That is the question of interest of a new study by Snider et al. (2018) in Value in Health. The authors use six reviews by the Institute for Clinical and Economic Review (ICER) that forecast the likely national spend on specific drugs or drug classes as case studies. Their study compares these forecast to subsequent real-world use.
ICER’s uptake estimates exceeded real-world estimates by factors ranging from 7.4 (sacubitril/valsartan) to 54 (hepatitis C treatments). The “unmanaged uptake” assumption (removed from ICER’s approach in 2017) yields large deviations between BIM [budget impact model] estimates and real-world consumption. Nevertheless, in some cases, ICER’s BIMs that relied on current market estimates also deviated substantially from real-world sales data.
Note that this study was funded by the Innovation and Value Initiative (IVI), where I serve as the Director of Research.
Source:- Snider JT, Sussell J, Tebeka MG, Gonzalez A, Cohen JT, Neumann P. Challenges with Forecasting Budget Impact: A Case Study of Six ICER Reports. Value in Health. 2018 Dec 14.