HbA1c and Neurocognitive Disorders

Inclusion Criteria: * 1\) 45 - 80 years * 2\) American Society of Anesthesiologists physical status I to III * 3\) elective general, urological, gynecological and orthopedic surgery under general anesthesia * 4\) native speakers of the Greek language Exclusion Criteria: * 1\) refused to participate or sign the informed consent form * 2\) had undergone surgery or anesthesia within the last 30 days * 3\) had any prior or current history involving an affliction of the central nervous system * 4\) were diagnosed with severe cognitive decline based on the 16 - item Informant Questionnaire on Cognitive Decline (IQCODE - 16) * 5\) suffered from severe hearing or visual impairment * 6\) any psychiatric disorder * 7\) had a score \>5 in the Geriatric Depression Scale (GDS - 15) * 8\) or a score in females \< 4 males \< 2 in the Lawton - Brody Instrumental Activities of Daily Living Scale (I.A.D.L.) * 9\) reported alcohol consumption \> 35 units/week * 10\) drug dependence * 11\) had undergone previous neuropsychological testing * 12\) Diabetes Mellitus type II with \> 10 years of diagnosis * 13\) Diabetes Mellitus type I * 14\) Hemoglobin A1c (HbA1c) \> 7.5% * 15\) suffered from hemodynamical instability (\> 20% alterations of blood pressure perioperatively) * 16\) or desaturation (one or more events of SpO2 \< 80% for more than 2 minutes) peri-operatively * 17\) or blood loss of more than one unit