In the domain of medical science, factual evidence is usually considered as the criterion on which to base decisions and construct hypotheses. Evidence-based medicine is the translation of this approach into the field of patient care, and it means providing only the type of care that is based on evidence that proves its effectiveness and appropriateness. However, while the literature has focused on the types and force of evidence used to establish the recommendation and treatment guidelines, the problem of how (...) evidence is used in doctor–patient interactions to motivate, or refuse, treatment or habit change has been almost completely neglected. In this specific context, characterized by the epistemic unbalance between the interlocutors and a specific conversational goal, the scientific categories of evidence are often irrelevant. The goal of this paper is to address this challenge by analyzing the role evidence plays in doctor–patient interactions in diabetes care. After introducing an analytical distinction between the epistemic and the pragmatic aspect of evidence, we will propose a classification of the types and functions of evidence in chronic care communication, and illustrate its possible uses through its application to our corpus of diabetes-care consultations. From our qualitative analyses, it is possible to observe how in this communicative context a crucial role is played by the conflicts of evidence, in which providers correct patients’ uses of evidence leading them to using less defeasible levels of evidence. (shrink)

Hierarchies of evidence are an important and influential tool for appraising evidence in medicine. In recent years, hierarchies have been formally adopted by organizations including the Cochrane Collaboration [1], NICE [2,3], the WHO [4], the US Preventive Services Task Force [5], and the Australian NHMRC [6,7]. The development of such hierarchies has been regarded as a central part of Evidence-Based Medicine, a movement within healthcare which prioritises the use of epidemiological evidence such as that provided by Randomised Controlled Trials. Philosophical (...) work on the methodology of medicine has so far mostly focused on claims about the superiority of RCTs, and hence has largely neglected the questions of what hierarchies are, what assumptions they require, and how they affect clinical practice. This thesis shows that there is great variation in the hierarchies defended and in the interpretations they are, and can be, given. The interpretative assumptions made in using hierarchies are crucial to the content and defensibility of the underlying philosophical commitments concerning evidence and medical practice. Once this variation is been identified, it becomes clear that the little philosophical work that has been done so far affects only some hierarchies, under some interpretations. Modest interpretations offered by La Caze [11], conditional hierarchies like GRADE [12-14], and heuristic approaches such as that defended by Howick et al. [15,16] all survive previous philosophical criticism. This thesis extends previous criticisms by arguing that modest interpretations are so weak as to be unhelpful for clinical practice; that GRADE and similar conditional models omit clinically relevant information, such as information about variation in treatments’ effects and the causes of different responses to therapy; and that heuristic approaches lack the necessary empirical support. The conclusion is that hierarchies in general embed untenable philosophical assumptions: principally that information about average treatment effects backed by high-quality evidence can justify strong recommendations, and that the impact of evidence from individual studies can and should be appraised in isolation. Hierarchies are a poor basis for the application of evidence in clinical practice. The Evidence-Based Medicine movement should move beyond them and explore alternative tools for appraising the overall evidence for therapeutic claims. (shrink)