Admission blood glucose predicts mortality and length of stay in patients admitted through the emergency department

Background: Hyperglycaemia has been associated with adverse outcomes in several different hospital populations.

Aim: The aim of this study was to investigate the relationship between admission blood glucose level (BGL) and outcomes in all patients admitted through the emergency department.

Methods: This study was a retrospective observational cohort study from an Australian tertiary referral hospital. Patients admitted in the first week of each month from April to October 2012 had demographic data, co-morbidities, BGL, intensive care unit admission, length of stay and dates of death recorded. Factors associated with outcomes were assessed by multi-level mixed-effects linear regression.

Results: Admission BGL was recorded for 601 admissions with no diagnosis of diabetes and for 219 admissions diagnosed with type 2 diabetes (T2DM). In patients with no diagnosis of diabetes, admission BGL was associated with in-hospital and 90-day mortality (P < 0.001). After multivariate analysis, BGL greater than 11.5 mmol/L was significantly associated with increased mortality at 90 days (P < 0.05). In patients with T2DM increased BGL on admission was not associated with in-hospital or 90-day mortality but was associated with length of hospital stay (β: 0.22 days/mmol/L; 95% confidence interval 0.09-0.35; P < 0.001), although this association was lost on multivariable analysis. In patients with T2DM, increased coefficient of variation of BGL was also positively associated with length of hospital stay in an almost dose-dependent fashion (P < 0.001).

Conclusion: Admission BGL was independently associated with increased mortality in patients with no diagnosis of diabetes. Glycaemic variability was associated with increased length of hospital stay in patients with T2DM.