Lower educational level is a possible risk factor for postoperative cognitive dysfunction after surgery under general anesthesia

Abstract

Introduction: Elderly patients with postoperative cognitive dysfunction (POCD) have an increased risk of mortality, especially after major surgery1. High educational level is regarded as a protective factor for developing dementia, especially Alzheirmer's disease2, but little is known about educational level in the development of POCD. Objective: This study aims evaluating the influence of the level of education in the incidence of POCD in elderly patients undergoing surgery under general anesthesia. Methods: Seventy one patients older than 60 years old undergoing surgery under general anesthesia were evaluated before surgery and on 7th postoperative (P.O.) day by TICS (Telephone Interview for Cognitive- Standardized, instrument that assesses by telephone the skills of spatial and temporal orientation and memory, requiring only the ability to verbal understanding). Low educational level (LEL) was defined as 4 or less years of formal education and high educational level (HEL) was defined as 8 or more years of formal education. Statistical analysis was performed with SPSS 17.0, using nonparametric analysis of ordinal data with repeated measurements. P values inferior to 0,05 were considered significant. Results: HEL and LEL groups presented different TICS values since preoperative period (P = 0.032). For comparison between pre and postoperative period, the HEL group presented TICS values of 29.8±5.9 before surgery and 29.0±7.3 at 7th P.O. and for LEL group the TICS values were 17.6±3.1 and 16.7±2.6, respectively, without difference between groups (P = 0.07). Conclusions: The differences in the TICS values observed since the preoperative period are normal for the educational levels evaluated3. Although the decreasing of mean TICS value of the LEL group (5.11%) was greater than the HEL group (2.68%), the sample size analyzed wasn't enough the prove that low educational level is a risk factor for POCD.