Diabetes and elevated preoperative HbA1c level as risk factors for postoperative delirium after cardiac surgery: an observational cohort study

Katarzyna Kotfis; Aleksandra Szylińska; Mariusz Listewnik; Mirosław Brykczyński; E Wesley Ely; Iwona Rotter

doi:10.2147/NDT.S196973

Diabetes and elevated preoperative HbA1c level as risk factors for postoperative delirium after cardiac surgery: an observational cohort study

Neuropsychiatr Dis Treat. 2019 Feb 20:15:511-521. doi: 10.2147/NDT.S196973. eCollection 2019.

Authors

Katarzyna Kotfis¹, Aleksandra Szylińska², Mariusz Listewnik³, Mirosław Brykczyński³, E Wesley Ely^{4

5}, Iwona Rotter²

Affiliations

¹ Department of Anesthesiology, Intensive Therapy and Acute Intoxications, Pomeranian Medical University, Szczecin, Poland.
² Department of Medical Rehabilitation and Clinical Physiotherapy, Pomeranian Medical University, Szczecin, Poland, aleksandra.szylinska@gmail.com.
³ Department of Cardiac Surgery, Pomeranian Medical University, Szczecin, Poland.
⁴ Division of Allergy, Pulmonary, and Critical Care Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA.
⁵ Geriatric Research, Education and Clinical Center (GRECC) Service, Department of Veterans Affairs Medical Center, Tennessee Valley Healthcare System, Nashville, TN, USA.

Abstract

Introduction: Postoperative delirium (POD) is a common complication of cardiac surgery associated with increased mortality, morbidity, and long-term cognitive dysfunction. Diabetic patients, especially those with poor diabetes control and long-standing hyperglycemia, may be at risk of developing delirium. The aim of this study was to analyze whether the occurrence of POD in cardiac surgery is associated with diabetes or elevated preoperative glycated hemoglobin (HbA1c) level.

Materials and methods: We performed a cohort analysis of prospectively collected data from a register of cardiac surgery department of a university hospital. Delirium assessment was performed twice a day during the first 5 days after the operation based on Diagnostic Statistical Manual of Mental Disorders, fifth edition criteria.

Results: We analyzed a cohort of 3,178 consecutive patients, out of which 1,010 (31.8%) were diabetic and 502 (15.8%) were diagnosed with POD. Patients with delirium were more often diabetic (42.03% vs 29.86%, P<0.001) and on oral diabetic medications (34.66% vs 24.07%, P<0.001), no difference was found in patients with insulin treatment. Preoperative HbA1c was elevated above normal (≥6%) in more delirious than nondelirious patients (44.54% vs 33.04%, P<0.001), but significance was reached only in nondiabetic patients (20.44% vs 14.86%, P=0.018). In univariate analysis, the diagnosis of diabetes was associated with an increased risk of developing POD (OR: 1.703, 95% CI: 1.401-2.071, P<0.001), but only for patients on oral diabetic medications (OR: 1.617, 95% CI: 1.319-1.983, P<0.001) and an association was noted between HbA1c and POD (OR: 1.269, 95% CI: 1.161-1.387, P<0.001). Multivariate analysis controlled for diabetes showed that POD was associated with age, heart failure, preoperative creatinine, extracardiac arteriopathy, and preoperative HbA1c level.

Conclusion: More diabetic patients develop POD after cardiac surgery than nondiabetic patients. Elevated preoperative HbA1c level is a risk factor for postcardiac surgery delirium regardless of the diagnosis of diabetes.

Keywords: ICU; POD; glycated hemoglobin; mortality; outcome.