[Methodology for the elaboration of prognosis studies].

Prognostic studies are investigations to estimate the risk or probability of future outcomes in people with established disease. Ideally based on cohort studies where it is established: the time of onset or analysis of the evolution of a disease, the follow-up period for the outcome of interest, the type of outcome and the prognostic factors or markers to investigate. Ultimately, the decision on how to run and analyze forecast studies will depend on their purpose: exploratory, explanatory, or predictive.