Treatment effect in the trial
delays deterioration
Two different treatment effects were considered: one that is proportional to time:Since those in the control group arm have a mean change from baseline of For the steady decline trajectory, a treatment effect that is proportional to control group arm change would be the same as a treatment effect that is proportional to time. We therefore look at a different pattern of treatment effect that still has a steady decline trajectory in both groups: a treatment effect that delays deterioration (“delayed decline”). In the delayed decline scenario, the mean trajectory in the treated group shows no change for 1.25 units of time (2.5 units of time for scenarios with Parameters were chosen such that the expected treatment effect on the mean level at 5 years is -0.25 (to 2 decimal places) for all trajectories (-0.5 with The mean trajectories in the treated and control groups of the trial are shown in Fig. Plots of the mean trajectory in each treatment group of the trial for scenarios with residual error variance Scenarios with no treatment effect were also considered, in order to assess the Type I error.