Challenge of Evidence in Individualized Medicine

Kathleen Kraft; Wolfgang Hoffmann


Personalized Medicine. 2012;9(1):65-71. 

In This Article

Why Are Guidelines Hardly Applied in Practice?

Both significance and areas of application of EBM in health are presently matters of debate. Studies trying to assess the practical implementation of guidelines vary widely depending on setting, design, methodology and definition of evidence.[8,9] Often, only a few services of healthcare are evidence-based.[10] But why is only such a small part of medical services evidence-based? Why are guidelines underappreciated in everyday practice? Heidrich et al. investigated knowledge and perception of guidelines performed among general practitioners (GPs) and internists in private practice. In this study, it was observed that many physicians do not treat patients with coronary heart disease according to national or international guidelines even though it is well known that adherence to guidelines improves cardiovascular risk factor treatment in a typical patient. Main barriers to the implementation were lack of reimbursement, lack of patient compliance and oversized guidelines that GPs have no time to read.[11] The results are comparable to those of Kendall et al., who found that the reasons for GPs not following the guidelines are lack of motivation, awareness or self-efficacy to apply evidence.[12] There is general consensus that the result of a well-designed, prospective randomized, placebo-controlled trial published in a high-quality journal should have an impact on the practice of physicians. However, the transferability of the researcher results depends on a variety of contextual factors. A 'desperate academic researcher'[13] may feel he has to publish the data in order not to fail. Employees of the pharmaceutical industry want to distribute the products of their own company. These are not exceptions – in many cases the derivation of evidence of a published study may be influenced by personal or economic interests.[13]

Another problem of guidelines is that they often show only small differences between two forms of therapy that attain statistical significance based on large-study populations rather than clinical relevance. Small differences, however, may not actually show in GPs daily practices where they are dealing with individual patients who may differ in many ways from the homogenous study population in a randomized clinical trial (RCT).[14] In addition, the still poor implementation of evidence-based guidelines in clinical routine contributes to the fact that the recommended treatment of 'every day patients' – many of which are frail, elderly and multimorbid patients – may or may not benefit from this treatment.[15] Owing to multiple competing risk factors and comorbidities this population very often does not meet inclusion criteria of the RCT and therefore are not mirrored in the guidelines.[16,17]

Not only many physicians, but also health insurances do not always follow guidelines. One recent example is the evidence-based guideline for the prevention and therapy of obesity published in 2007 the benefit of commercial weight-loss programs is graded with high-evidence level (WeightWatchers®: 1b, Optifast 52-program®: 2b).[18,19] Although obesity is a chronic disease with a high prevalence leading to impaired quality of life, high morbidity and increased mortality,[20] most health insurances do not currently reimburse any costs of these weight-loss programs.[21]