Blood glucose on day of intensive care unit admission as a surrogate of subsequent glucose control in intensive care

Purpose: The aim of the study was to test whether the mean of the highest and lowest glucose values on day 1 (Glu₁) is a useful surrogate marker of mean blood glucose during the totality of intensive care unit (ICU) stay (Glu_tot). Materials and Methods: Glu_tot values were extracted from electronically stored biochemical databases (point-of-care laboratory) and Glu₁ values from electronically stored prospectively collected patient databases in ICUs of 4 hospitals from January 2000 to October 2004. Statistical assessment of relationship between Glu₁ and Glu_tot was done. Results: There were 197 227 blood glucose measurements for 8039 patients. The average of all blood glucose measurements was 8.22 ± 2.75 mmol/L. The difference between the average of all glucose values (N = 197 227) and average of Glu₁ (n = 8039) was 0.17 mmol/L. This difference in each hospital was also small (0.26, -0.13, 0.12, and 0.37 mmol/L, respectively). Conclusions: Glu₁ was a good predictor of Glu_tot across all study hospitals. This observation makes it possible to use Glu₁ as a surrogate of glucose control during ICU stay and opens the door to understanding ICU glucose control across the whole of Australia and New Zealand.