Preoperative Vitamin D Level is Associated with Postoperative Delirium After Cardiac Surgery in Patients Over 65 Years of Age

INTRODUCTION Delirium after cardiac surgery is a devastating and important complication. Delirium is defined as "disturbance in attention (i.e., reduced ability to direct, focus, sustain, and shift attention) and awareness (reduced orientation to the environment)." In this study, we analyzed the association of preoperative vitamin D levels and postoperative delirium after cardiac surgery in patients over 65 years. MATERIALS AND METHODS We retrospectively reviewed the data of 212 adult patients above 65 years of age who underwent isolated coronary artery bypass graft surgery from January 2016 to January 2018. The mean age for Group I was 69.7 ± 7.4 and Group II was 70.6 ± 4.8 years. There were 112 female patients in Group I and 46 female patients in Group II. The patient population was divided into 2 groups based on preoperative serum vitamin D (25-hydroxyvitamin D [25-OHD]) levels (normal range of 25-75nmol/L). Group I included patients with preoperative serum 25-OHD level<25nmol/L. Group II included patients with preoperative serum 25-OHD level ≥25nmol/L. RESULTS The incidence of delirium in this study was 30.2%. In this study, 138 patients (65.1%) had preoperative serum 25-OHD levels <25 nmol/L, and 74 patients (34.9%) had preoperative serum 25-OHD levels ≥25 nmol/L. Preoperative serum 25-OHD levels were associated with postoperative delirium after coronary artery bypass graft surgery. Our retrospective study illustrated that a lower preoperative serum level of 25-OHD was associated with postoperative delirium. Our results showed that 65.1% of patients had preoperative serum 25-OHD levels <25 nmol/L, and this was associated with postoperative delirium. CONCLUSION Vitamin D deficiency exacerbates delirium after coronary artery bypass surgery with cardiopulmonary bypass. Whether the effects of vitamin D deficiency during this event represent separate or interrelated activities with cardiopulmonary bypass is an important question to address and prospective randomized studies are necessary to confirm these results.