A diabetes care management system for managing blood glucose levels associated with diabetes, comprising a computing device and an insulin delivery device. The computing device generally includes (i) a memory comprising one or more optimal blood glucose values, one or more insulin dose values of a patient, one or more measured blood glucose values, and one or more scaling factors for weighting the impact on a future blood glucose value and that are customizable to an individual patient to predict the effect on the blood glucose of insulin dose actions performed by the individual patient, (ii) a microprocessor, in communication with the memory, programmed to calculate a further value, the further value being based on the insulin dose values, the optimal blood glucose values, and the scaling factors, (iii) a display configured to display information according to the further value, and (iv) a housing, wherein the memory and the microprocessor are housed within the housing, thereby providing a hand-held, readily transportable computing device. The insulin delivery device may deliver insulin in response to information associated with the further value.