Kinetic estimated glomerular filtration rate in critically ill patients: beyond the acute kidney injury severity classification system

Abstract

BackgroundAlthough significant advances have been achieved in acute kidney injury (AKI) research following its classification, potential pitfalls can be identified in clinical practice. The nonsteady-state (kinetic) estimated glomerular filtration rate (KeGFR) could add clinical and prognostic information in critically ill patients beyond the current AKI classification system.MethodsThis was a retrospective analysis using data from the Multiparameter Intelligent Monitoring in Intensive Care II project. The KeGFR was calculated during the first 7 days of intensive care unit (ICU) stay in 13,284 patients and was correlated with outcomes.ResultsIn general, there was not a good agreement between AKI severity and the worst achieved KeGFR. The stepwise reduction in the worst achieved KeGFR conferred an incremental risk of death, rising from 7.0% (KeGFR > 70 ml/min/1.73 m2) to 27.8% (KeGFR < 30 ml/min/1.73 m2). This stepwise increment in mortality remained in each AKI severity stage. For example, patients with AKI stage 3 who maintained KeGFR had a mortality rate of 16.5%, close to those patients with KeGFR < 30 ml/min/1.73 m2 but no AKI; otherwise, mortality increased to 40% when both AKI stage 3 and KeGFR < 30 ml/min/1.73 m2 were present. In relation to another outcome—renal replacement therapy (RRT)—patients with the worst achieved KeGFR < 30 ml/min/1.73 m2 and KDIGO stage 1/2 had a rate of RRT of less than 10%. However, this rate was 44% when both AKI stage 3 and a worst KeGFR < 30 ml/min/1.73 m2 were observed. This interaction between AKI and KeGFR was also present when looking at long-term survival.ConclusionBoth the AKI classification system and KeGFR are complementary to each other. Assessing both AKI stage and KeGFR can help to identify patients at different risk levels in clinical practice.Electronic supplementary materialThe online version of this article (doi:10.1186/s13054-017-1873-0) contains supplementary material, which is available to authorized users.

Kinetic estimated glomerular filtration rate as a predictor of successful continuous renal replacement therapy discontinuation

“…Kinetic eGFR magnifies the change between the last sCr value and the present one, and can, therefore, overcome the delay in detection of kidney function changes seen with a single measurement of sCr or regular eGFR based on sCr at one time‐point. Kinetic eGFR is previously reported to be useful in the early prediction of delayed graft function (DGF) within 4 h of renal transplantation, prediction of short‐term renal recovery after AKI, and identifying risks for RRT requirement during ICU stay and hospital mortality . In this preliminary study, we introduced the possibility that kinetic eGFR can be used as a predictor for CRRT discontinuation in addition to the conventional parameters including urine volume.…”

“…Kinetic eGFR is previously reported to be useful in the early prediction of delayed graft function (DGF) within 4 h of renal transplantation, 19 prediction of short-term renal recovery after AKI, 20 and identifying risks for RRT requirement during ICU stay and hospital mortality. 21 In this preliminary study, we introduced the possibility that kinetic eGFR can be used as a predictor for CRRT discontinuation in addition to the conventional parameters including urine volume. We also proposed discontinuation index (DI) for clinical utility.…”

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

“…De Oliveira Marques et al [13] found that KeGFR did not correlate with AKI severity in their ICU cohort but the worst achieved KeGFR conferred an incremental risk of death in a stepwise manner. However, this study excluded patients with an initial MDRD GFR of < 30 mL/ min and/or a Cr of > 4 mg/dL.…”

“…The KeGFR equation has been applied in recent studies involving patients in ICU, post-operative patients, and renal transplant recipients [13][14][15][16]. The common characteristic of the study subjects in these patient cohorts is inhospital AKI with known renal injury onset time.…”

“…If height and weight are not available to the laboratory to calculate V D , it is possible to fix a maximum Cr change/day threshold based on age and gender [6,13]. However, if a fixed value is used, in subjects with large muscle mass the change in Cr (∆PCr in the numerator in expression 2) may exceed the max ∆Cr/day in the denominator resulting in a negative KeGFR.…”