A Model To Estimate Drug Plan Cost Savings From a Trial Prescription Program

Abstract

OBJECTIVE: To develop a model to estimate potential drug-plan cost savings from a trial prescription program, to test the model using data from existing trial prescription programs, and to determine the sensitivity of predicted cost savings to variation in program parameters. DESIGN: Information on trial prescription programs was obtained from the published literature, project reports, and personal communications with program administrators. Conceptual models of the determinants of trial prescription initiation and discontinuation were used to guide the development of a spreadsheet-based cost estimation model that used prescription claims data. The model was tested by comparing predicted to actual cost savings for a trial prescription program in a private drug plan. Sensitivity analyses were performed to determine critical model inputs. SETTING: Provincial pharmacy associations and other organizations known to have developed or participated in trial prescription programs. RESULTS: Inaccurate estimates of eligible prescriptions and their average daily drug cost, possibly attributable to a change in insurer, resulted in an inaccurate prediction of net cost savings. Model results were sensitive to trial-entry rate, discontinuation rate, daily drug cost, and the number of days supply dispensed in the absence of a trial. CONCLUSION: To achieve maximal return on investment, trial prescription programs should target drugs with high cost and adverse-effect rates. Before trial prescription programs can be fully endorsed as a managed care strategy, however, peer-reviewed research is needed.