Diffusion of a new drug among ambulatory physicians—The impact of patient pathways

When drugs enter the market, physicians' prescribing behavior plays a crucial role in the diffusion process. Although regulations to foster economically efficient prescribing exist, physicians have some degree of freedom in choosing medication and are subject to various influencing factors. The aim of the present analysis is to investigate how interaction among patients and physicians affects the diffusion. We look at two different ways that patient pathways might influence physicians and examine these effects for Sacubitril/Valsartan (S/V), a new drug for patients with heart failure. Using administrative data from Germany, we identify physicians who prescribed S/V in the first 2 years of its availability. We apply survival models to estimate the impact of the patient-physician interaction on the physicians' adoption time. To this end, we determine whether individual physicians treated patients that had been prescribed S/V, and how many other physicians already prescribing S/V were connected in patient-sharing networks. Our main findings are that patients with a previous prescription seem to induce adoption by demanding repeat prescriptions. Moreover, patients establish connections between physicians that may lead to prescriptions for new patients. Our results therefore suggest that patient pathways play a significant role in the diffusion of a new drug.