patients with an estimated glomerular filtration rate (eGFR) between 15 and 30 ml/min. Careful monitoring of renal function on a regular basis is essential before initiation and after start of DOAC, especially for patients at risk for acute renal failure (elderly, diabetics, patients with preexisting kidney disease). None of the DOACs is approved in CKD patients with end-stage-renal-disease (ESRD) with or without dialysis. DOACs are not recommended for kidney transplant patients under immunosuppression with calcineurin inhibitors. In these patients conventional therapy with VKA is the only option, which has to be monitored closely since it has potential adverse effects.

Translational science in chronic kidney disease

The KDIGO definition of chronic kidney disease (CKD) allowed a more detailed characterization of CKD causes, epidemiology and consequences. The picture that has emerged is worrisome from the point of view of translation. CKD was among the fastest growing causes of death in the past 20 years in age-adjusted terms. The gap between recent advances and the growing worldwide mortality appears to result from sequential roadblocks that limit the flow from basic research to clinical development (translational research type 1, T1), from clinical development to clinical practice (translational research T2) and result in deficient widespread worldwide implementation of already available medical advances (translational research T3). We now review recent advances and novel concepts that have the potential to change the practice of nephrology in order to improve the outcomes of the maximal number of individuals in the shortest possible interval. These include: (i) updating the CKD concept, shifting the emphasis to the identification, risk stratification and care of early CKD and redefining the concept of aging-associated 'physiological' decline of renal function; (ii) advances in the characterization of aetiological factors, including challenging the concept of hypertensive nephropathy, the better definition of the genetic contribution to CKD progression, assessing the role of the liquid biopsy in aetiological diagnosis and characterizing the role of drugs that may be applied to the earliest stages of injury, such as SGLT2 inhibitors in diabetic kidney disease (DKD); (iii) embracing the complexity of CKD as a network disease and (iv) exploring ways to optimize implementation of existing knowledge.

Direct oral anticoagulants in patients with chronic kidney disease: patient selection and special considerations

Many patients with chronic kidney disease (CKD) receive anticoagulation or antiplatelet therapy due to atrial fibrillation, coronary artery disease, thromboembolic disease, or peripheral artery disease. The treatment usually includes vitamin K antagonists (VKAs) and/or platelet aggregation inhibitors. The direct oral anticoagulants (DOAC) inhibiting factor Xa or thrombin represent an alternative for VKAs. In patients with acute and chronic kidney disease, caution is warranted, as DOACs can accumulate as they are partly eliminated by the kidneys. Thus, they can potentially increase the bleeding risk in patients with CKD. In patients with an estimated glomerular filtration rate (eGFR) above 60 mL/min, DOACs can be used safely with greater efficacy and safety as compared to VKAs. In patients with CKD 3, DOACs are as effective as VKAs with a lower bleeding rate. The more the renal function declines, the lower is the advantage of DOACs over VKAs. Thus, use of DOACs should be avoided in patients with an eGFR below 30 mL/min, particularly, the compounds with a high renal elimination. Available data suggest that DOACs can also be used safely in older patients. In this review, use of DOACs in comparison with VKAs, heparins, and heparinoids, together with special considerations in patients with impaired renal function will be discussed.

Lesinurad: what the nephrologist should know

Lesinurad is an oral inhibitor of the monocarboxylic/urate transporter URAT1 encoded by the SLC22A12 gene. Market authorization was granted in February 2016 in Europe and December 2015 in the USA. As a potentially nephrotoxic uricosuric drug acting on the kidney, nephrologists should become familiar with its indications and safety profile. The approved indication is treatment of gout in combination with a xanthine oxidase (XO) inhibitor in adult patients who have not achieved target serum uric acid levels with an XO inhibitor alone. It is not indicated for asymptomatic hyperuricaemia or for patients with estimated creatinine clearance <45 mL/min. The only authorized daily dose is 200 mg and cannot be exceeded because of the nephrotoxicity risk. Nephrotoxicity is thought to be related to uricosuria. At the 200 mg/day dose, serum creatinine more than doubled in 1.8% of lesinurad patients (versus 0% in placebo) and in 11% of these it was not reversible. In addition, it is subject to a risk management plan given the potential association with cardiovascular events. In randomized clinical trials, the association of lesinurad with either allopurinol or febuxostat achieved a greater reduction in serum uric acid (∼1 mg/dL lower) than the XO inhibitors alone, and this allowed the serum uric acid target to be met in a higher proportion of patients, which was the primary endpoint. However, no clinical differences were observed in gout flares or tophi, although these were not the primary endpoints.