Figure 4.

Time evolution of the dynamic path model containing PPARD and ADFP. This figure shows the time evolution of the model from model 2 of Figure 1. (a) The cumulative indirect effect of PPARD (through ADFP) on survival, and (b) the cumulative direct effect of PPARD on survival. The indirect and direct effects are estimated as explained in Materials and methods; see particularly equations 3 and 4 for details of the calculations. The indirect effect is approximately constant for the first six years, and zero thereafter (recall that the plots are cumulative). Similarly, the direct effect remains positive and stable for the first three years, and then becomes zero. As expected, confidence intervals become wider over time, due to fewer remaining patients. Based on these plots, the use of a five year horizon seems reasonable.