Background: Candidates for specialty drugs, the fastest growing and costliest pharmaceuticals, typically originate with primary care referrals. However, little is known about what drives such referrals—especially for large populations such as short, otherwise normal children (idiopathic short stature). Recent expanded approval of growth hormone (GH) makes more than 585,000 US children eligible for such treatment, potentially costing over $11 billion/y.
Methods: To quantify the relative impact of patient physiological indicators, physician characteristics, and consumer preferences on referrals to endocrinologists (and potential access to GH) for short children, a national study of 1268 randomly selected US pediatricians was conducted, based on a full factorial experimental design in a structured survey.
Results: While patient indicators (height, growth pattern) influenced referrals (P < 0.001), consumer drivers (family concern) and physician attitudes had almost as great an impact—especially for children with less severe growth impairment (P < 0.001). Physician belief that short stature impairs emotional well-being and physician characteristics (female, older, shorter, beliefs about drug company information) increased referrals (P < 0.03–0.001)—independent of growth parameters.
Conclusions: Referral recommendations that create the pool of candidates for the specialty drug GH are heavily swayed by physician characteristics and consumer preferences, particularly in the absence of compelling physiological evidence. This makes most of children with short stature strikingly susceptible to nonphysiological influences on referrals that render them candidates for this specialty drug. Only 1 additional referral per US pediatrician would likely increase GH costs by over $100 million/y.