Diabetes mellitus and community-acquired bloodstream infections in the critically ill

IntroductionCommunity-acquired bloodstream infections have not been studied related to diabetes mellitus in the critically ill.HypothesisWe hypothesized that the diagnosis of diabetes mellitus and poor chronic glycemic control would increase the risk of community-acquired bloodstream infections (CA-BSIs) in the critically ill.MethodsWe performed an observational cohort study between 1998 and 2007 in 2 teaching hospitals in Boston, Massachusetts. We studied 2551 patients 18 years or older, who received critical care within 48 hours of admission and had blood cultures obtained within 48 hours of admission. The exposure of interest was diabetes mellitus defined by International Classification of Diseases, Ninth Revision, Clinical Modification, code 250.xx in outpatient or inpatient records. The primary end point was CA-BSI (< 48 hours of hospital admission). Patients with a single coagulase-negative Staphylococcus positive blood culture were not considered to have bloodstream infection. Associations between diabetes groups and bloodstream infection were estimated by bivariable and multivariable logistic regression models. Subanalyses included evaluation of the association between hemoglobin A1c (HbA1c) and bloodstream infection, diabetes and risk of sepsis, and the proportion of the association between diabetes and CA-BSI that was mediated by acute glycemic control.ResultsDiabetes is a predictor of CA-BSI. After adjustment for age, sex, race, patient type (medical vs surgical), and acute organ failure, the risk of bloodstream infection was significantly higher in patients with diabetes (odds ratio [OR], 1.42; 95% confidence interval [CI], 1.10-1.82; P = .006) relative to patients without diabetes. The adjusted risk of bloodstream infection was increased in patients with HbA1c of 6.5% or higher (OR, 1.31; 95% CI, 1.04-1.65; P = .02) relative to patients with HbA1c less than 6.5%. Furthermore, the adjusted risk of sepsis was significantly higher in patients with diabetes (OR, 1.26; 95% CI, 1.04-1.54; P = .02) relative to patients without diabetes. Maximum glucose did not significantly mediate the relationship between diabetes mellitus diagnosis and CA-BSI.ConclusionsA diagnosis of diabetes mellitus and HbA1c of 6.5% or higher is associated with the risk of CA-BSI in the critically ill.