Assessment of Prognosis of Cirrhosis

François Durand, M.D.; Dominique Valla, M.D.

Disclosures

Semin Liver Dis. 2008;28(1):110-122. 

In This Article

Child's Score

Child's score, initially termed Child-Turcotte score, was proposed more than 30 years ago.[3] It was originally designed for predicting the outcome after surgery for portal hypertension (portocaval shunting and trans-section of the esophagus) in patients with cirrhosis. Child-Turcotte score included two continuous variables (bilirubin and albumin) and three discrete variables (ascites, encephalopathy, and nutritional status) which were empirically selected because they were felt to have their own influence on the prognosis in this context.[4]

A modified version termed Child-Pugh score was proposed ∼20 years ago ( Table 2 ).[5] The only change in this modified version was that nutritional status was replaced by prothrombin time. Initially, prothrombin time was expressed in seconds. However, a limitation comes from the fact that prothrombin can also be expressed as either a percentage of normal (prothrombin index) or as international normalized ratio (INR), this latter being now the reference in many countries. The original cut-off values of 4 and 6 seconds for prothrombin time prolongation correspond approximately to a prothrombin index of 50% and 40%, respectively. These same values roughly correspond to an INR of 1.7 and 2, respectively. Child-Pugh score corresponds to the total of points for each item. According to the sum of these points, patients can be categorized into Child-Pugh grades A (5 to 6 points), B (7 to 9 points), or C (10 to 15 points). The variables included in Child-Pugh score are not specific markers of the synthesis (albumin and prothrombin) and elimination (bilirubin) functions of the liver. Indeed, changes in serum albumin may be also related to increased vascular permeability,[6] especially in cases of sepsis, and large-volume ascites.[7] Similarly, bilirubin can be increased as a consequence of impaired renal function, hemolysis, or sepsis.[8] Prolonged prothrombin time can be a consequence of an intravascular activation of coagulation during sepsis.[9] Overall, the individual components of the Child-Pugh score encompass a broader spectrum of conditions than the single impairment of “liver function.” Child-Pugh score as a whole is also a marker of the multiorgan changes resulting from cirrhosis.

Several studies have shown that Child-Pugh score is an independent prognostic marker in the settings of ascites,[10] ruptured esophageal varices,[11] alcoholic cirrhosis,[12] hepatitis C virus- (HCV-) related cirrhosis,[13] primary biliary cirrhosis (PBC),[14] primary sclerosing cholangitis (PSC),[15] and Budd-Chiari syndrome.[16] Child-Pugh score, which can be easily calculated at the bedside, has been widely used for selecting candidates for resection of HCC[17] and nonhepatic surgery.[18]

Attempts have been made to improve the accuracy of Child-Pugh score by incorporating other markers of liver function (such as the clearance of galactose, indocyanine green, aminopyrine, and lidocaine).[19,20,21,22] However, these additional markers had a limited value. The incorporation of conventional markers of nutritional status to Child-Pughscore also had a limited value.[23]

Since the five variables of Child-Pugh score were selected empirically, it can be anticipated that not all are independent predictors of prognosis. For example, albumin and prothrombin time are somewhat redundant. Including both variables in a single score may result in overweighting their own influence.

The cut-off value for each variable has been empirically selected. There is no evidence that moving from one class to the next one translates into a proportional change in mortality risk. As an example, patients with serum bilirubin above 100 μmol/L may be under-scored with Child-Pugh, because the limit for the upper class of bilirubin is only 51 mmol/L. This ceiling effect of discrete classes does not exist with continuous variables. In addition, the limits for qualitative variables (ascites and encephalopathy) are still vague. They may be influenced by subjective interpretation.

The five variables of Child-Pugh score are empirically given the same weight, which is also questionable. Multivariate analysis has shown that the proper weight of predictive factors is quite variable. For example, the weight of INR is three times as high as that of bilirubin in MELD score.[24]

Child-Pugh score does not take into account specific variables, serum creatinine in particular, which have been shown to have a determinant impact on the prognosis of cirrhosis.[10,24] Similarly, it has been shown that the addition of markers of portal hypertension, such as esophageal varices, portal blood velocity, and hepatic venous pressure gradient (HVPG), would improve the accuracy of Child-Pugh score.[20,25,26]

Finally, Child-Pugh score does not take into account the cause of cirrhosis and the possibility of stopping (or slowing) the damaging process to the liver. This limitation is especially relevant in patients with alcoholic cirrhosis or with hepatitis B virus- (HBV-) related cirrhosis with viral replication.

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