New Risk Calculator Better Predicts Renal Outcomes After Liver Transplant

The Glomerular Filtration Rate (GFR) Assessment In Liver disease (GRAIL) better predicts kidney dysfunction at 1 year and 5 years after a liver transplant (LT) vs existing equations, according to a recent study. In the future, GRAIL may serve as an alternate equation for clinical decision making regarding LT vs simultaneous liver-kidney transplantation (SLKT) in patients with liver disease on a wait list.

Existing equations that estimate GFR, including the CKD-EPI creatinine equation, MDRD-4 GFR equation, and MDRD-6 GFR equation, have demonstrated low accuracy in LT patients with renal dysfunction, defined as a GFR of less than 30 ml/min. However, these equations are regularly used for decision making regarding LT vs SLKT for wait-list patients.

For their study, the researchers assessed the ability of the GRAIL equation to predict the need for a kidney after LT in 12,122 samples from wait-list patients over a period of 30 years. The equation had been developed using objective variables, including creatinine, blood urea nitrogen, age, gender, race, and albumin, in order to estimate GFR based on the time of measurement relative to LT and the severity of renal dysfunction.

Measured GFR before and after LT were used as reference points. A GRAIL-estimated eGFR below 30 ml/min in wait-list patients was assessed as a potential predictor of renal outcomes, including a measured GFR below 20 ml/min, chronic dialysis, and needing a kidney during the 5 years following LT.

The 2001-2015 Scientific Registry of Transplant Recipients (SRTR) (n = 68,217) was used to externally validate the predictive capacity of GRAIL for wait-list patients. The efficacy and predictive capacity of GRAIL at 1 year and 5 years post-LT was compared with that of CKD-EPI, MDRD-4, and MDRD-6.

Results indicated that an eGFR of less than 30 ml/min among wait-list patients was better predicted by GRAIL (38%) vs CKD-EPI (12%), MDRD-4 (12%), and MDRD-6 (21%). Furthermore, needing a kidney at 1 and 5 years post-LT was also better predicted by GRAIL (71% and 62%, respectively) vs CKD-EPI (37%, 26%), MDRD-4 (41%, 29%), and MDRD-6 (49%, 35%).

The researchers noted that the majority of these cases would not have been predicted by existing equations, with GRAIL identifying 28% more cases at 1 year post-LT and 36% more cases at 5 years post-LT than the MDRD-6.

“GRAIL eGFR [below 30 ml/min] on the WL predicts [kidney after liver transplant] better than current equations,” the researchers concluded. “GRAIL may serve as alternate equation developed in patients with liver disease to enable critical therapy decisions regarding SLKT versus LTA.”

—Christina Vogt

Reference:

Asrani SK, Jennings L, Nadim MK, Levitsky J, Trotter JF, Klintmalm G. A novel equation, GRAIL (GfR assessment in liver disease) on the waitlist predicts need for kidney after liver transplantation. Paper presented at: The AASLD Liver Meeting; October 20-24, 2017; Washington, DC. http://onlinelibrary.wiley.com/doi/10.1002/hep.29500/epdf.