The association of glucose control on in-hospital mortality in the cardiac intensive care unit.

Background: Current guidelines recommend maintaining serum blood glucose (BG) levels between 150 and 180 mg/dL for patients admitted to the intensive care unit (ICU); however, these recommendations are based on randomized controlled trials among general ICU patients and observational studies among specific subgroups. Little is known about the impact of glucose control among patients cared for in the cardiac intensive care unit (CICU).

Methods: This was a retrospective cohort analysis of patients >18 years of age admitted to the University of Michigan CICU from December 2016 through December 2020 with at least one BG measurement during CICU admission. The primary outcome was in-hospital mortality. The secondary outcome was CICU length of stay.

Results: A total of 3217 patients were included. When analyzed based on quartiles of mean CICU BG, there were significant differences in in-hospital mortality across BG quartiles for those with diabetes mellitus (DM) and those without DM. In multivariable logistic regression, age, Elixhauser comorbidity score, use of mechanical ventilation, any hypoglycemic event, and any BG value >180 mg/dL were significant predictors for in-hospital mortality in both patients with and without DM, yet average BG was only predictive of in-hospital mortality in patients without DM.

Conclusions: This study highlights the importance of glucose control in critically ill adult patients admitted to the CICU. The trends in mortality based on quartiles and deciles of average BG suggest a difference in optimal blood glucose levels in those with and without DM. However, regardless of diabetes status, mortality increases with higher average BG.