Fig. 4

The Kaplan–Meier survival curves of the terminal nodes identified by the survival tree analysis. The numbers on the plots display the nodes number. The black solid line shows survival curve of total population, and other lines show the survival curve of each terminal node. a Kaplan–Meier survival of 12 nodes of the survival tree of Fig. 3 for male population. It can be seen that the curves of nodes 4, 5, 7, 8, 22 and 23 are lower than the whole population’s curve, showing that they cover high risk groups for the CKD events. The symmetric remark can be made for nodes (11, 15, 16, 17, 18 and 20) which have a survival probability above the whole population’s curve which cover low risk groups for the CKD events among men. b Kaplan–Meier survival of 10 nodes of the survival tree of Fig. 5 for female population. The survival curves of nodes 16, 4, 19, 15, and 7 are lower than the whole population’s curve, and survival curves of nodes 12, 11, 6, and 9 have a survival probability above the whole population’s curve, showing the high risk and low risk groups for the CKD events among women, respectively