Estimating GFR in Adult Patients with Hematopoietic Cell Transplant

Abstract

Background and objectives Formal evaluation of kidney function before and after hematopoietic cell transplant is important to determine conditioning regimens, type of transplant, and medication dosing. Serum creatinine and estimating equations may not accurately assess kidney function.Design, study, participants, & measurements Existing estimating equations for GFR were compared with an iohexol measure of GFR in a prospective cohort study of 50 patients undergoing hematopoietic cell transplant and subsequent care at the Fred Hutchinson Cancer Research Institute from 2009 to 2013. Patients underwent iohexol GFR, serum creatinine, and cystatin C determination at baseline and day 100 posthematopoietic cell transplant. Iohexol GFR measurements were compared with the CKD Epidemiology Collaboration, Inker CKD Epidemiology Collaboration cystatin C with and without serum creatinine, Modification of Diet in Renal Disease, and Cockcroft-Gault estimating equations using Bland-Altman analysis and McNemar's test. The iohexol measurements were also compared with blood samples collected simultaneously on filter paper.Results Mean differences between iohexol GFR and eGFR on the basis of Bland-Altman analyses ranged from 220.6 to +15.4 ml/min per 1.73 m 2 at baseline and 212.7 to +12.9 ml/min per 1.73 m 2 at day 100. The CKD Epidemiology Collaboration and Modification of Diet in Renal Disease estimating equations classified 64% of patients with a GFR,90 at baseline compared with 38% by iohexol GFR (P=0.003 and P,0.01, respectively). No statistically significant differences were seen at day 100. The filter paper GFR had a mean difference of 0 at baseline and 5.9 at day 100. Additionally, 21%-37% and 57%-89% of eGFRs were within 10% and 30%, respectively, of the iohexol GFR at baseline, and 16%-34% and 72%-84% were within 10% and 30%, respectively, of the iohexol GFR at day 100; 98% of the filter paper estimates at baseline were within 30%, and 46% were within 10% of iohexol GFR.Conclusions The estimating equations are neither accurate nor precise in the hematopoietic cell transplant population, and clinical decision may require measurement of GFR.

Baseline Renal Function and Albumin are Powerful Predictors for Allogeneic Transplantation-Related Mortality

“…Given the important prognostic role of renal function and the need for dose adjustments accordingly, accurate evaluation of GFR is imperative in HSCT candidates. The accuracy of methods for measurement or estimation of renal function in HSCT patients may be influenced by fluctuations in nutritional status, muscle mass, and medications [31]. We have selected the CKD-EPI equation because it provides a more precise estimation of GFR compared with the Cockcroft-Gault equation, which is a direct measurement of creatinine.…”

Iohexol plasma clearance for measuring glomerular filtration rate in clinical practice and research: a review. Part 1: How to measure glomerular filtration rate with iohexol?

“…The high sensitivity also allowed the development of finger-prick samples (capillary sampling). However, this capillary technique needs to be developed further, as the precision of this method cannot yet be considered sufficient [ 60 – 65 ]. Measurement of iohexol by XRF has been well described [ 45 , 66 – 72 ] but requires specific instrumentation.…”

Ambulatory Blood Pressure and Endothelial Dysfunction in Hematopoietic Cell Transplantation Recipients

“…One limitation of this study is the small sample size. Estimating equations were used to assess eGFR, which are known to be imprecise in this patient population [31]. In addition, many of the patients in our study were treated with amlodipine for HTN, which is a known peripheral vasodilator and thus might have affected our results.…”