Serum sodium, renal function, and survival of patients with end-stage liver disease

Background & Aims: Serum creatinine, a component of the model for end-stage liver disease (MELD), is an important prognostic indicator in patients with end-stage liver disease (ESLD). In addition, serum sodium has recently been recognized as an important predictor of mortality in patients with ESLD. We investigate the role of serum creatinine and sodium, and glomerular filtration rate (GFR) as determinants of survival in patients with ESLD. Methods: A prospective database was utilized to identify all adults listed for primary liver transplantation (LTx) at the Mayo Clinic, Rochester, between 1990 and 1999. GFR was measured by iothalamate clearance. Results: Among 837 patients listed for LTx, 660 had complete data including measured GFR. There was a significant association between GFR and survival after adjustment for MELD, with a linear rise in the risk of death as GFR decreased between 60 and 20 ml/min/1.73 m². Multivariable models showed that GFR is superior to creatinine in predicting mortality - a model consisting of total bilirubin (hazard ratio (HR) = 2.17, p < 0.01), INR (HR = 3.26, p < 0.01) and GFR (HR = 0.42, p < 0.01) was superior to MELD (chi-square 65.6 vs. 59.4, c-statistic 0.792 vs. 0.780). Serum sodium did not contribute to survival prediction when accurately measured GFR data were available. Conclusions: Serum concentrations of creatinine and sodium in patients with end-stage liver disease reflect a reduction in renal function, the underlying event that decreases survival.