The relative role of the Child-Pugh classification and the Mayo natural history model in the assessment of survival in patients with primary sclerosing cholangitis

The Child-Pugh classification is a simple, convenient prognostic measure in patients with liver cirrhosis. We investigated the relative role of the Ch ild-Pugh classification and the Mayo model in the assessment of survival in patients with primary sclerosing cholangitis (PSC). Of the 173 patients de scribed in the original Mayo PSC natural history model, 147 patients had su fficient information in the medical record to allow computation of the Chil d-Pugh score. We used our most recent modification of the Mayo model to com pute the risk score, based on patient's age, serum levels of bilirubin, alb umin, and aspartate aminotransferase and history of variceal bleeding. Usin g the risk score (R), patients were divided into the low- (R < 0), intermed iate- (0 less than or equal to R < 2), and high-risk (R greater than or equ al to 2) groups. Kaplan-Meier estimates and proportional hazards analysis w ere used to evaluate the two prognostic models. Although there was a statis tically significant correlation between the Child-Pugh and Mayo risk scores , two-thirds of the patients had a Child-Pugh score of 5 or 6 and a relativ ely wide range of risk scores (-1.1-4.3). The probability of survival for 7 years in patients in the low-, intermediate-, and high-risk groups was 92% , 74%, and 40% for Child-Pugh class A (n = 96) and 100%, 62%, and 28% for C hild-Pugh class B patients (n = 44), respectively. There were only a small number (n 7) of Child-Pugh class C patients. In our age-adjusted multivaria te analysis, each unit increase in the Mayo risk score was associated with a 2.5-fold increase in the risk of death (95% confidence interval: 1.8-3.4, P < .01), whereas Child-Pugh classification had no significant impact on s urvival (Child-Pugh B vs. A: risk ratio = 1.1 [95% confidence interval: 0.6 -2.0]; Child-Pugh C versus A: risk ratio = 0.6 [95% confidence interval: 0. 2-1.8]). In contrast to the Child-Pugh classification, which was developed for advanced liver cirrhosis, the Mayo model provides valid survival inform ation, particularly in patients early in the course of PSC.