Performance of Creatinine-Based GFR Estimating Equations in Solid-Organ Transplant Recipients

Abstract

Background Accurate assessment of kidney function is important for management of solid organ transplant recipients. In other clinical populations, glomerular filtration rate (GFR) is most commonly estimated using the CKD-EPI (Chronic Kidney Disease–Epidemiology Collaboration) creatinine or the 4-variable MDRD (Modification of Diet in Renal Disease) Study equation. The accuracy of these equations compared to other GFR estimating equations in transplant recipients has not been carefully studied. Study Design Diagnostic test study. Setting & Participants Solid organ transplant recipients >6 months post-transplantation from 5 clinical populations [N=3,622, including recipients of kidney (53%), liver (35%) and other or multiple organs (12%)] Index Test Estimated GFR (eGFR) using creatinine-based GFR estimating equations identified from a systematic review of the literature. Performance of the CKD-EPI creatinine and MDRD Study equations was compared to alternative equations. Reference Test Measured GFR (mGFR) from urinary clearance of iothalamate or plasma clearance of iohexol. Measurements Error (difference between the mGFR and eGFR) expressed as P30 (proportion of absolute percent error <30%) and mean absolute error. Results We identified 26 GFR estimating equations. Mean mGFR was 55.1 ± 22.7 (SD) ml/min/1.73 m2. P30 and mean absolute error for the CKD-EPI and MDRD Study equations were 78.9% (99.6% CI, 76.9%–80.8%) for both and 10.6 (99.6% CI, 10.1–11.1) vs. 11.0 (99.6% CI, 10.5–11.5) ml/min/1.73 m2, respectively; these equations were more accurate than any of the alternative equations (p<0.001 for all pair-wise comparisons for both measures). They performed better than or as well as the alternative equations in most subgroups defined by demographic and clinical characteristics, including the type of transplanted organ. Limitations Study population included few non-whites and people with solid organ transplants other than liver and kidneys. Conclusions The CKD-EPI creatinine and MDRD Study equations perform better than the alternative creatinine-based estimating equations in solid organ transplant recipients. They can be used for clinical management.

Estimating glomerular filtration rate in kidney transplantation: Still searching for the best marker

“…They also concluded that there was no difference between these two equations in the overall study population, but CKD-EPI equation showed better performance at higher GFRs compared with better performance of MDRD Study equation at lower GFRs, which is in agreement with the results of the systematic review performed by Earley et al [58] . This study [57] may have implications in clinical practice, support the use of these eGFR equations to routine access renal function in transplant patients as in other populations. Even though it was a good diagnostic test study design with a standardized reference test, the study population included few nonwhites and individuals with solid organ transplants other than liver and kidneys;…”

“…The relative BIAS, hereafter named percent BIAS, is expressed as the proportion of true GFR represented by the absolute bias, and was calculated as: absolute BIAS/true GFR × 100. PRECISION expresses the therefore assessment of the equation performance in these subgroups is limited [57] . However we can't ignore that SCr levels are affected by factors besides GFR, and several studies suggest worse stage-based care in kidney transplant patients compared with native kidney diseases [59,60] , so any eGFR equations based on SCr still have limitations.…”

“…Other studies compare the performances of the MDRD and CKD-EPI equations in a large transplant patient's cohort [55,56] and the authors concluded that the latter equation does not offer a better GFR estimation in this population. More recently, Shaffi et al [57] , conducted a systematic evaluation of the development methods of all published Cr-based eGFR equations, and assess their performance in a large population (n = 3622) of solid-organ transplant recipients, including 53% kidney transplant recipients. They founded that the CKD-EPI [50] and IDMS-traceable 4-variable MDRD Study equations [48] were more accurate than the alternative equations, including those developed in populations including only transplant recipients, and as accurate as observed in non-transplanted populations.…”

Clinical Decision Making in a Patient with Stage 5 CKD—Is eGFR Good Enough?

“…Precise knowledge of GFR might be of value in patients, such as mine, who may have symptoms suggestive of uremia given that symptoms of uremia can be subtle and are nonspecific, medication dosing (or avoidance) (57)(58)(59), use of contrast media, assessing individuals considering living kidney donation (60)(61)(62) or who are transplant recipients (63), and planning timing of dialysis access or the start of dialysis and transplantation. Knowing the measured GFR might be important also when trying to assess kidney function in patients who are elderly (64), are morbidly obese, have significant nonrenal acute or chronic illness, have reduced muscle mass, have liver disease, have malnutrition, or had an amputation.…”

Enfermedad renal crónica en pacientes trasplantados de hígado en el Hospital Pablo Tobón Uribe 2005-2013

“…Como desenlace principal se evaluó la tasa de filtración glomerular (TFG) al momento del trasplante y durante el tiempo de seguimiento. La TFG fue calculada con la ecuación CKD-EPI (14).…”