lowing section describes issues undermining the trustworthiness and impact of CPGs (illustrated in the case studies presented in Boxes 3-1, 3-2, and 3-3), including many associated with the guideline development process. These issues include limitations in the scientific evidence on which CPGs are based; lack of transparency of development groups’ methodologies, especially in deriving recommendations and determining their strength; conflicting guidelines; and challenges of conflict of interest (COI). Additional factors threatening CPG trustworthiness and influence are reflected in tensions among guideline developers and users with respect to balancing desires for evidence-based recommendations with clinician desires for guidance on clinical situations in which great uncertainty exists. Resource limitations in guideline development and updating present further challenges to the promise of high-quality, effective guidelines. Overall, though researchers have reported empirical evidence of modest gains in guidelines’ quality, there is substantial room for improvement (Shaneyfelt and Centor, 2009). The committee did not identify comprehensive and adequate standards for development of unbiased, scientifically valid, and trustworthy CPGs. Hence, the committee formulated and proposed new standards for developing trustworthy CPGs, as explained in the following two chapters.
Appreciation for evidence-based medicine has grown over the past several decades, due in part to increased interest in and funding for clinical practice research, and improvements in associated research methodologies. However, many CPG experts and practicing clinicians increasingly regard the scientific evidence base with suspicion for a variety of reasons, including gaps in evidence, poor-quality research and systematic reviews, biased guideline developers, and the dominance of industry-funded research and guideline development. A 2005 study found that industry sponsored approximately 75 percent of clinical trials published in The Lancet, New England Journal of Medicine, and Journal of the American Medical Association (The House of Commons Health Committee, 2005). Two-thirds of this industry-sponsored published research is directly conducted by profit-making research companies and one third by academic medical centers. Furthermore, even high-quality commercial clinical investigations (e.g., those included in Cochrane Reviews) are