Influence of peer networks on physician adoption of new drugs

Abstract

Although physicians learn about new medical technologies from their peers, the magnitude and source of peer influence is unknown. We estimate the effect of peer adoption of three first-in-class medications (dabigatran, sitigliptin, and aliskiren) on physicians’ own adoption of those medications. We included 11,958 physicians in Pennsylvania prescribing anticoagulant, antidiabetic, and antihypertensive medications. We constructed 4 types of peer networks based on shared Medicare and Medicaid patients, medical group affiliation, hospital affiliation, and medical school/residency training. Instrumental variables analysis was used to estimate the causal effect of peer adoption (fraction of peers in each network adopting the new drug) on physician adoption (prescribing at least the median number prescriptions within 15 months of the new drug’s introduction). We illustrate how physician network position can inform targeting of interventions to physicians by computing a social multiplier. Dabigatran was adopted by 25.2%, sitagliptin by 24.5% and aliskiren by 8.3% of physicians. A 10-percentage point increase in peer adoption in the patient-sharing network led to a 5.90% (SE = 1.50%, p<0.001) increase in physician adoption of dabigatran, 8.32% (SE = 1.51%, p<0.001) increase in sitagliptin, and 7.84% increase in aliskiren adoption (SE = 2.93%, p<0.001). Peer effects through shared hospital affiliation were positive but not significant, and medical group and training network effects were not reliably estimated. Physicians in the top decile of patient-sharing network peers were estimated to have nearly 2-fold stronger influence on their peers’ adoption compared to physicians in the top decile of prescribing volume. Limitations include lack of detailed clinical information and pharmaceutical promotion, variables which may influence physician adoption but which are unlikely to bias our peer effect estimates. Peer adoption, especially by those with whom physicians share patients, strongly influenced physician adoption of new drugs. Our study shows the potential for using information on physician peer networks to improve technology diffusion.

Promoting rational antibiotic prescribing for non-complicated infections: understanding social influence in primary care networks in Germany

“…If these fail to be considered adequately, social influence processes and potentially present opinion leadership are likely to be overestimated [26]. It is known that physicians influence each other, but the magnitude of peer influence is still poorly understood [27]. In this study however, participants attached general importance to social learning and the social support offered by their PCNs: Peer exchange was strongly emphasized as a major asset while there was hardly any mention of individual local opinion leaders.…”

Association of Physician Peer Influence With Subsequent Physician Adoption and Use of Bevacizumab

“…We identified 34 750 patients ( [21] physicians per community [range, ). Characteristics of the patients are included in Table 1.…”

“…In a related analysis, 20 they also found that direct connection with early adopters of magnetic resonance imaging was associated with greater surgeon use of this technology, and the strength of the association attenuated as the degree of separation between the 2 physicians increased. Another recent study 21 underscored the role of physician peers on adoption of 3 first-inclass oral medications (dabigaltran, sitagliptin, and aliskiren), finding that the use of these drugs by peers as measured by patient-sharing networks was more important than prescribing by peers within the hospitals or medical groups where they practiced. This may suggest that exposure to these new drugs prescribed by another physician increases knowledge about the drugs and comfort prescribing them.…”

“…For example, academic detailing has potential to influence clinician behavior, especially if targeted to key opinion leaders who are perceived as influential experts by their peers. 21,27 Other evidence suggests that in decentralized networks, social influence can generate learning dynamics that improve the performance of the group, 28 which could potentially slow adoption of low-value therapies or those lacking sufficient evidence.…”

Promoting rational antibiotics prescribing for non-complicated infections: Understanding social influence in primary care networks in Germany

“…If these fail to be considered adequately, social influence processes and potentially present opinion leadership are likely to be overestimated [26]. It is known that physicians influence each other, but the magnitude of peer influence is still poorly understood [27]. In this study however, participants attached general importance to social learning and the social support offered by their PCN: Peer exchange was strongly emphasized as a major asset while there was hardly any mention of individual local opinion leaders.…”