Routine diabetes education will given to the patients included in the Control Group by a diabetes education nurse. The diabetes education nurse has been working for 10 years in the same center.

Intervention Group will take their diabetes education by teach-back educational strategy.

In the teach-back method, after teaching new information to the patient, the patients were asked to explain that new information in their own words. Then the patients' knowledge and the adequateness of their explanations were determined. The patient should repeat the instructions in their own words. In this way, the healthcare professional can evaluate how the patient understands the information. If the patient repeated the information correctly, the teach-back phase for that information was completed, and progression for new information was resumed. However, if there was a deficiency or error in the information, it was corrected and repeated by the healthcare professional.

The DKL will be measured through a self-structured questionnaire containing 11 items. The questionnaire contains three answers: "yes," "no," or "I do not know." The right answer will be accepted as two points, the wrong answer as zero points, and the "I do not know" answer will be accepted as one point. The total scores ranges from 0-22. Higher scores of the questionnaire indicates that the higher DKL.

Fasting blood glucose in mg/dl

HbA1c in %