Diffusion of pharmaceuticals and the patient’s influence

Through what mechanisms are patients and physicians made aware of new pharmaceuticals and decide to prescribe them. It is well known that physician peer networks often help share information about new pharmaceuticals including clinical information as well as the providers own experience using the new treatment. Other studies have shown that direct to consumer advertising can cause patients to ask physicians about a drug. However, a study by Flemming et al. (2023) recognizes that there may be another information channel for physicians: the patients they treat who are already using a given drug.

patients with a previous prescription of a new drug could induce prescriptions by demanding a repeat prescription from a different physician. It has been shown that the adoption of a new drug accelerates when it is directly requested by patients (Liu & Gupta, 2012). This effect is an example of the “demand-induced supply” of medical services (Shih & Tai-Seale, 2011), which has been studied in the context of prescription drugs…

…. as patients…may choose which physicians to consult, they establish connections between physicians. Within the resulting patient-sharing networks, information transfer may take place.

The authors examine the extent to which this pathway operates using a case study of sacubitril/valsartan (S/V) among ambulatory physicians in Germany. The data used for the analysis was from 3 regional health care funds belonging to the AOK group of statutory health insurers. These data cover 4 German federal states (Bavaria, Hesse, Saxony, and Thuringia) between 2015-2017. The authors analyze the month of first prescription or initial prescription of S/V as the key outcome; the key explanatory variable was whether a physician treated a patient with a prescription for S/V the month before. The authors separately analyze patients who received the prescription from a physician in the same practice vs. a physician from another practice; this approach allows the authors to differentiate between the patient’s influence and possible peer effects within the practice.

….patients with prior prescription of a new drug induce its adoption by more physicians through repeat prescriptions. Additionally, we find evidence for a contagion effect within networks of physicians that are established through patient pathways. The effect is stronger when physicians do not strictly follow medical guidelines. The findings therefore suggest that patient pathways play a significant role in the diffusion of a new drug in ambulatory care.

An important finding. You can read the full paper here.