Blood Glucose Variability: A Strong Independent Predictor of Neurological Outcomes in Aneurysmal Subarachnoid Hemorrhage

Purpose: In patients with aneurysmal subarachnoid hemorrhage (SAH), increased glucose variability (GV) is associated with increased mortality and cerebral infarction; however, there are no reports demonstrating an association between GV and neurological outcome. This study investigated whether GV had an independent effect on neurological outcomes in patients with SAH in the intensive care unit. Materials and Methods: Consecutive adult patients hospitalized with SAH between January 1, 2009, and May 31, 2015 (N = 122) were retrospectively reviewed. Univariate/multivariate analyses were performed to identify independent predictors of poor neurological outcome. Patients were divided according to the mean glucose level (80-139 vs 140-200 mg/dL) and further subdivided using quartiles (Q) of the standard deviation (SD, representing variability) of the glucose level (Q1, Q2 + 3, and Q4). Results: Unfavorable neurological outcomes occurred in 44.2% of the patients. On multiple regression analysis, age, Hunt and Kosnik grade, SD of glucose (odds ratio [OR], 1.09; 95% confidence interval [CI], 1.02-1.17; P < .01), and minimum blood glucose level (OR, 0.95; 95% CI, 0.91-0.99; P < .01) were significantly associated with unfavorable neurological outcomes. Both groups (mean glucose levels: 80-139 and 140-200 mg/dL groups) had increasing unfavorable neurological outcomes with increasing SD of glucose (Q1, 15.0%; Q2 + 3, 40.0%; Q4, 52.4% and Q1, 44.4%; Q2 + 3, 50%; Q4, 88.9% in the 80-139 and 140-200 mg/dL groups, respectively). Patients with minimum glucose of <90 mg/dL comprised >50% of unfavorable neurological outcome. Conclusion: Increased GV was an independent predictor of unfavorable neurological outcomes in patients with SAH.