Observational studies: They improve the knowledge of the disease and its evolution over time. They are carried out within the framework of the follow-up of the patients in the reference centers.
Interventional studies or clinical trials: They provide scientific evidence of the efficacy and safety of a new drug, a new care device or a new management in the context of an illness. This is the necessary step for a new molecule to become a drug or a new medical device to be marketed.