Setting the hemoglobin A1c target in type 2 diabetes: a priori, a posteriori, or neither?

Current guidelines specify hemoglobin A1c (HbA1c) targets around or less than 7.0 %, with more (<6.5 %) or less (<8 %) stringent goals being appropriate for selected patients. The difficulty in setting a precise HbA1c target depends, at least in part, on the physician perception of the relative importance of the parameters to be considered when determining the target. Using the "a priori" approach, physicians set the HbA1c target first, then prescribe the appropriate antidiabetic drug in order to cover the distance from the target, i.e., the difference between the current HbA1c value of the patient and the individualized HbA1c target: calculating the distance from the target may also be useful as a predictor of therapeutic success. In the "a posteriori" approach, physicians first prescribe, then decide if the achieved HbA1c is an appropriate level for that patient. Attainment of the HbA1c target ultimately depends on which target the physician set: both approaches ("a priori" and "a posteriori") may be useful for both physicians to make appropriate therapeutic decisions and patients to adhere to the best possible treatment. All this presumably will avoid unnecessary therapeutic inertia.