In a series of recent papers, I have made three arguments about how to define “disease” and evaluate and apply possible definitions. First, I have argued that definitions should not be seen as traditional conceptual analyses, but instead as proposals about how to define and use the term “disease” in the future. Second, I have pointed out and attempted to address a challenge for dysfunction-requiring accounts of disease that I call the “line-drawing” problem: distinguishing between low-normal functioning and dysfunctioning. Finally, (...) I have used a dysfunction-requiring approach to argue that some extremely prevalent conditions, such as high blood pressure, high cholesterol, and ductal carcinoma in situ, are not diseases, but instead are risk factors. Four of the papers in this issue directly engage my previous work. In this commentary, I applaud the advances these authors make, address points of disagreement, and make suggestions about where the discussion should go next. (shrink)

Overdiagnosis refers to diagnosis that does not benefit patients because the diagnosed condition is not a harmful disease in those individuals. Overdiagnosis has been identified as a problem in cancer screening, diseases such as chronic kidney disease and diabetes, and a range of mental illnesses including depression and attention deficit hyperactivity disorder. In this paper, we describe overdiagnosis, investigate reasons why it occurs, and propose two different types. Misclassification overdiagnosis arises because the diagnostic threshold for the disease in question has (...) been set at a level where many people without harmful disease are nonetheless diagnosed. We illustrate misclassification overdiagnosis using the example of chronic kidney disease. Misclassification occurs in diseases diagnosed using biomarkers or based on patient reported phenomena. Maldetection overdiagnosis arises because, at the time the diagnosis is made and despite the presence of a 'gold standard' diagnostic test, it is not possible to discriminate between harmful and non-harmful cases of the index disease. We illustrate maldetection overdiagnosis using the example of thyroid cancer. While there is some overlap between misclassification and maldetection overdiagnosis, this conceptual analysis helps to clarify the phenomenon of overdiagnosis and is a necessary first step in developing strategies to address the problem. (shrink)

Overdiagnosis and disease are related concepts. Widened conceptions of disease increase overdiagnosis and vice versa. This is partly because there is a close and complex relationship between disease and overdiagnosis. In order to address the problems with overdiagnosis, we may benefit from a closer understanding this relationship. Accordingly, the objective of this article is to elucidate the relationship between disease and overdiagnosis. To do so, the article starts with scrutinizing how overdiagnosis can explain the expansion of the concept of disease. (...) Then it investigates how definitions of disease address various challenges of overdiagnosis. The article specifically investigates recent attempts to clarify the relationship between the concepts of disease and overdiagnosis. Several shortcomings are identified and lead to a closer analysis of overdiagnosis in the diagnostic process. Contrary to recent contributions to the field, it is argued that cases of overdiagnosis are not cases of disease. They are non-verified labelling of disease. It is revealed how overdiagnosis establishes an unwarranted link between indicative phenomena, such as polyps or cell changes, and harm, and thereby generates a link to disease. One implication of this study is that we should stop attributing disease language to indicative phenomena. That is, we should stop calling it “cancer screening” when we are actually searching for polyps. Another implications is that we should strive for scientific progress in differentiating phenomena that are of negative value to us from those that are not. In overdiagnosis we diagnose something that is not disease: it is over-diagnosis. (shrink)