Hyperglycemia and mortality in elderly patients with Staphylococcus aureus bacteremia

Objective: To investigate the association between hyperglycemia and in-hospital mortality in elderly patients with Staphylococcus aureus bacteremia (SAB). Methods: We reviewed the medical records of 135 elderly patients with SAB admitted to two tertiary medical centers from January 2003 until December 2004. Patients were stratified into two groups: those with a 7-day post-SAB mean blood glucose < 170 mg/dL and those with a 7-day post-SAB mean blood glucose >= 170 mg/dL. A stepwise logistic regression analysis was performed to determine whether the degree of hyperglycemia was a significant predictor of mortality. Results: Seventy-four (54.8%) patients had methicillin-resistant Staphylococcus aureus bacteremia. During the follow-up period from admission until discharge, 36 (26.7%) patients died. Twenty-one (21.4%) of 98 patients with a 7-day post-SAB mean blood glucose <170 mg/dL died, while 15 (40.5%) of 37 patients with a 7-day post-SAB mean blood glucose >= 170 mg/dL expired. Multivariate analysis identified 3 independent determinants of death: Simplified Acute Physiology Score (SAPS) score at onset of SAB >45 (OR 5.3, 95% CI {1.8, 15.5}, P = 0.002), a 7-day post-SAB mean blood glucose >= 170 mg/dL (OR 3.3, 95% CI{ 1.2, 9.2}, P = 0.03), and altered mental status at the onset of SAB (OR 7.8, 95% CI {2.5, 23.9}, P = 0.0003). Conclusions: Hyperglycemia is an important marker of increased mortality among hospitalized elderly patients with SAB.