Glycated hemoglobin A1C and diabetes mellitus in critically ill patients

BACKGROUND: Hyperglycemia has been detected in many critically ill patients in the department of emergency medicine. But its mechanism and prognosis have not been well elucidated. In this study, we measured the serum level of glycated hemoglobin A1C (HbA1c) in critically ill patients to evaluate the effects of hyperglycemia on the prognosis of the patients. METHODS: A total of 826 critically ill patients, who had been treated at the Department of Emergency Medicine of Chaoyang Hospital during October 2006 and November 2007, were divided into a diabetes mellitus group (n=184) and a non-diabetes mellitus group (642) according to whether they had diabetes mellitus. Fasting glucose and HbA1c were measured in all patients. Those in the diabetes mellitus group were further assigned to a drug therapy subgroup and a non-drug therapy subgroup; the serum level of HbA1c and its relationship with short-term outcome were evaluated. RESULTS: Fasting glucose increased in 78.8% of the patients (88.6% in the diabetes mellitus group, and 75.9% in the non-diabetes mellitus group, P<0.05), and HbA1c was elevated in 45.5% of the patients (78.3% in the diabetes mellitus group, and 36.1% in the non-diabetes mellitus group, P<0.01). Fasting glucose, HbA1c and 28-day mortality were improved more significantly (P<0.01) in the drug therapy subgroup than in the non-drug therapy subgroup. The 28-day mortality was more significantly different in patients with fasting blood glucose >8.33 mmol/L than in those with fasting blood glucose <8.33 mmol/L. CONCLUSIONS: Hyperglycemia of critically ill patients could not totally attribute to stress response, especially in those who have no history of diabetes mellitus. Prognosis of hyperglycemia may vary among critically ill patients.