A tale of two (or more) cities: geographic transferability of pharmacoeconomic data.

The economic evaluation of a new medicine often must be based on data gathered in multiple countries. Because replication of trials is an expensive and inefficient undertaking, analysts need to determine the validity of transferring cost-effectiveness data from one country to another. Threats to transferring data involve differences among countries with regard to demography and epidemiology of disease, clinical practice and conventions, incentives to and regulation of healthcare providers, relative price levels, consumer preferences, and opportunity cost of resources. Because of these differences, a drug can be cost-effective in one country and not cost-effective in another. Adapting a cost-effectiveness study conducted in one country to another country requires careful scrutiny of the relevance of comparators, practice patterns, and relative price weights.