Which is the holy grail in liver transplantation: Hyponatremia, MELD, or a combination?

We read with interest the paper by Ruf et al. published in a recent issue of Liver Transplantation.1 This study aimed to look at the predictive ability of the Model for End-Stage Liver Disease (MELD) with or without the addition of serum sodium level. The authors found that for patients with cirrhosis, MELD in combination with hyponatremia may further increase the predictive ability compared with MELD alone. Although their findings are generally consistent with those in a recent study which showed that serum sodium is an independent poor prognostic predictor in patients with advanced cirrhosis,2 a potential flaw of the study by Ruf et al.1 is that ascites has not been incorporated into the prognostic model to justify its usefulness. It is noteworthy that in the current study by Ruf et al.1 all of the 34 hyponatremic patients also had concomitant clinical ascites. Interestingly, of the 19 patients who died within 3 months of listing, 90% of patients had clinical ascites, compared with 63% who had hyponatremia. These results highly suggest that in addition to hyponatremia, ascites is also possibly a strong negative predictor. Failure to incorporate this important factor into the predictive model for comparison may compromise their results and conclusions. MELD, Model for End-Stage Liver Disease. MELD has become the prevailing criteria for organ allocation in liver transplantation. However, the MELD system may not serve all patients equally well and could have certain limitations.3 Another study suggested that inclusion of hepatic encephalopathy into the prognostic model may add additional prognostic value to the MELD score.4 Alternatively, ascites and hyponatremia were two important prognostic predictors, especially in patients with cirrhosis who had lower range MELD scores.5 In addition, MELD has a potential inherent limitation in that the occurrence of encephalopathy or ascites does not correlate well with the MELD score.6 These data indicate that patients with certain unfavorable predictors, such as ascites, hyponatremia, or encephalopathy, do not necessarily have a higher MELD score and the priority for transplantation could be downstaged in the MELD era. We agree that the MELD system is particularly useful as a tool to fairly allocate donor organs in a large patient population as a whole. Nevertheless, since patients awaiting transplantation are intrinsically heterogeneous and could have different clinical scenarios, an additional prognostic predictor that has powerful differentiation ability should be incorporated into the MELD model for further refinement. Teh-Ia Huo tihuo@vghtpe.gov.tw* , Shou-Dong Lee* , Jaw-Ching Wu* , * National Yang-Ming University School of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, Department of Medical Education and Research, Taipei Veterans General Hospital, Taipei, Taiwan.