A comparison of bedside renal function estimates and measured glomerular filtration rate (Tc99mDTPA clearance) in cancer patients

A novel nomogram to predict the reliability of estimated glomerular filtration rate formulae in oncology patients

BACKGROUND

Formulae of estimated glomerular filtration rate (eGFR) based on serum creatinine (Scr) are routinely used in oncology patients, however, they are inaccurate in some populations. Our aim was to assess the agreement of eGFR formulae and thereby build a nomogram to predict the reliability of estimates.

METHODS

Measured GFR (mGFR) using isotope from 445 oncology patients were compared with eGFR from six formulae (Cockcroft-Gault, Modification of Diet in Renal Disease (MDRD), modified MDRD formulae for Chinese (C-MDRD), Chronic Kidney Disease Epidemiology (CKD-EPI) Collaboration, Wright and full age spectrum (FAS)). Bias, precision and accuracy of eGFR formulae were examined. We also evaluated statistics of agreement: the total deviation index (TDI), the concordance correlation coefficient (CCC) and the coverage probability (CP). Multivariate logistic regression was applied to identify characteristics associated with inaccurate eGFR and construct a predictive nomogram.

RESULTS

All eGFR formulae tended to overestimate the eGFR. The percentage of patients with eGFR within 30% the mGFR ranged from 38.0 to 62.8%. Cockcroft-Gault and MDRD showed low bias and high precision. The MDRD formula exhibited lowest TDI, meaning that 90% of estimations ranged from - 36 to 36% of mGFR. Multivariate logistic regression showed that inaccuracy of MDRD was found in elderly patients or in patients with eGFR greater than 120 ml/min. A nomogram was constructed to help oncologists to predict the risk of inaccuracy of eGFR. The calibration curve showed good agreement.

CONCLUSIONS

Our results suggest that the error of eGFR by any formulae was common and wide in Chinese oncology patients. Our nomogram may assist oncologists in decision-making when mGFR is needed.

Assessing the impact of inadequate hydration on isotope-GFR measurement

Guidelines state that patients undergoing isotope glomerular filtration rate (GFR) tests should maintain adequate hydration, but pragmatically these tests can coincide with procedures requiring the patient not to eat or drink ('nil-by-mouth') for up to 12 hours beforehand. This study investigated the impact of a 12-hour nil-by-mouth regime on GFR measurement. Twelve healthy volunteers were recruited from our institution. Exclusion criteria included diabetes mellitus, being under 18 years of age and pregnancy. Isotope GFR measurements were carried out on these volunteers twice. One of the tests adhered strictly to the British Nuclear Medicine Society (BNMS) guidelines for GFR measurement and the other test was carried out after the volunteers had refrained from eating or drinking anything for 12 hours. The order of these tests was randomly assigned. The results show that after a nil-by-mouth regime, participants' average absolute GFR fell from 108 ml/min to 97 ml/min (p < .01), while normalised GFR fell from 97 ml/min/1.73 m² to 88 ml/min/1.73m² (p < .01). Serum creatinine rose from 68 mmol/L to 73 mmol/L (p < .05). There were no changes in blood pressure, serum hydration markers or bio-impedance measured fluid status. Urine analysis showed statistically significant increases in urea, creatinine and osmolality levels after the nil-by-mouth regime. The results highlight the importance of following current guidelines recommending fluid intake during the procedure. Practitioners should consider what other outpatient appointments are being scheduled concurrently with a GFR test.

Carboplatin dose based on actual renal function: no excess of acute haematotoxicity in adjuvant treatment in seminoma stage I

Introduction

The practice of carboplatin dosing is not concordant among different centres and oncologists. Some clinical guidelines recommend capping of the carboplatin dose at, for example, creatinine-clearance (Crea-Cl) of 125 mL/min because of concerns of excessive toxicity. Clinical data to support such recommendations are lacking, especially in patients with seminoma.

Methods

This is a retrospective analysis of acute haematotoxicity of patients with stage I seminoma treated with adjuvant carboplatin area under the curve (AUC) 7 in routine practice in two Swiss centres in 2005–2015, and a comparison of incidence and grade (according to Common Terminology Criteria for Adverse Events v4.0) of haematological adverse events (hAEs) in patients with Crea-Cl <125 mL/min vs >125 mL/min without dose capping.

Results

74 patients with 229 documented measurements were included (median 3/patient). A total of 151 hAEs occurred. Platelet nadir occurred earlier than median white cell/neutrophil count (median day 15 vs day 22; P<0.0001). The majority of hAEs were mild, with more than 80% being of grade 1. Only two (2.7%) clinically relevant hAEs necessitating subsequent interventions occurred (one patient received platelet transfusion, one patient with febrile neutropaenia). Haematological toxicities were not statistically different in patients dosed with Crea-Cl >125 mL/min versus those with Crea-Cl <125 mL/min. No hAEs other than grade 1 occurred before day 10 and after day 24.

Conclusions

Toxicity after single-dose carboplatin AUC 7 is generally mild. No excess of toxicity occurs in patients with high Crea-Cl above 125 mL/min, and therefore dose capping is not routinely necessary. In addition, this study provides a rationale for efficient use of healthcare services without compromising patients’ safety.

Monitoring the estimated glomerular filtration rate (eGFR) in patients with small-cell lung cancer during chemotherapy: equations based on serum creatinine or cystatin C?

BACKGROUND

This study compared the differences between the estimated glomerular filtration rate (eGFR) calculated by several equations based on serum creatinine (Scr) and cystatin C (CysC) concentrations for monitoring renal function in patients with small-cell lung cancer (SCLC) during chemotherapy.

METHODS

Seventy-one patients with SCLC were retrospectively analyzed. The eGFR before and after each chemotherapy cycle was calculated by the following equations: the chronic kidney disease epidemiology collaboration (CKD-EPI) equation, the modification of diet in renal disease (MDRD) equation, the Cockcroft-Gault (CG) equation, and five CysC-based equations. The patients were compared among the different eGFR groups.

RESULTS

The mean decreases in eGFR_CKD-EPI (-2.25 ± 9.89 ml/min/1.73 m²) between each treatment cycle were more significant than the decreases in eGFR_CG (-0.46 ± 10.17 ml/min/1.73 m²), eGFR_MDRD (-0.48 ± 9.79 ml/min/1.73 m²), and five calculated eGFR_CysC (p < 0.05). Single-/multiparameter analyses showed that patients with a higher body mass index (BMI >23) and receiving more treatment cycles (>3) were at increased risk for developing renal impairment with an eGFR less than 60 ml/min/1.73 m² during chemotherapy.

CONCLUSIONS

The eGFR calculated by the CKD-EPI equation changed more significantly between each chemotherapy cycle than did the eGFR from the other equations based on Scr or CysC in patients with SCLC. Oncologists should pay more attention to the renal function of specific patient groups during treatment.

Effect of Renal Dysfunction on Toxicity in Three Decades of Cancer Therapy Evaluation Program-Sponsored Single-Agent Phase I Studies

PURPOSE

Alterations in renal clearance of anticancer drugs can affect the occurrence of toxicities related to drug exposure. The National Cancer Institute and the US Food and Drug Administration (FDA) use different criteria to classify renal dysfunction. We examined those discrepancies and their potential association with the incidence of toxicities in patients enrolled onto Cancer Therapy Evaluation Program-sponsored single-agent phase I studies over three decades (1979 to 2010).

METHODS

Data to estimate creatinine clearance according to the Cockcroft-Gault and Jelliffe formulas were available from 10,236 patients, and data to estimate creatinine clearance according to the six- and four-variable Modification of Diet in Renal Disease formulas were available from a subset (n = 4,084). Patients were classified according to National Cancer Institute and FDA criteria, and the rates of clinically relevant toxicities were evaluated within groups and compared among groups.

RESULTS

Cockcroft-Gault estimated renal function improved over time, which may be attributed to an increase in weight of patients in the same time frame. Approximately 36% of patients enrolled onto phase I trials had mild renal dysfunction by FDA criteria. Relative to normal function, mild renal dysfunction was associated with a statistically significant but small increase in grade 3 or 4 nonhematologic toxicity and any relevant toxicities.

CONCLUSION

Patients with mild renal dysfunction by FDA criteria have routinely been enrolled onto phase I studies of antineoplastics without clinically meaningful increase in the risk of toxicity. In future oncology renal dysfunction trials based on the FDA classification, the FDA mild group may only need to be activated when the moderate and normal groups differ substantially in tolerability or pharmacokinetics.

Comparison of glomerular filtration rate measured by plasma sample technique, Cockroft Gault method and Gates' method in voluntary kidney donors and renal transplant recipients

Background:

There are numerous methods for calculation of glomerular filtration rate (GFR), which is a crucial measurement to identify patients with renal disease.

Aims:

The aim of this study is to compare four different methods of GFR calculation.

Settings and Design:

Clinical setup, prospective study.

Materials and Methods:

Data was collected from routine renal scans done for voluntary kidney donors (VKD) or renal transplant recipients 6 months after transplantation. Following technetium-99m diethylene triamine penta acetic acid injection, venous blood samples were collected from contralateral arm at 120, 180, and 240 min through an indwelling venous cannula and direct collection by syringe. A total volume of 1 ml of plasma from each sample and standards were counted in an automatic gamma counter for 1 min. Blood samples taken at 120 min and 240 min were used for double plasma sample method (DPSM) and a sample taken at 180 min for single plasma sample method (SPSM). Russell's formulae for SPSM and DPSM were used for GFR estimation. Gates’ method GFR was calculated by vendor provided software. Correlation analysis was performed using Pearson's correlation test.

Results:

SPSM correlated well with DPSM. GFR value in healthy potential kidney donors has a significant role in the selection of donors. The mean GFR ± (standard deviation) in VKD using SPSM, DPSM, camera depth method and Cockroft Gault method was 134.6 (25.9), 137.5 (42.4), 98.6 (15.9), 83.5 (21.1) respectively. Gates’ GFR calculation did not correlate well with plasma sampling method.

Conclusions:

Calculation of GFR plays a vital role in the management of renal patients, hence it was noted that Gates GFR may not be a reliable method of calculation. SPSM was more reliable. DPSM is reliable but cumbersome. It is difficult to accurately calculate GFR without a gold standard.

Dosing of cytotoxic chemotherapy: impact of renal function estimates on dose

BACKGROUND

Oncology clinicians are now routinely provided with an estimated glomerular filtration rate on pathology reports whenever serum creatinine is requested. The utility of using this for the dose determination of renally excreted drugs compared with other existing methods is needed to inform practice.

PATIENTS AND METHODS

Renal function was determined by [Tc(99m)]DTPA clearance in adult patients presenting for chemotherapy. Renal function was calculated using the 4-variable Modification of Diet in Renal Disease (4v-MDRD), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), Cockcroft and Gault (CG), Wright and Martin formulae. Doses for renal excreted cytotoxic drugs, including carboplatin, were calculated.

RESULTS

The concordance of the renal function estimates according to the CKD classification with measured Tc(99m)DPTA clearance in 455 adults (median age 64.0 years: range 17-87 years) for the 4v-MDRD, CKD-EPI, CG, Martin and Wright formulae was 47.7%, 56.3%, 46.2%, 56.5% and 60.2%, respectively. Concordance for chemotherapy dose for these formulae was 89.0%, 89.5%, 85.1%, 89.9% and 89.9%, respectively. Concordance for carboplatin dose specifically was 66.4%, 71.4%, 64.0%, 73.8% and 73.2%.

CONCLUSION

All bedside formulae provide similar levels of concordance in dosage selection for the renal excreted chemotherapy drugs when compared with the use of a direct measure of renal function.

Evaluation of carboplatin dosing in non-small cell lung carcinoma patients using Calvert formula and Cockroft and Gault equation for glomerular filtration rate estimation

The aim of this study was to evaluate the reliability of the Cockroft and Gault (CG) equation for glomerular filtration rate (GFR) estimation in carboplatin dosing based on the Calvert formula. The records of 117 patients with advanced non-small cell lung carcinoma treated with carboplatin were retrospectively analyzed. Theoretical carboplatin doses derived from the Calvert formula using the CG equation were calculated for each chemotherapy cycle. Fluctuations in the theoretical carboplatin doses were analyzed, and discrepancies between actual carboplatin doses prescribed by the physician and theoretical doses were assessed. It was found that, compared with the first-cycle dose, subsequent theoretical doses were more than 10% higher in 79/320 cycles (24.7%) and more than 10% lower in 53/320 cycles (16.6%; P=0.015). A body mass index greater than or equal to 30 was associated with a tendency for increased CG-estimated GFR during subsequent chemotherapy cycles (P=0.009). Physicians tended to lower the prescribed dose (32.2% of the cycles) by using a higher serum creatinine (Scr) level for dose calculation than was actually measured. We concluded that Calvert formula-derived carboplatin doses fluctuate widely during repeated cycles when actual Scr is used for CG-estimated GFR. The measurement of 24-h creatinine clearance is advised as an alternative in selected patients with reduction in serum creatinine observed during treatments.

Carboplatin dose calculation in lung cancer patients with low serum creatinine concentrations using CKD-EPI and Cockcroft-Gault with different weight descriptors

STUDY OBJECTIVES

Carboplatin dosing using the Calvert and Cockcroft-Gault formulae in patients with low serum creatinine levels is discussed controversially. We conducted a retrospective analysis applying the CKD-EPI formula and the alternate size descriptors adjusted body weight and predicted normal weight in the Cockcroft-Gault equation for calculating the carboplatin dose.

METHODS

Data were collected retrospectively from 128 lung cancer patients with serum creatinine <0.8 mg/dL (71 μmol/L) who had received chemotherapy that was mostly platinum-based. Serum creatinine concentration for renal function estimation and measured creatinine clearance (24-h urine collection) were available on the same day from these patients. Actual doses were calculated based on the Cockcroft-Gault formula with total body weight. For the study purpose doses were recalculated using Cockcroft-Gault with adjusted body weight and predicted normal weight and CKD-EPI. Subgroup analyses were performed for gender and body mass index.

RESULTS

All alternate dose calculations were not inferior to the calculation based on Cockcroft-Gault using total body weight. In overweight and obese patients they were superior in reducing mean overdose from 24% to roughly 15% (predicted normal weight, CKD-EPI) and 10% (adjusted body weight) and from 25% to 9%, 8% and 4%, respectively. Best performed the combination of Cockcroft-Gault with adjusted body weight.

CONCLUSION

The results show that application of the alternate size descriptor adjusted body weight in the Cockcroft-Gault equation can improve dosing accuracy especially in overweight and obese patients with low serum creatinine levels.

Very high GFR in cancer patients undergoing chemotherapy: prevalence, carboplatin dosing patterns and chemotherapy toxicity

AIM

Carboplatin dosing depends on accurate glomerular filtration rate (GFR) estimation. There is a lack of clinical agreement about carboplatin dosing when the GFR measurement is very high (>110 mL/min).

METHODS

A retrospective audit of pre-chemotherapy 99m technetium (Tc) diethylenetriamene pentaacetate (DTPA) radionuclide GFR estimations and patients' chart review were performed from January 2006 to May 2009. The primary objective was to determine the prevalence of patients with a high GFR and the incidence of myelotoxicity in this group.

RESULTS

Overall 18 of 148 treated patients (14%) measured GFR >110mL/min. The GFR values of six of the 18 patients were capped for dose calculation. In eight patients a measured GFR corrected for body surface area was used and in four the actual measured GFR was used for dose calculation. In total, 63 cycles of chemotherapy were delivered. Grade III or IV myelotoxicity accounted for 37% (15/41) of all myelotoxicities. Neutropenia accounted for almost 39% of all myelotoxicities (16/41). Two patients (11%) were hospitalized due to febrile neutropenia. Eight patients (40%) had dose reduction and four (20%) had treatment delays due to myelotoxicity. The frequency of myelotoxicity was high irrespective of the GFR used (corrected or uncorrected) in calculating the chemotherapy dose.

CONCLUSION

High values of GFR, by 99mTc DTPA radionuclide measurement, are a common finding in pre-chemotherapy patients irrespective of age. Carboplatin dosing patterns in this group of patients vary among treating oncologists and a standardized approach is needed.

Estimation of renal function in lung cancer patients

INTRODUCTION

In lung cancer patients treated with chemotherapy, renal function is an important parameter to be monitored. Since measurement of renal function with either isotope or creatinine clearance is time consuming and expensive, we evaluated which of the following equations: Cockcroft-Gault (CG), Wright, modification of diet in renal disease equation (MDRD), MDRD adjusted for body surface area (BSA) and chronic kidney disease epidemiology collaboration (CKD-EPI) best resembles endogenous creatinine clearance (ECC) and could therefore replace its measurement in clinical practice.

METHODS

218 lung cancer patients, who had their 24-h creatinine secretion in urine measured prior to the start of any chemotherapy, were included. Estimation of renal function was calculated and compared to ECC.

RESULTS

There were no major differences in the performance of the tested equations. Mean percentage error of more than 20% and general underestimation was common to all equations. Wright equation performed best although it describes only 43% of ECC variability. Mean measured ECC was 94 mL/min (95% confidence interval [CI]: 90-98 mL/min) and 90 mL/min for Wright equation (95% CI: 87-93 mL/min) (Supp. Fig. 3). MDRD and CKD-EPI equation performed poorest since they do not include any body size descriptor. Large deviations of differences were observed, with a median standard deviation of more than 20% and deviations from ECC exceeding 100%. Wright equation performed best, whereas, despite their leading role in the detection of renal diseases, the MDRD and CKD-EPI equation performed poorest since they do not include any body size descriptor. In the range of ECC<50 mL/(min×1.73 m(2)), the CG equation most often detected a contraindication for cisplatin use. Differences between ECC and calculated values correlated with patients' weight, BSA and body mass index when these were not included in the equation itself.

CONCLUSIONS

In evaluating the renal function of lung cancer patients, equations adjusted for body size descriptors should be preferred. Estimated renal function should be interpreted against the characteristics of patient's body size and special attention is needed when these are reaching the extremes.

Evaluation of glomerular filtration rate estimation by Cockcroft-Gault, Jelliffe, Wright and Modification of Diet in Renal Disease (MDRD) formulae in oncology patients

BACKGROUND

The aim was to evaluate the accuracy of Cockcroft-Gault, Jelliffe, Wright and Modification of Diet in Renal Disease (MDRD) formulae as a substitute for the gold standard measure of glomerular filtration rate (GFR) using chromium 51 EDTA.

PATIENTS AND METHODS

Retrospective analysis of GFR measurements in oncology patients from a University Teaching Hospital over 3 years was carried out. Bias and precision of estimates of GFR were compared with measured GFR.

RESULTS

Six hundred and sixty patients with measured GFR (median 90 ml/min, range 23-179 ml/min) were identified. Cockcroft-Gault produced the smallest bias (median percentage error -1.4%) and highest precision (median absolute percentage error 14.0%) and was the most accurate for carboplatin dosing. For patients>30% over their ideal body weight (IBW), using IBW+30% in the Cockcroft-Gault formula was more precise than using actual body weight or IBW. The Wright formula was most accurate for patients aged 70+years and patients with a body mass index (BMI)≥30 but overestimated GFR when GFR<50 ml/min.

CONCLUSIONS

When measured GFR is unavailable, we advise estimating GFR using the Cockcroft-Gault formula and using IBW+30% for patients weighing>30% over their IBW. If the GFR is ≥50 ml/min and the patient is >70 years and/or BMI≥30, the Wright formula gives the best estimate of GFR.

Effect of age on systemic exposure and haematological toxicity of carboplatin in advanced non-small cell lung cancer patients

The aim of this study was to evaluate systemic exposure to carboplatin and its haematological toxicity in patients with advanced non-small cell lung cancer both older and younger than 70 years when the target area under the curve (AUC) in elderly patients was reduced by 20%. For this purpose, a population pharmacokinetic model was developed and the haematological toxicity of the drug was assessed. A total of 33 patients received carboplatin on day 1 and gemcitabine (1250 mg/m(2) ) on days 1 and 8. This schedule was repeated every 21 days. The Calvert-Crokcoft-Gault formula was employed to calculate a dose of carboplatin with a target AUC of 5 mg/min./mL in patients under 70 years and 4 mg/min./mL in patients aged 70 or older. The data of 24 patients were treated for population modelling performed with the nonmem (University of California, San Francisco, CA, USA) approach. Haematological toxicity was evaluated for all 33 patients enrolled in the study. The carboplatin systemic exposure measured by the AUC (mg/min./mL) was 5.98 (5.45; 6.51) and 5.36 (5.02; 5.69) for the younger patients and older groups, respectively. No significant differences were observed between the two groups with respect to rates of grade 3+ anaemia, neutropenia or thrombocytopenia. In clinical practice, a target AUC of 4 mg/min./mL carboplatin is applied to patients aged 70 and over, but the actual systemic exposure to the drug is higher. This supports a target AUC of 4 mg/min./mL carboplatin for patients older than 70 years when the dose is calculated by means of the Calvert-Crokcoft-Gault formula.

Renal safety of ibandronate 6 mg infused over 15 min versus 60 min in breast cancer patients with bone metastases: a randomized open-label equivalence trial

PURPOSE

The aim of this study was to demonstrate the renal safety equivalence of ibandronate 6 mg infused over 15 min versus 60 min, in patients with bone metastases of breast cancer.

PATIENTS AND METHODS

Patients were females having breast cancer with at least one bone metastasis. Exclusion criteria were renal failure (creatinine clearance < 30 mL/min), tooth/jaw disorder or uncontrolled severe disease. Eligible patients were randomly assigned to receive nine ibandronate 6 mg i.v. infusions over either 15 min or 60 min. The primary outcome was the 95% confidence interval (CI) of the difference in creatinine clearance between groups, 28 days after the last infusion. The equivalence margin was ±8 mL/min.

RESULTS

Overall 334 patients were randomized (165-15 min infusions vs. 169 to 60 min infusions, 325 (159 vs. 166) were analyzed by intent-to-treat, and 312 (151 vs. 161) were analyzed per protocol. Per protocol, the 15 min-60 min difference in creatinine clearance [95% CI] was -3.00 [-8.18, 2.18]. By intent-to-treat, this difference was-2.91 [-7.99, 2.16]. Death and serious adverse event rates did not differ between groups. Three serious adverse events were considered related to ibandronate: an osteonecrosis of the jaw (15-min group), a pain in jaw and an enamel cracking (60-min group). Two renal failures, reported in the 60 min group, were not considered related to ibandronate. None occurred in the 15 min group.

CONCLUSION

Ibandronate may be infused over 15 min without clinically significant consequence on renal safety.

Acute renal problems in the critically ill cancer patient

PURPOSE OF REVIEW

This review addresses three major topics relevant for the management of renal problems in the critically ill cancer patient; the assessment of kidney function in patients with cancer, serious water and electrolyte metabolism disturbances and acute kidney injury secondary to hematological and nonhematological malignancies.

RECENT FINDINGS

In all cancer patients, renal function (urinalysis for proteinuria or albuminuria and serum creatinine to estimate glomerular filtration rate) should be tested when they first present, at initiation and change of cancer therapy as well as during follow-up. However, the different proposed formulae for estimation of the glomerular filtration rate should be used with caution. Electrolyte abnormalities associated with the refeeding syndrome are common, yet underappreciated, and occur typically in acutely ill, malnourished hospitalized patients who are administered intravenous or enteral nutrition. Currently available data on acute kidney injury and its consequences suggest that acute kidney injury has the potential to substantially alter the outcome of patients with cancer and jeopardize their chances of receiving optimal cancer treatment and a potential cure.

SUMMARY

The complex management of the numerous renal complications of the critically ill cancer patient needs a multidisciplinary approach in which the nephrologist, intensivist and oncologist all play a pivotal role.

Incremental value of renal function in risk prediction with the Seattle Heart Failure Model

BACKGROUND

Impaired renal function portends poor heart failure (HF) outcomes. The Seattle Heart Failure Score (SHFS), a multimarker risk assessment tool, however does not incorporate renal function. In this study, we assessed the incremental value of renal function over the SHFS in patients with advanced HF on contemporary optimal treatment.

METHODS

Blood urea nitrogen (BUN), serum creatinine (sCr), BUN/sCr ratio, and estimated glomerular filtration rate were assessed in survival models with SHFS as the base model among 443 patients with HF (52 +/- 12 years, male 68.5%, white 52.4%, ejection fraction 0.18 +/- 0.08). Incremental value of renal function was assessed by changes in the likelihood ratio chi(2) and the area under the receiver operating characteristic curves for 1-, 2-, and 3-year event prediction.

RESULTS

During a median follow-up of 21 months, 108 (24.5%) of 443 patients had an event (death [n = 92], urgent transplantation [n = 13], or ventricular assist device implantation [n = 3]). All renal parameters individually were associated with outcome (BUN, P < .001; sCr, P < .001; BUN/sCr ratio, P = .006; and estimated glomerular filtration rate, P = .006); however, only BUN was an independent predictor of events in multivariable analyses. Addition of BUN improved the predictive ability of SHFS (Deltalikelihood ratio chi(2) 5.03, P = .025); however, the increase in the area under the receiver operating characteristic curve was marginal (year 1, 0.786 to 0.791; year 2, 0.732 to 0.741; year 3, 0.745 to 0.754; all P > .2).

CONCLUSION

Among the various renal function parameters, BUN had the strongest association with outcomes in patients with advanced HF. However, the incremental value of renal function over the SHFS for risk determination was marginal.

Human renal function maturation: a quantitative description using weight and postmenstrual age

This study pools published data to describe the increase in glomerular filtration rate (GFR) from very premature neonates to young adults. The data comprises measured GFR (using polyfructose, (51)Cr-EDTA, mannitol or iohexol) from eight studies (n = 923) and involved very premature neonates (22 weeks postmenstrual age) to adulthood (31 years). A nonlinear mixed effects approach (NONMEM) was used to examine the influences of size and maturation on renal function. Size was the primary covariate, and GFR was standardized for a body weight of 70 kg using an allometric power model. Postmenstrual age (PMA) was a better descriptor of maturational changes than postnatal age (PNA). A sigmoid hyperbolic model described the nonlinear relationship between GFR maturation and PMA. Assuming an allometric coefficient of 3/4, the fully mature (adult) GFR is predicted to be 121.2 mL/min per 70 kg [95% confidence interval (CI) 117-125]. Half of the adult value is reached at 47.7 post-menstrual weeks (95%CI 45.1-50.5), with a Hill coefficient of 3.40 (95%CI 3.03-3.80). At 1-year postnatal age, the GFR is predicted to be 90% of the adult GFR. Glomerular filtration rate can be predicted with a consistent relationship from early prematurity to adulthood. We propose that this offers a clinically useful definition of renal function in children and young adults that is independent of the predictable changes associated with age and size.

Novel algorithm for more accurate calculation of renal function in adults with cancer

BACKGROUND

Cytotoxic agents have a narrow therapeutic window. A high percentage of some of them is renally excreted in unchanged form. Accurate assessment of an individual's glomerular filtration rate (GFR) helps to predict the pharmacokinetic behavior of those drugs more precisely. GFR calculations, however, have their limitations.

OBJECTIVE

To establish a more accurate calculation of renal function over a broad range of constitutive GFR values.

METHODS

Patients with cancer were included in the analysis. Serum levels of cystatin C, creatinine, urea, albumin, and beta-trace protein were measured, and GFR was calculated by 8 mathematical formulas. The results were compared with creatinine clearance (CrCl) calculated from timed urine specimens.

RESULTS

One hundred two patients were evaluated: median age, 57.5 years (range 20-91); females, 52; males, 50; and mean urinary CrCl, 77.0 mL/min. The bias (mean percentage error) was -2% and the precision (mean absolute percentage error) was 23% for the Modification of Diet in Renal Disease (MDRD) estimation of GFR. All equations significantly overestimated CrCl in patients with measured clearance less than 50 mL/min (p < 0.05), with the exception of the modified Salazar-Corcoran formula. All equations underestimated CrCl in patients with measured clearance greater than 100 mL/min. The Wright formula was the least biased and most precise (-5%, 16%, respectively). In patients with measured CrCl 50-100 mL/min, the MDRD calculation had a bias of -4% and a precision of 17%. The Jelliffe and Larsson equations were associated with significant sex bias (p < 0.05).

CONCLUSIONS

These observations suggest that individual GFR values over a broad range cannot be calculated accurately enough with only one selected formula. It may be useful to classify renal function of patients with cancer according to the novel algorithm by using MDRD first and then to subsequently calculate GFR in higher and lower ranges with the Wright and modified Salazar-Corcoran formulas, respectively. This algorithm should be validated using larger numbers of patients.

Comparison of glomerular filtration rate measurements with the two plasma sample and single plasma sample, gamma camera Gates, creatinine clearance, and prediction equation methods in potential kidney donors with normal renal function

OBJECTIVE

To compare measured glomerular filtration rate (GFR) by single plasma sample methods (SPSMs), gamma camera Gates, 24-h endogenous creatinine clearance, and prediction equations (Cockcroft-Gault and modification of renal disease (MDRD)) with the two plasma sample method (TPSM) considered as the reference in potential kidney donors with normal renal function.

METHODS

One hundred and fifteen subjects (50 male, 65 female; mean age 41.9+/-12.2 years) with normal renal function were prospectively included in this study. GFR was calculated by TPSM (120-min and 240-min samples) and SPSM (180-min sample).

RESULTS

While there was strong statistically significant correlation between the TPSM and all SPSMs, low correlation was found in Gates, creatinine clearance, Cockcroft-Gault and MDRD. In all SPSMs, 95% limits of agreements were consistent with each other and within clinically acceptable limits. The lowest bias, median absolute difference, mean percentage error, and the best precision were found for Christensen and Groth's method as modified by Watson (CGmW).

CONCLUSIONS

Among the SPSMs, CGmW can reflect GFR more accurately than the other methods. Neither the gamma camera Gates method nor the creatinine clearance method nor the prediction equations (Cockcroft-Gault and MDRD) could calculate GFR accurately. All these techniques could result in mistakes in the management of potential kidney donors.

Renal insufficiency in elderly cancer patients: International Society of Geriatric Oncology clinical practice recommendations

BACKGROUND

Elderly cancer patients commonly have renal function decline. This warrants particular caution during the administration of renally excreted cancer drugs or those with established nephrotoxicity.

DESIGN

An International Society for Geriatric Oncology task force was formed to discuss treatment recommendations for this group of patients.

RESULTS

Before drug therapy, the assessment and optimization of hydration status and evaluation of renal function is required. Serum creatinine alone is insufficient as a means of evaluating renal function, and creatinine clearance should at least be calculated in every patient by the abbreviated modification of diet in renal disease or Cockcroft-Gault equations. In the extremes of obesity and cachexia and at very high and low creatinine values, no single tool is really accurate. In these patients, the best estimate of glomerular filtration rate is provided by direct methods such as (51)Cr-EDTA or inulin measurement. Within each drug class, preference may be given to agents less likely to be influenced by renal clearance, which are minimally nephrotoxic, or for which appropriate methods of prevention for renal toxicity exist. Coadministration of known nephrotoxic drugs should be avoided or minimized.

CONCLUSIONS

Future trials should be designed to present data in a way that allows evaluation of the contribution of renal function to toxicity and efficacy.

Nadroparine activated fibrinolysis and improvement of glomerular filtration rate in patients with FIGO IIB–IIIB cervical cancer treated with radiochemotherapy

OBJECTIVES

(1) Evaluation of the influence of hemostatic disorders on renal function in patients with FIGO stage IIB-IIIB cervical cancer treated with radiochemotherapy. (2) Identifying methods of improving renal function in this patients group.

METHODS

Treatment design assumes the administration of a total radiation dose of 46-65 Gy and, additionally, cisplatin 40 mg/m2 every 7 days in patients with normal plasma creatinine level. Renal function was assessed with the aid of dynamic scintigraphy with glomerular filtration rate (GFR) evaluation. Analysis of serum hemostatic system covered D-dimers, PAP, PAI-1, tPA, FDP, F1+2 and TAT. The same hemostatic parameters were also evaluated in urine. The patients were divided into two groups: the study group - i.e. patients with affected GFR and the control group - with normal GFR. Half of study group patients, throughout the entire treatment, receive nadroparine 2850 units aXa/0.3 ml every 24 h during and 6 weeks after the treatment.

RESULTS

There are significant decreases of GFR in control (median -9.7%) and study group without nadroparine (median -9.9%) and increase in the GFR (median 22.3%) in study group with nadroparine (p=0.0001). Plasma and urine hemostatic parameter analysis showed activation of fibrinolysis in patients treated with nadroparine and fibrinolysis inhibition in remaining groups.

CONCLUSIONS

(1) Inhibition of fibrinolysis may cause subclinical renal insufficiency in patients with advanced cervical cancer. (2) Insufficiency increases after the end of radiochemotherapy in patients, as well with normal GFR as, with primary decreased GFR. (3) Application of nadroparine causes fibrinolysis activation, and increase in the GFR.

Drawbacks and Prognostic Value of Formulas Estimating Renal Function in Patients With Chronic Heart Failure and Systolic Dysfunction

BACKGROUND

Renal function is an important risk marker for morbidity and mortality in chronic heart failure (CHF) and is often estimated with the use of creatinine-based formulas. However, these formulas have never been validated in a wide range of CHF patients. We validated 3 commonly used formulas estimating glomerular filtration rate (GFR) with true GFR in CHF patients. Furthermore, we compared the prognostic value of these formulas for cardiovascular outcome with that of true GFR during 12 months of follow-up.

METHODS AND RESULTS

In 110 CHF patients (age, 57+/-11.7 years; left ventricular ejection fraction, 0.27+/-0.09; NYHA class, 2.5+/-0.9), we measured 125I-iothalamate clearance. Cockcroft-Gault (GFR(cg)), Modification of Diet in Renal Disease (MDRD), and simplified MDRD (sMDRD) equations were used as creatinine-based renal function estimations. Furthermore, 24-hour creatinine clearance (CrCl) was determined. CrCl and GFR(cg) were the most accurate. MDRD was most precise formula, although it was also highly biased. All formulas overestimated in the lower ranges and underestimated in the upper ranges of the GFR corrected for body surface area. The predictive performance of the formulas was best in severe CHF (NYHA classes III and IV). The prognostic value of CrCl and MDRD for cardiovascular outcome was comparable to that of GFR, the sMDRD was slightly less, and the GFR(cg) had a significantly worse prognostic value.

CONCLUSIONS

In the more severe ranges of CHF, creatinine-based formulas and CrCl corrected for body surface area appeared to be more precise and accurate in estimating true GFR corrected for body surface area. The MDRD formula is the most precise and has a good prognostic value, whereas the sMDRD is slightly less accurate but uses fewer parameters, which makes this formula a practical alternative in clinical practice.

Renal toxicities of chemotherapy

Chemotherapeutic agents can produce a variety of acute and chronic organ toxicities. Since many antitumor drugs and their metabolites are cleared renally, the kidneys are vulnerable to injury. The drugs involved will determine the site of injury within the kidney, resulting in clinical manifestations ranging from an asymptomatic rise in serum creatinine to acute renal failure. The most common renal toxicities of chemotherapeutic agents are described.

Difference of carboplatin clearance estimated by the Cockroft–Gault, Jelliffe, Modified-Jelliffe, Wright or Chatelut formula

OBJECTIVE

Although the Calvert formula is the standard method to calculate the dose of carboplatin, there is no consensus how to determine the glomerular filtration rate (GFR) without using [51Cr]-ethylenediamine tetraacetic acid (51Cr-EDTA). Creatinine clearance (Ccr), calculated using the Cockroft-Gault, Jelliffe, Modified-Jelliffe or Wright formulae, has been used as a substitute for the GFR. In addition to these four formulae, the Chatelut formula has been proposed as a way to calculate carboplatin clearance. Among these formulae, Jelliffe formula does not include body surface area (BSA) or body weight to adjust the body size and thus may have greater bias than the other four formulae in estimating carboplatin clearance. The purpose of this study is to evaluate if these five formulae could equally estimate the carboplatin clearance.

METHODS

: Carboplatin clearance was estimated in 253 patients with gynecologic cancer who received carboplatin-based chemotherapy between January 1996 and August 2004. Ccr was estimated using the Cockroft-Gault, Jelliffe, Modified-Jelliffe or Wright formulae. Carboplatin clearance was also calculated directly by using the Chatelut formula. The five estimations of carboplatin clearance were compared with each other using the post-hoc Wilcoxon signed rank test. The median percent error (MPE) and the median absolute percent error (MAPE) were evaluated by comparing carboplatin clearance. The relationships between BSA and ratios of estimated carboplatin clearance (Jelliffe/Cockroft-Gault, Jelliffe/Modified-Jelliffe, Jelliffe/Wright, Jelliffe/Chatelut) were evaluated by using simple regression.

RESULTS

: The estimated carboplatin clearances were: Cockroft-Gault formula, 109.8 +/- 28.4; Jelliffe formula, 128.5 +/- 28.2; Modified-Jelliffe formula, 110.8 +/- 25.7; Wright formula, 112.2 +/- 24.3; Chatelut formula, 114.1 +/- 33.0. A statistically significant difference was observed between carboplatin clearance calculated using Jelliffe formula and that given by each of the other four formulae. Comparing the results of the Cockroft-Gault formula with the Jellife, Modified-Jelliffe, Wright and Chatelut formulae yielded MPEs of +19%, +2%, +3% and +3% and MAPEs of 27%, 5%, 6% and 6%, respectively. There was a significant correlation between BSA and ratio of estimated carboplatin clearance (Jelliffe/Cockroft-Gault, Jelliffe/Modified-Jelliffe, Jelliffe/Wright, Jelliffe/Chatelut), with Pearson correlation coefficients of 0.928, 0.847, 0.965 and 0.839 respectively. As the BSA of patient became smaller, the differences between the carboplatin clearance calculated by the Jelliffe formula from other four formulas became larger.

CONCLUSIONS

: Estimates of carboplatin clearance calculated by the Jelliffe formula tend to have greater positive bias compared to the other four formulae, particularly when the BSA of the patient is small. In order to conduct collaborative international studies, it may be necessary to standardize the formula used to estimate carboplatin clearance to perform international collaboration studies.

Accurate measurement of individual glomerular filtration rate in cancer patients: an ongoing challenge

A narrow therapeutic index is a characteristic feature of cytotoxic agents. Some of these agents are almost entirely eliminated renally in unchanged active form. As a consequence, assessment of the individual glomerular filtration rate (GFR) may help to predict the pharmacokinetic behaviour of cytotoxic agents in plasma more precisely. In addition, GFR-adapted individualization of cancer chemotherapy may have an enormous impact on the severity of side effects. Several methods are available to determine GFR or creatinine clearance (CrCl). GFR-measurement based on experimental methods with radiolabelled isotopes, contrast media or inulin helps to reflect the real situation very closely. In addition, 24-h urine collection is a convenient and feasible method to measure creatinine clearance. Finally, several mathematical equations exist to estimate GFR or CrCl based on serum creatinine and other parameters. Only a few of these equations have been developed in oncologic patients. However, some of these equations are routinely used in clinical practice, because they allow a rapid estimation of GFR. Based on the fact that clinically relevant differences have been assessed between calculated values and the real situation, mathematical calculation of GFR or CrCl does not seem to be appropriate to assess individual renal function precisely enough over a broad range of individual GFR or CrCl. Whether the measurement of low-molecular-weight proteins, such as cystatin C and ss-trace protein, may help to reflect the real situation more precisely is a matter of controversial debate.

Incidence of renal insufficiency in cancer patients

The frequency of chronic renal insufficiency among cancer patients is unclear. The aim of this study was to determine the frequency of impaired renal function within a population of cancer patients. One thousand two hundred seventeen patients (563 women, 654 men) with cancer underwent serum creatinine concentration and glomerular filtration rate (GFR) evaluations. The Cockcroft-Gault formula was used to estimate the GFR from the creatinine clearance (Cl(cr)). Renal insufficiency was defined as a GFR <or=90 mL/min. Among this population, 72 (5.9%) demonstrated an abnormal serum creatinine concentration (>1.2 mg/dL). According to the Cockcroft-Gault formula evaluations, however, 330 (27.1%) of the patients had an estimated GFR <90 mL/min. Among these, the Clcr was between 60 and 89 mL/min in 241 patients (19.8%); 30 and 59 mL/min in 75 patients (6.2%); and 15 and 29 mL/min in 7 patients (0.6%); 7 patients (6%) had a Cl(cr) <15 mL/min. As a result, 21.2% of patients demonstrating a normal serum creatinine level had abnormal renal function. Renal function should be evaluated in all cancer patients, regardless of their serum creatinine level, before any drug regimen is administered. The Cockcroft-Gault formula appears to be more accurate than serum creatinine concentration for diagnosing renal insufficiency in patients with cancer, but more prospective studies in this population will be necessary to confirm this finding.

Evaluation of the Cockroft-Gault, Jelliffe and Wright formulae in estimating renal function in elderly cancer patients

BACKGROUND

More elderly patients are being treated with chemotherapy. Reliable and accurate measures of renal function are needed to obtain predictable, safe and effective exposure to renally excreted drugs. The Jelliffe, Cockroft-Gault and Wright formulae have been used to evaluate renal function, although they have not been validated in elderly oncology patients. We performed a retrospective evaluation of these formulae using the [51Cr]-ethylenediamine tetraacetic acid ([51Cr]-EDTA) method of measuring glomerular filtration rate (GFR) as the 'gold standard'.

PATIENTS AND METHODS

Inclusion criteria were age > or = 70 years and serum creatinine <250 micromol/l, performed within 4 weeks of glomerular filtration rate (GFR) measurement. Creatinine clearance was calculated using the Cockroft-Gault, Jelliffe and Wright formulae. The precision and accuracy of the three formulae were compared with the gold standard.

RESULTS

Two hundred and twenty-five patients were evaluated: median age, 74 years (range 70-89); males, 108; females, 117; median creatinine, 84 micromol/l (range 44-186). Correlation coefficients of the Jelliffe, Cockroft-Gault and Wright formulae were similar. In the specific GFR ranges of 50-70, 70-90 and 90-120 ml/min, the bias [mean percentage error (MPE)] was +8%, -4% and -13%, respectively. The degree of bias was greater with the Cockroft-Gault and Jelliffe formulae across the same range of GFR with the MPE being -15%, -25%, -32% and -12%, -19% and -23%, respectively. All three formulae have reduced precision and greater bias at the extremes of GFR.

CONCLUSIONS

The Wright formula is the most accurate, precise and least biased formula for the calculation of GFR in elderly patients with a GFR >50 ml/min. These results allow the physician to make a decision regarding the use of the formula based on an expected degree of bias.

Rounding of low serum creatinine levels and consequent impact on accuracy of bedside estimates of renal function in cancer patients

To compare glomerular filtration rate measured by technetium-99m ([Tc^99m]) DTPA clearance with estimated creatinine clearance (CrCl) (Cockcroft and Gault (C&G) method) in patients with serum creatinine (Scr) levels <0.06 mmol l⁻¹, and determine the effect of rounding serum creatinine to 0.06 mmol l⁻¹. Patients with serum creatinine values <0.06 mmol l⁻¹ at the time of [Tc^99m] clearance determination were identified. Creatinine clearance was calculated by the C&G method using both actual and rounded Scr values. A total of 419 adults had GFR measured by technetium-99m diethyl triamine penta-acetic acid ([Tc^99m] DTPA) clearance. Out of this group, 26 patients had a serum creatinine value <0.06 mmol l⁻¹. The C&G estimates of renal function using actual serum creatinine resulted in an overall overestimation of 12.9% when compared to [Tc^99m] DTPA clearance. When the value of serum creatinine was rounded to 0.06 mmol l⁻¹, the formula underestimated renal function by −7.0%. Analysis of estimated creatinine clearance for different levels of renal function showed significant differences to [Tc^99m] DTPA clearance. Rounding up of serum creatinine to 0.06 mmol l⁻¹ improved the predictive ability of the C&G method for the patients with [Tc^99m] DTPA clearance ⩽100 ml min⁻¹, but worsened the effect in those >100 ml min⁻¹. This work indicates that when bedside estimates of renal function are calculated using the C&G formula actual Scr should be used first to estimate CrCl. If the resultant CrCl is ⩽100 ml min⁻¹, then the Scr should be rounded up to 0.06 mmol l⁻¹ and CrCl recalculated. Further assessment of this approach is warranted in a larger cohort of patients.

Estimation of glomerular filtration rate in paediatric cancer patients using 51CR-EDTA population pharmacokinetics

Estimation of glomerular filtration rate (GFR) using the clearance of chromium 51 EDTA ((51)Cr-EDTA) (or other radiolabelled isotopes) is reliable, but invasive and not always practicable. Mathematical models have been devised for estimating GFR using readily obtainable patient characteristics. Unfortunately, these models were developed using various patient populations and may not provide the optimal prediction of GFR in children with cancer. The current study uses population pharmacokinetics to determine the relationship between (51)Cr-EDTA clearance, and patient covariates in 50 paediatric cancer patients. These models were validated using a separate group of 43 children and were compared with previously published models of renal function. Body size was the major determinant of (51)Cr-EDTA clearance and inclusion of weight or surface area reduced the residual variability between individuals (coefficient of variation) from 61 to 32%. Serum creatinine was the only other parameter that significantly improved the model. Mean percentage error values of -5.0 and -1.1% were observed for models including weight alone or weight and creatinine, respectively, with precision estimates of 21.7 and 20.0%. These simple additive models provide a more rationale approach than the use of complex formulae, involving additional parameters, to predict renal function.

Misinterpretation of a Calvert-derived formula leading to carboplatin overdose in two children

Carboplatin is currently recommended to be dosed according to renal function. In adults, dosing by the Calvert formula is based on evidence that carboplatin clearance closely parallels glomerular filtration rate. Several studies have attempted to validate the Calvert formula and its derivations in pediatrics, but no final consensus has been achieved. As a result, different versions of the original formula exist in the pediatric literature. Other factors may also contribute to confusion when applying the formula to young patients, including the manner in which renal function is measured and reported. We describe how misinterpretation of the Calvert formula resulted in carboplatin overdosing in 2 pediatric patients with high-risk neuroblastoma undergoing peripheral blood stem cell transplantation. Measures to avoid such errors have been instituted.