Fig. 2

Plots of time-varying effects and cumulative covariate effects for medication use. Note: (A) The red line in Fig. 2(a) was the local linear estimation of fitted time-varying effects by VCSGF. The plots of time-varying effects showed that the local linear estimates were well fitted. (B) Fig. 2(b) showed the use of GCs at an early stage could be protective against the admission of patients with recurrent symptoms, which was indicated by the early cumulative covariate effect below the x-axis. However, this protective effect diminished with time and was reflected on the graph as the cumulative effect also moving closer to the x-axis