The Disease Map
The introduced disease maps visualise how human disorders are ‘positioned’ against each other in a population with respect to an individual biological organism. It is well known that many human disorders are risk factors for or consequences of other disorders. While many of such positive associations between disorders are well known and understood, many remain either entirely unnoticed or not properly recognised. Moreover, it is reasonable to assume that certain human disorders can be associated negatively, that is, a person being affected with A, has decreased chances to get affected with B (can be, but not necessary, vice versa). The presented visualisation is a novel tool for validating already known as well as discovering new, never noticed, empirical association patterns between human disorders. While some of such patters can reflect specifics of a healthcare system, many can reveal interesting biological phenomena relevant practically. Each circle on the map represents a single human disorder as classified according to ICD9-CM (International Classification of Diseases, Ninth Revision, Clinical Modification). A circle size reflects (3-year) empirical prevalence of a disease in a given age/gender group, while a colour corresponds to one of 17 specific ICD9-CM categories of diseases (Figure 1). Knowing observed strengths of associations between each pair of disorders, we define expected distances between each circle – the stronger the association the shorter the distance. Further, each circle is positioned according to multiple connections to others such that to minimise the cumulative deviation in expected distances. Thus, a position of each circle is determined by multiple connections to other circles. As a result, the entire system takes a certain shape determined by strengths of pairwise associations. This will be added to Healthcare Resources Subject Tracer™ Information blog.