Diabetes Patients and Staph Infection Risk

Diabetes patients have nearly a three-fold higher risk of community-acquired Staphylococcus aureus bacteremia, particularly among patients with disease of long duration, poor glycemic control, and diabetes complications, according to a new study.

Diabetes may increase the risk of Staphylococcus aureus bacteremia to coexisting morbidities, including foot ulcers and kidney disease, and potentially diabetes-related decreased immunity, according to the researchers, led by Jesper Smit, MD, of the Department of Clinical Microbiology, Aalborg University Hospital, Aalborg, Denmark.

Staphylococcus aureus is a leading cause of bacteremia, and is associated with a 30-day mortality of 20-40%, the researchers noted. However, there has been little evidence to support the belief that diabetes increases the risk of infection with these bacteria.

“To our knowledge, no prior study has investigated diabetes as a risk factor for S aureus bacteremia as the main exposure,” they stated.

The researchers published their results online in European Journal of Endocrinology.

Using population-based medical databases, they conducted a case-control study of all adults with first-time community-acquired Staphylococcus aureus bacteremia and matched population controls in Northern Denmark, 2000-2011.

They identified 2,638 patients with incident community-acquired Staphylococcus aureus bacteremia; 713 of these patients (27%) had diabetes. These patients were matched with 26,379 controls; 2,495 of them (9.5%) had diabetes.

Those with diabetes had a substantially higher risk of community-acquired Staphylococcus aureus bacteremia compared with population controls, with an odds ratio (OR) of 2.8. That OR rose to 3.8 among those with a disease duration of 10 or more years.

Poor glycemic control also led to higher risk estimates, with an adjusted OR of 2.3 for diabetes with an HbA1c level of less than 7% and an adjusted OR of 5.7 for diabetes with an HbA1c level of 9% or higher.

The risk of community-acquired Staphylococcus aureus bacteremia was particularly high among patients with diabetes complications, with an adjusted OR of 5.5 for those with microvascular complications and OR of 7.0 for those with combined macrovascular and microvascular complications.

The presence of type 1 diabetes increased the risk of Staphylococcus aureus bacteremia, with an OR of 7.2 compared with controls, as compared to an OR of 2.7 among type 2 diabetes patients. The researchers noted that there were only 40 patients with type 1 diabetes and 29 controls with type 1 disease, and therefore the differences in risk from those with type 2 diabetes should be interpreted cautiously.

They stated the results “extend the limited existing knowledge on the risk of community-acquired S aureus bacteremia in patients with diabetes.”

The researchers concluded that “these results emphasize the importance of improved preventive care for patients with diabetes, including optimized glycemic control and particularly good infection surveillance among patients with long duration of diabetes and complications.”

Reference: Smit J, et al. Diabetes and risk of community-acquired Staphylococcus aureus bacteremia: A population-based case-control study. Eur J Endocrinol. 2016 Mar 10. [Epub ahead of print]