Performance of Methods to Assess Kidney Function in a Predominantly Overweight Sample of Patients with Liver Disease

Abstract

The assessment of glomerular filtration rate (GFR) in patients with liver disease is necessary to make decisions about organ allocation. Creatinine is widely used as a marker of GFR; however, it is not reliable in patients with liver disease. The aims of this study were to (1) determine if iodine 125-labeled iothalamate ( 125 I-iothalamate) clearance calculated using the plasma decay method is equal to renal clearance of 125 I-iothalamate and (2) estimate kidney function using the creatininebased Cockcroft-Gault and the Modification of Diet in Renal Disease equations, a cystatin C-based equation, the urine collection method for creatinine clearance, and plasma clearance of vancomycin (V) and compare these estimates to renal clearance of 125 I-iothalamate in adult patients with liver disease. Adults with liver disease received 125 I-iothalamate and V and had a catheter placed for urine collection. Blood and urine samples were collected over 8 h for analysis of 125 I-iothalamate, creatinine, and V to determine kidney function. Estimates were compared to renal 125 I-iothalamate clearance. Eight patients classified as Child-Pugh class B were enrolled: age was 52 AE 6 years; body mass index was 36.5 AE 19 kg/m 2 ; and Model for End-Stage Liver Disease score was 13 AE 3. Mean estimates of kidney function did not differ significantly from mean renal 125 I-iothalamate clearance (74 AE 38 mL/min/1.73 m 2 ). Other methods overestimated kidney function at lower levels of GFR (<60 mL/min/1.73 m 2 ) and underestimated kidney function at higher GFR levels. Given the variability in performance of methods to assess kidney function in this population, direct measurement of GFR may be preferable to indirect estimates based on marker compounds such as creatinine and cystatin C until more accurate methods are developed.

Estimating Glomerular Filtration Rate in Cirrhosis Using Creatinine‐Based and Cystatin C–Based Equations: Systematic Review and Meta‐Analysis

“…1). ( 9,11,13‐15,27‐46 ) These were based on sCr (MDRD, MDRD 4 variables [MDRD 4], MDRD 5 variables [MDRD 5], MDRD 6, CG, creatinine clearance [CrCl]‐MDRD [CM], Nank, GRAIL, RFH, CES, and CrCl), serum CysC (chronic kidney disease–Epi–CysC [CEC], Hoek, and Larsson), or both (Mindikoglu, chronic kidney disease–Epi–sCr–CysC [CESC], Stevens, China Cr‐CysC; Supporting Table 4).…”

“…1). (9,11,(13)(14)(15)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42)(43)(44)(45)(46) These were based on sCr (MDRD, MDRD 4…”