St. Mary├ó┬?┬?s Health Center, USA
Keynote: J Nephrol Ther
Background: Acute kidney injury (AKI) is a common and serious condition encountered in hospitalized patients. The severity
of kidney injury is defined by the RIFLE, AKIN and KDIGO criteria which attempts to establish the degree of renal impairment.
The KDIGO guidelines state that the creatinine clearance should be measured whenever possible in AKI and that the serum
creatinine concentration and creatinine clearance remain the best clinical indicators of renal function. Neither the RIFLE,
AKIN, nor KDIGO criteria estimate actual creatinine clearance. Furthermore, there are no accepted methods for accurately
estimating creatinine clearance in AKI.
Study Design: The present study describes a unique method for estimating K in AKI using urine creatinine excretion over
an established time interval (E), an estimate of creatinine production over the same time interval (P), and the estimated static
glomerular filtration rate (sGFR), at time zero, utilizing the CKD-EPI formula. Using these variables estimated creatinine
Setting & Participants: The method was tested for validity using simulated patients where actual creatinine clearance (Ka) was
compared to Ke in several patients, both male and female, and of various ages, body weights and degrees of renal impairment.
These measurements were made at several serum creatinine concentrations in an attempt to determine the accuracy of
this method in the non-steady state. In addition, E/P and Ke was calculated in hospitalized patients, with AKI, and seen
in nephrology consultation by the author. In these patients the accuracy of the method was determined by looking at the
following metrics; E/P>1, E/P<1, E=P in an attempt to predict progressive azotemia, recovering azotemia, or stabilization in
the level of azotemia respectively. In addition, it was determined whether Ke<10 ml/min agreed with Ka and whether patients
with AKI on renal replacement therapy could safely terminate dialysis if Ke was greater than 5 ml/min.
Outcomes & Results: In the simulated patients, there were 96 measurements in 6 different patients where Ka was compared
to Ke. The estimated proportion of Ke within 30% of Ka was 0.907 with 95% exact binomial proportion confidence limits.
The predictive accuracy of E/P in the study patients was also reported as a proportion and the associated 95% confidence
limits: 0.848 (0.800, 0.896) for E/P<1; 0.939 (0.904, 0.974) for E/P>1 and 0.907 (0.841, 0.973) for 0.9
John Mellas, MD, has been practicing nephrology for thirty years in St. Louis, Missouri. He is the Senior Partner in the largest nephrology practice in St. Louis. He is also Chairman of the Nephrology Division at St. Mary’s Health Center where he is actively involved in teaching internal medicine trainees. He has developed a method to measure creatinine clearance in acute kidney injury and has been using it in his practice for the last several years. A detailed description of the method was published in Mathematical Biosciences in March 2016, titled, “The Description of a Method to Accurately Measure Creatinine Clearance in Acute Kidney Injury”. His talk will describe the logic behind the derivation of the method with patient examples provided to illustrate its use in the evaluation of the patient with acute kidney injury.