The interaction of chronic and acute glycemia with mortality in critically ill patients with diabetes.
OBJECTIVE
The relationship between hyperglycemia and mortality is altered by the presence of diabetes mellitus. Biological adjustment to preexisting hyperglycemia might explain this phenomenon. We tested whether the degree of preexisting hyperglycemia would modulate the association between glycemia and outcome during critical illness in patients with diabetes mellitus.


METHODS
Retrospective observational study.


METHODS
Two tertiary intensive care units.


METHODS
Four hundred fifteen critically ill diabetic patients with HbA1c levels measured within 3 months of intensive care unit admission.


METHODS
None.


RESULTS
There were 9,946 blood glucose measurements in this study cohort (glucose measured 6.7 times per day; every 3.6 hrs on average). The median preadmission HbA1c level was 7.0%. There was no significant difference in HbA1c levels (p = .17) or time-weighted average of blood glucose concentrations (p = .49) between survivors and nonsurvivors. The time-weighted average of blood glucose concentrations during intensive care unit stay for nonsurvivors was lower than that of survivors when the HbA1c was >6.8%. In multivariate analysis, we found that there was a significant interaction between HbA1c and the time-weighted glucose level, indicating that the relationship between HbA1c and mortality changed according to the levels of time-weighted average of blood glucose concentrations (p = .008). As a consequence, in patients with higher (>7%) preadmission levels of HbA1c, the higher the time-weighted acute glucose concentration during intensive care unit stay (>10 mmol/L), the lower the hospital mortality compared with the lower HbA1c cohort (<7%).


CONCLUSIONS
In patients with diabetes mellitus admitted to intensive care units, there was a significant interaction between preexisting hyperglycemia and the association between acute glycemia and mortality. These observations generate the hypothesis that glucose levels that are considered safe and desirable in other patients might be undesirable in diabetic patients with chronic hyperglycemia. Further studies are required to confirm or refute our findings.
Egi
Moritoki
M
Department of Anesthesiology and Resuscitology, Okayama University Hospital, Okayama, Japan.
Bellomo
Rinaldo
R
Stachowski
Edward
E
French
Craig J
CJ
Hart
Graeme K
GK
Taori
Gopal
G
Hegarty
Colin
C
Bailey
Michael
M
D000208:Acute Disease; D000368:Aged; D001786:Blood Glucose / Q000032:analysis*; D002908:Chronic Disease; D015331:Cohort Studies; D003422:Critical Care / Q000379:methods; D016638:Critical Illness / Q000401:mortality / Q000628:therapy; D003920:Diabetes Mellitus / Q000097:blood* / Q000188:drug therapy / Q000401:mortality*; D005260:Female; D006442:Glycated Hemoglobin / Q000032:analysis*; D038321:Glycemic Index; D017052:Hospital Mortality; D006801:Humans; D006943:Hyperglycemia / Q000150:complications / Q000175:diagnosis / Q000401:mortality*; D007004:Hypoglycemic Agents / Q000627:therapeutic use; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D011237:Predictive Value of Tests; D011379:Prognosis; D012189:Retrospective Studies; D018570:Risk Assessment; D016019:Survival Analysis
D001786:Blood Glucose; D006442:Glycated Hemoglobin; D007004:Hypoglycemic Agents