Glomerular filtration rate equations for liver-kidney transplantation in patients with cirrhosis: Validation of current recommendations

Abstract

Simultaneous liver and kidney transplantation (SLKT) remains the procedure of choice for patients with both endstage liver disease and kidney failure. Stringent guidelines are needed to avoid unnecessary kidney transplantation. A recent consensus meeting proposed criteria based on the Modified Diet in Renal Disease (MDRD)‐6 equation to estimate glomerular filtration rate (GFR). The aims of this study were to compare GFR equations to true GFR in candidates for liver transplantation (LT) and to determine the impact of inaccuracies on the current guidelines for SLKT. Three hundred stable cirrhosis patients evaluated for LT were studied. All patients had iohexol clearance to measure GFR at evaluation under stable conditions. Measured GFR (mGFR) was compared to MDRD‐4, MDRD‐6, and Chronic Kidney Disease Epidemiology Collaboration (CKD‐EPI) equations. MDRD‐6 was the most accurate equation to predict GFR. In the 290 patients with mGFR >30 mL/min/1.73 m2, 15 patients (7%) had estimated GFR (eGFR) ≤40 mL/min/1.73 m2 based on the MDRD‐6 equation, defining “discordant” patients. Among them, two underwent SLKT and 13 underwent LT alone. None of those who survived more than 1 year after LT alone (n = 8) developed renal dysfunction thereafter. In multivariate analysis, discordant patients were older (P = 0.03) and had lower sodium level (P = 0.02). Conclusion: The MDRD‐6 equation was superior to other equations at identifying cirrhosis patients with true GFR <30 mL/min/1.73 m2. However, the MDRD‐6 equation also tended to underestimate renal function in a subgroup of patients with true GFR >30 mL/min/1.73 m2, with a potential risk of unnecessary kidney transplantation if applying current U.S. recommendations for SLKT. (Hepatology 2014;59:1514‐1521)

Estimated Glomerular Filtration Rate in Renal Transplantation

“…There is an extensive literature that evaluates the performance of formulas. Several authors have questioned the reliability of these equations in diverse populations, such as type 2 diabetes mellitus, 3,4 CKD, 5,6 heart failure, 7,8 cancer patients, 9,10 liver transplantation, 11 cirrhosis, 12,13 or kidney transplantation. [14][15][16] In renal transplantation, Gaspari et al 17 evaluated 14 creatinine-based formulas and showed their poor performance in reflecting true GFR.…”

“…[19][20][21][22] Most of the studies used only an arbitrary percentage of error that includes the majority of the estimations. In general, it is considered acceptable to observe the estimations within bounds of error of ± 30% compared with the gold standard, [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] which is a wide limit of error.…”

Acute Kidney Injury in Cirrhosis

“…22,24 Among creatinine-based equations, it has been shown that MDRD-6 is the most accurate in cirrhosis. 25 However, in contrast to MDRD-4, MDRD-6 may underestimate true GFR, discordances being more pronounced in old patients and patients with low serum sodium. Other indirect markers of renal function such as cystatin C are available; however, they are costly and not widely available, and recent studies have shown that similar to sCr, cystatin C level is affected by muscle mass and liver disease and overestimates renal function in patients with cirrhosis.…”

“…25,68 Although duration of RRT (4-8 weeks) and GFR have been traditionally used by some centers to determine the need for simultaneous liver kidney (SLK) transplants, evidence-based guidelines for SLK are lacking. 40 Further investigations, particularly focusing on novel renal plasma protein biomarkers may provide further information on prognostication of potential post-LT renal recovery (along with cause of AKI) before making a decision to proceed with SLK transplant.…”

Renal dysfunction in patients with cirrhosis: Where do we stand?

“…According to KDOQI [51] , CKD is defined as a GFR of less than 60 mL/min for more than three months, calculated using the modified diet in renal disease (MDRD)-6 formula (Appendix 4) supporting its potential usefulness in the decision making for simultaneous liver and kidney transplantation. This hypothesis has been tested in patients with stable cirrhosis in the study of Francoz et al [52] . They showed that MDRD-6 formula was superior to MDRD-4 and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formulas identifying stable cirrhotic patients with markedly impaired renal function, including those with ascites (Table 3).…”