Predictors of Prescriber Preference for Expensive Insulins: A Single Institution Survey

The average cost of insulin has increased greatly recently, partly due to prescription of newer expensive insulins. This has caused insulin underuse among economically vulnerable uninsured patients. Herein, predictors of preference for expensive (higher retail price) insulins among primary care physicians are investigated.

Internal medicine and family medicine attending physicians and residents at West Suburban Medical Center (Oak Park, Illinois, USA) participated in a web-based survey (Qualtrics Survey Platform) via email between October 20, 2020, and November 10, 2020. Baseline characteristics, prescribing preferences (Insulins Ranks, lower rank indicates higher preference), factors determining insulin choice, pricing knowledge, dosing knowledge, and training were recorded. Insulins were classified as "Inexpensive" (retail price ≤ median insulin price) or "Expensive." The mean rank of expensive and inexpensive insulins prescribed were calculated. Participants were divided into either the "Inexpensive Prescription Preferences" (IPP; mean rank of Inexpensive insulins ≤ mean rank of Expensive insulins) or "Expensive Prescription Preferences" (EPP) groups. Groups were compared. Multivariable logistic regression assessed predictors of IPP.

The response rate was 78% (72/92). Among the 70 participants included, EPP (n = 43) and IPP participants (IPP, n = 27) had similar baseline characteristics (Physician Role, Specialty, and Practice Type), except EPP physicians graduated earlier (P = 0.011). EPP participants reported prescribing insulin glargine more often (P = 0.018) and also ranked it higher (P < 0.001). Logistic regression identified that previous Endocrine rotations (P = 0.031) and senior Physician Role (P = 0.001) predicted EPP.

Previous endocrinology rotations, and senior role predict prescription of insulins with a high retail price. Speculatively, training physicians in cheaper prescription practices may lower costs. Further studies are required to generalize these results.