Therapy assist information and/or tracking device and related methods and systems

A pen cap for an insulin pen comprising:

• at least one input device adapted to receive glucose data;
• at least one circuit adapted to detect at least one of a capping or decapping of the pen cap from an insulin pen;
• at least one user interface to communicate at least one of therapy relevant information, therapy recommendations, or a time of the at least one of a capping or decapping of the pen cap;
• memory to store at least one user-specific dosage parameter or recommended dose;
• and
• at least one processor adapted to determine content presented by the user interface, the processor using information relating to the at least one of a capping or decapping of the pen cap,
• wherein the pen cap is adapted to be responsive to the pen cap being capped on the insulin pen for at least a threshold period of time, and to display a recommended correction dose of insulin based on an insulin sensitivity factor and a target glucose value stored in memory.