Cost minimisation analysis – a simple concept, yet difficult to implement. Too simple CMA can lead to unauthorized conclusions.
Authors: Plisko Robert , Drzał Robert , Władysiuk Magdalena , Bernaszuk Ewelina , Lis Joanna 
Published: July 2023

Background: AOTMiT's Health Technology Assessment guidelines developed in Poland in 2007 along with their subsequent updates do not specify how a cost minimisation analysis should be carried out. Hence, there is a lot of latitude in terms of the manner in which it is developed. Authors of specific cost minimisation analyses should adjust the methodology of their analysis to ensure that its utility for the decision-maker is as high as possible, and the best solution is selecting such a methodology which reflects the clinical reality best. In line with the NICE methodology, a cost minimisation analysis can be carried out only when there is strong evidence supporting lack of differences between the compared health interventions. Methods: The objective of this article is to present a critical assessment of the methodology of two CMAs on the example of selected economic analyses published on the AOTMiT website (along with verification analyses) together with proposal of their improvement [7, 9]. They were chosen due to the specificity of the health intervention they compare. The selected analyses compare health interventions differing in: the treatment regimens, route of administration and duration of use. The identified limitations of the analyses regarded the length of the time horizon adopted in the analysis, the cost calculation method or assessment of the justification of comparator selection. Results: The CMA for cladribine tablets is characterised by limitations associated both with the length of the time horizon and the cost calculation method. In the case of the cost minimisation analysis for cabazitaxel, the identified limitations are: taking into account the same treatment duration for the compared health interventions (an approach suggested in the AOTMiT's verification analysis [9]) and the use of treatment duration medians in calculations, which resulted in a one-year time horizon being adopted. In connection with the limitations identified in both analyses, the authors hereof have decided to adopt an approach which is the close to the actual situation on the example of cabazitaxel, in which the simplified modelling allows for reducing the impact of limitations identified in both CMAs (and the cabazitaxel verification analysis), related to the time horizon duration of the analysis, the calculation method, the use of medians and the right comparator selection. The statutory ex-factory price of cabazitaxel determined in the new analytical approach is nearly three-times higher (an increase by 169%) than the threshold price calculated by the AOTMiT. Conclusions: A simple cost minimisation in which the maximal cost of therapy incurred in a given time should be reserved solely for situation where obvious lack of differences has been demonstrated. In the case of developing a cost minimisation analysis for more complex cases, the analysis should be based on modelling of both effects and costs in a similar manner as a typical cost effectiveness/cost utility analysis.