Each AFND level tackles one or multiple challenges illustrated here by an 'X'. In order to respect confidentiality due to security-sensitive patient data and avoid the contractual agreement of data transfers between the data-owning institution and the data-hosting institution, individual data are often confined to data-owning institution. In addition, centralization implies a transfer of the privacy breach, a risk of data loss and an implicit loss of usage control. Risk of re-identification is not addressed by distribution