How much is too much?

Ascites is the most common complication of portal hypertension associated with cirrhosis. The development of ascites is a harbinger of a poor prognosis and impaired quality of life. The mortality rate is approximately 50% 2 years after the development of ascites. Independent factors associated with ascites-related mortality include hyponatremia, increased serum creatinine levels, low arterial pressure, and low urine sodium levels. Among these variables, only the serum creatinine level is part of the formulation of the Model for End-Stage Liver Disease (MELD), which predicts 90-day mortality for patients awaiting liver transplantation. Therefore, the development of a risk prediction model to further improve risk profiling, especially for patients on the transplant waiting list, remains a top priority. Unfortunately, ascites is a subjective clinical marker that is difficult (if not impossible) to incorporate into defined, objective survival models. Heuman et al. previously demonstrated that hyponatremia and persistent ascites are MELD-independent predictors of early mortality and are especially important in patients with MELD scores lower than 21. In the field of liver transplantation, the greatest challenge continues to be the shortage of donor organs. The landscape has morphed and now includes the risk of using extended criteria donors because this might be the only opportunity or chance for patients. Therefore, developing an accurate, objective survival model that is fair and totally inclusive in association with donor allocation may be as difficult as total health care reform! In this issue of Liver Transplantation, Somsouk et al. address the daunting question of ascites and mortality risk while patients wait for liver transplantation. Using the Organ Procurement and Transplantation Network database, Somsouk et al. examined all new registrations for liver transplantation from 2005 to 2007 with follow-up to 90 days. Patients who were removed from the waiting list and died later were also considered to have died while they were waiting. Ascites was entered into the database by transplant coordinators at their centers at the time of registration and was classified as none, small, or moderate; 57% were noted to have small ascites, and 25% were noted to have moderate ascites. The study group consisted of 18,124 patients, and 1498 (8.3%) died. The mortality rate was greater in patients with moderate ascites versus those with no or small ascites (15.4% versus 4.1% and 15.4% versus 6.6%, respectively). With adjustments for the MELD score, the risk of death was doubled for patients with moderate ascites. Furthermore, in comparison with MELD and Model for End-Stage Liver Disease plus serum sodium (MELD-Na) scores, moderate ascites offered additional risk discrimination for predicting 90-day mortality. Somsouk et al. found that the mortality rate was higher in patients with moderate ascites, and the effect was more prominent with MELD scores lower than 21 (equal to 4.7 MELD units) and with MELD-Na scores lower than 21 (equal to 3.5 MELD-Na units). Lastly, the risk of death in high-demand US allocation regions for patients with MELD scores lower than 21 and moderate ascites was 8% higher than the risk in lower demand regions. There are several key points to this article. These data confirm previous studies reporting that moderate ascites is an independent risk factor associated with death, especially in patients with low MELD scores. Moreover, the authors quantify what this risk is with respect to risk-adjusted MELD scores. Lastly, patients with moderate ascites in high-demand regions have higher wait-list mortality.