Comparative Effectiveness Research: Finding the best evidence to answer
Comparative Effectiveness Research is receiving greater attention for its potential role in healthcare reform and in improving the quality and efficiency of healthcare delivery in this country. The Federal Coordinating Council for Comparative Effectiveness Research has defined Comparative Effectiveness as “the conduct and synthesis of research comparing the benefits and harms of different interventions and strategies to prevent, diagnose, treat and monitor health conditions in “real world” settings. The purpose of this research is to improve health outcomes by developing and disseminating the best and most relevant evidence to patients, clinicians, and other decision-makers, responding to their expressed needs, about which interventions are most effective for which patients under specific circumstances.” Under the Effective Health Care Program (EHC), AHRQ’s Evidence-based Practice Centers (EPCs) publish Comparative Effectiveness Reviews. The aim of these reviews is to describe the breadth of benefits and harms of a particular intervention in comparison with other available alternatives. The EHC Program has a number of partners and stakeholders who find that this information is important and helpful to their patients, providers, and other decision-makers in answering questions and making their decisions. Unfortunately, there is rarely a sufficient body of head-to-head trials to support easy conclusions about comparative benefits and harms. In the absence of the ideal pragmatic clinical trial comparing interventions and measuring long term outcomes in the particular population of interest, EPCs must often consider other forms of evidence in trying to answer the important questions. Often the best available evidence may be indirect evidence from trials of surrogate outcomes, trials of indirect comparisons, trials in different populations, or observational studies, which may be more prone to bias. Even in the face of insufficient head-to-head trials, systematic reviews have rarely incorporated studies of indirect comparisons (Glenny, 2005). However, in order to improve the ability to answer important comparative effectiveness questions, we need to fully understand and improve the methods for using indirect evidence or observational studies to answer these questions. Improving methods for using mixed-treatment meta-analysis has the potential for improving our ability to answer important comparative effectiveness questions.