@RISK Crucial in Live Donor Kidney Transplant Study
Living donor kidney transplantation is the preferred treatment for advanced renal failure. Roughly 20-25% of living donors can have asymmetry between their kidneys’ size and efficiency in filtration abilities. With a 10% or greater size difference between the two kidneys, doctors typically perform an additional test to measure the function of each kidney as a guide to select which kidney to transplant (they use the smaller, less efficient kidney for transplantation). Most transplant centers arbitrarily consider size and functional asymmetry of less than 10% as clinically insignificant, and asymmetry of more than 20% as a cut-off for transplantation, the concern being that the smaller kidney may not be healthy enough to be desirable for donation.
Dr. Bekir Tanriover, Assistant Professor of Internal Medicine at University of Texas Southwestern Medical Center, wanted to examine kidney transplant asymmetry more closely. “When you have more than a 10% difference in kidney size, how does this asymmetry translate into how well the kidney functions once it is transplanted in the recipient? How much kidney asymmetry is actually acceptable?”
To tackle these questions, Tanriover and his colleagues conducted a retrospective study of 100 kidney donors who had asymmetric kidneys, gathering three measurements from each patient: the kidney size (volume), filtration efficiency, and biopsy scores, and plugged them into @RISK.
Figure 1: A shows a scatter plot of kidney size (i.e., ‘Donated Volume’) versus the recipient’s outcome (measured as estimated glomerular filtration rate after 1 year). B shows split renal function test results versus patient outcome. Graph A shows a clearly defined positive correlation between kidney size and patient outcome.
The model showed a clear correlation between donor kidney size and recipient outcomes. In fact, the model showed that kidney size was the only variable that truly mattered when it came to the three measurements, negating the need for any more invasive testing on the donor kidneys.
Dr. Tanriover also conducted a sensitivity analysis in @RISK to determine if it is safe to transplant a kidney that has extreme functional asymmetry, or if the patient should wait for a kidney from a deceased donor. “The risk of receiving a preemptive living renal transplant with any extreme [functional difference], as long as adequate donor kidney volume is transplanted, outweighs the benefit of waiting for a deceased donor renal transplant with higher function,” Tanriover writes in the study, which appears in an upcoming issue of Transplantation. “The reason for this is that the preemptive kidney transplantation offers lower mortality and allograft failure risk as compared with patients who received a transplant while on dialysis.”
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Play Ball! Palisade Software Used in Award-Winning Sports Analytics Research
Baseball fans, take note: next time you're looking to place a bet on a game, you may want to use @RISK. That's what DePaul University professor Clayton Graham did to create his baseball wagering model, presented at the prestigious ninth annual 2015 MIT Sloan Sports Analytics Conference. Dr. Graham's research submission, “Diamonds on the Line: Profits through Investment Gaming,” topped the “Business of Sports” track and earned third place overall.
In the paper, Dr. Graham discusses how he uses Palisade’s DecisionTools Suite to create a baseball investment model to calculate the probability of winning individual games and the economic consequences of each wager based against each game’s betting line. Additionally, the research sought to determine the optimal bet size, based upon the risk tolerances of the investor.
“Palisade’s DecisionTools Suite was invaluable to the success of this lengthy project, as it quickly and easily computed the myriad statistical scenarios,” said Dr. Graham. “Baseball has a seemingly infinite set of possibilities with each at-bat, and the intricacies of determining what may happen would be impossible to determine manually, with any degree of expediency. DecisionTools Suite is also very easy to use and intuitive because it operates in Microsoft Excel. I can say, without hesitation, that this project would not have been possible without DecisionTools Suite and the technical support Palisade offers.”
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» Read the full paper
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