Fig. 1

Example of disease stages. Scheme showing two ways of setting up the stages of a disease taking MDS case as example. In both cases the stages must be placed in progressive order considering one initial stage, usually taken as control or normal stage, and one terminal stage that usually corresponds to the most severe or acute stage of the disease (Acute Disease). The stages are considered as discrete –i.e. not as continuous variables– and independent –since they correspond to the evolution measured in different individuals–. a An example for 6 stages taken from the MDS case, considering different disease subtypes. b An example for 4 stages taken from the MDS case, considering only low-risk and high-risk subtypes