In previous post, I provided a diagram distinguishing what I called the Wellness Domain from what I called the Overt Disease Domain (see: Wellness, Preventive Medicine, and the Classic Disease Model). I followed up on this note with another one (see: Genomic Testing, Pre-Symptomatic Disease, and Health Insurance) in which I made the following statement:
...[G]enomic medicine is identifying people with a predisposition to disease and the Early Health Model is identifying people with early forms of disease as manifested by biomarker abnormalities. For the present, such "healthcare consumers" (not patients) are best categorized as being "well" because we are uncertain how many of them will go on to develop overt symptomatic disease. Also implicit in this statement is that we also don't know which of these patients with early forms of disease and a predisposition to disease to treat.
To restate this previous thought, I placed those individuals with a either a predisposition to disease or pre-disease (pre-symptomatic, pre-clinical disease but with abnormal biomarkers suggesting some degree of pathophysiology) into the wellness domain and contrasted them with "sick" patients who have clinically manifest acute or chronic illnesses. This approach got me more interested in the continuum of health from perfect wellness to a pre-disposition to disease to pre-disease to overt acute and finally chronic disease. In order to better understand and further explore this health continuum, I developed another diagram that is presented below. In a previous note, I also made reference to Siemens' references to the continuum of health in a previous posted note (see: Siemens as the "First Full Service Diagnostic Company").
In this new diagram, I have arranged wellness, predisposition to disease, pre-disease, and overt disease on a horizontal axis. As you can see, there are both genetic and non-genetic factors that predispose an individual to the development of a disease. I define a pre-disease as the diagnosis of a disease by lab testing or perhaps molecular imaging but without any overt signs and symptoms of it. Note in this diagram that I indicate that the need for treatment or therapy, marked by the "Rx" symbol, is questioned at this time for both patients with a predisposition to disease and also a diagnosed pre-disease.
Currently, one of the most interesting questions associated with the early disease model is whether it is appropriate to treat patients with pre-diseases. If they are deemed treatable and as we come to better understand the nature of pre-disease, a second question is what drugs to treat them with. As soon as we work out this question, we will then be faced with the new question of how and when to treat patients with a predisposition to disease, genetic or otherwise.