A method includes receiving measurements from a sensor associated with a patient at a portable medication delivery device. The method also includes controlling delivery of medication to the patient at the portable medication delivery device using a single input, single output (SISO) model predictive control technique. The SISO model predictive control technique includes predicting a characteristic of the patient using the measurements and a model associated with the patient. The SISO model predictive control technique also includes determining whether the characteristic of the patient is predicted to fall outside of a desired range. In addition, the SISO model predictive control technique includes, if the characteristic of the patient is predicted to fall outside of the desired range, determining an amount of medication to deliver to the patient and delivering the determined amount of medication to the patient.