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

Authors Kotfis K, Szylińska A, Listewnik M, Brykczyński M, Ely EW, Rotter I

Received 4 December 2018

Accepted for publication 11 January 2019

Published 20 February 2019 Volume 2019:15 Pages 511—521


Checked for plagiarism Yes

Review by Single anonymous peer review

Peer reviewer comments 2

Editor who approved publication: Dr Roger Pinder

Katarzyna Kotfis,1 Aleksandra Szylińska,2 Mariusz Listewnik,3 Mirosław Brykczyński,3 E Wesley Ely,4,5 Iwona Rotter2

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

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: glycated hemoglobin, POD, mortality, outcome, ICU

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