title: Mean glucose during ICU admission is related to mortality by a U-shaped curve in surgical and medical patients: a retrospective cohort study.
abstract: BACKGROUND
  Lowering of hyperglycemia in the intensive care unit (ICU) is widely practiced. We investigated in which way glucose regulation, defined as mean glucose concentration during admission, is associated with ICU mortality in a medical and a surgical cohort.
  
  
  METHODS
  Retrospective database cohort study including patients admitted between January 2004 and December 2007 in a 20-bed medical/surgical ICU in a teaching hospital. Hyperglycemia was treated using a computerized algorithm targeting for glucose levels of 4.0-7.0 mmol/l. Five thousand eight hundred twenty-eight patients were eligible for analyses, of whom 1,339 patients had a medical and 4,489 had a surgical admission diagnosis.
  
  
  RESULTS
  The cohorts were subdivided in quintiles of increasing mean glucose. We examined the relation between these mean glucose strata and mortality. In both cohorts we observed the highest mortality in the lowest and highest strata. Logistic regression analysis adjusted for age, sex, Acute Physiology and Chronic Health Evaluation II (APACHE II) score, admission duration and occurrence of severe hypoglycemia showed that in the medical cohort mean glucose levels <6.7 mmol/l and >8.4 mmol/l and in the surgical cohort mean glucose levels < 7.0 mmol/l and >9.4 mmol/l were associated with significantly increased ICU mortality (OR 2.4-3.0 and 4.9-6.2, respectively). Limitations of the study were its retrospective design and possible incomplete correction for severity of disease.
  
  
  CONCLUSIONS
  Mean overall glucose during ICU admission is related to mortality by a U-shaped curve in medical and surgical patients. In this cohort of patients a 'safe range' of mean glucose regulation might be defined approximately between 7.0 and 9.0 mmol/l.
authors.affiliation: Department of Internal Medicine, Academic Medical Centre, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands. s.e.siegelaar@amc.uva.nl
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Siegelaar
authors.forename: Jeroen
authors.initials: J
authors.lastname: Hermanides
authors.forename: Heleen M
authors.initials: HM
authors.lastname: Oudemans-van Straaten
authors.forename: Peter H J
authors.initials: PH
authors.lastname: van der Voort
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Bosman
authors.forename: Durk F
authors.initials: DF
authors.lastname: Zandstra
authors.forename: J Hans
authors.initials: JH
authors.lastname: DeVries
mesh_terms: D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000378:metabolism*; D015331:Cohort Studies; D003422:Critical Care / Q000639:trends; D016638:Critical Illness; D005260:Female; D017052:Hospital Mortality / Q000639:trends; D006801:Humans; D007362:Intensive Care Units / Q000639:trends; D008297:Male; D008875:Middle Aged; D010343:Patient Admission / Q000639:trends; D012189:Retrospective Studies; D012720:Severity of Illness Index
chemical_list: D001786:Blood Glucose