Comparing jurisdiction-specific pharmaco-economic evaluations using medical purchasing power parities.

Objectives: To demonstrate how medical purchasing power parities (mPPP) may harmonize economic evaluations from different jurisdictions and enable comparisons across jurisdictions.
Methods: We describe the use of mPPPs and illustrate this with an example of economic evaluations of nab-paclitaxel with gemcitabine (Nab-P + Gem) versus gemcitabine monotherapy in the setting of metastatic pancreatic cancer. Following a literature search, we extracted data from cost-effectiveness studies on these treatments performed in various countries. mPPPs from the Organization for Economic Co-operation and Development were used to convert reported costs in the jurisdiction of origins to US dollars for the most current year using two possible pathways: (1) reported costs first adjusted by mPPP then adjusted by exchange index; and (2) reported costs first adjusted by exchange index then adjusted by mPPP.
Results: Despite many of the pharmaco-economic evaluations sharing similar assumptions and inputs, even after mPPP conversion, residual heterogeneity was attributable to perspectives, discount rate, outcomes, and costs, among others; including in studies conducted in the same jurisdiction.
Conclusion: Despite the methodological challenges and heterogeneity within and across jurisdictions, we demonstrated that mPPP offers a way to compare economic evaluations across jurisdictions.