Diabetes and risk of community-acquired Staphylococcus aureus bacteremia: a population-based case-control study

Objective: Patients with diabetes may experience higher risk of Staphylococcus aureus bacteremia (SAB) than patients without diabetes due to decreased immunity or coexisting morbidities. We investigated the risk of community-acquired (CA) SAB in persons with and without diabetes. Design: Using population-based medical databases, we conducted a case-control study of all adults with first-time CA-SAB and matched population controls in Northern Denmark, 2000-2011. Methods: Based on conditional logistic regression, we computed odds ratios (ORs) of CA-SAB according to diabetes. We further assessed whether the risk of CA-SAB differed according to various diabetes-related characteristics (e.g. duration of diabetes, glycemic control, and presence of diabetes complications). Results: We identified 2638 patients with incident CA-SAB, of whom 713 (27.0%) had diabetes, and 26 379 matched population controls (2495 or 9.5% with diabetes). Individuals with diabetes had a substantially increased risk of CA-SAB compared with population controls (adjusted OR = 2.8 (95% confidence interval (CI): 2.5-3.1)). Duration of diabetes of = 10 years and poor glycemic control conferred higher risk estimates, with an adjusted OR = 2.3 (95% CI: 1.9-2.7) for diabetes with Hba1c < 7% (< 53 mmol/mol) and an adjusted OR = 5.7 (95% CI: 4.2-7.7) for diabetes with Hba1c >= 9% (>= 75 mmol/mol). The risk of CA-SAB was particularly high in patient with diabetes complications: adjusted OR = 5.5 (95% CI: 4.2-7.2) with presence of microvascular complications and OR = 7.0 (95% CI: 5.4-9.0) with combined macro-and microvascular complications. Conclusions: Diabetes is associated with a substantially increased risk of CA-SAB, particularly in patients with diabetes of long duration, poor glycemic control, and diabetes complications.