The Complexities of Comparative Effectiveness

Executive Summary The purpose of this white paper is educational. It is designed to impart a better understanding of what is meant by the term comparative effectiveness and to communicate the complexities that surround it. The primary purpose of comparative effectiveness research is to inform healthcare related decisions. While comparative effectiveness can be a valuable tool to inform the decision making of the clinician and the patient, it can not provide simple, " one size fits all " answers. The paper demonstrates that the seemingly simple idea of comparative effectiveness is actually quite complex. The issues surrounding the implementation of comparative effectiveness studies include, but are not limited to: • There is no standard definition for comparative effectiveness. • Given that healthcare providers and patients do not currently utilize all relevant information, it is unclear how findings from new comparative effectiveness studies will impact clinical practice. • The types of studies that may be used to produce comparative effectiveness results face significant challenges and have many limitations. • Population-based study results may not be applicable to the needs of the individual patient. • The absence of finding statistically significant differences among treatments does not mean that the outcomes of the compared treatments are the same. • Patient treatment self-selection may affect comparative effectiveness results. For many of these issues, there is no single correct way to conduct the study. Rather, the strategy that one should employ is dependent on who is asking the question, the patient population under evaluation and for what purpose the answer will be utilized. The paper is not an exhaustive review of comparative effectiveness. In particular, it does not aim to analyze the existing international implementations of comparative effectiveness or the practical institutional difficulties and potential pitfalls of implementing comparative effectiveness. Rather, the paper is focused on examining some of the conceptual complexities inherent in comparative effectiveness analysis and should serve as a basis to begin understanding the topic of comparative effectiveness and the related complexities.