The impact of early hypoglycemia and blood glucose variability on outcome in critical illness.
BACKGROUND
In critical illness, the association of hypoglycemia, blood glucose (BG) variability and outcome are not well understood. We describe the incidence, clinical factors and outcomes associated with an early hypoglycemia and BG variability in critically ill patients.


METHODS
Retrospective interrogation of prospectively collected data from the Australia New Zealand Intensive Care Society Adult Patient Database on 66184 adult admissions to 24 intensive care units (ICUs) from 1 January 2000 to 31 December 2005. Primary exposure was hypoglycemia (BG < 4.5 mmol/L) and BG variability (BG < 4.5 and >or= 12.0 mmol/L) within 24 hours of admission. Primary outcome was all-cause mortality.


RESULTS
The cumulative incidence of hypoglycemia and BG variability were 13.8% (95% confidence interval (CI) = 13.5 to 14.0; n = 9122) and 2.9% (95%CI = 2.8 to 3.0, n = 1913), respectively. Several clinical factors were associated with both hypoglycemia and BG variability including: co-morbid disease (P < 0.001), non-elective admissions (P < 0.001), higher illness severity (P < 0.001), and primary septic diagnosis (P < 0.001). Hypoglycemia was associated with greater odds of adjusted ICU (odds ratio (OR) = 1.41, 95% CI = 1.31 to 1.54) and hospital death (OR = 1.36, 95% CI = 1.27 to 1.46). Hypoglycemia severity was associated with 'dose-response' increases in mortality. BG variability was associated with greater odds of adjusted ICU (1.5, 95% CI = 1.4 to 1.6) and hospital (1.4, 95% CI = 1.3 to 1.5) mortality, when compared with either hypoglycemia only or neither.


CONCLUSIONS
In critically ill patients, both early hypoglycemia and early variability in BG are relatively common, and independently portend an increased risk for mortality.
Bagshaw
Sean M
SM
Division of Critical Care Medicine, University of Alberta Hospital, University of Alberta, 8440-112 ST NW Edmonton, Alberta, Canada. bagshaw@ualberta.ca
Bellomo
Rinaldo
R
Jacka
Michael J
MJ
Egi
Moritoki
M
Hart
Graeme K
GK
George
Carol
C
D016638:Critical Illness / Q000453:epidemiology* / Q000401:mortality; D005260:Female; D044882:Glucose Metabolism Disorders / Q000453:epidemiology* / Q000401:mortality; D017052:Hospital Mortality; D006801:Humans; D007003:Hypoglycemia / Q000453:epidemiology* / Q000401:mortality; D015994:Incidence; D007362:Intensive Care Units; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009520:New Zealand / Q000453:epidemiology; D011379:Prognosis; D012189:Retrospective Studies