“…Notably, this also poses challenges to the modeling of pharmacoeconomics of PD treatments in this early stage. Internationally, economic analyses of new drugs in PD models have often been designed using Markov models with explicit HY staging, focusing on delays in need for conventional PD treatments or dichotomizing patients over more or less than 25% time OFF during waking hours [14,[17][18][19][20][21][22][23][24][25]. From these publications, it appeared that using the specific Markov assumptions presented a valid approach towards modeling PD disease progression [26,27].…”