Evaluation of carboplatin dosage based on 4-variable modification of diet in renal disease equation

Carboplatin dosing in the treatment of ovarian cancer: An NRG oncology group study

OBJECTIVE

To determine the effects of using National Comprehensive Cancer Network (NCCN) guidelines to estimate renal function on carboplatin dosing and explore adverse effects associated with a more accurate estimation of lower creatinine clearance (CrCl).

METHODS

Retrospective data were obtained for 3830 of 4312 patients treated on GOG182 (NCT00011986)-a phase III trial of platinum-based chemotherapy for advanced-stage ovarian cancer. Carboplatin dose per patient on GOG182 was determined using the Jelliffe formula. We recalculated CrCl to determine dosing using Modification of Diet in Renal Disease (MDRD) and Cockcroft-Gault (with/without NCCN recommended modifications) formulas. Associations between baseline CrCl and toxicity were described using the area under the receiver operating characteristic curve (AUC). Sensitivity and positive predictive values described the model's ability to discriminate between subjects with/without the adverse event.

RESULTS

AUC statistics (range, 0.52-0.64) showed log(CrClJelliffe) was not a good predictor of grade ≥3 adverse events (anemia, thrombocytopenia, febrile neutropenia, auditory, renal, metabolic, neurologic). Of 3830 patients, 628 (16%) had CrCl <60 mL/min. Positive predictive values for adverse events ranged from 1.8%-15%. Using the Cockcroft-Gault, Cockcroft-Gault with NCCN modifications, and MDRD (instead of Jelliffe) formulas to estimate renal function resulted in a >10% decrease in carboplatin dosing in 16%, 32%, and 5.2% of patients, respectively, and a >10% increase in carboplatin dosing in 41%, 9.6% and 12% of patients, respectively.

CONCLUSION

The formula used to estimate CrCl affects carboplatin dosing. Estimated CrCl <60 mL/min (by Jelliffe) did not accurately predict adverse events. Efforts continue to better predict renal function. Endorsing National Cancer Institute initiatives to broaden study eligibility, our data do not support a minimum threshold CrCl <60 mL/min as an exclusion criterion from clinical trials.

Prevalence of Renal Impairment in Palliative Care Inpatients: A Retrospective Analysis

BACKGROUND AND OBJECTIVE

Multiple drugs used in palliative care, including most opioids or their active metabolites may accumulate in patients with abnormal renal function, leading to serious adverse effects. The incidence and severity of renal impairment in palliative care inpatients has not been evaluated. The aim of the study was to investigate the incidence and severity of renal impairment in palliative care inpatients.

METHODS

A retrospective analysis of medical records of patients admitted to the palliative care ward was performed. Estimated glomerular filtration rate (eGFR) was derived using the Cockcroft-Gault (C-G) and abbreviated Modification of Diet in Renal Disease (aMDRD) equations.

RESULTS

Serum creatinine levels (SCr) were determined in 332 subjects aged 66.4±11.80 years (194 women; mean body mass index [BMI] 22.7±5.21 kg/m(2)). Mean SCr was 107.7±112.31 μmol/L. Elevated SCr (>115 μmol/L) was found in 20.2% of patients. Mean eGFR calculated with C-G and aMDRD equations was 66.6±38.52 mL/min and 78.7±43.55 mL/min/1.73 m(2), respectively. Between 35.2% and 51.8% of patients had eGFR <60 mL/min/1.73 m(2) (depending on the equation used). More than 10% of patients had eGFR <30 mL/min/1.73 m(2). In patients with normal SCr, between 18.9% and 39.2% had eGFR <60 mL/min/1.73 m(2).

CONCLUSION

Renal impairment is common in palliative care inpatients, including considerable number of subjects with moderately to severely reduced kidney function.

Overestimation of carboplatin doses is avoided by radionuclide GFR measurement

BACKGROUND

Glomerular filtration rate (GFR) is used in the calculation of carboplatin dose. Glomerular filtration rate is measured using a radioisotope method (radionuclide GFR (rGFR)), however, estimation equations are available (estimated GFR (eGFR)). Our aim was to assess the accuracy of three eGFR equations and the subsequent carboplatin dose in an oncology population.

PATIENTS AND METHODS

Patients referred for an rGFR over a 3-year period were selected; eGFR was calculated using the Modification of Diet in Renal Disease (MDRD), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) and Cockcroft-Gault (CG) equations. Carboplatin doses were calculated for those patients who had received carboplatin chemotherapy. Bias, precision and accuracy were examined.

RESULTS

Two hundred and eighty-eight studies met the inclusion/exclusion criteria. Paired t-tests showed significant differences for all three equations between rGFR and eGFR with biases of 12.3 (MDRD), 13.6 (CKD-EPI) and 7.7 ml min(-1) per 1.73 m(2) (CG). An overestimation in carboplatin dose was seen in 81%, 87% and 66% of studies using the MDRD, CKD-EPI and CG equations, respectively.

CONCLUSION

The MDRD and CKD-EPI equations performed poorly compared with the reference standard rGFR; the CG equation showed smaller bias and higher accuracy in our oncology population. On the basis of our results we recommend that the rGFR should be used for accurate carboplatin chemotherapy dosing and where unavailable the use of the CG equation is preferred.

Comparative evaluation of the Cockcroft-Gault Equation and the Modification of Diet in Renal Disease (MDRD) study equation for drug dosing: an opinion of the Nephrology Practice and Research Network of the American College of Clinical Pharmacy

Accurate assessment of kidney function is an important component of determining appropriate drug dosing regimens. Nearly all manufacturer-recommended dosage adjustments are based on creatinine clearance ranges derived from clinical pharmacokinetic studies performed during the drug development process. The Cockcroft-Gault (CG) equation provides an estimate of creatinine clearance and is the equation most commonly used to determine drug dosages in patients with impaired kidney function. The Modification of Diet in Renal Disease (MDRD) study equation has also been proposed for this purpose. Published studies report that drug dosages determined by the two equations do not agree in 10-40% of cases. However, interpretation and comparison of these studies are complicated by the variable creatinine methods used for calculating CG and MDRD estimates, the patient populations studied, and a lack of outcomes data demonstrating the clinical significance of dosing discrepancies. Moreover, the impact of reporting standardized serum creatinine values on the accuracy of the CG equation and corresponding drug dosing regimens have been questioned. Currently, no prospective pharmacokinetic studies have been conducted with use of the MDRD equation to generate dosing recommendations, and limited data are available to support its use in some patient populations representing demographic extremes. Collectively, these issues have resulted in considerable confusion among clinicians and have fueled a healthy debate on whether or not to use the MDRD equation to determine drug dosages. Each of these issues is reviewed, and a proposed algorithm for using creatinine-based kidney function assessments in drug dosing is provided. Knowledge of the advantages, limitations, and clinical role of each equation will facilitate their safe and effective use in drug dosing.

Use of estimated glomerular filtration rate for drug dosing in the chronic kidney disease patient

PURPOSE OF REVIEW

Assessment of kidney function is necessary to stage chronic kidney disease (CKD) and appropriately dose medications. The Cockcroft-Gault equation provides an estimate of creatinine clearance (eClCr) and is the method commonly referenced in pharmacokinetic studies. The Modification of Diet in Renal Disease (MDRD) and CKD-Epidemiology Collaboration (EPI) equations provide an estimate of glomerular filtration rate (eGFR), with the MDRD eGFR now automatically reported by most clinical laboratories. This review describes the differences in the Cockcroft-Gault, MDRD, and CKD-EPI equations and considerations when applying estimates from these equations for drug dosing.

RECENT FINDINGS

Studies evaluating drug-dosing regimens using eClCr and eGFR differ in their results depending on the population in which the equation is applied, the adjustment factors used to account for body size, and the number of dosing levels for a particular medication. The largest study to evaluate drug regimen design by method concluded that either the eGFR or Cockcroft-Gault estimates could be used for drug dosing. Differences in methodology among studies are a key factor in evaluating these results and will be highlighted in this review.

SUMMARY

The Cockcroft-Gault, MDRD, and CKD-EPI equations provide reasonable estimates of kidney function; however, clinicians must understand the limitations when using these estimates for drug regimen design.