Evaluating the role of bias in pharmacoeconomic studies.

Pharmacoeconomic research is conducted to provide patients, physicians, institutional providers, health benefit plan decision makers, and government authorities with information about the economic value of pharmaceuticals. Valid and appropriate pharmacoeconomic data are vital to informed decision making. Methodological guidelines have been proposed for the conduct of pharmacoeconomic research to foster high quality and minimize bias. This article outlines the types of bias that are introduced in pharmacoeconomic studies using a traditional epidemiological approach.