Boorse’s biostatistical theory states that diseases should be defined in ways that reflect disturbances of biological function and that are objective and value free. We use three examples from contemporary medicine that demonstrate the complex issues that arise when defining the boundaries of disease: polycystic ovary syndrome, chronic kidney disease, and myocardial infarction. We argue that the biostatistical theory fails to provide sufficient guidance on where the boundaries of disease should be drawn, contains ambiguities relating to choice of reference class, (...) and is out of step with medical processes for identifying disease boundaries. Although proponents of the biostatistical theory might regard these practical issues as irrelevant to the aim of providing a theoretical account of disease, we take them to indicate the need for a theoretical account that is adequate for current needs—including limiting new forms of medicalization that are driven by the identification of disease based on dysfunction. Our processes for determining the boundaries for disease need to recognize that there is no value-free method for making these decisions. (shrink)

Overdiagnosis is an emerging problem in health policy and practice: we address its definition and ethical implications. We argue that the definition of overdiagnosis should be expressed at the level of populations. Consider a condition prevalent in a population, customarily labelled with diagnosis A. We propose that overdiagnosis is occurring in respect of that condition in that population when the condition is being identified and labelled with diagnosis A in that population ; this identification and labelling would be accepted as (...) correct in a relevant professional community; but the resulting label and/or intervention carries an unfavourable balance between benefits and harms. We identify challenges in determining and weighting relevant harms, then propose three central ethical considerations in overdiagnosis: the extent of harm done, whether harm is avoidable and whether the primary goal of the actor/s concerned is to benefit themselves or the patient, citizen or society. This distinguishes predatory, misdirected and tragic overdiagnosis; the degree of harm moderates the justifiability of each type. We end with four normative challenges: methods for adjudicating between professional standards and identifying relevant harms and benefits should be procedurally just; individuals, organisations and states are differently responsible for addressing overdiagnosis; overdiagnosis is a matter for distributive justice: the burdens of both overdiagnosis and its prevention could fall on the least-well-off; and communicating about overdiagnosis risks harming those unaware that they may have been overdiagnosed. These challenges will need to be addressed as the field develops. (shrink)