Methods and Applications of Statistics in Clinical Trials, Volume 2: Planning, Analysis, and Inferential Methods

Chapter 32

Pharmacoepidemiology, Overview

Samy Suissa

32.1 Introduction

Pharmacoepidemiology, the study of patterns of medication use in the population and their effects on disease, is a new field. The need for this area of research became evident in 1961, during the thalidomide catastrophe, when it was realized that drugs prescribed for therapeutic purposes could produce unexpected risks. The entry of thalidomide, a new hypnotic drug, on the market was accompanied by a sudden sharp increase in the frequency of rare birth defects, characterized by the partial or complete absence of limbs [29,31]. Consequently, several countries either instituted agencies to regulate drugs or expanded the mandate of existing agencies [51]. These agencies were previously interested only in the demonstration of a drug’s efficacy but now required proof of a drug’s safety before it was tested in humans let alone before it was marketed for use by the general population. These proofs of safety, based on toxicological and pharmacological studies, were necessary before randomized controlled trials (RCTs) could be conducted on human subjects, primarily to demonstrate the efficacy of a drug.

The use of the epidemiological approach to characterize population patterns of medication use and to assess their effects developed as a complement to RCTs for several reasons. First, RCTs were designed to assess the efficacy and effectiveness of a drug, providing as well some data on its safety with respect to commonly ...