Prognosis of acute-on-chronic liver failure patients treated with artificial liver support system

Table 3 Calculation of probability of survival according to the risk score

Days	30	60	90	120	180	270
S0 (t)	92.50%	84.90%	79.70%	77.40%	71.80%	65.60%

S0(t) gives the estimated survival probabilities for a patient with a risk score of 3.7 which is the mean risk score of acute-on-chronic liver failure patients in the derivation cohort. To calculate the probability of survival at t days of a given patient use the following equation: S(t) = S0(t)^{exp(score-3.7)}.