73 A new explanatory approach to overdiagnosis, based on the bubble theory, using osteoporosis as an example

Objectives Many individual drivers for overdiagnosis have been identified. Out of those, the economical one has been considered the strongest with the global market of pharmaceuticals now valued at 1.000 billion U.S. dollars and is expected to grow to 1.300 billion in 2020. Despite the common awareness of the above, studies so far lack a more coherent approach explaining the structures and dynamics in society that facilitate overdiagnosis rather than examining its single driver alone. The following study offers a more comprehensive explanation to overdiagnosis, by approaching the concept with the economical point of view as the major tool. Osteoporosis, which is widely accepted as an overdiagnostic condition, is used as an example. The suggested approach opens a new possibility to identify regulations that are needed in order to reduce overdiagnosis and its undesired consequences. Method The analysis is based on abductive methodology, in which evidence about osteoporosis is contextualised into the interdisciplinary bubble theory. This economic theory explains how economical assets are being traded at prices significantly departing from their fundamental value, which constitutes a potential risk of creating a bubble. Latest well-known bubble was the financial crunch in 2008. Recently, the theory has been extrapolated to explain situations in also other fields than finance, such as scientific bubbles, political bubbles and information bubbles. The inflated value of a specific entity, due to various facilitating elements, is what these non-financial scenarios have in common with the financial bubbles. The presented study applies the facilitating elements known from bubble theory to the empirical evidence from osteoporosis. Furthermore, it evaluates the consequences of overdiagnosis in the selected case and its relevance to the other bubbles. Results Doctors, patients, pharmaceutical industry, patient associations etc. all have a stake in the use of the osteoporosis diagnosis. Therefore, they may be considered as distinct actors. The concept of speculation – profiting from trade of the asset instead of its use – correlates with the three main reasons for overdiagnosis (disease mongering, lowering thresholds and over-detection) that are all evident in the case of osteoporosis. Similarly to the financial market, the medical market for osteoporosis seems to be configured in ways to boost the use of the diagnosis. Actors in financial markets are susceptible to social influence and so it seems, in general, in the medical field. By the very definition of a bubble, it can be argued that the development of osteoporosis diagnosis can be seen as one. Conclusions Although there are many similarities, the analogy between bubbles in finance and the situation of osteoporosis as an overdiagnostic condition is not perfect. That is mainly because of insufficient solid and consistent theory of bubbles. However, the bubble theory does offer a new approach to explain overdiagnosis with a more coherent explanation than just study of individual drivers. Furthermore, this new approach shows the value of interdisciplinary research in order to understand complex phenomena such as overdiagnosis, by complementing the empirical evidence with theory from other scientific spheres.