The clinical utility of kinetic glomerular filtration rate

Abstract

Background: In acutely unwell patients with rapidly changing renal function, estimating glomerular filtration rate (GFR) and predicting adverse renal outcomes are challenging and often inaccurate. Kinetic GFR (kGFR) is an estimate of immediate biomarker clearance derived from two discreet measurements that may better represent acute function. Our objective is to assess the clinical utility of kGFR as a predictive tool and examine the association of kGFR to adverse renal outcomes compared with measurements to traditional estimates. Methods: We compared the association of kGFR and Modification of Diet in Renal Disease (MDRD) with acute kidney injury (AKI), renal replacement therapy (RRT), cardiovascular morbidity, 30-day mortality and new chronic kidney disease development. A total of 107 acute admissions to a medical high dependency and intensive care unit were assessed retrospectively. Creatinine measurements and outcomes were recorded and kGFR was calculated at the earliest possible time point. This was then compared with simultaneous MDRD estimated GFR. Results: Mean age was 60 years old, AKI occurred in 25% of patients, acute cardiovascular events occurred in 13%, RRT was initiated in 15% and 30-day mortality was 30%. kGFR predicted the AKI more accurately than MDRD [area under the receiver operating characteristic curve (AUC) = 0.86 versus AUC = 0.64]. kGFR predicted the need for RRT more accurately than MDRD (AUC = 0.901 versus AUC = 0.79). Neither kGFR nor admission MDRD was associated with 30-day mortality or cardiovascular morbidity. Conclusions: Measuring kGFR in the acute setting could help clinicians better predict adverse renal outcomes.

Using the Kinetic Estimating Glomerular Filtration Rate Equation for Estimating Glomerular Filtration Rate and Detecting Acute Kidney Injury: A Pilot Study

“…On the contrary, the KeGFR timeline recognises the sluggish nature of the rise in serum creatinine on the second day due to the increase rather than decrease in Cr excretion as a result of the rising GFR (as Cr generation is unlikely to change in such a short time period and assuming V D is stable). This particular aspect of KeGFR may impact the need for RRT, as already shown [9]. The authors found that KeGFR associates better with the need for RRT when compared to MDRD GFR in a retrospective series.…”

“…Also, the spectre of validity of baseline Cr does not loom large in these patient groups as the initial Cr is the true baseline Cr. KeGFR has been used as a prognostic tool and compared with MDRD GFR for accuracy and prediction of renal recovery [9,14].…”

“…Sullivan and Doyle compared KeGFR to MDRD GFR and found that KeGFR better predicted the need for RRT (9). The investigators did not classify AKI based on KeG-FR, and AKI was diagnosed based on AKIN criteria.…”

Using Kinetic eGFR for Drug Dosing in AKI: Concordance between Kinetic eGFR, Cockroft-Gault Estimated Creatinine Clearance, and MDRD eGFR for Drug Dosing Categories in a Pilot Study Cohort

“…Among acute medical admissions to the high-dependency unit and intensive care unit, the AUC for AKI was 0.86 for KeGFR versus 0.64 for MDRD eGFR. The AUC for predicting the need for renal replacement therapy was 0.901 [2]. When KeGFR was used, the AUC for major adverse kidney events (MAKEs) was higher than that for novel biomarkers and Cr in another study in the intensive care unit setting from France [3].…”

“…The CG equation estimates Cr clearance rather than GFR and is not validated for use with IDMS-traceable Cr levels. The kinetic equation by Chen (KeGFR) estimates GFR for the nonsteady-state Cr level and is being validated in patient cohorts with acute kidney injury (AKI) [1][2][3][4][5]. In our pilot study, we were able to apply the KeGFR equation to detect AKI among acute medical admissions [6].…”