KDOQI AKI Commentary: necessarium lectionem

Bravo KDOQI panelists Paul Pavlesky and colleagues - they have taken a measured, balanced, and practical approach towards AKI. The commentary in AJKD is a must read (necessarium lectionem).

The commentary is available open-access on this link. Some highlights...

1. KDIGO definition or staging of AKI. 
"There is insufficient validation of this definition and staging system for its use in the diagnosis and clinical management of patients. In particular, we do not believe that there are sufficient data to support use of the stage-based management approach proposed in the KDIGO guideline."
They state: "Rather, management of patients with AKI should be based on assessment of overall clinical status, including specific cause of AKI, trends in kidney function over time, comorbid conditions, assessment of volume status, and concomitant acid-base and electrolyte disturbances."

2. The creation of a new category of AKI patients - patients with "Acute Kidney Disease" (AKD)
"The KDIGO guideline introduces the new term acute kidney disease (AKD), defined as AKI, or GFR <60 m="" min="" ml="" span="">² for less than 3 months, or a decrease in GFR by ≥35% or an increase in serum creatinine level by >50% for less than 3 months, or structural kidney damage of less than 3 months' duration....we have concern that the introduction of this terminology may confuse clinicians and inappropriately divert attention away from diagnostic considerations. 

The KDOQI panel also had problems with a lumper approach: "To lump the broad range of conditions that result in acute and subacute kidney disease, ranging from acute tubular necrosis to obstructive uropathy, atheroembolic disease, and rapidly progressive glomerulonephritis, into the single umbrella term of AKD runs the risk of promoting diagnostic laziness among clinicians who would have a convenient name to apply rather than an abnormal laboratory value to investigate." 

3. Management of AKI patients according to the stage of AKI. 
"We are especially concerned that the development of clinical action plans based on AKI stage may result in inappropriate protocolization of care. While recommendations such as discontinuation of nephrotoxic agents when possible and ensuring volume status and perfusion pressure in high-risk patients or patients with AKI, waiting until stage 2 AKI to check for changes in drug dosing implies that this need not be done earlier, while the recommendations for considering initiation of RRT and intensive care unit admission in stage 2 AKI seem premature. Overall, we thought that the extreme heterogeneity of AKI and its lack of consistent mapping to stages 1, 2, and 3 make the proposed stage-based management of AKI clinically unhelpful and inapplicable to many patients."

4.  Follow-up of patients after an episode of AKI
KDOQI agreed with  "close postdischarge clinical evaluation of patients with moderate to severe AKI". They also agree that patients with stage 3 AKI and other high risk patients should be followed up (e.g., patients with AKI in the setting of pre-existing CKD or those who develop worsening CKD as a consequence of an episode of AKI). They do not recommend that patients with either mild AKI or those at low risk of progressive kidney disease be followed post-discharge.

An unusual virus transmitted by a transplanted kidney

source: www.dmvfollowers.com

There are many viruses that can be transmitted by a kidney. Rabies would not be anywhere near the top of my list. However, the New York Times recently published a story about a Maryland patient who died from rabies contracted from a kidney transplant. 

According to the study: "Doctors did not know or even suspect that the organ donor had rabies, so he was not tested for the virus that causes it before his heart, liver and kidneys were removed for transplantation."

From a Washington Post article: "Transmission of rabies through organ or tissue transplant is extremely rare. Four people in Texas died in 2004 from rabies contracted from a single donor’s tissue. There have been at least eight cases around the world contracted through cornea transplants." 

An article in Medscape is worth a read on donor transmitted viral disease.

Central Body Fat and Kidney Disease

source: commons.wikimedia.org

It has been shown that obesity is associated with worsening kidney function in terms of renal hyperfiltration, hyperperfusion, as well as microalbuminuria. Central obesity (also known as central body fat) is well known as a risk factor for insulin resistance and type 2 diabetes. Several reports have associated central body fat with lower cardiopulmonary function and overall physical fitness. However, the deleterious effect of central body fat on renal function has been primarily attributed to other existing co-morbidities (e.g. diabetes, hypertention and hypercholesterolemia).

On April 11, 2013, Kwakernaaket al published a paper in the Journal of American Soceity of Nephrology(JASN) on whether body fat distribution, as measured by the waist/hip ratio (WHR), is associated with renal hemodynamics, independent of BMI, in a cross-sectional analysis of 315 healthy normotensive persons with normal fasting glucose levels.

The main finding of this study is that in the healthy population, independent from BMI, higher WHR was inversely associated with glomerular filtration rate and effective renal plasma flow, and positively associated with filtration fraction. These findings were consistent in both univariate and multivariate analyses.

The study was a cross-sectional analysis and thus no causal inference can be drawn. Additionally, WHR is not an accurate measure of central body fat, which involves several types of visceral fat. Rather, central body fat is best quantified by advanced imaging modalities e.g. DEXA, CT or MRI.

Nevertheless, the findings from this study support conclusions the PREVEND study that was published in the American Journal of Kidney Disease in 2003, also from the Netherlands. PREVEND provided evidence to support  central body fat as a a risk factor for diminished kidney function. 

The bottom-line is that increasing evidence now supports the conclusion that weight loss and increased physical activity are renoprotective even among healthy individuals.  

Dr. Youssef MK Farag 

Dr. Farag is a research fellow in the renal division at Brigham and Women’s Hospital, a teaching affiliate of Harvard Medical School. He is currently pursuing a master in public health in Johns Hopkins Bloomberg School of Public Health. His Harvard Catalyst profile is available here