A security system for medical data comprising: - a portable medical device for measuring medical parameters being indicative of a physiological state of a mammal; and - a server device, the server device comprising and/or being operatively coupled to a storage device, the server device hosting an accounts manager of a diabetes management system, wherein the accounts manager is configured to manage accounts stored on said storage device, said accounts comprising a first account associated with a healthcare provider and a plurality of patient accounts associated with said first account, each patient account comprising medical data of a respective patient; - a mobile device hosting an application program, said application program being interoperable with the portable medical device and with the accounts manager, the mobile device being connected with the server device via a network; wherein the portable medical device is configured to repeatedly measure medical parameters of one of said patients; wherein the application program is configured to repeatedly and fully automatically receive the measured medical parameters from said measurement device and is configured to immediately forward the received measured medical parameters to the accounts manager for storing said parameters on the storage device of the server as part of the patient account of said patient, characterized in that the portable medical device, the application program and the accounts manager are configured such that only a single copy of the measured medical data is permanently stored in said storage device and such that any temporally created copies of said measured medical data are immediately erased from the portable medical device and the mobile device after execution of the forwarding; wherein the account manager is configured to execute the following steps: - receiving a request to deactivate a first account; - removing access to data associated with the first account; - identifying each of the patient accounts associated with the first account and deactivating each of the identified patient accounts; - sending an electronic notification to the patients associated with each of the identified patient accounts, where the electronic notification advises the patient that the corresponding patient account has been deactivated; - creating an audit record in a data store, where the audit record indicates the deactivation of the first account; and - sending a termination command to the application programs of the patients associated with each of the identified patient accounts, wherein the application programs are configured such that they immediately terminate forwarding of medical measurement data to the accounts manager upon receiving the termination command. - a portable medical device for measuring medical parameters being indicative of a physiological state of a mammal; and - a server device, the server device comprising and/or being operatively coupled to a storage device, the server device hosting an accounts manager of a diabetes management system, wherein the accounts manager is configured to manage accounts stored on said storage device, said accounts comprising a first account associated with a healthcare provider and a plurality of patient accounts associated with said first account, each patient account comprising medical data of a respective patient; - a mobile device hosting an application program, said application program being interoperable with the portable medical device and with the accounts manager, the mobile device being connected with the server device via a network; - receiving a request to deactivate a first account; - removing access to data associated with the first account; - identifying each of the patient accounts associated with the first account and deactivating each of the identified patient accounts; - sending an electronic notification to the patients associated with each of the identified patient accounts, where the electronic notification advises the patient that the corresponding patient account has been deactivated; - creating an audit record in a data store, where the audit record indicates the deactivation of the first account; and - sending a termination command to the application programs of the patients associated with each of the identified patient accounts, wherein the application programs are configured such that they immediately terminate forwarding of medical measurement data to the accounts manager upon receiving the termination command.