A method may include displaying to a user an interface at which the user inputs a fear of hypoglycemia index (FHI), the FHI corresponding to an acceptable probability of a blood glucose level being below a threshold blood glucose level. The method may also include receiving blood glucose data for a person with diabetes (PWD). The method may additionally include calculating a probability of the PWD having a blood glucose level below the threshold blood glucose level based on the variability of the received blood glucose data. The method may also include setting one or more target blood glucose levels to align the probability of the PWD having a blood glucose level below the threshold blood glucose level with the acceptable probability associated with the user input FHI. The method may additionally include delivering insulin, using the insulin delivery device, based on the target blood glucose level.